Why Do My Mountain Bike Disc Brakes Feel Spongy? |

Over time, your MTB disc brakes can start to feel a bit spongy or vague in their bite point; and they may seem to lack the power they once had. There are a few reasons for this, in this video we’ll go over them and provide some solutions.
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[@SmokeySkies]

I'm very grateful for this video, mine was the left piston stuck and not pushing through.. this video didn't just fix my breaks but also spread out my pistons so that i get no scraping on the rotor and my break feels better than it did when i first bought the bike and it wasn't even second hand but brand new.

[@michaellambert5974]

GMBN is my go to channel for useful tips and tricks. This video is a prime example of that. I have used the mini bleed with success in between full bleeds. Thanks GMBN.

[@specialized500]

I had a pair of original Shimano deore hydraulic brakes that lasted 23 years with only a few oil changes and occasional burping to expel some air. No fancy bleed kits needed . Now I have modern deore set up which need far more maintenance .

[@daylightsensor8695]

very informational video! I never knew about the hydrophilic attributes of Dot. keep em coming!

[@quesoner34]

@gmbntech Even had some new hacks for a seasoned mechanic! Over-Night thing on Shimano works actually. Though instead of waiting, I usually just push some new oil from the bottom up. Takes me like 20min at the shop (I work at) and ensures I get rid of ANY bubbles!

[@cancer8343]

Just the video I was waiting for!

[@kennethcolbert2921]

Thanks I am switching my brakes to hydraulic on my Surly Disc Trucker over the winter. I had cable brakes for a long time.After watching a lot of videos on bicycle brakes I made my mind up to switch.I will have a lot of time to do this it's getting colder here in Maine/USA. I have learn a lot from your videos and I use Park Tools only and Shimano parts for the most part.

[@JurisKankalis]

The tools or the parts don't matter that much - it's what's in the head and how you use it :) Anyway - even now, in 2022 - some of my bikes have V-brakes - and I cannot complain. Although disc brakes, if chosen wisely (I have extremely good experience durability-wise with Avid Juicy series) are much less needy for maintenance than V-brakes - the latter still offer plenty of power and precision (especially if older Shimanos with paralelograms are used, eg., LX, XT or XTR), plus the ethereal weight-saving aspect.

[@uditnaik5852]

Brilliant !!! Out of the countless videos and advice I have seen on youtube about how to fix squishy and squealing brakes, this video has the most useful and has the most crucial tip that the rest of the videos have ignored and that is the contamination of the brake pistons and how important is it to clean them once in a while. I have wasted quite a few days trying bleeding brakes, chasing phantom bubbles, cleaning rotors and smoothening brake pads with sand paper just to get brakes working right and stop making noise.. GMBN rocks as usual!!

[@richardjones2811]

Great video and lots of great tuition 👍 Just wish this info was freely available 15 years ago.

[@martinduplak3205]

wow this actually helped me a lot. thanks

[@floppydisk1137]

My shimano front brake has a little bit of air that I can get it out of the system. I consider it as modulation. 😁

[@z06trk]

I’ve also done the “modulation bubble mod” to the MT7 up front. ( ͡° ͜ʖ ͡°)

[@theplacedowntheroad]

It's a feature!

[@lakaldrak]

yes same reason i didnt bleed mine :)

[@just_delightful]

Great video Gregg!

[@mrjamieholloway]

one thing you did not mention, which is pretty common is the disks that are worn/warped because pads are not maintained, and this can push the pads out, also making it feel spungy.

[@jonathanzappala]

Please bring back time stamps 🥺

[@mountainshredder1471]

Love the video Doddy!

[@scrooge1374]

In Panama with our climate some brands (depends of the oil brand) will lock when is warmer, seen people having to spray water on calipers or not let the bike stand in the sun to long.

[@fishingwiththomas]

I bled my xt icetechs for the first time in 9 years today.

[@OscarRodriguez-ez2kb]

💀👍🏼

[@chadson5244]

Shimmy ya

[@SnootchieBootchies27]

Did concentrated dark matter come out?

[@matmatteo8238]

@@SnootchieBootchies27 More like "did you have oil in your pneumatic diks brake?"

[@bendaff9618]

@@matmatteo8238 lol

[@rupedog]

4mm allen key fits SRAM calipers perfectly between caliper body so u can perfectly center the pistons

[@ivarvsivtsev3771]

#AskGMBNTech Hey guys, I have a fox 36 performance elite FIT4 and I’m wondering if I need to use fox float fluid in my air camber or the suspension grease is enough? Also what about the rear shocks? Thanks!

[@clemens8744]

#AskGMBNTech How strong is continental's proTection Apex carcasse in comparison to Schwalbe's Super Gravity? 'm very curious that they can be comparible in terms of puncture/burping resistance as contintal's are almost 300g lighter

[@winstonshaw2533]

brilliant video thanks 😊 👍

[@Jydmd]

My cheapo (Shimano MT200) is schreaching pretty loud and feels not very powerful. The bike is relatively new (it was ridden from August to October last year), and the rear brake is working perfectly, so I don't think they need a bleed that soon... Both levers have a tiny bit of play, but it doesn't seem to affect the rear brake anyway.

