I have a shorter left femur, about 4mm. I shimmed the left cleat with a 2mm shim, and moved the right cleated further rear ward by 3mm. I use Specialized shoes because they allow much more rear ward placement of the cleats. Depending on where the short limb is, femur/tibia/both, it's best to do as I describe so that when the pedal is at the 9 o'clock position, your leg length is adjusted for. Only using a shim is only effective at the top/bottom of the pedal stroke. Took me years to figure this out, but it's made a huge improvement in sitting squarely on the saddle.
High performance motorcycle tyres use a rubber which gets very sticky when it's up to temperature and run at a much lower pressure than bike tyres, maybe 20psi, as they don't have to worry about rolling resistance. This is why they can go round corners leaning not far off horizontally. I've noticed that Continental tyres tend to be a softer rubber than Vittoria, or at least they used to be back in the day, which might be because Germany has a cooler climate than Italy and the tyres are made to have a respectively lower operating temperature. There's a lot of talk about slowing down road racing to make it safer, which sounds like a good thing if the speed of the equipment has increased at the expense of safety. Tyre manufacturers are still generally prioritising speed and rolling resistance over grip, particularly in the racing scene. Now I'm not suggesting 20psi motorbike tyres, but if the UCI regulated tyres much like Formula 1 do, there is scope for more grip at the expense of rolling resistance. This would also appeal to many casual riders who would rather be safer than faster. It could be interesting to see how manufacturers would design a tyre to maximise grip on a bicycle tyre. On the subject of UCI regs (I'm getting into full dad-in-the-life mode now), I strongly feel that weight and dimensional limitations should be proportional to the size of the rider; smaller riders' size counts enough against them already without having proportionally heavier bikes, handlebars too wide etc.
For all my TPU tubes work a separate plastic valve stem, I've made it a habit to wind just a bit of Teflon tape (2 layers) around the thread to help it bite and act as a seal. Touch wood, I've had no valve leak issues.
5:59 guys it’s simple maths. If his leg is 10-20mm shorter a longer crank will help so long as the crank plus the cleats don’t go beyond his leg length. His leg is still 10-20mm shorter at the top of the stroke and will level out with the appropriate crank length.
Two comments. Assuming my Trek Domane has Bontrager sealant, it works well. I've found 3 spots that ooze a little sealant but I didn't lose tire pressure any faster than before the punctures. And it was 7 months old when they happened. I looked it up on their site and it has synthetic latex, though, but no ammonia. Don't know if that satisfies your allergy. For the TPU tube question, I CYCLAMI tubes from Amazon. The have metal stems that held up well.
Saw a video recently that showed how to make your own sealant by dissolving chunks of expanded polystyrene in acetone. Haven't tried it but it looked interesting.
I have a LLD of 20mm. Just had a bike fit and my cranks are 172.5 and my shoes were fitted with shims and g8 insoles along with spacers under my cleat Made a huge different to me
Regarding chains I've read on several platforms that sram chains can be quite aggressive on the cassette. Probably better to change the chain at the .5 rather than the .8
#askgcntech Hi guys, this is a follow up from ericharman4064's question. As Ollie mentioned, "best thing to do is experiment and play with it yourself". How can we actually test it out if the tyre pressure actually suits my cornering?
the reason for the rotational arrow is to insure that you do not reverse the direction of rotation after removing the tire. the *used tire* may be damaged by reversing the rotation, separation of the composite materials is likely if you reverse the rotation. this is key to those of us whom use seasonal or special purpose tires, such cyclocross, mnt biking, and the new fad - specially bike, "GRAVEL". reverse rotation at your own risk.
Regarding the leg length discrepancy: I have a leg 5mm shorter than the other. What I do is have a 5mm spacer between the cleat and the shoe. I had a good friend in college who had a massive leg length difference from a birth defect, and his spacer was about 30mm. We raced together, and the difference in his leg length didn't affect him from what I saw. My spacer is made from Vibram, which is pretty tough and used in the manufacturing of boots. I've had a local cobbler make a new spacer every five plus years or so.
5mm might not seem like much, but I'm tall (6'4") and have relatively narrow hips (30" waist) so the difference caused a tilt in my hips that was becoming increasingly painful, and was causing the disc in the vertebra in my lower back to compress. Since getting the spacer, I've had no problems riding the bike, or with back pain.
Vegelatex it's just Xanthan gum with olive pit grinds and cellulose fibres, washes off easily with water, but works better with larger tyres at lower pressure
I once had some Conti OEM tyres and, although I looked very hard, I couldn't find a direction arrow. Maybe the guys fitting them in the OEM factory don't need one. Fortunately, because they were Contis, it was obvious which way round they were supposed to be mounted.
