Stumped: Vibration at 70 mph RESOLVED

charlesh · Post by **charlesh** » Tue Nov 30, 2010 12:22 pm

I have new engine mounts, new lower control arms (both sides), just got new inner tie rods (both sides) and alignment. Tires are all inflated to 33. Starting last week, my whole car shakes at 70 mph. Its like clockwork. The shake feels like its a bad tire, but my tires have less than 20,000 miles. The inner edge of the front driver's side tire has worn, probably because of the inner tie rod or bad LCA bushings that were on there before. Also FYI, I have 18" rims on the car. Any ideas? tips on troubleshooting this?

sidepipe87 · Post by **sidepipe87** » Tue Nov 30, 2010 12:28 pm

bent wheel, bad cord in a tire?

Post by **occasional demons** » Tue Nov 30, 2010 12:29 pm

Have the tire balance checked on all four tires. Go from there.

charlesh · Post by **charlesh** » Tue Nov 30, 2010 12:42 pm

I had an alignment done yesterday. Is checking tire balance different from that? If so, how do I do that?

Dylan-00Blue · Post by **Dylan-00Blue** » Tue Nov 30, 2010 12:52 pm

step 1: drive to local tire shop

step 2: walk inside

step 3: ask to have all 4 of your tires balanced

step 4: pay for service

step 5: drive away

step 6: report back to tell us if it fixed the issue

sidepipe87 · Post by **sidepipe87** » Tue Nov 30, 2010 12:59 pm

a wheel alignment and tire balance have absolutely nothing to do with each other.

Post by **racer12306** » Tue Nov 30, 2010 1:04 pm

An alignment checks the straightness of the suspension in accordance with OEM specs.

A tire balancing checks the balance of the tire, and the tire only.

Post by **occasional demons** » Tue Nov 30, 2010 1:12 pm

Most places will check the balance, before actually doing it if you request, but you may still need to pay for them removing the wheels.

Even if they are not out by much, insist they balance them. My jeep had a shake problem at 50 mph specifically. The front tires would literally move back and forth about 3 to 4 inches. It was out less than an ounce on all four tires. The tire place tried to tell me it wouldn't fix the shake. I insisted on a rebalance anyways, and the shaking was totally gone.

IMHO, a re balance should be part of every alignment. It would solve prolly 85% of post alignment complaints, save the customers, and shops a lot of time. I know they wasted a few trips back and forth of my time due to a few miserable onces of lead. They even test drove it, and just couldn't understand what was wrong, and this was at more than one place.

theColonel · Post by **theColonel** » Tue Nov 30, 2010 2:02 pm

Another possibility is that the tires are "cupped" .... you should be able to feel that the surface is uneven .... it happened to me once .... I don't remember the cause,
but the recommended cure was to replace the tire

fixitmattman · Post by **fixitmattman** » Tue Nov 30, 2010 4:56 pm

Try it at 88 and see what happens.

Post by **Canada** » Tue Nov 30, 2010 5:00 pm

LoL Matt. He is only allowed to do that if the flux capacitor is not running.

Try and find somewhere that has a road force balancer, much more effective.

darthroush · Post by **darthroush** » Tue Nov 30, 2010 6:39 pm

lol. I have the tire shop check the balance every other tire rotation. It's one of the included services with the tires. Free rotations, balances and so on.

charlesh · Post by **charlesh** » Tue Nov 30, 2010 7:31 pm

fixitmattman wrote:Try it at 88 and see what happens.

Well, it's a little better at 80. The worst is at 70. I usually keep it under 88 cuz that's where the warp drive kicks in.

Tires look fine to me. When I get a chance, I'll have the tires balanced, and have them check if a rim's bent.

fixitmattman · Post by **fixitmattman** » Tue Nov 30, 2010 7:52 pm

Sarcasm aside, kinda sounds like when I had a bad tire. Try swapping the tire to another position, if the vibration moves with the tire it's a bad or unbalanced tire. If it stays where it is, the problem is in the running gear at that corner. If you find it goes with the tire, try balancing that assembly. If it only stays balanced for a bit then goes off again you'll need a new tire.

Your rims, are they hubcentrics?

charlesh · Post by **charlesh** » Tue Nov 30, 2010 8:18 pm

Good question! Being a n00b and all, I'm finding out all kinds of shit I didn't even know I didn't know. I'll google hubcentric and find out tomorrow what I have.

Post by **occasional demons** » Wed Dec 01, 2010 7:19 am

Canada wrote:
Try and find somewhere that has a road force balancer, much more effective.

The funny thing is they put the Cherokee tires on that, and it showed them as fine. Still took an old fashioned re balance to correct the problem. It was the Hunter 7000 or w/e it is called. (It's been more than a few years)

The problem was more all four tires were working together, vs just one tire. It's tough to test all four at once on one machine.

charlesh · Post by **charlesh** » Thu Dec 23, 2010 2:32 am

Finally got it fixed.

I bought 2 Kumhos Ecsta ASX for the front, and still there was a shake. So they rebalanced all 4 tires, and the problem was with the back tires. The right one was out of balance, and the back two rims were missing hubcentric rings, so those were put on.

On the plus side, I got those cheap Chinese tires (Talon Triangle) off my car and the Kumhos are fantastic.

Bzevey · Post by **Bzevey** » Thu Dec 23, 2010 7:38 am

I had the same thing on my black car, tires were shot and it would start shaking at 45 already. Took wheels off and the rear tires had bald spots on them.

charlesh · Post by **charlesh** » Thu Dec 23, 2010 1:39 pm

In the process I found out my shocks are gone, which I'm not surprised since the previous owner lowered the car by simply cutting the springs. So I know the next step: Tokico Blues and Eibach Pro Kit!

Passt · Post by **Passt** » Fri Dec 24, 2010 12:07 am

Glad you resolved the issue:)