[@rupedog]

Clean.up pads and rotor, deglaze pads and re bed in.the front pads

[@jasonboussum3924]

This is very helpful.

[@walterreyes7664]

My shimano xt 8120 front brake have been acting out 😩😩😩😩😩,severe rubbing...Thanks for the video....👍👍👍

[@Insert_name_below]

#askgmbntech hi, I have a bike with a 3x8 and am just wondering, what would be the issue with just buying a narrow wide chainring and taking my chainrings off, I was told by a bike shop that it would mess up the chain line, but I don’t understand how the chain line would even change as it would be sitting right where my middle chainring would sit, I do not understand the purpose of needing a full new drivetrain for a 1x conversion, my friends have did ghetto 1x conversions and it didnt effect the bike at all in a negative way

[@theonlyalan731]

If your brake levers are spongy, it's usually because they are Sram

[@rupedog]

Or Shimano on going and common wandering bite point issue...scary...pull the brakes, nothing happens, until u pump them...why havent they fixed it, still ongoing after 2+years.... mentioned on nearly ever new bike review with deore and above shimano's. Such a Shame.

[@StrGzr101]

Perhaps you just didn't know how to dial them in. Mine are fantastic through Florida humidity, salt, and muck. 😎

[@ziencodm]

Yes

[@BrodeOne]

😂 ok I can't agree more. I try to fix this 🫣 help me

[@kurtislewis3334]

Mine are sram😂

[@jp2246]

Super helpful video

[@chrisridesbicycles]

The standard clamp for the bleeding hose on Shimano brakes is horrible to use. Do you know a better option?

[@Dummatzen]

I have tried the vertical hanging off my bike after a brake replacement. It made a ton of difference. I just let i hang over night and them did a mini bleed. Now the breaks are sharp and crisp.

[@Juancena-xb8mp]

Can u tell me how u did it?? Step by step

[@Dummatzen]

@@Juancena-xb8mp I will try. So what you do is that you open the bleed screw on the brake lever. Then you hang the bike ( I used a mech stand) so that your bike hangs vertically with the break lever as high as possible. You do have to make sure that the lever is horizontally level. If you have a bleed funnel it is best to have in screwed in on your lever. Than you loosen your caliper and let it hang down. Do not open the bleed valve on the caliper. Then you just let it hang there for 12 hours and gravity should do the trick. bubbles should rise to the top and Bob's your uncle!

[@smonnyfy]

#askGMBNTech how does thr new Trek Session's extended headset cup work? To my knowledge, the upper crown stays at the same position, so only thing that changes is the height between crowns, am I right?

[@HWDominic]

I have a fairly new bike. When I pull the lever until I feel resistance it slows the bike, however I can still further squeeze the lever hard to the point it will touch my handlebar grips, and at this point the brakes will barely even lock up. I was told this was due to air in my system. hopefully a bleed will solve this.

[@markdavies3151]

Did you manage to solve this with a bleed or was it something else?

[@HWDominic]

@@markdavies3151 Bled the brakes, get a very slight increase in braking power. Turns out I've just got rubbish brakes (Tektro). I've been advised to invest in some Shimanos, even cheap ones should easily out perfrom my tektros... My friend's cabled Shimanos have been stopping power than my Tektro hydraulics....

[@veejay2901]

Hi Doddy, can you please show us what to do when trying to bleed but the syringe won't move. It appears the system is blocked?

[@sauceman9499]

I have cheap siv simaers hydraulic brakes and the calipers can be separated into two so it doesn't bother me if i accidentally squeeze the lever and pop the piston and i can clean or replace the seals or piston easy

[@mtbboy1993]

if you use mechanical brakes: the barrel adjuster loosened at the brake lever, so use pliers to tighten them, on the trail Wolftooth pack pliers are great for that. you use wrong cables/hoses brake lever body is too flexible one brake pad is too far out. lever reach got changed due to loose reach adjust bolt, some brake levers might have bolt in the lever body, and loosen no matter what, might need to glue it or use red Loctite, but in brake lever blade, it won't be an issue for sure.

[@Daniel_lebieR]

Hi there @GMBN Tech #askGMBNTech -- Question regarding 11:18 . Since "hydrophobic" means "afraid of water" ==> no *water* will get in the system. Air may get in though, since "air molecules" are not charged/do not have a dipole. Question therefore: Do the air bubbles in a mineral-oil system actually come from boiling water (if so ==> higher density, therefore at the bottom of the brakes//oil floats on water), or is it just "plain air" in that case? Thanks in advance. I'm really enjoying your videos. Keep up the good work!

[@davidcrowson4745]

Thank you

[@KingVita-mf6xu]

#AskGMBNTech I do have a new bike (3 weeks old) with SRAM CODE RSC breaks with an issue like that: if I pull the leaver about 3 times the bitenig point ist rock solid but pulling first time it's spongy (leaver goes to the bars). Bleeding was done 3 times now... problem seems to be gone but after time it's again spongy... Break pads are fine and metallic type from sram...What I noteticed is that this little rubber plug at the bleeding edge port ist just a tiny wet...could be there a leaking problem? what could I check else? Thanks a lot!

