Sooo, the '08 XKR I bought last week went to the shop where they checked it over and balanced the front wheels. The vibrations are MUCH reduced, but there is still something there on certain asphalt surfaces. The tech seems to think it is the REAR tyres as they are getting towards the end of their life. They are the Dunlop OEM fitment which according to my research on Tirerack, gets mixed reviews at best. Should I just bite the bullet and get a set of Hankooks to match the front?

Interesting suggestion from the dealer on fitting new tyres. He says to have an alignment done at the same time. I think he is looking for work, what do you guys think.

The check engine light is off and the sheet says "Reconfigured engine control module using DVD127 Patch7". Any clues what that lot means.

TIA

 

Front end vibrations generally make themselves felt in a steering wheel vibration. So, if you have a calm steering wheel but, still some vibration, it could well be the rear tires.

Also, do note that these ultra low tire sidewalls on the XKR are very stiff and do pick up vibrations on various surfaces more than the older tires sizes with more sidewall rubber to dampen the ride.

The dealer ALWAYS seem to recommend an alignment. Too bad that most of the people have no means of telling if one is needed or not, other than looking at tire wear. The rear wheels have no built-in camber adjustment so, if shimming is needed that could get expensive at the dealer. I use a set of very simple brackets that I built back in my racing days to check my wheel alignments in about 10 minutes total.



Albert

 

I wasn't going to put Dunlops back on because of the poor wear and noise. Based on research, I decided on Continental Extreme Contact DWS.

Unfortunately, they were back ordered everywhere so I settled on the Hankooks. They get some good reviews and seem to be pretty popular around here. The price is right, much cheaper than the Dunlops! I'm happy with them so far but I'd still like to try the Continentals.

The tire wear patterns on your current tires should indicate whether an alignment is necessary or not. Check for even wear. Its false economy to skip it if it will prolong the life of the new rubber.

"DVD127 Patch7" sounds like a software update to me.

 

Axr6 is right that you can feel front wheel balance problems by small vibrations in the steering wheel on smooth roads when you are driving at a constant speed.

I can tell from that if a wheel is out as little as a quarter of an ounce.

I always stand behind the shoulder of the wheel tech and make sure they are getting zero zero balance on every tire.

Too often they are in a hurry and will let a wheel go with a quarter or even half an ounce out on the balance on the theory that most folks will never notice. Problem is that it starts out small but gets bigger the longer you drive it that way.

You can also tell if it is the rear wheels usually by putting your hand on the transmission hump of the car behind the front seat and if you feel a vibration there it is the usually the rear wheels. (Leaving aside drive shaft issues).

From unhappy experience when I was young I can tell you that front end alignments are always far cheaper than replacing tires from uneven alignment wear.

That goes double for four wheel drives always get the rears checked as well.

Cheap tire insurance if you will....always get it.

The dealer is actually trying to save you money in the long run and it was good advice.

And yes you can tell if a car needs it by tire wear but by the time you can see that it is usually too late to save those tires you are in effect just looking at the past.

An alignment check can see into the future before you have problems and avoid them.

Besides any serious pot hole or curb bump can put the alignment out of perfect 'true' and you don't know how the guy before you drove or what they hit.

Enjoy your 'new' car and post some pics for us.

cheers,

jj

 

I took the car to the local tyre shop and had them check the balance of the rear wheel. The tech said they are bang on, However, he did say that the Dunlops have cupped a bit and it is a known issue as they get towards the end of their life.

Also, he told me that the tread compound is layered so that you are driving on progressively harder rubber as the tyres wear. He said that if the vibration was slight then not to worry as I had enough meat left on the tread to be legal and safe.

As for replacement tyres, he reckons the Hankook or Sumitomo summer tyres are great value. He says that Michelins have issues here due to the summer heat and that Pirellis can be rather noisy. He also said point blank that the price of Michelins, Dunlops and the other "top" brands were simply ridiculous as they offered little or no advantage over the likes of Hankook, Yokohama or the other "better" Japanese makes. Have I found the one honest tyre tech in Las Vegas? I can live with that thought.

Jamjax, you brought up the drive shaft. Is that a known weakness or were you just mentioning it as an example?

TIA

 

Orange;

Cupping will do that....even tires that have been just sitting too long without driving can become impossible to balance the 'flat spot' out.

No issue with drive shafts that I know of, that was just an example, as a one week owner I am not the guy to ask.....when there are so many real experts on the forum.

I did extensive research on XKR's and moved up the production dates from 2000 to '03-'04 with the 4.2 engine and sixth speed transmission, to avoid the three major issues of Nikasil cylinder liner degradation, plastic timing chain tensioners that imploded engines, and the Mercedes Benz five speed auto that liked to put itself in reverse when you were going down the highway.

Plus I just like the design better at that point than the '05 flush grill....though I think I am going to remove the two little teeth/fangs in the grill.

Your tire/wheel Tech sounds good.

Check out Tire Rack reviews there are plenty of great tires out there besides the legacy brands.

Tire Research : Tire Reviews and Ratings

Here is a link specific to XKR's:

http://www.tirerack.com/survey/Surve...ents=Y&index=0

They have millions of user miles to rate tires and Consumer Reports is a good place to start as well.

I have been a life long Michelin guy but I had a lot of trouble with the last set of All Season Pilot Sports on the Volvo and started hearing from tire guys that they had problems with them....don't even get me started on how insanely expensive tires are in Europe and it is nearly impossible to get all season tires....they are firmly in the you have to have a winter and summer set.

Some countries will write you up for not having winter tires and even void insurance coverage if you are driving on the wrong tires and have an accident.

Plus they don't do Wear Ratings because no kidding you see guys bragging 'oh I got 20,000kms out of mine they were great.'

So you are lucky to 15,000 miles out of a set of European tires

I used to get 125,000 miles out of Michelins.

I am running a set of Falkens, part of Sumitomo and Dunlop, on the Mini, they aren't as razor sharp as the Potenza's we had on it but they also don't shake your fillings out on every little imperfection on the road.

Hated the OEM Potenza's run flat tires...harshest ride you can inflict on yourself for a 5% gain in overall performance.


cheers,

jj

 

I never heard the layering of different compounds but, may very well be true. What is definitely true is that tires age. The rubber compounds are impregnated with chemicals that keep them soft and pliant. Due to simple aging and also to "heat cycling" (the number of times a tire heats up and cools off) those chemicals evaporate leaving the thread compound hard and brittle, with the tire loosing much of its ability to stick to the pavement. Harsh ride is VERY typical with older tires. Have you noticed just about every time when you get new tires that the ride feels nicer and more compliant? That is the difference in old and new compounds.

At times I had to get rid of expensive sets of tires that had nearly all of their thread depth but, were sitting for years with extremely low driven mileages. The rubber aged anyways and the tires were next to useless for any kind of performance driving.

Albert

 

i got yokohama avid envigors. low price,high treadwear rating-560. not noisy.

 

For sure it's good to do an alignment when replacing tires and most tire places will do a free alignment on 4 tire purchase. I like to sit in the car while they do the alignment as the car will be better balanced unless they "sand bag" the front seat which is hardly the case.

I was suprised when replacing tires on my VDP how dead on the alignment was considering the crappy Boston roads