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| Uneven Front Tire Wear; Front tires wearing out on the inside | |
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| Topic Started: Feb 6 2010, 08:16 PM (276 Views) | |
| kawmanse | Feb 6 2010, 08:16 PM Post #1 |
New Member
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I bought my first Metro, a 1991 3-Cyl, 5 spd, a year and a half ago. I replaced all the tires and now, after about 10,000 miles I noticed the front tires were wearing out unevenly with the inside portion going first.  I had also replaced both axles. Could I have put something together incorrectly or could it just be a bad alignment? Any ideas? Thanks. |
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| jrdbarnhart | Feb 6 2010, 10:04 PM Post #2 |
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did you have the alignment checked when you got the tires? |
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| Woodie | Feb 6 2010, 10:11 PM Post #3 |
 
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Did you get it aligned after you replaced the axles? Any time you loosen a bolt on the knuckle it might not be the same when you put it back together. Also, look for bad control arm bushings, ball joints, or struts. Might just be the toe in/out adjustment. |
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| kawmanse | Feb 6 2010, 11:09 PM Post #4 |
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New Member
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Thanks for the feedback. I have to admit that I didn't get it aligned after putting in the axles. It seemed to track just fine. I'll have to take it in and have it done. |
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| Bad Bent | Feb 7 2010, 12:47 AM Post #5 |
Facetious Educated Donkey
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You can check out DIY Toe In Adjustment if you'd like to check it yourself. You may/should have trustworthy & skilled tire alignment shops where you live. 
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| irishman72 | Feb 8 2010, 06:42 PM Post #6 |
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Fresh Fish
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I had similar issues before, and since I just replaced my steering knuckle, figure it's time to check the alignment. Just wanted to ask, though, should there be *any* toe-in at all? Or should the tires run truly parallel? Thanks. |
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| Bad Bent | Feb 9 2010, 12:47 AM Post #7 |
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Facetious Educated Donkey
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Here is a nice article explaining wheel alignment Tire Tech Information It says "The toe setting is typically used to help compensate for the suspension bushings compliance to enhance tire wear." and "Conversely, a front-wheel drive vehicle "pulls" the vehicle through the front axle, resulting in forward movement of the suspension arms against their bushings. Therefore most front-wheel drive vehicles use some negative toe-out to compensate for the movement, again enabling the tires to run parallel to each other at speed." Italics added. It was at http://ecomodder.com/ that I read about 0o toe in for better mpg.  My '91s service manual says Toe is Front 0 +/- 2 mm (.078 in) and Rear 2 +/- 2 mm. So 1/16"=.0625 and 5/64" is .078125. Got a Stanley tape measure? The smallest increments are 1/32", count 3 of them and go back 1/2. Incidentally the human eye is accurate to 1/2 the increment on a scale. Edit:  mwebb reminded me... 0o toe in for less roll resistance and better mpg. I changed the wheel bearings also.
Edited by Bad Bent, Feb 9 2010, 02:34 AM.
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| mwebb | Feb 9 2010, 01:09 AM Post #8 |
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to minimize rolling resistance and maintain stability i set my front toe to zero and set rear toe to 50% of specification |
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| kawmanse | Feb 9 2010, 09:21 PM Post #9 |
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New Member
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OK, here's the latest - I went out to the car and did the string thing around all four tires to check the alignment and found it to be very close to 0 degrees all the way around - certainly there was not enough tow-out to cause that level of tire wear. Then I got to looking at the caster/camber and noted the bottom of both front tires sticking out from the car noticeably, which would cause the tire wear I'm seeing. Then I thought about when I installed the new front axles - could they be too long causing the tires to stick out on the bottom? Could I have messed up when I installed the axles not getting them far enough into the tranny? How much of a gap should there be between the transmission and the large part of the inner axle? Any thoughts out there? It was my first time installing axles. I could have screwed something up. Thanks everyone for the help! |
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| mwebb | Feb 10 2010, 01:02 AM Post #10 |
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it would be very near impossible to measure toe with a string maybe a steel ruler 2 or three times , after rolling the car a little and take the average as the wheel tire combination has significant run out , enough so that when you set up an alignment machine you need to calibrate the machine to account for the run out for each wheel every time jack up you car in the rear and spin a rear wheel , look at it as it spins from the rear .... you will see what i mean your car is toed out or castor is fraked on one side the castor value should be within .5 degrees from side to side OR that can cause tire wear , but it is not common usually if castor is different side to side , the car has clocked a curb or pothole and the suspension is bent back ward s a little bit if castor is off , toe can be set correctly and still , you will wear the tires . even if present , negative camber usually does not wear out tires unless it is extreme a good alignment shop will provide a printout of before and after values , most newer equipment has printer s - just ask the people in the shop. the ball joint and lower control arm locate the outside limits of where the wheel can be not the axle , the inner CV joint of the drive axle has a considerable amount of in and out travel to allow for the suspension movement take it to a reputable alignment shop put away the string |
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| rmcelwee | Feb 10 2010, 02:04 AM Post #11 |
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The string made an INCREDIBLE difference in how my car drove. The wear corresponded to what the string was telling me. DIY alignment adjustments are commonplace in the racing community (although they also use seat of the pants and tire temps to tell them if they are on the right path). After being screwed over by every single alignment shop I have ever visited (all were reputable - just not reliable <G>) I decided to try it myself and was impressed with the results. |
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| redpepe | Feb 10 2010, 08:04 AM Post #12 |
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hi kawmanse, you've gotten good advice. however in my limited experience, the tire wear you show in your photos can be produced by the small changes in orientation that can occur in the fit of the knuckle to its mount bracket. while there could be other factors, since the wear is on the inside edge, one must suspect that the tires are leaning too far in at the top / out on the bottom. if one or the other of the front tires appears to be further out of vertical or wearing worse than the other, start with that one and try to reposition the knuckle by loosening the 2 bolts slightly and then prying in a correcting direction to bring them closer to vertical and then retightening. test drive ... it should not pull either way. if it does, try to similarly adjust the other wheel knuckle too. if there aren't major body deformations, you should be able to correct any wear and pull over time. your wear appears quite bad but the mileage these cars get on their tires is very good even if they wear unevenly .... i think i had some michelins that went 80k. rotating tires will help of course. |
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| cckelleyiii | Feb 10 2010, 09:48 AM Post #13 |
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New Member
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My experience with previous vehicles was that if all the alignment was correct and I had inside tire wear like this - front springs were weak and needed to be replaced. Each time I replaced front springs, got it aligned - no more problems. |
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| kawmanse | Feb 10 2010, 09:14 PM Post #14 |
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Thanks for all the responses so far. So I took it in for an alignment and here's what it shows: There were some adjustments to the tow-in/out but the caster/camber is still whacked. Could this have something to do with the axles? I'm at a loss here. |
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| carmech97 | Feb 10 2010, 09:50 PM Post #15 |
Backyard Mechanic
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Camber can be adjusted by replacing the bolts that fasten the bottom of the front struts to the steering knuckles with eccentric bolts which will allow the spindles to tilt up or down slightly when the position of the eccentric bolts are changed. If camber is out significantly, it will cause tire wear, albeit not as bad as incorrect toe would cause. The caster angle is what affects the steering return-ability of the vehicle, and the more positive caster is (the further the axle is tilted back), the faster the steering will return to center. Because caster only affects how far front or back the front axle is tilted, it will have no effect on tire scrub, and therefore not playing a role in tire wear. Unless, of course, your driving was entirely composed of circles with a radius of 10 feet.  Which clearly it is not. So don't worry about caster too much. The major tire wear angle is toe.
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