306 Rear beam

Looking for a 205 GTI beam tube in good working order? I'd cut and shut a 306 beam if you can't find one. There are lots of good 306 beams around but not many 205 beams. Eventually you'll need to do something different when 205 supply dries up. Shortening a 306 beam is one example. Repair welding and re-machining a 205 beam is another. 306 beams are otherwise identical.¹

306 ARB

The 306 has 2 different sized end plates for the ARB: a 24mm and a 25mm end - remove both end plates and measure the bar against the 205 ARB and mark where the 205 bar ENDs on 25mm end of the 306 ARB.

Double check you have the correct end, then cut the bar. Clean the now cut arb and clean the 25mm end plate. Insert the cut end of the bar into the end plate and slide it all the way to the end. You will find it sleeves nicely into a 306 end plate (which fits a 205 beam). Now weld the end plate to the bar. You will need 306 end plates for both sides: the 205 end plates are too small to fit on the 24mm bar splines.

It's critical that you align the two ends with the end caps on before you weld to make sure end plates will mount properly - as the cut bar end rotates in the end plate it's pretty easy to do if you have a nice flat surface ( just put the other endplate on before welding). Make sure you weld it in a position so that the plate the other end sits level on a spline.

The downside is you always have to remove from the welded side, but you now have a cheap 24mm ARB for the 205.

Same thing can be done for the 309 and 405 (I think).

The 306 s16 and gti-6 both run the 24mm ARB. Some of the Citroens also would no doubt.

Its not too large when you consider the 106 gti and saxo also run a 24mm ARB factory. I used it on my 205 with factory torsion bars and it was awesome... ²³

Or do it properly and re-spline.⁴