Snapped Carbon Frames, Correct Tyre Pressure & Indoor Trainer Lube | GCN Tech Clinic

[@gcntech]

If the super nerds couldn't answer your tech related questions within the allotted time, fret not! Be persistent and use #askgcntech when asking your questions! 👇

[@jameswalker1759]

#askgcntech I have recently purchased a set of Hunt 4 Season wheels with rim brakes, I fitted theses with latex tubes. After flicking through the manufacturers documentation, there is a WARNING not to fit latex tubes. When I asked the manufacturer 'why?', they said this was due to the potential for heat build-up in the brake track which could then cause the tube to burst. Have you ever heard of latex tubes bursting due to heat exposure and why are latex more susceptible than other materials?

[@farizrd]

Hi guys, I recently upgraded the wheelset on my entry level rim brake bike. The new wheels are custom build by local bike shop. It has 20h with radial pattern on front wheel, while rear wheel has 24h hybrid pattern - 2 cross interlaced on drive side and radial on non drive side. I have ridden the new wheels for 400 km with no issue but I found out that many other rear wheels out there with 24h spokes has 2 cross pattern on both sides or even 3 cross. Should I change the pattern on my rear wheel? Whats the benefit for each lacing pattern? Thanks in advance. #AskGCNtech

[@marco_espejo]

I love watching Alex who is so meticulous and particular in his bike maintenance and/or setup choices, giving advice alongside Mr WD40 Richardson. 😂

[@LUCYDIAMONDBOXER1]

Ive actually just caused a crack in my chainstay this week on my TCR which has been on my Kickr for last 3 yrs. Going to attempt a carbon fix with a kit ive just bought

[@a1white]

11:07 for the last one. Definitely new pads. When I got my bike the stock pads that came on the rim brakes were awful and made a terrible scraping sound when braking. Swisstop pads are good.

[@bikeanddogtripsvirtualcycling]

Thanks for the indoor trainer carbon reply guys. My mission in life is to now try and produce enough power to rip out the bb😂😂

[@markusseppala6547]

Also consider a rocker plate

[@christophermanson6754]

Onlympic distance tri - My old metal wheel had a pincture woth 15km left. Finished the race and just replaced the puncture after the race. Rim still going strong. I rode it easy that last 15 km though.

[@wuzihuzi]

I raced today and ran new tyres. Woops!

[@gcntech]

What’s the damage count?

[@JeffreyWilliams-dr7qe]

Whereabouts? Really want to know!

[@bikeanddogtripsvirtualcycling]

I raced yesterday and ran out of lung capacity and enough heart beats per minute

[@JeffreyWilliams-dr7qe]

@bikeanddogtripsvirtualcycling See if you can find some Cytomax. Expired is OK! Thanks!

[@SteakandChains]

You guys need to watch the Silka and zero friction cycling stance on waxed chains and corrosion. In their experience, wax is absolutely much better than drip for the long term health of your drivetrain and will improve corrosion resistance

[@olishobbyscene1643]

for the carbon frame topic I always would check with the manufacturer, as some might have limitations given here to use their frames on indoor trainer. My Canyon Endurace is good for a smart trainer though acc. Canyon.

[@davidowen6639]

As a very average cyclist I can assure you it’s possible to snap a chain stay on a trainer. That’s if you don’t have the quick release tight enough, stand up to put some power down and you and bike keel over. The force of that snapped the chain stay on my SuperSix EVO HiMod. It was repaired like new by Carbon Reincarnation. Fortunately no injury to me from the fall.

[@newhorizons.english]

#askgcntech Hello Humprhey and Willard. I've recently gone from 172.5 to 167.5 cranks. I feel like they're better for spinning on the flat but not as good uphill. I theorise it's because of the shorter leverage. I hear a lot about advantages but I'm pretty sure there are disadvantages. Anyway, do you guys have any toughts on the disadvantages of shorter cranks, say 170 and shorter?

[@spardamustdie47]

This is related to the first question, my brother's bike frame actually cracked on the seat tube (just above the seat stays) on his Cipollini N1k1 frame while riding on a bike trainer. It was a couple of years back during lockdown, where indoor training was the only option at that time. Luckily the bike frame was still under warranty, got his replacement frame for free. But yeah, I've seen carbon frame cracked on a bike trainer

[@poststuff2]

I use a waxed chain on my indoor trainer and place a towel down under the drive train and it collects any wax droppings, then wash the towel when finished. Job done.

