My car ('11 Mustang) tramlines like mad. On some roads, I have the wheel cocked about an inch to the left to go straight. If there are a lot of ruts in the road, such as during road construction or coming up to a stoplight on a road compressed heavily with ruts from semi trucks, the steering wheel sometimes feels like it's being wrenched from my hand.
I know having different caster between the two sides helps prevent tramlining. What else can cause this? Toe? Camber?
I'm taking the car in for an alignment on Wednesday afternoon. The fellow at the shop already told me I can specify my own alignment settings instead of the factory ones. So what should I do to have a good compromise on handling for autocross and not being somewhat unsafe on the highway?
A difference side to side in caster will allow the car to go straight on a raked road if everything else is in line. It will also effect straight line stability. But tramlining is probably more a result of tires, a toe out condition or bump steer. Is your car lowered? Do you have wider or stickier tires on it than stock?
The stock tire width is 235; I have 255s on it for street use. The tramlining seems to have gotten worse as the tires have worn. I have slightly uneven wear on the front tires (the outsides are worn more than the insides). Could that be causing it? Should I try swapping tires from front to back?
In reply to Sky_Render:
Is the outside wear even or saw toothed?
The wider tires will contribute to tramlining, but that may or may not be the only source of the problem.
The outside wear is very even. I've had those tires for over a year, and I noticed that it got worse as the autocross season went on last year and the tires wore out more. I thought my alignment was getting out of spec, but now I wonder if it's just from the uneven wear.
Toe out can cause tramlining
I have toe-in, unless hard autocross cornering made my toe shift some.
You are gonna want to E36-can the stock alignment. The outside wear your talking about is from autocrossing, pure and simple.
Needs more negative camber.
You are going to want to check the toe settings.
My knowledge base is either general or SN-95 centered, but tramlining is something my mustang has been fighting all through its development.
Being that you are seeking a compromise between autocross performance and daily use it gets interesting. You are (obviously) be somewhere between the factory setup and the hot setup that others are running. If you can get the alignment numbers that someone like Terry Fair or Strano is using and dail them down closer to factory you will find your ideal. (at least thats my bet)
The factory alignment was never designed with autocross in mind. Your wear indicates that you need more camber. Toe you are going to be between factory toe-in setting and neutral (zero). Camber, your probably going to be hunting for 2 to 2.5 depending on just how much street vs autocross. These are shooting from the hip guesses, but give you an idea the direction your going to need to move in.
Sky_Render wrote:
The outside wear is very even. I've had those tires for over a year, and I noticed that it got worse as the autocross season went on last year and the tires wore out more. I thought my alignment was getting out of spec, but now I wonder if it's just from the uneven wear.
You're going to have more outside wear if you are using these tires for autocrossing and aren't rotating them frequently. You may also have some contribution from not having enough negative camber or too much positive camber. Too much toe in will cause outside wear, but it will have a saw tooth pattern to it, not smooth.
Factory camber was around -0.7. I was running -1.6 and still had more wear on the outsides. I'm dialing that up to -1.8 or -2.0.
Would keeping my toe pointed in help in this department, or should I go to zero toe?
Apexcarver:
How much tramlining do you feel is acceptable? Sometimes, I've got my wheel cocked about an inch to the left to go straight, depending on the types of roads.
I didnt worry as much in steady state, I care more about coming up on a rutted road and having to fight the car to track straight. Not that I ever drove my mustang on it, but how is yours doing over the leftovers of that construction on I-270 south of Frederick? My car would have felt like it wanted to zigzag right off the road. My other cars get jerked around a bit by it, but not pucker-factor jerked.
Side question, you still running stock front bushings? I know you played with your rear suspension a lot, what all has been changed on the front?
I'm using stock front bushings except for the polybushings on the front sway bar. Interestingly, I started noticing the tramlining immediately after installing the sway bars.
EDIT: And I guess I'm not too worried about steady-state, as long as my car isn't broken. What I don't want is something seriously wrong with it that is getting worse. I'm still wondering if the uneven tire wear is causing it.
It can be very dependant on the tires.
Stiffer front bushings (LCA) would cut down on it some.
I would bet that the alignment and new tires will help a ton though.
bravenrace wrote:
In reply to Sky_Render:
Is the outside wear even or saw toothed?
