The only thread that this was even mentioned was from 2013 (yes, I searched) so it's better to start a new one.

Does anyone manufacture polyurethane bushing sets for VAG Bentleys? The only ones I came across were individual bushes for some suspension arms from Powerflex and Strong Flex, and that's about it. If I calculated correctly, that's 1-2 out of at least 8 total.

I've polybush-swapped a bunch of cars over the decades and while there's a slight tradeoff in NVH for steering feel and accuracy, GTC and Flying Spur can definitely afford that. I'm after somewhat sharper overall feel and maybe slight additional adjustment possibilities by offset bushes. Pretty much all the bushes are shot in the #1 candidate I'm considering so instead of freshing it up with factory parts, this sounds like a much better option. Providing that some can be found; pouring PU casts into OEM arms works but it's messy as heck, a lot of work and may go wrong even if you're careful.

 

Have a geometry set up done and replace the upper control arms , they usually go invisibility and undetected on the inner aspects .
Lowers clunk when worn easy to see as well and determine if worn .Uppers you just loose steering feel .
The difference is like night and day .

 

I do not think it’s necessary at 2 1/4 tons with air suspension the laws of physics are exceeded by some way .The extra NVH will spoil the refinement.
How ever having said that all this weight does accelerate bush degradation particularly the fronts .
The lower inners go first and are easily visible and developed a noticeable clonk over pot holes .U.K. mot ( annual safety check ) usually picks this up , they inspect and pry bar them for lack of firmness .
The two upper inners are deeply concealed and difficult to visually inspect and indeed even pry bar , it’s these that gradually go and loosen the feel at the steering .A suspect a lot are running round with unknown undiagnosed worn ( but pass U.K. mot ) upper inner control arm bushings .

Then there’s the tracking in my experience ( my other hobby cars are 70 s Ferraris ) the BGT is uber sensitive to tracking .I know no other car so sensitive.
The thing is with a proper laser set up where the wheels are put on plates , its often at full lock , from lock to lock that the finite accuracy cannot be obtained because the upper inner control arm bushes have excess play in them ,

At a recent service and U.K. mot with no symptoms they found a torn track rod end rubber so it needed replacement a £40 part .
I asked for the tracking and full geo , kinda volunteered because when running true straight the steering wheel was annoyingly for me off a bit to one side .
The mot tester only found one track rod end torn rubber , it’s was firm but a torn rubber is a fail .
The garage get a mobile tracking guy in .
It was this geo guy who discovered the excess play in the almost hidden upper inners .I agreed for the struts to be removed and all 4 upper control arms + the other none ripped track rod end to be replaced.I,ll add the lowers are pretty fresh about 2 y and 10,000 miles .

Anyhow once new uppers fitted + track rod ends and the proper accurate front end geometry + tracking done .....it’s like night and day , unrecognisable steering feel and front end placement on corners ,Actually a real pleasure to throw around now . A completely different driving experience.

Well worth the effort and expense.
The geo guy was £85 , track rod ends £80 ( one needed doing ) , four upper arms about £75 each and 3 hrs Bentley specialist Labour in all to drop the struts and fit .

I,am on std 19 inch Mulliners btw with 40 profiles.

 

Thanks for the detailed explanation. Fresh bushes and ball joints are a given in any case, but I'm really looking for an upgrade. Not delrin or 90shore+ club sport PU but maybe 80-ish in each and every joint as a very streetable compromise. This is a recipe that has worked for me phenomenally on numerous occasions; from big block muscle cars to S-class MB:s, with no meaningful NVH discomfort.

The whole idea is to put "Flying" into the Spur, by this upgrade, mildly modified custom alignment and carefully selected OEM sized sticky tires like Michelin PS4S. It's obvious that it won't rival much lighter sports cars but it'll be a much better match to my driving style and preferences. More grip, predictability and dialing out some of the understeer is in order.

Oh well, back to the drawing board. Time to prepare a full casting job and/or turning bushings from PU bar stock in a lathe if there's no off-the-shelf solution.

 

I'm not really worried about possible fatigue effects. I haven't come across any even after 100k miles on poly bushes so the risk seems rather minor and most street-spec PU bushes still dampen vibrations pretty well, even though they won't flex and give as much as rubber. I've driven a couple of brand new CGT/Spurs hence have an idea how a well-kept and serviced example should feel, but while it's pretty good it's still not quite there yet.

Then again, most owners don't really DRIVE their cars, the sales associate sitting on the passenger seat was a bit pale after a couple of miles of twisties at maybe 8 or 9/10ths. The Bentley Power on Ice -event was quite a bit better, even though the attendees obviously didn't represent typical Bentley owner (or enthusiast) demographics. It's a few years since I had a chance to attend but it was a nice eye-opener how competent these cars can be on snow and ice too, perfect all-rounders for the climate we have around here.