Chain Sizing, Oversized Jockey Wheels & Aero Valves | GCN Tech Clinic

Are carbon bikes safe to use on turbo trainers? Are shorter valves more aero? Why are my tyre patches so small? This and much addressed in this week's tech clinic. Put the kettle on, kick your feet up and take notes. As usual, get involved in the comments and share your tech questions.
00:00 Welcome to the GCN Tech Clinic
00:16 Is a steel bike better than carbon on a turbo trainer?
01:26 Are shorter valves more aero?
02:08 How do you size your chain correctly without the old chain?
03:11 Can you run the P Zero Race TLR Speedcore with a tube?
04:55 Are oversized jocky wheels easier to clean?
05:52 Why are puncture patches so small?
06:24 Do I need to worry about the air escaping after I pump up my tyres?
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[@gcntech]

Use the comments to share your tech questions! Use #askgcntech to be featured in future shows 🙌

[@richardhayward4537]

To answer the first question- my new BMC says not to use on turbo trainers, I bought BMC as they are solid bikes. I can’t post a photo of the instructions but they state ‘excessive loads on the dropouts may damage the frame’.

[@stevesneary2312]

As Alex points out most the air you hear when removing the pump hose is the air sound is coming from the hose itself. When reattaching the pump, the hose is stealing pressure from the tire. A shorter or firmer hose material will have less of this affect, but really isn't a problem.

[@nickkambitis5340]

The chap with the inflation question has misunderstood the situation. When he releases the valve the woosh of are is in the airline, not the valve. When he then puts his pressure gauge on to measure the pressure, a small amount of air is lost in the measurement process. I think he isn’t loosing anything!!

[@JanTrenson]

Exactly!

[@peteralexander6514]

Also a 5 psi difference is nothing since riding on a cold or hot day will change the tyre pressure more than that and noone seems to notice.

[@kokonanana1]

When replacing the pump hose, some of the air in the tire goes from the tire into the pump hose, thus making the gauge read lower.

[@nickkambitis5340]

@@kokonanana1 yes. Also I was trying to say when putting in the digital gauge to see what pressure you have, that would also take an amount of air from the wheel.

[@gcntech]

We mentioned this on in the video, it's an easy mistake to make but a great nerdy question!

[@sebastianreddan1647]

Hey GCN Tech, how about you get some hosts who understand tech and bike maintenance/repair in, maybe send these two back to the GCN I have a bike mechanic do all my work because I have no idea channel.

[@jack002tuber]

When you pump up your tires there is a VALVE in the wheel or tube, you force air against it, when you take off the pump no air escapes. None. The sound you hear is air compressed inside the pump

[@PoulHansenDK]

Bikes are NOT designed to move from side to side while the rear axle is fixed. Maybe he did a lot of powerful sprinting. Many people point out, "it's only been used inside", when selling their bike but to me this is not a good thing. I'd avoid a bike like that.

[@we1rd92]

Yeah idk how they didn't mention that. That's why on the turbo you sprint different to outside and shouln't sway your bike side to side.

[@lunam7249]

correct!! the torque on the bike frame skyrockects when fixed at rear by trainer

[@adamweb]

He could have tried to move his setup while the bike was attached. Manon actually mentioned making this exact mistake and cracking her frame in an older video.

[@kovie9162]

I just started using a direct drive indoor trainer three months ago, the Wahoo Core, and although my bike's frame is Ti and quite strong, very early I could see some potential issues if I wasn't careful. First is the side to side you mention during hard sprint, which doesn't allow the bike to sway right and left as you would outdoors with arear wheel. That's got to be hard on the dropouts and frame and trainers should be designed with some sort of give at the axle attach point to protect the bike. It also seems possible to do some damage if you're in a rush and don't fully drop both dropouts completely onto the axle so the bike ends up being cocked, which as you ride I imagine could do some damage. Also, as I think Manon pointed out in a previous video, if you try to move the trainer with the bike already attached by moving the bike, you could also do some damage at or near the attach points. Probably more so with carbon frames but bad practice in any case. The latter two issues can be avoided by being careful, but the first one is a bit of a dilemma. I wonder if you could insert a thin but hard polyurethane bushing on each side between the dropout and axle to give the bike some play when you get up and sprint, akin to car control arm bushings that prevent the arms and subframe from cracking?