TPU tube patches use a polymer cement. Similiar to super glue or JB weld but a different formula. Butyl tubes use a vulcanizing agent to bond the patch with the tube. I doubt a vulcanizing agent is going to do very well on something like TPU tubes which have no rubber to vulcanize.
#askgcntech: What about just replacing the solvent for the sealants after they have been in your tubeless tires for months? This would seem to be better than just adding more and more sealant. Can ammonia or glycol be used with a variety of sealants to replenish the solvent? Yes, yes, tires wear out and need to be replaced from time to time depending on the mileage ridden. If one doesn't ride a lot of miles a set of tires may last a couple of years. Simply adding sealant every few months would seem to accumulate a lot of sealant. Also, I have an extra set of wheels for my bike for spares in the event of a flat tire which might be difficult to repair/replace in a timely manner and am wondering about rotating them occasionally to redistribute the sealant and adding sealant or solvent to them every 3 - 6 months. Some expert advice re: all of this would be greatly appreciated.
Always now buy tpu tubes from china with metal valve stems a few grams heavier but you never strip the threads as plastic ones in the question and normally wrap ptfe tape round the core as well
If leg length discrepancy is predominantly due to femur then the crank should help, It won't do much otherwise. Then one should shim cleats or have a custom saddle. Either way a knowledgeable bikefitter with background in trauma and physio is much advised.
#askgcntech Hi, thanks for vids. Is there any benefit in non-integrated cabling for road stems, with hydraulic braking and electronic shifting? to me it seems there is no much to disassemble for maintainance, but some of my pals would pay extra for non-integrated. What are pros and cons?
A bike fitter will never recommend different crank lengths on each side - only to shim cleats. Not sure what flat pedal users do though, possibly insoles.
#askgcntech I have a triathlon bike with a SRAM 10-33 12 speed cassette on an 80mm deep wheel. I recently got a rear carbon disc wheel and would like to be able to swap rear wheels based on the course. Regular wheel for hillier courses, disc wheel for flatter courses. I am considering getting a SRAM 10-36 12s cassette, putting it on the regular deep dish wheel to improve my climbing ratio (I run 50t 1-by up front). Then I would put the 10-33 I already have (or possibly a 10-28) on the new disc wheel. My question is, will this be an issue for my derailleur/chain? It is setup from factory for the 50t 1by 10-33 combo and I want to seamlessly swap wheels when I choose. The Force 12s derailleur is rated for up to 36t cassettes but I wanted to be certain this change wouldn't cause chain length or indexing issues. Love the show, and thanks for all the great entertaining/helpful content!
On sealant without natural latex, i highly recommend Effetto Mariposa Caffelatex. I use it for more than five years on my gravel bikes. It have synthetic polymers instead of latex. By the way, ethylene glycol and propylene glycol are not substitute to latex, because those are solvents and antifreeze. So the reason you have glycols and don't have latex in some sealants is because these sealants are designed to withstand cold temperatures, and because latex has problems with the cold. But many manufacturers make latex-free sealants precisely because many people have allergies.
#askgcntech Hi guys recently my heart rate sensor has be giving phantom readings (as soon as I clip it on the strap even without wearing it, it shows heart rate at 80 and gradually increases) and was thinking maybe it was the strap. Is replacing the strap going to fix it or do I have to buy a new hrm? Tks
Over time, salts from sweat can accumulate in the strap, creating an electrical pathway for static electricity and giving false readings - especially at the start of a ride when the skin is dry. Pre-moistening the sensor pads can help create better electrical contact between the skin and sensor and allow the genuine HR signals to be read more clearly. Regular washing of the strap in fresh water can help slow the accumulation of salts, but ultimately the fabric strap should be regarded as a consumable. Replacing the fabric strap (keep the sensor unit) is definitely a good idea if you are getting false readings and washing or pre-moistening no longer helps. Replacement straps can usually be found cheaply online.
#askgcntech - Hi Olly, Alex (and anyone else!) I have a question about cadence. My normal cadence is around 65-70, and I really struggle holding the 80+ often mentioned as something to aim for. May be this is due to me coming from an MTB background, or possibly because I’m old and slow, but does cadence really matter?
I am almost 57, and usually hover around 65-70rpms, occasionally getting over 100rpms, but with 200-210 watts and my CdA at 0.200-0.210 I am getting 25mph (40.5kph) just fine. Dura Ace 54/40t and 11-30t cassette.
