spider shimmers between 40 & 55 mph

juanspider · #1 (**permalink**) 09-19-2006, 08:35 PM

Just bought an 86 spider and it shimmys a bit somewhere between 40 & 55 mph, shocks are good, arms are firm, any ideas please.? thanks

redalfalvr · #2 (**permalink**) 09-20-2006, 06:34 PM

Ball joints? Tie rod ends? Wheel bearings? Wheel balance? Guibo?

**papajam** · #3 (**permalink**) 09-20-2006, 06:57 PM

Welcome to the Board!

Does the shimmy occur if coasting in neutral at those speeds? Accelerating/decelerating? Does the steering wheel shake?

**ghnl** · #4 (**permalink**) 09-20-2006, 08:26 PM

Swapping tires front to rear, rear to front might help you decide if it is a wheel imbalance or tire out of round.

Also, some types of tires are prone to flat spotting. When the car is parked for a while the contact patch can take a set. Usually, driving the car for a few miles warms them up and the flat spot will become round again.

http://www.digest.net/alfa/FAQ/164/p164_13.htm

Worse case would be tread seperation. Look carefully & feel for lumps or bumps !! caution !! sometimes a steel thread (from a steel belt) will protrude through the rubber. It can easily cut your hand.

juanspider · #5 (**permalink**) 09-21-2006, 07:54 PM

Thanks all for your response:
papajam: The steering wheel does not shake.
I will have to check if it happens in neutral.
It does happen while accelerating.
Will check while decelerating.
redalfalvr: Tie rod ends and ball joints are tight.
GHNL: I've put some 45 miles on her so if that doesnt get rid of the flats well..then the steering wheel does not shake so I can discard imbalance.
Out of round hmm maybe, will check this weekend since I'm having her aligned.
I bought the car last weekend.
Let me add to the description of shimmer, this feels like the car moves side to side very slightly and goes away over 60.

**ghnl** · #6 (**permalink**) 09-22-2006, 07:38 AM

If the car sat for quite a while before you bought it (& began driving it) it could take more than 45 miles to see if the tires will become round again. Especially if it sat with soft (low air pressure/flat) tires. Some types of tire construction are more prone to flat spotting than others (i.e. nylon vs polyester or whatever).

What tires pressures are you using? Try a few more PSI and see if it makes any difference.

**ghnl** · #7 (**permalink**) 09-22-2006, 07:49 AM

One other thought. I bought a basket-case Spider but had never driven an Alfa before. After getting it back together (with new tires carefully balanced) I knew something just wasn't right with the way it rode & steered.

Here's what I found: First the DPO (d*mn previous owner) had set the Koni shock absorbers to their firmest settings. Putting them all to the next to softest setting made a big difference.

However, despite a careful front end alignment (I highly reccomend Digital Chassis in Durham, NC - Brad is a perfectionist who takes the time to get the adjustments spot on) it still would wander. I finally discovered that the steering idler shaft was not moving freely. I swapped in a spare and it was like a different car. The old idler could barely be moved with two hands, the new one was smooth and moved with finger pressure. That tight idler prevented the front end from self-steering despite correct caster.

lorencew · #8 (**permalink**) 09-23-2009, 12:15 AM

My steering wheel did shake back and forth when I reached a certain speed.

This was likely from tires sitting and low air pressure.

I drove it a few days later. It was cured.

**conedriver** · #9 (**permalink**) 09-23-2009, 05:26 AM

Sometimes (rarely) a belt will shift on a radial tire. I had this occur many years ago. If the tire is on the front, the steering wheel will shake or vibrate. If on the rear, the back end of the car will wiggle. As suggested earlier, switching tires front to rear may assist with your diagnosis.

Quote:

Originally Posted by juanspider

Just bought an 86 spider and it shimmys a bit somewhere between 40 & 55 mph, shocks are good, arms are firm, any ideas please.? thanks