[@rob-c.]

Manon: “Turbo trainers are designed to have a bike on them” Yeah I think the problem is that not all bikes are designed to go on turbo trainers 🤦‍♂️

[@daveroyle6310]

Tyre pressures with a track pump. Most of the escaping air you hear comes out of the hose so not the tyre. However, when you plug the hose back on, the tyre will empty into the hose to equalise the pressure. That's where the 5psi went. If you want to be more accurate, pump up to a higher pressure with a track pump and then use a digital gauge to slowly lower the pressure to whatever you want.

[@tomghc]

Some older frames were explicitly not supported for turbo trainer use (e.g. older Canyons, if I recall correctly). I've used such frames on turbo trainers for ages though. This person must be putting out some serious power / really swinging the bike

[@FML22]

True, but I think that person didn’t get one of the dropouts mated correctly to the trainer, and then clamped it down really tightly.

[@91dave]

Re the broken carbon frame on the Turbo trainer - it's quite possible that the same failure would have eventually happened when out on the road - so all in all it's a good thing it failed whilst on the turbo as otherwise it may have resulted in an injury! Better luck with the next bike, Dean!

[@rob-c.]

Possibly, but far more likely that having the bike clamped in a trainer by the rear axle, while the rest of the bike rocks from side to side has caused the failure.

[@grahamaustin9085]

Funnily enough, a friend has just had this happen - the non drive side seat stay has failed on a ride.

[@rob-c.]

@@grahamaustin9085 Have they had it on a trainer?

[@treyquattro]

I over-inflate my tires to compensate for the small amount of loss when disengaging the track pump. Works for me.

[@bikecommuter24]

same here I inflate a bit over, my pressure gauge has a release valve on it and I just adjust to the correct pressure.

[@ltrtg13]

I recently had to replace the chain on my road bike. I had to size the chain without using the old chain to help with the length. Actually, I couldn't use the old chain. As I have changed the cassette for one with a larger first gear and changed the cranks and smaller chainrings.

[@rotreklhypoteky]

Valve question is good question in my opinion. Look at for example on Aerocoach wheels. They went as far as hide valve in rim completely. There is of course gain there. If TT is your discipline, then sooner or later you will think about these details. Ollie would explain that :)

[@svenbe.4564]

Am I the only one having a laugh about the valve length question? 😂

[@bikecommuter24]

Adjusting Chain length, Calvin at Park tools has an excellent video on the process. If it is really complicated then there is no shame in going to a bike shop to have it done, something critical like proper chain length it is well worth the time and money spent to have it done correctly and have many enjoyable miles-kilometers of riding knowing it is done right.

[@yonglingng5640]

I've seen a handful of chains where they're just a little too long because most of them were installed with the chain routed over the smallest chainring & cassette cog and through the rear derailleur. They just assume as long as the slack is taken up, it's the right length, but some of these rear derailleurs have incorrectly adjusted B-tension gaps.

[@ThomasNing]

What a great set of questions this round 😂 That being said, I do pump ~2psi over for that reason...

[@johnstrac]

Re the valve question, shorter is lighter, it's win win !

[@donttouchthisatall]

I am sure 2g saved on the chain will get you up the stelvio pass much much much faster ;)

[@millermiller75]

Makes me feel better about my peepee.

[@FML22]

I’ve inadvertently ended up with valves slightly too short for my thumb-lock frame pump. I’d rather have a valve a few mm too long than too short.

[@gcntech]

Hill climbers dream!

[@whynotride327]

That was an unbelievably stupid question.

[@leissp1]

Typically the PSI has balanced between the tire and the hose....except with Lyzene screw on heads which have a pressure relief button which can on occasion unscrew the valve stem.

[@peterfranzjr.1190]

The air from the tire needs to equalize the air pressure within the hose from the pump when reconnecting. That's the biggest loss of pressure, especially on small volume road tires. Do the same test on 2.5" wide, 29" MTB tires and it's a lot smaller of an effect.

