Wheel Alignment

[bchapman]

I had the dealer put the car up on the rack to check the wheel alignment since I too have been wearing out the insides of the front tires, with 20,000+ on them.

The tech said my car was "in spec", but on the high side of the tolerance. He changed the left front camber from -1.2 to -0.5 and the right side from -0.9 to -0.6. The caster was changed from 5.5 (L) and 5.6 (R) to 5.3(L) and 5.9 (R). Toe was modified from -0.07(L) and -0.09 (R) to -0.05(L) and -0.06 (R).

The tech has had a couple of other Marauders with the same odd tire wear. His opinion now is that it's the BFGoodrich tires. I don't know if I believe that. I've had soft tires (Toyo) on my '97 T-Bird and never experienced uneven wear.

The car's steering is straight but feels somewhat looser. We'll see what happens with the wear pattern now.

[MMM2003]

Same problem here with 23k miles on it and wear on inside. I had mine rotated/switched left to right and right to left at 16k miles.

I'm waiting till October for snow tire setup, to get an alignment done. Heard to many bad stories about wheels being scratched when they do an alignment with the stock wheels.

I'm planning on the Tetsu (winter tire) setup. Next summer (2k4) I'll need a new set of BFG's as well.
Has anyone found different brand "stock size" replacement tires ?

[Thomas C Potter]

BCH, I suspect with -1/2 camber you'll be much better. I would have recommended to go with -1/4 camber. I would blame the camber and not the BFG's.

TP

[bchapman]

MMM, just make sure they have that adapter for the Marauder. The dealer didn't have one last week and had to order one.

TP, I remember seeing your post about the camber reduction. That info was helpful when I was at the shop today. Thanks.

Any ideas on why the rear center tread is wearing? Tire inflation is at 32.

[Thomas C Potter]

BCH, too much air pressure. The load rating on that 245/55 is much higher than the MM rear requires. I'd suggest 26-28 psi to help even out wear. My 1968 XL (4000 lb car) has had 255/60/15 in rear for years and I use 24-26 to even wear out.

TP

[TripleTransAm]

I've never been a fan of uneven alignment specs, road crown or not. If I'm on the left lane of the highway and it wants to pull left, I'll pull a bit to the right to keep the car straight, vice versa for the right lane. Some old-timer alignment guy tried to set my GTA up like that twice, offset to handle road crown, and both times it drove me nuts to the point where I had to force him to set it up like I wanted it (neutral).

The "looseness" you're feeling is the decrease in caster, most likely. I'm a big fan of lots of positive caster myself, it results in a heavier steering but much more stability (if you have trouble turning the wheels, so will road imperfections!). The car will track straighter with more positive caster. As for negative camber, I prefer a smidgeon of negative, just enough to say I'm preloading the suspension but not enough to wear out bearings and insides of tires.

And as for toe... well, the idea of having tires pointing in opposing directions screams lost power and efficiency to me. Not to mention added tire wear.

I'll be getting my alignment checked shortly, and I'll be asking for maximum caster, about -0.2 or slightly more negative camber, and 0 toe. And I won't be offsetting the values... left = right.

[russ in VA]

I just rolled 10k miles and the inside front tread blocks on both fronts are smooth. As soon as I get a chance, I'll be rolling into the dealer and raising heck to see if I can get some free tires. I'll have them check the alignment (if they have the right tool to protect the wheels), but I doubt it is out of spec as the car tracks straight and true. Of course I'll try for new rears too since the centers are wearing back there too, but I'm not as upset or expectant of replacements since after noticing the premature wear at about 5k (and hearing simillar complaints here) I dropped the rears to 27psi and they seem to be wearing evenly across the tread now. The added benifit to having more pressure up front than in the rear is the car turns in better and handles more neutrally (less understeer).

As others have said, an excess of negative camber will wear the inside of the tire more rapidly (but it also helps the car handle well which I am not willing to give up) ... but the kind of rounding I'm seeing on my car is too extreem to be due to camber and is limited to just the inside tread block ... typically negative camber will cause a gradually worn tire across the tread from the inside to at least the middle of the tire. The kind of inside edge only wear I am seeing would normally be due to excess toe out. But here is the rub ... toe out should cause the car to pull when tracking down the road especially if there are any ruts in the road or grooves. As mentioned in a post above, lots of caster helps keep the steering centered but it is toe IN that will keep it going straight .... and since my car tracks well and is not "all over the road" I expect to find the toe is near zero or slightly in.