[@tysonmou1]

Just last week, my Cannondale supersix six tiagra snapped almost all the way through in the middle of the left seat stay. Only a few fibres remain holding it together. It's a permanent trainer bike, I had it on a DIY rocker plate type thing. It wasn't because I put so much power into the bike, but rather it was likely because I'm heavy at 105kg. And a car crash 9 years ago probably left micro-cracks that manifested over the years.

[@rogerheatwole4103]

I have an indoor chain and cassette and use Silca Synergetic lub. I use Silca Hotmelt on my outdoor chains.

[@joelcohen4353]

I haven't ripped anything out, but the BB on my training bike has needed servicing every two years or so (about 6,000 miles/year). Using it on the trainer is hard on the drivetrain and BB components, requiring as much maintenance as a regular road bike.

[@MggW]

Regarding waxing your chain on your turbo, simply have a mat under the bike and vacuum up the wax "dandruff". The wax coats the chain so should prevent corrosion, as it does outside. Oiling a chain is a total loss lubrication system, and so the chain will be dropping oil even if you can't see it.

[@barryaronson9697]

Regarding saddle bags, although this may be of small impact, I thought that having unrestricted airflow just under the saddle (between the rails and above the seatpost clamp) was important because air was funneled in there by one's legs. Therefore, although probably of small impact, a saddlebag adds aerodynamic drag.

[@yogatriathlete]

I'm so happy to hear Si say you run lower pressures than the Silca calculator. Personally I think that calculator is due for an update. Pressures for wide tubless tires on hookless rims are especially too high according to their recommendations.

[@elindred]

#askgcntech I bought some light and compact TPU inner tubes to carry on my commuter bike in case of a puncture. But I didn't take into account that my current tubes have Schrater valves whereas the tpu tubes are presta. My mini pump has fittings for both, but can I use presta tubes in my schrater rims?

[@maks3.5k40]

you can use them

[@nickkambitis5340]

Should still use wax. Wax isn’t just about stopping dirt entering the pins inside the chain, it’s about friction as well. A wax chain longevity is the same indoors as in outdoors. Initially just put some paper on the floor, once the chain stops depositing loose wax, lift the paper and dispose. I’m also guessing you’re putting something on the floor to mop up sweat? And old towel could collect the wax. Shake off outside afterwards. Wet/ dry lube = grinding paste indoors or out.

[@grumbazor]

8:00 if you aorry about the resistance of a saddle bad why not ride a recumbet bike? Or a velomobil? Its much faster than a normal bike and you can carrs whole suitcases and will still be faster every other bike. If you want to improve your speed, dont waste time on saddle bikes, just get another bike with less air resistance

[@scopie49]

Because the people worried about watts will be racing where recumbents aren't allowed so there's no point in training on one.

[@dannyheyrman4848]

@@scopie49 i doubt that. i rode a recumbent bike as a commuter for 1 year. you need a different, more fluid, pedalling style and i can hold a cadance of 100 for a couple of hours now where i couldn't hold 80 before that.

[@scopie49]

@@dannyheyrman4848 There's no guarantee you wouldn't have made the same progress on a regular bike. But the real point is that if you're racing on a normal bike you need to train on one. One is bike fit and finding a specific fit that works so you don't get hurt, hands don't go numb, neck doesn't crane upward, etc. Getting used to being hunched over the bars and honestly just sitting in the saddle for hours is important. Or how about cornering when your center of gravity is higher off the ground? You'll still gain cardio through recumbent but there are a lot of reasons you'd want to train on a regular bike. You need confidence in being upright.

[@dannyheyrman4848]

@ agree, but you don’t have to do all the training on the recombrent. I just said said you can train on cadence as it is really important on a recumbent bike. And I race cv marathon, but 80% of my training is on a road bike. And I go to the gym for core training. All these different things add up and benefits my mtb riding and racing.