[@steven_willems]

Thx for answering my question

[@vo2maximus177]

Re: chain length, there's at least one excellent online resource where you feed in the relevant information: chain ring sizes, sprockets (biggest and smallest) and chainstay length (centre of BB to rear axle centre) and the calculation of how many links you need is done for you.

[@ricksmith2127]

What website is this?

[@gcntech]

That sounds great! We love a nerdy bike site 💡 Would you like a similar feature on the GCN site?

[@lbx5359]

Sram gives instructions in its derailleur installation manuals on how to size a chain. Wrap it around biggy-big while bypassing the deraileur, count the required extra number of links for your cage length, then break/install the chain

[@matthewho1053]

The rule of 105% stated that the rim must be at least 105% wider than the tyre to gain aerodynamic advantage. Some wheelsets like Roval Rapide CLX II and Reserve 40/44 has a wider external rim width at the front and narrower at the rear. Which tyre cobination is faster, using a wider tyre at the front and a narrower tyre at the back following the rule, or using equally wide tyres at both wheels which is too wide for the rear? #askgcntech

[@skipwalker1954]

Before I would buy a special bike for a Wahoo Kickr trainer, I'd suggest getting a Kickr Bike and selling the Kickr. Thats what I ended up doing. I waited for Wahoo to have a sale on factory refreshed Kickr Bikes and sold my Kickr to someone local. Both of us are happy!

[@johnandrews3568]

FWIW my dedicated trainer bike is a carbon Felt F2X - 'written off' after I was broadsided by a car. I've put 30,000km on the trainer bike on Zwift training rides and race and still solid as a rock.

[@cyclingcalifornia510]

#askgcntech has there ever been rolling Resistance test of used tires? I feel like some ties wear to faster state than others.

[@popeyebouldercreek]

Specialized recommended NOT mounting their carbon bikes on turbo trainers until around 2020. It is entirely possible that the broken 2017 frame came from Specialized not designing frames strong enough to deal with turbo trainer stresses, which are significantly different from wheel-on applications.

[@MandyH1972]

I don't have perfect pitch but I have very good relative pitch (probably from paying violin and cello) and if an instrument isn't well tuned or a player or singer's intonation is off I pretty much always notice right away.

[@markuss3718]

My electric pump says, not always but often, that unplug and replug makes me loose 0,1 bar which is 1,4 psi... The rest of the times it measures the same, so no loss.

[@Jari1973]

#askgcntech Has anyone researched how much balance affects a tubeless tire performance? The sealant always dries unevenly inside it.. I would think that there might be ten grams of this in some tires..

[@daveeaslick8686]

#askGCNtech A good chemistry question for Dr Ollie. It's understood that a tire filled by a CO2 cartridge bleeds the CO2 quickly after being filled over the next few days. Why aren't these cartridges filled with plain air? Plain air isn't flammable. And the air would stay in the tire longer.

[@Flojo-1]

#askgcntech Hi GCN TECH: My Ribble has 11-Speed 105 on it. Would a harder wearing chain like a Sram XX1 or Shimano Ultegra wear out the cassette and chainrings faster than using a cheaper, less hard wearing chain? Or is a hardwearing chain always the best route for longevity for all the drivetrain components?

[@DPS-Runner_Cyclist]

I have been wondering if the stress on the frame while it’s on a turbo trainer is the same as on a standard ride. Frame manufacturers surely optimize for standard riding, so how do we know the impact of the stress when riding on a trainer?

[@jonathankatz10]

#askgcntech Hi all, love your channel. I have used Speedplay pedals for years and love them. But I have been troubled for a while now that the recommended cleat lubricant contains PTFE (forever chemicals) which I would prefer not to use or be exposed to. Is there an alternative cleat lube that should work with Speedplay pedals? Thanks.

