Do Pros Ever Use Neutral Service Bikes? | GCN Tech Clinic

Do Pros Ever Use Neutral Service Bikes? | GCN Tech Clinic


– Welcome to the GCN Tech Clinic, where you send in your questions and hopefully I can help answer them so you can get riding or fix that annoying little niggle of a problem. So let’s crack on then, shall we? With the first question this week that comes in from Samir Cassim who says, “Hi Jon, I need some help. I have a GT grade carbon
with some tubeless wheels and I want to go tubeless, is there any continental cyclocross or gravel tires that can
be converted to tubeless?” The tires they were thinking
about are some Cyclocross Speed or the Cyclocross King. “Great show, thanks for the help.” Right Samir, I like your
idea of thinking there because the tubeless set
ups are pretty good, indeed. Now, unfortunately for you, those tires are not tubeless compatible because the bead of the
actual tire isn’t designed to work with a tubeless set up. So it’s no can do, I’m afraid. Now before people at home
start commenting and writing, you can do a ghetto tubeless hack set up. You can but like I say,
it’s not designed for it and the consequences of a failing tire, could be quite frankly
disastrous, terrifying. Not to mention, extremely dangerous so simply Samir, don’t
do it, don’t try it. Next up we’ve got a question
from Jack Ford, who says, he’s just got himself some new wheels and when they get out of the saddle, it sounds like the wheels
are rubbing on the frame. They were wondering whether
there was a lack of grease on the quick releases
and the contact point between the dropouts and
the quick releases too. So that rubbing sound, I very much doubt it’s actually coming from the quick releases
because they tend to make a bit of a clicking sound rather than a rubbing. So couple of quick things to do, is make sure you’re not
using tires that are too wide for your frames or brake
caliper’s clearances. So have a look and make
sure that basically, the tire’s not touching either
the inside of the chainstays or also the underside of the
actual brake caliper too. Failing that, have a check as well, to make sure that your
pads, of your brakes, are not set too close to the rim because when you’re climbing or putting a lot of effort through, the wheel or the frame can
tend to flex a little bit and in turn, giving you
that annoying rubbing sound. So just have a look at those two but it never hurts indeed, like you say, to put a little bit of grease
on a quick release skewer, as well as on the inside of the dropouts where the wheel sits,
in case you get a click. But as for that rubbing sound, I’m pretty sure your tires
may be touching somewhere so just have a look,
particularly like I say, if you’re using a tire
which is possibly too wide than what the actual frame or
brake caliper is designed for. Now Bernardo Dime, he’s
got a tire question for me. So can they fit a 23 or 25 millimeter tire on a Cyclocross bike
that’s currently fitted with a 33 millimeter tires and what inner tubes can they use? Can they use the existing
one for a 33 millimeter tire? That’s a good question, this because in the past,
Cyclocross riders and bikes, they used 28 to 30 millimeter tires and they were fitted on
to standard road wheels. So providing that your wheels don’t have super wide
internal measurements, then yeah, it’s absolutely
fine so just bare that in mind as for the inner tube selection, yeah, you will be able to get that existing tube inside
of the tire and the rim but it could well be an
absolute struggle and pain and it’s not gonna be perfect,
if it’s anything wider than a 18 to 25 millimeter tube. If you do try it, use
lots of talcum powder ’cause that’s your friend,
it’s ever so slippery and it’s gonna help basically try and get it in there a little bit easier. But really you wanna use
proper inner tubes for the job. Now propo90, they’ve got
themselves a clickey problem which nobody likes, so
they’ve got an issue with what they think is their crank set. Every time they spin it around, it clicks. Sometimes it does, sometimes it doesn’t so it’s not every time, is it propo? Anyway, it comes and goes
but most of time it happens, they feel like they’ve tried everything. Right okay, propo, you need to make sure that everything is
