GoMopar440

Like the title says, I'm trying to address the severe trammeling issue on my 42K mile 97 Camaro SS. It's still in excellent shape overall and still almost completely stock. The tires that came on teh car are Hankook Ventus Plus's in the stock size 275/40ZR17's on the original ZR1 17x9 wheels.

Tire wear appears normal at all four corners. On smooth roads the car tracks fine and feels smooth with no left or right pull or vibration during acceleration, coasting or braking. On roads with even a slight amount of rutting, the car gets tossed around by the front tires pretty badly. The rear of the car tracks fine (unless I mash the go pedal )and the car feels solid in every way, besides the trammeling that is.

Since I plan on using this car for a DD (after the weather lets up here in MT) I'd like to get it feeling a bit steadier when going down the road. I'm not going to be drag racing this car, but I do like to have good solid cornering abilities for the twisty mountian roads we have in abundance around here.

I'm wanting to switch to a high performance all season tire as these Ventus's are just not cutting it. They feel like a summer only tire that wants to break the rear end loose at the slightest hint of moisture on the road. This is even when driving in a safe and sane manner since I know these tires arent ideal for my current area and or application. I hardly ever drive the SS at this point till I get these issues resolved.

I had a few questions I was hoping I could get some answers from people here with first hand experience on the subject. The CZ28 forum search function mostly just yielded suggestions for threads about drag race setups or larger tire/wheel combo's or lowered vehicles.

- Are there any recommended alignment specs that differ from the standard SS factory specs that I should be using? (What are the 97 SS factory alignment specs and where would I find them BTW?)

- Does anyone have any suggestions for a good performance alignment shop in the western MT area? Somewhere between the Missoula, Butte (closest to me), Bozeman or Helena areas? I just recently moved here so I'm still learning the area.

- Are the Ventus Plus tires more prone to trammeling than other brands of tires?

- Are there any brands of tires that typically have the least amount of trammeling effect on a stock suspension height '97 SS?

multicar

Not sure if the SS alignment specs are different then the z28 ones. You can call tech at slponline.com and maybe find out. The standard 96-97 camaro specs(including z28's) are:

caster: +5.0 plus or minus 0.5degrees
cross-caster: 0
camber: +0.4 plus or minus 0.5degrees
cross-camber: 0
toe: 0 plus or minus 0.2degrees

Mine is not set to factory specs and here's why...
First w/5.0 caster, the steering effort is too much and results in sharp kick backs to the steering wheel, which if you don't have the death grip on it, it will move the car around.
I like 4.0 caster.
Second w/+0.4 camber, the tires will wear on the outside edge.
I like -0.3 camber.
Third, I don't have a explanation for the toe, but it seems to complement the other changes.
I like 1/32" toe in.

When I got my alignment done, it wasn't easy finding a place that would put it where I wanted it. Essentially, I would ask them if they had the special tool to assist in the alignments for 4th gen f-bodies(see rock auto for a pic). This tool makes the process 10 times easier for them, as it holds the lower a-arm in alignment while they concentrate on tightening the arm bolts for the caster and camber. If they don't have the tool, walk away and look for another shop. I finally found a shop that would do it and the mechanic put my specs right on the nose. I tipped him a $20 after he allowed me access to the alignment machine to verify the settings.

Wild Willy

Trammeling is a common effect of the low aspect ratio tires like you are running. I have both 16's and 17's for my Camaro, and sometimes switch back and forth- the 16's ride much nicer, too, besides being far less "darty" and affected by road surface. The 17" wheels look great, probably have a higher ultimate grip, but you pay for that performance benefit in ride quality and steering feel.

GoMopar440

The 17" ZR1 wheels are factory original to the car for the 96-97 SS coupes. I'm not sure about other years though. The convertable SS's got 16" wheels for some reason but I want to keep the stock 17's on my coupe since thats the way it came. I'm also wanting to stick with the stock 275/40ZR17 tire size as well. Not looking to change that either. I'm open to different tire brand or model suggestions though.

I'll give SLP a call and see if they can give me some alignment suggestions. If so, I'll post them here. The SLP SS owners manual has a comment in it about the tendency of the 17" tire/wheel combo to have the trammeling effect. So, I'm not really sure how much I'll be able to correct for and how much I'll have to just learn to live with.

BTW: Doug, what size and brand of tires and wheels are you running with those specs?