[@RoninCycling]

Hello Tech Gurus, I signed up for an ambitious summer; Triple Bypass (118 miles/10,800ft), Blue Sky (formerly Mt. Evans 27 miles/6,700 ft), and Cycle to the Summit (Pikes Peak 27 miles/4,800ft). I have an Alchemy Ronin Ti with 50/34 and 11-34 in the rear. I purchased a set of lighter weight carbon wheels. I currently have 28mm GP 5000. Would you recommend 32mm for some added cushion? Or do I attempt this on the 45mm Schwalbe G-One RS? I am also doing the GCN recommended workouts and what my p.t. bike fitter suggested. I am also doing climbs on Zwift. Would you recommend doing anything more so that I can actually finish. I thought about changing the weight on Zwift to 20 lbs more than I weigh. Would this be beneficial or is what I am doing sufficient to ensure I will finish. I do not mind suffering more now to suffer less later. Thank you for reading my novel.

[@overcookit1433]

I actually do care about the valve length - I got myself a thread cutter for presta valves to be able to make the valve of the inner tubes just a long as the rim is deep, and put in a special valve which is a mixture of a presta and a car valve. This is included in valve extenders for Campagnolo HPW Shamal/Bora rims from the late 90's (part code UT-HU100). For inflating, I use a brass valve extender which I can remove and close the valve hole with a piece of clear adhesive film (Tesafilm), so there is no valve in the wind at all - I am sure especially on fast descends with velocities of 50 mph+, it does matter.

[@gcntech]

please share that with us on the uploader! upload.globalcyclingnetwork.com the hacks/bodge section would be ideal!

[@overcookit1433]

@@gcntech I will do so; probably one picture which shows both the common presta valve and that special one, and one with the built-in valve in a DT Swiss ARC Dicut 80.

[@kevshields1604]

#Askgcntech Hi all can you please tell me if there is away of calculating watts , as back in the day ( 1970’s ) we didn’t have power meters . Say the ride is 70Kgs and ridding a 10 mile TT of a Time 22.00 minutes . It would be great to know what was the power we were putting out . Love show hope you can answer this question. Kev

[@markcobb2482]

Askgcntech. I bought a hand built bike in february and have not ridden it and wont be able to for another 6-9 months due to having leg surgery. Is there anything i should do to maintain the components so they are ready to go eventually. It is stored in a dry clean enviroment

[@TweexcoreUnderground]

#askgcntech I bought a new bike last year with an 11/34 cassette because I thought I would need the 34 for one specific event with a very hard climb. Last year I couldn't do the event because a friend had their wedding that weekend. This year the event is cancelled. The event is going ahead next year, but if I need to use the 34 up the climb, will I have any issues if I have never used that cog before? Should I use the 34 even if I don't need it just so it gets some use? Ps I will not be buying a different cassette and changing it for the event so please do not suggest that I am too lazy. There are no climbs that are on any of my local routes that require a 34

[@johnstrac]

#askgcntech I've tried this before but you advise us to measure actual tyre width when using tyre pressure calculators but not at what pressure to have when measuring. An over inflated tyre will have a larger width than it should have. Advice please.

[@daveeaslick8686]

#askGCNtech My bottle of chain drip wax froze for a few days while in my garage over the winter (I live in Canada). There is a warning on the bottle to not let it freeze. Is it still OK to use? And this got me to thinking, what about the wax on my chain when my bike is stored in my garage or shed over the winter? If the wax in the bottle shouldn't be frozen, what about the wax on our chains? Should we be dewaxing our chains when storing them for winter?

[@jbmo231]

#askgcntech; Hi Alex, Ollie and cheers to Manon from a Yank of Welsh descent. I'm a fairly active rider averaging 5000+ miles a year with no issues. This year, although nothing has changed on my bike, I started experiencing knee pain. I lowered my saddle ~0.5 cm and that solved the problem. I'm in my mid 70s, which makes me wonder - does one's bike fit change with age? Diolch - John

[@DailyRunRide]

Hi, GCN Morning

[@gcntech]

Morning 👋 Out on a ride today?

[@DailyRunRide]

@@gcntech yes, cycling at 4 am

[@gcntech]

@@DailyRunRide Wow that's great commitment! 💪

[@johnandrews3568]

Easy chain length hack is put it in the small chain ring, the smallest cog at the back and there should be about a half inch distance between the chain on the jockey and the smallest cog on the cassette.

[@johnbeckmeyer1696]

That sounds great for stopping the jockey cage and wheels from hitting in the case of small/small but it does nothing to ensure you can move to big/big!

[@johnandrews3568]

@@johnbeckmeyer1696 it works.

