BigD New Reader
July 25, 2010 9:54 a.m.

I have problem with my new slicks where under hard cornering, the tires rub on the inside in the rear. I can't space them out any further, plus I'd rather stiffen up the arse. I have the GC coilover kit, which is not a true coilover in the rear. I currently have 750lb springs there. What are the stiffest I could go with without overwhelming the shocks?

I've been told by GC that I can run about a max 600 lb spring front, which is a true coil over. So I'm guessing this means I may be able to run like a 900-1000 rear?

Some visual aid for non-BMW guys to see the relationship of the spring perch to the shock pickup (top right) and the pivot:

mw HalfDork
July 25, 2010 9:16 p.m.

You could call Koni. They would at least know what the shocks are able to handle in a coilover situation. Then to figure out the spring rate needed take off the spring. Then measure hor far the shock moves through it's range of motion. Then figure out how far the spring seat moves through that same range. Do a little math and you e got your answer.

July 25, 2010 9:35 p.m.

With an E30, you hit a point right near 800 or so where adding more spring isn't really doing anything but flexing the chassis and control arm bushings more (think of it as a pliers...). They handle pretty well right there also... to solve your tire rubbing issue is another matter... one usually solved with a different offset, spacers and Ireland's flares. (or if you are me... a big berkeleying hammer and some paint).

BigD New Reader
July 26, 2010 9:33 a.m.

Thanks guys. I've got a half cage with the rear bars tied in roughly to the spring perch locations so I'm hoping the rear end is stiffened up some. The bushings are all urethane. I will be adding fender flares next year with a change in the suspension and wheels/brakes so I'd rather do something that can be used later. GC just replied to me saying that the rear wheel rate is about half and the Konis can take about 650 pounds so 900 in the rear is fine... so I'll try that.

I'll also see if I can introduce Capt Sledge to the rubbed areas for a quickie.

You'll need to log in to post.

Also on Grassroots Motorsports

Concours d’Lemons: Showcasing the Best of the Worst and the Worst of the Best

8 hours ago in Articles

This year’s Concours d’Lemons celebrated two cars rarely associated with the glitz and glamor of Monterey.

Your Projects: Wide-Body, V8-Powered Porsche 944

8 hours ago in News

Wing, flares, V8 swap and more!

Acura Unveils New Prototype Race Car in Monterey

16 hours ago in News

Acura yesterday unveiled the new Acura ARX-05 prototype race car.

We're Back In Monterey for Car Week

1 day ago in News

And so it begins, another trip to Monterey Car Week.

Mark Your Calendars: August 18 Is Wear Your Helmet to Work Day

1 day ago in News

Wear your racing gear to work and win prizes.

You Need This: A Real 1LE Camaro

1 day ago in News

Chevy only built 62 1LE Camaros that year.

Little Car Show: Celebrating All Things Quirky and Small

2 days ago in Articles

As the name suggests, the Little Car Show is all about little cars.

Concours d’Lemons to Ruin Monterey Car Week Yet Again

2 days ago in News

What started as the anti-concours has transformed into a major event on the Monterey Car Week schedule.

You Need This: A Quite Eye-Catching Green Over Red Ferrari

2 days ago in News

Not your usual Ferrari color combo.

Your Projects: JDM Autozam AZ-1 Kei Car

2 days ago in News

What are the realities of importing a JDM kei car to the U.S.?

Bid on a New Helmet and Save Some Puppies and Kittens!

2 days ago in News

Four helmets will be auctioned off.

Tonight on Grassroots Motorsports LIVE! Lee Grimes of Koni Shocks

3 days ago in News

This may shock you, but suspension is arguably the most important part of going fast.


Grassroots Motorsports Magazine

Subscribe Today

Also get your instant access to the digital edition of Grassroots Motorsports Magazine!

Learn More