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What is optimal tire pressure for GP5000 32 tires?

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What is optimal tire pressure for GP5000 32 tires?

Old 07-10-20, 12:12 PM
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kingston 
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I used to lower pressure for bad roads, then I got a few pinch flats so I don't do that anymore.
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Old 07-10-20, 12:56 PM
  #27  
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I weigh 140lb and started with 60/65 psi f/r in my 32mm GP5k TLs. During my first long ride with them on my new Al bike, I noticed the ride quality was a lot rougher than I've grown accustomed to (spoiled by my FutureShock equipped carbon Roubaix), so kept dropping the pressure until I settled on 50/55.

I went tubeless because my experience with any and all tires has been that there's a certain pressure threshold below which the ride feels way smoother, but I've always been at risk for pinch flats when I didn't pump up to 10+ psi more than what feels best for me.

I don't mind losing a few watts (if that's even happening) at the beginning of a long ride if I feel fresher at the end due to less fatigue from road vibration.
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Old 11-28-22, 02:14 PM
  #28  
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Originally Posted by kosmo886 View Post
Seems I may be running at too high of a pressure then. I don't mind the right at 75 or so PSI. I figured a firmer tire would be faster...is this not the case? Seems like with 32 tires on a wide rim..something like 21mm internal width I believe. I should go in the 60-65 range for more comfort. Would 80 PSI equate to more speed? curious the difference? I've seen some studies on rolling resistance on these tires specifically and does look like firmer is better for less rolling resistance and presumably more speed...
On smooth surfaces harder tires go faster as less rolling resistance due to smaller contact area. On rough surfaces, the rubber in softer tires goes around imperfections in the road, harder tires lose energy going over them making them slower.
On 28mm tires I use 60PSI on front, 65PSI on the rear mimicking a GCM presenter. Any harder and a bumpy ride. With 32mm I would go 5-10 PSI less.

Last edited by jrs665; 11-28-22 at 02:17 PM.
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Old 11-28-22, 02:22 PM
  #29  
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Originally Posted by kosmo886 View Post
Seems I may be running at too high of a pressure then. I don't mind the right at 75 or so PSI. I figured a firmer tire would be faster...is this not the case? Seems like with 32 tires on a wide rim..something like 21mm internal width I believe. I should go in the 60-65 range for more comfort. Would 80 PSI equate to more speed? curious the difference? I've seen some studies on rolling resistance on these tires specifically and does look like firmer is better for less rolling resistance and presumably more speed...
The rider and bike system is almost continually hitting thousands of tiny bumps on real roads. A lower pressure helps the tire absorb these deflections so they’re not passed on to the wheels, bike and ultimately the rider. In effect this reduces the unsprung mass that has to be moved out of the way on each surface impact and subsequently reduces kinetic energy loss
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Old 11-29-22, 06:13 PM
  #30  
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I use the pressure calculator at zipp.com. Tubeless tires on wider hookless rims is what I use. Internal rim width makes a big difference. My latest 25mm internal width hookless rims require 10 psi less pressure than my 19mm IW hooked rims, with the same tire.

Last edited by DaveSSS; 11-30-22 at 07:17 AM.
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