"Bargain basement widebody" rim fitment help

[empiiw]

I'm having a local shop install some reasonable looking custom built fender flares to my stage 3 b5s4 track car. Can't afford legit widebody. Hoping it won't look like a pig. Will post photos once complete.

My goal is to run 275mm r-comps. After a bit of research it looks like I need the following wheel and tire setup.

18x9.5
Offset 15-20ish
Tire. 18/275 35

Want to put stoptech 355mm 6 piston under there.

However. Damned if I can find wheels. Also I'd love someone to tell me if this is the right setup for the car. Rs4 can run 275s right? I thought it would be easy to find rs4 wheels for this car (I believe the rs4 wheel would be the right offset to fit after the arch mods) but I'm really struggling

[SomeDayAS4]

use some spacers. plenty of 9.5 wheels out there

[mauromj]

rims.

[empiiw]

rims.

lol. Thanks - changed title and post to reflect "wheels" which is indeed correct. Not sure why I referred to them as "rims"

[empiiw]

use some spacers. plenty of 9.5 wheels out there

How big a spacer can one safely run on a track car? If i purchased ET 55 wheels, I'd need 40mm spacers. Is that even safe?

[audi-hammer]

I see you are two towns over, might be doing the same thing. I would try to run no spacers, 20mm is bigger than I would want to run on the street. What made you come to the decision of those offsets?

[audi-hammer]

Find joevwvortex's thread as he did the exact thing you are talking about, he used fender flares in the back and rs4 front fenders and he lists his wheel/tire specs

[chris@fifteen52]

We have our Tarmacs in 5x112 18x9.5 et40 or we have blank, raw wheels in 18x9.5 and we can do custom specs. Or we do have 5x114.3 18x9.5 et25 that we can redrill and insert to 5x112. Also have 5x114.3 in 18x9.5 that we can do any offset from 0 to 45 that we can redrill and insert.

[james 408]

you're dead-on on specs. good luck finding a wheel in the US. There are options but not a ton. I might go closer to ET15 for 275 track tires, depending on which one you chose, they vary in tread and section width by over an inch. I wouldn't go much wider.

If you just find the right offset, forget bolt pattern, and have a quality redrill you'll be good. Then a hub centering ring. Plenty of jap evo/wrx wheels will work. I'd avoid spacers, don't like em.
You need to get a brake fitment diagram for your brake kit. You send the pdf to the wheel supplier and have em put it on a piece of cardboard if necessary. You just cut it out, stick it inside the hub of the wheel, and bam, you know spoke clearance.

Keep in mind tire cost, fuel economy etc if you're doing this on a daily.

[acoleman]

I had the same issue. I have the JDM flare setup and just ordered some Rotiform ind-t in 19x10 et25. I'm hoping to run 265/30/19. I can update in a couple weeks when they are installed about fitment. But others are right, pickings are slim for this size wheel. I ran 25mm spacers on my old setup and got tired of them. Didn't have any issues though it was only on the street.

[empiiw]

We have our Tarmacs in 5x112 18x9.5 et40 or we have blank, raw wheels in 18x9.5 and we can do custom specs. Or we do have 5x114.3 18x9.5 et25 that we can redrill and insert to 5x112. Also have 5x114.3 in 18x9.5 that we can do any offset from 0 to 45 that we can redrill and insert.

Chris this is awesome. What is the weight of the Tarmac? Will they hold up to track duty? Will they clear a 355mm stoptech st-60?
I guess I would need 18x9.5 *5x112*
Offset 15. Will I need hubcentric rings? What is the cost shipped to Syracuse ny? Colors?

[chris@fifteen52]

PM sent

[empiiw]

The more I think about it it might make sense to by ET 25 and then have the option to run spacers if need be. Always worth having some options. Any thoughts on that? I know that Et15 on 275's would be the same as ET35 on my 235's I have now (and they work perfectly) but if there's more room to move the wheel back I would be wise to take advantage of that.

One other question. If I were to add adjustable control arms to add more camber, does that "push" the bottom of the wheel further out, or pull" the top of the wheel in more? and how much does that impact the ability for the tire to turn and if so would I be wise to adjust my ET accordingly?

[james 408]

bro, you can't even fit the largest 265 track tires on ET20. inside upright in rear rubs. Do what you want but you have been warned.

Camber is adjustable in many ways. if you're adjusting via the upper control arms, increasing camber reduced clearance up top. If you use the lower control arms, that would move the wheel out at the bottom. Both of these options would require aftermarket parts. (lower rear slightly adjustable stock)

[geeky]

Why are you pursuing a ST60 6pot setup when a 4pot is more than you need for a B5 S4? You're just adding more weight with minimal clamping force gains. I work for a BBK company

[empiiw]

bro, you can't even fit the largest 265 track tires on ET20. inside upright in rear rubs. Do what you want but you have been warned.

Camber is adjustable in many ways. if you're adjusting via the upper control arms, increasing camber reduced clearance up top. If you use the lower control arms, that would move the wheel out at the bottom. Both of these options would require aftermarket parts. (lower rear slightly adjustable stock)

Wait what? Isn't 265 et20 identical to 235 et35 and I run those now (bf Goodrich gforce) which have are wide tires (wider than Hoosiers). Help me out. What am I doing wrong.

[empiiw]

Why are you pursuing a ST60 6pot setup when a 4pot is more than you need for a B5 S4? You're just adding more weight with minimal clamping force gains. I work for a BBK company

I'm looking for the coolest (heat) setup possible. I was working under the assumption that a slightly larger pad surface would dissipate heat better than 4 pot. Nothing to do with clamping force. Weight wise I'm not too worried but if the heat profile is the same I would go 4 pot. I'm no expert that's why I'm here looking for advice. Help is appreciated.

[empiiw]

Geeky and james. Just criticism or do you have further input or any feedback?

[cinesnow]

why go through all that trouble and get 275's? i ran 285's and am currently on 295's which have the correct outer diameter, if you are keeping your abs/esp. 275's are 2.2% smaller in their rollout if i recollect and it will be overgeared. look up "going outlaw" for my notes.

[geeky]

Heat dissipation will occur with a large frame and airgap of the rotor ring. Increasing the surface area of the caliper with an ST60 will assist with heat dissipation from the pads, but the true hea issue with brakes is the rotor. If you utilize an ST40 kit with the same rotor as an ST60 in regards to cheek thickness and rotor veins being curved, the next step is to look at the airgap. The larger the airgap, the better the heat dissipation efficiency of the rotor and better temperatures.

You can get away with doing a ST40 with a higher mu content pad and acheive the same if not more consisten brake feel than an ST60.