Tire pressure
#1
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Tire pressure
Hey y'all. I've been out of the cycling community for a while. I used to ride a lot about 10 years ago, but life happened and I had to hang up my cleats. I just recently purchased a "new" bike and began riding again. Recently I've been seeing articles online about lower pressure in your tires is better and can make you faster. I thought the school of thought was the more tire pressure, the less rolling resistance. Anyway, I run 25mm tires and found a calculator online that said the correct psi for my size and tire size is 94psi in the rear and 92 in the front. What tire pressure does everyone ride with and do you feel like a lower pressure makes you faster?
#2
Old guy on a bike
I like the Silca calculator and when I input all my info for my panaracer gravelking 32’s I got 67/64 front/rear
Then I measured the tires and they measure 36mm, and the calc changed to 55/53.
Takeaway is measure your tires if you want to use a calculator for pressure
Then I measured the tires and they measure 36mm, and the calc changed to 55/53.
Takeaway is measure your tires if you want to use a calculator for pressure
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#3
I get about the same for my 25 mm tires. Depends on your weight, surface conditions and speed.
More weight is more pressured, more speed is more pressure and better surface conditions is more pressure.
More weight is more pressured, more speed is more pressure and better surface conditions is more pressure.
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On my bikes that have clinchers, Gp4000s on one and Gp5000 on the other, both tires are 700x25. I inflate to 80 lbs. I way 240 lbs. I usually never have flats or other problems. On my newer bike that has tubeless tires (Schwable pro ones) 700 x 28 I inflate these to 65 lbs.
Hope that helps!
Hope that helps!
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I use the Silca calculator to find my ideal tire pressures, pump my tires up to 2-5 psi over those numbers...
and then use the thumb test to decide if I need to pump them up again in the next week or two.
and then use the thumb test to decide if I need to pump them up again in the next week or two.
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I just look at the sidewall of the tire and pump it up a little below the maximum pressure molded into the tire body. Currently alternating between two bicycles for daily road rides, running 700x32 and 700x35, and they get pumped up to about 75-80psi. I check it weekly and top off a necessary. No pinch flats, blow-outs, or other tire problems so it seems to be working.
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I just look at the sidewall of the tire and pump it up a little below the maximum pressure molded into the tire body. Currently alternating between two bicycles for daily road rides, running 700x32 and 700x35, and they get pumped up to about 75-80psi. I check it weekly and top off a necessary. No pinch flats, blow-outs, or other tire problems so it seems to be working.
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Hey y'all. I've been out of the cycling community for a while. I used to ride a lot about 10 years ago, but life happened and I had to hang up my cleats. I just recently purchased a "new" bike and began riding again. Recently I've been seeing articles online about lower pressure in your tires is better and can make you faster. I thought the school of thought was the more tire pressure, the less rolling resistance. Anyway, I run 25mm tires and found a calculator online that said the correct psi for my size and tire size is 94psi in the rear and 92 in the front. What tire pressure does everyone ride with and do you feel like a lower pressure makes you faster?
I like the Silca calculator and when I input all my info for my panaracer gravelking 32’s I got 67/64 front/rear
Then I measured the tires and they measure 36mm, and the calc changed to 55/53.
Takeaway is measure your tires if you want to use a calculator for pressure
Then I measured the tires and they measure 36mm, and the calc changed to 55/53.
Takeaway is measure your tires if you want to use a calculator for pressure
#9
Newbie
I'm on GP5000's 700x28 and run in the ballpark of 100psi for most rides (Trek Emonda SL5 with Alto 52mm deep carbon wheelset). I'm 295ish. For some reason, lower pressures make me worry about stress on the wheelset. Good luck!
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Yeah, there’s lots of talk about “lower pressures,” but few really understand the context and variables, or at least fail to articulate the complexities.
It used to be that even light riders and racers would run +100psi on the road in as skinny a tire as they could find, like 20mm or even 19mm. That’s the context.
Is that applicable to clydes? Maybe; what kind of tire and size? What kind of roads? What kind of riding? That’s the complexity, as also expressed well by mr_pedro above.
Without knowing the OP’s weight and answers to other questions, we cannot begin to comment on what an optimized for speed pressure might be.