All of these Tyre inquiries are old hat for bicycles. Jan Heine addressed and revealed this now common practice over a decade ago! And... on the moto side...many many moons ago. 🙄😂 As usual, the road side of cycling is a day late and a dollar short...🤦♂️🤣
#askgcntech hi in your latest video showing bike cleaning this one( ua-cam.com/video/deCffAm8o0s/v-deo.html ), you have put the chain the wrong way on, and as this will increase wear you should fix it. also is it a good idea to use gravel tires for winter to avoid punctures?
I used to run my front 1.5" Continental Cross County MTB tyre reversed as it gave more grip especially when breaking. Mind you this was in the late '80s so things have moved on a bit now!
If your question was not answered, be persistent and use #askgcntech when asking away!💬
I have one leg that is 11mm shorter than the other and my bike fitter shimmed my cleats which made a huge amount of difference.
I have a shorter left femur, about 4mm. I shimmed the left cleat with a 2mm shim, and moved the right cleated further rear ward by 3mm. I use Specialized shoes because they allow much more rear ward placement of the cleats. Depending on where the short limb is, femur/tibia/both, it's best to do as I describe so that when the pedal is at the 9 o'clock position, your leg length is adjusted for. Only using a shim is only effective at the top/bottom of the pedal stroke.
Took me years to figure this out, but it's made a huge improvement in sitting squarely on the saddle.
High performance motorcycle tyres use a rubber which gets very sticky when it's up to temperature and run at a much lower pressure than bike tyres, maybe 20psi, as they don't have to worry about rolling resistance. This is why they can go round corners leaning not far off horizontally. I've noticed that Continental tyres tend to be a softer rubber than Vittoria, or at least they used to be back in the day, which might be because Germany has a cooler climate than Italy and the tyres are made to have a respectively lower operating temperature.
There's a lot of talk about slowing down road racing to make it safer, which sounds like a good thing if the speed of the equipment has increased at the expense of safety. Tyre manufacturers are still generally prioritising speed and rolling resistance over grip, particularly in the racing scene. Now I'm not suggesting 20psi motorbike tyres, but if the UCI regulated tyres much like Formula 1 do, there is scope for more grip at the expense of rolling resistance. This would also appeal to many casual riders who would rather be safer than faster. It could be interesting to see how manufacturers would design a tyre to maximise grip on a bicycle tyre.
On the subject of UCI regs (I'm getting into full dad-in-the-life mode now), I strongly feel that weight and dimensional limitations should be proportional to the size of the rider; smaller riders' size counts enough against them already without having proportionally heavier bikes, handlebars too wide etc.
For all my TPU tubes work a separate plastic valve stem, I've made it a habit to wind just a bit of Teflon tape (2 layers) around the thread to help it bite and act as a seal. Touch wood, I've had no valve leak issues.
Nice beaver
🎉 truly are a fountain of scientific knowledge. Alex, you and Ollie are fun presenters to watch. Well done, guys.
Nice one Alex' mum
Thanks so much!
On my MTB, I use the "Eco" version of Joe's No Flats sealant, it is just as effective as the standard version, but it's latex and ammonia free.
5:59 guys it’s simple maths. If his leg is 10-20mm shorter a longer crank will help so long as the crank plus the cleats don’t go beyond his leg length. His leg is still 10-20mm shorter at the top of the stroke and will level out with the appropriate crank length.
Never had luck with TPUs. Most I've purchased leak at the base of the valve stem after a couple of rides. Back on butyl because of this.
Two comments. Assuming my Trek Domane has Bontrager sealant, it works well. I've found 3 spots that ooze a little sealant but I didn't lose tire pressure any faster than before the punctures. And it was 7 months old when they happened. I looked it up on their site and it has synthetic latex, though, but no ammonia. Don't know if that satisfies your allergy.
For the TPU tube question, I CYCLAMI tubes from Amazon. The have metal stems that held up well.
Saw a video recently that showed how to make your own sealant by dissolving chunks of expanded polystyrene in acetone. Haven't tried it but it looked interesting.
🧐
I have a LLD of 20mm. Just had a bike fit and my cranks are 172.5 and my shoes were fitted with shims and g8 insoles along with spacers under my cleat Made a huge different to me
Regarding chains I've read on several platforms that sram chains can be quite aggressive on the cassette. Probably better to change the chain at the .5 rather than the .8
Was your microphone made by Campbell's Soup?
