Tyre Pressures

Shezzer

I've read a fair bit lately about tyre pressures and the difference in comfort / performance between 23mm and 25mm tyres. I'd always been lead to believe that lower tyre pressures are more comfortable BUT will increase rolling resistance and make you more vulnerable to punctures. On most of my training rides, I have my 23mm tyres inflated to around 100 psi.

My questions:

1) do lower pressures = more punctures?
2) what is the lowest tyre pressure (for 23mm or 25mm) that you would recommend?
3) are 25mm noticeably more comfortable than 23mm?

I'm interested in trying lower pressures and / or 25mm tyres to see how they affect comfort but don't want to go so low that the bike is dangerous or I have to stop every 3 miles to fix a flat.

Thanks in advance.

keef66

I got my first proper road bike in Sept last year; I was wanting comfort so specced 25's on it. Still don't have a track pump, but instead rely on using a Topeak road morph to top up the tyres occasionally. It has a rudimentary gauge, but can't read it without my reading specs which I rarely take with me. Last time I checked both tyres were down to 60 psi, so I pumped them up to 80 front and 90 rear. TBH i can't really tell the difference. Touch wood, no punctures despite the wild variations in tyre pressure. I only weigh 70kg wet through; YMMV.

Scrumple

I commute on mine, and Planet X suggested 110 psi when I bought it. They said the extra air would negate some of the pu*ct*re potential. Tyres are 23.

100 seems normal.

25 tyres are usually the winter bike choice, as the wider area is more grippy and less likely to damage due to the extra stuff between your rim and the road. Pay off is a reduction in speed as they are bigger etc.

Thats my lay person's understanding?!

Stone Glider

As it happens Cycling+ for May has a piece on "10 cycling myths". Number five is "harder is better". Nuff said

fossyant

Just run about 100/110 no more needed

Flasheart

I have Scwalbe Bizzard's (25mm) and I run them at 100psi . I do have a trackpump in the garage and check everytime before a ride.
The small stones "ping" off into the verges and not get stuck in my tires so that is good enough for me
Had one (mystery) flat so far. Nothing penetrated the tire, but there was a tiny pinhole in the tube....go figure :?
A kindly cyclist stopped to chat with me while I repaired it. He lent me his mini pump, which saved me using the CO2 thingy I had stashed in my saddlebag.

gabriel959

I run my tyres at the recommended PSI - in my case 125psi. May be a bit uncomfortable but I prefer so instead of running them at 100psi and getting a puncture (happened once!)

teagar

Stone Glider wrote:

As it happens Cycling+ for May has a piece on "10 cycling myths". Number five is "harder is better". Nuff said

What's the theory behind that?

roger_merriman

i cope fine with 20mm tires at 100PSI and i'm 14 stone or nr enought no pinch flats though the rough lanes, though with a rigid MTB background i ride light.

Stone Glider

@teagar The University of Texas tested four different tyre pressures with a panel of riders, "the real difference in rolling resistance........is too small to detect physiologically". Super-hard tyres can be a pain-in-the-@rse and shake the bike to bits too.

ohlala!

I weigh 85Kg and run 115 PSI on my Vittorias - they're 23 tyres. It's quite comfortable for me and goes over bumps soft and quickly. I think tyre pressure has to be matched with the rider's weight but usually minimum is 100 PSI.

doyler78

I always run my tyres at about 110psi + and I definitely feel the discomfort however on the up side I have never punctured.

Shezzer

Thanks for all the thoughts and advice folks.

I'm happy enough tootling along at 100psi for training and 130psi for racing but I was curious what the lowest pressure is that you've tried or would recommend. I've got a couple of long events coming up and wondered if lowering my pressures to around 80psi on a 23mm would drastically increase comfort. I guess I could just lower the pressures and give it a go but I'm keen to avoid puncturing or going 'wobbly' on tight corners.

Also, did anyone who switched from 23mm to 25mm notice a significant difference in comfort levels?

EDIT
I weigh 11st 5lb if that makes a difference.

il_principe

I run 23's @ 120psi. Can be a bit jarring on poor road surface but I can live with that.

redddraggon

I run 80psi front 100psi rear. And I never get pinch flat. Running my tyres at well over 100psi gives me a numb bum and hands and lowers the grip in the wet.