So basically I've said that I believe my radical inside tire wear is not due to too much negative camber OR to too much toe out so that begs the question what DO I believe is responsable .... I drive THE HE-double-toothpicks out of the car that's what!

Take 2 tons of vehicle, equip it with grippy tires and put a corner junky behind the wheel and tire wear happens. I put perfomance tires on all my cars and I generally dont get more than 20k miles out of ANY tire so I surely don't expect to on a beast like the MM. You want perfomance handling you have to pay the price. It's a coralary (sp) to the old adage "speed costs money, how fast do you want to go?" I would be happy to get 15k to 20k miles out of the tires.

I do expect them to wear EVENLY though, and that is what concerns me. We need to find out why the inside edge is the first to go. Based on the fact that my tires have worn out sooner than most others (no surprise to me), I think it must be something that is brought into play more when driving the car hard. The rest of the tread looks to have about half it's life left but I have worn the edges off more quickly. This also leads to me discounting the thought that excess negative-camber or toe-out is the culprit since both of those contribute to the vehicles abilty to corner but cause tire wear when going straight. My driving style caused acellerated tire wear in corners, not going down the interstate, but I have the same wear characteristics that everyone is experiencing just faster.

I'm no suspension engineer, but I do have a theory. The accelerated inside edge wear could be do to an excess of "ackerman". Put simply, ackerman steering means that the inside front tire turns more than the outer tire (essentially there is more toe out when turning). This is necessary for both tires to track through the corner without scrubbing. If you don't have enough ackerman, the inside tire is essentially toed in while cornering and the outside treadblock of that tire can wear since it is being forced to scrub through the turn. If you have too much (as I suspect) then the inside tread block scrubs and wears prematurely. Look at www.auto-ware.com/setup/ack_rac.htm for a better explaination of this. The benefit of too much ackerman is that it can help the car turn if it has a tendancy to push. This may be the case on our big heavy cars and Ford may have dialed up the ackerman to try and offset it. If the steering geometry on our MM's is the same as on the pedestrian GM's and CV's, then I bet this is our culprit. Those cars have narrower tires (225/60/16's I believe) and more importantly the tires are much harder PLUS the cars are typically not cornered as hard as an MM is likely to be SO an excess of ackerman could have helped their handing without exhibiting excess tire wear. If they carried this over to our cars with a stiffer suspension and stickier tires it could cause our inside edges to wear. I believe that our steering geometry and alignment specs should be tuned differently than theirs ... question is are they? Any ford insider have an answer? Some input from a hard core suspesion techy on my theory would be helpful. I know we have at least one formula car driver on the board and EVERYTHING is adjustable on those cars and must be tuned just right to get a fast lap ... any input from those in the know?

[russ in VA]

I just thought of something. How is the tire wear on the CV sport or for that matter on any CV that has been equipped with performance tires and driven hard by an enthusiast owner?

You guys have any input?

Of course I just remembered that the entire line got new front suspension for 2003. That says to me that anything or CV bretheren can tell us may not apply to our cars unless they have 2003 or newer CV's.

Anyone?

[bchapman]

I'm going to bring the vehicle back in. The steering just doesn't feel tight enough and as Steve said, I had hit some uneven road on the way back yesterday and the car just about wanted to run away with me. I'm feeling uneasy about increasing the tire life at the price of decreasing the handling ability. I don't drive too aggressively but I need that car to respond instantly and with instinctive road feel.

I'm going to ask them to put the caster back in and leave the other settings the way they are. I appreciate all the input and hopefully we can all figure out what's going on with the front end. Ford engineers won't be aware of the problem unless we bring it to their attention. 1-800-392-FORD.

[TripleTransAm]

Interesting comments about the Ackerman. I'm curious about CV and GM tire wear as well, this may be a good lead. Thanks for the good description.

[gdmjoe]

Originally posted by russ in VA
I just thought of something. How is the tire wear on the CV sport or for that matter on any CV that has been equipped with performance tires and driven hard by an enthusiast owner?

