Tramlining problem. Car keeps trying to kill me.

[destrux]

Still not happy with the steering in my car. I've determined that what my car is doing is probably not related to any worn suspension parts, or the fact that I've lowered the car, or the steering damper being removed. I think it's a classic case of tramlining. I can hold the steering wheel perfectly straight, and the car will follow grooves/ruts in the road in a rather violent manner. All the highways around here are grooved terribly and need to be repaved. The car feels much better on smooth roads, but that's no consolation when I can't keep it in my lane on every other road.

From what I read on the tire rack website about tramlining, it's probably the tires. For those of you that don't have this problem with your car, what kind of tire (and tire size) are you running?

Right now I have 255/40-17 Ecsta LE Sport on all 4 corners. Running them at 30 psi. Lower pressure are supposed to help with this problem, but I don't want to run lower than 30 because the tires heat evenly at 30.

 

[Koenigturbo]

stop drinking.......Lol"""

 

[fixitman04]

caster needs to be adjusted more towards the positive.

 

[destrux]

I'm going to try extra caster. I have it at the max OE spec right now. I'm also going to try to set it to the max OE toe in, right now it's near zero toe.

I never touch the sauce, lol.

 

[hvyman]

Wider tires up front will track more with the road. I've ran both 255 and 265 up front and they both do it here and there. But roads around here are nice so it's not much of a problem.

 

[Dan_Gyoba]

Probably going with 225 width front tires would help most. That extra 30mm picks up a lot of rut...

 

[Supracentral]

I run 245/45's up front and 275/40's in the rear and I don't have much of a problem. I'm lowered and run:

• Front:
  • Camber – 1.0 degrees
  • Caster + 5.0 degrees
  • Toe 0.00 mm

• Rear:
  • Camber -1.5 degrees
  • Toe in (total) 1.00 mm

I do run R-compound tires however so they are super sticky when warm and like driving on hockey pucks when cold.

Edit: Shit, sorry, just realized this is a MKIII post - specs above are for a MKIV.

 

[Poodles]

Well, removing the steering stabilizer might be the issue. The later cars without it ran different pulleys on the power steering pump. The point is, more pressure in the system to take the place of the dampener. IJ had more info on this...

 

[IJ.]

I always cranked in a bunch of caster in mine

 

[destrux]

I have a 1JZ, so it's a 92-95' pump. I wouldn't want my more assist, the steering is over assisted feeling already. I'd love to swap to a PPS rack, but I don't know whats involved with that swap or if it would even fit the 87'.

I guess I'm back to finding a steering damper to try though, because it does make sense that without it there it will make the effect of uneven pavement more apparent.

I think I'm going to get 235's or maybe 245's on the front too. I hate to compromise grip for the sake of comfort, but the car is just no fun to drive like this. I'll do that after I try the damper and new alignment, I'd rather not let new tires sit on the car over the winter and get hardened up.

 

[IJ.]

I ran 265's on the front of mine, while it would follow the camber of the road it didn't tramline.

 

[destrux]

I did the alignment to factory spec, with caster on the high side of the range. I had it way out last time from some experimenting. Camber was -0.6 degrees, and caster was at 9 degrees, toe was zero. I also centered the tie rods, because the rack was off center by about 10mm, which I didn't think much of before but I notice the factory spec is only 1.5mm.

When I was done I was checking my fluids and found my power steering fluid had some metal flake in it. So I extracted the fluid from the reservoir and pulled the magnetic filter I put in the return line. It had some sand sized flakes of steel, maybe a pile the size of a pencil eraser. I think these may have come from the power steering pump since it's been making a slight whining noise ever since I put the JDM engine in that it came with. I'm worried they are affecting the spool valve in the steering rack, maybe partially clogging it. My rack has 1/4" of steering wheel play before it offers any power assist or moves the wheels at all. I checked it out very carefully and the play is definitely in the spool valve. The steering rack on my mazda has zero movement before the spool valve reacts, so there might be a problem there. I just need to find time to pull the rack out and take it apart to see if it's fixable or if I need a new one.

After the alignment the car feels a little better, but still not right.

Thanks IJ, if you can avoid it with 265's I should be ok with keeping my 255's.

Oh, if anyone cares... my alignment sheet...

 

[destrux]

You all were right, it was the tire width.

I swapped to stock wheels with some 205/55R16 all season tires for the winter in case I need to move the car in the snow. The car drives great now.

I found something interesting though, the tires I'm using (the 255 summer tires) have 2 ply lyocell sidewalls rather than the usual polyester material. Kumho says they're stiffer than 2 ply polyester sidewalls. They feel softer to me (softer turn in feel), but if they are stiffer maybe that's contributing to the problem.

I have a set of 215/45R17 Kumho Ecsta XS tires sitting here, I was going to try those but I'm not sure if I want to go that skinny. They run wider than usual 215's though, they are actually just as wide as some goodyear 235's I just took off another car, they have an 8" tread width and require no stretching to fit my wheels since the beads sit 9" apart with the tire dismounted. Hmm.

 

[adampecush]

not that it will help that much with tramlining, but dial a little more camber into that front suspension. unless you're doing all of your driving on the highway, you are losing handling performance at -0.6 degrees.

 

[destrux]

I know I am, but the amount of grip this car has already is beyond what I can push it to on the street. If I ever improve my abilities to the point where I need more grip, or if I do some track days, I'll experiment and add some as needed.

 

[IJ.]

I always ran a bit more caster in my Mk3, made it more stable/predictable at high speeds, slight downside was heavier steering at low speeds/parking but it's might help the tramlining thing.

 

[te72]

Destrux, I suspect you deal with the same real world problem I have: Crappy roads.

Do you have these problems on freshly paved, or otherwise smooth roads? My car only ever seemed to have this issue on the well traveled roads that host the majority of the semi-truck traffic, with the ruts worn into the roads. When your tires are almost as wide as theirs...

 

[taka21]

ok so how do you dial in more caster without affecting the camber ????

 

[destrux]

Yeah I'm running 8.0 degrees caster now, it did help. Still a bit hairy, but tolerable. I plan to mess with some steering rack mods in the spring.. play around with spool valve changes.

Taka21, changing caster without changing camber... that doesn't require anything out of the ordinary. The stock adjusters are set up to do that.