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Discussion Starter · #1 · (Edited)
Gents,
I can reveal that, at least for my car, there was a surprisingly simple solution for the hopeless tramlining: 15mm rear spacers, one at each side.

My car during the test had:
OEM 18/19" combo
OEM Pirelli AR
AW intermediate spacers(but now uprated to race for more camber)
1mm toe in on each side
I have not tried car without AW spacers, had them installed before I picked up the car. Even with these, tramlining was close to intolerable.

After installation, nothing else changed, it was more or less gone, by that I mean it was feeling like a normal sports car, tendency, but far from intolerable. On top of that, I did not notice downsides at trackday, possibly better handling, something that surprised me. So for now, no downsides, and I have been running it for 3-4000km. I also have fellow 4C owner with 17/18" who did it, and it was better, but difference maybe not as huge as mine.

Have thought long and hard why, not that it matters since result is good, but my hypothesis is:
Outside of rear rubber is now approx 10mm outside front. This mean that front used to be 10mm outside. On a uneven road, this will cause front wheels to start climbing before rear, and by that steering will be self amplifying.

But this should be tested by more owners before we can say that it's a general fix.

EDIT:
I tested and ran mostly of the 3-4000km with Pirelli AR (OEM) tires.
Recently I changed to Michelin Pilot Sport 4, hoped for a further improvement. Actually I did not notice a big improvement in tramlining, but they are better and more comfortable.
 

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That's an interesting result.

The problem with things like a "general fix," is that while some have "hopeless tramlining" (even after attempting the most common fixes...blocks & toe in), others (me) have no tramlining with pure stock cars. And yes, we have plenty of "English B road" types of roads.

Still, glad you resolved your problem. I hope it helps others. Worth a try for those who are frustrated.

P.S. When I say no tramlining, I'm not talking about roads with truck ruts where any car would tramline. I'm talking about randomly bumpy roads, where I feel the bumps in the steering wheel, but the car is not moving all over the road.
 

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Discussion Starter · #3 ·
Thanks, would be great if it could solve the problem for others.

It would be interesting regarding hypothesis if you bothered measuring the distance from outer edge of wheels and compare front and rear. I simply measured with a measuring tape and aimed along the wheel with a camera, then zoomed to see the number. So very poor accuracy, I would expect ±5mm, but nevertheless an indication. My result was:
Front: 1847mm
Rear: 1869mm

Whatever that is in inches and fractions.....:p
 

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I did those measurements some time ago. Actually, outer edges of tire treads. I agree with your ~10 mm wider at the front per side with 205s/235s.

For reference, official track spec (measured at center of tread) is F 1,639 mm, R 1,604 mm.
 

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Discussion Starter · #6 ·
I did those measurements some time ago. Actually, outer edges of tire treads. I agree with your ~10 mm wider at the front per side with 205s/235s.

For reference, official track spec (measured at center of tread) is F 1,639 mm, R 1,604 mm.
Thanks, then at least this is not the whole problem. Spacers will effectively make rear suspension softer as well due to wheel forces being further from spring/damper fastening point. I do have sport suspension, do you?
 

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No sport suspension. 18/19 wheels.

I expect you will notice further improvement after wearing a few mm off the new tires. Also, it's mentioned all the time, but worth repeating, ensure correct tire pressures.
 

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Discussion Starter · #9 ·
No sport suspension. 18/19 wheels.

I expect you will notice further improvement after wearing a few mm off the new tires. Also, it's mentioned all the time, but worth repeating, ensure correct tire pressures.
That's notoriously monitored. I have always have a digital gauge in the car, since I do not trust the manometers at service stations. Slightly anal, yes.... In short, I'm quite sure that I have done what I can regarding things similar to this, feel that I have done my homework properly - and then some.

OK, so you have a softer rear suspension. Could be a part of the solution maybe....
 

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Discussion Starter · #10 ·
Subscribed untill somebody else tries and confirms.

Sent from my F8332 using Tapatalk
See if you can borrow a pair if you have a friend with spacer on all 4 wheels.

I bought 4, then in a strike of luck I decided to try with only two mounted. So, I handed the two remaining ones over to my friend, and asked him to test. He lives some hours drive from me, and told me on the phone "there is a difference. You're not getting them back". But as mentioned, I do not think the difference is as big as mine, since I have the larger wheels, and his car was not too bad in the first place, after AW spacers install(Bad before that).

Note1: You have to remove the small bolt holding the brake disc, at least on my spacers.
Note2: My friend experienced some vibration, so be very thorough when mounting them.
 

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Well, adding just rear spacers is consistent with things one can do to mitigate tramlining.

If you popped in here and said you added all four or just fronts, and it got better, I'd have a headache.

