I've come to the point of putting the the top mounts for all the shocks on my scratch build, I've heard various figures like the car should stand at an inch of suspension travel. Are there any rules of thumb or methods I can use to get the correct mounting locations...


I think i'm going to try and aim to have all wishbones level at rest...

James

Check my post in this thread and get a copy of the book

CLICK HERE

"In general" at normal ride height with all fluids and driver aboard, you want the shock about half compressed, or maybe a bit less, so 40-50%.

Oh and you should have "about" 3" of *wheel* travel before hitting the bump stop.

All these numbers are subject to great argument, but it's working fine on my car. It very much depends what road surface you drive on and how firm a ride you can stand.

thanks kb58, just the info I was after

James

Sorry to reopen this one, but what clearance do most sevens have when right down at bump stops on the suspension?

James

anyone?

What clearance?

Ground clearance i assume... most have it set between 3" on track and up to 6" for the road at ride height. What that would give at full bump i dont know.

David

sorry. yes its ground clearance on the bump stops i'm after....

anyone? even a guesstimate?

Basically i need to know whether i hit the bump stops with the chassis just clearing ground or whether i need to be and inch or two up.....

I presume this is harder for people to check than I thought

James

On the bumpstops, my sump barely clears the ground.
Guess that means the chassis, at that point, is about 1 1/2" from the floor.

Many thanks Marcus - that's all I needed to know, i'll get those mounts welded in tonight

James

What you're asking has no black-and-white answer. It all depends on your car's application, what the roads are like in your area, if you have to drive over fallen debris, speed bumps, pot-holes, railroad tracks, driveways...

OK I've welded them on, it gives about 1" clearance with the bumps fully squashed and 2" as it starts to hit the stops

This gives just over 10cm of suspension travel, with the car resting at about 6cm, leaving 4-5cm of upwards travel.




am I going to get away with this based on the photo + measurements above or do I need longer shocks?


James

[Edited on 31/10/06 by cloudy]

Pickup point for coilover on chassis will bend.
NEVER feed loads into the chassis like that.
Wishbone pickup points in tube if not braced (triangulated) will distort chassis.
Sorry for the bad news, but better now while it can be corrected.

I think you will find that the angle that the shock is at will also give you problems with a falling rate spring IIRC the spring should be as near 90 deg. to the suspension travel as possible and by the looks of yours it's about 45 degrees

Weld a bar across your top wishbone and gusset a top bracket wherever you want it on the chassis member then run your shock wherever you want it to make the ride height right. Sorry for the rough drawing but I hope you see what I mean. edit here:- or if your dampers are 12" open 9" closed get some longer ones and I'll take the old ones at a greatly reduced rate.

[Edited on 1/12/06 by Peteff]
Rescued attachment suspension.jpg

Hey,

I'm agree that the chassis will bent at the top mounting pos.

I want to argue that the coil-over in front of the car (most) are also not 90 degr is placed.

If you want to place the coil-over as suggested by pete you have to make a strong wishbone.

I like the idea to keep the coilover as close as possible to the upright.

In this case i would search for longer coilover and made a lot of enforcement on the upper coil-over mounting try to get the forces in the coilover al in line with the forces into the chassis.