Jeez no wonder people complain of road buzz if they pump their tyres up to what it says on the tyre - just because it says 120 on the tyre it doesn't mean you have to do it.

teagar

Stone Glider wrote:

@teagar The University of Texas tested four different tyre pressures with a panel of riders, "the real difference in rolling resistance........is too small to detect physiologically". Super-hard tyres can be a pain-in-the-@rse and shake the bike to bits too.

So the resistance difference is negligable, but the difference in level of comfort isn't?

Fair enough.

I've always just thought people need to strap on a pair when they complain about road buzz or poor road quality. In fact, I still think that!

Philip S

I normally run on 100-110 psi, but recently had my bike serviced at the LBS and it feels like they pumped the tyres up higher to c120psi. That may be good on a decent, smooth surface but it seems to be a little too high for the roads I cycle on as it almost feels like the wheels are bouncing along rather than rolling.

GavH

My cheapo Vittoria Rubino 23s say min 100, max 150 psi on them. I run them about 120 and whilst you do feel some bumps in the road, I reckon you'd still feel them at 100 but the bike just feels a bit better at 120.
I once went out on my old bike with 25s on and wondered why it felt so sluggish yet comfortable, only to get home and check the pressures (yes I knoiw, a bit late then) - it had 60 psi in the rear and whilst it was comfy in terms of lack of buzz and bumps, it didn't half feel harder on the legs as usual!

Feltup

I weigh 60kgs and run my 23's at 100 front 110 back in the dry and 90 front 95 back in the wet. I ride pretty rough roads including some harsh cattle grids and have not had a pinch puncture yet but have had a couple of thorns and one flint slice the sidewall. Not too bad for a couple of thousand miles on this set Rubino Pros.

Monty Dog

The pressure on the side of the tyre is the maximum, not the recommended. IME hard tyres 'bounce' more, transmit road buzz and are more puncture prone - try sticking a pin in a semi-deflated balloon vs a full one to understand. In terms of minimum pressures, it's enough to stop snakebites and can be as low as 5-6 bar with fatter tyres for my weight. I remember talking to a pro mechanic about racing in Belgium - he laughed at the UK riders who whack the tyres up rock hard, get punctures all the time and skid about in the wet on skinny tyres whereas the team was running 25mm tyres at no more than 6 bars - particularly important on wet cobbles. I've probably relayed this experience for as long as I've been a forum member and stiff chuckle at people who insist on 20mm tyres at 8 bar is what you need to go fast!

JGS

I've recently swapped from my usual "pump them up to the max + 10%" method of inflating tyres to using the tyre chart here: http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3802

Make sure you weigh yourself in your typical cycling gear and holding your bike at a typical time of day you'd cycle. I've found that since using their recommendations for smoothish roads that I don't go any slower at all, but nearly all the road buzz is cancelled out and I find I have a bit more traction in corners on my GP4000s 23mm tyres.

dizzydane

Shezzer wrote:

Thanks for all the thoughts and advice folks.

Also, did anyone who switched from 23mm to 25mm notice a significant difference in comfort levels?

EDIT
I weigh 11st 5lb if that makes a difference.

I ride 23's at 100psi in the summer and 25's at about 80 to 90psi in the winter.

It feels like I cruise faster on the downhill’s on the 23's but the 25's are slightly more comfortable for longer rides.

(And I've had less punctures on the 25's at a lower psi...)

karlmoreton

Ride with vittoria open pro and michelin pro race, tend to run both of these at 92 psi front 98 psi rear but that is with a topeak digital pressure gauge which is a lot more accurate than most track pump gauges. Don't seem to get many if any p***t***s.

For TT events it is 145psi on 20mm Veloflex Records, its all about suffering, they make me cry like a baby , but it feels fast ! :twisted:

W5454

Monty Dog wrote:

The pressure on the side of the tyre is the maximum, not the recommended. IME hard tyres 'bounce' more, transmit road buzz and are more puncture prone - try sticking a pin in a semi-deflated balloon vs a full one to understand. In terms of minimum pressures, it's enough to stop snakebites and can be as low as 5-6 bar with fatter tyres for my weight. I remember talking to a pro mechanic about racing in Belgium - he laughed at the UK riders who whack the tyres up rock hard, get punctures all the time and skid about in the wet on skinny tyres whereas the team was running 25mm tyres at no more than 6 bars - particularly important on wet cobbles. I've probably relayed this experience for as long as I've been a forum member and stiff chuckle at people who insist on 20mm tyres at 8 bar is what you need to go fast!

