Nervous Rear End
Discussion
Hey folks, just after a bit of advice...again
Having just switched from stock 15/16 Imola wheels with new T1R tyres to a set of SP12's (17/18's) with recommended tyre fitments for the chim (215/40/17 fronts, and 245/35/18 rears) , I have noticed the rear of the car feels very loose at anything above 50 mph (seems to move about with the wind, but changing direction is fast and responsive).
I actually pulled over thinking there was a flat or a loose wheel
But all ok! 
The rest of the time the car handles brilliantly, very responsive and great grip levels.
I have checked the tyre pressures and am running 24psi front and rear and all are in great condition. Dunlop SP Sport Max's on the front, and Conti Sport Contact 3 on the rear, all with loads of tread.
Would the larger wheels show up a suspension issue, or is it simply that the car needs to have the suspension re-aligned with the different wheels fitted?
The car was originally set up with aftermarket 16/17in wheels when I bought the car, so I wouldn't have thought it would have made that much of a difference.
Ride is stock with standard dampers and springs.
Pics below
Any help hugely appreciated as always
Having just switched from stock 15/16 Imola wheels with new T1R tyres to a set of SP12's (17/18's) with recommended tyre fitments for the chim (215/40/17 fronts, and 245/35/18 rears) , I have noticed the rear of the car feels very loose at anything above 50 mph (seems to move about with the wind, but changing direction is fast and responsive).
I actually pulled over thinking there was a flat or a loose wheel
But all ok! The rest of the time the car handles brilliantly, very responsive and great grip levels.
I have checked the tyre pressures and am running 24psi front and rear and all are in great condition. Dunlop SP Sport Max's on the front, and Conti Sport Contact 3 on the rear, all with loads of tread.
Would the larger wheels show up a suspension issue, or is it simply that the car needs to have the suspension re-aligned with the different wheels fitted?
The car was originally set up with aftermarket 16/17in wheels when I bought the car, so I wouldn't have thought it would have made that much of a difference.
Ride is stock with standard dampers and springs.
Pics below
Any help hugely appreciated as always
When I first got my car it was a killing machine.....and the target was me!!
It had had the ball joints changed for the pre-sale MOT and not re-aligned, and the alignment was way out.
One Hunter machine 4-wheel alignment and Tiddles gave me a brilliant and safe ride home.
So, have you had yours properly aligned? TVRs are very sensitive to wheel alignment.
It had had the ball joints changed for the pre-sale MOT and not re-aligned, and the alignment was way out.
One Hunter machine 4-wheel alignment and Tiddles gave me a brilliant and safe ride home.
So, have you had yours properly aligned? TVRs are very sensitive to wheel alignment.
I have given this some thought and have a possible explanation...
Assuming you now have lower profile tyres on the new bigger diameter wheels than you did on the previous set you will accordingly have less side wall, and therefore (assumption here) less sidewall movement. It would certainly be a substantial difference from the original 16" rears.... So.. Any side force (such as wind) acting upon the car would be more directly transmitted to the contact patch between tyre and road rather than some of it being absorbed by flex in the tyre sidewall...
Try running with a couple of psi less in the rears...
Other possible influences might be:
Wheel offset - can widen or narrow the track
Wheel/tyre width - more or less contact with the road than you had before...
A combination of all the above is pretty likely to give a different 'feel'
Whilst, assuming other things being equal (like track not changed - which affected beastie quite a bit when I put 16's on the front) the change in diameter shouldn't affect the geo (I don't think), however if your geo wasn't spot on to begin with it's entirely possible that any or all of the above factors might make any geo misalignments much more noticeable.
Anyway, that's my two penneth
Chilli
Assuming you now have lower profile tyres on the new bigger diameter wheels than you did on the previous set you will accordingly have less side wall, and therefore (assumption here) less sidewall movement. It would certainly be a substantial difference from the original 16" rears.... So.. Any side force (such as wind) acting upon the car would be more directly transmitted to the contact patch between tyre and road rather than some of it being absorbed by flex in the tyre sidewall...
Try running with a couple of psi less in the rears...
Other possible influences might be:
Wheel offset - can widen or narrow the track
Wheel/tyre width - more or less contact with the road than you had before...
A combination of all the above is pretty likely to give a different 'feel'
Whilst, assuming other things being equal (like track not changed - which affected beastie quite a bit when I put 16's on the front) the change in diameter shouldn't affect the geo (I don't think), however if your geo wasn't spot on to begin with it's entirely possible that any or all of the above factors might make any geo misalignments much more noticeable.
Anyway, that's my two penneth
Chilli
s
Nice car but get those wheels and rubber band profile tyres off it and go back to standard wheels & tyres.