[@Gabizzle3]

#AskGCNTech Are heavier riders more susceptible to perineum numbness on the turbo trainer? I had a proper bike fit and out in the real world there are many bumps or changes in gradients where I force myself in different cycling positions. When I’m on the turbo in one position, I find myself feeling numbness after about 15 mins and have to switch positions. I am a heavier rider and would theoretically have more pressure regardless on my sit bones-should all turbo trainer users be changing positions up, anyway?

[@billcodey1430]

Old steel 10 speed on zwift hub works a treat.

[@gcntech]

Oooo what bike is it?

[@billcodey1430]

@@gcntech its a 1980 Columbia I picked up out of a recycle pile. Made it a single speed for a few years then stuck it on zwift hub trainer. Had to spread the rear triangle just a bit.

[@markbaker5345]

#askgcntech Hi Olly/Manon and Ian, 2 part question: With the trend towards larger volume tires what is the limitations of road bikes having a standard clearance of, say, 40c, would aerodynamics be adversely affected. Also why do alot of premium tyre models top out at 30c, which is the largest size I can find listed in retailers for the P-zero race tlr. Love the show.

[@gerrymcbride6429]

Conti GP5000s TR top out at 32c

[@robgruppetta]

#askgcntech Hi Ollie and Alex or whatever your names are. I'm off to the Pyrenees this summer with my mates and we've rented bikes with "French brakes" (ie, the levers are reversed). I've never ridden a bike with this brake setup. How much of an issue is it? Does it take long to adjust? Is there anything I can do to prepare short of changing my UK brake setup to French brakes? Thanks for your help!

[@91dave]

I suspect it depends how advanced your breaking technique is. As a relatively new rider (2 years), my braking technique (particularly on longer descents) is pretty much to apply equal pressure to both brakes, and I rarely think about using front over back or visa-versa. If your skills are more advanced, and you're specifically applying vastly different amounts of pressure to front vs rear brakes, you're more likely to notice initially. For what it's worth, when I hired bikes in Lanzarote with "euro" brake setup, I didn't find it a problem to adjust.

[@robgruppetta]

Thanks Dave. I use my front brake quite a bit but will try and modify my style.

[@terry_hutt]

#askgcntech I recently destroyed both my tires on a gravel ride. I only had enough boots and patches to get one of them to hold air again. I put the good tire on the back wheel because - traction. I had to ride 15 miles back to civilization. Steering was awful. Should I have put the good tire on the front or the back?

[@PaulTheCyclist.]

I am sure I have seen some aero valve caps recently.

[@gcntech]

Interesting! Would you run them?

[@cruachan1191]

You can cut patches to size as required. Personally, I'd hate to try and patch a tube at the roadside with anything smaller than I have though, it's fiddly enough as it is.

[@gcntech]

That's true! It can be very fiddly. Do use a spare tube and take the broken tube home to fix in comfort? 🏡

[@cruachan1191]

@@gcntech Usually, yes. Sadly last time I had a puncture on gravel ride round a wind farm my spare tube had a faulty valve. Hence the first hand knowledge of "fiddly", using a dirty pothole to find a puncture is not fun!

[@humpy125]

Park Tool have a video on how to size your chain

[@J_CART3R]

Turbo trainers designed to have bike on it. But, Bikes are not designed to put on Turbo trainers. He snapped it because the rear axle is fixed on the Turbo Trainers.

[@dbrooker8918]

Yes to that. I've noticed that any bike I put on a Turbo Trainer moves significantly in the Stays and Bottom Bracket area. So much so that I thought my chainset on one bike was not True but it was just the bottom bracket area going from side to side about 8mm..

[@bk34563]

newmen has wheels that hide the valve now. used by ICW on the WorldTour

[@mllobetc]

#askgcntech Hi guys, I was browsing for some reasonably priced knobbly 700x42c gravel tires and came across the "CST Pika tubeless ready". After looking them up I found out CST and Maxxis belong to the same parent company. Cheng Shin Rubber Inc. What's your opinion on this brand and their tire quality? What would these tires be best suited for? Should I stay away or...? (disclaimer: they are HALF the price of similar well-known branded ones like Pirelli, Teravail, Schwalbe, Panaracer or Continental... which makes all of my alarams go off with equal fear and excitement). Love the show!

