Jllewan

I want to upgrade tires and rims from the old 16" phone dials. I really don't want to do and major changes (rolling fenders etc..) What are my options? I do want to track it so I need clearance for that. 17's or 18's???

thanks

bw993

I track my 951, and I have 275-35-18 R7's in the front on 18x10ET60 wheels and 295-30-18 R7's in the rear on 18x10ET60 wheels. My car is lowered and has coilovers F&R, with a stock body and unrolled fenders.

Jllewan

Thank you!
Could I get details on lowering car and coilovers F&R? I have a lift and would like to see what it would take cost/labor to do this.

PDX-944

I have a turbo S, which is lowered and before flared I ran 315 in rear and 295 up front. the 315s rubbed only on deep compression, and the fronts managed to catch the fender lip and do a little damage at full countersteer on the weight bearing side of the car.
note that turbo S have factory rolled fenders.
with the right setup a 295 could probably work in the front. a 315 definitely works in the rear at most. 275 front and 295 rear would be a good setup.
keep in mind that more tire means longer to heat up. so for a basic setup, 275 maybe a good limit.

ground control is the easiest arrangement to use f/r
I have sleeves in the front, and coilovers as helpers in the rear. ive also upgraded rear TB to 30mm.

bw993

My car has the Bilstein Cup Coilovers with camber plates and the rear torsion bar is deleted, so adjusting the height of my car is straightforward. If you lower your car and plan to track it, I recommend going to aftermarket front control arms with appropriate pins and replace the stock front rubber bushings with Racer Edge spherical bearing equivalents.

Cloud9...68

But first, get a PhD in mechanical engineering. I'm joking, of course, but lowering these cars sets off an avalanche of side-effects, so I would do a lot of research into the impact it has on the relationship between the center of gravity and the roll center, and the impact and potential side-effects of the measures that can be taken to counteract the primary effects. Seriously, it's pretty complicated stuff. There's a great article about the topic in the November 2016 Grassroots Motorsports. The article is about lowering a Mustang, but that car has the same McPherson strut type front suspension as our cars, so the same principles apply.

Jllewan

Thanks guys!

Bw993 - Do you still recommend the 'aftermarket front control arms with appropriate pins and replace the stock front rubber bushings with Racer Edge spherical bearing equivalents' if I also use it for my everyday car? My first priority is to get the tires/wheel to fit then add upgrades down the road. Thanks!

bw993

Lowering your car puts stress on the stock 951 control arm ball joints, and tracking your car will only increase this stress. I did swapped out my control arms to aftermarket A-arms with spherical bearings for the ball joints and longer pins to support the lowered geometry, so I would not have to worry about a control arm failure on the track. This modification does not impact the street drive-ability of the 951, unlike everything else

Jllewan

Ok. Back to my original question...in order to fit what you recommended (275-35-18 R7's in the front on 18x10ET60 wheels and 295-30-18 R7's in the rear on 18x10ET60 wheels) I would not need to do anything at the moment unless I wanted to lower later down the road?

PDX-944

no you shouldn't have to do much. they MAY rub on the inside a little at full lock with ten inch rims. I had to make a sheet metal piece to cover my brake and fuel lines on the pass side. but its minor rubbing. with stretched tires at 275 you will be close, you can try a small spacer if it does rub.

PDX-944

which did you use?

Jllewan

I'm not having luck finding this combo with the same tire? 275-35-18 & 295-30-18 for Performance tires (not track) Any suggestions?

PDX-944

you should be able to find Toyo R888 in those sizes I would think. they are still R compounds, but quite streetable. Anything sticky in those sizes will be squirrely in ruts on the freeway FYI. im talking white knuckling... we have a few areas in Portland on I5 that pull like crazy

bw993

I am running a pair of SFR A-arms, with Racer Edge caster blocks. For a selection street summer performance tires, you may need to go with 265/35-18 (front) and 295/30-18 (rears). In these sizes, you should find Michelin, Pirelli and Bridgestones tires.

kev951

Why are you trying to go MAX wide for street? lol.. also what year is your turbo... offset determines wheel choices or spacers..