[@runevw2446]

#askGMBNTech Hey, Doddy how much oil/grease do you need in a free hub? thanks!

[@UKSHARPSHOOTER78]

Can you use two stroke mineral brake oil in hydro breaks that use mineral oil

[@davezeraschi7936]

One half of a wooden clothes peg works well for pushing the pistons back 😊

[@UndeadNaziKilla]

So I've only had two times my brakes have felt spongy. First my pads were completely worn. Then second time I found out yesterday, was my rear pads were half sticking out... the holding pin was gone 😑

[@jinavl]

I gotta say, learning to jump at 43 this week has been awesome..went riding 5 times this week and I just figured it out on my own..it's actually easy once you get it..

[@dabooge]

Just don't crash. We don't heal as quickly at this age

[@jinavl]

@@dabooge I know it sucks but I'm in better shape than my kids..lol

[@mrfrogg46able]

awsome. i'm 56 and i ride better now than in my teens.

[@mrfrogg46able]

@@dabooge too true

[@JurisKankalis]

Jeeeesus. Got still 3 more years for practicing at that pace. Mommy I'm afraid of that big air!!!

[@silverbullit2011]

DO NOT USE an Allen key or any hard steel tool in between your Shimano or any ceramic pistons when extending them for cleaning. You will crack them by doing this. That is not covered by any warranty. That is a new caliper if you do this and you cant get new pistons for Shimano systems they are not offered and you will not find any stock of those calipers for a year easy here in the states. Use a modified plastic yellow Shimano bleed block. Essentially it is a bleed block with one side taken away for one piston to extend and press against a wide flat and much softer surface then an Allen key. Ask any Shimano technician or Look it up Shimano S.T.E.C training. Love the show but that is a bad technique.

[@nestorcepeda9189]

I have the epic bleed solutions universal kit and it took 3 months to arrive

[@KD_VLOG]

Which hydraulic break is best for hardtrail under best budget please reply i am from Nepal 🇳🇵

[@deadz0neguitars108]

#AskGMBNTech Hi, Doddy, I installed CushCore tire inserts for the first time. Installation went smoothly, but the insert causes a tire wobble even though the bead is set. Is this safe to ride or will it onset premature wear?

[@mtbboy1993]

the insert should not cause this, I suspect the tyre is not fully seated, and yes riding it like this will cause premature wear on the tyre, and uneven wear, thus tyre will be messed up after you correct it. so to solve it let air out push tyre into centre of rim, and pump until whole bead is seated, make sure the line on the side wall is even.

[@smallhatshatethetruth7933]

Pipe cleaners are handy for cleaning the pistons, wrap them around the pistons

[@a1d8a2m]

Smart hack.

[@rupedog]

Electric toothbrush...with an old head on!

[@LaurentiusTriarius]

I've had a deal on a set of tektro orion 4p years ago it was running fine, bit spongy but still firm enough. So when I was shopping for 2023 bikes I bought one with the tektro Orion 4p thinking one less thing to upgrade right away, they feel super spongy no matter the mineral oil of bleed method I use they feel like junk. I tried to have them replaced under warranty but apparently they all feel like that it's normal. Lame

[@Milessongs]

What might cause my Rear SRAM Level TL brake lever to return slowly? (squeeze it and it doesn’t snap back) This symptom led me to try a bleed. I noticed the pistons not activating well, but a good clean and bleeding the line got them going. But that lever still doesn’t spring back as quickly as the other, Front lever. #askgmbntech

[@bobbyhempel1513]

#askGMBNtech the cup that came with my bleed kit does not fit the threads on my brake fluid reservoir is there another size cup that I'm unaware of because I bought four different brake bleed sets and they all have the same size thread

[@JohannesDeselaers]

#askGMBNTech Hey Doddy, hey GMBN - Do I need to open the bleed port on the brake lever when pushing the pistons back into the caliper? Or more specicfically: Do some Shimano brake levers have overpressure relief valves? When pushing back the pistons on my Deore XT brake (BR-M8120 with BL-M8100 lever) some brake fluid pushed out of the lever with a small popping sound - not out of the bleed port that is, but rather out of the circular end of the brake reservoir. I suppose the system was overfilled. I cleaned up, did a bleed of the system - no more leakage afterwards. But I am wondering if I damaged something and should replace the lever? Cheers, Johannes

[@jaden3393]

The side piece is a pressure relief valve

[@ANDRITSOULAS]

Hi. I just bought a new bike. I have done about 30km until now . Even if i haven't use it almost at all my rear brake feels way spongier than my front one . Shimano mt 500 set internally routed the rear one. Talked with my service but they told me to use them some more and check them after . Both front and rear stop the bike with Great power. Thanks in advance

[@rupedog]

Couldbe Shimano wandering bite point issue, or if just spongey then air in system, or contaminated from lube spray

[@ilandeboer242]

hey GMBN tech i have a problem... my rear brake makes a tick noise when i brake. my local bike shop doesn't know what it is, can you help me out? i got hydraulic disc brakes

[@thecrazyracoon]

What about if the lever slowly ends up closer to the bars as you ride down the mountain? Is this brake fade or just air on the lines? Tektro hydros

[@jaden3393]

Tektro brakes arnt it id say get deores but yet again you need a bleed for the tektro

[@tcarnell79]

"Sticky Pistons" What a band name THAT is !!!

