FireInMe17

Ok so I have a 1990 Camaro RS that came standard with Z28 wheels. Today I went and got 16" IROC's with brand new tires on them for $300. The tires are different front and back but I don't really care.

As soon as I got back from getting them, I went and got them put on. They look great, but now the car rides like hell. Shaking from side to side, bumpy, like they aren't balanced at all, but I've never had it so bad like this before. I think something else is wrong.

What else could go wrong with switching between these two tires?

The only thing that I can see wrong is that the front tires are 245/50/ZR16's and the rears are 235/55/R16's. Am I wrong, but aren't the wider tires supposed to be out back and not in the front? The guy told me that they should be staggered with the taller ones in the rear, but they are both the same height with the different sizes, and having such wide front tires makes the car jerk from side to side with just the slightest touch of the wheel.

I think that thats part of the reason why the car shakes from side to side. And I'm positive that they aren't balanced right, they can't be because the Camaro used to ride smooth as glass with the old wheels balanced properly.

Any one have any ideas? And what is the proper staggering? I think it makes more sense to have the bigger tires in the rear and the skinner ones in the front.

chazman

iTrader: (4)

Are you sure they're balanced? Are the tires unidirectional? You know that IROC wheels have specific offsets for front and rear, right?

FireInMe17

Yes, I know that the IROC's are front and rear specific, and I told the dumbass that put them on, but I still had to go out in the garage and tell him that the reason they wouldn't fit was that he was trying to put the rear tires on the front, and the dumbass busted out one of my center caps in the process....even with the wheels saying FRONT and REAR on them.....


BUT, the tires are unidirectional at least the Nittos are, they are the 245's, and I'm not sure what the 235's are brand wise. I know its supposed to have 245's all around but I'm not complaining for $300 wheels and tires.

Yes, they are balanced, I paid to have them balanced, and they have the weights on them, but I have had problems once before even with my old Z28 wheels that right after I've had them balanced it did the same thing, but not anywhere near as bad.

But staggering shouldn't be an issue if the tires are the same height front and back, even with having different profile heights. They might be just a LITTLE bit off, but nothing major that it would even matter. So then the wider tires should be in the rear, given that the rear wheels are the driven ones and all....right?

chazman

iTrader: (4)

If the tires are unidirectional, are you sure they're not on backwards? And I'd have them rebalanced just to be sure.

FireInMe17

I guess I'll have to check to see again...I still can't get over the fact that this guy couldn't read REAR on the wheel that he tried to put on the front. Maybe he did put them on backwards. Wouldn't surprise me. And they better damn well rebalance them for free.

camaronewbie

Also, get a wonderbar installed asap. Either from a JY IROC, or get one from TDS - the wonderbar is needed, especially with the 16" wheels.

FireInMe17

I thought I was getting a wonder bar with my last trip to NJ to get parts for my 305 Vortec TPI swap, but I didn't. I'm definitely getting one though. I'm sure it will help with the shakes, but these are just really REALLY bad now with the 16" wheels installed. I think I can hear the gas tank rattling around in the back like a tin can it shakes so bad now....

CruzinQueen

I just replaced the 16" Z-28 wheels with 235/55/R16's with IROC 16" 245/50/R16's on all four and have not had any issues with shaking. Personally, I believe that the wider tire (the 245's) should be in the back, but I'm not for sure on these cars. Also, like others have mentioned, make sure that the tread is going the correct way and perhaps have them re-balanced. I'd be leery of anyone who can't read the "FRONT" and "REAR" stamped on each wheel. Good luck to you!

JamesC

iTrader: (5)

You might verify that the lugnuts are tightened to spec (Hey, the tech was a nimrod, right?)

JamesC

FireInMe17

Alright, will do. Thanks for all the help guys, I'll let you know how it turns out.

mr305

iTrader: (1)

What model nittos are they??? some tires have a harder compound that makes them ride rough i had some futura gls's and my car rode really rough and when i put brand new kumho's on it it rode soo much better and both tires were the same size

FireInMe17

Nt450's I'm pretty sure

87IROC-DAN61

Hello FireInMe17!!

Did the tire person check your wheels for trueness???

Tires can be balanced properly, however if the wheels run "wobbly" you will get a really weird feeling, also did you get the front wheels aligned using the IROC-Z specs???