At the turn of the century a very clever Frenchman discovered if you filled a rubber wheel with air you got a wonderful ride, since the 90's boy racers have been reducing the volume of air by fitting bigger & bigger wheels with lower & lower profile tyres.
The result is always the same, horible ride quality & tramlining for little or no handling improvement.
The pneumatic tyre was a brilliant invention and is the most important component in your suspension, go back to standard wheels & tyre profiles and all your troubles will be gone.
Just look at an F1 car, plenty of air in their tyres and face ripping extreme corning g-forces too!
At the turn of the century a very clever Frenchman discovered if you filled a rubber wheel with air you got a wonderful ride, since the 90's boy racers have been reducing the volume of air by fitting bigger & bigger wheels with lower & lower profile tyres.
The result is always the same, horible ride quality & tramlining for little or no handling improvement.
The pneumatic tyre was a brilliant invention and is the most important component in your suspension, go back to standard wheels & tyre profiles and all your troubles will be gone.
Just look at an F1 car, plenty of air in their tyres and face ripping extreme corning g-forces too!
Edited by ChimpOnGas on Wednesday 15th April 07:54
s p a c e m a n said:
ChilliWhizz said:
He's running Conti Sport Contact 3's on the rear though....
I should refrain from posting when the little hand on the clock is pointing at 4 
Going completely off topic for a mo (apologies to the OP). s p a c e m a n, I see you had an S4 B5 Avant, I'm seriously thinking of chopping my old Golf VR6 in for one of these (the daily hack, trips to the dump, winter trips etc), Seems you may be qualified to comment on the choice? would appreciate any advice on this, please pm me if you can advise.. much thanks in advance, Chilli
ChimpOnGas said:
Nice car but get those wheels and rubber band profile tyres off it and go back to standard wheels & tyres.
At the turn of the century a very clever Frenchman discovered if you filled a rubber wheel with air you got a wonderful ride, since the 90's boy racers have been reducing the volume of air by fitting bigger & bigger wheels with lower & lower profile tyres.
The result is always the same, horible ride quality & tramlining for little or no handling improvement.
The pneumatic tyre was a brilliant invention and is the most important component in your suspension, go back to standard wheels & tyre profiles and all your troubles will be gone.
Just look at an F1 car, plenty of air in their tyres and face ripping extreme corning g-forces too!
Couldn't agree more.At the turn of the century a very clever Frenchman discovered if you filled a rubber wheel with air you got a wonderful ride, since the 90's boy racers have been reducing the volume of air by fitting bigger & bigger wheels with lower & lower profile tyres.
The result is always the same, horible ride quality & tramlining for little or no handling improvement.
The pneumatic tyre was a brilliant invention and is the most important component in your suspension, go back to standard wheels & tyre profiles and all your troubles will be gone.
Just look at an F1 car, plenty of air in their tyres and face ripping extreme corning g-forces too!
Folk forget these cars are designed/set up to run what were large tyre combinations of the day and altering the dynamics of the cars with modern wheel/tyre combinations without at least attempting to alter the geometry is bound to have an effect.
Also the tyres are more suited to a 2+ ton Euro barge rather than a sportscar.
V8 GRF said:
Couldn't agree more.
Folk forget these cars are designed/set up to run what were large tyre combinations of the day and altering the dynamics of the cars with modern wheel/tyre combinations without at least attempting to alter the geometry is bound to have an effect.
Also the tyres are more suited to a 2+ ton Euro barge rather than a sportscar.
And having a reasonable height side-wall provides some level of protection from our pock-marked roads!Folk forget these cars are designed/set up to run what were large tyre combinations of the day and altering the dynamics of the cars with modern wheel/tyre combinations without at least attempting to alter the geometry is bound to have an effect.
Also the tyres are more suited to a 2+ ton Euro barge rather than a sportscar.
Thanks for the reply's guy's. Definitely food for thought.
The strange thing is, the ride quality is spot on even with the lower profile tyres (I was worried that it would be a lot harsher), and the cornering is far more responsive. Which I expected due to the lower profile.
The only issue is the vagueness at speed (not even high speed as it happens at 50mph upwards.
It definitely felt like the wind was upsetting the balance, and moving the rear about.
I do understand regarding the higher sidewalls, but would have thought this would give more flex and feel slightly less planted, but with a harsher ride trade off.
Crossing over lines etc that you would normally expect to cause tramlining, have no effect, as with sharp camber changes. The car runs true over all of these
Maybe it is just a matter of getting the car re-tracked and go from there.
Still have the original wheels at the moment, but really keen to keep these.
The strange thing is, the ride quality is spot on even with the lower profile tyres (I was worried that it would be a lot harsher), and the cornering is far more responsive. Which I expected due to the lower profile.