clean so there’s no dirt or grime or grit in between
any of the interfaces on your chain set and bottom brackets. So take it all apart and
give it a good clean up and then reassemble using
either grease, anti-seize or thread lock where needed or necessary. And hopefully that’s gonna
eradicate the problem. Failing that, and this is
something which can happen and sometimes people don’t actually spot or know where it’s coming from, it can be your front
derailleur gear cable, has slightly come through
and basically it’s clicking on the crank each time you pedal around and, of course, depending on
where your front derailleur is in the movement, so if
you’re on a little ring, maybe it’s not gonna be clicking, on a big ring maybe it will. So have a good look at that. Failing that put the bike in a work stand or certainly get of the ground and slowly, very slowly pedal
it forwards or backwards and actually look to make sure that nothing is rubbing
or touching anywhere, ’cause that could be giving
you that annoying click. Next up is a question from
santibabo panmanee, who asks, “I plan to upgrade my
groupset to shimano 105 di2.” Firstly, santibabo, that doesn’t exist yet so I do know what you’re
getting at though, you wanna go Di2, so it’s fine. “I went to my local shop and asked them, they said I need a
specific frame for Di2.” Do I really need a specific frame for Di2? Right santibabo, going to Di2, great move. I’ve never ever looked back on it. And the good new is, you
don’t need a specific frame for the job because of
actually some rubber, plastic covers that you can attach over the electrical wires of the Di2 and then they simply
self-adhesively attach to the underside of the
frame, the chainstay and any of those different tubes where the cable’s gonna rub underneath. Now as for batteries,
yeah you could go internal but like you say, that would
then require a Di2 ready frame. So you can get a water
bottle cage mounted battery. So its simply quite a long piece of metal that goes underneath
one of your bottle cages and then the battery and
assembly just mounts onto there and you’re good to go. Good luck with that one santibabo. Next up is a question form Erc Vider that’s particularly relevant
for this time of year because we are in the middle
of the Tour de France. So they ask, “I’ve never seen a pro use a spare bike from Mavic or Shimano neutral service. Are they even necessary
or are they present on a race just for sponsorship reasons?” Right, so yes they do use them. And most famously was stage
12 of the 2016 Tour de France where Chris Froome actually took to one because he had a crash, don’t
know if you remember this, but his right hand seat
stay actually got cracked, I think it was is right hand seat stay. So he actually took to
one of those Mavic bikes and then carried on riding
before his own team car, got to him so he could
carry on his own bike. And then back in 2010, Jens Voigt, he actually took to, he actually finished the
stage on one of those bikes, only I remember him saying something like, it was like riding on a child’s bike because it was the wrong size for him. Anyway, they are used and the reason you
don’t commonly see it is because generally the riders on them, will be a rider who’s in isolation. So likely they don’t have a
team car anywhere around them so a camera crew, they’re
not normally around either but believe me a few times
in each Tour de France or any major race, there is a rider who will end up riding one of
those neutral service bikes. So if you go to a race,
keep a close eye out because you never know and they’re quite easy to spot as well. Next up, a question from
Simon Morrissey, who says, they tried to remove the cassette from their Fulcrum Racing Zeroes and the cassette is gouged
into the freehub body and now they can’t
remove all the sprockets as there are burrs where
the cassette has dug in. Any thoughts why this has happened? Right Simon, well those
freehub bodies generally, they’re made of a softer
material than your sprockets so to keep weight down really because a steel freehub
body is gonna weigh a lot. So those tougher material sprockets, normally made out of steel, they wear slightly into
those freehub bodies when you’re kicking out the
watts, which I’m sure you are. So as you’re turning the
