Oulton Park Trackday Fri 2Nd Mar Trackaction - Wscc

[s2rrr]

Don't forget your kettle, tea, coffee, milk, biscuits, money for your bacon egg and sausage roll . Oh and your driving license, ignition key, crash hat, FIA key, money, gloves etc cold last weekend .

Enjoy

Bob :yes:

[stephenh]

If you want to look your best, dont forget your bucket sponge and leathercloth!

[Tonsko]

Weather looking good! Dry all week, although cloudy friday between Chester & Northwich.

[stephenh]

Washed my car yesterday. :cool: Oh and adjusted the tyre pressures. ;)

[Tonsko]

What pressure?

[stephenh]

That would be telling!! ;)

No, to be serious, I have 2 sets of wheels and tyres, one is my sprint set, with very soft rubber on.

The trackday/road use tyres are Toyo R1R, so medium/hard rubber by competition standards. They are on 15" wheels, 205/50 x 15" tyres. For a trackday I'd be starting off with them at about 17 psi cold at this time of year, and maybe check the pressures after a few fairly quick laps. If they went over 20 psi hot, then personally, I'd let a bit of air out to bring them down to that figure. Just MHO of course. At this time of year, with a cold track, I'd be surprised if they did go over 20 psi. They might if you use a much smaller tyre size though. On the road, I tend to blow them up to about 19 psi cold, because at road speeds they wont get so hot and therefore the pressure wont rise from the cold setting so much. All this changes in warm summer weather of course, but only by the odd lb. or two.

I tend to run the sprint tyres at slightly lower pressures, to try and get them to heat up quicker, as they are only on track for short periods, given the nature of sprinting. Oh, and they're on 13" wheels, for lower ground clearance!

Some run lower pressures, but a while ago I was down to 14.5 psi cold on the sprint tyres, and then (because the rear felt a bit "loose") I increased the pressures by 1.5 psi, and it transformed the feel. A friend who knows much more than I do about vehicle suspension said it was because at such a low pressure, and quite stiff springs and dampers, the tyres were starting to behave as if they were the springs.

[Andrew]

SET UP ADVICE FOR THE TOYO PROXES R888

What I would like to do is to offer some advice on tyre temperatures and pressures and how to achieve the best from our tyres when taking part in either trackdays or racing.

The R888 has a semi race construction (very stiff) and a race tread compound. The optimum tread temperature range is between 85C and 95C measured using a probe type pyrometer, and ideally a maximum difference across the tread of 9C. The maximum hot pressure we recommend is 40psi. Camber angles up to 5 degrees are permissible but the final setting will depend on tread temperatures. It is advisable to have as much positive castor as practical as castor induces a beneficial camber change during cornering. I recommend that the tyres be put through a heat cycle before hard use, this will scrub them in and remove any mold release agent.

The pressures you use will initially depend on the weight of the car, too little pressure on a heavy car can lead to over deflection of the tyre and subsequent failure.

Below are some basic settings:

VEHICLE WEIGHT COLD PRESSURE HOT PRESSURE

Very Light < 800kg 17 - 22 psi 22 - 29 psi

Light 800kg - 1000kg 20 - 26 psi 24 - 32 psi

Heavy 1000kg - 1400kg 23 - 27 psi 28 - 40 psi

Very Heavy > 1400kg 27 - 35 psi 37 - 40 psi

As a tyre gets hotter the pressure increases, this is due to the moisture in the air. The cold pressure you set to achieve a desired hot pressure will depend on the conditions on the day i.e. ambient and track temperature, wet or dry. If the day/track is cold you will need to start with a higher cold pressure as the tyre will not get as hot therefore the pressure increase will not be so great.

Hot pressures must be balanced side to side. Once the tyres have cooled you will find that you will have a difference in pressure side to side, if you have been racing on a right hand track you will find the offside pressures will usually be higher than the nearside.

Changing hot inflation pressures by small amounts can be used to fine tune handling.

Reduce Oversteer Reduce rear pressures or increase front pressures

Increase Oversteer Increase rear pressures or reduce front pressures

Reduce Understeer Reduce front pressures or increase rear pressures

Increase Understeer Increase front pressures or reduce rear pressures

Achieving the required tread temperatures will depend again on the conditions on the day i.e. ambient and track temperature, wet or dry.

You often here competitors saying “My tyres started to go of towards the end of the race”, this is usually due to the tread getting to hot.

The tread temperatures are constantly changing through out a race, hotter when cornering and cooler when on the straights and cooling even more when you are slowing to come into the pits. Therefore the temps you record in the pits will be lower than those during the race. So if you record temperatures within the range given above the probability is the temps will be too high during the race.

Increasing your tyre pressures will cause your tread temperatures to increase, more pressure stiffens the tyre’s casing which results in the tread having to do more work resulting in the tread getting hotter. Lowering your pressures will cause them to decrease.

Inevitably changing one thing will affect other things, the whole set up of your car is a compromise between anything that is adjustable.

Alan Meaker

Technical and Motorsport Manager Toyo Tyres (UK) Ltd

[cast iron]

Oulton is a fab circuit, not going to make it myself, but anyone thinking about it will miss out on a gem if they dont

[Tonsko]

Just hope my remote linkage bolts arrive in time!

[Tonsko]

Was listening to some old Blaster Bates recordings the other day, and was reminded how he came to name Knicker Brook.

[stephenh]

Andrew, I am familiar with the Toyo recommendations. I've used pressures between 14.5 and 18.0 cold, on track with the sprint tyres, but never dared to try higher, although Matt at Procomp wanted me to try as much as 24 or higher. I dont know any front runners in the Speed Series who run above 18 on a Westfield using list 1B tyres. Raising the pressure is likely to reduce the temperature gain in the carcass and the air within, although raise the temperature of the tread because flex is reduced in the carcass but (in theory at least) increased in the tread.

Not sure that I want to be the guinea pig in the SS on that. Also, the tyre I use is VERY soft rubber, Kumho V70A. I dont know just how much in ideal world I want the tread to heat up on those. When Barry and Adrian run theirs at 24 psi, I'll more than likely do the same. :laugh:

[Westie66]

I love the Blaster Bates story on Knicker Brook, very funny

[Andrew]

Andrew, I am familiar with the Toyo recommendations. I've used pressures between 14.5 and 18.0 cold, on track with the sprint tyres, but never dared to try higher, although Matt at Procomp wanted me to try as much as 24 or higher. I dont know any front runners in the Speed Series who run above 18 on a Westfield using list 1B tyres. Raising the pressure is likely to reduce the temperature gain in the carcass and the air within, although raise the temperature of the tread because flex is reduced in the carcass but (in theory at least) increased in the tread.

Not sure that I want to be the guinea pig in the SS on that. Also, the tyre I use is VERY soft rubber, Kumho V70A. I dont know just how much in ideal world I want the tread to heat up on those. When Barry and Adrian run theirs at 24 psi, I'll more than likely do the same. :laugh:

Stephen, you do realise those weren't my words.. It's signed by the Toyo race techie guy.

I personally for trackdays, aim for around 20psi hot. Works for me.

[Pantherman]

Is it possible to spectate/ mingle at a track day ?

If so whats the cost ?

I might be free on Friday

Dave

[Andrew]

Is it possible to spectate/ mingle at a track day ?

If so whats the cost ?

I might be free on Friday

Dave

As far as I know it's free entry.. but if you take a helmet, and a small amount of cash, I'm sure someone would give you a few passenger laps. I would, but I'm not entered.