Tyre PSI for TT's.
ma123
Posts: 87
Hi proberly another silly question but a couple of days ago while having a good at a 7 mile hilly TT route I punctured which wasnt caused by a thorn or glass, but there was two pinch holes in the innertube, Now is this down to inaddequate air in the tyre while pushing myself on the bike.
my wheels are normal road size 700 by 23 and I ride on Continental gator skinz or Schwalbe stelvio depending on which bike and im 15st, 6ft 2.
my wheels are normal road size 700 by 23 and I ride on Continental gator skinz or Schwalbe stelvio depending on which bike and im 15st, 6ft 2.
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For your weight i would run the tires fairly close to the max rated pressure - 120ish psi.
If the pressure is right and your still getting snakebite punctures, its because your riding isnt smooth enough - a pothole isnt a target.
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Im just over 14st and I get away running 90psi no problem. My rims are rated at up to 120 and are still true (i do have to re-tension every few months though). The roads I ride are full of potholes and I miss most of them but not all, infact I've hit potholes at 40 in the past without any issues (except it wasnt the most pleasant experience).
I really don't see why it matters too much about a persons weight, sure I'll shy away from carbon as im too heavy for its rated weight but still, I enjoy cycling, and not going to stop because people think im too big/heavy.
I have mine at 170psi (tubs). If clinchers, then 120psi usual max
I agree - whatever you're weight is, for a TT you want your tyres to be pumped to the max - far faster and easier.
I would have finished 6th that day with this time.
Ive never done any TT's or any racing before and plan to start next season.
P.S I may be 15st but its funny how many smaller blokes I pass on the hills, Magnus Backsted is 94KG/14.8 stone and he won Paris - Roubaix not bad ay.
Yep.
Rock hard tyres just aren't faster over rough surfaces, plus uncomfortable bikes can fatigue you more, which can be a factor in longer TTs.
However, if you really want a hard tyre but are limited to clinchers, then Tufo do a tubular that hooks on to a clincher rim, which you can inflate to very high pressures with no trouble.
The liklihood of the the tyre deforming is determined by two things: the force on the tyre and the pressure in the tube.
The kind of forces needed to caused a snakebite generally only occur when you hit a pothole or encounter some other kind of impact (ride over a ledge, stone). But the heavier you are, the greater the force will be when this happens.
The greater the pressure in the tube, the more force needed to deform the tyre and therefore the lower risk of puncturing.
So in summary, heavier riders should run higher pressures, but I would be very surprised if the puncture wasn't preceded by some kind of noticeable impact (unlesss your tyres were really very soft indeed say <60psi).
As far as the harder=faster debate is concerned, I would say that it's more important to strike a balance based onthe road surface - you don't want a rock solid tyre on a poor surface or you'll keep losing contact with the ground and wasting energy.
Paris Roubaix aint hilly though
wrong
Please, keep doing this - im a climber, and suck at TTs, if all my competitors are doing something this stupid, it will give me a bit of an advantage.
If your on a perfectly smooth surface, solid tyres would be the way to go to minimise rolling resistance. Unfortunately, there is no such thing as a perfectly smooth surface on the road - that vibration your getting through your 170psi tubs is you going up and down over lots of tiny hills constantly - so not only will you be hugely less comfortable than me, you will have a higher rolling resistance.
Clinchers at the proper pressure have the best rolling resistance - proof of this from anywhere that has ever performed a test upon it - me being lazy wont be linking you - but westwoodvelo's forums have some of the best TT specific information around - go look.
I love Windshire (Wiltshire) but hate the poor quality of the roads.
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