cranks and the cassette, basically it is beginning
to slowly indent in there. But it’s never gonna
go all the way through or certainly I’ve never seen that. As for trying to remove them, well, what you could do is get
yourself a flathead screwdriver and insert it in between the sprockets. Make sure that the sprocket
you’re trying to remove, is not attached to another sprocket because some sprockets come on like three or two stuck together. So put it in there and
gently try and twist that screwdriver like you’re
trying to undo it or tighten it and you should be able
to slowly prize it away from the other sprockets. Failing that get yourself a blunt object, so not a screwdriver really because that could well
give a little bit of damage to the rear side of the sprocket but from the non-drive side,
put a blunt object through and then gently tap it with a hammer and hopefully that’ll actually force it off of the freehub body. Now to remove those
gouges or indentations, you can gently file them
away but don’t go overboard because otherwise you could
well damage the splines of the freehub body so just
be very gentle with that. Now Victor Choi, they’ve got
themselves a cassette problem, “I was wondering if you have
a fix for me”, Victor asks. When I’m in my easiest gear, a 28 tooth, and in the smallest chain
ring and when I backpedal, the chain drops down 5 gears. The groupset is brand new and
has been adjusted properly. I took it to a local
shop but they don’t know why it drops down a few gears. It only happens in the easiest gear. Right then Victor, it does in fact, sound like an issue with your chainline but without seeing the actual bike, it’s hard to certainly diagnose
what the problem could be. Also make sure that the chain’s okay, there’s no stiff links in it whatsoever because sometimes on
those extreme sprockets, that’s where something like
that really gets noticed. But ultimately, Victor,
and I don’t want to sound like I’m passing off the question, why do you want to backpedal? You only go forwards if you pedal forwards so there we are but I do
understand the frustration because you want the bike
to be working perfectly. You know, either way it’s going but it could well be that
chailine, like I said. Good luck, Victor. Okay final question this week is from Charles Fitzpatrick, who asks, “How do I know when rims
have gone past safe to use.” Good question on this one Charles. Right, grab yourself something flat so a really good ruler and
then get yourself a section of the braking surface and then from top to bottom of that section,
just hold the ruler against it and what you want to make sure is that that rim is as flat as
possible against the ruler. If it’s showing signs of wear so anything more than a
fraction of a millimeter or any concaving of the
rim then it’s likely that that rim is going to need replacing. Also have a really good look too because when rims do become very thin, they do start to crack. It’s happened to me in the past and it’s not something that’s ideal because after all those wheels
do a pretty important job for you on your bicycle rides. Now importantly as well to remember, is that some aluminum rims actually, have tiny little pinhead indentations in the braking surface
and they’re designed to essentially disappear or become one with the
rest of the braking surface when you finally worn
out that braking surface and it’s time for a new rim. But like I say, that’s only on
some aluminum rims out there so if you don’t see them,
don’t panic and think, oh no, I need to go out and
buy new wheels straight away. Pop along to your local
bike shop, if in doubt and get them to have a look. Right I do hope that
you’ve enjoyed this episode of the GCN Tech Clinic
where we do our very best to answer your technical problems. If you’ve got one for me, leave it in the comment
section down below, using the hashtag on screen right now. And hopefully I’ll be
able to answer it for you so you can go out on your bike and keep smashing out those watts. Now do remember to like and share this video
with your friends too. Give it a big thumbs up
and don’t forget too, to check out the GCN shop
where we’ve got a whole heap of goodies just for you. And now for two more great
videos click down here, down here for loads of cool
new tech from Eurobike.

