Tyre Temperatures

Nelly · Jun 15, 2011

I was wondering about this the other day.
Some of you guys ride in really hot conditions which obviously allows the air in your tyres to expand quicker.
Do any of you hotter weather guys take out air off the standard setting to allow for this?

Paradoxically most of my riding is done in much cooler conditions. Should I over-inflate the tyre by a few PSI to achieve the best possible performance?

Just wondering.

Nelly:thumbup:

rino60 · Jun 15, 2011

I've never deflated my tyres much - I simply assumed that as I ride in an allowable range for the tyres specs, that my PSI would be at least 95% of the optimum value

Erci · Jun 15, 2011

I'm no expert, but I would say overinflating tires in cold conditions is a bad idea. Higher pressure = less grip. I've always stuck to spec and it's worked very well for me, in all temps.

rino60 · Jun 15, 2011

Erci said:
I'm no expert, but I would say overinflating tires in cold conditions is a bad idea. Higher pressure = less grip. I've always stuck to spec and it's worked very well for me, in all temps.

And he wears a beanie! Listen to 'the man'

rino60 · Jun 15, 2011

But, he makes a good point. While temperature is directly related to pressure for a given volume of air, if you do fill your tyres up while they're cold, in snowy weather, the recommended PSI will suffice for any vehicle.

In the cold, the same pressure will have a corresponding higher volume of air - if you were riding from cold to warm, I would deflate slightly, and the same in reverse. But I WOULD fill to stock - a difference in temperature will purely mean a different volume of air at the same pressure.

Norbert · Jun 15, 2011

Nelly said:
I was wondering about this the other day.
Some of you guys ride in really hot conditions which obviously allows the air in your tyres to expand quicker.
Do any of you hotter weather guys take out air off the standard setting to allow for this?

Paradoxically most of my riding is done in much cooler conditions. Should I over-inflate the tyre by a few PSI to achieve the best possible performance?

Just wondering.

Nelly:thumbup:

it's a bit more complicated than that.

in hot weather for aggressive riding you lower your tire pressure so that the heat doesn't dissipate to the tire rim, the tire gets hotter and stickier. There are tires designed to get stickier than others when hot. Pilot Power (sport) v Pilot Roads (sport touring), for example.

in hot weather for touring you inflate to the max in the manual 36/42.
you are concerned with tread wear and you want the heat to dissipate to the rim. plus, you probably have additional weight with luggage.

in cold weather you can lower your tire pressure by 3 psi, but no less than 30psi. I normally run 33/36 and i sometimes go 30/33psi.
in cold weather touring, however, i would run 33/36.
i wouldn't do any aggressive stuff when it's cold.
By cold I mean about 50F or less.....I've commuted down to 20F with 30/33psi. All backroads....probably average 40-45mph.

Check your tire pressure religiously. If you are going through different temperatures throughout the day, remember that a change in 10F is about 1 psi. So if you want 42psi when it's 60F out, and you know it's going to be 70F out, put in 41psi. In reality the 10 degree diff isn't going to be a big deal. If it's a 30 degree diff in temp it's more significant.

Some of the track junkies on this forum would know more than me.
I've done a lot of touring so I know a bit about preserving tire tread.

rino60 · Jun 15, 2011

OMG_WTF said:
it's a bit more complicated than that.

in hot weather for aggressive riding you lower your tire pressure so that the heat doesn't dissipate to the tire rim, the tire gets hotter and stickier. There are tires designed to get stickier than others when hot. Pilot Power (sport) v Pilot Roads (sport touring), for example.

in hot weather for touring you inflate to the max in the manual 36/42.
you are concerned with tread wear and you want the heat to dissipate to the rim. plus, you probably have additional weight with luggage.

in cold weather you can lower your tire pressure by 3 psi, but no less than 30psi. I normally run 33/36 and i sometimes go 30/33psi.
in cold weather touring, however, i would run 33/36.
i wouldn't do any aggressive stuff when it's cold.
By cold I mean about 50F or less.....I've commuted down to 20F with 30/33psi. All backroads....probably average 40-45mph.

Check your tire pressure religiously. If you are going through different temperatures throughout the day, remember that a change in 10F is about 1 psi. So if you want 42psi when it's 60F out, and you know it's going to be 70F out, put in 41psi. In reality the 10 degree diff isn't going to be a big deal. If it's a 30 degree diff in temp it's more significant.

Some of the track junkies on this forum would know more than me.
I've done a lot of touring so I know a bit about preserving tire tread.

I'm not sure if i am interpreting you correctly, and i don't know a whole lot about racing OR touring, but... Ignoring the elastic limitations of the tyre, as it would only make a small amount of difference. The ideal gas law states that PV=nRT, where n is simply the molecular amount of the material, and R is a gas constant depending on the units. So we can see that if we fix a certain volume (and thus a certain molecular volume) that P is proportional to T. Therefore an increase in temperature will increase pressure.

So what I say is that if you want 42PSI at 60, wouldn't you put in 43PSI at 70? Or am I completely misunderstanding you and the physics of a tyre (a good possibility).

