Trailing arm rubbers clearance

[Arthur 20]

Hi all.

 

Wondering whether you can help. 2 years back I made my own trailing arms from 35 x 2,5 (25crmo4) pipe. Since the inside is then 30mm I had to get creative with the rubbers. Since the standard rubbers are 32 and 28 mm they do not fit. The rubbers of the rear beams are 30mm though. They look and feel the same, yet there is less rubber and a bit more empty space in the whole assembly. I took the gamble and took these rear beam rubber for my front arms. 

 

All was good at first, but now 2 years later I think the rubbers are getting tired. The car starts to get increasingly nervous at high speed. (Pulling left to right on and off the throttle) According the wheel alignment tutorial here, maybe a bit more toe in might cure it. I tried this and it does, but then I think it's just too much. After all 2 years back it was fine. (I'm running about 2,5 camber)

 

I'm going to order custom shore 90 bushes now, but I'm wondering. 

 

Provided the steel bush and bolt is fine; how much play should the rubber itself have? When I check this, I can quite easily get 1mm from the rubber itself. More on the right, and my feeling was that side is the problem, so I think this is the culprit. 

 

Does running 2,5 camber influence the amount of toe-in compared to standard? From the tutorial it's like 0 deg is good turn in, yet nervous, bit of toe in and it's better at high speed, yet less pointy. Do I need to add toe in with more camber? 

 

 

Edited January 20 by Arthur

[welshpug 1,710]

I would sleeve the bore down to 28mm and use a wishbone bush, the rear crossmember bushes arent intended for a twisting motion.

[Arthur 20]

Yeah, would have done that if the other wasn't 32 mm. Well, failure is also a result. I guess it's because the rears are partly hollow. 

[Arthur 20]

So indeed the rubbers were quite shut. I have some original front ones laying about and they are just as firm as shore 90 poly from the feal of it. In hindsight it wasn't a wonder the rubbers intended for the rear didn't hold up.  

 

 

 

 

 

 

Edited January 27 by Arthur