[@Paulsbikeandboard]

#askgmbntech I have spare brake pads and I can’t remember if I bought sintered or semi metallic. Packaging is long gone. Any way to tell based on the pad? Not seeing any markings printed.

[@MaplePanda04]

Full metallic is, well, full metallic. They look like metal blocks, usually copper/brass colored. Organic/semi pads will have some little shavings of shiny metal mixed with a dark, non-metallic binder.

[@jackschnabel856]

I just got a brand new Trek marlin 6 and it's my first time using hydraulic disc brakes. I absolutely can't brake with one finger like most people say, if I want the tires to lock up I need to squeeze super hard. My old bike that has rim brakes stops significantly easier, I could use 1 finger on that. Idk what's wrong with it, the levers aren't squishy like air is in them and I tried to bed the brake pads in as best I could

[@rupedog]

Contaminated pads/discs for sure. Clean and bed in properly...

[@randommountainbiker9305]

#AskGMBNTech just wondering if you can fit a 27.5x2.30 tyre on a 27.5x2.20 rim. Any rear tyre suggestions?

[@liamjones4636]

you can just dont go more than 2,5 i would say

[@manueldeubler1127]

Really good 'tool' for cleaning disc brake pistons are pipe cleaners.

[@JurisKankalis]

Thanks for the advice - but older Avid Juicy 3 and 5 (haven't used 7, Carbon or Ultimate that much) seem to last forever w/o any maintenance - newer Elixir brakes seem to have problems around leaky lever pistons/seals very often.

[@Activate172]

#AskGMBNTech Hi Doddy, Whenever I try to do any kind of rough trails on my bike I get pain in my lower back. Is this down to my setup or could it just be down to poor technique? Thanks

[@janeblogs324]

Existing injury I'd said. Hang from a pull up bar. Twist your hips (back) 90° a few times, straighten then bring each knee up to your chest. Pain should vanish for a week, but repeat this exercise for months and you'll strengthen your lower back for good

[@mtbboy1993]

might be misaligned lower back, I can't ride a hardtail in rough terrain cus it guaranties thrown out back and neck. but back issues can be too riding a bike with too long or too short reach, but yes bad technique too, but you must be doing something really wrong then. it's unlikely you ride in an absurd position. but suspension setup might be bad, geometry might be bad, along with too short reach, causing you get a head banging effect, you might also get issue with the back too.

[@lindsaypatton8374]

Where would this bike shipped from?

[@LJS1605]

#AskGMBNTech I was wanting to raise the front end of my bike. Really wanting to know what is the difference between MORE SPACERS VS HIGHER RISE BARS. (And how each will affect the feel of the bike.)

[@harrybryson1130]

If you add spacers, it reduces reach (as the handlebars come back towards you and up), but the higher rise bars don’t effect reach. That’s the short of it really

[@LJS1605]

@@harrybryson1130 presumably you could tilt the bars back though to reduce it

[@harrybryson1130]

@@LJS1605 in theory yes, but I think it wouldn’t look as good 🤷🏻‍♂️

[@harrybryson1130]

And also, that would mess with the backsweep and stuff and probs wouldn’t be as comfortable either

[@JurisKankalis]

The reason might be unknown (straighter back?), but climbing performance will suffer severely, because you won't be able to plant (or steer, or do anything from then on) your front wheel in extremely steep climbs.

[@TonyLing]

But why do brakes 'pump up'? What crucial parameter changes when the lever goes from soggy to firm after a few pumps?

[@hugotw4862]

When i had my bike upside down to remove my rear wheel on the go my rear brake didn’t work for like 30 secs, that indicates air in the system right?

[@Justin-Walsh]

Yes it is.

[@viethknorr5389]

#askgmbntech i have a old mavic sup rim and i want to ride it tubeless is it possible?

[@linovalentino2441]

#AskGMBNTech Hey doddy my name is Lino I have a Giant Trance X 29er and I have 150mm of travel on my RockShox fork should I add more?

[@cheshire_]

After multiple attempts I finally got it, it's so hard on my bike to tap the brake line because it's inside the bike frame Hope it won't happen again any time soon, last time I bled them 3 times and they became spongy after couple of km's, wasting my time and money on brake oil...

[@stoneschanify]

Why would you put oil on the pistons to contaminate the brake pads?

[@harrybryson1130]

#askgmbntech I got a new bike at the start of February, and I adjusted my brake lever reach to suit my small hands. Only thing is, my back brake acts as if it needs bled sometimes and pulls to the bar, which can be remedied by extending the brake lever reach and readjusting it. My front brake has no problems, so what’s happening and how can I fix it?

