Slicks, What Air Pressure should I run?

**gav** · 30th July 2008, 19:14

Originally Posted by Pumba

Hey, as the title says.

Managed to pick up a set for my FXR project, fitted them, and just wanting to know whats a good starting pressure to run them at, at Mt Wellington.

I was thinking about 20-25 PSI, am I wright or wrong.

What size tyres did you get? Have you got two fronts or a 125GP rear?

**Buckets4Me** · 30th July 2008, 21:06

back to this question
as I understand it you need to worry about the tire heating up
so on a long fast track you run higher pressures 25-30 psi to stop
the tires overheating

and on a slow track (best speed i have seen is 90ish k/h)
you run lower pressures to heat the tires up
yes they do deform thats what heats them up

they need to be warm to the touch

I know at the last meating one guy tried 14 psi in his tires and they still wernt heating up (yes we did have hail and lots of it)

anyway good luck and ask soem of the good guy's
there are a few 600 racers out there they now a lot they are the fast ones
one of them was running wets in the dry last time trying to get them to heat up (he definatley wasent cooking them)

**Pumba** · 30th July 2008, 21:12

Originally Posted by SHELRACING

Assuming you have removed the Tubes.

Tubes are still in. I was to cheap to take them to anyone and just did it with a few tire iorns at home

Originally Posted by F5 Dave

But I'd also add a pound or two if you are, um how can I put this?

or your bike is a porker.

Thanks for the info. We will say it the bike is on heavier side and it has nothing to do with my, eerrmm, solid build

and put a couple of PSI in to compensate

Originally Posted by gav

What size tyres did you get? Have you got two fronts or a 125GP rear?

Front 95/70/17 and rear 115/70/17, Dunlops, couple of ex 125GP tires

**gav** · 31st July 2008, 07:06

So you've mounted the rear on a standard FXR rim, 2.15 x 17? That tyre would work best on a 3.5" rim.

**Sully60** · 31st July 2008, 08:41

Originally Posted by gav

So you've mounted the rear on a standard FXR rim, 2.15 x 17? That tyre would work best on a 3.5" rim.

Yeah, you'd be better off putting a front tyre(95) on that in reverse direction. The 115 is too wide for the rim and will give a squidgy feeling and you're likely to run of the tread much earlier and in a less controllable fashion.

**dangerous** · 5th August 2008, 06:31

on all 3 buckets I run 27psi F&R never had any issues

**enigma51** · 5th August 2008, 07:20

Originally Posted by dangerous

on all 3 buckets I run 27psi F&R never had any issues

Thats cause your dangerous!

**Sully60** · 5th August 2008, 08:19

Originally Posted by dangerous

on all 3 buckets I run 27psi F&R never had any issues

You're a walking issue!

So what was the go on the BoB warm up lap, was that something other than a problem?

**k14** · 5th August 2008, 10:19

Originally Posted by Sully60

You're a walking issue!

So what was the go on the BoB warm up lap, was that something other than a problem?

That was the thing sitting on the seat, nothing to do with the tyres.

**dangerous** · 5th August 2008, 17:43

haha... farking wankers

Ok so what presures would you guys reconmend on F4 and F5 bikes remembering 70% of tyres are on incorect sized rims and or to wide anyway?
(repost if already done so on previous pages)

**Buckets4Me** · 5th August 2008, 19:46

i run slicks and wets on 2.5 and 3.5 laced rims

about 16-20 psi

short slow track
bit more at taupo 22-24 ish maby higher maby not will see

**Pumba** · 5th August 2008, 20:01

Originally Posted by gav

So you've mounted the rear on a standard FXR rim, 2.15 x 17? That tyre would work best on a 3.5" rim.

Originally Posted by Sully60

Yeah, you'd be better off putting a front tyre(95) on that in reverse direction. The 115 is too wide for the rim and will give a squidgy feeling and you're likely to run of the tread much earlier and in a less controllable fashion.

Man the things nobody bothers telling you untill after youve done it

It will do for now, you live and learn.

**dangerous** · 5th August 2008, 21:00

Originally Posted by Buckets4Me

about 16-20 psi

bloody hell, that wont do the side walls any favours will it?

**speedpro** · 5th August 2008, 22:19

I think with the sizes you have, rims and tyres, you are just going to have to suck it and see. At Mt Wgtn keep dropping them down till it starts tank slapping over bumps or some other misbehaving starts happening. Keep an eye on what the tyres are looking like. If they start working at 20psi then there is no need to go lower. Your rear tyre is definitely too big. I've run tubed TT900GP front 90X17 rear 100X17 at 18psi & 19psi respectively on 2.15 rims. 17psi and it was even more evil than normal and more than 1psi higher the tyres never warmed up. 23-25psi is a good point to be starting.