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Discussion Starter · #1 ·
Would it make sense to drop tire pressure while riding in the rain? Normally run about 120psig in dry weather.
 

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take it down up to 30psi depending on conditions. I recently slid out on a well known descent b/c of running 120psi. it was also insanely muddy, wet and off camber, but still. I felt like an idiot. and it hurt.
 

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yes, lower in the wet.

that said, unless you are a clyde and/or on 20c tires, lower in the dry as well.

at 175lbs, i run ~100psi in 23c open corsas. sidewall says 8-10 bar (116-145psi)! i used to be a pumped-to-the-max kinda guy until somebody clued me in. the benefits of lower psi? better wear, better grip, better comfort. no perceivable increase in rolling resistance either.

really. try it for a ride or two. you can always jack 'em up again, but i'm betting you won't.
 

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dookie said:
yes, lower in the wet.

that said, unless you are a clyde and/or on 20c tires, lower in the dry as well.

at 175lbs, i run ~100psi in 23c open corsas. sidewall says 8-10 bar (116-145psi)! i used to be a pumped-to-the-max kinda guy until somebody clued me in. the benefits of lower psi? better wear, better grip, better comfort. no perceivable increase in rolling resistance either.

really. try it for a ride or two. you can always jack 'em up again, but i'm betting you won't.
Hey dookie:
My history is similar to yours but different ending. I'm 185 and ride my 23's at 130 psi and have for years. I know everyone says it is better to use a lower psi and I have really tried to do that, but every time I try the lower pressures, it 'feels' odd, strange, spooky, to me, and after a while I go back to the high pressure. I don't race anymore, and just do fast flat training rides. Any advice on how to change? I feel like an addict hooked on 'High-Pressure' that I know isn't good for the body or the bike and certainly isn't needed to ride fast. Help me!!:D
John
 

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jmlapoint said:
Hey dookie:
My history is similar to yours but different ending. I'm 185 and ride my 23's at 130 psi and have for years. I know everyone says it is better to use a lower psi and I have really tried to do that, but every time I try the lower pressures, it 'feels' odd, strange, spooky, to me, and after a while I go back to the high pressure. I don't race anymore, and just do fast flat training rides. Any advice on how to change? I feel like an addict hooked on 'High-Pressure' that I know isn't good for the body or the bike and certainly isn't needed to ride fast. Help me!!:D
John
lower 'em down 5-10 psi for a few rides, then drop 'em down again. it really is better. i'm 165 and ride hutchinson road tubeless at 85/80. wouldn't ever go back. ride my road tubulars at 95/90. or...try some cx tubulars at 25psi, then nothing will feel weird.

and why is it that all these tire pressure questions are posted here, and not in the wheels/tires forum?
 

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cxwrench;
Thanks for your input on Tire Pressure.
I will start tomorrow and see how it goes with 5-10 reduction in psi as you recommend.

You are right. This probably should be in Wheels/Tire Forum, and I apologize for my 'Thread Heist', but I couldn't resist asking.
Thanks.
John
 

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lemme know how it goes...but i'll bet dropping the pressure down a bit at a time will make it a bunch easier and less 'weird'. try the road tubeless thing, too. the stans kit w/ hutchinson tires and the sealant is pretty cool. i've got a few hundred miles on the tires and there is virtually no wear on the rear tire. they seat really quickly (could probably use a floor pump) and ride great.
 

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Mistrust your feelings

jmlapoint said:
I'm 185 and ride my 23's at 130 psi and have for years. I know everyone says it is better to use a lower psi and I have really tried to do that, but every time I try the lower pressures, it 'feels' odd, strange, spooky, to me, and after a while I go back to the high pressure. I don't race anymore, and just do fast flat training rides. Any advice on how to change? I feel like an addict hooked on 'High-Pressure' that I know isn't good for the body or the bike and certainly isn't needed to ride fast.
MAVIC did testing of riders "feelings" about wheel stiffness and their data show that people cannot reliably tell which wheels are which. Bicycle Quarterly asked their testers to tell them which tires were fastest in their roll down tests. Riders could not predict which tires were faster.

You are simply wedded to the idea that a harsher ride must be a faster ride. It's not true. Get over it and let data triumph over intuition. The data show that anything beyond 110 psi just decreases traction, speeds tire wear, and is uncomfortable, but it is NOT faster.
 