[@harrybryson1130]

it’s a shimano (deore I think) lever

[@rupedog]

@@harrybryson1130 this explains it. Shimano has had an issue on its brakes with wandering bite point fir ages. Some have it, some dont. They should replace under warranty if u advise its 'wandering bite point'. No guarantee the new one will be better. Its a lottery. Shimano havent resolved it in over 2 years!. Very widely documented in mtb press. Only seems to effect their deore and above brakes tho.

[@biggaywizard]

The Park Tools bleeding kit sucks, I had to warranty the Sram one three times and it still leaks.

[@mclaren44]

can you do the lever bleed on other brands or only shimano? clarks m2 to be precise need to shorten a hose and dont fancy a full bleed

[@SnootchieBootchies27]

Just my opinion, but I would consider shortening a hydraulic line to be a major modification to a hydraulic brake system. I would do a full bleed just to be thorough.

[@rvrside10291]

Shortening a brake hose is actually surprisingly easy, plus it doesn't require a brake bleed! There are some great tutorials on KZbin on how to do it, all you need is a replacement olive + bark kit, something to hold the hose while you fit the new barb and a small (usually 8mm) spanner to 'crush' the olive. But yes, you can lever bleed/ tap out any bubbles that may get trapped on levers other than shimano. Most tutorials I've used are from Park Tool/ or the GMBN/ GCN channels. In fact, the one I learnt hose shortening from, is on GMBN!

[@BlbecBlb]

#AskGMBNTech What do you think is better upgrade on 500$ bike 3x9 to 1x12; coil to air fork; normal to telescopic seat post; or something else? What would make a most difference?

[@trialsta1]

Dropper post all day long, they're a revelation

[@d0ominus53]

What are those grips

[@7eyes756]

I feel like everyone should know this i had my brake bleed and my pistons replaced but a week passed and same thing happend my breaks got sqeaky again so i tought to my self what if the mineral oil is not reaching the leaver so what i did i removed the leaver placed it verticaly in my hand and started pressing it and my hydraulic breaks got they'r power back mabie it's just my model or something like that but i feel like i have to share this with people that have the same problem

[@danielolave9146]

#askGMBNTech Hi Doody. Love the channel and the show. I have a 2020 Scott Genius 950 size medium. It has a Fox float 34 150mm of travel with twinlock system. It is my first full suspension bike. I’m loving it. I bought it because I like how versatile it is. I use it as a trailbike even bikepacking. I like swapping 29 and 27.5+ wheels around. I’m planning to do some enduro races as soon as the pandemic ends. I know some EWS riders as Martin Maes run 150 mm travel both front and rear. I’m 1.73cm height and 95 kg. I’m a bit worry about the thin 34mm upper legs for rough trails and jumps. I was wondering if I fit a Fox 36 with 160mm travel, would that mess up the geometry? What if I set the flip chip of the rear shock to the high position? Would that help? Greetings from Chile.

[@JurisKankalis]

....it would be crazy if those 2 mils actually improved rigidity as much as you'd like - remember, 20 years ago everyone was riding 30 and 32 mm forks - and I don't think broken forks were more of a problem than now.

[@POVMTB1]

ive got shimano saint brakes on my 2 bikes, on my dh the leaver is light and consistent, on my trail,, no matter how many times i bleed, or due vacuum bleed when you subtract syringe with oil to force air from oil, i get inconsistent lever anyway after the bike is like upside down or whatever, what am i missing?

[@bushidooo1]

(shimano xt 8000 here) Did you check that your pistons move equally? Left piston on my rear break was moving very little and did not come out in contrast to the other side. A bit of oil on the side just as Doddy described helped to move it. Than, as my pads aren't new, with the attached and open reservoir, I just made sure the pistons are a bid out so that when I insert the pads they basically slightly touch the disc. If you now close the system withou further leaverstrokes, the amount of oil in the systems stays a bit higher. Now my breakes firstly feel equal front and back, and secondly are snappy as I like them. Maybe this helps

[@rupedog]

Shimanos now infamous 'wandering bite point issue'. Warranty them...tho new one might be same as shimano cant definitively fix it.

[@henriks.1654]

#askGMBNTech Hey Doddy, I want to buy my first decent bike and I'm looking to buy a used bikes and wondering if it's better to buy a newer low budget bike or an old high end bike?

