Deflating Tyres, Carbon Components & Cycling Clothes | GCN Tech Clinic

[@gcntech]

How do you like your cycling kit to fit? 🚲

[@CarnivoreDMD]

Castelli like fit

[@jamesmckenzie3532]

Snug but not constricting. Castelli got really tight this time around so I'll be ordering one size larger.

[@CarnivoreDMD]

Maybe a GCN SPORTFUL KIT for the masses?

[@feedbackzaloop]

You might have gone for better materials, but the design and cut are a let down

[@zedddddful]

​@@CarnivoreDMD same all my kit is castelli I've been really happy with it their winter gear is impeccable.

[@allenharmon5544]

A word of caution if sanding off clearcoat to remove a decal - if the abrasive contacts the basecoat, the basecoat will be marred permanently. New layer of clearcoat may help hide the damage, but it's unlikely. Projects like this are prone to the mushroom effect: replacing a decal turns into a full frame refinish 🙂

[@gcntech]

Love this! Super cool to see people sharing tips and advice 🙌This is what the Tech Clinic is all about!

[@DavidFritzIII]

Literally every project I ever start turns into a mushroom project... in my head.. while im here I'll just do this one little thing and then this other and the oh yeah if I order this then I can do that too... 1000 Euro later and 20 hours into my 15 min project I have a much more expensive but nice bike that makes me smile just a little more while im riding around at too slow a pace for any of that to have mattered anyway

[@kangzta1]

#askgcntech You guys are legends. Thank you. 🙏❤️ I'll be back for the bike vault! I'll make you proud!

[@DavidFritzIII]

Antone! What are you saying, dont drill holes in your wheels! The ones that are drilled that way in the factory are actually designed with this in mind so the carbon layup should be made comsidering the elevated stress concentrations around the hole. If you drill in an area with too little material/layers, or maybe with primarily unidirectional layups you could risk the wheel failing.

[@miguelpaul1164]

If GCN kit were white with white or light grey cycling shorts , the channel would get more views.

[@geoffdavies1199]

You keep giving me more reasons not to go tubeless or carbon! Happy with my old school steel bikes. Oh and my cheap alloy frame has painted logos not stickers so that's another thing I don't worry about.

[@___Bebo___]

lol watching these videos with people with water in their carbon wheels and air leaking out overnight sure makes it easy not to pull the trigger on "upgrades."

[@gcntech]

Do what makes you happy, that's the great thing about cycling 🙌

[@edmundhodgson2572]

A good one this week guys.x

[@BreakawayB]

You said *”i”* five times, and now I want a 5iiiii power meter.😂

[@jamesmckenzie3532]

If your tubeless tyres are constantly deflating, spray a soap solution around the rim as well. There's a possibility that the tyre didn't seat properly and there's one or more leaks. The solution is to inflate to the maximum rated pressure on the tyre or rim and then bounce it around the circumference of the tyre until it makes a series of popping sounds. If the leak is around the valve STEM, not the core, you can carefully remove the lockring and place a properly sized o-ring on the stem and then hand tighten the lock ring. If it still leaks, it's time to visit your local bicycle shop for a rim inspection.

[@gcntech]

We love this! This is what tech clinic is all about - sharing ideas and progressing our skills 🙌

[@mikemelbrooks]

They were talking about tubular not tubeless.

[@jamesmckenzie3532]

​@@mikemelbrooksThe title is "Why are my tubeless tyres constantly deflating" and they referred to a tyre brand that doesn't make tubulars. Plus I've been a victim of the misseated stem and my LBS fixed it.

[@jwicher68]

Also for the power meter issue - if u have not done so check for a firmware update

[@MiddleAgedMike]

Always a good first step when troubleshooting

[@davidheathfield5040]

I’ve always found that crank/pedal based power reads slightly higher than hub and turbo trainer meters. I thought this was due to power losses throughout the system leading to lower readings the further down the chain you go. My power meters still read a good 10-20 watts higher at the pedal and crank than my Tacx Neo.

[@michaelpippin1957]

My Zipp 404 Firecrests from 2022 have drainage holes

[@kevinbays3408]

What are the effects on tubeless tyre sealant in cold and sub freezing conditions and what do I need to look out for?