[@scopie49]

@@dannyheyrman4848 I mean yeah. You can cross train and do different things. My main argument was against the OP specifically for people who care about watts saved and aerodynamics. Setting a PB on a recumbent doesn't really mean anything if you're racing with normal bikes. They're two different classes of vehicle. It's not ideal to train solely on a recumbent for the watts, i.e., good numbers, when your biking form on a regular bike would be more important. It's the second time I've seen someone comment on, "Why not just use a recumbent if you care about aerodynamics or watts?" The same argument could literally be, "Why not just buy an e-bike if you care about watts?" Point is you can't use those in a race.

[@Bobby-wn5yr]

I had a 2012 cannondale that went on a trainer after 7 years of use during Covid. Over 2 years of indoor trainer I did notice the carbon frame was flexing noticeably more than it had been at the start. I think the trainer caused it to flex more and age faster than it would have in road use, but it also got a lot of use over a lot of years and didn’t fail

[@PNWmtnBKR]

Using a rocker plate makes a massive difference on how much force you put into the frame. It’s a heck of a lot more comfortable too.

[@McLovin38FFs]

Dear Rupert, Sir Ollie and the GCN team. I have two bikes, one with Ultegra mechanical, the other with 105 (gsotp) di2. My question is are all quick links made equal? Do I have to buy two different types/sizes for the different group sets? TIA

[@irfuel]

If both are the same number of gears (e.g. 12 speed or 11 speed), the chains and quicklinks are the same.

[@McLovin38FFs]

The Ultegra is 11 speed and the 105 is 12 speed.

[@smithpauld1501]

I use Silca’s drip wax when I start to hear the chain. No dandruff that I can see.

[@emmabird9745]

Guys, bum fairngs aren't new. They appeared in the 1920s, balsa strips and tissue with a pair of thin support struts from the rear axle and they looked like the back of a Zepplin (remember those). They were so effective that avaerage riders were quicker that the champs without. The UCI banned them (what a surprise). But the UCI has no juristiction here!

[@larrylem3582]

And GCN already made fun of the inflatable backpack fairing a couple of months ago.

[@robertholmes5370]

just a suggestion recently seen a road you may want to try riding. Snail road in Chile. hopefully going next year.

[@bikecommuter24]

scrapping sound if it just from wheel front or back swap the pads and see if the sound moves from one end to the other, also one of the rims could have a burr or bump in it or the rim could be out of round a tad, easy enough to check. I once had a weird sound come from my rear wheel, it made a noise when I applied the brake, I stopped to see the problem, it was a flat tire and right at the last 16km of a 76 km ride.

[@JimKJeffries]

With 90lbs of bike weight, my rear rim brakes would often glaze. Then the squaked like geese upset. Lava soap in bar form (pumice soap). Scrub the pad, rinse, repeat: until as new. No squeaks or squacks. Not certain but would Hazzard the guess, that I over heat them, and it happens. Remember, clean that rim too. Ride more. Know your/you're love

[@MggW]

An entire tech show with Si and not one mention of WD40!

[@BarePotato]

#askgcntech My road bike got steering feel like indexed. I think head bearing need replacement? Both upper and lower sides?

[@awesomexistence]

As a safety issue Definitely replace the headset. Indexed bearings put me In a high speed shimmy loss of control on a mountain descent. This was on a new bike with 5 rides. The headset had been improperly installed.

[@sbccbc7471]

Your headset bearings are worn till they've developed pitting, giving the indexed feel. Replace immediately.

[@michaelpeppersack8599]

I have a tire question about storing my gp 5000 that I bought in advance to be ready when I needed it! how should I store it so it doesn't rot and its ready in advance?

[@caillou450]

#askgcntech. Hi guys. Mystery here! My two tyres, Schwabe Pro One 30mm with TPU tubes, keep on deflating in a seemingly random pattern! Never know when will one be flat from one day to the other. And sometimes, they both keep their pressure for days on! I just don’t understand what could be the root cause of this. Valves, maybe? Do tyres have an attitude!? Hope I grab your attention. Thx for your help.

[@ralphc1405]

Maybe your rim tape is not covering the one (or several) rim eyelets? INSPECT THE RIM TAPE PATH MAKING SURE IT COVERS THE SPOKE EYELETS. The tube can come in contact with just a fraction of the metal causing it to have a pin-hole size puncture causing a slow leak.

[@sallyviewville8944]

Does specialized cover indoor training on carbon bikes?