About the Author: Michael Flood

79 Comments

  1. #askgcntech the cassette on my rear wheel is starting to have play in them. I can tell when I hold a cog and try to move it. It moves a little. Is it still safe to continue using the wheel? Or should I change the freewheel hub?

  2. #askgcntech for this cyclocross season I want to go tubeless but don’t know how low to go tyre pressure wise in different conditions like wet mud or sand. Also is there a good way to calculate what tyre pressure is best to ride in races?

  3. @askgcntech Hi Jon, long time asker, first time watcher.
    I often feel something rubbing on my rim, grating almost, but I can't see what it is whilst I'm riding.
    There seems to be some kind of stain around my rim and a strange smell when I get up to speed. Any ideas?
    Thanks

  4. For the guy at 3:45 it sounds like something I recently had that was a beast to track down. I got a new chain and some Powerlinks but the link they gave me was for the wrong speed chain so it was just slightly wider than the chain. More often than not it would snag when going through the jockey wheel just enough to make a click.

  5. #askgcanything #torqueback
    hi gnc, really like ur channel. Keep up the good work!
    In some of your videos you talked about how to stay with faster riders. And my question is: When you are the fastest, how do you behave when everybody is slower then you and kinda holding you back?

  6. As a 200 lb rider, most low spoke low weight tires offer way too much flex when powering up a hill. I consistently got brake rub until I went to a more Clydesdale friendly setup.

  7. #askgcntech Is it possible to use the quick release skewer that comes with a Tacx trainer on the road? I want to switch between trainer and road and don't want to be changing the skewer every time. Is there something that says that such skewer only works on the trainer? thanks!

  8. A trick I found to find out if the tires are rubbing. Use short pieces of white electrical tape on the frame / fork in the likely contact points and go for a ride. Any rubs will show up on the tape.

    To remove a cassette cog that has created a gouge in the freehub body (something that happens to me a lot), I use two chain whips and pull the offending cog in the direction away from the body gouge. Your method will cause the gouge to enlarge.

  9. I've never "worn out" a rim. I've got an aluminum Mavic Cosmic front wheel that I've used for 95% of my training since 2002. Rears aren't quite that old, but they have many 10's of thousands of miles on them…..(but I don't do much training in the rain)…..My brake pads also seem to last forever.

  10. New bike from online supplier. 11-32 cassette S8000 group-set. Clicking on wheel rotation and noise seems to be from chain or cassette. Only on one cog 7th down from left to right. ( my favored gear). Returned to manufacturer who said they replaced chain and cassette. They took a month to do this and it’s returned to me still clicking in the same gear. No noise from any of the other gear? Can’t bare to return it again due to repair lead time. Brand new with <200km will this ware out of it or is there anything I can do?

  11. #askgcntech Do you need a torque wrench to put a non quick release bike wheel back on or is it safe to just do it with a normal wrench?

  12. Yes, my frame was not designed for Di2 either, but it works great with the external battery and the stuff they sell to help you guide the wires. You can hardly tell it's there and I will never go back to mechanical shifting. My next frame will be Di2 compatible but only because I am compulsive.

  13. #askgcntech if I buy a brand new front wheel and replace the hub and spokes correctly will it be suitable to ride as a back wheel? Also I was just wondering in a sprint against my friends I feel I get more power on the hoods. Should I be on my drops?

  14. I feel like I am almost a graduate of the Jon Cannings School of Bicycle Repair. You rock. I can predict some of your answers since I have watched so many of your videos. Seriously, I have learned a lot from you and Si.

  15. On the clicking crankset (propo90), I had a similar problem. Turned out that the orange reflector on the pedal had worked its way out and was touching the crank as it passed. Made a loud noise. I was delighted to have found it, as it just needed pushing back in.

  16. #askgcntech Hi Jon, is there any way you can use the 'hidden buttons' on the Dura Ace 9100 shifters/hoods to start and stop recording on a GoPro Session camera.

  17. I am in the position to buy a new groupset for my 2016 Roubaix I was gonna buy the new 105 but have been offered the previous Ultegra model by my local bike shop. What should I get? #askgcntech

  18. #askgcntech Had a crash and need to upgrade my groupset. What would be better? New Ultegra R8000 Mechanical or outgoing Di2 6800 Ultegra?

  19. #askgcntech The medications that I need to take for a recently developed condition will keep me off my road bike for several months due the potential dire consequences of cashing. Should I keep my Di2 and power meters plugged in during this storage period or just top them off? Also, any other tips you can offer for the safe storage of my pride and joy will be appreciated.

