Tire Wear Questions on an '86 Bertone

[Cratecruncher]

I'm going through my new to me '86 and have finally gotten to the tires. From the pics attached it's obvious the tires in the rear have worn unevenly in what I presume is caused by severe negative camber though none of the wheels look angled in at all. The tires in front are also showing the same pattern but not so severe. I don't know if the tires were rotated to different positions since they were first installed. The car only has 21k miles on it and I doubt it's ever had an alignment. The previous owner only put 5k miles on the car in his 21 years of ownership and these tires are newer than that! My Bertone factory answer book says camber is "unadjustable" which seems odd. Before I buy new tires I want to give the new tread a fighting chance.

Questions:
1) Is this wear pattern common?
2) What are the causes?
3) How do you adjust camber on an X?

 

[Pete Whitstone]

1) Yes, very.
2) Negative camber can be a cause, but it would take a lot of negative camber. Excessive toe is a far more likely culprit.
3) Non-adjustable by factory means, but you can:
a) install camber (or caster-camber) plates
b) use camber bolts on one or both of the lower strut mount holes (where the strut bolts to the hub)
c) slot the upper hole (of the lower 2 on the strut itself) to allow some adjustability, optionally install a metal wedge between the strut body and hub, then tighten the hell out of the bolt
d) slot the upper hole, find and mark the right camber, weld a washer over the new hole location. Kind of the same as c, only you don't have to tighten the bolt as tight or worry about it slipping. DO NOT DO THIS on sealed struts. This is only advisable on strut bodies that have removable inserts.

Pete

 

[carl]

Toe in is adjustable at both ends of an X, right? I'd check to see if toe is out before trying to adjust camber.

 

[Cratecruncher]

Thanks for the help everyone!

I had the car up on jack stands when those pictures were taken. I took the car for a drive and then looked more closely at the wheels. Just eyeballing down the length of the car it appears there is much more negative camber in the back wheels than in the front. I'll try and get some shots of the wheels resting on the ground tomorrow. I have an cheap toe measurement gauge. Using on the back wheels I got 6/32" in back, I think. I'll take better measurements tomorrow with a tape. I think that gauge is a piece of junk. I'll also try to get some decent camber measurements for each wheel.

It doesn't look like any of the suspension fasteners have been touched on the car. I saw some offset camber bolts and those wedges for sale on Ebay. The offset bolts seem like they would be the easiest to use but not sure. Do you have to modify the strut or upright if you just use the bolts? Can anyone recommend a specific set or part number?

 

[JimD]

What do the rear strut mounts look like? The strut shaft should be pretty centered in the donut. As the mounts age, the rubber donut breaks down and the shafts tip in towards engine. That can make the tires tip in as well.

 

[kmead]

The camber isn’t the only reason for the wear, as was pointed out above it is more likely due to excessive toe, toe out in this case. Toe in will wear the outside edges of the tire, toe out will wear the inside edges of the tire. Excessive camber can excacerbate the problem but is unlikely

The suspension is set up to have more negative camber in the rear, the front is also set up for some as well. The standard spec is -.5°=/-.5° the rear is -1.5° =/-.5° Yes it is non adjustable as standard from the factory.

Assuming you actually have excessive negative camber, first take a pic of the top of each strut tower, the two in the engine bay and the two in the front trunk. As the upper strut mount wears out, it will generally move the top of the strut inward due to the angle of the strut and the load imposed. On my 85 the front and rear upper mounts are very tipped in, to the point that the top of the mount is contacting the underside of the body, which is not good. The lower A arm bushings could be worn but to be worn to this point you would have other significant effects such as banging rattling etc.

The camber can be adjusted using eccentric bolts between the knuckle and the strut or adjustable upper mounts. Or adjustable upper mounts like these

Ultimately the first step would be to inspect the each part of the suspension for wear, replace those parts that are worn or perished due to age. Then get a baseline alignment with a full readout of where it was and what it is set at. If the camber is out of spec, you could bring four of the eccentric bolts with you to the alignment shop and have them do it all in one go. They aren’t terribly expensive.

