best road legal trackday tyres?
Discussion
Aplogies Fergus, i was looking fo the info on the slip angle, it was in a suspension set-up book i used when looking into car set-up.
The sizes i used and have been used with a few of my mates with the same tyre choice, were 8.5 rears and 7 front. Think they were both on an offset of 24+. If this sounds wrong then its a negative offset, but im sure its +. The wheels are on my mates car down south so cant check.
The sizes i used and have been used with a few of my mates with the same tyre choice, were 8.5 rears and 7 front. Think they were both on an offset of 24+. If this sounds wrong then its a negative offset, but im sure its +. The wheels are on my mates car down south so cant check.
Hi fergus - sorry don't read pistonheads much at the weekend.
Recommended rim sizes are 8" front and 9" rear but nearly all of us are using 7.5" front and 8.5" rear. This was purely because most already had 8.5" rears and they just added 1" to the outer rims for the front wheels (6.5" being the standard Caterham size on MB wheels).
I ordered wheels from Image using the standard Caterham backdepths (hub face to edge of inner rim). Rear wheels end up about ET20 and fronts about ET5 - pleae check this carefully as I am not 100% confident in my maths. Image (and I am sure most other suppliers) can work purely on the back depth measurement. Standard Caterham backdepth is 140mm rear and 113 mm front (110mm on the MB front wheels).
With those wheel sizes, the rears "just" fit under the arches and the fronts will need new wider wings. I have used carbon-bits 240mm wings but as these are not available at the moment you'll need to find another supplier. Lots of people have used the CSR style wings and modified the wing stays.
Edited to correct my maths.
Recommended rim sizes are 8" front and 9" rear but nearly all of us are using 7.5" front and 8.5" rear. This was purely because most already had 8.5" rears and they just added 1" to the outer rims for the front wheels (6.5" being the standard Caterham size on MB wheels).
I ordered wheels from Image using the standard Caterham backdepths (hub face to edge of inner rim). Rear wheels end up about ET20 and fronts about ET5 - pleae check this carefully as I am not 100% confident in my maths. Image (and I am sure most other suppliers) can work purely on the back depth measurement. Standard Caterham backdepth is 140mm rear and 113 mm front (110mm on the MB front wheels).
With those wheel sizes, the rears "just" fit under the arches and the fronts will need new wider wings. I have used carbon-bits 240mm wings but as these are not available at the moment you'll need to find another supplier. Lots of people have used the CSR style wings and modified the wing stays.
Edited to correct my maths.
Edited by Shaun_E on Tuesday 8th December 09:27
On the subject of tyres there really is note a lot of difference between CR 500's or AO 48 R's. On a summers day R 400's ( rover k series ) on 48's will do 1.15.5's as will a C400 will on CR 500's at Snetterton. The 48 gives a little better grip in the dry and the 500 is better in wet conditions. At Snetterton in a CSCC race a CSR did a 1.14 odd on Kumo's
On the subject of tin tonne covers yes a bone of connection. Scrutineers only follow the blue book.
On the subject of tin tonne covers yes a bone of connection. Scrutineers only follow the blue book.
sam919 said:
The Hoggarth car was another R400, think he was on yoko's. Dont know what Sharman was in. Marshall and Morris still using the Kumho, the rest on slicks untill position 14.
Sharman would have been in a Megagrad (135bhp, wide track, no screen, no headlamps) running on Ao48'sThe 48's are a good tyre for lap times and endurance, but they wont help your driving. You can be an utter arse with them and still be quick and they'll never go off significantly, so there's not a lot to be gained by being smooth.
There are lots of tyres better than the CR500's for grip, but they're nice and progressive and as they overheat easily they punish overdriving in higher powered cars. I personally think they're a good tyre for the Caterham.
The Michelins are also an excellent slick tyre, I'd suggest getting a new set of those if you can afford them. You will be amazed at how much better they are when brand new.
Seriously interested in the new CR500+ tyres though, the 500's are a bit underspecced for a C400
The Wookie said:
The Michelins are also an excellent slick tyre, I'd suggest getting a new set of those if you can afford them. You will be amazed at how much better they are when brand new.
