Deb

My 84' 928s gets very little road time - approx. 700 miles per year - and only on dry pavement and good roads. Shortly after R & R the motor mounts I noticed a mild thumping/vibration noise at any MPH over 40, the steering wheel doesn't vibrate nor does the car wander from a steering perspective. This tire wear is on all 4 tires and I'm at a point of hauling the Sharkster to a alignment/shock shop -Porsche dealer- for a diagnosis and correction.
The wear seems to be more like that caused by worn shocks but only time and $$ will tell.
Does any one have any recommendations re: choice of shocks given that this car isn't exactly a high mileage hauler and I don't plan on screamin' arounf a track?

Mike LaBranche

I'd stuff the stock Boges back in there. They're fairly cheap, give a decent ride, readily available, match the springs per the manufacturer. Street/highway driving they're just fine. Not doubt your shocks are tired, most are. But, uneven tire wear is usually alignment. You could also bump that mileage per year an order of magnitude. You could be feeling flatspots.... just kidding. Could just be this set of tires.

Garth S

Actually, Mike touched a good point on the tires: with the low annual milage,
- how old are the tires?
- what ambient temps ? - ie., are you talking about winter driving ? - on 'Z' rated tires?
- Are the drives long enough to get tires up to temp?

Having removed a known vibration source by replacing motor mounts, perhaps this issue is one that was preexisting - and is now claiming #1 spot!
As far as uneven wear, do check the suspension heights ( ~170mm/corner on the machined pads) - and follow with the alignment. Agreed with Mike that while the shocks may be getting tired, they would not be my first guess as being responsible gof uneven tire wear - especially considering the driving style mentioned on smooth roads. ( how come you don't have potholes like the rest of us taxpayers?? )

Green Goblin

If you see cupping on the sides of the tread that usually means that the shocks are toast.

Good luck
Andy

Deb

Garth, the tires are about 6 yrs old and mucho tread left. I live in a rural area so all road time is highway and I'm sure that the tires get warmed up. no winter driving. No potholes because (a) THE road is the highway that runs about 50 K's around the island and has a traffic load of about 4 cars per hour except in tourist season when the winery tours draw in more traffic; (b) when you have a road maintenance crew that has one highway to maintain they tend to hand manicure it to maintain job security.
I will flatbed her to Ottawa or To. as soon as the weather breaks and see what has to be done, also have 4 new Kumho Ecsta tires to mount once the alignment/shock issue is solved.

Deb

Green Goblin, yep, that is my understanding as well but I took it into a Goodyear dealer to price tires and he felt that there was no issue with the shocks. I also checked the wheels for any wheel bearing/other wear and the wheels are solid.