poly bush

[had17462]

Hi all ,could anyone give any advice on poly bushes ,iam about to build up the chassis,regards nick.

[Richard Crawley]

All I advise is be careful which bushes you use & how far you go; go too harsh & you may totally regret it & then you need to check your private dental care & ortho-pediatrican are fully paid up!

[had17462]

Richard ,did you put poly bushes on your 6 or just certain ones,

nick.

[Richard Crawley]

I’m still running (new) rubber bushes at the moment; in good condition with the Spax gas & modern low profile tyres, they are quiet firm enough for me. The only criticism I have is the rear end is a little too axially compliant for spirited driving which can make the car a little skittish on bumpy corners if you’re not careful.

 

I will probably go to Polybush when I have to replace them but only the more compliant “road” variants & I may even keep part rubber on the front wishbones. You just need to think a little before jumping in with “improvements” on a classic car or you will completely change its character. Like so many other “mods” it’s so easy to get carried away & end up with something you may inevitably be disappointed with; or maybe not if that’s what carries your bag!

[Guest Wyn]

I had to take a second look at your posting Richard, you with low profile tyres??

 

Wyn

[jerrytr5]

I use poly bushes throughout except for the trunnions which are nylon anyway and don't need poly (and when I did try poly they didn't seem to fit).

Using poly means that the suspension moves only in the plane (more or less) that it's intended to and whilst this may affect the NVH (noise, vibration, harshness) attributes, your choice of springs and dampers are likely to affect your dentistry rather more .

Jerry

[Richard Crawley]

I had to take a second look at your posting Richard, you with low profile tyres??

 

Wyn

I really don't have problem with running low profiles (within reason!); my main concern is not exceeding the specified tyre widths for whatever width rims you have fitted & not overloading a near 60 year old suspension design.

 

Mine are only 185/65’s on 5 ½ J Minilite replicas; now wish I’d gone for 6J with 195/65’s but TRGB didn’t have them in stock at the time & I desperately needed wheels to get the 1st MOT done so I could drive the thing again after 18 years!

[Guest Wyn]

My comment was very much tongue in cheek Richard, couldn't resist it!. I originally had 5 1/2J with 185 x65 and subsequently changed to 6J with 195x65 which looked much nicer on the car, both now gone for my new ones which I intend to keep.

 

Regards,

Wyn

[Tom Fremont]

I changed to 6J with 195x65 which looked much nicer on the car

 

My choice too, and swapped out the 3.7:1 diff for a 3.45:1 to compensate. Tyre choice was limited to " performance " rather than " high performance " or " ultra high performance " but who's kidding whom, the Michelin Pilot Exaltos give excellent account of themselves on the TR with far better manners than the original ( U.S. spec ) 185/80-15 behemoths.

 

I agree with Richard's choice on bushings from a ride standpoint, though both of my cars are poly bushed now. I wasn't happy with a failure on an original type front bushing after ~45000 miles so changed them out to poly, which now squeak but which may yield to spray lubricant therapy in time . The rears seem to last a very long time so I can recommend the originals there even with poly in front.

 

Here's a question: alignment specs call for toe-in on both axles. Given the compliance of the original bushings I wonder if the toe-in is intended to let the wheels go parallel in motion, as the rolling resistance will tend to cause toe-out. So should the toe-in spec be reduced for less compliant bushings ?