  20. I just Finished setting up a Specialized Allez Sprint. When I am seated There is a creak in the seat post. I have used fiber grip and have it torqued to 5.9nM (just below the Specified 6.2nM). Any ideas of how to remedy this annoying creak. Afraid I'm Scaring off my riding mates. #askgcntech

  21. 4:00 prop90 question. I had that. It was the crank arm slightly touching the derailleur. the derailleur cage wasn't properly parallel.

  22. @Victor Choi – In addition to Jon's advice to check your chainline, another thing that can contribute to the back-pedaling problem is a misaligned rear derailleur hanger. Park Tool Dag-2.2 can be used to properly align most hangers. If you do it yourself, be sure to check both the top-bottom and front-rear alignments.

  23. #askgcntech Hello Jon,

    I was curious as to wether it was possible to run Sram Red Etap as a 1x system? ditching the front mech to loose a bit of weight etc… If so, what things would you need to be aware/warey of when running it? Cheers, keep up the great content!

  24. #askgcntech Thanks for an excellent show Jon. I appreciate your clear and concise diagnosis of the many issues people raise. I have 28mm skinwall/gumwall tyres on my Bianchi, in celeste of course. Are skinwall/gumwall tyres and more suspectible to puncture than tyres without skinwalls?

  25. Pertaining to the back peddling bike that drops five sprockets, make sure your wheel is square with the frame. Make sure the axle is sitting all the way in on your drop-outs. Make sure there is no dirt on the drop outs.

  26. Hi Jon, I'm a long time viewer and I love all the content you put out. I have what I think is a BB issue. Whenever I pedal the bike, you feel a click on the down stroke of the right pedal, but you feel it in both pedals regardless of the gear. When I put it on a work stand and pedal the bike you cannot feel the click, only when I ride it. Do the BB bearing need replacing or could it be something else? Thanks #askgcntech

  27. #ASKGCNTECH I am looking to upgrade my Wheelset to the Vision Team 30 Comp. My question is that will my Shimano RX100 7spd cassete fit on a modern wheel like this, or should I look for something of the time?

  28. For the hub sprocket question – the gouges are from the rotation of the sprockets digging into the hub. I suggest tapping the teeth in the opposite rotational direction to free it (not outward like in the video)

  29. #askgcntech How do you gauge when to replace tires? It’s my first road bike/tires and I usually use the tread as reference. Thanks! You guys are awesome

  30. Hi Jon, I just bought myself a new budget bike with a shimano acera/atlus drive train and I after indexing the front and rear derailleur I am still having issues with shifting from the big ring down to the smaller at the front, what would I do? #askgcntech

  31. For the question at 4:00 see if your FD cable end isn't touching the cranks when pedalling!

    Öhh sorry should have watched longer before commenting…

  32. Hi – on my commuter bike, I have an issue with the chain dropping from the big to inner chain ring. It only ever happens when I’m mid-block at the back and shift up a gear (ie down the block into a smaller sprocket). I keep the gears well indexed and the chain clean and regularly check it with a chain wear indicator – this is the only problem I’m experiencing. What could be causing this? It is SRAM Rival 22. Thanks! #askgcntech

  33. #askgcntech I recently installed a Power2Max NG Eco power meter, with a brand new Rotor 3D 24 crank on my bike. Since then, despite my numerous attempts, I cannot properly tune my frot mech, always some (very light) chain rubbing is there. Any tips for it? PS I mount a Shimano Ultegra 6800. Thank!!!

  34. Re clicking on the crankset. Some people forget to take the front derailleur alignment sticker off as well.

  35. #askgcntech
    Hi John I have a 2018 specialized tarmac sl4 and fitted 26mm s works turbo tyres on the supplied wheels, DT r460, the frame can take up to 28mm tyres, but after a couple of rides I noticed tyre rub on the chain stays both sides, the wheels seemed flex, so I purchased some fulcrum racing 5 LG wheels have done a couple of red on these and still have the same problem.. These wheels also can be flexed easily by hand… Any ideas please.