You guys have any input?

Of course I just remembered that the entire line got new front suspension for 2003. That says to me that anything or CV bretheren can tell us may not apply to our cars unless they have 2003 or newer CV's.

Anyone?

Have experience with a 2000 CV LX HPP ( 36K miles when traded in on a ), 2003 CV LX Sport ( current ride with 12K miles ).

Both were / are driven aggressively a lot, though no track time. And while the Goodyear Eagle LS ( standard on both ) may not qualify as a true high performance tire, they are more than adequite ( IMO ).

Neither of the cars experienced the tire wear that's been noted; at 36K the 2000 had well over 50% thread, and the 2003 shows a slight reduction in thread depth. In both cases, however, the wear was even across the tire width.

Having some experience with a warmed-over 1986 Mustang GT with 225 / 50 X 16 and 245 / 45 X 16 Gatorbacks, I would suspect chamber as well; Ford likes to set the front-end alignment on their performance cars so that they corner real well. Since the Mustang was primarily a straight-line driver, I had the alignment shop give the "normal" flavor. *Sure saved on tire co$t$.

FWIT

[Warpath]

Originally posted by TripleTransAm
...I'm a big fan of lots of positive caster myself, it results in a heavier steering but much more stability (if you have trouble turning the wheels, so will road imperfections!). The car will track straighter with more positive caster. As for negative camber, I prefer a smidgeon of negative, just enough to say I'm preloading the suspension but not enough to wear out bearings and insides of tires.

And as for toe... well, the idea of having tires pointing in opposing directions screams lost power and efficiency to me. Not to mention added tire wear.

I'll be getting my alignment checked shortly, and I'll be asking for maximum caster, about -0.2 or slightly more negative camber, and 0 toe. And I won't be offsetting the values... left = right.

Higher caster does make it track better. But, it also will make it more sensitive to road crown and grooves in the road. You may find it pulling much more down the crown or move with grooves in the road.

I prefer about -0.5 deg camber. You want negative camber because when you corner, the outside wheel camber will numerically increase (closer to 0 - closer to perpendicular to the road) and will increase the tire contact patch. It will improve cornering. Guys who race sometimes go -1 deg and higher. That's too high for a street car however IMO.

Negative toe will give better on center feel and will be a bit slower off center turn. If you go to 0 or positive, it may get to the point where its darty. Sometimes it is set with positive toe so that as you go down the road, the rolling resistance of the tires, friction, etc. will reduce toe and improve tire wear. Its all personal opinion though. Everyone's tastes are different.

[TripleTransAm]

Originally posted by Warpath
Higher caster does make it track better. But, it also will make it more sensitive to road crown and grooves in the road. You may find it pulling much more down the crown or move with grooves in the road.


That's odd... I noticed the exact opposite with both my '87 and my '98, when I had them aligned to my own specs in 2000. My '87 uses the modified MacPherson setup, but the '98 uses a double unequal length control arm setup. Cranking up the caster really straightened the cars out on grooved or rutted pavement.

I'm not discrediting your info, there must be some other variable in there that's resulting in our divergent opinions... *shrug*

[Warpath]

What I stated is typical. A Mustang (which is McPherson also)owner once upped caster a lot stated that the car actually "hunted" for grooves in the road. Suspension type and geometry, tires, and a lot of other parameters determine how much caster you should have. You 87 and 98 simply put may not have had enough and when you upped it, you were still OK. I imagine if you increased it even more, you would see what I am talking about.

[fastcar]

As others have said, an excess of negative camber will wear the inside of the tire more rapidly (but it also helps the car handle well which I am not willing to give up) ... but the kind of rounding I'm seeing on my car is too extreem to be due to camber and is limited to just the inside tread block ... typically negative camber will cause a gradually worn tire across the tread from the inside to at least the middle of the tire. The kind of inside edge only wear I am seeing would normally be due to excess toe out.

When I picked up my Marauder in Georgia, I glanced at the tires, and thought they looked great. I ran her against the rev limiter a lot on the way back to Boston and it wasn't until I got home that I saw BELTS SHOWING on the inside. OMG, I'm so glad I didn't have a blow out at 120!