The only issue is the vagueness at speed (not even high speed as it happens at 50mph upwards.
It definitely felt like the wind was upsetting the balance, and moving the rear about.
I do understand regarding the higher sidewalls, but would have thought this would give more flex and feel slightly less planted, but with a harsher ride trade off.
Crossing over lines etc that you would normally expect to cause tramlining, have no effect, as with sharp camber changes. The car runs true over all of these
Maybe it is just a matter of getting the car re-tracked and go from there.
Still have the original wheels at the moment, but really keen to keep these.
SILICONEKID345HP said:
Someone as sprayed some blue over the rear end of your car .. just noticed also front near side .Hope you catch them 
That is a very nice car
LOL, amazing what can happen to your car when left unattended.That is a very nice car
Edited by SILICONEKID345HP on Monday 13th April 22:17
Soon to be Viper GTR blue......I think
thanks mate
Edited by PJ57 on Wednesday 15th April 11:49
QBee said:
When I first got my car it was a killing machine.....and the target was me!!
It had had the ball joints changed for the pre-sale MOT and not re-aligned, and the alignment was way out.
One Hunter machine 4-wheel alignment and Tiddles gave me a brilliant and safe ride home.
So, have you had yours properly aligned? TVRs are very sensitive to wheel alignment.
Thanks, think this is the next move. Going to get it in the air and re-check bearings etc first (had no problems before), and get it booked in for a full set-upIt had had the ball joints changed for the pre-sale MOT and not re-aligned, and the alignment was way out.
One Hunter machine 4-wheel alignment and Tiddles gave me a brilliant and safe ride home.
So, have you had yours properly aligned? TVRs are very sensitive to wheel alignment.
ChimpOnGas said:
Nice car but get those wheels and rubber band profile tyres off it and go back to standard wheels & tyres.
At the turn of the century a very clever Frenchman discovered if you filled a rubber wheel with air you got a wonderful ride, since the 90's boy racers have been reducing the volume of air by fitting bigger & bigger wheels with lower & lower profile tyres.
The result is always the same, horible ride quality & tramlining for little or no handling improvement.
The pneumatic tyre was a brilliant invention and is the most important component in your suspension, go back to standard wheels & tyre profiles and all your troubles will be gone.
Just look at an F1 car, plenty of air in their tyres and face ripping extreme corning g-forces too!
Thanks for your thoughts, At the turn of the century a very clever Frenchman discovered if you filled a rubber wheel with air you got a wonderful ride, since the 90's boy racers have been reducing the volume of air by fitting bigger & bigger wheels with lower & lower profile tyres.
The result is always the same, horible ride quality & tramlining for little or no handling improvement.
The pneumatic tyre was a brilliant invention and is the most important component in your suspension, go back to standard wheels & tyre profiles and all your troubles will be gone.
Just look at an F1 car, plenty of air in their tyres and face ripping extreme corning g-forces too!
Edited by ChimpOnGas on Wednesday 15th April 07:54
The chim did have larger wheels on when I bought it, 16" fronts and 17" on the rear, but were fox racing brand with all the wrong offsets, although the car drove really well.
I went back to stock wheels with the idea of getting the front end converted to stock Mk3 lights when the car is re-sprayed later in the year.
Unfortunately, as with all best laid plans, the amount of work with wing reconstruction etc, was going to cost a fortune, so I am left with a fairly aftermarket looking car.
With the chim needing to stay at stock ride height, I felt the standard wheels looked a little lost on a non standard car and the SP12's fill the arched better. Hence the decision to return to bigger, better fitting wheels.
I love the stock wheel/body look, with subtle lowering to take away some of the arch gap, but being South London/Surrey based, I have the curse of the speed humps everywhere, and have owned many cars that are a real PITA each time I come across one. Have to almost stop, drive over diagonally and wait to hear the sound of something scraping
The beauty on my chim, is in nearly 5000 miles, is hasn't scraped on a single hump or bump.....Quite proud of that
I do get the F1 debate too, I understand the tyres actually provide most of the damping vs the super stiff suspension.
On the flip side though, if you look at all the touring/rally & V8 supercars etc that are running far less down force, and in reality closer to the chim, they are all running far lower profile tyres than F1 and most road cars.
I certainly expected a certain amount of tramlining with the wider tyres, and a slightly harsher ride, yet with the current setup and tyre pressures, neither are present.
Just this strange loose rear end feel......That kinda sounds all wrong
The front feels great, and very planted in comparison.
Edited by PJ57 on Wednesday 15th April 11:55
Edited by PJ57 on Wednesday 15th April 11:58
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