I’m 245lbs and push 700x25 tubeless racing rubber aggressively, but with experience and care (i.e. I don’t ride heavy in the saddle and slam stuff) over rough MI roads. That works out to 95/100-105psi F/R for me, depending on the tires. I have no idea if it’s optimized for speed, but it is optimized for my preferred feel at the wheels, comfort, and damage resistance.
It used to be that even light riders and racers would run +100psi on the road in as skinny a tire as they could find, like 20mm or even 19mm. That’s the context.
Is that applicable to clydes? Maybe; what kind of tire and size? What kind of roads? What kind of riding? That’s the complexity, as also expressed well by mr_pedro above.
Without knowing the OP’s weight and answers to other questions, we cannot begin to comment on what an optimized for speed pressure might be.
I’m 245lbs and push 700x25 tubeless racing rubber aggressively, but with experience and care (i.e. I don’t ride heavy in the saddle and slam stuff) over rough MI roads. That works out to 95/100-105psi F/R for me, depending on the tires. I have no idea if it’s optimized for speed, but it is optimized for my preferred feel at the wheels, comfort, and damage resistance.
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Lower pressures in a 25mm tire will just lead to more pinch flats. If your bike has room for 32mm, try those and you will be able to lower pressure to the 60-80 psi range depending on your riding style.
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I'm ~210 and usually aim for 75-80 on my 28mm gp5000s. I've only pinch flatted my rear once... when I decided to test the lower limits and hit a bump at 55psi. So now I play it safe(r).
#13
Senior Member
25mm tires are pretty narrow, and narrow tires require higher pressure to avoid pinch flats. Also, insufficient pressure means the tire is compressing more than ideal and you lose energy to that flex. You might also notice 'squirming' or other undesirable handling traits with underinflated tires. So there are multiple reasons to continue to ride narrow or narrowish tires at high (~100psi or thereabouts) pressures.
Lower pressures are becoming more popular because many road bikes can accept fatter tires than in decades past - I have had more than one bike where 25mm seemed to be as wide as would fit, but I don't see my future self owning a bike that can't fit at least 32s.
So if sticking with 25mm tires, yeah, pressures in the 90s or 100s of psi are probably still a good idea. When you ride those tires enough to wear them out, see if you can fit wider tires for your next set and then enjoy the benefits of lower pressures. THere are many 'high-performance' (lightweight and light, supple casing) tires available in 28mm, perhaps fewer in 32mm, and only a few options above that. Lots of heavier and tougher tires in all sizes, but not so many 'fast' tires.
Lower pressures are becoming more popular because many road bikes can accept fatter tires than in decades past - I have had more than one bike where 25mm seemed to be as wide as would fit, but I don't see my future self owning a bike that can't fit at least 32s.
So if sticking with 25mm tires, yeah, pressures in the 90s or 100s of psi are probably still a good idea. When you ride those tires enough to wear them out, see if you can fit wider tires for your next set and then enjoy the benefits of lower pressures. THere are many 'high-performance' (lightweight and light, supple casing) tires available in 28mm, perhaps fewer in 32mm, and only a few options above that. Lots of heavier and tougher tires in all sizes, but not so many 'fast' tires.
#14
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I'm about 215 lbs, 6'2".
In p.s.i. front/rear, I run:
70/75 on 35mm clinchers,
80/85 on 28mm clinchers,
85/90 on 28mm sew-ups,
90/95 on 25mm clinchers,
95/100 on 23mm sew-ups.
In p.s.i. front/rear, I run:
70/75 on 35mm clinchers,
80/85 on 28mm clinchers,
85/90 on 28mm sew-ups,
90/95 on 25mm clinchers,
95/100 on 23mm sew-ups.
#15
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I look at the sidewall of the tire and go by that. Maximum PSI on the back and then I run about 4 PSI less on the front to get a better bit/traction. Also it’s more comfortable on the handlebar’s when riding on chip-seal.
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Jan Hein of the Bicycle Quarterly is the guy who has changed everyone's perception of tire sizes and pressures needed. It is interesting to read his scientific experiments that led to the bigger tires and less pressure. His evidence is so strong that the Tour de France riders are now riding bigger and bigger tires with less and less pressure. Jan's evidence shows that it is sidewall flex that determines how efficient a tire is to pedal and bigger is better in all cases. Pressure has a big role in this. He has experimented up to 50mm tires that role easier than 25mm tires at over 100psi. I have changed my tire pressure habits and now experiment with pressure to find the sweet spot for the tires I'm using. My smallest tire on a road bike is 32mm at this time and I'm very happy with them.
