Aftemarket wheels and tires for roadracing

[Suprastudy]

Originally Posted by pwpanas

Yes. Be sure to check the rim diameter you need to clear the brakes. Next, check the sizes of the tires that you plan to purchase and use. You may not be able to get near-optimal 275s or 285s in the front, and 315s in the rear. Maybe you'll end up with 265s up front, and 295s or 305s in the rear instead. Also have one or two back-up tire brands/models in case the company stops producing your first choice. Lastly, get the rim widths to match the rubber you'll be running. When you come close to your decision, please feel free to post here, and we'll provide feedback.

Low profile, wide front tires will give you a MUCH more responsive turn-in. You'll be shocked when you switch from oem 235s to 275s or so up front. Of course, it'll be a bit harder on your power steering, so be sure to follow proper maintenance, and use good fluid (eg Redline Power Steering Fluid).

Hypothetically, if you widened the back tires, and kept the oem front tires the same width, it'd push in the corners (i.e. turn-in would be less responsive). That's why you have to upgrade both the front and the back widths simultaneously and proportionally.

I fully agree with pwpanas serves on point with the info.I am currently deciding to go with 9 x 19 with a +43 offset front wrapped in 265/35/and rear 11.5 x19 with +44 offset with 305/40/19 problem is I don't know how this will look nor how much body modifications I am gonna face.Any help?

[pwpanas]

Originally Posted by Suprastudy

I fully agree with pwpanas serves on point with the info.I am currently deciding to go with 9 x 19 with a +43 offset front wrapped in 265/35/and rear 11.5 x19 with +44 offset with 305/40/19 problem is I don't know how this will look nor how much body modifications I am gonna face. Any help?

I can't answer to the offsets without going thorough some calcs. I'd recommend you have the company or person you purchased the rims from to guarantee fitment...especially proper clearance from the suspension (but not too much!). The wheel/tire should actually touch on the oem suspension when the car is up on jackstands and the wheels are hanging down as low as possible. With coilovers, there is still a tiny bit of clearance when the wheels are hanging at their lowest point.

However, I can tell you about the body modifications. Actually there is only one modification: Just get a reciprocating saw or a jigsaw and cut the rear fender inner lips. Tape it off beforehand so the paint is protected. Go over it afterwards with a grinder to ensure no sharp edges. Spray paint it afterwards so it doesn't rust. Done. I've done it dozens of times on Mkiv Supras, and the fender is no weaker than before...and you can barely tell its been modified unless you know exactly what you're looking for. Done right, and with the right offsets (I'd recommend +50mm for 11.5" width rims) 315mm width rubber fits perfectly with no rubbing at all (assuming stock-ride height suspension).

A few more details on the cutting process itself:


Basically you will cut a smooth line from the body joint in front of the rear tire to the back of the rear tire, over the top (of course). You want to trim away as much as possible (really!) - there shouldn't be more than 1/8" left of the lip on the extreme inside (when you curl your fingers around and feel downwards from the top). Across the bottom edge will be closer to 1/4" or so. Of course, there is no change at all to the outer (painted) fender. This nearly complete lip removal maximizes the clearance for the tire as it moves up and down with the suspension.

• From the starting point at the body joint, do a relatively sharp curve to that max lip cut width
• Follow that max lip cut width *straight*, up and over all the way to the back joint
• do a relatively sharp curve back out to the opposite body joint
• It helps to draw a line on the tape that you used to protect the paint (eg. with a sharpie)
• Be sure to angle the reciprocating saw's blade slightly so the tip of the blade doesn't hammer into the inner fender (at a point beyond the lip) and keep that angle consistent throughout the cut.
• Again, be sure to go over it with a grinder to round off the sharp edges, and then primer+paint afterwards.
• Take a look at the attached pic for reference.

Got it? If not, please post or PM me with any questions.

Oh, here's what not to do:

• Don't try to"roll" the fender lip. The fender lip much too stiff and will distort the fender if you try (yes, even with an expensive fender rolling tool).
• Also, don't try to cut the lip with any sort of grinding wheel or dremel. This puts too much heat into the fender and will (likely) discolor the paint. Even with a reciprocating saw the fender will get quite hot - if you have a buddy helping you, you can keep the paint cool with wet rags while you cut with the jigsaw or reciprocating saw.

[ttsupramiv]

hi pwpanas, my set up for my mk4 tt 6 spd.
front: 18x8.5 + 45 ( 245x40x18 )
rear| 18x10.0 + 50 ( 295x35x18 )
it that good? or bad?
thnx.

[pwpanas]

Originally Posted by ttsupramiv

hi pwpanas, my set up for my mk4 tt 6 spd.
front: 18x8.5 + 45 ( 245x40x18 )
rear| 18x10.0 + 50 ( 295x35x18 )
it that good? or bad?
thnx.

I'm sorry to say that I don't really consider that much of an upgrade over the oem rims. The oem rims are 8" wide in front and 9.5" wide in the rear. If you're going to spend the $$$ on aftermarket rims, why not go with something substantially bigger? I consider 9.5" wide in front and 11.5" wide in the rear to be a bare minimum. With fender flares (eg. Veilside) you can run even wider rims.

What is your horsepower spec? If you're still running the oem 320rwhp with the oem twin turbos (i.e. not BPU, etc.), then perhaps those rims really are okay...