  36. #askgcntech
    I am starting to find my saddle a little uncomfortable. It’s only 2 year old (3000 Miles) and I use a good pair of bib shorts. I used to be comfortable up to 7 hours however 3 hour is about the limit. I Ali use chamois cream. should I change my saddle

  37. #askgcntech I'm planning to get myself a pair of Mavic Cosmic Elite UST Disc wheels. They are tubeless specific but I was wondering if I could run a normal road bike tire (like conti's GP 4000 II's) with inner tubes on them. I really like the looks of the wheelset and they match my budget of around 500€. If it isn't possible do you have any alternatives for disc brake clincher tires around 500€?
    Thanks in advance, Greetings from Switzerland.

  38. #askgcntech My question now is, where do l buy the Mavic service bike? As l always ride in isolation with no team car and no cameras around! Bahaha.

  39. #askgcntech

    In regards to how to remove a cassette on a gouged hub body. Another way to remove this is with two chain whips on the cassette cogs opposite of each other on two cogs next to each other squeezing the handles together like squeezing channel-lock or pliers. You can remove them one at a time or clusters.

    I found this to be the easiest and safest way to do it without damaging the cassette cogs or further damage the hub body.

  40. My bike used to make click noise once every crank rotation at high torque, I refitted both pedals with new grease and tightened bolts on the left crank now it's all quiet and smooth

  41. @1:30 Disk brake squeal is much more effective at warning people around you of your braking action, including people in front and the otherwise oblivious pedestrians…. and it's free!

  42. #askgcntech What up Jon! I have a couple of small paint chips on the bottom of my chainstays, what should I use if I want to touch up those spots.

  43. Thanks, Jon, you are always worthy of a big thumb-up! I'd happily give you two thumbs-up, if I could. But I can't. I'm only allowed one.

  44. #askgcntech hey Jon great show! I am looking to upgrade from ultegra 6800 to R8050 di2. I have a relatively new 6800 crankset that I would like to keep if possible. my question is, can I use a R8050 di2 front deurailler with the 6800 crankset? thanks!

  45. "When do you ever need to pedal backwards?"
    One crucial example would be returning your pedal to the correct position to take off at the traffic lights. In that very example having the chain skip down 5 gears can make you do the bike equivalent of stalling.

  46. Great one this week JonnyTech, I liked your little demo clips in the cassette/hub question too. Brilliant public service, thanks.

  47. Do different chains have different life expectancies? I typically get about 2500km to 3000km before the chain on SRAM Force1 group set is at the 50% wear mark. My drive train is treated like royalty, cleaned after every ride and lubed when needed. Are there higher quality chains that would have a longer life?

  48. I have a new SRAM RED eTAP setup that I love… but having problems with chain rub while in the big ring/biggest three cogs of the cassette. I know cross-chaining is not the best but it's louder than my old Shimano 105, which seems wrong. The front derailleur is properly aligned and, interestingly, the rub only happens when I push on the drive side pedal. Why?! #askgcntech

  49. Jack Ford, New Wheels,,,,,,check to be sure the wheel bearings are adjusted properly if they are adjustable type. Wiggle the tire sideways/back and forth too check for loose bearing adjustment. Loose bearing can let the wheel drift into the frame or brake pads under load.

  50. hey #askgcntech/John. I have a 11sp SRAM Rival gravel bike and I was looking at getting a set of 650b wheels (to have one set with 650b x 2.1 and one 700 x 28). My question is can I get a cheap 10sp Wheelset and then use a Shimano 11sp mountain bike cassette? As I hear theres no difference between mountain 10/11sp but road 11sp is slightly wider. Thanks man love the show!

  51. #askgcntech hi I’m having problems with my rear brake, campag. It doesn’t stay centred after using it and rubs slightly. As a nearly 60 year old fella living in a hilly/mountainous part of Spain it’s absolutely to blame for my poor performance against the younger spanish riders.

