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-   -   A Tire Pressure Thread (http://www.bikeforums.net/fifty-plus-50/947830-tire-pressure-thread.html)

HawkOwl 05-12-14 11:08 PM

A Tire Pressure Thread
 
I just put Continental Gatorskin 700x28 tires on. Their web site says the tire pressure range is 95-116psi.

What relationship is there between tire pressure, weight carrying and comfort?

Note: Some folks run some really low pressures. But, finally pinned down they confess to weighing very little.

zonatandem 05-12-14 11:11 PM

Comparatively, I weigh very little (135 lbs) and run 120 PSI.

daihard 05-12-14 11:28 PM

Quote:

Originally Posted by zonatandem (Post 16753586)
Comparatively, I weigh very little (135 lbs) and run 120 PSI.

How is the ride? I weigh about 140 lbs and run about 100 psi on 700x25s. The ride is fairly comfortable.

Barrettscv 05-13-14 12:11 AM

I weight 220 lbs and use 90 psi in the front and 105 psi inflation at the rear with a tire that size. A tire should deflect 10 to 15%. Less than this reduces traction and more than this increases rolling resistance.

FlatSix911 05-13-14 12:22 AM

1 Attachment(s)
Remember to split the Front/Rear wheel load 45%/55% for Road Bikes

http://bikeforums.net/attachment.php...hmentid=380056

akohekohe 05-13-14 01:08 AM

I was going to post a similar chart to FlatSix911. I might add that it is my experience that inflating a tire close to the maximum rated pressure will lead to significantly more flat tires. Of course under-inflating will lead to pinch flats and you risk damaging the rim.

OldTryGuy 05-13-14 03:20 AM

Quote:

Originally Posted by zonatandem (Post 16753586)
Comparatively, I weigh very little (135 lbs) and run 120 PSI.

135lb/140lb, 23mm tire at 120psi

A very hard, responsive ride.

Weatherby 05-13-14 04:21 AM

205lb rider plus 17lb bike puts me at around 100 kilos all in. 85 psi rear 75 psi front when riding Challenge Parigi-Roubaix. 100/85 when riding Schwab One 700x25 and 95/80 when running Vittoria CX EVO iii 700x25. Latex tubes.

Life is too short to run cheap rubber. Never had a pinch flat.

rdtompki 05-13-14 06:40 AM

190 lbs, 85/90 front/rear when running my Hutchinson Sector 28mm tubeless. Not pinch flats of course:)

jon c. 05-13-14 06:48 AM

At 143 pounds, I ride 25s at 115. Max pressure rating. I prefer a firm ride.

Dudelsack 05-13-14 06:59 AM

I weight 385 pounds and inflate the tires to 250 psi.

rumrunn6 05-13-14 08:08 AM

I'm 224lbs and I pump my tires to 115psi front & rear but some escapes when I take the chuck off, so maybe 110 or 105psi is left in the tires?

crazyb 05-13-14 08:08 AM

Quote:

Originally Posted by Dudelsack (Post 16754109)
I weight 385 pounds and inflate the tires to 250 psi.

Hand pump or co2?

donheff 05-13-14 08:36 AM

I too read the article that produced FlatSix's chart several years ago and reduced my pressure. My wife and I both ride at about 60 PSI on 28mm tires and haven't had flats in more than a year. The ride is also a bit more comfortable than would occur at higher pressure.

wphamilton 05-13-14 08:38 AM

I pump mine up to the max, which is only 100 psi on the 25mm I have now, so that I have longer before having to pump them up again.

If I had to choose a set pressure it would be 80/90 front/back. Total weight is about 175.

The chart says 70/85 psi but that just seems weird. It might be right though for all I know.

spdracr39 05-13-14 10:02 AM

I am 215lbs and ride on 100lbs 700x23. No problems and comfy ride.