[@greg_mid_tn3150]

#askgcntech Hi Guys! I converted my gravel bike to SRAM GX1. I love the 1x system, but when in the lowest gear and 250+ watts, I'm getting a loud noise and vibration from the rear mech (or chain?). I've checked the B limit and it looks right. Could it be the chainline or maybe the chain is too short? I don't get the noise in 12th gear at same power. Very frustrating when climbingn hills. Thanks!

[@Cherokee140Driver]

I'm on a budget hybrid bike running 622x20 mm rims with tubes. My tires are currently 700x40c but I want to push that up to 45-50c. Can I run that size tire with a tube on my 20 mm rims? I'm also assuming that if it's possible I'll need larger tube as well.

[@denniskinyua7164]

20 mm internal width?

[@Cherokee140Driver]

@@denniskinyua7164 I'm assuming so. The rim itself is labeled 622x20.

[@khazza930]

#askgcntech Hi everyone! I started noticing some mould building up inside nozzle of my water bottle. It's inside the nozzle, and there's no way for me to get to it with a brush to clean it. Is there a way to clean it? It's a nice bottle that i'd hate to have to throw away.

[@pandatactical4530]

Bleach

[@grumbazor]

Only fill bottles with clean, pure water. Any other liquid will mess it up. I used to put some apple juice into my water and it turned my bottles into a biolab. To clean it, just throw it into a dishwasher at high temp.

[@bikeanddogtripsvirtualcycling]

you can buy sanitizer tablets. rinse your bottle out first, then take the nozzle apart of possible and then just add everything to a bowl of hot water with the santizer tablet / water overnight. You can also buy very thin nozzle cleaning brushes to remove the dislodged crap after the previous soaking

[@benconnor4848]

Under a trainer, get a large rubber (or similar) mat to go under the trainer. I got mine, a 4ft by 8ft rubberized mat, at Home Depot. It’ll protect your floor from bike dandruff and sweat

[@TonyDubo]

If you're riding a gravel bike in the snow at -2 to -5°C, what type of lubricant should you use?

[@OriginalTrev]

Riding in western Alberta Canada, I immersive wax my chain every 400km for all weather conditions in temperatures from -30C to 35C... those temps are the limits of my body and not the wax

[@TonyDubo]

@@OriginalTrev Thanks

[@DubMasterFish]

Really! I saw waxing for indoor riding as a pro not a con. Just vacuum around the bike!

[@pandatactical4530]

Just use a rubber mat

[@JimUe1]

just lay down a page of newspaper

[@pandatactical4530]

@ Not if you have a fan

[@ArnMartBelgo]

Same for me, rubber mat works perfectly

[@dansheremeto4073]

I think the bigger and hidden issue is all of the wax particles that find their way inside the trainer. Given long enough exposure, this will absolutely gum up the mechanics, which are extraordinarily difficult to clean. I used to use wax on my indoor trainer bike, and switched back to a dry lube for this very reason.

[@shahahahahjack3299]

Hello, I just want to get recommendation from the community, I want to get my first gravel bike and planning to have just that one as my forever bike. Any recommendation? I would like to also have a bike that is capable of upgrading its parts.

[@dperreno]

I just saw a video by Josh at Silca recommending mixing some of their Synergetic wet lube into their wax for use in wet weather. Actually, if I wonder if you could just add some Synergetic to an already waxed chain to "smooth it out" and reduce the amount of wax particles that get flung everywhere. If you are starting with a clean chain, then maybe using the Super Secret Liquid lube would be less messy. My trainer bike this year is using PTFE lube so I'm not going to be experimenting with any of that for y'all, sorry! I can notice the difference between having my saddle bag and no saddle bag, but only because it adds some weight at the saddle. I notice it when riding out of the saddle, but there is no difference when going downhill, for example. The guy with the scraping sound from his rim brakes - replace your pads!

[@凸Bebo凸]

Not a big saddle bag fan as I tend to stand up pedal a lot. When you stand up pedal the saddle bag becomes like a pendulum making the side to side motion of the bike way less pleasant. I'd way rather carry that stuff in the second bottle cage.