Then I found this problem on many other threads. I guess I joined the club...

I see that many folks have gotten better mileage by increasing tire pressure, bring Camber down to 0, and Toe to 0.

But I have to agree with the above quote, the wear on these tires is ABNORMAL. You SHOULD be able to run 1-3 degrees negative camber on a car, and you will get inside wear, yes, but NOT ON JUST THE FIRST 1-1/2 OF THE TIRE!

My tires look like someone chucked them in a lath, and beveled the edge at a 45 degree angle. THAT IS SERIOUSLY MESSED UP.:bs:

WE SHOULD be able to run some negative and get a gradual wear pattern starting on the outside, running to the inside. My tires look brand new the whole way across, accept for that last 1-1/2.

I think something is SERIOUSLY SCREWED UP WITH OUR SUSPENSION GEOMETRY. I've driven Panthers since 1986, and NONE of the recirculating ball cars (pre-2003) EVER did ANYTHING like this.

Did anyone ever get to the bottom of this? Does anyone know why these cars with innocuous alignment settings show UFO wear patterns???

I also noticed this car pushes more than my P71s did.

fastcar:shake:

[RaceLegend79]

Well I dont know how it is on the alignment computers by your house but if you align the tires at a shop here and most others they should have the udated specs that eliminate this wear problem but if you want check their specs against the specs that are here on the site you should just have to search "alignment spec" and I dont remeber which one it was but it was either the 2nd or 3rd thread down that had the specs but if you cant find them just pm me and Ill send them to you. I would now but theyre put away in my car and its late.

[fastcar]

Hi RaceLegend79,

Thanks for you kind offer. I have the specs everyone is using, my question is why these cars have FREAKY tire wear with specs that are not very unusual. Even unusual specs would typically produce USUAL wear patterns.

This inside edge only, carved down to the belts is CRAZY and denotes to me a fundamental issue with DESIGN. I thought I was getting an upgrade when I went from the old platform to the new...

fastcar:mad2:

[Stranger in the Black Sedan]

Fastcar, you are totally correct that we should be able to run a lot more than the low-performance 0 camber 0 toe alignments that everyone is setting their cars up with around here, without beveling the edge of the tire down to the cords. Something is messed up with the aluminum cradle front end on these cars.

[fastblackmerc]

Here are the "preferred" Marauder alignment specs. Wore out my first set of fronts at 15K, next set with these specs have more than 25K on them and they still look good.

Carfixer's Alignment Specs

A friend of mine needed these today, so I thought I'd post up the alignment specs for reference.

The inside edge wear of the front tires is caused by 2 things: negative camber and negative toe (toe out). Caster is not a tire wearing angle. The outside edge wear can be caused by excessive toe in and aggressive cornering.

Factory camber spec is -.5 degrees or- .75 degrees
Factory toe spec is -.15 degrees or- .20 degrees
(BTW, this info came from their website which is updated periodically and may differ from previously published material, such as CD's and paper manuals)
That means your alignment could have -1.25 degrees of camber and toe out of -.35 degrees and still be in the green. This will wipe out the inside edges in 20K miles IMO.

All of the MM's I've aligned (about 10) had at least -1.0 degrees of camber and always toe out of -.10 degrees or more from the factory. That's why almost all MM's you see have excessive inside edge tire wear.

For best tire wear, here is what I use on all MM alignments:
Camber: -.3 to -.5 degrees.
Toe: Zero degrees.
Caster: 5-6.5 degrees positive with .3 degree lead on the right side.

*Camber can affect cornering feel. The more negative camber you have, the better it will handle corners. Most drivers will never feel the difference, especially on the street.

[Stranger in the Black Sedan]

Yeah see though, zero toe is not going to be optimal for steering feel. Having some toe in/out loads the tie rod ends to take the slack out. Toe in will make the car track straighter, since the steering will want to return to center, and toe out will make the steering quicker entering a corner. My marauder with zero toe definitely is less straight-line stable than it was with the factory alignment.

It is pretty standard for modern passenger cars to have more than -0.5 degree camber and nonzero toe without unusual tire wear. We might as well put bias ply tires on this car if it has to be set up with no alignment angles.

