Has any got Powerflex bushes on their XJR?
Discussion
bmthnick1981 said:
How does one go about doing this Norman? Is it something my mechanic should know about?
We fit Powerflex bushes to a number of XKs and the suspension settings do not need to be adjusted. This has been confirmed by the technical department at Powerflex. What Norman has not said is that his needed adjusting as he has had other suspension work carried out on his car, including adjustable shocks, which did mean that his settings needed to be adjusted.For a normal suspension set up, having Poly bushes fitted does not require any adjustment.
Soraya
Zippyworld said:
Just seeking confirmation, as this thread started on the XJR, is the information from Powerflex regarding the XK applicable to the XJ too then ?
Yes the same for all cars. As the Powerflex bushes are size for size replacements so no adjustment needed. We are authorised dealers in Powerflex bushes and confirmed this with their tecnical department.As I said in a previous post Norman has had other suspension work carried out on his car including lowering and Spires adjustable coil over shocks fitted. In his case it would require the suspension geometry to be reset.
S
It's got nothing to do with my other suspension mod's
Polly bushes have different physical characteristics to the standard rubber bushes
This has to be compensated for in the suspension set up
You can't say with one breath that polly's give a more controlled suspension movement
Then in the next breath that you don't have to make any compensations regarding Toe in/out Etc
And to do the job properly, don't forget the Camber
The local tyre centre can't adjust that so will ignore that side of things
Polly bushes have different physical characteristics to the standard rubber bushes
This has to be compensated for in the suspension set up
You can't say with one breath that polly's give a more controlled suspension movement
Then in the next breath that you don't have to make any compensations regarding Toe in/out Etc
And to do the job properly, don't forget the Camber
The local tyre centre can't adjust that so will ignore that side of things
Edited by NormanD on Monday 18th April 15:34
NormanD said:
It's got nothing to do with my other suspension mod's
Polly bushes have different physical characteristics to the standard rubber bushes
This has to be compensated for in the suspension set up
You can't say with one breath that polly's give a more controlled suspension movement
Then in the next breath that you don't have to make any compensations regarding Toe in/out Etc
And to do the job properly, don't forget the Camber
The local tyre centre can't adjust that so will ignore that side of things
Norman I agree that after any suspension work has been done the geometry of the should checked to ensure it is within Jaguar Manufacturers tollerances. No adjustment to the Jaguar geometry is needed. Polly bushes have different physical characteristics to the standard rubber bushes
This has to be compensated for in the suspension set up
You can't say with one breath that polly's give a more controlled suspension movement
Then in the next breath that you don't have to make any compensations regarding Toe in/out Etc
And to do the job properly, don't forget the Camber
The local tyre centre can't adjust that so will ignore that side of things
Edited by NormanD on Monday 18th April 15:34
Again I will point out that you had specific suspension work done that did require an adjustment outside of the Jaguar normal paramaters.
Obviously I would be more prepared to believe the information supplied by the manufacturer of the product than someone who has only had the bushes fitted to their car.
Ooooow a little bit testy at designXKR then ?
I will be taking my car to be aligned with a reputable expert in the Cheshire area and I will see what they have to say. I may be wasting my money then again maybe not but will post out what they say.
My car has had no work on the suspension at present.
I will be taking my car to be aligned with a reputable expert in the Cheshire area and I will see what they have to say. I may be wasting my money then again maybe not but will post out what they say.
My car has had no work on the suspension at present.
I'd be reluctant to believe that no changes need to be made. If I may quote a paragraph taken from Grassroots Motorsports magazine and reproduced here (my highlights):
"The amount of toe-in or toe-out dialed into a given car is dependent on the compliance of the suspension and the desired handling characteristics. To improve ride quality, street cars are equipped with relatively soft rubber bushings at their suspension links, and thus the links move a fair amount when they are loaded. Race cars, in contrast, are fitted with steel spherical bearings or very hard urethane, metal or plastic bushings to provide optimum rigidity and control of suspension links. Thus, a street car requires a greater static toe-in than does a race car, so as to avoid the condition wherein bushing compliance allows the wheels to assume a toe-out condition."
A misspent youth poring over Allan Staniforth's well known book on car suspension would lead me to a similar logical conclusion, and that similarly caster and camber would also be affected.
Whilst stationary, polybushes will probably not put the suspension settings outside of Jaguar's stated limits, but on the move Jags aren't known for their light weight or low power outputs, so the reduced deflection in suspension components is going to be felt far more than on most other cars. Clearly, if you only potter about in the Jag you'd likely be ok, but then if you were going to do that why would you fit polybushes anyway?
If you fail to dial out some of the inherent toe-in (since the dynamic forces acting on the suspension aren't going to toe-out the wheels to the same degree), you'll find the car less willing to respond to changes in direction and potentially experience an increase in tyre wear and frictional losses as the tyres scrub their way across the road even in a straight line.
I'm no polybush expert, so if someone can provide a counter argument I'll happily stand corrected.
"The amount of toe-in or toe-out dialed into a given car is dependent on the compliance of the suspension and the desired handling characteristics. To improve ride quality, street cars are equipped with relatively soft rubber bushings at their suspension links, and thus the links move a fair amount when they are loaded. Race cars, in contrast, are fitted with steel spherical bearings or very hard urethane, metal or plastic bushings to provide optimum rigidity and control of suspension links. Thus, a street car requires a greater static toe-in than does a race car, so as to avoid the condition wherein bushing compliance allows the wheels to assume a toe-out condition."
A misspent youth poring over Allan Staniforth's well known book on car suspension would lead me to a similar logical conclusion, and that similarly caster and camber would also be affected.
Whilst stationary, polybushes will probably not put the suspension settings outside of Jaguar's stated limits, but on the move Jags aren't known for their light weight or low power outputs, so the reduced deflection in suspension components is going to be felt far more than on most other cars. Clearly, if you only potter about in the Jag you'd likely be ok, but then if you were going to do that why would you fit polybushes anyway?
If you fail to dial out some of the inherent toe-in (since the dynamic forces acting on the suspension aren't going to toe-out the wheels to the same degree), you'll find the car less willing to respond to changes in direction and potentially experience an increase in tyre wear and frictional losses as the tyres scrub their way across the road even in a straight line.
I'm no polybush expert, so if someone can provide a counter argument I'll happily stand corrected.
They aren't worth their weight in lead. You'll not be able to hear the better half if you install them. Please send me your paypal adress and cost for shipping stateside and I'll take them off your hand.
What it was worth a try LOL. They will be a little noiser, firmer and will require some antisqueak lube every so often but I'll be going that route as mine wear out a bit more.
What it was worth a try LOL. They will be a little noiser, firmer and will require some antisqueak lube every so often but I'll be going that route as mine wear out a bit more.
benebob said:
They aren't worth their weight in lead. You'll not be able to hear the better half if you install them. Please send me your paypal adress and cost for shipping stateside and I'll take them off your hand.
What it was worth a try LOL. They will be a little noiser, firmer and will require some antisqueak lube every so often but I'll be going that route as mine wear out a bit more.
I've actually decided i'm not going to bother getting them fitted. The existing ones seem fine, I was only considering it as they came with the car.What it was worth a try LOL. They will be a little noiser, firmer and will require some antisqueak lube every so often but I'll be going that route as mine wear out a bit more.
PM me if you (or anyone) else would be interested in buying them for a reasonable price.
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