I had new tyres fitted a few years ago to my '87 740, and at the same time had the tracking (toe-in) set. The front tyres wore down on the outside edges far more than the rest of the tread, so I had the tracking rechecked at a different place. In the past year I have replace all the front suspension bushes and steering joints, including the bottom ball joints, track rods (tie rods to you US citizens) with the inner ball joint, and the outer, track rod end joints. I then had the tracking reset. Then I swapped the front tyres with the rear ones, which wear evenly. But after six months use, the outer edge - the first inch or so round the circumference - has again worn right down to near baldness on both fronts. Steering seems fine (though I've often thought this 740 steers like a whale compared to a 240) with no play, and no pull to one side, and no tendency to wander. The only thing left that I can think may cause this is that the camber is out of adjustment, but I think this can only be altered by replacing the stock suspension arms with ones of different lengths. Anyone think of anything else that may cause this, before I try and find someone with a rig that can check the camber? -- Stewart Hargrave For email, replace 'SpamOnlyToHere' with my name
As just said in another thread, different tires are different. Maybe these tires need a little more air. Assuming your "tracking" (we call it "toe" over here) is set correctly, and you're not driving around corners very fast all the time, and nothing in the suspension is bent or worn out then camber is all that's left. Camber can be adjusted by repositioning one of the studs in the top strut mount, the ones that pop up through the strut tower. Camber can be checked fairly easily with a plumb bob and tape measure, assuming your wheels are straight. Roll to a stop (no brakes) in the most level parking area you can find. Hang a plumb bob from the fender (wing to you), and measure the difference in distance from the top of the wheel to the bottom. This will let you know if you're in the ball park. On degree is 6.2mm on a 14" wheel, 6.7 mm on a 15" wheel. Assuming that you can find a level spot and are patient, you can be amazingly accurate. (It's a good idea to repeat your measurements while pointed in the other direction in the same spot to see if they are repeatable.) Note that any adjustments to camber will also change your toe, or tracking. -- Mike F. Thornhill (near Toronto), Ont. Replace tt with t (twice!) and remove parentheses to email me directly. (But I check the newsgroup more often than this email address.)
You've gotta stop driving down sewer pipes. The front tyres on most cars I have had wore that way to some extent (including the current 1980 volvo). With age I would expect it to develop toe out but that doesn't seem to stop wear on the outsides. At least I've saved quite a lot on alignments by practically never doing them - 99% of my tyre problems were caused by the tyres themselves.
It doesn't seem to be characteristic of under inflation. I would anticipate wear on both edges in this case. [..] Right, I'll find me tape measure. I had thought this was only possible on the 240; I thought the top of the suspension tower of the 740 was non-adjustable. I've just read Stephen Ringlee's well known 700/900 FAQ, which has details of re-drilling or slotting the tower bolt holes, which sounds like a practical idea. Thanks for the details. -- Stewart Hargrave For email, replace 'SpamOnlyToHere' with my name
Thinking about it, it may in fact be a function of the excellent steering lock these cars have. Manouvering into and out of tight parking spaces every day, even at dead slow speed, may scrub the outer edge of the tyre. Checking the alignment is usually a freebie around here, but as soon as they get the spanners out it's 30 quid. When I replaced the track (tie) rods I made a rudimentary jig to measured the length from knuckle to ball joint centre, and set the new ones to the same. To my satisfaction, it was within tolerance when it was checked. -- Stewart Hargrave For email, replace 'SpamOnlyToHere' with my name
The only other cause could be to do with the bushes on the front suspension arms. When they get worn they affect the tracking but only dynamically (car on move not stationary). Cheers, Peter.
What I mean by "different" is in the stiffness of the sidewall, or even the whole tire may allow it to "roll over" a little more during cornering than is optimum for the 740s particular suspension design. Adding a little extra air will support the tire a little better, keeping the wear more even. -- Mike F. Thornhill (near Toronto), Ont. Replace tt with t (twice!) and remove parentheses to email me directly. (But I check the newsgroup more often than this email address.)
Could be, but I suspect it's just the pressure on the outer front wheel round corners, especially its outer perimeter right at the fulcrum. I have no experience with other volvos but my 1980 wagon really handles like a pig round corners but so nice otherwise I forgive it. It's quite narrow & off the ground too & it all adds up to body roll and wear on the outer edge of front tyres.