The wider tires will contribute to tramlining, but that may or may not be the only source of the problem.
Wide low profile tires with stiff sidewalls are prone to tramline.
This is probably something you've already looked at, but are all the bushings still in good shape? If they're worn out and allowing the control arm to move around, that could be contributing to your tramlining. What about the tie rod ends? These shouldn't be bad on a 2 year old car, but if you've done a lot of autocrossing, it could be an issue.
I'll double check the bushings, but they looked OK to me last time I was under there. The tires are not any lower profile than the factory rubber, and I never really noticed it tramlining much until towards the end of the season. It REALLY started doing it after my very last autocross of last year, when I did a lot of glorious powerslides and general hooning. So I'm thinking/hoping tire wear might have something to do with it.
Well, that would explain it. I had toe-out on my right wheel and toe-in on the left, which would definitely cause a car to pull towards the right. The fellows that own the alignment shop race cars themselves and sponsor a few teams at the local dirt track, so they were quite familiar with customers wanting custom specs.
In reply to Sky_Render:
Front wheels? If so, that just means he didn't have the wheels straight when he measured it. Toe is really one measurement, not two. IOW, if you have 1/8" out on one side and 1/4" in on the other, you have 1/8" toe in, because that's what you'll have if you point one wheel straight ahead. I know nowadays they like to tell you left and right, and they measure toe in degrees, but the fact is that when you drive down the road you don't have one side toed out and one toed in, they average, so it's really just one measurement. Total toe out can make it tramline, and a really severe amount of toe in may cause that, but without real numbers you can't say.
If the wheel is level and you have toe out on one side and toe in on the other, the vehicle would turn to one side while the wheel is level. That's what my car was doing. In other words, the adjustment on the front tie rods made the "neutral" or "straight" position of the steering wheel to be cocked to the left.
If you were having a steady state problem, that explains it.
My mustang tramlines, but steady state is no problem whatsoever. Over road irregularities it became a bit unstable and wanted to change lanes on its own (abruptly).
Is it driving better?
Sky_Render wrote:
If the wheel is level and you have toe out on one side and toe in on the other, the vehicle would turn to one side while the wheel is level. That's what my car was doing. In other words, the adjustment on the front tie rods made the "neutral" or "straight" position of the steering wheel to be cocked to the left.
It doesn't work that way. Caster makes the wheels self center.
Further explanation:
http://www.mojo-tyres.com/desktopdefault.aspx/tabid-36/50_read-60/
Cheapest fix would be to put a nice set of 205/75 15 whitewalls on it. She'll cruise like a dream.
Fat tires and agressive camber settings make a car want to change direction quickly on a track. Why would it stop doing that on a freeway?
bravenrace wrote:
Sky_Render wrote:
If the wheel is level and you have toe out on one side and toe in on the other, the vehicle would turn to one side while the wheel is level. That's what my car was doing. In other words, the adjustment on the front tie rods made the "neutral" or "straight" position of the steering wheel to be cocked to the left.
It doesn't work that way. Caster makes the wheels self center.
Further explanation:
http://www.mojo-tyres.com/desktopdefault.aspx/tabid-36/50_read-60/
I don't think you understand what I'm saying. In order to get the car to go straight on a level surface (steady state), the wheel had to be turned to the left. This was because the wheels were "turned" to the right when the steering wheel was centered.
Apexcarver wrote:
If you were having a steady state problem, that explains it.
My mustang tramlines, but steady state is no problem whatsoever. Over road irregularities it became a bit unstable and wanted to change lanes on its own (abruptly).
Is it driving better?
Yes, it's driving much better now. It still tramlines somewhat, but I haven't rotated the tires yet. The camber and caster were also uneven between the two sides.
bravenrace wrote:
In reply to Sky_Render:
Front wheels? If so, that just means he didn't have the wheels straight when he measured it. Toe is really one measurement, not two. IOW, if you have 1/8" out on one side and 1/4" in on the other, you have 1/8" toe in, because that's what you'll have if you point one wheel straight ahead. I know nowadays they like to tell you left and right, and they measure toe in degrees, but the fact is that when you drive down the road you don't have one side toed out and one toed in, they average, so it's really just one measurement. Total toe out can make it tramline, and a really severe amount of toe in may cause that, but without real numbers you can't say.
Exactly, the wheels are solidly connected by the linkage.
