PDA

View Full Version : Tyre pressures



130wide
5th November 2003, 18:50
Just interested in what pressures you run in your tyres.

The Turbo, 110-80-18 front 130-80-18 rear I run 30psi in both.
Anything higher or lower makes the bike feels sluggish.
These are the same pressure I have used on R6's and R1's for best performance.

wkid_one
5th November 2003, 19:17
Shit that is low...

I run 36 in the front and 38 in the rear.

Running 30psi would shit my tyres out too quickly and I wouldn't trust that low a pressure in my front - too much tyre flex.

MikeL
5th November 2003, 20:51
Is there really anything to be gained by departing from the manufacturer's specifications? I have found in both my bikes that I can run 1 or 2 psi over the recommended pressure (33 for one and 36 for the other) without noticeable effect but if it drops more than about 1.5 or 2 psi below it starts to become noticeable.

wkid_one
5th November 2003, 21:05
Most sports bikes are set at 36 front and 42 rear by Manu

It has to do with a lot of variables - tyre compound, road condition, road temp, ambient temp, speed, type of riding etc.

Many people must ride on OEM specs with no dramas.  I run OEM on the front tyre, slightly less on the rear - even less again on the track.

The actual trick is to understand what your HOT pressure should be as this gives you the best indication of the optimal ride condition.

When you measure cold you run some risks - is the tyre colder/hotter than normal (your cold pressure in winter will measure differently from summer) - this then flows on to what the hot pressures will be.  have you ever gone out to the bike on an extremely abnormally cold morning and noticed your tyres have 'lost' pressure??  They haven't - it is just pressure fluctuating with heat changes.

SBK teams know what the HOT pressures need to be - not the cold.  Given it is when the tyre is hot that it gives the best grip - you are better to know your hot pressures. 

In essence, your cold pressure are largely guesstimation - as given all the variables - you will never know how hot the tyre will get and what the ultimate pressure will be.

If you run the same pressures winter and summer - you will find your hot pressure will vary significantly - as road temp and air temp all contribute to getting your tyre hotter.

I had a bunch of information on this from a website - I will try and find it again.

I would think running at 30psi on the road - you would be overheating your tyres something wicked due to the increased friction.

130wide
6th November 2003, 05:41
I'm thinking the same wkid_one, if you start of at 30psi, after riding a while the psi in your tyres will increase due to the heat build up and hopefully to the optimum psi of 34psi.

Firefight
6th November 2003, 05:57
Originally posted by 130wide
I'm thinking the same wkid_one, if you start of at 30psi, after riding a while the psi in your tyres will increase due to the heat build up and hopefully to the optimum psi of 34psi.


Having seen you ride, (albiet as you disapear into the distance,) I should think it would not take you long to get your tyres up to temp Ric !:eek:

I hope when you come up to woodhill I have a better chance of
keeping up with you:cool:


firefight:p

wkid_one
6th November 2003, 06:11
Yeah - which is great 130 - but tyres that start at 36psi are more lkely to end up at 40psi - which is more than optimum - hence the problem of cold tyre pressures.

34psi is still a light colde pressure, let alone your HOT tyre pressure.  Take you bike around the track - whip in to the pits and see what your hot pressures are in comparison to your cold - you will be surprised

750Y
6th November 2003, 09:16
I generally like to keep my rear a couple psi higher than the front.

Motu
6th November 2003, 11:49
So we still think in psi eh? What about you young guys - kpa the way to go?

Riding older bikes and dirtbikes,my thinking on tyre pressures is biased.

25psi rear and 20psi front on my road bikes....3 or 4 psi on the trials bikes,used to run 8 psi flat tracking,off road is a compromise between traction and damage...20 to 25 rear,15 to 20psi front.

Off road low pressures mean traction - when flat tracking 1/2 psi was a big difference,we would increase the pressure to take the bite out of a sticky track.

If I put the recomended pressures in my Honda (32psi) it starts to slide,so down they go again - squirming around on soft tyres is no probs for me....don't go fast enough for them to overheat.

Marmoot
6th November 2003, 13:23
Smaller tyres only need lower presure as well. Probably because normally they are fitted onto smaller bike (lighter).

I remember when I had my CB200 the manual said 28psi rear (120 wide) and 25 front (90 wide).

You're probably already spot-on there with 30. Try searching in the internet, they should have some info. At one time in band camp there is this thing they call Google.....

Redstar
7th November 2003, 20:48
:)
well expert not but it I 39 rear 36 front and that more than the manufactures suggest but then they recommend a safe pressure
for BT120 rear and bt110 front at 36 32 but then I would square off the tyres real quick? so your pressures sounds low to me?
dont forget that hot pressure will be higher.

why not up it a bit