+1
I run 80psi front and rear on 700 x 23s and find this perfect for comfort,absorbing bumps without compromising speed.Can't believe how many idiots run 100+psi then complain about discomfort.

doyler78

W5454 wrote:

Monty Dog wrote:

The pressure on the side of the tyre is the maximum, not the recommended. IME hard tyres 'bounce' more, transmit road buzz and are more puncture prone - try sticking a pin in a semi-deflated balloon vs a full one to understand. In terms of minimum pressures, it's enough to stop snakebites and can be as low as 5-6 bar with fatter tyres for my weight. I remember talking to a pro mechanic about racing in Belgium - he laughed at the UK riders who whack the tyres up rock hard, get punctures all the time and skid about in the wet on skinny tyres whereas the team was running 25mm tyres at no more than 6 bars - particularly important on wet cobbles. I've probably relayed this experience for as long as I've been a forum member and stiff chuckle at people who insist on 20mm tyres at 8 bar is what you need to go fast!

+1
I run 80psi front and rear on 700 x 23s and find this perfect for comfort,absorbing bumps without compromising speed.Can't believe how many idiots run 100+psi then complain about discomfort.

Perhaps you should start a campaign asking manufacturers not to recommend idiot tyre pressures. Seems a bit rich to blame the consumer for following manufacturer guidance but then it's one of those things that cyclists are just supposed to know just because they choose to swing a leg over a top tube.

rally200

My Spec & schwalbe tyres both carry recommended pressure ranges rather than maximums. Contis show a max.

I've been using 110 -120 lb in 23s, but at the weekend had a back wheel puncture 15 miles from home, was more than happy with the pressure I got out of my new mini-pump - checked it at home with track pump -was only 90lb - makes me wonder now about going 110lb+ (but I am only about 150lb)

Stone Glider

If you weigh less surely, you can get away with a lower pressure in the tyre and still avoid "snake bite"?

Another bloody advantage for the weight weenies. It's not fair! :evil:

doyler78

Stone Glider wrote:

If you weigh less surely, you can get away with a lower pressure in the tyre and still avoid "snake bite"?

Another bloody advantage for the weight weenies. It's not fair! :evil:

Yep certainly seems that way however even if you look at the recommended tyre pressure on a Michelin Pro3 Race tyre the nice little chart would suggest that 87psi (slightly higher than the previously recommended by the non idiot) you should weigh 50kg or less.

I don't doubt what they are saying is right however I think also that a lot of people can ride pressures in excess of 100 psi and still have a comfortable ride. I unfortunately suffer at present however I have used pressures in excess of 110 psi for 4 years previous to that without problem so I guess other factors are at play here. Perhaps some people's problems isn't their high pressure but their poor bike fit.

oldwelshman

Shezzer wrote:

Thanks for all the thoughts and advice folks.

I'm happy enough tootling along at 100psi for training and 130psi for racing but I was curious what the lowest pressure is that you've tried or would recommend. I've got a couple of long events coming up and wondered if lowering my pressures to around 80psi on a 23mm would drastically increase comfort. I guess I could just lower the pressures and give it a go but I'm keen to avoid puncturing or going 'wobbly' on tight corners.

Also, did anyone who switched from 23mm to 25mm notice a significant difference in comfort levels?

EDIT
I weigh 11st 5lb if that makes a difference.

So why do you pump them to 130 for a race?
I agree with Monty's comments.
I run mine at 100psi in summer and about 80 to 90 in winter.
For track 120.

Shezzer

oldwelshman wrote:

So why do you pump them to 130 for a race?

Same reason as most people I guess. Cos my races tend to be shorter distance and I can put up with a little discomfort if it means I may be slightly quicker. I don't know if it actually makes me any quicker but it just feels fast.

For training I often do longer mileage and comfort is more important hence lower pressures.

Thanks again everyone for your thoughts. Will be trying lower pressures on my next few training rides ... just gotta shift this stinking cold first.

oldwelshman

Shezzer wrote:

oldwelshman wrote:

So why do you pump them to 130 for a race?

Same reason as most people I guess. Cos my races tend to be shorter distance and I can put up with a little discomfort if it means I may be slightly quicker. I don't know if it actually makes me any quicker but it just feels fast.

For training I often do longer mileage and comfort is more important hence lower pressures.

Thanks again everyone for your thoughts. Will be trying lower pressures on my next few training rides ... just gotta shift this stinking cold first.

Despite all the research theres no evidence at all to indicate that much higher pressure reduce rolling friction thus increasing speed