[@rollinrat4850]

Often used high end bikes are used really hard. To get a good deal you must learn to look for all the signs of wear, abuse, neglect and know what that costs as well as all the parts availability issues. A really beat up high end bike that needs a complete overhaul, suspension and pivot service, new drivetrain and brake components and on and on can exceed $1000. Just to get it safe, reliable and rideable. I often tell the people with these sort of bikes it's more cost effective to get a new bike! To get a 'good deal', ALL this needs to be considered and compensated for in the agreed price. Often, with complex bikes over 5 years old, it's more difficult to find obscure parts for pivots, shocks and much more. Bicycles have also gotten much more proprietary in the last several years, so entire systems may need to be replaced because it all works together. These days, production bikes aren't really designed to last more than 5 years of hard riding unless the owner takes excellent care of it, which is pretty rare for hardcore fun-hogs. The market changes too fast and high end riders are often fickle and motivated by marketing BS. I'd say ride what you have and save up or just buy new what you can afford now. Avoid complexity, look at hardtails, singlespeeds etc. Unless of course you know what to look for. I'm a shop mechanic, so I get great deals on high end, yet outdated bikes and parts that serve my purposes. I know exactly what to look for, parts that last long, are repairable or upgradeable. But I prefer very simple bicycles, like rigid MTBs, singlespeeds etc, because there is little to go wrong or maintain. New 'technology' doesn't really impress me. I see and fix all the issues on new stuff and use up all my patience on 'new technology' so I don't want to fix my own. I just want to spend time riding. I can have fun and go fast enough on most anything that fits. Reliability and comfort on long rides is what I seek out. Ive raced, ridden hard and wrenched for almost 50 years so I've been there, done that. Buying used stuff is definately tricky unless you can get it really cheap.

[@psiakrew8367]

#askgmbntech Is there any possibility of setting up a free stroke on Shimano zee levers? I've a problem with my Saint/zee setup new hose,new oil, new rotor, new pads( metal) still lack of power. Next week I'll buy resin pads and will look into pistons if they're not sticky.

[@dylan-5287]

That sounds like more of a pad/rotor issue. Sure it's not contaminated or not bedded in properly? Or possibly a small leak at the piston that's contaminating pads? Those brakes are super powerful.

[@SnootchieBootchies27]

I think Dylan is right. Either you've contaminated your new pads or rotor, or you just haven't broken them in yet

[@rupedog]

Contaminated (did u wear clean latex/nitrile gloves?) And not bedded in. Several vids on gmbn on bedding in. Think neil did one recently.

[@VictorElGreco]

I have an MTB trapped in a house that I haven’t had access to for over a year due to COVID. What should I expect from my hydraulic brakes when I get to ride it again this month?

[@jasonlewis6914]

Not mine. I have the Shimano xtr brakes. They almost have to much stoping power lol

[@jonathanhoare9006]

#doddy I think you meant to say dot fluid is hygroscopic not hydroscopic. Hydroscopic is the ability to see underwater. 😉

[@rupedog]

Very true.... mineral oil is 'nun' hydroscopic too 😋😂

[@balduroreyjolfsson7853]

Awesome video. Thank you so much Doddy :-)

[@matmatteo8238]

#askGMBNTech Hi! I was considering to buy a high end set of 4 pot brakes and I narrowed It down to three options: Hayes dominion, Hope or Formula Cura. I am curious to know which One would be the easiest to do maintenance on, considered I am confident in bleeding brakes, but I am not a professional mechanic. There Is no rush and I'll have to save money for a while, but I am curious to know a bit more about those brands than what you usually find on KZbin reviews. My current set Is Shimano Slx 4 piston. Thanks!

[@rupedog]

Hope...for lifelong serviceability and spares and support...never had them, but thats their reputation. Also did really well in recent mbuk (mbr?) test...better than the others u mentioned on power, price, modulation.

[@mrsmartypants_1]

Kinda disagree with Rupert. Hayes Dominion are the best of the 3. Hopes are excellent however.

[@tigerbalm666]

Tektro uses mineral oil too. I just use food grade mineral oilsince i has a gallon of it..way cheaper!

[@johann9579]

#AskGMBNTech i'm planning on getting a new trail hardtail for this season and I'm thinking about getting a tire insert such as the Vittoria Airliner. In other words - will I still suffer from pinch punctures or damage to the rim, as I haven't tried out tubeless yet? Loving GMBN Tech, Cheers from Germany!

[@mrsmartypants_1]

Go tubeless. I resisted for a year. It’s so much better. I haven’t suffered a single flat since switching plus the tires feel more responsive without the inner tube. Lastly you can put significantly less air pressure in your tires if you’re running steep gnar.

[@johann9579]

@@mrsmartypants_1 and what about the insert (only in the rear)?

[@mrsmartypants_1]

@@johann9579 I have no experience with inserts. As I haven’t gotten flats I’ve found no need for them. I roll with tough casing versions of Maxxis tires (Minion DHR 2’s with Double Down sidewalks on the rear and Minion DHF’s MaxGrip on the front). I ride some pretty sharp rocky steep trails too. I have sustained a couple small punctures that instantly sealed. Lost less than 2 psi of tire pressure. Also I don’t go crazy low on tire pressure like some folks. I don’t like the feel of squirmy sidewalls. Lowest I usually go is 23 psi in the back and 21 in the front. I weigh 185 lbs. If I were you I’d convert to tubeless and see how it goes before buying inserts. But if you do ride super rocky stuff, especially with carbon rims it’s always a good safety measure. I ride alloy rims.

[@johann9579]

@@mrsmartypants_1 Thanks for the excellent advice, mate!