#17
Junior Member
The pressure should be sufficient that when sitting on the bike the tyre sidewall deflects around 15% to 20% of it's height.
The pressure needed varies according to tyre width, tyre wall suppleness and wheel load. So with identical tyres the front will always be a good but lower pressure than the rear.
https://www.renehersecycles.com/tire...ure-take-home/
So no hard and fast rules. Except possibly just pumping up to the max pressure on the sidewalk is probably wrong.
.
The pressure needed varies according to tyre width, tyre wall suppleness and wheel load. So with identical tyres the front will always be a good but lower pressure than the rear.
https://www.renehersecycles.com/tire...ure-take-home/
So no hard and fast rules. Except possibly just pumping up to the max pressure on the sidewalk is probably wrong.
.
#18
Junior Member
Jan Hein of the Bicycle Quarterly is the guy who has changed everyone's perception of tire sizes and pressures needed. It is interesting to read his scientific experiments that led to the bigger tires and less pressure. His evidence is so strong that the Tour de France riders are now riding bigger and bigger tires with less and less pressure. Jan's evidence shows that it is sidewall flex that determines how efficient a tire is to pedal and bigger is better in all cases. Pressure has a big role in this. He has experimented up to 50mm tires that role easier than 25mm tires at over 100psi. I have changed my tire pressure habits and now experiment with pressure to find the sweet spot for the tires I'm using. My smallest tire on a road bike is 32mm at this time and I'm very happy with them.
Last edited by Breadfan; 05-22-23 at 11:36 AM.
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Jan Hein of the Bicycle Quarterly is the guy who has changed everyone's perception of tire sizes and pressures needed. It is interesting to read his scientific experiments that led to the bigger tires and less pressure. His evidence is so strong that the Tour de France riders are now riding bigger and bigger tires with less and less pressure. Jan's evidence shows that it is sidewall flex that determines how efficient a tire is to pedal and bigger is better in all cases. Pressure has a big role in this. He has experimented up to 50mm tires that role easier than 25mm tires at over 100psi. I have changed my tire pressure habits and now experiment with pressure to find the sweet spot for the tires I'm using. My smallest tire on a road bike is 32mm at this time and I'm very happy with them.
#21
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Alan years ago I signed up for e-mail updates from the Bicycle Quarterly and it was through these e-mails that I learned of all the tests that Jan had been party too. Check out the Bicycle Quarterly web page. I believe it might be a paid subscription but their e-mails are free. I believe you get more information paying for it but that is how I found out about this interesting series of tire tests.
#22
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21 posts and 21 different techniques, approaches, opinions ... I don't know, that makes me kind of sad. I am not going to add to the confusion. I will simply suggest some consideration when presented with a commercial concern publishing material that stands decades of manufacturing and performance practice on its ear.
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Hey y'all. I've been out of the cycling community for a while. I used to ride a lot about 10 years ago, but life happened and I had to hang up my cleats. I just recently purchased a "new" bike and began riding again. Recently I've been seeing articles online about lower pressure in your tires is better and can make you faster. I thought the school of thought was the more tire pressure, the less rolling resistance. Anyway, I run 25mm tires and found a calculator online that said the correct psi for my size and tire size is 94psi in the rear and 92 in the front. What tire pressure does everyone ride with and do you feel like a lower pressure makes you faster?
The best advice I've heard (short of using a couple of up to date respected online calculators like Zipp and Silca) is to start at the lowest pressure you're comfortable with, then drop pressure a few psi at a time until you recognize you've gone too far. Do that, and you'll have a much better idea of what works for you.
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#24
I am on 35 mm tires, rated at 75 PSI. I fill them to 85 PSI, no problems at all.
I'm confused by the posts that say lower pressures go faster. Why? I'd think that with lower pressures, the tire will be less round and thus have more rolling resistance, no?
I'm confused by the posts that say lower pressures go faster. Why? I'd think that with lower pressures, the tire will be less round and thus have more rolling resistance, no?
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You might also want to google "contact patch" to see the differences between high and low pressure.
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Formerly fastest rider in the grupetto, currently slowest guy in the peloton
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