handling with relocated springs?

[Beck]

hey guys,
i got a quick question:
does anyone have first hand experience with a change in handling (negative or otherwise) after relocating the rear springs with a dr diff kit or similar?
i'm planning on pushing my leaves in an inch so i can fit my tires better, but have been told this can have a major negative effect on handling, ie more body roll, less stability.

cheers,
aaron

[mopar12372]

i had no change in handling from the relocationkit. it all in what shocks and tires you use , try not to mix byasply tires with radial tires and youll be just fine INMYOP

[matt63]

I wouldn't think that the offset shackle kit would make a huge difference but moving the springs over 3"/side sure will IMHO.  If you're building the car to go around corners fast this would not be the thing to do.  I'm in the process of doing the latter to my '68 Valiant so I'll find out. 

[Chryco Psycho]

I agree the effect will be minimal especially if the spring sits close to flat

[HP2]

To find out the change, you have to measure the distance between the spring mounting pads then divide that by the track width of the rear end, then square the result. That give you the motion ratio of the spring force. Multiple the motion ratio by the spring rate, and that is the wheel rate applied at the tires. Then repeat for the new location and notice there is a change, but there is not a big enough change to really notice, unless you have spent decades in competition cars acclimating yourself to these types of subtlies.

So, for a stock E body with zero offset wheels and XHD springs; 46/61.625,squared equals .556*140 equals 77.84# of rear wheel rate.

Now move the springs in 1 inch and leave everything else equal; 44/61.625, squared equals .508*140 equals 71.17# of rear wheel rate.

Lets move them in 3"; 40/61.625 squared equals .421 * 140 equals 58.9# of wheel rate. Or enough to start noticing, if you really know your car well.

You can add sway bars to start cranking the rates up, but that is a whole 'nuther set of calculations.

[Katfish]

I did the Dr Diff 1" kit.  Also changed to 18" rims in back (6" BS).  I can't tell any difference, but I'm not really pushing the car very hard in any corners.  Mainly just straight line everyday cruising.

[Aussie Challenger]

     Small amount moving the springs won't affect handling that you will notice unless you are on the limit all the time.    
  Install a rear sway bar and improve the handling, don't forget to use quality shockers as well, the larger tyre/wheel will add to the unsprung weight slightly