[@songfta]

With measurement of power typically you get the most accurate readings closest to where the power is generated - so pedals and cranks tend to be more accurate than a hub-based measurement, which is where a smart trainer gets its data. That said: if the crank-based power meter isn't properly calibrated that is the proverbial spanner in the works. I like the suggestion of testing vis-a-vis another smart trainer. Another option would be to compare against another single-sided crank-based meter or against power pedals (e.g. Favero Assioma, Garmin Rally, or Wahoo Speedplay power pedals) with a known power reading and see where they outliers are. Folks like DC Rainmaker and GP Lama do a lot of comparison between the various ways of measuring power and are good places to do research.

[@janeblogs324]

Hubs are accurate, they just remove the power lost when the chain stays and axle flex. Its more accurate but people are obsessed with higher numbers instead of accuracy

[@sandiegocyclingnutz]

With regards to the drain holes. My brand new 303s front wheel had a hole and rear wheel did not. Ended up going through LBS to send it back and have hole drilled.

[@gcntech]

Great to hear that this is an option 🙌

[@joesmith9709]

When using your bicycle on a smart indoor trainer, I think those who have a bicycle with a power meter should pair the power meter on their bike with the training software they use (Zwift etc). Sure it may or may not be as accurate, however, once you get back outside and on your bike, it's the power meter on your bike that will be used. Therefore, there will be some consistency.

[@jalakere]

My power meter pedals are rated to +-1% while my zwift hub is rated +-2.5% and the tacx bushido wheel on trainer i was using before was +-5%. Kind of feels like a no brainer to use the pedal power meter

[@CR4PM4GG0T]

#askgcntech Ey up. Can I stuff a standard road 700c butyl inner tube into a 650b tyre (47mm in my case, tubeless obvs) in a roadside emergency? Or must I drag around a bulky 650b-specific tube on my adventures

[@johnmorrissey41]

My 4iiii LH powermeter was showing strange peaks.Their customer service was great. They replaced it with no quibbles. It was showing peaks of over 1000 Watts.

[@Bike4Coffee-Cake]

My 4iiii LH power meter gave some funny readings when I first got it, including some very high spikes (>1200W). I removed the battery, checked the contact points and put it back in, and it has been faultless ever since. If I ride on the Wahoo Kickr using Kickr Power on Zwift and the 4iiii on my Garmin head unit they are pretty similar numbers.

[@maartends6051]

@@Bike4Coffee-Cake i have had the same problem it was after a wet ride (not sure because of it) could also have been from travelling constant 1000+ watt. I changed battery and it was ok, i rather have a measurement as this than values that are realistic but still wrong

[@FKnoph]

#askgcntech Hi guys! Just curious... Is it possible to make the world's fastest skinsuit by dipping Olli in latex sealant? Future video?

[@gcntech]

😳

[@simonandrachelperchard5779]

How do drainage holes in rims work? Whar cavity is being drained? How did the water get in in the first place????

[@gerrymcbride6429]

@simonandrachelperchard5779 Its just the cavity in the aero fairing section of the rim. Water can get in through the drainage holes and get trapped when you rotate the wheel or it can get in through the spoke nipples as there is no requirement for these to be sealed.

[@JeffreyWilliams-dr7qe]

What is the latest fit and fashion of bib shorts and grippers. Some lack of continuity in this.

[@maikszczerbuk613]

#askgcntech I have an entry level gravel bike with a suspension fork without lockout. I want to upgrade it to make it faster, especially uphill, which option do you recommend: A decent/budget friendly rigid carbon fork Or, for the same price A new set of wheels (currently 1,15kg rear wheel) Thanks in advance, love the show

[@feedbackzaloop]

Great way to remove stickers is with injecting alcohol underneath them. It doesn't dissolve the glue but breaks its bond, so you need very little of alcohol, it works near instant and you can even re-apply the stickers again or put them undamaged on paper for scanning And of course there is no risk of damaging paint or epoxy like with gasoline or acetone.

[@gcntech]

Oh that's a great tip! 🙌Have you removed stickers in the past? Custom designing your bike is always super fun!

