Rubbin Wheels Ground Effects

spy23714 · 10-09-2006

I run 245/45/17 sumitomos on my four lugged cobra r's and everytime I make a sharp term, the wheels rub on the front gt bumper. I'm not real sure it is doing anything to my tires but it's really annoying nonetheless. Should I try to shave the ground effects or get smaller wheels and tires or what?

sxrpGT · 10-09-2006

Mine did it on my 89 GT and my 87 GT( same set of 17 inch wheels on both cars) I am running 245/45/17 as well. i have not found a way around it. It only does it when I am turning sharp at slow speeds. Never had a problem at high speeds.'

Drew

**tripleblack** · 10-09-2006

I helped a friend of mine with his 88 that did this. It became a problem after he lowered the car 1.5 inches. We had to grind off about 1/2" of the lower inside lip.

spy23714 · 10-09-2006

If I just shave it off with a grinder with that eliminate my problem? Will it still look the way it should?

**tripleblack** · 10-10-2006

Quote:

Originally Posted by spy23714

If I just shave it off with a grinder with that eliminate my problem? Will it still look the way it should?

There are so many small differences between these cars, I'd be a bit paranoid. I suggest this approach:

1. Get a buddy to sit in the car while you take a flashlight and eyeball the suspect tire while he cranks it left and right. You should be able to spot exactly where it hits (or gets real close).

2. Look for scrub marks on the plastic bumper parts - this should show where you are scrubbing as well (sometimes the tires won't touch unless the car is moving and transfering a lot of weight).

3. Study where its hitting and how far up on the plastic the marks go - if you grind out that amount plus 1/8" more, you should get sufficient clearance. Mark it with a sharpie pen.

4. Check the work area to make sure you aren't getting into bolts, screws or other key areas where the parts attach to the car. If you grind into these points, you may have to drill new holes over about an inch and reattach everything so it doesn't work loose. Hopefully this won't be a problem, but better to check first than repair later.

5. Use some sandpaper to polish down the edges you grind out. Less is more - you can always take more off if it still scrubs. Take your time. Play some good music on the stereo. Touch up the plastic that you expose with some touchup paint (just for looks, really - the plastic won't rust).

I never asked, but are you using the stock wheels? Wheel offset has a lot to do with this problem as well. If you are planning on replacing wheels soon, I'd wait - your new choices might eliminate the problem (or make it worse - offset is the key - discuss this with the seller).

Good luck

shakerhood · 10-11-2006

I was going to say the same thing as the above Post that says the Offset is Wrong on those wheels for your car.

spy23714 · 10-11-2006

How do I adjust the offset?

**tripleblack** · 10-11-2006

Quote:

Originally Posted by spy23714

How do I adjust the offset?

You can't really change the offset of the wheel - it's the way the wheel was made (offset refers to the spacing built into the design of the wheel, usually as measured from the spindle or axle).

Wide, aftermarket wheels (or wheels intended for another year model) are the usual culprits.

Some people add spacer rings (I don't like them, and I don't recommend them anyway) when what they need is MORE offset. I suspect your problem is that you already have too much to start with.

There are thousands of wheels that will bolt on a car, but most won't have the correct offset to match the car and/or tires. Its a common problem.

When you do the exam to see where its scrubbing, make sure its not also hitting your brakes, brake lines, or steering components (tie rod ends and such). If they are, you may be better off with new wheels.

spy23714 · 12-21-2006

I've got 245/45/17's now. If I adjust to a smaller tire, maybe a 235 or even a 225, will that help the tires from rubbing on the effects?

shakerhood · 12-21-2006

Quote:

Originally Posted by spy23714

I've got 245/45/17's now. If I adjust to a smaller tire, maybe a 235 or even a 225, will that help the tires from rubbing on the effects?

Again it really depends on the Wheels you have.

spy23714 · 12-22-2006

Well I'm keeping the Cobra R's because I'm unable to afford anything else at the moment. Should I stay with the 245's or go smaller anyways?