[@vo2maximus177]

Carbon fibre bike on a turbo trainer....hmmm, perhaps not quite as simple and safe as made out here. Depending on the type you have, if both the front and rear dropouts are clamped into a trainer such that they're essentially fixed relative to each other, that can produce adverse forces in strange directions which the frame wasn't designed for, especially with out of the saddle efforts. If you have your front wheel fitted though and it's simply sitting on one of those plastic guides designed to go with that trainer and holds the front end at the right height while allowing movement, that's fine.

[@johnandrews3568]

Agree... i tried a fixed front wheel holder and I abandoned it after my bike started making creaking sounds that were not normal. Front wheel back on, back to normal.

[@jameslee-pevenhull5087]

Puncture patches. Buy a sheet of WeldTite patch. Cut it to your desired size.

[@chiliishot]

If someone is that worried about cleaning jockey wheels to spend hundreds on an OSPW, they should probably just switch to wax lube.

[@bama95]

#askgcntech Hi friends, I recently converted my weird looking 90s-mtb-converted-to-gravel bike from 26inch wheels to 700c. I previously had inner tubes with Italian valves (the ones with the little separate cap you screw in to close them down) and I loved them, but the cheapest option for 700c was presta. It seems like presta valves lose quite a bit of pressure after every ride or even during the ride, so much so that I have found myself having to stop to fill up some more. I checked many times for punctures and I am positive there are none. I can't imagine this is normal, so what could it be? Hope it makes it into the show next week🤞

[@johnbeckmeyer1696]

Having to top up your tire pressure in the middle of a ride is not something most of us would expect to have to do. If I had to guess, I'd guess that the tube(s) are of poor quality and are permeable or you have a slow leak from somewhere. Try putting your freshly inflated tire/wheel in some water and see if you can spot bubbles of air escaping. I've had slow leaks resulting in tires going soft in the middle of the ride, but it's not been because of the valve type - it's always been some kind of small puncture or cut when it comes to clincher tires with tubes. In the tubeless realm, I've suffered air escaping through the sidewalls (Rene Hearse Barrow Pass tires), gummed sealant creating gaps between the tire bead and the wheel (Bontrager GR1 Team Issue (fixed by thorough cleaning of the tire bead and wheel rim)), or sealant just not able to keep the puncture sealed (Stans sealant and 700x28 Continental GP 5000 (fixed by thoroughly cleaning and drying the inside of the tire and then patching the inside of the tire with a Park Tool GP-2 patch).

[@bama95]

@@johnbeckmeyer1696 thank you for the well articulated reply ✌️

[@larrylem3582]

If Rema could save money by making patches smaller, they would. But then they'd get a bad reputation for patches not adhering as well. They've likely figured out the optimum size.

[@a1white]

Take it to the local bike shop is the solution to 90% of bike related problems 😀

[@jakethesnake1976]

What useless advice re the chain length 🙄 put the chain over big-big and add on 2 links, done.

[@ShtopoRrr]

#askgcntech All your bike cleaning videos contain usage of water hose outside the house. Not everybody has access to a water hose and a place outside to wash a bike or car stations willing to let to wash bikes. So the question is, how to wash a bike in urban environment where all you have is a rented apartment in a block?

[@johnbeckmeyer1696]

A) A 3 gallon pump sprayer [a Google search link below] B) A friend's house or apartment, C) A car wash (not a drive-through, but one with a sprayer). www.google.com/search?q=3+gallon+pump+sprayer&rlz=1C5CHFA_enUS1009US1009&oq=three+gallon+pump+&gs_lcrp=EgZjaHJvbWUqCAgBEAAYFhgeMgYIABBFGDkyCAgBEAAYFhgeMggIAhAAGBYYHjIICAMQABgWGB4yCggEEAAYDxgWGB4yDQgFEAAYhgMYgAQYigUyDQgGEAAYhgMYgAQYigUyDQgHEAAYhgMYgAQYigXSAQg4MDExajBqN6gCALACAA&sourceid=chrome&ie=UTF-8

[@johnbeckmeyer1696]

Strange, my reply just disappears when I click on it. So, try getting a hand pumped spray washer - search google for "3 gallon pump sprayer" --OR-- go to a car wash with sprayers --OR-- do this at a friend's house/appt.