[@feedbackzaloop]

@@gcntech plenty! Even submitted couple to the bike vault, but apparently my designs were too radical

[@184cWayne]

#AskGCNTech I use a Neo Tacx2 Smart Trainer and came across a little snippet on the Garmin website that went something along the lines: Incline resistance is set at 65kg and the heavier the rider the less the assimilation of resistance will be. So as a 100kg cyclist does that imply I am flying up the hills quicker than I would in real life? Sure doesn't feel like it and I am getting pretty knackered anyhow. Just how much of a difference does this make?

[@PoulHansenDK]

Clearcoat on a matte frame will make it gloss/shiny!! If you get water in the rim, there must be somewhere it comes in!! So it can come out the same way it came in!!

[@gcntech]

Very true, you can often dry them out 🙌

[@MrAyley7]

#AskGcnTech Good day Ollie, I’m taking my girl to her first proper mountain climb ride and I’m planning to use cables to tow her up the steep parts of the mountain. Pusing her is out of the option since roads there a bit narrow. So towing her is the best choice and an additional weight training for me as well. Any recommendations on how to do this safely? (I’m using aluminium bike, no carbon parts and she’s on a steel roadbike no carbon parts as well) I’ve seen videos of some people doing this but they’ve never really replied on what cables/carabiners/latches to use. Hoping for a response. Thanks! 😊

[@janeblogs324]

Get her an ebike or she'll quit on day 1

[@RockyScorcese]

I have Zipp 303s and they do have drainage holes

[@arthas2605]

I've had water sloshing around in my Zipp 303 Firecrests as well after a realy long wet ride. But they do have drainage holes and over the next couple of days they dried out just fine, with strategic placemen to let the water run out and dry. No major issue, but very weird to notice the first ime ;)

[@gcntech]

It can be very weird when you spot it 👀 But nothing major to worry about, like you said - just let it drain and dry 🙌

[@gerrymcbride6429]

I got an FTP drop of 15% using Assioma Duo or Tacx Neo2 as compared to my original 4iiii LH crank power meter. My power balance is around 44%L/56%R 🙄

[@gcntech]

It's never fun to see a dip in your numbers 😢

[@christianwirth6965]

#askgcntech Hi guys, great show. My question is regarding chainring size. I have a Ultegra 12sp DI2 Groupset on my bike (R8170). I would like to go to a bigger chainset. I live in a predominantely flat area and I love the looks of a bigger chainring (also YOLO). Shimano only goes up to 52-36 on the ultegra and the bigger 53-39 and 54-40 are reserved to Dura Ace. Is it possible for me to install a bigger chainset on my groupset, or is that not possible? Any advice would be greatly appreciated. Thanks!

[@sbccbc7471]

If there's an aftermarket option for the Ultegra FC-R8100, yes.

[@jackgracie6228]

#askgcntech I seem to be getting corrosion on my spokes and the spoke nipples. I’ve already had one spoke break. Is there any way to rectify and prevent this?

[@sbccbc7471]

You likely have alloy nipples, which are more prone to suffer from corrosion. If a spoke broke not because something hit it, it's likely caused by uneven spoke tension. A wheel with even spoke tension won't break spokes on its own. One option you have now is to have the wheel rebuilt with brass nipples (heavier, but corrosion-resistant) at a reputable wheelbuilding studio.

[@TimR123]

#askgcntech, quite often when you're talking about 'marginal gains' you (Ollie, this means you) will run through some math on what x watts means over y time and z elevation. Is there a calculator out there that can let one play 'what if' games like this? Ideally one that can analyze your existing data to say on this ride, putting out 5W more (or saving 5W with the new tire) would result in this time?

[@lachlanbuchanan3541]

Pirelli P-Zero tubs have latex inners, not TPU. That would be why they’re going down

[@Deauville9189]

The newer Zipp 303s models do have a drainage hole, but the earlier models do not

[@davidchamplin8980]

I am looking to upgrade to di2 (preferably 12 speed) and I currently have mechanical 11 speed ultegra. Should I go with 105 or ultegra 12sp di2? Do you think it is worth the extra 1000 £€$. Or do you have any alternative suggestions. #askgcntech

[@JonCannings]

Ollie knows stickers, just look at his laptop! #StickerBoy

[@gcntech]

Does sticker bombing your bike make you more aero ... 🤔

[@feedbackzaloop]

He clearly is not the one to _remove_ 'em...