I think their microphone is in a bucket
#askgcntech Hi guys, this is a follow up from ericharman4064's question. As Ollie mentioned, "best thing to do is experiment and play with it yourself". How can we actually test it out if the tyre pressure actually suits my cornering?
Offbondage TPU tubes use a metal valve tube. Also cheap on aliexpress. I have been using them for ages.
the reason for the rotational arrow is to insure that you do not reverse the direction of rotation after removing the tire. the *used tire* may be damaged by reversing the rotation, separation of the composite materials is likely if you reverse the rotation. this is key to those of us whom use seasonal or special purpose tires, such cyclocross, mnt biking, and the new fad - specially bike, "GRAVEL". reverse rotation at your own risk.
Regarding the leg length discrepancy: I have a leg 5mm shorter than the other. What I do is have a 5mm spacer between the cleat and the shoe. I had a good friend in college who had a massive leg length difference from a birth defect, and his spacer was about 30mm. We raced together, and the difference in his leg length didn't affect him from what I saw.
My spacer is made from Vibram, which is pretty tough and used in the manufacturing of boots. I've had a local cobbler make a new spacer every five plus years or so.
5mm might not seem like much, but I'm tall (6'4") and have relatively narrow hips (30" waist) so the difference caused a tilt in my hips that was becoming increasingly painful, and was causing the disc in the vertebra in my lower back to compress. Since getting the spacer, I've had no problems riding the bike, or with back pain.
Vegelatex it's just Xanthan gum with olive pit grinds and cellulose fibres, washes off easily with water, but works better with larger tyres at lower pressure
8:46 water displacement actually
The shop I go to says change the chain after .5 but before the .75 marker on a chain checker
I once had some Conti OEM tyres and, although I looked very hard, I couldn't find a direction arrow. Maybe the guys fitting them in the OEM factory don't need one. Fortunately, because they were Contis, it was obvious which way round they were supposed to be mounted.
TPU tube patches use a polymer cement. Similiar to super glue or JB weld but a different formula.
Butyl tubes use a vulcanizing agent to bond the patch with the tube.
I doubt a vulcanizing agent is going to do very well on something like TPU tubes which have no rubber to vulcanize.
Is there a TPU patch kit??
#askgcntech: What about just replacing the solvent for the sealants after they have been in your tubeless tires for months? This would seem to be better than just adding more and more sealant. Can ammonia or glycol be used with a variety of sealants to replenish the solvent? Yes, yes, tires wear out and need to be replaced from time to time depending on the mileage ridden. If one doesn't ride a lot of miles a set of tires may last a couple of years. Simply adding sealant every few months would seem to accumulate a lot of sealant. Also, I have an extra set of wheels for my bike for spares in the event of a flat tire which might be difficult to repair/replace in a timely manner and am wondering about rotating them occasionally to redistribute the sealant and adding sealant or solvent to them every 3 - 6 months. Some expert advice re: all of this would be greatly appreciated.
Always now buy tpu tubes from china with metal valve stems a few grams heavier but you never strip the threads as plastic ones in the question and normally wrap ptfe tape round the core as well
Oko sealant is glycol based. On top of being arguably the best sealant ever.
If leg length discrepancy is predominantly due to femur then the crank should help, It won't do much otherwise. Then one should shim cleats or have a custom saddle. Either way a knowledgeable bikefitter with background in trauma and physio is much advised.
6:51 pedal height!!
#askgcntech Hi, thanks for vids. Is there any benefit in non-integrated cabling for road stems, with hydraulic braking and electronic shifting? to me it seems there is no much to disassemble for maintainance, but some of my pals would pay extra for non-integrated. What are pros and cons?
Sound deadening required in your studio pls - otherwise great 👍
A bike fitter will never recommend different crank lengths on each side - only to shim cleats. Not sure what flat pedal users do though, possibly insoles.
If I want to make gears easier should I get a smaller chainring or bigger cassette?
Cassette - cheaper & easier
ove the new studio but the audio isn't as good as before! too much space I think and thus reverb
hey, thanks for the feedback, we're working on it! cheers!
#askgcntech I have a triathlon bike with a SRAM 10-33 12 speed cassette on an 80mm deep wheel. I recently got a rear carbon disc wheel and would like to be able to swap rear wheels based on the course. Regular wheel for hillier courses, disc wheel for flatter courses. I am considering getting a SRAM 10-36 12s cassette, putting it on the regular deep dish wheel to improve my climbing ratio (I run 50t 1-by up front). Then I would put the 10-33 I already have (or possibly a 10-28) on the new disc wheel. My question is, will this be an issue for my derailleur/chain? It is setup from factory for the 50t 1by 10-33 combo and I want to seamlessly swap wheels when I choose. The Force 12s derailleur is rated for up to 36t cassettes but I wanted to be certain this change wouldn't cause chain length or indexing issues. Love the show, and thanks for all the great entertaining/helpful content!
