Federal 595 Rs-R Pressures/grip Etc

[No Crust Racing]

Had my first run at Winton on these on Friday and they compare reasonably well to what they were replacing (very old/worn/heat cycled RE55s)

The old RE55s still had more outright grip and handled the heat build up over a session better but for $640 for 4 brand new tyres the RS-R's do pretty well.

Something I'm interested in is what other RS-R's users are doing with pressures.

I found that after a decent 5-7 lap stint the RS-Rs started to get greasy and I was getting a bit of rubber build up on the edge of the tread block.

I spoke with Federal before running these tyres and they suggested a cold start pressure of 36psi, a quick check of pressures when returning to the pits showed around 40-41psi in all four corners.

I didn't get a chance to experiment with different pressures as some debris on the track damaged a valve and ended my day early.

What have others found in regards to pressures they are running and how they find it.

Quick run down on the car.

S13, not much power, only 160+rwkw

-2.5 camber front, -1.5 rear

Toe is definitely out at the front at present (fixing that this week before the next track day)

-1mm toe in the rear.

damper was set on full soft as a few clocks harder up had the car getting skatey and wanting to understeer.

8/6 springs, standard bars.

Ambient temp on the day was only 13-15deg

Edited September 12, 2011 by ActionDan

[scooby36]

hey mate, recommended pressures from federal are pretty close

in my silvia, with 215 and 235 rsr's i used 34 front and 31 rear, which grew to 45 and 37 respectively to go fastest around lakeside

[No Crust Racing]

That's a lot of growth in pressures, you are clearly going faster than me

Federal called me back (awesome customer service) and we discussed my setup in more detail. He suggested dropping the pressures a touch 2-psi front to back respectively so that puts it on about where yours are.

I'll try this at the next track day the weekend after this one.

How many hot laps are you getting? what camber/toe/spring rates?

Cheers for the feedback.

[scooby36]

no wuckas mate

over about 5 hot laps, car weighs 1200~kg, camber of about -3 front and -1 rear. toe is rougly 0 all round, springrates 7/5kg

rsr's didnt give fantastic feel/feedback compared to the cheaper ku36's.. felt a bit funny at the limit, not much warning that you were about to go beyond it. but about 1sec quicker so cant complain too much.

[No Crust Racing]

Cheers

See how I go next track day, bit of a change going from R-comps so will take some getting used to.

[ordinary]

That's much MUCH higher than I run on an R33 GTR... I run 28-29psi cold and 35-37psi hot... The tyes start to go off after about 3 - 4 laps at Phillip Island and so I just figured they were too hot...

I'll trying running them higher but I reckon they will go off faster - I'll report back soon

[No Crust Racing]

I'm dropping mine for this Saturday, will be trying a cold start pressures a few PSI lower than before. Will be taking my good gauge and my compressor so I can adjust as necessary.

I've had an alignment done as well so this might help a bit also.

[Marlin]

I've never understood settings using cold pressures..... every car treats them and heats them differently.

Hot is where it's at

[No Crust Racing]

It's just a starting point Benny. You don't just rock up at the track with no idea of what pressures are in the tyres to start with. For those of us without proper tyre gear, like a pyrometer, we need a reference point of some sort.

I know that my car, given a certain ambient temp range, will increase tyre pressures around 4 psi from its cold start pressure, But that's just coming back into the pits after a session, and checking temps quickly. Which is affected by how much cooling down I did before coming in etc. In actual fact it could be 4-8psi on track which I'd never know without having some of those fancy pants wireless valve cap type sensors. Or coming straight in after a hot lap to a waiting mate with a pyrometer at pit entry to check temps.

So, we need to start somewhere and we're not exactly racing for pink slips here

[Marlin]

Yeah I understand that, BUT.....

Set them cold approx 5psi less than your hot temp.

Go out for your first session, heat them and do some laps but don't over-cook them.

Come back into the pits, bleed them back to your desired hot pressure. Then simply check pressures at the end of each session just to make mild adjustments as you see fit.

I don't use pyros mate, I'm not altering camber etc at the track

When I ask folks what pressures they're running, and they reply with "xx psi COLD", I slowly back away. lol

[No Crust Racing]

Yeah fair point, as I said though it's a starting point only.

TBH I don't really want to be making pressure adjustments after every 15min session anyway, I'm too lazy for that

[Marlin]

Really! lol. Ok

I would have thought that for someone concerned about the cost of rubber, and therefore, looking after them as best you could, checking pressures often would be a given.......

I know I absolutely try to get the most from tyre's life, coz they're farking expensive! I check my tyre pressures more than look at my temp or fuel gauge, because a set of rubber is dearer than a new engine

Edited September 22, 2011 by Marlin

[No Crust Racing]

Completely agree!

I didn't say I did not check pressures, I said I didn't want to do it every session because I'm lazy. I keep tabs on the temp and the weather and if the tyres go off sooner or later I check them again when I return. This is why I know how much my pressures come up and why I'd had chats with Federal about it.

At the moment, I'm trying to find the right pressure to keep them on for longer and give me max gripz

[Marlin]

Okays

[No Crust Racing]

Side bar: You do less work than I do...

[Marlin]

Don't be J .....

[No Crust Racing]

[Beer Baron]

considering how cheap TPMS kits are these days (around $250 will get you a set of 4 wireless sensors and a display unit) they are worth looking at for anyone half serious about cutting good times. there are also tireliefs. they are a pressure release valve. you set them on the bench for your desired hot pressure. fit them to your tyre valves (or drill a hole in the wheel rim and fit them there) and on track as your pressure grows when it hits the desired pressure the valve will let any excess pressure escape to keep them at your desired set pressure throughout the session. you can even just set your tyres straight away to your desired 'hot' pressure and the tireliefs will start bleeding pressure as the tyre heats. they are a cool idea.

[No Crust Racing]

That's awesome. If I ever have a car that goes beyond club level hacking I'll certainly consider that sort if thing.

The S13 is just a fun hack to tide me over until I've paid off enough on the house to warrant another GT-R.

[R34Targa]

I used these tyres yesterday on EC. They produced great grip for the first three sessions but the last two the rear slide a bit more.

Still I highly recommend them for road and track.