[fastcar]

Thanks for the specs, FastBlackMerc,

As stated two posts up, I have the specs, its the fact that you have to use low-po specs to get normal wear pattern that is fishy. It's irritating.

EvilBrother, I think you said it. When I looked under the car today at the alignment shop and saw that big aluminum cradle under the front end, I immediately had a gut feeling that it was the culprit...

My car was checked today. It had -1 degree of Camber, and -.25 total toe out. The tow out is a bit high, but not enough to explain the ridiculous wear pattern on my tires. One degree of negative camber on any front end, should not annihilate the first 1 inch of the inside tread block, and leave the rest pristine! If we had good geometry front ends, this would NOT be an issue.

The tech will MAX out the Caster, put -1/2 degree on it, and +1/16 toe in on it. I will run 45 lbs, and probably not have this happen.

The question and mystery remains, has anyone gotten to the bottom of this, and figured out what makes these front ends so retarded?

fastcar:burnout:

[sailsmen]

I got 40K on mine and yes it was the inside edge.

40K is plenty good enough for me. The front end is set up to minimize plowing/understeer.

It's the trade off for a performance vehicle.

[Stranger in the Black Sedan]

fastcar, it's going to be nearly impossible to get an answer to your question. Most people on this board think the Marauder is "too perfect" to have (gasp) some compromised design aspects. My car with negative 0.75 camber and 0.15 deg toe out beveled the edge off the tire too, and the rest of the tire had more than 50% left. Just the nature of this genuine Ford vehicle.

The camber and toe curves are probably to blame, as the front suspension moves. Although the specs look normal at ride height, they probably do some weird stuff under compression, to try to keep this heavy tank on the road.

Trust me it annoys me too, to be able to run less camber on this car than grampa's buick is spec'd at.

[fastcar]

Even those that would admit to a serious engineering issue would be hard pressed to come up with any explanations. I think your synopsis is probably accurate. It probably does some strange stuff during wheel travel. The tires look like they must ride at a 45 degree angle to the pavement on the inside edge! It's too weird.

I JUST GOT MY 300A BACK FROM THE SHOP TODAY. It had -1.0 camber, 5.5 caster, and .25" toe-out.
He set it up with -.5 camber, 6 (max) caster, and .1" toe-IN, plus 42 lbs pressure. I'll post how they wear over the rest of summer and fall...

STEERING EFFORT is much more. The car was dying to turn before, now you have to tell it to. BUT, it steers beautifully, no complaints, and is very nice esp. on the highway.

I hung some INSANE off ramps. TIRE PRESSURE REALLY IMPROVES THE HANDLING OF THESE CARS, IT'S NUTS! It's like a 4200lb go-kart.

fastcar:burnout:

[fastcar]

I said I'd follow up about the tires.

I put about 20,000 miles on two new stock front tires, and they still look great. I mean, still nearly new looking. I swear I could put another 20k on them. THERE IS NO EVIDENCE OF INSIDE WEAR.

I'm not happy with the car's handling at the limit with these specs. It's neutral to push in a corner. I like a little oversteer.

I'm going with Goodyear F1's, 255/45/18s on the front and rear, so the added meat might help the front stick better.

Since the old tires fared so well with the -.5/6.0/.1" in, I'm going to go a little more on the next alignment: -.75/6.0/.1" out. I'm hoping to improve turn in, and get some oversteer on this thing.

The car will be lowered 1", and the ass end lowered more, so that should help as well.

I'll let you know how it goes. I also heard I need to slot my control arms when cutting the coils, so I'll give the technician this instruction as well.

fastcar :burnout:

[Mr. Man]

I've heard the factory set-up is very aggressive and that the car fixer specs really help get more miles out of your tires. Some mechanics won't do the fix as they get numbers that fall w/in Ford specs. Trust the car fixer specs you won't be disappointed.

[Stranger in the Black Sedan]

See the above. the carfixer specs improve tire wear but make the car steer more like an old people machine. The factory negative camber and toe out made the car have quicker turn-in and better cornering but at the expense of tire wear

[fastcar]

See the above. the carfixer specs improve tire wear but make the car steer more like an old people machine. The factory negative camber and toe out made the car have quicker turn-in and better cornering but at the expense of tire wear

+1

fastcar:burnout: