Tyre Blow Outs in Hot Weather

Philip Whiteman · Post by **Philip Whiteman** » 17 Jul 2013 12:49

A word of warning in hot weather:

Try to avoid pumping your tyres up to a maximum of 120PSI. Heat will increase the pressure in your tyre with the resultant risk of a tyre blow out. Couple the air temperature with braking and hot tarmac, that risk is increased yet further.

If you are storing your bike in a hot shed or leaving it inside a car, then consider releasing some of the air to reduce temperature.

Braking in hot weather may also be impeded with the infamous problem of reduced co-efficiency and molten rubber blocks. So, if taking a steep descent, pulse the brakes when braking and if necessary and when safe to do so, check the heat of your rims.

keith · Post by **keith** » 17 Jul 2013 23:42

Interesting we we having a conversation about this a work with one of the guys who plays squash. As you may know a squash ball is a bit dead until it has warmed up,presumably as the air pressure in side increases or the rubber gets softer ??.I don't play the game so I wouldn't know. Any Hoo I have not decreased tyre pressure during the heat wave ,but have thought a few times in the last couple of weeks, that my tyres feel a bit mushy. Could this be the affect of the rubber becoming softer in the heat ?.Not always on the same bike either,so not a slow.

slogfester · Post by **slogfester** » 09 Feb 2014 23:26

I was just looking through some old threads for winter tech advice and spotted this summer problem!

I have never known anyone in Oz decrease tyre pressure because of hot weather when riding. Even when its over 35oC

But we do deflate tyres in cars as a precaution because under the sun it can get >60oC inside a locked car.

When I played squash in the Pacific Islands we used to have special super-slow double yellow dot Dunlop balls. There was no such thing as a back wall dead ball. Flippin thing would keep high and bounce all over the place it was so hot.

Back to winter bicycle problems....

George · Post by **George** » 10 Feb 2014 09:08

I think weather-related issues are very unlikely. However, what I have seen is people whose tyres exploded due to rim overheating on descents in hot-weather continental sportives. Whether in a car or on a bike, never go down a mountain braking lightly all the way.

Andy Terry · Post by **Andy Terry** » 10 Feb 2014 09:31

George wrote:I think weather-related issues are very unlikely.

A temperature rise from 20C to 35C would put tyre pressure up from 120 to 126. Ye cannae change the laws o' physics.

George · Post by **George** » 10 Feb 2014 13:10

Andy Terry wrote:A temperature rise from 20C to 35C would put tyre pressure up from 120 to 126. Ye cannae change the laws o' physics.

I'm not disputing the laws of physics, Andy; what I'm disputing is their practical implications:
1. A temperature increase from 20C to 35C between the time you pump your tyres up and the time you ride your bike is a fairly unusual event, certainly in the UK.
2. Even if that unusual event occurs, a pressure increase of 5 or 6 psi is very unlikely to pop your tyres unless you are running them at or beyond the limit of their rated range (which includes a safety margin).

Andy Terry · Post by **Andy Terry** » 10 Feb 2014 14:48

George wrote:
Andy Terry wrote:A temperature rise from 20C to 35C would put tyre pressure up from 120 to 126. Ye cannae change the laws o' physics.
I'm not disputing the laws of physics, Andy; what I'm disputing is their practical implications:
1. A temperature increase from 20C to 35C between the time you pump your tyres up and the time you ride your bike is a fairly unusual event, certainly in the UK.
2. Even if that unusual event occurs, a pressure increase of 5 or 6 psi is very unlikely to pop your tyres unless you are running them at or beyond the limit of their rated range (which includes a safety margin).

George, I wasn't trying to argue, just putting a fact into the debate.

This thread reminds me of the other myth about having to deflate your tyres when taking a bike by plane.