Check also if the tires are actually mounted to run in the right direction on both sides, this makes a big difference!!

As for the tire sizes, I personally would run only the same size on all four corners, that's just me, staying true to the factory set up!!

Also, there are some rubber bump stops that need to be changed for the 16 inch wheels!! These rubber bump stops are different from the 15 inch wheel ones!!

There are also spacer plates used for these wheels on the rear only with drum brakes!!

Wheel nut torque is 100 lb ft!!

How "new" are the tires???

Check tires for broken steel belts, this usually causes a "wobble" and should be picked up at the time the wheels are balanced!!!

JamesC

iTrader: (5)

Though designed for drums, some J65 cars were equipped with the spacer--GM, what a bunch.

Interestingly enough, my shop manual says 80 lb ft.

JamesC

camaronewbie

I always do 80ft lbs too. Shops on the other hand always do 100ft lbs - then when you need to change one on your own, you can't get the lugs off by hand! I always insist they let me tighten my own lugs by hand when I get tires changed at a shop. If they say no, I tell them to put my old tires back on cause I'm not paying them!

FireInMe17

I guess the reason they gave me for the tires riding so rough was that the front ones had bumps in them, and the Nittos were over inflated and are wore in wrong as a result. BUT, after getting the tires rebalanced it rode better than it has the entire time I've had it, three years so far. Then later that night I took a hard turn and it was back to square one.

I'm starting to think that I need to replace all my bushings and some of my suspension components....I've seen tires wore the wrong way much worse than the ones I have on it now, and those cars have not had any problems with drivability and comfort.

The tires are mounted correctly with the unidirectional tires going the right way, they probably aren't torqued to 80 ft/ilbs though, I'm sure they did 100. Haven't had the car aligned seeing as how every time I do get it aligned, the alignment gets worse, further proving the fact that I need to do some work on the suspension and steering....

Getting factory sized tires isn't really an option at this point, and finding the 245/50R16's are hard to get in a decent tire, and if it were me, I would have the same sized tires front and rear, but I can't help that with what I have to work with.

What do you mean rubber bump stops?

Guy said that the car got new tires and a whole new engine 500-1000 miles before his friend parked it. The guy said that he knew the car from the previous owner and the PO, and bought it off of him to restore, but decided to part out after finding too much rust, so the tires are almost new I'd say.

The guys at the shop told me to run the car on the highway for a while and that should straighten them out and it will get better once the bumps are sorted out and the Nittos start to wear right, but after driving it on the highway last night, at variable rates of speed, it only got worse. So now I don't know what to do for sure....

lb9 GTA

If it sat for a long time the tires might have a flat spot on them.

lb9 GTA

The shops tell you "no" because they are still liable if anything were to happen reguarding that wheel. I mean absolutly no offence by this, but I'm shocked that any shop will let you tighten your own wheels. FYI That 80ft lbs is actually +/-10ft lbs. I usually torque mine at 85-90ft lbs but as little as 70ft lbs is acceptible.

87IROC-DAN61

Hello JamesC!!

I have seen in the FSM the rating of 80 lb ft too!! I have also seen the rating of 100 lb ft in other manuals, but the other manuals state that it is for the cast wheels..........now having said that, IIRC I have seen the 100 lb ft rating in a FSM, and I have been looking for it again to verify it.......just haven't been able to locate it!!

For what it's worth, the owners manual states 80 lb ft too!!



As with all things technical, there are revisions to specs, and I do believe that is why the "tire shops" use 100 lb ft!!

As to why other manuals say there are two different specs, one for steel wheels, and one for cast wheels, I can only "guess" that it has something to do with steel vs aluminum, (and now for the pure speculation) the fact that they have different rates of heating and cooling, and this could cause a loose wheel condition leading to the loss of a wheel, hence the 100 lb ft rating!!



I've been using 100 lb ft for my wheels since 1987, and it works for me, I have not seen nor felt any harm being done!!

87IROC-DAN61

Hello FireInMe17!!

The rubber bump stops are on the lower control arm, 15 inch wheels and 16 in wheels have different bump stops!!

For what it's worth, you could probably get away with using the ones that you have, and never ever need to worry, but to make it all 16 inch wheel factory correct, "I" would get the correct ones installed!!