[@ime06]

#askgcntech Hi GCN team, I've recently got a new temporary job which means I'll be driving to work instead of cycling, so my commuter bike will go unused for 1-2 years. How is it best to prepare the bike for long term storage, and is it worth doing any maintenance while it's being unused to protect the components? I was thinking of doing a deep clean and lubing the chain, and then leaving it untouched until I need it again. It'll be stored in a dedicated bike shed in my garden, in the UK. I have Shimano 105 mechanical and the components currently have plenty of life in them. Many thanks

[@2.old4this]

#ASKGCNTECH - Tech Gurus I need your help. I bought a Wahoo Kickr V5 (11 speed, 11/28) and put my brand new Genesis Croix de Fer titanium bike on it (11 speed 11/34, with GRX Groupset and 48/31 chainrings). This is the first time I’ve used a smart trainer. When I peddle there is a gap of 3-5” of rotating the cranks before I feel engagement. Initially in lowest gears but whilst Conor smashed us last night in the GCN 30-in-30 (unless you’re with Dr Ollie who clearly thinks 30=60!!) this ‘slip’ or ‘gap’ in the crank is also happened in larger gears too, always in the 31 chainrings . Help! Please?

[@felipeaguila3039]

#askgcntech you have talked a lot about who dry lubes are sh*t and the advantages of wax. What do you think about wet lube? With proper care, it's a reliable alternative, even in dry conditions (road)?

[@___Bebo___]

Not using wet lube is a waste of time. I suggest Chain L, it lasts 1000-1500 miles per application and is smoother and quieter than any wax or PFTE dry lube.

[@JoggeTheDirector]

Hi Ollie and Grunt. This morning I was gonna ride my mountainbike with hydraulic disc brakes, but the brake fluid was frozen. So the bike was rendered useless. Is this a common winter problem when it’s close to -10 degrees celsius? Do I need winter specific brake fluid? Thx in advance! Cheerio

[@gerrymcbride6429]

@JoggeTheDirector If your brake fluid is frozen at -10C then it is probably water contaminated and needs changing. Both DOT and mineral fluids should continue to function well below -10C

[@TheMoodyedge]

#askgcntech I went for the first ride in months the other day and unfortunately went right over a huge pothole (4 inches deep) The hole was full of water and with water streaming down the wet road, it was invisible. It was a big impact which caused my shifters to be forced downward and inward and the plastic headset top cap was forced down and forward over the top of the headtube and has cracked/flaked the paint off in a few places along the top edge. Now I'm left feeling uncertain about the safety of the bike and a tatty paint job which is very annoying. Obviously having it repainted would void any warranty. I rang a local bike shop and they seem to think it should be fine and to remove the fork and give the steer tube a good check over. I imagine this is a very common occurance, especially here in the lake district. It's a Yoeleo R11 which I got last year. The front carbon wheel and tyre were fine which was surprising. I don't have the means to start having it shipped around and xrayed etc so that option is out. Any experience of such scenarios?

[@TerjeRiisnaes]

If you’re getting carbon rims for the first time, I suggest getting brake pads that are meant for carbon rims.

[@gcntech]

Great point! Carbon rim brakes can be interesting 👀 You can always make the jump over to disc brakes...

[@sbccbc7471]

New rim brake carbon wheelsets almost always come with a set of compatible pads.

[@aidansiemannmusic]

#askgcntech They've put salt on the streets to prevent ice forming where I live. Should I stop riding outdoors until the temperatures rise? How much of an issue is it going to be for my components and bike overall if I keep riding on salted streets? Will it be a problem even if I wash my bike afterwards?

[@eddiewards123]

Salt speeds up corrosion/oxidation/rusting. Rinse off salt and dry, don't leave it wet!

[@___Bebo___]

Your health is more important than some dumb bike, ride the bike when you want to. The pros toss these things in the gutter after 6 months.

[@mb10kx]

Still I never can get it to fit as well as you guys? 106 cm chest makes me a large but 84 cm waist is a medium, if I try medium it feels like I can't breath properly, extremely tight around the chest and neck, however I can still close the zipper (so it fits?). In a Large it's a bit loose around the belly and comfortable, so I end up wearing them large but it's not the most aero. Also medium barely covers my belly button. Cycling jerseys just don't fit me very well, they never really stay in place and the sleeves creep up. And sizing between brands is all over the place. I have an M in one brand that fits like an L but for another brand the XL feels like an M. Bibshorts straps are almost always too short because I need M for a close fit. Most Italian brands are the worst, the fit is just too short. Conclusion finding good fitting cycling clothing can be very hard, if you dont have the average cycling physique.

