03-31-2023, 03:06 AM
(05-06-2020, 10:18 AM)Criminal Wrote:(05-05-2020, 11:25 AM)Paul L. Wrote: 140-160 PSI? Good grief, why? What size tires are you using? A typical 700 X 25c tire/tube combo only needs 90-110 PSI. Tubeless runs even less. Think about it: at 160 PSI, your tire is like a rock. If you run over anything sharp on the road, the tire is not going to deform to ride over it. The object isn't going to push into the road surface, either. It's going straight through your tire.
Also, you'd better check your rim specs if you intend to run those extremely high pressures. Nothing like running 160 PSI, hitting a good sharp bump in the road, and watching your carbon fiber rim explode.
BTW, I'm using Continental GP 5000s with tubes on Boyd 28mm carbon wheels, inflated to 100 PSI. Zero punctures in 1500 miles.
Hi Paul,
Welcome aboard!
You are correct about some tires being as hard as a rock at their specified pressures, but these are racing tires that I run and are designed to be at that pressure, reducing the tire surface contact area and thus the rolling resistance. The part of the tire tread that is contacting the road at it's specified pressure is also the area that is most reinforced and/or has the greatest depth. Running most tires (at least road types) below their recommended minimum pressure now exposes the thinner and less reinforced, or unreinforced part of the tire to contact the road which makes it more prone to punctures and accelerated wear, never mind the degraded/dangerous handling it will have at lower than specified minimum pressures. I generally run 19mm-25 mm tires for racing, none have minimum pressures below 120 psi. Yes, I do run lower pressure tires for training and general cycling in the 80-110 psi range (23- 28mm), but again I am maintaining the recommended minimum pressures to avoid the aforementioned problems. There are plenty of narrow mid pressure tires out there, but they are designed to run at lower pressures, and will provide contact with the road where the manufacturer designed it to be due to tread design, wider area of reinforcement, etc. The "hard as a rock" effect is offset by a rider's choice of other equipment; frame, rims, saddle, etc. Everything is made of a purpose and each has it specific limitations dependent on use, terrain, riding style, and or personal preferences. I have no problem riding tires with pressures in excess of 120 psi for mileage of 50 miles or more. I can take the same frame and rims and easily gain or lose 10-20% of efficiency depending on which tire I use. If racing that's a lot of difference! As always, regardless of road tire and rim, it is incumbent upon the rider to pay due diligence to road surface and potential hazards. I would rather take the chance of getting a flat than having a bumper up my butt. I do speak with decades of experience regarding this. Overall, the flats that I have gotten (relatively few considering my miles biked) have had nothing to due with running high or mid pressure tires. I have no significant experience in cyclocross or mtb; it may very well be that the above considerations do not apply to these disciplines regarding tire pressure regarding the frequency of flats.
This sounds nuts! (Not having a go at you, just it sounds nuts, LOL)
I had no idea anyone was running such narrow tires or such high pressures.
What racing are you doing and on what bikes? What tires are you using?
Thanks.