Yamaha TRX850 Enthusiasts Forum

Dunlop recommends 2,5 bar front and 2,9 back...
...But what would you set for a trackday??

I would have thought a lot lower, Its a long while since I've been on a track, but something like 1.9 bar on the front and 2.25 on the rear? I'm sure Honk, Phuk and the rest will give you better figures, but again it is all down to personal preference. Dont forget that the tyre doesn't get a chance to cool down on the track.

Dave E

I've found 30 psi front and rear to work really well with my Michelin slicks. Don't know how many bar that is.

http://www.dragsource.com/index.php?nav ... lctoview=8

Bar to Psi converter, or the other way round if you want.

Dave E

Kevtrx849 wrote:I've found 30 psi front and rear to work really well with my Michelin slicks. Don't know how many bar that is.

Just above 2 bar then...What size slicks?

leave them standard to start with (ad certainly don't take any advice on here as there are too many variables!)

people worry too much about tyre pressures, suspension settings etc when they should be worrying about learning the track, braking points, hitting the apex etc.

the principle behind lowering tyre pressures is that you heat the tyres up more on the track and that has the effect of expanding the air thereby increasing psi. TBH, you will not notice a few psi at first

FWIW I run 30 rear and 28 front on super corsa pros on hot days - a bit less when cold

Killerwhale wrote:

Kevtrx849 wrote:I've found 30 psi front and rear to work really well with my Michelin slicks. Don't know how many bar that is.

Just above 2 bar then...What size slicks?

160/60 and 120/70 Pilots

Pilot power 30F 28R

slow codger wrote:http://www.dragsource.com/index.php?nav ... lctoview=8

Or
multiply by 14.7 to convert bar to psi
divide by 14.7 to convert psi to bar

I discovered the other day that on the Sainsbury's tyre pressure machines there's a button so you can change to bar ... dunno if it's the same on other machines here (am I being blonde - did you guys already know that? )



amended to 14.7 after QT posted!

14.7psi = 1bar = 1atmosphere (what you are standing in right now)

Personally 32psi front / 33psi rear

a good medium for just about any tyre is the "5psi" rule. Measure your tyres cold, before you go out, soon as you finish, measure again as soon as humanly possible. They should be ~65degC and up, slicks hit about 85degC (not that you really need to measure that). they should be 5psi different. If its LESS than 5psi, add air, if its MORE than 5psi, let some out.

Its not perfect, but it does give you a fairly good base to work with.

Quan-Time wrote:14.7psi = 1bar = 1atmosphere (what you are standing in right now)

Personally 32psi front / 33psi rear

a good medium for just about any tyre is the "5psi" rule. Measure your tyres cold, before you go out, soon as you finish, measure again as soon as humanly possible. They should be ~65degC and up, slicks hit about 85degC (not that you really need to measure that). they should be 5psi different. If its LESS than 5psi, add air, if its MORE than 5psi, let some out.

Its not perfect, but it does give you a fairly good base to work with.

You are having a laugh aren't you?

Slicks run at 100 degrees plus and many road legal race tyres (for example Super Corsa Pros in a track compound) will reach 80-90 degrees if not more. Race wets in the pouring rain will go over 65 degrees.

I have measured my tyres hot and they go well over 40psi from a 30psi cold start.

Keep them standard is still my advice until you can feel the difference

what is standard tyre presures I run 33f 35r

depends. you should use the pressures recommended by the tyre manufacturer.

pressures for oe Mac 90s are 32f 36r.

For BT014 for example 36f 42r.

wot he said ^^^^

(and when I talk of standard i mean what you run on the road and feel comfortable with)

phuk72 wrote: You are having a laugh aren't you?

Slicks run at 100 degrees plus and many road legal race tyres (for example Super Corsa Pros in a track compound) will reach 80-90 degrees if not more. Race wets in the pouring rain will go over 65 degrees.

I have measured my tyres hot and they go well over 40psi from a 30psi cold start.

Keep them standard is still my advice until you can feel the difference

If you are racing hard, yes, corse they will. Tyre warmers on slicks go to about 85 - 88 alone before you even get out. If you are on the edge and REALLY pushing hard naturally they get way hotter.
If you are asking the question, you probably aint the biggest racer in the pack. Thus, its a good place to start.

Normal riding on the road can provide upwards of 5psi on a nice warm day. So it will something you are familiar with. You can build from there.
Sorry if it sounded like a joke or a bit retarded, But for someone just starting to track ride, its a reasonable place to start.