Vibration at 70+mph

[dave1123]

I just got a '96 GTS, and it has a vibration in the front end at over 70 mph, but if you go slower or easy up to over 70 it goes away. I thought it might be the tires being out of balance, but one of the members here thinks it's more than that. Has anyone heard of that or might know what coarse of action should be taken to fix it? Thanks

 

[ElDiablo Viper]

It could be bold spots as the 96 does not have ABS.

 

[1TONY1]

Find one of these and have your tires/wheels balanced. There is also a locator on this site:
http://128.242.141.111/index.cfm

 

[Casey]

Check the tire pressure, if they are over inflated this could be a cause.

 

[dave1123]

Thanks for all the input, I'll check these first. I was also told it might be a worn tie bar and/or bushings. I'll need to put the car on a rack and take a look. The tires are brand new. The car was tracked a few times before I bought it.thanks again for all the insight, and please keep it coming, cause I'm just learning about vipers and any help is greatly appreciated.

 

[Vreracing]

Vipers seem to be a little more forgiving.

Every Porsche I've had, if one tire was just the least bit out of balance you could feel it.

I had a problem at 120mph in a 944T. I told the dealer and one time about 2 months later I overheard the service department people laughing about a car that was out of balance at 120 and how were they going to check that. Since I occaisionally track cars, it was a valid question.

My 16 year old had a party at my house about 6 months ago. This one 16 year old came up to me and told me he was the one who rebalanced my wheel. He said the first guy really blew it. He did a good job. It was just a little bit of a concern that an unsupervised 16 year old was the one doing the work.

I agree that a worn bushing can cause a vibration as well. If they're new tires I'd get them to rebalance them before doing a lot of mechanical work.

 

[Paolo Castellano]

Have you checked if the Vibration occurs in the same gear @ 70 MPH? Have you tried different gears? Does it vibrate in neutral(flat spots)? What about around a sweeper to the left? To the right(alignment)? It could be alignment, wheel weight balancing, driveshaft balancing, flat spots on the tires.......

 

[dave1123]

what is the right pressure for the Michelin sports? I know they have the ratings, but what is the best pressure for running on the street?

 

[SoCal Rebell]

It's always been tire balance on my car, first thing you should check.

 

[Jack B]

Either balance, lateral runnout (wheel) or a flat spot. I good tire-only facility should know immeadiately

 

[brianflynn]

Jack up the car and spin the tire you will be able to see a flat spot or if the tire is starting to seperate.