Slowly pushed my XK8 to up to 105mph.
At 100mph, I started to feel a slight wheel vibration that felt like a wheel imbalance. It was more of a vertical vibration, than a shimmy.
The tires are the PZero Pirelli's, and they have about 13,000k on them over the course of 10 years.

I found it odd that I would feel something at 100, and not 70-80

Let's talk tires

 

I'd have them re balanced, but would offer the following advice: Don't take tires over 7 years old above 100mph. Even good ones. The speed ratings are for new tires and each year past 2 years, take 10 mph off the speed rating.


If my car sits for 2 weeks, there is a vibration in the front end that goes away after a few heat cycles of driving. I would guess my front tires are 7 years old. New tires with a road force balance would likely fix this.


We open road race and its surprising how many low mile (but older age) tires come apart @ 130-140 mph. To run the 168 mph max tech speed classes, the tires have to be 2 years old or less. We had the tread come off a 3 year old tire after only 11 miles @ 160 mph (168 mph speed rated).

 

Thank you.
This is why I'm here

I'm thinking about changing tires anyway.
I'm looking for more comfort and year round / all season.

Currently have stock 17 rims.

 

I can´t make out what wheels you have by the photo, but if you have light weight BBS wheels you may have one or more wheels that are untrue.

I have Perseus 20" on my car and after I bought it I noticed the same vibration. Wheels were then all re balanced but still had the vibration. After a complete wheel refurbishment and re truing they were fine and looked as new.

I have read that these wheels do not handle pot holes well and will damage easily.

Good Luck.

 

The Sumitomo's on Tire Rack seem to be well liked and are bargain priced @ $100/each.

The Kumho Solus TA71 has even better reviews for only $15 more per tire.

Spending $250+ a tire for stickier Pirellis or Michelin's probably isn't worth it you want a all season tire.... and the available 700 tread wear tires are goofy on a sporty car unless you drive 15K miles/year... The tires will age out before they wear out.

 

When was the last time you or your mechanic had given the car a thorough once over on the bottom side?

If I wanted to go 100 mph in my jag, I would first get the car up on the rack and go over EVERY bushing, tie rod ends, sway bar links and bushings, motor mounts, etc. At that speed any little vibration or slop will be exaggerated. Even if there were no vibrations coming up through the steering wheel, I would still want to be 100% certain I had checked everything I could in the running gear.

 

The entire front and rear was inspected, and cured of any damaged bushings, mounts etc....
I ended up changing all shocks, mounts, and both tie rods. Ball joints were fine, as well as everything else under there.
Did an alignment of course.

The only culprit has to be tires. They're old PZero's

 

That's comforting. Glad you are on top of things. BTW my '97 front wheel bearings are smaller diameter than later models and I believe the MY 98 is too. Mine were wearing out every 30K miles. Check yours for wheel bearing slop. I ended up swapping front uprights with a 2000 so I could used the larger bearings.

Other than that it appears you have it covered. The only thing I didn't see is whether or not the wheels have been checked for runout and out of round. Good luck and be safe.

 

Bearings were fine upon inspection.

 

I wish I would have realized this when I did the bearings on mine. I would have sourced 2000 later hubs from the junkyard. This is a great tip if someone has a bearing going out.


I'll add this to the list of parts I'll snag from the junkyard if I ever run across one.

 

my 03 has a bent front rim, I don't feel it till I hit about 68 MPH.