  52. #askgcntech hi jon, been having an issue with my gears, it stays in gear from 8 to 6 then it struggles to pick a gear from 5 to 3 and then its fine again from 2 to 1. and this has only developed in the past week. thanks jon in advance

  53. #askgcktech What would cause a bike to "ghost pedal"? When I put my bike in the workstand and pedal it, then let go of the pedals, the cranks continue to spin. This mainly happens in the big ring up front and the small in the rear.

  54. Well here some info that I’ve had experience 1st is the clicking sound that mention on the crankset in the early video. Mostly is from over tighten of the crank which place too much of pressure on the bearing caps or spacer and it click once u turn it. I’ve experience it before and my LBS straight away mention that’s the issue. On the issue of back paddling that the chain drop 5 spoket that’s is common on small frame size and on narrow design chain stay frame which is totally no issue.

  55. #askgcntech I have a bent tooth on my outer chainring, FSA SLK T52/36 with BB30. Do I need to remove the crank in order to change the changering? should I replace both chainrings? and what tools do I need? apart from a torx key.

  56. Hi Jon,
    Related to a viewers current question, I have found the new Vittoria Corsa G Plus clinchers make a noise similar to rubbing when putting a lot of power into the bike on a climb.
    Mine are not rubbing anywhere and I think the noise comes from the lateral tread pattern.
    It doesn’t slow them down and they are great tires in all conditions. I’ve been riding them for 2 seasons.

  57. Hello GCN, great show i find it very helpful 🙂 I`m planing to buy new pair of wheelset and i really like Vision Trimax 30 KB (rim brake version), I ride Shimano groupset. They have this nice braking surface PEO. I`m wondering do i need special PEO brake pads for this rim? I have a friend and he ride similar wheelset with PEO surface and he use Campagnolo special brake pads. Tnx in advance! #askgcntech

  58. #askgcntech Jon – was catching up on some of your videos and saw one where you showed how to install chain rings. Well, after watching it and looking at my bike I realized my small ring is on backwards. It's a SRAM 10sp chain ring on a Quarq crankset. It's been like this for about 2,000 miles of riding, with about 100 miles being in the small ring. Have I done any damage to the chain ring or chain? I haven't really noticed any issues other than when I'm in the small ring I get that cross chaining sound where the chain rubs the FD when I still have 3-4 sprockets to go down the cassette. By then I usually just shift up to the big ring. How critical is it that I fix it? #askgcntech

  59. Hi John, I'm currently working overseas and am only catching up with the tech clinic but I needed to get an answer to this as quick as possible. I am currently running a DuraAce 9000 mechanical groupset on my TT bike but have the opportunity of purchasing a SRAM red Etap TT upgrade pack. Is it possible to put the upgrade pack on and still run the bike with the DuraAce cassette, chain, chain rings and brakes. Hopefully you or one of the very knowledgable subscribers might be able to help me out with this question. Thanks. #askgcntech

  60. I want to ask some review from you. I've noticed a groupset named Sensha Empire which has a 11-speed groupset thats shifts like an ordinary Sram shifter. It costs right around $130.90 which is oddly cheap from where I'm located at. Any thoughts about this? #askgcntech

  61. #askgcntech could I convert my Pioneer dual sided power meter to 1x for flat races? I know I'd need a thicc-thin, but what about everything else? (6800 Shimano Ultegra cranks)

  62. Hi Jon, I’ve got a question on minimum tyre pressure: Following Si’s specific advice (bit.ly/2utM7QC), I have been riding my 28C tyres at 70psi / 4.8bar at the front and 75psi / 5.2bar at the rear, which works perfectly for me (I weigh 82kg). Now I have discovered that tyre manufacturers like Continental and Schwalbe specify a minimum pressure that is way higher, ie 87psi/6.0bar for the Schwalbe One and even 94psi/6.5bar for the Continental GP4000 SII. In my view that means giving away part of the benefit of wider tyres. Is it really unsafe to ride at lower pressures? Are there any recommendable 28C road tyres that may be ridden at or below 70psi?

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