Compomotive on E.M.......

Melzer · #1 (**permalink**) 03-11-2003, 10:15 AM

Looking for opinions on changing backspacing/offset on (rear) Compomotive pin drive wheels mounted on an Everett-Morrison.

I'm trying to get the rear wheels under the flares a bit more so that the rear can be lowered over the tires to sit (squat) correctly.
I have talked to a Compomotive rep and he indicated that the wheel can be narrowed by 1/2" increments and backspacing can be shifted by the same increments.

The rep was very helpful and said that I could send my wheels to him and they could make the necessary modifications for a very reasonable fee. The catch is this, it's my call to make regarding the amount of backspacing/offset to be made. I don't want to go too far inward with the wheel yet need to get the tires under the body enough to accomplish the end result.

My concern is with the tire or wheel inner surface contacting anything after shifting the backspacing inward. Are there any guys out there who have done this? Running a 295 tire with Jag XKE rear, inboard brakes.

Thanks in advance........Mel

Tom Wells · #2 (**permalink**) 03-11-2003, 10:34 AM

Hi Mel,

What I'll suggest is a lot of work to do. It may save you a bigger bunch of headaches later

The place my tires rubbed first were the backs of the seat buckets. I have the 17" wheels with 315-35/17 tires so their profile is a bit more square than yours.

Get the car on a lift. Start measuring distances to the nearest bodywork. Odds are, it will be the bulge in the seatback which will contact the innermost edge of the tire's tread.

Here's the sure way to do the next step - also the most work: Remove the shocks on one side - maybe only the lower ends of the passenger side shocks would do - and let the car down as far as the shocks can compress (you do have this minimum dimension in your notes, don't you?

). You'll directly see what will hit first, and when.
If nothing hits, you're in business and can measure the minimum clearance.

Then you can calculate how far you can move the tire inward and still remain clear of contact at full spring compression.

Sorry, don't know of an easier way to do this!

The alternate way is also work: get a wheel/tire assembly of the dimension you think will fit, install it and compress the suspension. Check clearance.

My E-M is a 2001 version. If yours is much older it may be shaped differently underneath, so take the seat bucket first contact point guess as just that!

Hope this helps!

Tom

A Cobra guy · #3 (**permalink**) 03-11-2003, 01:22 PM

I have an E.M. with the Lincoln MK8 IRS. The wheels are 15" 5 bolt with Goodyears. The 1st season the tires rubbed exactly where Tom said, just behind the seats. This was the inside sidewall during cornering. In my case a 1/8" spacer did the trick. In your case I don't think spacers are an option if you get the offset wrong.

You may not get to lower the car unless you go with narrower rubber. With the spacers I would say the tires are in as far as they can go. They are barely covered by the lip of the fender. I can fit my fingers between the tire and body but not the palm of my hand. I am happy with the look of the ride hight but realy doubt I could lower the car much if any. It has yet to rub with this setup even while autocrossing.
I'm not sure if any of my pictures show this rear ride hight but you could check.

Good luck.

Harvey R.

Melzer · #4 (**permalink**) 03-11-2003, 05:17 PM

Tom....

It seems the 1st method you mentioned is a winner. Even though it entails some work, anything less will probably result in more aggravation down the line. I'll give it a try....I like the idea of letting the shocks loose to actually see where the body will make contact. My EM is a 1990 vintage model so I don't know what impact it will have (if any) on the game plan.

Thanks.....Mel BTW - do you actually keep the same rubber on that stroker of yours for more than a weekend at a time????

Harvey.....

You mentioned that you have 15" wheels with Goodyears. What size rubber are you running? I am really thinking of replacing my 15" BFG's with Goodyear rubber.....the ones with the BIG white letters. Are these the ones you have? (looked at your pics) all I can say is WOWWWWWWW.....what a paintjob!!! awesome and very patriotic as well.

Thanks for the info.....Mel

427SSSS · #5 (**permalink**) 03-12-2003, 11:00 AM

Mel,
I don't know which rep you talked to at Compomotive, but good luck.

Compomotive Wheels

or

http://www.ffcobra.com/cgi-bin/ultim...=015584#000012

A Cobra guy · #6 (**permalink**) 03-13-2003, 10:14 AM

Mel,
Thanks for the comment on the stars and stripes. The car is normally the classic blue with white stripes. The stars and red stripes were just a light adhesive vinal material. It did look cool but I took it of soon after the photo shoot for fear of it wrecking the paint.
Good luck with those wheels.

Harvey

Melzer · #7 (**permalink**) 03-13-2003, 12:05 PM

Wayne,

Read your previous posts from the links you gave. Ihe rep that I spoke to was in fact Alan of MotorSport Specialties....the same person you dealt with. I must say that although Alan seemed very helpful and sincere on the phone, it did take several phone calls to make contact. He indicated that he could re-work my wheels to obtain a different backspacing/offset and ship them back to me in a short time.

After reading about your experience, I'm not so sure I want to ship my wheels to these people......thanks for the heads up.

BTW.....I hope you get your wheels and they are done correctly

Mel

427SSSS · #8 (**permalink**) 03-15-2003, 06:23 AM

Mel, got my wheels yesterday, with the backspacing I requested.

Sent this email this morning and I copied Compomotive in England

In a message dated 3/14/2003 2:34:44 PM Pacific Standard Time, NDBoyd@usacomp.com writes:

The matter will be closed when you have wheels of the proper offset

No Sir, I do not think so.

Your claim here is misleading. The bulk of the 10 months the wheels were either in your possession, waiting for you or the builder to provide specifications or waiting for payment

No Sir, the wheels were in my possession only a couple of days each time they were sent to me incorrectly.

The wheels were built to specifications provided by you or your car builder. The fact that the wheels were the incorrect backspace for your application was not any fault of ours.

Possibly, the first time. On the second try, I could not get Alan and Jim Riddel, of California Custom Cobras, to call and talk to each other, I tried for at least two weeks. Then Alan said: "Look it's not rocket science, measure from the inside lip of the body to the mounting surface, make sure to allow at least 1" from the outside edge of the body for clearance, and I will take it from there." I gave him that measurement, the wheels came back incorrect.

Again, since the incorrect backspace was not our fault, I would see no reason to reimburse you for freight. In fact, the cost of the rebuilds and our expense for the freight back to you should not really be our cost.

See above.

You can see from the attached thread on FFcobra forum, and the links on that thread to Club Cobra threads, that mine is not an isolated case, that's one of the reasons I disagree with your first response: The matter will be closed when you have wheels of the proper offset

Wayne McAllaster
427SSSS