[@gerrymcbride6429]

I wash mine in the shower

[@ShtopoRrr]

@@gerrymcbride6429 yup, but it's rather ugly option

[@gerrymcbride6429]

@@ShtopoRrr No issues, I have a big shower. Waxed chain so no oil to deal with.

[@jonpoon3896]

That was definitely a non answer to the chain question

[@jalakere]

You talk a lot about what you carry with you on a ride and where to store it but something I'm finding very little information about is what kind of lock would make sense to have with you on a cafe ride to prevent some fucker from swiping your bike while you're paying for your coffee but that wouldn't impact weight or areo too significantly. #askgcntech

[@AndrewShakespeare]

You're kidding, surely? The answer to sizing a chain is to take it to the bike shop and have a coffee? Why isn't that the answer to every question? There are chain length calculators online, I'm sure I've seen Ollie using the Sheldon Brown method, and Calvin must have done some videos on it.

[@JeffreyWilliams-dr7qe]

You guys are sitting opposite from where you were sitting before. Please explain this development.

[@telekylester]

I would even think steel is worse for indoor training due to the sweat and potential corrosion issues

[@peteralexander6514]

lol - not many raw steel frames out there

[@johnbeckmeyer1696]

When it comes to galvanic corrosion - the kind of "rust" that comes from two dissimilar metals coming into contact in the presence of an electrolyte (sweat) - carbon and steel have less potential than carbon and aluminum to corrode. Carbon and steel are closer together on the galvanic series so they have less potential to react with each other. So all things being equal, a steel bike might be a better choice! Carbon and aluminum are further apart so they have a greater potential to corrode. Carbon and titanium are really close to each other and might pose less of a problem. Regardless, covering your bike with a towel to catch sweat and keeping it clean (free of salts) and dry will go a long way to help preserve it - especially where two different materials come into contact (headset, brakes, thru axel, bottom bracket, pedals, crank arms, chain ring bolts, spokes/nipples/rims, seat post, water bottle cages...). Here's a galvanic series chart for easy reference: www.corrosionpedia.com/an-introduction-to-the-galvanic-series-galvanic-compatibility-and-corrosion/2/1403

[@andrewc662]

If you wax your chain, the pulley wheel will always be clean.

[@kristiemclennan]

Or just watch park tools vid on how to size a chain

[@alistairmacfadyen9365]

Repair your carbon stay, its very easy to do... i just done it

[@gcntech]

Do you trust that it's as good as new?

[@alistairmacfadyen9365]

@@gcntech it is stronger than new, it was the top tube in my case, but if i was this chap i would source the kit, undertake a repair and use it as a turbo bike...

[@kyle3570]

first

[@gcntech]

You beat the bots! 🥇

[@billcodey1430]

in the alotted time???

[@gcntech]

⏱️

[@johnbeckmeyer1696]

@@gcntech Did Manon say, "We have 30 questions to get through today"? Had my hopes up!

[@Cycle.every.day.]

Why does Manon have clown make-up on in thumbnail, that's cruel.

[@PoulHansenDK]

Hmm, still bad sound, like sitting in a toilet 😁

[@christianholmstedt8770]

So you can't even answer how to size a chain.... @GCN sucks.

[@Quizmate1]

Indeed. I'm pretty sure there's a standard method, say on Park Tool's Web page or similar. I'd like to know the correct way if using a master link. Also not all bikes are set up properly in the first place, as I often find out on delivery 😒

[@gcntech]

If you need a deeper dive in the subject we have some great videos on it, just like this one 👉kzbin.info/www/bejne/sJLYeaSEfrdkfJI

[@charlesmansplaining]

@@gcntech The correct answer to sizing your chain correctly is to go to the manufacturers website and look up the tech documentation. They all have that information.

[@christianholmstedt8770]

@@gcntech Why did you bother to put 'chain sizing' in the video title if you never intended to answer it? The linked video is good but stop the click baiting.