Tramlining

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Discussion

7db

Original Poster:

6,058 posts

236 months

Tuesday 19th August 2008
quotequote all
Ok - it's not going away. Changed tyres and now I've gone from the smoothest most lovely poised set-up ever to a mad tramlining beast whose inclinations to jump at oncoming traffic I can just about overcome. The wiggle on crossing white lines is incredible for such a thin layer of paint, but you can feel both grip changes on and off the line.

Is the price you pay for stickier tyres feeling the true horror of what the road is really doing?

I've checked tyre pressures (18-19 cold all round), and alignment (seems straight, and was tested in garage). The springs are aching to be played with, but I'm not sure if that is the next answer. Any thoughts?

StressedDave

841 posts

268 months

Tuesday 19th August 2008
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Alignment? Go and see Mr Bones at wheels-inmotion and see what his magical machine says. Farting around with spring rates is not going to change something which is effectively tyre and alignment related.

anonymous-user

60 months

Tuesday 19th August 2008
quotequote all
7db said:
Changed tyres and now I've gone from the smoothest most lovely poised set-up ever to a mad tramlining beast whose inclinations to jump at oncoming traffic I can just about overcome. The wiggle on crossing white lines is incredible for such a thin layer of paint, but you can feel both grip changes on and off the line.

Is the price you pay for stickier tyres feeling the true horror of what the road is really doing?
Strange, I had exactly the opposite. When I first bought my car both front tyres were barely legal and it tramlined like a bugger. As soon as I stuck a fresh set of Avons on it, all was well.

205lad

310 posts

201 months

Tuesday 19th August 2008
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Presuming here you changed brand/type of tyre.

I've had cars that worked well on one brand (Goodyear F1s) but suffered terribly from tramlining on another perfectly acceptable brand (Michelin Pilots). In fact it went far beyond that- behaviour on the Pilots was unpredictable in the wet. It was suggested to me that it could be a faulty batch of tyres once the geometry had been checked. I didn't take the risk and switched back to Goodyears.

stefan1

978 posts

238 months

Tuesday 19th August 2008
quotequote all
7db said:
Ok - it's not going away. Changed tyres and now I've gone from the smoothest most lovely poised set-up ever to a mad tramlining beast whose inclinations to jump at oncoming traffic I can just about overcome. The wiggle on crossing white lines is incredible for such a thin layer of paint, but you can feel both grip changes on and off the line.

Is the price you pay for stickier tyres feeling the true horror of what the road is really doing?

I've checked tyre pressures (18-19 cold all round), and alignment (seems straight, and was tested in garage). The springs are aching to be played with, but I'm not sure if that is the next answer. Any thoughts?
No solutions I am afraid - can only say that the CSR I drive (which I know has different suspension but has a similar track to your SV I would assume) does not suffer this issue. I'm running Avon R500s, with pressures of 24 / 23 psi front /rear. It tracks very straight and true, as your's used to.

Are your tyres stickier than the R500s?

I can only agree with Dave - it may be worth getting the alignment re-checked somewhere else on a full 4-wheel alignment jig. Might even be worth getting the car corner weighted.

Kind regards

Steve

7db

Original Poster:

6,058 posts

236 months

Tuesday 19th August 2008
quotequote all
The new ones are 48Rs, the old ones were 539s. How much is a trip to Mr Bones going to set me back?

StressedDave

841 posts

268 months

Tuesday 19th August 2008
quotequote all
About 100 GBP or so... He should be able to do pull down testing as well by now so he can see if something nasty happens when the suspension is further loaded.

p1esk

4,914 posts

202 months

Tuesday 19th August 2008
quotequote all
If people drove sensible cars(1) they wouldn't have all this hassle. smile

(1) Like a nice Pug. 406 HDi. hehe

But seriously, I hope you get it sorted out without too much bother, Dave. It will of course be frustrating when you thought you were making improvements.

Best wishes all,
Dave.

944Nick

1,005 posts

220 months

Tuesday 19th August 2008
quotequote all
Dave

Is the 18-19 psi the recommended pressure or one you arrived at by trial and error for the previous tyres? If trial and error, you could perhaps try the recommended settings and see if that makes any difference.

regards
Nick

7db

Original Poster:

6,058 posts

236 months

Tuesday 19th August 2008
quotequote all
I got those pressures from other Club members who suggested them as a starting point. They seem to produce even wear (mid vs edge) at that sort of level.

I think higher pressures promote tramlining - have I got that right?

StressedDave

841 posts

268 months

Thursday 21st August 2008
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They'll certainly give more response to a sidewall load, so in general yes. Have you checked the state of your bushes (front and rear). IIRC the de Dion bush is particularly prone to wear and doesn't give a nice feel to the car when it is worn.

DJ_AS

352 posts

213 months

Thursday 21st August 2008
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Do your new tyres have a different tread pattern to the old? My Mondeo was following the camber of the road a bit much so took it to Tony Bones at WIM for a check up. Geometry was near on perfect so he swapped front and rear tyres (different makes and patterns).

Problem solved.

Swapped 'em back eventually and problem returned.

Tony Bones explained how certain tread patterns could cause tramlining etc (on top of things like presssure, compound, wear etc etc etc). Its all a bit of a black art.


7db

Original Poster:

6,058 posts

236 months

Thursday 21st August 2008
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StressedDave said:
Have you checked the state of your bushes (front and rear).
Is important to keep ones front bush trimmed by a professional?

BertBert

19,533 posts

217 months

Sunday 24th August 2008
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That's the classic problem of ACB10s, but unusual to show up in a change from 539s to 048s. Have you got anyone handy with spare wheels on (say) CR500s to see what happens?

I also had a problem where putting ACB10s on showed up a front suspension issue. That was a worn rh lower swivel. It was fine on CR500s but on ACBs, the car shot right on acceleration.

Are you running the front slightly toe'd out? That's a common (hack) cure used on caterhams to counter understeer (no slight intended). That might be fine on one tyre/tread pattern, but be horrid on another?

Has the ride height (or rake) changed at all with the new tyres and changed the bump-steer characteristics?

Do you know what the front geo is set to? Could the change of tyres coincide with another change (pot-hole screwing up the tracking)?

(clutching at straws) Bert


dreamer75

1,402 posts

234 months

Monday 25th August 2008
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DB I've got a set of wheels with 500's on which if you ask really nicely you might bea ble to try on the road - they're my race tyres though so no track trashing!!

7db

Original Poster:

6,058 posts

236 months

Monday 25th August 2008
quotequote all
Would they be around on Saturday? We can see how they feel on the hill route... smile

i'll need to do something when I'm waiting for my starter to work again...

dreamer75

1,402 posts

234 months

Thursday 28th August 2008
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Don't think I can fit them in the scoob I'm afraid!