Tyre pressures and rider weight

[lulubel]

I know that how hard you need to run your tyres to prevent pinch flats is affected by rider weight - heavier riders need to run tyres at higher pressures.

As a very light rider (just over 7 stone), I should be able to run my tyres pretty soft. I do run them very soft on my mountain bike, but I'm not so sure what to do on the road bike.

If my tyres are rated 100psi min - 130psi max, I take this to mean I shouldn't be running them at less than 100psi. But can I ignore that because I'm a very light rider, and run them at 80 or 90psi? Will running them below the manufacturer's recommended minimum affect the overall puncture resistance of the tyres? (I try to use the best puncture resistant tyres I can without them weighing half a ton.)

 

[Sittingduck]

Trial & error? I would think 90-100 is about right... give it a go.

 

[HLaB]

I've not weighed my self in ages (I usually vary between 9.5 and 10 stone) but I can comfortably run my tyres between 80-90psi no problem and it feels grippier in the wet/ice (we get a lot of that), the ride is marginally better too and I don't notice any decrease in speed (increase in resistance). Somebody posted a good guide a wile back on weight/psi.

 

[HovR]

I weigh a tad less than HLaB and also currently run my tires at around 90psi. Haven't had any punctures in around 2k miles, so I doubt you'll have any issues around 80 to 90 psi. Maybe try a different pressure each day/week until you find the correct balance of speed and comfort for you.

 

[Hacienda71]

I am 12.5 stone, run my pro4 service course at 115psi. Hit a pothole this morning, pinch puncture. Pumped the new tube upto 60 psi and rode three miles back home to top up with the track pump. I didn't notice any huge difference in handling or speed. It was the front tyre so less likely to see any side effects. There is a school of thought that runing your tyres at a slightly lower pressure is better.

 

[festival]

Current thinking is to run slightly softer than minimum for better control and grip without losing speed.
Therefore 90/95 psi maybe beneficial for you, of course that's dependent on road conditions, riding style, quality and profile of tyres and wheels etc,
e.g. a 700 x 24 at 95 psi can have less rolling resistance and have excellent grip as opposed to a 700 x 19 at 120psi

 

[snailracer]

http://www.dorkypantsr.us/bike-tire-pressure-calculator.html

 

[Boon 51]

My road bike should be 120 psi but it was rock hard and evey bump I went over made the bike shudder, so I let some out and I checked it by just pressing the tyre with my fingers.. but it took 3 attempts of letting air out to get the right feel but I am guessing I'm running about 90 front and 100 rear..
Cant give you an exact psi as I've not got a proper pump yet as I'm waiting for father christmas.. who might be along shortly..
But let a little air out and see how you go the worst that could happen it you have to pump it up a bit...
I'm not that weighty I'm only 10st 7lbs ish..

 

[black'n'yellow]

If my tyres are rated 100psi min - 130psi max, I take this to mean I shouldn't be running them at less than 100psi. But can I ignore that because I'm a very light rider, and run them at 80 or 90psi?

I'm currently 67kg and use pressures of around 80psi on the road at the moment. I've not seen a tyre with a 'minimum' pressure rating - not sure why that would be necessary.

 

[snailracer]

I'm currently 67kg and use pressures of around 80psi on the road at the moment. I've not seen a tyre with a 'minimum' pressure rating - not sure why that would be necessary.

Some tyres do have minimum recommended pressures marked on them - it's to stop them slipping off the wheel when going around bends. That said, many tyres don't, and there is such a huge margin of safety that a lightweight rider could probably underinflate without too much risk.

 

[lulubel]

I'm currently 67kg and use pressures of around 80psi on the road at the moment. I've not seen a tyre with a 'minimum' pressure rating - not sure why that would be necessary.

I've seen it on a few MTB tyres, and it's also on Vittoria Rubino Pros. They're the ones I was referring to when I quoted 100 min and 130 max. They're marketed as puncture resistant, so I think 100 is the minimum they recommend for all the puncture resistant features to work properly.

The reason I asked the question is because I changed to wider tyres after spending some time MTBing and getting used to the comfort of wider, softer tyres. I'm now using Vittoria Randonneur hyper, which are 32mm, but only about 80g heavier than the 25mm Rubino Pros. They're also 120tpi as opposed to the Rubino Pros 150tpi, but they're still marketed as puncture resistant. I was a bit shocked to get a puncture yesterday - a piece of glass worked its way through the casing - less than a month after starting using them, so I'm considering my options. I'll stick with them for now, because it could have been just bad luck, and it was quite a big piece of glass. But I never had a puncture with Rubino Pros (in over 4 years of using them), so if the Randonneurs don't work out, I think I'll be going back to them. I've never run them at less than 100psi, but would obviously like to, so I wondered what other people's thoughts on minimum pressures were.

 

[Hacienda71]

The minimum suggested pressure on the Pro4 tyre wall is 87psi to a max of 116psi. Can't see it being a problem if they were run at less than this.

 

[HovR]

I wouldn't have thought that running a tire slightly soft would increase the risk of punctures from sharp objects poking through the tire. If anything I would have thought that this would be reduced as the tire will put less pressure on the sharp object and conform over it to a greater extent when the tire is slightly soft, although this is only my own theory, so could be incorrect.

Obviously though you'll increase the risk of pinch punctures when hitting potholes etc.

 

[Cycleops]

Always worth just running a gloved hand over the tyres after a run to remove any debris that might work it's way into the tyre over time.

 

[Bigsharn]

I weigh over 20 stone, and have a set of Marathon + at 120psi (rated for 110). Seems to hold me fine.