[@fergusoh5092]

#AskGMBNTech how come tubeless sealant doesn't clog up the valve and stop it from letting air in/out as it would a puncture when letting air out of a tyre?

[@harrybryson1130]

It does sometimes

[@aakos26]

It does block it, in some cases it can make you valve core completely stuck.

[@mikechatwood]

How about covering older generation components, my brakes fill from the leaver

[@mrfrogg46able]

get a new bike. you will be doing yourself a great service if you love to ride.

[@johngomez1520]

How about a leaking caliper piston can it be fix.......????😶🤔😶🤔😶🤔

[@neousek_mtb2727]

#AskGMBNTech . Can I reuse Dot oil ?? And if I can. how many times I can reuse the oil ??

[@rupedog]

No...never reuse dot in brakes. It should be fully replaced (not just a bleed) every 1-2 years...same on ur car

[@adliq6307]

My rear brake is like an abs when im braking its like pushing back my finger

[@antoinechalons]

#AskGMBNTech Hi Doddy, I have an XC hardtail with a 180mm rotor at the front and a 160mm rotor at the back (XT 2 pistons calipers front and rear), I'm happy with how it brakes BUT on long alpine descents (1000m drop) they over-heat and the braking power fades, I need to pause a few minutes. What is the best way to takle this? Better pads (with radiator fins), fit-in larger rotors (203 at the front and 180 at the back), 4 piston calipers?

[@mtbboy1993]

I suggest getting bigger rotors, 4 piston or bigger piston brakes. floating rotors help a lot if you want to keep same size, but what you are doing I think bigger rotors might be needed anyway. also make sure the brakes are not leaking and glazing the rotors and overheating the system, cooking the rotors.

[@antoinechalons]

@@mtbboy1993 thks for your suggestion, I've already ordered an offset kit to put a 180mm rotor at the back and I'll use pads with fins

[@mtbboy1993]

@@antoinechalons the fins might make some difference, I don't know if it will fix it. But I did not have good luck with the metallic finned pads, I have been cracking the compound. But resin wears too fast, but semi metallic trp pads did bite as well, but I have mechanical brakes now, but still use the hope floating rotors, but now I have 180 rotor on rear cus my new bike has that as minimum. These pads did well. Don't crack they are the same siz was the cheap shimano low end brakes use. But I am not sure if cooling will be greatly improved with finned pads cus I went from resin pads to finned metallic pads. Bite sure was much better, wear too. But shimano pads are not the best with durability I think. I think it might be gravel killing the pads.

[@antoinechalons]

@@mtbboy1993 I've recently fitted AMP Carbone/Organic, they're meant to improve heat evacuation, in addition i've ordered a pair of Neatt pads, the reason for this is the actual pad is separated from the dadiator fins, so the fins can be re-used wit other pads www.alltricks.fr/F-11934-plaquettes-de-frein/P-186444-paire_de_plaquettes_ventilees_neatt_pour_shimano_xtr___xt___slx___deore

[@mtbboy1993]

@@antoinechalons seems like a smart idea.

[@1jwh1]

I’m a believer in not over cleaning especially the brakes. The oil in the system should lubricate the seals. add in someone who uses disc brake cleaner/GT/WD product’s spraying into the calipers and wonders why they squeal ,drying out the seals in the process. the brake surfaces need to be oil free, not squeaky clean, the brake cleaner evaporates taking the good lubricant and grippy brake dust particles with it. Avid/sram are like a lottery difference is I’d rather waste money on the lottery, With Shimano you get a regular result after a bleed. Although shimano went through a patch of dodgy pistons and seals a while back. If your brake is contaminated,figure out where the oil has come from,sort it bin old pads replace along with the rotor. brake cleaner will not decontaminate pads but give the rotor a good scrub with hot soapy water and nail brush will get the rotor useable again if not too worn out.

[@kieran710]

#doddy gmbn i had a bike new last year and the brakes dont quite feel the same any more as when new, pads have gone down but not worn out would it be this, or shall i do a mini bleed ? They still work just not as much bite/ stopping power ?

[@The_Dude_420]

If they are: Shimano -> Pads Sram -> Bleed Magura -> They will always have bite 😂 I ride brakes of all 3 manufacturers

[@kieran710]

@@The_Dude_420 thanks mate 👍🏼 shimano i got some new pads aswell so will prob change them soon then. As i said they still work just not as good as they did didnt think i needed to do a bleed yet and that it was just the pads wearing down would that be right ?

[@The_Dude_420]

@@kieran710 That should be right! I was kinda joking, but there is some truth behind it. In my experience mineral oil which is used by Shimano and Magura doesn't need to be bleeded that fast. I only did it after 2 years (Shimano) because I thought I have to, the brakes were still feeling pretty fine. So yeah it should be the pads and even if not having them as spare won't be bad! Another trick that can make them feel a bit better: Zip tie the lever over night, with the lever being the highest point of the system. Last but not least you can adjust the reach to be bigger, the increased leverage can give you a more bitey feeling imo.