87IROC-DAN61

Hello camaronewbie!!

Try using a four way wheel wrench instead of just your hand!!

It's easier that way!!



I always get the shop to do the lugs by a hand torque wrench, no hand torque wrench, no business!!

Some shops do it all the time with cast/aluminum wheels, some don't, I don't go to those shops!!

I always bring my torque wrench to the shop, and retorque the wheels in the parking lot, that way I know what the torque value is!!!!

JamesC

iTrader: (5)

I just tool a peek at my 91 Bird shop manual, which says: ALL at 100.

JamesC

87IROC-DAN61

Hello JamesC!!

I had a peek in my 1989 FSM, and it said all at 80 lb ft, just as my 1987 FSM said!!

As I stated above though, specs do get revised, and one of my FSM's is a reprint, and the other is an original........I hope!!

So, based on my, and your findings, something made it change between 1989 and 1991!!

hellz_wings

iTrader: (2)

1)16" 1986 iroc wheels: What is the torque spec for lugs?

2) Can you torque the lugs if the car is sitting on the wheels (and not on a lift?)

Thanks!

//<86TA>\\

iTrader: (15)

i only torque my wheels to 50 ft/lbs, hmmm, maybe i should tighten them a little more, never had a issue though

JamesC

iTrader: (5)

1. 1985 and 1987 say 80. I wouldn't think it would be different for 1986.

2. I usually torque the lugs with enough weight on the wheel to keep it from turning. But that's just me.

JamesC

hellz_wings

iTrader: (2)

Okay cool thanks man.. 80lbs should be fine.. I've already lots lug nuts in the past or have had them loosen :S .. Making a very strange noise in the rear. Scary thought of loosing a wheel crossed my mind when that happened and now I just tighten them as tight as I can in my driveway once a week, although I should go out and buy a torque wrench to know the exact spec i'm tightening them to. Thanks again!

FireInMe17

I find it kind of hard to believe that there could be a flat spot on the tires, my Blazer sat for 4 years, and I drive it around with the same tires on as when it was sitting and it rides excellent.

87IROC-DAN61

Hello hellz_wings!!

Start with the car jacked up, install the lug nuts, "snug" them up in a star pattern with a wheel wrench first, this will help center the wheel with the lug nuts, (for a front tire) lower the car until the tire just contacts the ground (this prevents the wheel from turning), and then using the torque wrench in a star pattern, torque them down!!

For a rear tire, use the parking brake to hold the wheel from turning!!

Once this is done, lower the car the rest of the way, and then check the torque once more, in a star pattern!!

This is how I do it!!



Weekly/monthly (your choice) check the torque in a star pattern!!

A "click" type torque wrench is the best for this!!



Also, I use 100 lb ft for my torque value!!

UnderCover89TBI

iTrader: (25)

100 lbs is what I torque mine too. Now I just put new wheels on awhile ago and broke 2 studs. but I think the previous tire shop I went too did not torque them properly. I use a click torque wrench.

87IROC-DAN61

Hello UnderCover89TBI!!

What did the previous tire shop torque your nuts with??

Hand torque wrench, or the pneumatic one???

hellz_wings

iTrader: (2)

Thanks IROC dan, I'll do that next time I got the car up on the lift. I guess it would be safe to say 90lbs is the safest route?

karl's-92'-z28

iTrader: (5)

I say take the front off, put your stocks on & see what happens, then same with the rear. A rim may be warpped. What type of wheels weights are they using? Stick on & are they static balancing the rims? I say take it to a Goodyear of Firestone & tell them your problems, since they are tire experts, they should know whats wrong.

FireInMe17

I took it to a bastians tire and auto center, but I've never really been there so I can't say how good they are or not. But speaking of the rear wheel spacers, do you think they will really help out the rear? It feels like most of the shaking is coming from the back now. I think the front tires have straightened themselves out....

87IROC-DAN61

Hello hellz_wings!!

90 lbs will work, as will 100, but don't exceed 100 lb, this is where it will start to get problematic!!

hellz_wings

iTrader: (2)

Haha yeah last thing I want is a snapped stud!! Thanks man

UnderCover89TBI

iTrader: (25)

Im assuming they used an air impact gun to whatever desired torque they want. they were tight but too tight im sure.