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Kerry Irons said:
MAVIC did testing of riders "feelings" about wheel stiffness and their data show that people cannot reliably tell which wheels are which. Bicycle Quarterly asked their testers to tell them which tires were fastest in their roll down tests. Riders could not predict which tires were faster.

You are simply wedded to the idea that a harsher ride must be a faster ride. It's not true. Get over it and let data triumph over intuition. The data show that anything beyond 110 psi just decreases traction, speeds tire wear, and is uncomfortable, but it is NOT faster.
This advice was the best I've seen on this website about anything, I think I told you that a few months ago.

I'm riding GP 4000s 25's at around 90psi give or take, at 175lbs bodyweight and I can't imagine riding 23's again at 105 to 110 psi. The difference dropping the 23's to around 100psi was an epiphany.

I've had about 1 flat in the last 6 months and that was a tiny puncture from a steel splinter.
 

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Hum, when I raced cars we increased the tire pressure when it rained. It narrowed the contact patch of the tire putting more pressure on the road and got the tire rubber warmer.
 

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Wow... you need to get to 25's, you'll get less pinch flats. Bicycles can't hydroplane, so you really want to keep your pressure where you normally would. There's a lot of myths about pressure and wet roads for cycling. If you lower your pressure, at your weight, you'll get a LOT of flats. Now if you were running 25's, then you could drop to 80psi. I tried 23's for a little while and got too many flats, so I went back to 25's.
 

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jmess said:
Hum, when I raced cars we increased the tire pressure when it rained. It narrowed the contact patch of the tire putting more pressure on the road and got the tire rubber warmer.
3000lbs on 50in^2 of rubber is a world away from 200lbs on 2in^2. maybe?
 

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the simple rule of thumb I use is to set your psi so that each tire's contact patch is about one square inch.

this is easy math:
bike+rider = 200 lbs
front/rear = 55/45
.55x200 = 110 rear psi
.45x200 = 90 front psi

If your math works out to a rear psi higher than 110 or so, it means you need bigger tires.
 

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Creakyknees said:
the simple rule of thumb I use is to set your psi so that each tire's contact patch is about one square inch.

this is easy math:
bike+rider = 200 lbs
front/rear = 55/45
.55x200 = 110 rear psi
.45x200 = 90 front psi

If your math works out to a rear psi higher than 110 or so, it means you need bigger tires.
I don't like your rule, Creak, because if fails to take account of tire size. If that big guy (say bike+rider=250 lb) does the math and comes up with a big number (137 psi), and then switches to a bigger tire, your rule will still tell him to use 137 psi. Bigger tires for bigger weights should have a bigger contact patch.

Your rule gets pretty good results for a 23mm tire, but you need another term to allow for other tire sizes. Get on it.
 

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Discussion Starter · #17 ·
25's...

Peanya said:
Wow... you need to get to 25's, you'll get less pinch flats. Bicycles can't hydroplane, so you really want to keep your pressure where you normally would. There's a lot of myths about pressure and wet roads for cycling. If you lower your pressure, at your weight, you'll get a LOT of flats. Now if you were running 25's, then you could drop to 80psi. I tried 23's for a little while and got too many flats, so I went back to 25's.
Feel sloppy to me...and they rub my 3T fork. I prefer 23's.
 

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Creakyknees said:
the simple rule of thumb I use is to set your psi so that each tire's contact patch is about one square inch.

this is easy math:
bike+rider = 200 lbs
front/rear = 55/45
.55x200 = 110 rear psi
.45x200 = 90 front psi

If your math works out to a rear psi higher than 110 or so, it means you need bigger tires.

Waiiit, are you saying I should run 62 front PSI?
 

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MCF said:
I am about 205lbs and run 23's....say 100lbs or go 110lbs?
That'll probably work if you are at all reasonable about missing potholes.

Better will be to run good 25's. Do it once and you'll never go back.
 

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Argentius said:
Waiiit, are you saying I should run 62 front PSI?
Are you saying you weigh 120 pounds and ride an 18-pound bike?

Wait for me at the top of the hill, okay?

You're the guy that can get away with the 20mm tires.
 
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