trackjunky

OK, so I'm trying to make those final tweeks to my car. I thought that it would be a good idea to get the track width front and rear as wide as I could and stay within the fenders. After measuring, I ended up adding a a 23mm spacer up front and a 7mm spacer in the rear. The wheels and tires now fill out the wheel wells. I am running 8x18 fronts with 225's and 10x18's with 285's in the back. After the last DE I had the car really dialed in and it was pretty neutral.

My question is, what will widening the track width front and rear at the rates I am adding do to overall handling?

(Track width with spacers is now 68" front and 70" rear.)

jrgordonsenior

Roll the rear fenders too and run a 15mm back there with the 5 spokes. Why aren't you running the 245 up front with the 285 rear?...

PS: I have 2 sets of the OEM 5 spokes for $1k per if anyone wants a set....

trackjunky

I had been running the Toyo R888's and the 245 is about 3/4" taller than the 285, so I went to the 225 which is the same diameter. A 15mm spacer in the back would put me over the 70mm track width buy about 1/2". (Spec 996)

mdrums

I'd get wider wheels for wider tires....255-35-18 front and 315-30-18 rear.

Did you put GT3 Cup lower control arms on? They will also give you a wider front track.

onefastviking

I wouldn't use that large of a front wheel spacer, but you never seem to listen to me anyway.

What kind of lap times are you running in it now ?

bobt993

^^^^^^^^^^^^^^^^ Listen to good advice.

Your messing with the scrub radius. If the car is optimal and being driven really hard then this will be a big problem. Wider cars with wider tires do grip better, but there are ways to do this properly. The rear is not the problem, but the front is.

trackjunky

Well, you did tell me to get the wheels as far out as I could.

My gut tells me that 7mm rear and 7-10mm front is where I should be. H&R doesn't make a 10mm spacer so it would be 7mm or 14mm.

Thoughts?

My question is what effect would I see if I were to drive the car with the spacers that are on it now? My guess is that it would have real precise turn in, with a heavy steering wheel feel and be more prone to making the rear loose.

Land Jet

[QUOTE=bobt993;7455819] Your messing with the scrub radius. [QUOTE]

Could you explain this for me? I've only heard this once before and then it didn't have any explanation either. Thanks.

I've been running 7mm front and 15mm rear spacers with stock wheels and tires without detrimental effects, at least as far as I can tell.

Potomac-Greg

[QUOTE=Land Jet;7456155][QUOTE=bobt993;7455819] Your messing with the scrub radius. 2nd. I'd like to hear more. I run early offset wheels on a late offset 944 which has the effect of a sizable spacer (2cm?). I realize that scrub radius is affected. But I also assume that it reduces effecting spring rates (essentially lengthening the control arm), and may put more pressure on wheel bearings.

Cory M

See diagram below for the geometry. Increasing the scrub radius will increase the steering effort required. Spacing out the track can also increase the stress on the suspension components. Whether or not it is an issue depends on a lot of factors (amount, vehicle, weight, tires, etc). Increasing track has the benefit of decreasing the lateral weight transfer in corners, allowing you to carry more speed.

trackjunky

Let me throw this out to the Guru's here.

If adding spacers messes with scrub radius (and that being potentially bad), then why is it OK to order wheels with a custom offset and run wider wheels than stock - all in an effort to maximize track width?

LDadrenaline

not anywhere near a guru, but I believe it's because with different offset wheels, the center is always at the same place (as far as where the wheel mounts to the hub). could be wrong though


If it were me, I would put wider tires on the front. you don't need wider wheels. Can run a 245 on an 8" wheel without issues. Also from my experiences, the more spacers you put on the more you put stress on your bearings.

trackjunky

See my third post.

Cory M

If the wheel width is unchanged from stock but the wheels have a custom offset to space them out, it will have the same effect as running spacers. If the width of the wheel increases the location of the center of the contact patch is not the same as spaced out stock wheels.

Larry Herman

Who said that it was? It all depends on what width and offset you are getting. Cory has it on the mark.