GoMopar440

I was just wondering if a strut tower brace might help. Anyone have an opinion on the effectiveness of these braces? I found one made by SLP for the 96-97 SS. Are they worth it?

multicar

I'm running the z28 spec size 245/50-16 using Pirelli Pzero-nero skins. At any speed, they seem to respond the same...very predictable. According to their website, they don't make that size anymore, though. Mine are at half-life.
The strut brace alone won't solve the issue. Might help a little.

TD95Z

Definitely a side effect of the tire width. With the stock 16's and 235mm tires on my TA, it was easy to drive. I'm currently on 17x9 ZR1s with 275mm tires at all four corners, and the car is all over the place on our miserable Ohio roads. It must seriously look like I'm driving drunk the way this thing darts back and forth. Running some fairly inexpensive Coopers, for the record.

GoMopar440

Except for the brand of tires, that setup and handling description matches exactly how my SS handles. Good to know It's not an isolated case at least.

I got an email back from SLP customer service saying they received my question via email and that they would call me back sometime in the future. I'll post up whatever they say about it whenever I hear from them.

Procharged94Lt1

My car darted all over when I had 275's up front.

I dropped down to 245's and it was a night and day difference- It still darts here and there but nowhere near what it did before.

Running a narrower tire in the front would be the first place I would start- In all the miles I have driven the car, through the twisty roads and such- it was ALWAYS the back end that stepped out first, even with the 245's up front. Unless you are autocrossing your car, 245's should be sufficient I would think.

GoMopar440

I'm keeping the stock 275's up front as that's what came on it originally. I'm not a drag racer, but I wouldn't mind trying my hand at autocross sometime in the future. Therefore I plan on working within the limits of the 275's. If I change anything tire size wise, it'll be to up the rears to 315/35-17's on 17x11's. That won't be happening for a while though, so I just need to work on the setup for the 275's for now.

BTW: typing this all out on a phone sux. LOL!

JETMAN95Z28

I have a '96 Z/28 I bought a set of 2000 SS 10 spokes with the SLP factory 275/40ZR-17 F1 tires all around. I noticed the same thing immediately after bolting them on. I got a little used to them after awhile. I recently added a set of UMI sub frame connectors and it really made a big difference, and drives much better than before. I also added a set of Koni adjustable shocks. Between the 2 changes it drives like a new car. Like TD95Z drive on these ratty Ohio roads and they are the worst.

GoMopar440

How did you like the UMI subframe connectors? How do they compare (fit, instructions, effectiveness, etc) to the SLP ones?

I'm thinking of picking up the SLP strut tower brace and the SLP subframe connectors soon. I'm not stuck on SLP, I just figured I'd like the try to keep the same vendor/manufacturer for the upgrade parts. Anyone else I should look at for these parts? I'd prefer weld in, but I figured I could also just do bolt-ins and then weld them solid after bolting them in place.

Any thoughts which way is better? If so, why?

BTW: Still no reply from SLP yet...

Wild Willy

UMI has great customer support. Mine made a noticeable difference in solid feeling and creaks and groan. Highly recommend this mod.

JETMAN95Z28

My UMI 3-Point SFC's are top quality pieces that fit and finish were perfect. I've yet to actually need the UMI customer service dept. but the fact that SLP has yet to even reply to you would make me cautious, in case you ever really needed help after an install issue. I've read nothing but good words about UMI and their customer service. My car is much tighter and less likely to follow every bump and groove in the roads. With this awful winter I haven't had a chance to put very many miles on it since the install, but my initial impressions are very positive.

GoMopar440

The weather's been nice enough for me to drive the SS around a bit this past month so I've been taking it out as much as possible. What I've noticed in the past 1000 miles is that some roads have been worse that others for trammeling. If the roads are decent then it's not bad at all, poor roads however feel VERY bad. Most roads around here fall somewhere in between.

I still haven't changed anything with the car yet as I was wanting to get some more feedback on the problem first. What I've noted from the miles put on the car is that the outer edge of the drivers front tire has gotten almost bald in the past 1000 miles. There WAS still tread on it before I started driving it. So that leaves me with two things on top of my "To-Do" list.

1) alignment
2) new tires

Once those are done I'll reevaluate the handling and take another look at the possibility of implementing the other ideas if needed (STB & SFC's).