[@lastskywalker2481]

What about bibs without a padding or too tight stretch in the crotch/ balls area? I feel like my saddle is fine, but the pressure coming from the bib makes me numb down there. :/

[@Shadowboost]

Assos

[@lastskywalker2481]

@@Shadowboost really? do you have a specific bib name? thank you

[@Shadowboost]

@@lastskywalker2481 mille gts or gto

[@a1white]

Wow. Ollie’s exploding wheel in the kitchen story 😅

[@playandteach]

0:20 Auszeit...Alex doesn't know how to pronounce it, but then does a pun on the meaning?!

[@H457ur]

When it comes to clothing fit, my primary considerations are 1) nothing should flap - I hate it when clothing sounds like a flag in the wind, and 2) compression is king - I like my clothes to be very snug as I feel like the compression helps with fatigue. This is a *highly subjective* thing and, if you are not fit, wearing extremely tight clothing can be less than flattering. But I don’t care how I look since I can’t see myself 😂

[@gcntech]

As long as your feel and look comfortable that's all that matters 🙌 Great to hear you are embracing the lycra life style!

[@Wilko2728]

Olly!! Please tell me where I can get hold of the Alpe D'huez hoodie or, maybe you can donate your one to me 🙏😉

[@dannyjbr8870]

#askGCNtech Hi guys, I recently bought a bike that came with tubeless tyres. They are Pirelli Cinturato's, and seem perfect for winter. Any safety pitfalls if I use them with tubes? They didn't seem to pop on the rims when i inflated them, even though they are deemed compatible with my wheels? Wondering if it's due to lack of sealant? Any help would be appreciated. Cheers

[@___Bebo___]

I have gone through 2 sets of Cinturato Velos using tubeless rims tubeless tape and both butyl and TPU inner tubes. They are crocheted tubeless rims, but hookless should work fine as well as long as you are using the proper size tire and wheel. There should be no problems either way as long as the tire is decently hard to get on the rim and you aren't running super high pressures. If the fit is kinda baggy that might be cause for some concern but it's really rare for one of these tight tubeless tires to blow off the rim in any config.

[@dannyjbr8870]

@___Bebo___ thanks for your reply. I believe the wheel aren't hookless compatible. They are Prime alloy wheels if that helps? Cheers

[@___Bebo___]

@@dannyjbr8870 If they are crocheted the inner tube is gonna push the bead into the wheel and make it perfectly safe, much safer than tubeless enjoy.

[@jani724]

Anyone else say outloud " the alloted time" in unison?

[@crypcase150]

App works or not. What alloy wheels for 40mm tires,rim brakes.

[@chuckmccracken4136]

Guys, in your analysis of the differences between the power measurement via the turbo trainer at the rear wheel hub and the power at the pedals, aren't you neglecting several large factors? The power at the pedals is that input directly at the rider interface without drive train losses. The power measured at the turbo trainer is after all drive train losses. Now, I am not saying that this accounts for the entire 25% to 30% of difference hs is seeing, but could it perhaps be one of the answers. I saw one study that showed an 80.9%-98% efficiency factor though I was unable to determine the conditions. In addition, both seem to claim +/-!% accuracy though nothing is said about stability of the measurement over time nor or drift over temperature. These are both significant factors which must be compensated for, which I know from my prior career as an engineer utilizing similar sensors. I did find information that said that the 4iiii power meter did contain temperature compensation. However, effects of aging are notoriously difficult to compensate for, especially in low end sensors such as these here. Bottom line is, I would expect some disagreement between the two owing to the losses as well as potential inaccuracies of the two measurements. Be aware that the inaccuracies are potentially additive as they may each drift in opposite directions. However, I will say that your suggested test (i.e. another turbo trainer for comparison) is spot on to getting to the root cause of the discrepancy.

