Tyre/tire choices

[craig-ultima]

I've had my car (2004 Ultima GTR) on the road now for 12 months, including two full track days and 6000 miles of highway driving.

I damaged the rear tyres due to low pressure casued by a faulty pressure gauge that I only discovered after 6 months driving (a hammer and a glass covered gauge have never previously met with more energy, trust me). I also have had some rubbing on the front tyres on the headlight covers.

The track day I attended today was the last straw for my tyres. The rubbing got worse under heavy braking, down to the outer nylon wrapping around the tyres (i.e. cords are showing on the inside edge of the passenger side front tyre). And the fast cornering put the (already damaged) driver side rear tyre outside edge under pressure and wore it down to the nylon cord wrapping.

So, I have to replace all my tyres/tires.

I was running Goodyear Eagle F1 series tyres that I orginally got from the factory. They are the Fiorana sub-series that was developed for Ferrari (specifically the F-50). It seems like these specific tyres are no longer supplied.

I looked at the various tyres from Pirelli, Michelin and Goodyear that would fit the Ultima.

I'd really like to hear what everyone thinks about each, especially given its weight distribution.

[lvjost]

Hi craig. Wanted to give you a second opinion...I have my GTR on the street for 4 months now. Also equipped with the Ultimasports supplied Goodyears Eagle F1s... I´m very satisfied in terms of grip !!! But I was really "shocked" to notice, that (with my driving style) they won´t really last much more than 3000 miles..because from originally 6.5.mm profile is just 1.5 mm left and I got 2240 miles on my speedometer...So I think about changing to the ones Sven (schimms -the first GTR in Germany) has got, because he already has 4000 miles on his GTR and his first set of tires with a good bit of profile left... I know, an owner of a GTR should not worry about fuel prices and tires...but 3000 miles for a set of rear tires, 600 Euro each in germany is kind of hard to take...Please let me know, which tires you(´ll) finally have bought and giove me a short critic for them....

[m3desmo]

lvjost said:

Hi craig. Wanted to give you a second opinion...I have my GTR on the street for 4 months now. Also equipped with the Ultimasports supplied Goodyears Eagle F1s... I´m very satisfied in terms of grip !!! But I was really "shocked" to notice, that (with my driving style) they won´t really last much more than 3000 miles..because from originally 6.5.mm profile is just 1.5 mm left and I got 2240 miles on my speedometer...So I think about changing to the ones Sven (schimms -the first GTR in Germany) has got, because he already has 4000 miles on his GTR and his first set of tires with a good bit of profile left... I know, an owner of a GTR should not worry about fuel prices and tires...but 3000 miles for a set of rear tires, 600 Euro each in germany is kind of hard to take...Please let me know, which tires you(´ll) finally have bought and giove me a short critic for them....

As Sven suggested, that may have something to do with your trembling right foot!!

[mogg]

I currently have Pirelli P Zeros (on the car when I bought it). I'm not overly impressed with the grip, particularly on track. Apparently the only road legal track tyre wide enough for the rears is the Kuhmo V70A. These are what I will be fitting next year. Anyone tried them on track ?

[thevet]

I've got the medium compound front and back and I reckon they are great for grip in the dry. Didn't like them at all in the wet, but I've done nearly 2k on them mostly on track days and still reckon to have some good wear out of them yet. They are not expensive IMHO either

[B1 ECC]

i've been running V70's for the past two years, far and away superior to the pirelli's, good-years seem to be o.k. but expensive!!
Dry grip is excellent, wet grip is very good when tyres have little wear, did Spa this year in the pouring rain and the car was surprisingly good!

[gtr-tt]

B1 ECC said:

i've been running V70's for the past two years, far and away superior to the pirelli's, good-years seem to be o.k. but expensive!!
Dry grip is excellent, wet grip is very good when tyres have little wear, did Spa this year in the pouring rain and the car was surprisingly good!

I'm using Michelins, 335 rear and 255 front. They work very good on road but over heat on track. Wear seams to be good on road but they totally burns up on the track. I think I will try to fit something like 275 in front to get better balance.

I need R tires... