Offset Rear Axle?

Burgs · #1 (**permalink**) 11-26-2006, 09:56 AM

My body is offset on the frame slightly, and in order to get the stance I'd like, the rear axle will end up offset to the passenger side, as much as 1/2"-3/4" to clear the fender lip. I can keep it square to the frame, but wonder if I'll create problems with the offset. The rear is a narrowed, 9" Trac Loc, with a three link, and a panhard bar.

Rick Parker · #2 (**permalink**) 11-26-2006, 11:20 AM

If you shift the rear axle to one side the wheelbase and tracking will not be "Square", you may suffer some ill handling.
Have you done your measurments carefully? As an alternative could the body be moved on the chassis a minor amount?

Where did you find the Avitar?

Burgs · #3 (**permalink**) 11-26-2006, 11:48 AM

Rick, All of the swinging panels are frame mounted, and finished. Moving the body is not an option. I could do a bit of grinding on the lip and raise the ride height a bit. The measurements are anything but accurate. I installed lower springs in the rear, on my back, car on stands, ramps, and jacks, and my eyeballs aren't what they used to be! I'll get things close, then mess up the front a bit more, and take it back to the alignment shop in the spring. "I don't know what happened,... it just started handling weird!"

The avatar, http://avatars.jurko.net/ but make sure your anti virus is on!

Brad

Rick Parker · #4 (**permalink**) 11-26-2006, 11:58 AM

Primary concern should be sure the tracking is square, the body is then along for the ride. Otherwise it will never handle right and can't be made to.

Excaliber · #5 (**permalink**) 11-26-2006, 12:03 PM

I agree with Rick, line up the axle to frame FIRST. Body being off center or whatever is a well known 'secret' concerning body alignment on replicas. VERY typical for it to be off to one side. It's one of those things 'we' don't like to talk about and it's common to a LOT of makes. You can't really 'see' it, unless your looking for it. You can MEASURE it and once I discovered it on my Excalibur it ate away at me all the time. Even though none of my friends ever noticed the off set, unless I told them.

You will find similiar body slightly off center on a lot of Detroit cars as well. It's the nature of the business I guess.

G.R. · #6 (**permalink**) 11-26-2006, 02:26 PM

Yup re: replica body alignment. The front end of my car is about 1/2" out to the drivers side so the passenger side front tire sits a bit proud of the fenderwell. I don't like it but the correction factor isn't worth the effort to correct so I live with it

Most people don't even notice

(except for the Cobra anal sort

)

Burgs · #7 (**permalink**) 11-26-2006, 02:53 PM

I don't mind if the body is off a bit, It shows up in the clearance from the fender lip to the tire on one side.

It's probably not a good idea to move the front track off center, to match the rear, either is it?

Excaliber · #8 (**permalink**) 11-26-2006, 02:56 PM

A similiar discussion concerning body alignment is also in this current thread:

http://www.clubcobra.com/forums/show...758#post690758

Oh dear, even Kirkhams and Shelbys are 'off' a little.
Solution? Use your tape measure sparingly, you might not like what you find.

Line that rear end up and follow G.R.'s excellent advice, "Breathe in... breathe out..... etc."

LMH · #9 (**permalink**) 11-26-2006, 03:41 PM

Brad
Is the Panhard bar to long at the new ride height?
There is some adjustment to the bar but not a lot if it too long. It looks like you could cut a 1/4" off each end if needed. I wouldn't cut any more though.
Larry

Burgs · #10 (**permalink**) 11-26-2006, 05:28 PM

Larry,

I'm pretty sure Jason cut it down when they had it back in the shop. I've got it lowered to the point it might be too low. The panhard is as short as it goes, and I'm as real close to centered. I need to spend some more time under there with a straight edge, clamps, and some reading glasses.

A lot of honey-do's are keeping me out of the garage.

Brad

496fe · #11 (**permalink**) 11-26-2006, 08:55 PM

Burgs,

I am hesitant to post this because of the risk of getting flamed. I've been road racing a long time now, so I'm just going by experience on the track as well as the street.

Move the axle so that you can get the body down over the wheels. If the axle is off less than 1", that's actually pretty close. Again, from experience, I've found the a live axle moves around considerably more than 1" when on the road with body lean and bumps and all. A live axle is not high tech, but works quite well when set up correctly.

Try to get the panhard bar as close to horizontal as possible when the car is sitting on the ground. An sloped panhard bar makes for evil feelings in corners, especially when they are short. I would direct my efforts at relocating the panhard mountings to get the longest, most horizontal bar possible. The worst feeling is having the rear of the car wiggling around over bumps and in corners because the panhard bar arc is moving the rear end laterally.

If it were my car, I'd be using the waning good weather driving the car, not laying under it

.

JMHO

Burgs · #12 (**permalink**) 11-26-2006, 10:14 PM

Quote:

Originally Posted by 496fe

If it were my car, I'd be using the waning good weather driving the car, not laying under it

.

JMHO

We have been having some unseasonably warm weather, and it appears I've started my winter projects about a month too soon. Another rookie mistake!

I appreciate your stepping in at the risk of the need for fire suppression, but the parallel panhard bar itself is probably the best suggestion yet, aside from driving in late November, in Michigan, when the weather permits. Do you have any tips for the three link??? The bottom two bars run from below the axles, with a choice of three locations vertically, and run forward to the frame. The top bar runs from the top of the axle, offset and forward, towards the rear to a frame mount with a choice of three locations vertically.

Thank You,
Brad

Wayne Maybury · #13 (**permalink**) 11-27-2006, 07:51 AM

When I purchased my Johnex, I was told that the original body used to make the mold was "off" a bit, side to side in the rear. The Johnex uses a live axle that is mounted with a modified DeDion (sp?) suspension which is fully adjustable. Recently a friend who races Dirt modifieds was visiting me and described my rear suspension as a form of a "Z" link setup. This suspension allows me to adjust it just about any which way.

With the live axle right center on the frame, one tire would be about to rub the body while the other one had a good inch to spare. I moved the axle sideways about a half inch and then squared up all four wheels. Now the body appears to centered over the tires. That was 5 years ago and the car has always tracked perfectly straight with no problems. What 496fe said worked for me.

Wayne

Excaliber · #14 (**permalink**) 11-27-2006, 08:21 AM

I hadn't considered the possibility of the body being SO far off it would\could cause a tire interference problem. Whew, there is no easy way out of this. A 'glued on' body is all but impossible to move, but I sure hate the idea of putting the suspension in off center. But as far as a live axle goes, I agree, theres a lot of movement going on anyway.

What about IRS?