Well, it's not really new it just feels like it. My 2006 XKR just got new tires and a 4 wheel alignment and it feels the best it ever has. The car had Continental tires on it when I first bought it, and they were replaced with Nitto Invos at about 38,000 miles. During the last month the car has been vibrating something awful above 60 MPH, and the tires were about shot, at 54,900 miles. I ordered Sumitomo HTR Z III tires from Tirerack.com and had them delivered to Tech Plus Automotive in Scottsdale, Arizona. Tech Plus did a great job with a 4 wheel alignment, and road force balancing. When I drove away from the shop it was immediately apparent that it was like driving a new car. I'm really happy that I made a good choice on the new tires, and that I found a top quality shop to take car of my favorite car.

 

Hey, those are the tires I'm putting on my xk8 or xj, whichever one wears out there shoes first! I'm glad you like em, in about 5k, please update your thread with a follow up review.

 

The reason I chose Sumitomo HTRs is I had a bit of help from a good friend who used to race Porsches at Daytona and Watkins Glen. After I had read every tire review and watched every video on TireRack.com I had settled on two brands and was vacillating between all season tires or summer tires. When my friend said I should definitely choose the summer tires that's when my decision was finalized. Here in Arizona I never have to drive in snow, and seldom is the temperature around freezing. The car never goes out of the garage if it's raining either, but that very seldom here. I'll give an update on the tires after I put more miles on them. 5000 miles would take me until next summer though, so I'll make a report earlier than that.

 

Good to hear from a fellow Arizonan! I am looking at replacing my tires soon. Good to know you like the Sumitomos.

 

December 21st and the Mayans were wrong. We're still all here and I'm still enjoying my car with the new tires on it. I only put 544 miles on the tires so far but I'm totally pleased. The Sumitomos ride smooth and quiet, and they have plenty of grip even when it's a bit cold. This morning it was 38 degrees when I went out so it wasn't very cold compared to most parts of the country. The biggest surprise is the car no longer has a vibration around 70 mph. On the freeway it rides as smooth as glass providing the road surface is smooth too. When I get a chance I'll see how smooth things are over 100mph and do another followup. So far I think I made an excellent choice.

 

I have the 70mph shudder and will be in the market before spring. Thanks for the info and looking forward to update at higher speeds...which will undoubtedly come from a friend who used your car and allegedly went faster than posted speed limits!

 

Interesting to hear that your vibration was cured by changing tyres. Several people have told me that could be the cause of the vibration I am getting between 65 and 75 mph.

 

These low-profile large-diameter tires simply have no margin for error. If they aren't built damn-near perfect coming off the factory line, it doesn't take much to send them out-of-round. Hunter Road Force Balancing can overcome some of these issues but not all of them. If your tires have not been through this balancing process and are giving you trouble, you might want to try it before deciding to scrap them....

 

My experience with the Hunter Road Force Balancer:

1) The ballancer has probes to indicate physical runout problems with the rims that show if the Wheel is bent or mis-shapen. If the Wheel is out of spec, Balance is not possible.

2) If the Wheel is in spec, the ballancer may or may not be able to find a combination of Wheel and Tire Positioning that will compensate for a poor Tire.

3) In my case, 2 of 4 wheels had to be sent out for repair with satisfactory results.

4) The XKs are VERY sensitive to Wheel Runout (Radial or Axial). The Wheel must be almost perfect to avoid vibrations even with excellent tires.

 

Ditto what Paul said. My old 05 XJR had 2 bent wheels that the Hunter machine discovered. Fortunately the problem was not so bad and a road side wheel service vendor fixed them for $70/75 each. It may have been $175--I forget.

The last time I got tires for my 07 XK the lowest price was $200 under from a dealer who did not have a Hunter machine. In order to clench the sale he told me If he could not bal the tires to my satisfaction he would pay for a RF bal and/or return the tires for good ones. Luckily for us both the tires balanced were more than satisfactorily on his machine. Go Continental.

 

My new tires now have over 1000 miles and they are fabulous. I just found out that they run smoothly all the way up to 140 mph. Of course I wasn't driving the car when it was going that fast. I think I left my garage door unlocked and someone took the car for a spin. Good thing they left a thank you note and told me about the speed.

 

Frank - if you don't my asking, what did the sumi htr's cost? Installation?
Thanks and see you on the 101

 

I am not trying to rain on anyone here, I have no doubt you and many many others have had great experiences with the HTR's. I had a different experience however. I had Toyo tires on my car when I bought it. Car was smooth at highway speeds, no vibration. They were fairly worn though, so I had the HTR's fitted on a "buy one get one free" sale, so had 4 for the price of 2. Great deal. But immediately went back to have them rebalance due to vibration on the highway: slight improvement. Went back again, rebalanced, no improvement. Went to a Goodyear shop that had a hunter road force machine, they said one of the fronts was too far out of spec to do anything with, and another (from the rear) was close but they could compensate. So I went back to tire place i bought them at and they replaced the one tire that was way out, without question. Still had vibration at 68-75 on highway. Went to Goodyear again for road force on the single new tire. Drove for about 9 months to a year but still had the vibration on the highway, but I don't drive the highway often, or I should say, for long stretches, occasionally I will do a longish 4 hour one way trip, but most of my driving is around town. Finally went back to Goodyear for another road force, which they did, still not satisfied, no improvement - same highway vibration. So i bit the bullet and bought 4 new Goodyear Eagle F1 Asymetric's. This is a different car now. The ride is much improved, smoother over the bumps etc, and the vibrations on the highway are gone. What is also interesting is that I never really noticed a vibration also at about 30+ mph...with the new tires, on a smooth road, the car is glass smooth, but never was before. I guess I hadn't realized it, or maybe I did a little bit but just thought it was normal. It was a lower frequency vibration, that would go away and smooth out as I sped up, and then I had the 68-75 vibration. I think the vibration at roughly 70 mph was a harmonic of the vibration i felt at about 30ish mph. Anyhow, I can't say my experience is typical. I am sure Summitomo's are good, but this was my experience.

 

The 4 tires from Tire Rack cost $695.64 delivered to the shop in Scottsdale.
Tech Plus charged $107.80 to install and road force balance them.
I also had Tech Plus do a 4 wheel alignment which cost $169.95
So the total was $973.39
It's a lot of money but I got a new car out of it.

 

I have used the HTR's for years and they are as good as anything out there at a lower price. The performance is top rate. When I got the XKR in 09, it had new Michelin Pilot AS's on it. They began shedding tread at an alarming rate and vibrating so I trashed them and put on the HTR's. Worked like a car should then. The HTRs are a real summer tire, so don't even try snow or ice, or even temps below 40F. The tread life is pretty good, getting around 30-35K miles out of them.