#askgcntech Is it fine to leave bikes in the mechanic stand (clamped on the seatpost) for longer durations of time (e.g overnight)?
On sealant without natural latex, i highly recommend Effetto Mariposa Caffelatex. I use it for more than five years on my gravel bikes. It have synthetic polymers instead of latex.
By the way, ethylene glycol and propylene glycol are not substitute to latex, because those are solvents and antifreeze. So the reason you have glycols and don't have latex in some sealants is because these sealants are designed to withstand cold temperatures, and because latex has problems with the cold. But many manufacturers make latex-free sealants precisely because many people have allergies.
Oh, and they have one of, if not the best liquid chain wax according to zerofrictioncycling
I am applying to become your new sound recordist. I'm very good at checking devices are 'on' and the red button is set to 'record'.
#askgcntech
Hi guys recently my heart rate sensor has be giving phantom readings (as soon as I clip it on the strap even without wearing it, it shows heart rate at 80 and gradually increases) and was thinking maybe it was the strap. Is replacing the strap going to fix it or do I have to buy a new hrm? Tks
Over time, salts from sweat can accumulate in the strap, creating an electrical pathway for static electricity and giving false readings - especially at the start of a ride when the skin is dry.
Pre-moistening the sensor pads can help create better electrical contact between the skin and sensor and allow the genuine HR signals to be read more clearly.
Regular washing of the strap in fresh water can help slow the accumulation of salts, but ultimately the fabric strap should be regarded as a consumable. Replacing the fabric strap (keep the sensor unit) is definitely a good idea if you are getting false readings and washing or pre-moistening no longer helps. Replacement straps can usually be found cheaply online.
#askgcntech - Hi Olly, Alex (and anyone else!) I have a question about cadence. My normal cadence is around 65-70, and I really struggle holding the 80+ often mentioned as something to aim for. May be this is due to me coming from an MTB background, or possibly because I’m old and slow, but does cadence really matter?
Cadence does matter but it’s different for everyone.
I am almost 57, and usually hover around 65-70rpms, occasionally getting over 100rpms, but with 200-210 watts and my CdA at 0.200-0.210 I am getting 25mph (40.5kph) just fine. Dura Ace 54/40t and 11-30t cassette.
All of these Tyre inquiries are old hat for bicycles. Jan Heine addressed and revealed this now common practice over a decade ago!
And... on the moto side...many many moons ago. 🙄😂
As usual, the road side of cycling is a day late and a dollar short...🤦♂️🤣
Well, the road bike frame has hardly changed in the last... oh... 130 years. Maybe 1 day they will get around to riding something else ;)
Like the new set, but fire your sound recorder - sounds like they're in a box, with terrible echo.
we're fixing it, don't worry!
#askgcntech hi in your latest video showing bike cleaning this one( ua-cam.com/video/deCffAm8o0s/v-deo.html ), you have put the chain the wrong way on, and as this will increase wear you should fix it.
also is it a good idea to use gravel tires for winter to avoid punctures?
Shit hairdo mate
Fortunately this is a channel for cycling and not for hair dressing so who cares for the hairdo?
Your mum disagrees 😉
Thanks for letting us know who THAT guy is.
Audio is terrible in the new set. Not gonna watch till it’s fixed
Drop the marketing and faf! TPU or LATEX tubes
Sound still poor boys 👎
sound is bad
I used to run my front 1.5" Continental Cross County MTB tyre reversed as it gave more grip especially when breaking. Mind you this was in the late '80s so things have moved on a bit now!
You should probably be wearing gloves no matter what your sealant is. I wouldn’t trust any of that stuff to be non-toxic
The audio quality in your new digs still sucks. Hire an audio engineer.
Sound quality still poor
Take a day off
@ off what?
It's a talks show, not a classical music performance. I reckon the sound is as good as it needs to be.
And it's free.
@@marcushaysom4059 moaning
@@marcushaysom4059 moaning
I think Ollie should put on some weight. He used to be a bit more normal looking, and he was more humorous. Just saying.
I actually have about 2-3kgs more muscle now! but thanks! 😂
The shop I go to says change the chain after .5 but before the .75 marker on a chain checker