Seriously interested in the new CR500+ tyres though, the 500's are a bit underspecced for a C400
I think the Michelins are pretty awesome when used! Might have to treat myself to some new ones one day!Seriously interested in the new CR500+ tyres though, the 500's are a bit underspecced for a C400
JakeR said:
I think the Michelins are pretty awesome when used! Might have to treat myself to some new ones one day!
Old vs new is worth up to 1.5 seconds a lap in a Porker Cup Car. Bearing in mind old to us is only an hour or so's running, although the Porsche is a much heavier car. A set of proper 'we've run out of testing budget dustbin out the back of the workshop' specials can put another second on top of that
The Wookie said:
JakeR said:
I think the Michelins are pretty awesome when used! Might have to treat myself to some new ones one day!
Old vs new is worth up to 1.5 seconds a lap in a Porker Cup Car. Bearing in mind old to us is only an hour or so's running, although the Porsche is a much heavier car. A set of proper 'we've run out of testing budget dustbin out the back of the workshop' specials can put another second on top of that
.This is on Michelins that have maybe 3-4mm of tread left shown by the wear indicator...
JakeR said:
This is on Michelins that have maybe 3-4mm of tread left shown by the wear indicator...
I'd be more concerned with the number of heat cycles than the 'wear' indicators. I used to race a clio cup car, and the tyres went off after about 2 heat cycles, to the extent that Mr. Wookie has indicated..... beware of greasy slicks, then can have you into the armco!JakeR said:
My experience is very much limited to trackdays, so I have no real way of knowing any time differences. However, the car seems way better under braking than I have experienced on cr500s or AO48Rs, real 'OH MY GOD I'M NEVER GONNA STOP IN TIME!!!' stuff .
This is on Michelins that have maybe 3-4mm of tread left shown by the wear indicator...
If I had to describe the difference between new and old in a single word it would be 'tight'. They feel a lot more precise, there's no slop in the responses, they just bite instantaneously..This is on Michelins that have maybe 3-4mm of tread left shown by the wear indicator...
As Fergus said though, heat cycles and subsequently age are more important than wear.
A word of warning though, if you bought your existing tyres second hand and end up getting new slicks then be very very careful for the first few laps, they're like driving on ice. The first time I went out on brand new slicks it's was dumb luck I didn't end up wedged, Austin Powers style, between the two walls on the pit exit at Brands. Literally 50 yards after they'd put them on the car.
Edited by The Wookie on Tuesday 8th December 15:20
fergus said:
people seem to think that a slick 'must' offer grip straight out of the pitlane... 
That extremely expensive back bumper must have come within a fag paper of both pit walls, lock stop to lock stop, before I flukily gathered it back up and carried on with only minor damage to my underpants.
You live and learn
Im trying to sort out slicks for next season, here's one to ponder over.......silverstone's!
Ran them last year and they were ok but didnt really get to grips with them, had a couple that were used with a couple that were brand new, so difficult to get an accurate feeling for them. Having said that i wasnt preppared to lash out a load of dough to test them. Ultimatly they were good and excellent in the wet, as per Mallory a fwe weeks ago on a track day.
Based on the times i have used them im going to give them a good shot next year. They also do a semi slick road legal tyre, but think theyre limited in sizings.
Im sure all thes tyres mentioned are good, drivings styles/ championships/ costs/ they all play a factor, its just whats suits the person using them and there discipline
Ran them last year and they were ok but didnt really get to grips with them, had a couple that were used with a couple that were brand new, so difficult to get an accurate feeling for them. Having said that i wasnt preppared to lash out a load of dough to test them. Ultimatly they were good and excellent in the wet, as per Mallory a fwe weeks ago on a track day.
Based on the times i have used them im going to give them a good shot next year. They also do a semi slick road legal tyre, but think theyre limited in sizings.
Im sure all thes tyres mentioned are good, drivings styles/ championships/ costs/ they all play a factor, its just whats suits the person using them and there discipline
There are shims available for De Dion cars that allow a camber (& toe) change with the existing ears to fine tune to different tyres & handling requirements.
http://www.dpr-motorsport.com/accessories/caterham...
http://www.dpr-motorsport.com/accessories/caterham...
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