Norbert · Jun 15, 2011

if it's 90f outside and it stays around 90f, i wouldn't take air out.
keep it at 33/36 or 36/42.

if you're doing a track day that's a whole different thing......

Ben_H · Jun 15, 2011

You could just fill your tires with nitrogen it does not expand with temperature. Also pressure would only change by about 10% with temperature.

ozzieboy · Jun 15, 2011

For the purposes of grip, you want the rubber to reach the optimum temp, and around the right rigidity for stability.

If you let air out you will end up with the tyre flexing more, and this will generate heat in the rubber. If you let too much out, you lose stability, and can overheat the tyre. On a hot day the rubber gets more heat from the road, but less heat from flexing, so you will actually want to let some air out if it's grip you're after.

For the purposes of wear, you will want to keep the pressure up to a certain level in all conditions. On warm days it will be stickier, than on cold days, but you will get better mileage from the tyres.

It all depends what you want.

Also (to further complicate things) some tyres have a stiffer carcass than others, as they are meant to run with a lower pressure in them, and are stiffer to help maintain stability. Some of these tyres are actually hard work to keep up to temp on the road.

Another option for tyre pressures is to go for a ride at an ambient temperature and pressure you are happy with and get the tyres warm. Then measure the pressure, and from then on check the pressures warm. This is handy if you don't have a compressor at home, and have to ride the bike somewhere before checking and adjusting it.:thumbup:

Norbert · Jun 19, 2011

my f800gs owners manual gives the tire temps at 68F.
interesting.
i still won't change the tire pressure configurations i run.....

rsw81 · Jun 19, 2011

Ben_H said:
You could just fill your tires with nitrogen it does not expand with temperature. Also pressure would only change by about 10% with temperature.

I'm sorry Ben, but this is not true. Nitrogen gas still follows the same basic properties of physics that all other gases follow. The reason people use Nitrogen instead of atmospheric air is because of the moisture in the air, not it's ability to expand/contract. The issue with atmospheric air is that it can condensate or even freeze in cooler temperatures. Nitrogen, having no oxygen or hydrogen in it, will not do this.

Norbert · Jun 19, 2011

rsw81 said:
I'm sorry Ben, but this is not true. Nitrogen gas still follows the same basic properties of physics that all other gases follow. The reason people use Nitrogen instead of atmospheric air is because of the moisture in the air, not it's ability to expand/contract. The issue with atmospheric air is that it can condensate or even freeze in cooler temperatures. Nitrogen, having no oxygen or hydrogen in it, will not do this.

so does nitrogen reduce the fluctuations in tire pressure with the ambient temperature?
i was thinking that it would be a good idea fill the tires up with nitrogen on a cross country trip.....

iSteve · Jun 19, 2011

rsw81 said:
I'm sorry Ben, but this is not true. Nitrogen gas still follows the same basic properties of physics that all other gases follow. The reason people use Nitrogen instead of atmospheric air is because of the moisture in the air, not it's ability to expand/contract. The issue with atmospheric air is that it can condensate or even freeze in cooler temperatures. Nitrogen, having no oxygen or hydrogen in it, will not do this.

I think both you and ben are right. They use nitrogen because it expansion at a constant rate. Where air expansion will change with weather conditions.

Norbert · Jun 19, 2011

does it make a big difference? maybe i should ask some iron butt folks....
air is almost 80% nitrogen anyways....

iSteve said:
I think both you and ben are right. They use nitrogen because it expansion at a constant rate. Where air expansion will change with weather conditions.

rsw81 · Jun 19, 2011

iSteve said:
I think both you and ben are right. They use nitrogen because it expansion at a constant rate. Where air expansion will change with weather conditions.

This is a very accurate statement. The reason for this is what I was mentioning before with the moisture in the air. The issue is that there are actual liquid particles aerosolized in atmospheric air that causes the non-linear expansion rates with temperature change.

iSteve · Jun 19, 2011

I don't know if it makes that big a differences with normal street riding with good street tires. But if your local shop has nitrogen it won't hurt. I also was told a long time ago that nitrogen molecules are large and will not dissipate through rubber so the pressure stays more constant over time.

rsw81 · Jun 19, 2011

iSteve said:
I also was told a long time ago that nitrogen molecules are large and will not dissipate through rubber so the pressure stays more constant over time.

Nitrogen and Oxygen are virtually the same size molecules, given that they sit literally right next to each other on the periodic table. It has more to do with its physical properties (ie: temperature and pressure at which it will go from a gas to a liquid or solid). Even in liquid form, Nitrogen is much more gaseous than Oxygen. Additionally, when combined with hydrogen, it is still more gaseous (think of Ammonia vs Water).

Tyre Temperatures

International Liaison

Junior Member

Howie Mandel's evil twin

Junior Member

Junior Member

crash tested

Junior Member

crash tested

Junior Member

Avid 4WD Hunter

crash tested

Keep it Kosher

crash tested

Junior Member

crash tested

Keep it Kosher

Junior Member

Keep it Kosher

Similar threads