Looking for rear suspension a-frame and supporting assembly dimensions

Happy Weekend Gents, I have searched this forum and Googled a bit but can not seem to find any dimensional specs for the GT40 spaceframe rear a-frame and supporting assemblies. I believe I have what I need for the rear upper, I just need to get dimensions of "mainly" the rear a-frame. But all assemblies (bars connecting to the upright from the frame) would be great.

Pretty much the moving pieces in this video.

My half-axles have arrived and I have test-fit them to my 10Etranny and test fit that with KED adapter and Ford 302 bock into my frame. It is time to start mocking up the rear suspension.

Can anyone help me out on this? I plan on fabricating this myself at home.

Many thanks,


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Mike Pass

I can measure up on my GTD if that would be OK for you. I assume you will want the lengths from the centres of the pivots at each end?
not mine found on the net,
if of any use


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Mike Pass. Absolutely. That would be perfect. My frame is a GT Forte' and I have it tacked up until the shell arrives. However, I need to have the wishbone assembly and rear uprights on the front burner. I can take your measurements and pump them into CAD and toy around a bit before mocking one up.

I really appreciate this Mike ^^

Mike Pass

Measurements from GTD.
Top trailing arm length 775mm goes up to chassis at 2 degrees - distance from upright mount centre to centre of top arm upright mount is 100mm
Bottom trailing arm 670mm goes up to chassis at 3 degrees
Top arm 280mm angled down to chassis at 10 degrees
Bottom reversed wishbone - from chassis to line of outer pivots 375mm - distance between centres of outer pivots 260mm - angled up to chassis at 4.5 degrees
The bottom trailing arm mounts to the upright 110mm higher up the upright than the lower reversed wishbone.
A few pics of a different GTD as my rear clip is in the way so you can see the arrangement on the GTD.
Hope this helps. If you need any more measurements let me know.


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Mike. I am going to use this Sunday fabricating pieces out of PVC using the measurements you have provided. I really appreciate this Mike..

Thank you ^^

Mike Pass

Those are for standard GTD setup. I would suggest raising the inner end of the top link by 20 -25mm as the standard setup has too much camber gain in bump. i.e. top link angle is too steep at 10 degrees. I don't know what you are going to do with the car but if you are going to do track stuff I would suggest you need to look at the front wishbones as they have been known to bend and break. One of our guys here in the NW UK has made his own uprated wishbones. Bob's build log here.
Set the rear suspension with very small amount of camber and toe-in. Normal ride height front chassis to ground 4", Rear 4.5"