VegasTriker 05-13-14 10:03 AM

High pressure more speed - Lower pressure more comfort
 
There certainly is a relationship between tire pressure, speed, and comfort. The relationship between pressure and speed is direct and between pressure and comfort is indirect. I bought a recumbent racing trike that came with Schwalbe Ultremo ZX 406 tires. The rated pressure is 85 to 160 PSI. If you run them at the highest pressure, you might as well be running solid rubber tires. The ride is incredibly harsh. The ride is faster though. I dumped them almost immediately for a set of Tioga PowerBlock tires rated at 35 to 80 psi. Much more comfortable at the rated pressure but slower. I don't like running Schwalbe tires much below the maximum pressure because of bad experience with premature sidewall failure. The sidewalls flex more at the lower end of the rated pressure range. It may mean a shorter life for the tire.

wphamilton 05-13-14 10:14 AM

Quote:

Originally Posted by VegasTriker (Post 16754745)
There certainly is a relationship between tire pressure, speed, and comfort. The relationship between pressure and speed is direct and between pressure and comfort is indirect. I bought a recumbent racing trike that came with Schwalbe Ultremo ZX 406 tires. The rated pressure is 85 to 160 PSI. If you run them at the highest pressure, you might as well be running solid rubber tires. The ride is incredibly harsh. The ride is faster though. I dumped them almost immediately for a set of Tioga PowerBlock tires rated at 35 to 80 psi. Much more comfortable at the rated pressure but slower. I don't like running Schwalbe tires much below the maximum pressure because of bad experience with premature sidewall failure. The sidewalls flex more at the lower end of the rated pressure range. It may mean a shorter life for the tire.

I don't think so. I think a speed/pressure curve has a maximum well before the highest pressure, other things held equal, and that the other variables complicate that even further.

Northwestrider 05-13-14 10:20 AM

It makes a difference, try it and decide for you.

BluesDawg 05-13-14 10:42 AM

I like to go as low as I can without risking pinch flats. I run about 70f and 80r in the Pasela TG 28s on my Casseroll and about 85f and 95r on the Turbo Pro 23s on my Roubaix. Sometimes lower. EDIT - I weigh about 170 lbs.

Another factor to consider is whether you ride light or heavy. Riders who stand up over RR crossings and rough spots, who know how to make a bike float over bumps, can go with lower pressure than those who keep their butts planted on the saddle in all situations.

Wanderer 05-13-14 10:47 AM

I run my Marathon Supremes at 92 PSI, (35s and 40s) because, for me, that's where they roll the best. Not 85, and not 95, but 92. Everyone is different in their wants and needs.

Retro Grouch 05-13-14 11:01 AM

Quote:

Originally Posted by Wanderer (Post 16754896)
I run my Marathon Supremes at 92 PSI, (35s and 40s) because, for me, that's where they roll the best. Not 85, and not 95, but 92. Everyone is different in their wants and needs.

I'm just the opposite.

Over the years I've slowly gravitated to using wider tires and less air pressure. The big "Aha" for me was when I went from using 120 psi to 100/110 psi with 28 mm tires on our tandem. We never pinch flatted, seemed to go about the same speed, but felt a lot smoother. I used to top up my tire pressure before every ride. Today I can't remember for sure the last time I pumped up my tires. I just squeeze them with my fingers and, if they don't feel "too" soft, I just ride. Subjectively I don't feel slower or that I'm having to work harder but, honestly, I don't fret about those things anymore.

fastcarbon 05-13-14 11:25 AM

I weigh 193 lbs. and am 71. I recently changed tire size of my GP4000s from 700x23 to 700x25. I used to run 110 rear and 100 fronts. I now run 105 rear and 95 fronts. I have never had a pinch flat on either size and have used these tires for better than 30,000 miles. They are ridden pretty hard with yesterdays ride hitting 45 mph. Some of the roads are fairly rough, especially on some mountain descents.

bruce19 05-13-14 12:06 PM

Don't know how this might fit in but I weigh 182 lbs and my bike weighs 18 lbs. I run 700X25 at 100 psi front and 110 psi rear. Rolls well and is comfortable.

JanMM 05-13-14 12:07 PM

I have bought into the 15% tire drop line of thinking (http://www.bikequarterly.com/images/TireDrop.pdf) and currently run my long wheelbase 'bent (30/70 Front/Rear weight) at 50/80 psi with 32 mm tires. Looking at the chart again, I could probably go lower at both ends. (225 lbs me+bike)


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