[@kieran710]

@@The_Dude_420 cheers dude🤙🏼

[@The_Dude_420]

@@kieran710 You are welcome mate, hope it helps 🤘🏽

[@syntrax-og]

#AskGMBNTech Is there an engineering reason on to why 4 pistons calipers never actually evenly? I thought that with your SRAM & Shimano connections might have explained you why. Does the same thing happen in car's pistons?

[@rupedog]

They often have different sized pistons in the front v rear pistons of the 4 pot, to effectively 'toe in' the pads. Same reason u should toe in rim brakes, the movement pulls them forward. So the front 2 pistons of a 4 pot are usually bigger

[@danielgough4496]

#AskGMBNTech Can you use non tubeless rims on a tubeless system?

[@daylightsensor8695]

yes, you just need to tape your rims

[@jasonrusch]

#askgmbntech If tubeless sealant is able to seal a hole when it leaks through and is exposed to air, why doesn't it harden from all the air already in my tube?

[@viethknorr5389]

It's because tubeless sealant has tiny little "things" in it to blockade the hole. Seth bike hacks/berm peak had made a Video where he put glitter into the sealant to support the blockade effect

[@rupedog]

@@viethknorr5389 not so...those help seal, they are not essential, many dont have particles.

[@rupedog]

It does....sealant dries out over time to form sealant boggies/boogers! But the pressurised escape from the tyre causes sealing action as its forced through the tiny hole. So bigger holes, much harder to seal

[@jasonrusch]

@@rupedog ahhhh. Thanks so much for responding! I really appreciate it.

[@rourkeyliiid4769]

Take a shot every time doddy says system.

[@johnbuxton3841]

I seem to remember on an earlier maintenance video that silicon grease can be used to lubricate brake pistons (sparingly).Is this so, or advisable.

[@rupedog]

NO. Never use silicone, copper slip or any grease on pistons. It can swell seals. It also attracts dirt, making issue worse, and scoring seals and pistons. If DOT brakes, it contaminates the fluid to. You can service sram calipers, and you buy specialist DOT grease fir the caliper body seals, but even then NOT the piston seals/pistons. As doddy said, ONLY the brake fluid, and then once pistons full retracted again, clean with brake cleaner to remove residue.

[@johnbuxton3841]

@@rupedog Thank you very much for the info'. Happily so far, I have never had the problem.

[@johnbuxton3841]

@@rupedog Thank you for the info.

[@joaoafonso1178]

#AskGMBNTech Hi Doddy. I got a brake selection question. I've bought a used Yeti SB66 and the last owner used Formula R1 levers with Hope Mono Mini calipers. I took the bike to a shop and there they said that this mixing will eventually lead to poor braking... Now the rear brake is feeling really soft and bleeding it doesn't really help. My question is, since the components are good, should I keep the levers and buy a caliper from Formula (if yes, does a new R1 caliper fits just fine?), or should I get a Hope lever, or last case, should I buy a new complete set? Thanks for all the videos, I love them and they teach so much! Cheers from Portugal

[@mtbboy1993]

both use DOT fluid so should not be an issue, they probably just need a bleed, but seals might be leaking and letting air it, if so swap those, you can get spares, as it's Formula and Hope, they offer these parts as spares. but this is the first time I hear about this set up.

[@joaoafonso1178]

@@mtbboy1993 thanks for the advice, I'll try the new seals ;), but I have another question: the rear rotor is quite worn down. If I want to replace it, is it mandatory to use Hope rotors or any quality floating rotor will do?

[@mtbboy1993]

@@joaoafonso1178 any other quality rotor will do, I just knew these would be decent, and was easy and fast to get those for me at the time. I know there are more good rotors, Brakestuff looks interesting, but they dont do floating rotors, but they offer rotors with smaller venting holes and thicker rotors which is interesting. Magura also has rotors but not as easy to get. I see Clarks is a popular option for low budget builds, but not tried them. Shimano Ice tech rotors seem to scream, so do Sram Centerline, but some people don't have these issues so I am not sure where the issue is coming from. pad and rotor combo maybe, I don't know, maybe the big venting holes, maybe something that gets on the rotors, I don't know but seen it on video people riding in American dry conditions and brakes screaming. I've not tried them, but cat fight sounds are not nice when braking. Hope is nice but as with all floating rotors the rivets will eventually be creaky after years of use. TRP seems to be easy to get. they seem to be decent.

[@mtbboy1993]

@@joaoafonso1178 the Magura E rotors look interesting,

[@mtbboy1993]

@@joaoafonso1178 Galfer rotors and brake pads has come highly recommended, but I've not tried them. Also Trickstuff pads and rotors. I know Formula has brake rotors too, both regular and floating, I don't know much about their performance. I know TRP offers thicker rotors for E bikes and enduro, downhill riding. but thick rotors is nothing new, Brakestuff had it for decades. but thick rotors require calipers that support it. Hope also did vented floating rotors, so that's basically two discs with a gap in the middle for cooling, they are very heavy. a complaint with these is they collect sand and wear the pads faster and make noise. I've not tried them.