I have tramlining only on roads where there are two well-worn ruts from years of cars wearing down the road, and some of these roads are highways/freeways where no one would call them B roads. It's mild rut, road crown, mild rut spanning the road config that demands two hands.

Most B roads and back roads, as we call them in my area, are off camber for drainage, but I don't get any tramlining. The basic camber settings in the stock race suspension shrug off the negative camber on any B roads I've been on.
.
 
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Ah, mine is still not great.

Have Jamie's intermediate blocks and have @jamiesalfa rear spacers (20mm).

Car still moves about and needs fighting consantly on most roads. Can't go in the outside lane of localy dual carriageways.
 

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Discussion Starter · #13 ·
@jamiesalfa rear spacers (20mm).
AW wheel spacers, right? But then my description is of course subjective. It still handles like a sports car, with the normal downsides of that. So its very far from a "flying carpet".

Have you tried without spacers, if it becomes worse?
 

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Ah, mine is still not great.

Have Jamie's intermediate blocks and have @jamiesalfa rear spacers (20mm).

Car still moves about and needs fighting consantly on most roads. Can't go in the outside lane of localy dual carriageways.
What are your alignment settings front and rear? Ditch the rear spacers and see what happens. I assume you added these to fill out the wheel wells (ie for aesthetics) rather than for any application of handling theory.
You should have zero toe or slight toe-in at the front and toe-in at the rear. I’m using my iPad with specs on my laptop, though I’ve posted that I use Rudi Gales’ Road settings elsewhere. I haven’t eliminated tramlining but it’s reduced without the need for blocks.
 

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Discussion Starter · #15 ·
What are your alignment settings front and rear? Ditch the rear spacers and see what happens. I assume you added these to fill out the wheel wells (ie for aesthetics) rather than for any application of handling theory.
Well, to be honest, I did. I'm very skeptic to spacers, but rear was so far in, so I thought what the heck, handling cannot get much worse, so I bought 20mm for all 4 wheels as suggested on the site, "to not alter behavior".

And yes, I have had alignment check. Three times, in fact.... Only thing that was off, was a slightly low front camber. This is now increased, and under steer out of corner is much, much better.
 

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Well, to be honest, I did. I'm very skeptic to spacers, but rear was so far in, so I thought what the heck, handling cannot get much worse, so I bought 20mm for all 4 wheels as suggested on the site, "to not alter behavior".

And yes, I have had alignment check. Three times, in fact.... Only thing that was off, was a slightly low front camber. This is now increased, and under steer out of corner is much, much better.
What values did your alignment shop use? Data needed.
 

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What are your alignment settings front and rear? Ditch the rear spacers and see what happens. I assume you added these to fill out the wheel wells (ie for aesthetics) rather than for any application of handling theory.
You should have zero toe or slight toe-in at the front and toe-in at the rear. I’m using my iPad with specs on my laptop, though I’ve posted that I use Rudi Gales’ Road settings elsewhere. I haven’t eliminated tramlining but it’s reduced without the need for blocks.
What values have you got ??

My invited coilovers will arrive next month so I’m keen to set my car up to lose my tram line


Sent from my iPhone using Tapatalk
 

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What values have you got ??

My invited coilovers will arrive next month so I’m keen to set my car up to lose my tram line


Sent from my iPhone using Tapatalk
First of all change tyres to Michelin Pilot Super sports. You’re running the18/19” wheel stagger so no problem there. The Pirellis seem to exacerbate the tramlining effect. I’ve used Rudi Gales’ Street Specs. No idea of the castor specs but have added a bit more negative camber (now -1.7 deg each side) at the front to counter understeer while going to zero toe instead of toe-out. Less tramlining but not eliminated. I’m currently on Hankook R-S4 rubber 215/45x17 front, 235/40x18 rear. My front tyres seem to be wearing more evenly now too.
It’s very important that specs both sides are exactly the same. Some here seem to have accepted alignment specs that differ slightly left and right. Not good. Our cars are very sensitive to spec changes. I’ve also got uniball bushes that tighten up the rear so standard rear toe-in (40’ each side) might be better for stability without these. Specs posted below..
 

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That's an interesting result.

The problem with things like a "general fix," is that while some have "hopeless tramlining" (even after attempting the most common fixes...blocks & toe in), others (me) have no tramlining with pure stock cars. And yes, we have plenty of "English B road" types of roads.

Still, glad you resolved your problem. I hope it helps others. Worth a try for those who are frustrated.

P.S. When I say no tramlining, I'm not talking about roads with truck ruts where any car would tramline. I'm talking about randomly bumpy roads, where I feel the bumps in the steering wheel, but the car is not moving all over the road.
Who tried toe in and the car still tramlines?
 
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