 

[DanielForest]

What you describe is pretty usual. The rear is sagging more than the front and you got too much negative camber.

Toe adjustment is a nice thing to do, but I would also fit a pair of camber bolts in the rear. Don't order anything on eBay. You may end up with the wrong size, even if the seller is listing the X19. Go to a reputable vendor . I think I remember Chris Obert (FiatPlus) had some.

Camber plates are more my cup of tea but they are a little more extreme just to cure a little camber

 

[lookforjoe]

I'd get the toe checked first. Tires will definitely scrub like that, just as they will in the front from improper toe. Don't overcomplicate it until you've done what is straightforward. Any alignment shop can read out your settings anyway, so I'd suggest going that route rather than trying to do it DIY

Those look more like tractor tires than anything suitable for a fine handling sports car, so you'll want to get something with a better good weather pattern also.

 

[Cratecruncher]

You guys are great! It's so much easier when you have an idea or two what to look for. I will take the car in for a precision alignment but first want to see if there are any repairs I need to do before hand. Yes, the snow tires are not needed often in Central Texas so I'll opt for something a bit more sporting when I get to that point. The size is 175/70 R13 on Trons. I'd like to go 185/60 or 195/60.

I took some photos of my strut tops to see if you guys think I should replace the seats. Each picture is looking straight down with front of car at top of photo. I also had a chance to take some crude measurements for toe and camber:
Front wheels: -12/32" toe-out, camber: left -1.7 deg, right -1.5 deg
Rear wheels: -13/32" toe-out, camber: left -3.0 deg, right -2.3 deg

These measurements error is around +/- 5/32 and +/- 0.5 deg but a good ballpark for discussion. The toe-out surprised me. I always assumed a car with toe-out was twitchy and unstable. This car seems to handle pretty well but I haven't driven it much yet.

 

[rx1900]

Hmmm...something sure aint right here......either your toe measurement are way off - or - your toe is way out of whack. An X1/9 should have a wee bit ( maybe 1/16" to 1/8" or so ) of toe IN on the front, and a bunch more of toe IN ( maybe 1/4" to 3/8" or so ) on the rear. Note: those figures are from memory - check your shop manual for exact figures.

With the toe OUT that you measured, the rear end of your X would be swaying like a drunken Kardashian !!!

So for sure you would have to get your toe checked and adjusted. Unlikely that anything is worn enough to cause it being out. Either something is bent - or more likely your measurements were just wrong.....

From your pics - yeah sorry to say your upper strut mounts are....pooched. Those big gold cups should be perfectly centered in the openings, which indicates the state of the upper mounts. You will have to buy new upper mounts and install them. Luckily, it is really easy to do. Just buy some decent ones - there are some crappy ones out there. But even the good ones are pretty cheap - like $50 each. For sure do that BEFORE getting an alignment.

Of course, check the rest of the suspension too for wear and defects. With the low miles on your X, you should be okay. But check all the boots on the ball joints and tie rods. Check the ball joints and tie rods for any play. And the rubber bushings for cracking or age hardening. And the shocks for leaks or softening or bent.

By the way, the stock tire size in your year was 185/60-13. Or you can use 175/65-13. Do NOT use 175/70-13 or 195/60-13 as they will most likely rub.

Good luck. Hope this helps. Doug

 

[Cratecruncher]

Ok, went back and remeasured the toe and did find a big error on the rear measurement. The front is pretty much unchanged. The rears are actually TOE-IN.

TOE Measurement OLD RECENT
Front wheels: -12/32", -11/32" (toe-out)
Rear wheels: -13/32", +10/32" (toe-in)

I think I labeled the rear measurements backwards. I double checked the recent numbers to make sure I hadn't made an error. Weird set-up. I am going to check ball joints etc. and contact the previous owner and see if he might have rotated the front tires to the back at some point when he noticed the extreme wear.