Manta Tire Rub

[neuropel]

Looking for advice on my Manta. I'm running 195/50/15 tires on 15x7 rims with +28 offset and I'm getting rubbing on the driver side rear when I go over bumps. Same combo on the front clears with no problems since I trimmed the valence panel. Suspension is lowered 1.5"-2" and has KYB Gas Adjusts, but I got the same rubbing before the suspension mods with stock springs and shocks. The inner lips of the fenders have been rolled up and I can fit my hand between the tire and fender, so I'm thinking it's rubbing on the inside (sounds like it too). So, what's the max tire/wheel combo that will fit under the rear fender of a manta?

Todd K.

[RallyBob]

Originally Posted by neuropel Looking for advice on my Manta. I'm running 195/50/15 tires on 15x7 rims with +28 offset and I'm getting rubbing on the driver side rear when I go over bumps. Same combo on the front clears with no problems since I trimmed the valence panel. Suspension is lowered 1.5"-2" and has KYB Gas Adjusts, but I got the same rubbing before the suspension mods with stock springs and shocks. The inner lips of the fenders have been rolled up and I can fit my hand between the tire and fender, so I'm thinking it's rubbing on the inside (sounds like it too).

With a 28 mm offset, I'm calculating roughly a 5.1" backspace and roughly 1.15" further 'out' than stock 1974 Manta wheels, which is not much at all. They should fit with ease.

Did you ever check to see if the panhard bar is bent? Either way, if the car is lowered I'd throw an adjustable one in there to center the axle under the chassis. I'm sure this is at least part of the problem.

So, what's the max tire/wheel combo that will fit under the rear fender of a manta?

You really had to ask? Just recently mounted, and test-fitted under the 'Turd's' rear wheelwells. 13" x 9" wheel with 6" backspace (no internal rubbing), and a 245/50-13 tire (22.64" tall). Your 195/50-15's should be about 22.67" tall, so we're nearly identical there.

Bob

[neuropel]

Originally Posted by RallyBob Did you ever check to see if the panhard bar is bent? Either way, if the car is lowered I'd throw an adjustable one in there to center the axle under the chassis. I'm sure this is at least part of the problem.

Interesting one there...I had the same rubbing with the stock suspension and same wheel/tire combo but had assumed it was partially due to my worn out shocks. Would the panhard bar need to be visibly (or noticeably) bent for this problem to occur?

Perhaps it's just my fat a$$ making it rub, kinda like a fat chick in corduroy...

In all seriousness, I'll pull the wheel tomorrow and see if I can spot any rub marks. Do you know off the top of your head which way the suspension shifts when it's bottoming out? I have an adjustable panhard bar but I've been saving it for my other Manta. The car from which I got the suspension (Duane's old white car) didn't have an adjustable bar, but I'd guess he never ran anything bigger than stock tires.

One thing though...the car *really* handles nice now!

Todd

[RallyBob]

Originally Posted by neuropel Interesting one there...I had the same rubbing with the stock suspension and same wheel/tire combo but had assumed it was partially due to my worn out shocks. Would the panhard bar need to be visibly (or noticeably) bent for this problem to occur?

Typically it will be obvious to the naked eye, yes.

Perhaps it's just my fat a$$ making it rub, kinda like a fat chick in corduroy...

Thanks for the visual....

In all seriousness, I'll pull the wheel tomorrow and see if I can spot any rub marks. Do you know off the top of your head which way the suspension shifts when it's bottoming out?

When a Manta is lowered, the left outside wheelwell will tend to interfere first, as the axle shifts to the left.

Another possibility is simply chassis variation. I've seen a few cars with oddly overlapped seams or other areas that protruded in one way or another.

Bob

[madhatterpdc]

I think you're beyond these suggestions at this point, but just in case. Tire rubber gets marked up pretty easy, so just a few rubs and you should be able to read some clues off the tire. Also, you can force suspension compression by jacking the car up at the opposite corner. Naturally this method doesn't give the most linear travel of the tire, but it gives you a few more clues what might be going on.

Also, make sure the fender opening is square and clean. (nevermind, just re-read that you've rolled the fenders).

[neuropel]

Sorry, I lied...it's the RIGHT rear tire that I hear scrubbing (duh). Still makes sense that it could be the inner portion rubbing if the rear end shifts left when lowering. I probably will jack up each front corner tomorrow and see if I can spot where it's touching in the rear, and also closely check out the panhard bar. I guess the really tough question will be what am I going to DO about it. I've already looked for scrub marks on the outward face of the tires and they appear to be clear.

Todd

[GTJIM]

Jack up the back of the car and rest it on jack stands under the rear jacking points - now; remove the rear springs so you can move the diff through full suspension movement.

You will be surprised how much the wheels (diff!) move from side to side.

The Panhard rod needs to be set up so that it is parallel to the ground when a full tank of gas (and your corduroy clad ass!) is onboard. If this adjustment is not right the diff will just move further and further to one side though out the full suspension movement.

You need about 1" of minimum clearance between the both sides of the tyres and the sheet metal to allow for further movement due to side-loading during cornering.

HTH

[oldopelguy]

Bringing this thread back from semi-retirement, do you happen to know off-hand the maximum backspace for the front of a Manta as well, Bob? I've got some extra 9" wide rims I'd love to mount on the front of the Ascona you see....

[RallyBob]

Originally Posted by oldopelguy Bringing this thread back from semi-retirement, do you happen to know off-hand the maximum backspace for the front of a Manta as well, Bob? I've got some extra 9" wide rims I'd love to mount on the front of the Ascona you see....

Any more than 5" backspace up front and you have to start looking at wheel-to-upper ball joint interference. Larger diameter wheels (15"+) are less prone to this issue, but at some point even those might contact the upper a-arm while turning the steering wheel.

[Phoenix]

Originally Posted by neuropel Perhaps it's just my fat a$$ making it rub, kinda like a fat chick in corduroy...

I almost choked reading this.

All very good reading. I'm worrying about this right now myself.