Annoying shake

I recently replaced the wheels and tires on my 98' Aurora. I went with the cheapest tires I could, b/c they are only going to be summer tires. Still have the original wheels and Michelin energy tires for the winter. Anyways, I have an extremely annoying rumble at the 65-75 mph range. I do know that the discount tire shop I went to uses the Hunter GSP 9700 balancer. Do they need to be balanced better? Or do the tires just suck, Kuhmo Ecsta P245.50.16. Has anyone had any experience with this shaking? Any suggestions?

Kumho's are loud, but general decent performance geared tires. Is the alignment off at all? Kumhos do have an aggressive tread so it may be loud. I hated my Energys with a passion...but thats another story

Didn't notice them being overly loud. My steering wheel is definitely cocked a little to the right, however; I have never noticed that it pulls either way. You think it could be alignment over the balancing?

My dad had a similar problem to this, but with his Pontiac Grand Prix. The issue was that a tire was out of round slightly or had some sort of defect causing a slight imbalance at a particular frequency(speed) range. Tire could be flat spotted or something like that. I've had Kuhmo Ectas on my Aurora for the last few years and havent had any sort of issue like that. For the price, they aren't a bad tire at all. I have 4 new ones in my garage I'm about to have installed b/c my front two are wearing very fast. I'm pretty sure it's my struts though, which I have new ones and will be replacing fairly soon.

My ecstas wore out really fast and didn't seem to grip the road very well. I guess they were worth the half the price of other tires I paid for them, but I never had excessive noise on the highway. I replaced them with a set of Cooper Lifeliner SLEs. They are much more of a touring tire that make the ride nicer (yet they grip the road better in terms of less squealing).

I thought that Hunter rfb machine was supposed to pick out defects in the tires pretty well. At least that's what their web site claims. Could be just that your 70 mph shimmy is so tight it makes noise instead of shaking your car like a terrier with a rat :)

I would take the car back to the tire shop and demand that they redo the RFB and match the high point of the rims with the low point of the tires, and vice versa. There's a numerical value for roundness that you can obtain from the GSP 9700 - anything outside of 10-15 is out-of-round and the tires will need to be replaced (had this with my Dunlop SP Sport A2's - ended up replacing them after 40k with BF Goodrich Traction T/A's, were around $90/tire mounted/installed/road-force balanced, great tire, lots of sticky, NO VIBRATION).

Hope this helps,

--Robert

demand that they reballance the tires, and they check to remove any stick on weights that may be hiding inside that are somtimes ignored by places that usually just use the hammered on type...in most cases when it was dynamic ballanced there should be only one weight on each side of the wheel...you can also ask that they ballance it so that the weights only go on the inside of the wheel so they dont show on those unblemished rims...news

**UPDATE** Well, went back to Discount Tire. The tires "were definitely out of balance". So, they rebalance them, I jump on the highway, and of course, it's worse than before. So, I call discount tire up, they say, there's a couple things they can do. I ask what. 1.) A road force balance. 2.) Something about a hub ring? Looks like it's back to Discount Tire again tomorrow, ugh..... What I wonder is, why couldn't they have done these things while I was there today?

let me know how this works out for you

I thought any Magnasteer equipped car required a road force alignment. Odd...when I changed my tires, it was fine, no alignment issues at all (I changed em myself).

That only works when you have another set of rims tho ;) Next time, just ask em to mount and balance you new wheels in your new tires and install em yourself...its dead easy and I'm a mechanical idiot

It's not Magnasteer, it's the stiffness of the G-Body which causes the 66-71 mph vibration.

Decent tires which aren't out-of-round from the factory helps, too (had Dunlop SP Sport A2's which had the problem quite frequently, whereas the Traction T/A's were as smooth as glass right from the factory).

i had this problem on my last car, SOMEHOW they managed to get water in the tire, and everytime they balanced it the added weights to make it balanced, and they re-spun it and got different results, and finally gave up on it, but didn't tell me that untill i came back with horrible vibrations LOL

Well, it appears as though my rims already have hub rings. Somehow one tire was still out of balance. They also supposedly did a road force balance. All this, and I still have an annoying shake at the +-10 70mph range. Granted, it's back to being bareable, but why should I have to put up with bareable? Next step, another set of new tires, I guess. I will keep everyone posted.

OK, LAST UPDATE....I appears as though tire installers and balancers are not the brightest of people. I returned back to the original Discount Tire, and complained about my car shaking at 65-75mph range. At this point, I figured, I needed them to replace my brand new tires with ones that don't cause shaking. They insisted on rebalancing them again, I complied. Well, it appears as though the other Discount tire was putting the weights on my wheels over dirt and grime. So, guess what happens to those weights, they fall off. SO, they rebalanced, and everything appears to be fine. I guess if anyone out there is experiencing this, it is probably the balance of one or more of the tires being off.

I have Perellies(spell stupid) on mine. Smooth as silk.

I can't say that I have had the degree of shake that you are experiencing, but I have to be honest that I couldn't wait to get rid of the Kumhro Ecsta's on my 97. I can't really bash them too bad because they are $50-60 tires, but they translate alot of bad handling characteristics and the "feel" is hard. I can't understand why people say they are such great tires, because they aren't IMO.

I switched to Yokohama Avid H4's and these are a great alternative for $80-90. I like them better than the $Michelin's or the Goodyear's- which don't wear well. But I digress..

You may want to check you suspension, alignment, bushings, etc. to make sure the shake isn't a result of some suspension damage/wear. Also, the brake rotors on these cars are very thin and warp easily...this will give you a shake during braking.

THE WORST TIRES I`VE EVER HAD ON MY AURORA WERE GOODYEAR EAGLE LS. THE CAR WAS BACK AT GOODYEAR GETTING RE-BALANCED,EVERY WEEK FOR ALMOST 3 YEARS TILL THOSE PIECES OF SH!T WORE BALD. THE NEXT SET WAS THE BEST I`VE EVER OWNED,MICHELIN PILOTS. THEY WERE WONDERFUL.
NOW THAT I`M NOT RICH ANYMORE,I JUST BOUGHT A NEW SET OF FALKEN ZEIX`AT A GREAT DEAL , SO I`M GOING TO SEE HOW THEY DO. SO FAR SO GOOD...... :smile:

Hey!

New to the club! I am awaiting the tech service bulletins on my'98. All Data doesn't give the same info to owners as "professionals".

I have a friend who was an Olds Master Mechanic and he remembers that there was a bulletin that addressed the tire issue.

These cars want only the best, including top-of-the-line Michelins. GM was reccommending only these. I did notice one of the posts mentioned Pirelli's. Has anyone else put on expensive, high quality tires?

Ted

PS: Has anyone joined any of the DEX CRAP Class Action Lawsuits?

I have a rattle when I turn to the right. It's more of a clanging. Anyway, I can make it clang by rocking the car side to side. If I push up and down no noise. If the car is running the noise is louder. Anyone seen this condition.