thoughts about track rims and tyres

[3wheels3]

Is there a price difference between 18" or 19" Cups? Not that I'm a tight arse git or anything

[shane@mbtech]

that is the conclusion i am coming to

what rims, pro race 1.2 18x9 ?

Yes pro race 1.2 18 x 9

It does feel different on the 18s, but ive not been on track with the 19's so cannot pass fair comparison really

Is there a price difference between 18" or 19" Cups? Not that I'm a tight arse git or anything

Negligable tbh wheels,

[Hazy]

18" Pro Race 1.2 rims, 18 x 9. Dunlop Direza tyres.

Wheels are cheap and bullet proof, tyres last longer than R888's

Done

thinking about buying another set for our E46 John, how much a set??

Funnily enough I have decided to run with 19" cups only so Hazy is after my 18" with the dunlops on (they are a great tyre and road legal!)

never mind after them, I deffo want them, just been busy!!!! Gotta pick up my new daily $hitter from near you next weekend, so will probably get them then mate :thumbs:

[Thorney]

6 cars running on 250 wide slicks on the Pro Race 1.2's for a season and never had any issues and tyre wear was enough for John to pikey out all season barely on one set. 265 rear tyre shouldnt be an issue on a 9" rim either but does depend on which one. Dunlop Direza's are fine.

Wheels are about £600 for a set, think we have a few in stock. Rays are better bet of course, I used to run 9" front and 10" rear but at £2500 a set they aren't cheap although even lighter than the Pro Race.

[shimmy]

Is there a price difference between 18" or 19" Cups? Not that I'm a tight arse git or anything

I will check with the Cups but I've heard difference is negligible as the 18 tyre is actually more rubber than 19 due to profile.

You will get rims alot cheaper but resale I guess will be harder.

The main reason in my mind for 18 rims is the weight saving and handling but if I could get 19 inch Pro Race 1.2 I would probably go for them so my tyre stock is not all redundant'

[_Nathan_]

9" is the narrowest rim that a 265 cup can be used on, same with a 250 slick, both suggest 9-10.5 inch wheel. A 250/640/18 Dunlip slick is 10.1" wide, it is designed for a 9.5" wheel. I've had good discussions with the tyre and wheel people about the issue of the car falling over itself as the tyre tucks under and the consensus was to go to a wider wheel to stretch the sidewalls and reduce the wheel moving inside the tyre hence my suggestion of a 10" wheel. My car is heavier than the cup cars so horses for courses and not suggesting what you've found isn't right, just different to what I've seen on my car.

Nick bell ran 18x10 BBS and later OZ on his car to great effect, worth having a chat with him?

I've got some 18x10 team dynamic 1.3s waiting to go on, fingers crossed my offset calculations were right

[shimmy]

Nick bell ran 18x10 BBS and later OZ on his car to great effect, worth having a chat with him?

I've got some 18x10 team dynamic 1.3s waiting to go on, fingers crossed my offset calculations were right

ive done my own calcs and your offsets are well out mate :thumbs:


but then i realised you will be running big camber and also want to widen your track as much as possible

from a road car point of view my calcs show that if i want matching rims front and back and 265 tyres (18 or 19) then to maximise the space available inside the front wheel you need to increase the offset on the bigger rims to best size et32 to fit the front as efficiently as possible.

This means the same rims on the rears have a say 5mm bigger to make use of the space to the strutts.

this means that the tyres will be 14.2mm further out, that makes the perfect rim the 18x10 et 30 from the catalogue but i would prefer a 19x10 et32 and hope that the extra camber needed to tuck under the front arch is not too much (-3 hopefully)

obviously different fro you race car, different priorities :supz:

[_Nathan_]

Remember that the width of the tyre face doesn't change and it is the tyre that needs to clear the arch, not the face of the wheel. I'd have liked a lower offset but they couldn't make them any lower, we'll see

Found this useful: http://www.1010tires.com/WheelOffsetCalculator.asp

This car is running 18x10 ET11 all round:

[shimmy]

yep, understand, i have been working on rubber sizes as the michelin specs for Cups.

http://www.tirerack.com/tires/Spec.jsp?make=Michelin&model=Pilot+Sport+Cup

i am trying to tuck the new rubber as close to the strutt as the current one is, assuming that this is as close as you want to get. CSL fronts are et45 and with the 18x10 and 265 cup this means for the inside of the tyre to be in the same place you need an et32

this just leaves the question, what camber is needed to tuck the 265 under the arches if it is sticking out 14.2mm further?

[_Nathan_]

Well you know that an 18x9 ET27 (m3 rear) fits just fine and that sticks out 24mm more that an 8.5 et45 so I think it'd be fine, also remember that loads of people run 10-12mm spacers on the front, again with no issues.

[TANKSLAPPER]

I have done a little testing on the front wheel clearance

This was with 3 degrees camber

The standard CSL wheel as we know is 19 x 8.5 et 45 fits
BBS CH'S is 19 x 8.5 et 35 fits
BBS CH'S 19 x 8.5 et 35 with a 12mm spacers fits = to 19 x 8.5 et 23

The standard CSL rear wheel on the front 19 x 9.5 et 27 just touches the outer side edge of the arch.

The BBS CH'S rears 19 x 10 et 20 rubs a lot.

So my cal's, would be to go for 18 or 19 x 9.5 et32 for the front and the same for the rear with a 15mm spacers

The problem is I can not find a wheel manufacturer that make such a size wheel lol

[TANKSLAPPER]

Here's some photos of BBS CH'S rears 19 x 10 et 20 on the front they rub on the outside edge of the wheel arch, but they do clear the suspension strut.

If you take out the wheel arch liner then they may clear.

I not going first through the foxhole lol

[shimmy]

So my cal's, would be to go for 18 or 19 x 9.5 et32 for the front and the same for the rear with a 15mm spacers

i dont think 9.5 or 10.0 will make a difference as the tyre section will be much the same so the opiton could be 19 or18x10 et 32

Team Dynamics Pro-race 1.3 (liuke Nathans) make a 18x10 et 30 which is guess would be the one to go for

Only troubles are;

1. Nathan uses them :gayfight:

2. Mazda Miatos use them as well:gayfight:

ALSO i just rang Rimstock and the Pro Race 1.3s with 18 inch 265 Cups weigh over 1 KG more than rear CSL rims with Cups:banghead:

[TANKSLAPPER]

i dont think 9.5 or 10.0 will make a difference as the tyre section will be much the same so the opiton could be 19 or18x10 et 32

Team Dynamics Pro-race 1.3 (liuke Nathans) make a 18x10 et 30 which is guess would be the one to go for

s

I agree that 9.5 or 10 j will not make much difference as both the standard CSL wheel ie 19 x 9,5 et27 and the bbs 19 x 10 et 20 touch the arch liner in the same place.

The only problem I can see with team Dynamics 18 x 10j et 30 is they may just touch the suspension strut.

You can see from the above photos that the BBS 10j et20 wheel is very close to the suspension strut ie about 10mm

I suppose 18 x 10j et 25 would work in my case with KW club sports on.

[shimmy]

the standard front CSL tyre is 165.7mm from hub face to iside edge of tyre

the 18x10 et 30 TD Pro race with 265 Cups would be 163.9mm from hub face to inside edge of tyres

so these should not touch the strutts even with 10 inch rims




the standard CSL rears measure 160.9 mm so thye clear the strutts easily but foul the wheel arch more becasue more of the tyre is set out (hence the reason for an et30-32 being best)