[@tomasztomaszewski9275]

I’m doing 1400+ Wat standing sprints and everything works fine. Trainer jumps up and moves all over the room. No damage at all. For years 😀

[@forza1860muc]

Yeah it‘s almost as if the bikes and trainers were built for this purpose 😮

[@JimUe1]

i do 1401+ watt standing sprints, rocking the bike & trainer left & right, inches off the floor with each crank revolution on a 10+ year old carbon frame. no damage at all. none.

[@KelvinSuddith]

Can I ask what trainer you use? I’ve got an old Kurt Kinetic and a newer TCR, and finding a thru-axle that works in the Kinetic is rough

[@better.better]

do I hear140*2* ​...1402? going once... going twice....SOLD!

[@wd678]

Flexing 😂

[@RonohRonohRonoh]

Hey gang, I live in a small apartment in London, and my girlfriend won’t allow me to store my bikes inside over winter (fair enough…). However, we do have a balcony. Is it okay to keep my bikes covered on the balcony throughout the winter months? Would additional layers over the bikes minimise potential issues? Thanks! #askgcntech

[@GregLanz]

I'd much rather clean up some dry wax flakes than wet oil especially out of a carpet. But also why I don't have any carpet in my house, the stuff is nasty

[@hutchy_4297]

Hardwoods ftw. Who puts the trainer directly on a carpet anyway haha:p

[@smithandshortdogs]

Why was the last questioner putting beer on their brakes? Is it Dan under a pseudonym trying to find a use for his remaining stash now he is teetotal?

[@DavidFritzIII]

The cycling rolling resistance Website tested the new vs old and found exactly what was said... literally zero difference in rolling resistance after nearly 1-2mm of tread wear. Puncture protection wasn't very different but slightly worse

[@Jari1973]

#askgcntech Which is faster on tires on flat.. hard rubber compound or soft rubber compound?

[@ReportReport-fz2pn]

Sidewall supple-ness probably makes more of a difference. So presume softer compound too. Try the René Herse website for their take on the subject.

[@Jari1973]

@@ReportReport-fz2pn 👍

[@greggsenne1268]

Cleaning brake pads with sandpaper is not a good idea. Some of the abrasive from the sandpaper can come loose and embed itself in the pad. Better to give the pad a light scrape with a utility knife blade or something similar. Riding on wet roads can also cause your pads to pick up grit. Check your pads after a wet ride.

[@hutchy_4297]

I was wondering the same thing but I wasn't sure. I say just buy new pads but I'm lazy haha

[@samuelsloth6730]

A metal file works fine Sand paper only for disc pads

[@lechprotean]

I can max around 1200W for a couple of seconds no issues for years

[@petersmith9470]

Carbon is a woven material and is immensely strong but it if gets a knick in the weave it becomes pretty fragile and weaken the strength immensely.

[@payneridesbikes]

Way to miss a sponsor plug... silca recommends using the e bike synergetic lube on the trainer!!!

[@petergoebelsmann4631]

There is a special wax for indoor trainers available from Dynamics which I can recommend

[@mommamooney]

Husband has launched his bike off the trainer on a sprint. Twice. He has an old school bike without a through axle. Fortunately he’s right next to the guest bed and has a soft landing

[@overcookit1433]

@shamendra.sakthivel: Cleaning the brake pads is just one half of the job, you also have to clean the rim with a special cleaning rubber for alloy rims offered from Mavic and Swissstop. This has to be done after rides in the rain and also after putting in new brake pads. Cleaning the brake surface with IPA is nonsense, that does only help the manufacturer of that stuff. And also use proper brake pads as Swissstop Flash Pro original black and no standard crap, as standard brake pads (no matter whether they are from Shimano or Noname) contain small partikels to enhance the braking power, but they wear out alloy rims rather quickly, wereas the mentioned Swissstop brake pads only contain rubber.

[@Doniyorbek_Turgunov]

#askgcntech. My father owns a bee yard. Can I use a beewax for waxing a chain? Never tried before, but want to try during a waxing-hype-era ;)

[@kp5833]

I cracked my BH road bike on my trainer . I stood up and rode it hard and I heard a crack noise and sure enough it cracked

[@better.better]

"oh, I've found your problem: you're using rim brakes!"

