I was just reading the alignment stuff on Ogre's site. Great stuff. Go browse his whole site if you have never been there.
We probably did not rotate the tires on the 88's as much as we should have and on an 88 you really can't rotate stock tires since the rear ones are different from the front ones. The tires are worn enough more on the inside to make it really noticeable near end of service. Is that -1 degree of camber the reason or was our alignment off?
Now that we have three GTs (two 88's and an 87), does anyone have opinions of making the two 88 cars have the same front/rear wheel sizes in order to have 4 same tires on each car? One would have wider wheels/tires and the other the smaller ones. I know I have heard of issues on other cars with bearings, etc going to wider tires. On Kevin's last time, we put the same size all around and just put a slightly undersized tire on the wide wheels.
I was just reading the alignment stuff on Ogre's site. Great stuff. Go browse his whole site if you have never been there.
We probably did not rotate the tires on the 88's as much as we should have and on an 88 you really can't rotate stock tires since the rear ones are different from the front ones. The tires are worn enough more on the inside to make it really noticeable near end of service. Is that -1 degree of camber the reason or was our alignment off?
Now that we have three GTs (two 88's and an 87), does anyone have opinions of making the two 88 cars have the same front/rear wheel sizes in order to have 4 same tires on each car? One would have wider wheels/tires and the other the smaller ones. I know I have heard of issues on other cars with bearings, etc going to wider tires. On Kevin's last time, we put the same size all around and just put a slightly undersized tire on the wide wheels.
Could be a combination of both camber and toe causing it. Have it aligned, especially if the bushings have never been replaced in which case an alignment will not be enough in the long run.
if outside is good but inside is "bald" then have alignment problems. If outside is worn out, like close to same, then minor alignment problem that you might never find exactly what's the problem. If tire is worn fast... look for toe error. bad toe can wear very fast.
Most Fiero have 1 tire and rim. If total diameter changes much then will mess w/ speedo and total gearing of trans. most covered in gearing in my cave.
I don't like mismatch rims because tire changes profile of tire when mounted on different rim width. Can cause very odd things to handling etc. Tire spec matter. Test rim width is how tire is made for. min/max rim width is what tire is safe to use on. Many tires use Same test rim but Mim/max can change for brand etc. Most are covered at tire maker site and some vendors.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
I bought a set of 16x8 wheels (I forget the offset at the moment) to mount my 225/50/16 autocross tires (on all four corners) for my Formula. The idea of course was that it would be advantageous in regards to tire rotation. It's more than possible that my alignment is off a bit, but I hate driving the Formula on the street with this tire/wheel combination. The front tires want to follow any ruts or crown on the road, and I've got to be hanging onto the steering wheel tight! With narrower tires and narrower/less offset wheels on the front, there's no such problem.
When I replace my autocross tires (using the same 16x8 wheels), I'll probably try using 205/55/16 tires on the front while retaining the 225/50/16 size on the back.
[This message has been edited by Patrick (edited 07-13-2016).]
Alignment is probably the problem with your un-even tire wear. I have owned my 85 since new- The tires have worn evenly(15-17 sets).
Patrick, the tire tread pattern may be what is giving you fits. I had some tires that would tram-line all over on I280 on the way home from work....Changed to a different tire and no such problem. C&D was testing a Mustang GT in their Lightning lap test and it was delivered with the wrong tires- They said it absolutely sucked- Then they had the right tires installed(Pirelli P Zeros I believe) and the whole character changed....Turn in better, feed-back improved- The car was substantially quicker around the VIR track.
Patrick, the tire tread pattern may be what is giving you fits...
Hmmm... I hadn't considered that possibility. The tires are Kumho Ecsta XS. This might be the last year I use them though, as they're getting quite worn. I usually leave these tires/wheels on the car during the summer months, but they're now scary/dangerous on the freeway in the rain.
I am going to go with wrong camber based on Ogre's response. These are the rear tires that are wearing crazy, so toe is likely not the issue. Not sure how much you can adjust the toe, but it looks possible since one link is adjustable.
The numbnuts who did a clutch job on my 86 one time somehow got the lower ball joint bolt in rotated 180 degrees. it gave like 10 degrees of camber. Peeled the rubber off on the inside in about 300 miles.
Given what I found on the right side when I replaced the spindle, it is going to be interesting to see if I can find a shop to do a proper job of setting the camber.
88 is the only year that Pontiac used wide tires/rims on the back and smaller ones on front. I'll have to check the specs, but I think the back ones were 225 tires and the front ones were 205.
Originally posted by Ray_and_kevin: I am going to go with wrong camber based on Ogre's response. These are the rear tires that are wearing crazy, so toe is likely not the issue. Not sure how much you can adjust the toe, but it looks possible since one link is adjustable.
Uh No... Rear toe is on most cars except "Solid" rear axle. (Some FWD cars etc use(d) solid rear axle setup too.)
So does anyone have experience or even an uneducated opinion of making one 88 have four 7" wheels and the other 88 have four 6" wheels? It is a real pain when it comes time to rotate tires. Seems like a bad idea to put the big ones on front and the little ones on back.
It is time to buy 8 new tires real soon now, so I am trying to figure out what makes sense.
Originally posted by Patrick: I bought a set of 16x8 wheels (I forget the offset at the moment) to mount my 225/50/16 autocross tires (on all four corners) for my Formula. The idea of course was that it would be advantageous in regards to tire rotation. It's more than possible that my alignment is off a bit, but I hate driving the Formula on the street with this tire/wheel combination. The front tires want to follow any ruts or crown on the road, and I've got to be hanging onto the steering wheel tight! With narrower tires and narrower/less offset wheels on the front, there's no such problem.
When I replace my autocross tires (using the same 16x8 wheels), I'll probably try using 205/55/16 tires on the front while retaining the 225/50/16 size on the back.
I experienced the same but with an 18x8 and 18x9 setup with 225/40 on the front. I believe the cause was more alignment and tire choice related. My situation became extremely dangerous on the interstate when it started to rain on I75. The car was guiding so hard alternating left and right with road changes combined with puddles I had to slow to 35 mph in a 70 mph zone to keep the car from swapping ends if I had attempted to fight it aggressively. I literally had to let it take me into another lane until I could slow it down enough to safely correct it. Bias ply tires are notorious for that kind of behavior and although I had some rather cheap radials (from Russia I believe that gripped like plastic), they performed like a set of bias ply tires I used on a Firebird before I gained any knowledge about tire performance.
Keep in mind the Fiero is light in the front and wide tires work great on dry roads but just the opposite on wet roads where a wider tire is more likely to hydroplane due to less weight per square inch especially if the tread is on the low side. I have new matching brand tires all the way round now with the same size on the front and 245/40 on the rear and the car drives fine on wet roads at speed however a deep puddle can be a bit of surprise if you don't see it coming. Next time I'll search out a 215/40-45 for the front. At $65 each on sale I couldn't pass up the Radar from Sears in that size 225/40.
As to the OP, keep the staggered arrangement, go with a set of tires that you like and have the car aligned. Fieros are not that hard on good tires and there's nothing wrong with rotating a radial tire from left to right as long as it is not directional.
[This message has been edited by Joseph Upson (edited 07-29-2016).]
The general rule I follow is measure the width of the rim at the bead and buy a tire with that same measurement across the flat treaded part. Putting too wide or too narrow of a tire will cause either the inside or outsides of the tire to wear faster respectively. Your issue does sound like a camber issue.
[This message has been edited by rogergarrison (edited 08-05-2016).]
