Another Tyre thread...

robin7 · 9 Jun 2015 at 11:01

Couldn't find quite what I was looking for with a search so thought I'd ask.

Probably a stupid question but I'm a noob at this:

Does local temperature change tyre pressure at all?

Ie. My 2012 CBR600F states 36 front and 42 rear. This is for one rider, OR for rider+Pillion full loaded (has the same pressure in both boxes in the manual).

How much of a blanket statement is this? I found when my pressures were newly done it wasn't that nice, and as they deflated a bit it was nicer... and then got crappy again when they were edging towards too low.

I'm guessing this is a stupid question, but I know that on a track the temps change quite drastically. So I would have thought that as I live in Gibraltar and most of my riding is done in Spain it might make a difference? If air temp is 30 degrees +, then the road temp must be hotter, so a long journey through some nice twisties would heat them up quite a lot I would think?

Just interested in opinions? And yes I am running on the recommended pressures

Felix · 9 Jun 2015 at 11:12

I always thought higher temps would mean higher pressure. So if checking your tyres when cold, by the time they have heated up they could be a few PSI higher. Which may explain why if you put them at the recommended they don't feel "nice".

Kreeeee · 9 Jun 2015 at 11:20

Yes it does.

Both the ambient temperature and altitudes here have a considerable effect on my "cold" tyre pressures.

If I'm off to the mountain passes I need to change what I put in my tyres compared to riding by the sun kissed lakes or it feels like I'm riding on ice.

wazza300 · 9 Jun 2015 at 11:26

I just stick 30 psi each in mine,any higher feels to hard on the road

robin7 · 9 Jun 2015 at 12:36

Cool might try it next time I go for a long ride. Check them straight away when I get back. Around town it feels ok most of the time, but even then on a sunny day it does feel worse, and I guess that's as the road temperature can be much much hotter.

Kreeeee · 9 Jun 2015 at 12:46

You need to check the pressures when cold for consistency, not when warm.

robin7 · 9 Jun 2015 at 12:50

Kreeeee said:
You need to check the pressures when cold for consistency, not when warm.

Well cold I know what they are since I check regularly, 36 front, 42 rear as recommended in the manual.

I meant to see if they do go up/by how much driving around in my normal use since road temps are so hot I'd imagine a normal hour or two on the road would heat them up pretty fast?

Or am I confused?

Kreeeee · 9 Jun 2015 at 12:53

5 minutes will get them up to operating temperature. I would lower by 1-2 PSI (cold) and have a nice ride to see if you prefer it. If not, wait until cold and try again.

I wouldn't go below 30 though unless you have chicanes like I have and you ride them hard (which I don't).

ttaskmaster · 9 Jun 2015 at 12:54

robin7 said:
Well cold I know what they are since I check regularly, 36 front, 42 rear as recommended in the manual.

Ignore the manual.

Go see what the tyre manufacturer says, as they built those specific tyres to work on your specific bike at pretty specific temperatures.
Usually the values are about the same, but I have had some where they're quite different... and on some bikes even 2psi difference can make ALL the difference!

robin7 · 9 Jun 2015 at 13:06

ttaskmaster said:
Ignore the manual.

Go see what the tyre manufacturer says, as they built those specific tyres to work on your specific bike at pretty specific temperatures.
Usually the values are about the same, but I have had some where they're quite different... and on some bikes even 2psi difference can make ALL the difference!

Bridgestone S20 Evo's but not sure on the size, will check and google.

Just saw this: http://www.600rr.net/vb/showthread.php?t=286664

Turns out 36/42 is what they say also.