[@PoulHansenDK]

No matter what. I will avoid all those used bikes where the seller proudly announces: "Only used indoors". Its not a matter of BB but the whole frame not being designed to flex around the rear hub. And most frames being carbon that steadily deteriorates with every force it is subjected to. Just imagine the rearstays when a 90kg brute is sprinting with 1.500W and the hub is fixed.😱😱

[@凸Bebo凸]

Best indoor trainer lube is Chain L from America. Makes the bike silent and lasts 2000km. Basically the heaviest mineral oil possible is the best lube, especially if you are running a chain cover indoors since there isn't going to be dirt getting on the chain. If you can't get Chain L in your country, Phil's Tenacious Oil is an ok substitute but doesn't have the same high pressure stabilizers and won't last as long.

[@DDSPL15]

Waxed chain for indoor trainer is nice if you have stupid pets who constantly like to rub their fur against your drive train. Regarding wax flakes, I just put down a yoga mat under the trainer & vacuum the flakes up after swapping in a new chain.

[@Ukfamine2025]

Put your trainer on some old newspapers to collect the wax. You can reuse the wax and stop the environment from dying. 😂😂😂

[@smithpauld1501]

Ooooh! I like! Now Silca will sell a $250 wax catcher.

[@Ukfamine2025]

@smithpauld1501 🤣🤣🤣

[@Fortnited272]

Ceramicspeed is making the indoor wax that doesn't cause any mess ...

[@xosece]

#askgcntech how do you think is that I am beating all my Strava best times with a fitness hybrid bike compared to my road bike with which I had my best times before? I got a Pathlite 6 (40mm stock Shwalbe G-One Bite tyres 2022 model) which is 1X 36T 10-51T 12 gears with locked FS and a 2X 48/34T 11-34T road bike and I'm beating all my best times on the fitness bike without even trying! I am amateur, 1,81m tall and weigh 80Kg. The road bike has 28mm tyres and butyl tubes and weighs 11.6Kg, while I recently put TPU tubes to the hybrid bike and it weighs 12.7Kg stock. I use Silca or SRAM calc for the recommended pressure. My theories vary, but the road bike is allegedly much faster. I live in a very hilly region, you are either going up or down, the tarmac can be a bit cracked in some places, and I think maybe the 1T makes it easier to manage gears? Or maybe the easier gears on hills make me ride less fatigued? On paper 48-11T from the road bike vs 36-10T should make the road bike much faster, but it doesn't seem to work for me that way. I am puzzled.

[@robertcatuara5118]

Rouvy is the new sponsor and your first question is Rouvy? What are the odds?🤦‍♂️

[@runeboa]

Ceramic Speed make a special UFO lube dedicated to indoor trainers

[@hill160881]

I produce 1700-1800 watts. I get pretty violent and have never broken a carbon frame.

[@drspyqwerty]

For indoor pets: waxed chain

[@TESTA-CC]

its easier to snap a carbon frame with an indoor trainer. The rear stays are taking all the abuse and tension under weight which is stationary putting constant force only on the rear stays. If the indoor trainer rocks/lifts off the floor with pure power out put, the frame is lifting the indoor trainer on its rear stays whilst putting power down it will snap a rear stay.

[@Jessy-z1j]

Hello 👋 brother can I get one bicycle brother

[@a1white]

Crikey. I would never dream of riding on a completely flat tyre 😬

[@galenkehler]

You shouldn't be sprinting faster than you have control. Train the technique FIRST so you aren't wasting effort on lateral movement.

[@allenharmon5544]

Don't sand rim brake pads! You will embed abrasive in the soft pad, defeating your objective

[@Andy_ATB]

Some people are taking it too seriously; why worry about whether a saddle bag loses you a few watts? Really? Get a life.....

[@ltu42]

BZZT, wrong! Wet lube will turn into black mess purely due to metal particles forming due to friction. I would accept bike dandruf, use a mat under the trainer and vacuum it up before stowing the bike away.

[@JoeyMills-y3v]

Its hilarious that people are using fancy frames & worrying about the chain on a device that goes nowhere & remains indoors. Cyclists have zero brains 😂

[@svenlima]

Dry lube: Silicon spray

[@grumbazor]

Ballistol!

[@raulmarquez5485]

The advantage of steel rims; I’ve ridden miles on flats. I sure wouldn’t do that with a carbon rim!