[@gc641]

I say comfort is more important, one size up for shirts and jacket

[@miyui9269]

for jerseys go 2-3 sizes bigger. you'll go slower, but you'll look cool like a mountain biker. also wear shorts over your bibs if that's your gig 😅

[@Shmack_]

Different companies have different bib sizes along with jerseys. I’ve had to return plenty of stuff that didn’t fit but I also got stuff and it had pubes and smelled like ass so I guess everyone tried them on but most people take a shower and try them on NOT do a ride and sweat all over it and then say it doesn’t fit and return it or try on after a full day of riding and sweating before a shower🤦‍♂️

[@markbradshaw4960]

Draining wheels. Zipp 303s have drainage holes.

[@GCNuser123]

older ones didnt

[@arundelnet]

crank length powermeter...... may be the issue

[@cruachan1191]

IME fit on cycling kit is only true to size if you are built like the traditional image of a cyclist. If you are broader in the shoulder or the gut or around the hips then go at least one size bigger. Sizing also seems to be based on long legs short torso, and I'm the opposite. Just bought a summer jacket (was reduced from £100 to £28 so daft not to!) and all the reviews said go one size bigger, I did and even at that it's a snug fit on length.

[@gcntech]

Bike clothing sizing can be really tricky 👀It always changes a little between brands too, we always recommend triple checking your sizing and measurements 🙌

[@markricketts6957]

Cycling shorts are normally true to size and easy to get a comfortable fit. The tops are a nightmare for me as the arms are always much too tight for my biceps. I tend to use a rowing shirt as the fit is more suitable for my body shape.

[@gcntech]

You must be a lot more buff than we are 💪 😢

[@markricketts6957]

@@gcntech Ha Ha, not buff, just a different body shape since rowing is my main sport.

[@timstendel4900]

Jerseys vary much by manufacturer and country of origin. I wear a larger jersey than my bibs, so some "sets" won't work for me.

[@jeff_aurand]

Regarding your idea to go to the local bike shop to try on kit… if you do that you need to buy it from the local bike shop. If you go there to test fit clothing or components or whatever you need to purchase from them. They aren’t your free fitting room so you can then go online and rob them of sales. If everyone does that LBS will no longer exist.

[@jeff_aurand]

To elaborate, yeah, it might cost more. Pay them for having stock in house. Maybe for extra kits you can buy them online.

[@maheshbabu-fj3tx]

I’m not a Mamil , but I Rapha 😅

[@veloello1]

#askgcntech Let's say santa brought me a nice new bike with all 105 R7000 parts, but thanks to a December bargain I have a little spare cash. Which 1 part of the drivetrain would be the biggest bang for my buck upgrade (cranks excluded) to higher tier/aftermarket? Front mech/rear mech/chain/cassette/chainring/pedals/BB/etc? Or none of its worth it and i should just save my money for coffee and cake? I've already got a nice saddle and tyres, and my preferred handlebars. Sub £€$100 budget for arguments sake. Asking for a friend, don't tell my wife...🤫

[@dfhgjhg]

good lube and spare chain. Or save to change cassette range if it feels like you want to change the steps

[@___Bebo___]

There aren't really any good upgrades to make there. I would pick pedals out of the list you gave, but that also is a waste of money. Get a nice set of Winspace carbon wheels maybe? I don't like carbon wheels because they are stiff but a light wheel set is probably going to be the only upgrade to that bike you will be able to "feel."

[@___Bebo___]

Tubeless tires going flat in 2 days is why most normal people don't use them, working as intended, I'd just increase your tire size or change your frame material to steel or titanium if you need more comfort.

[@veganpotterthevegan]

Or just check your pressure every ride, regardless of the frame material. That has little to nothing to do with why people don't go tubeless.

[@___Bebo___]

@@veganpotterthevegan Why would I check my tire pressure every ride I am not on a system designed to sell you a 20 dollar bottle of goo all the time.

[@veganpotterthevegan]

@___Bebo___ plenty of people do it. Plus you could have a slow leak you're unaware of(especially with tubes) and can randomly be 15psi down even though the tire looks inflated

[@___Bebo___]

@@veganpotterthevegan I'm going to know if the tube is bad because I run my tubes at the lowest pressure I can get before they feel squirmy. I don't need to check my tubes before I ride maybe you do.

[@veganpotterthevegan]

@@___Bebo___ ok, then you leave your driveway and just turn around when you could have just checked them?🤡 *Why do you run your pressure so low? Don't wanna feel the road? I thought you loved road feel😎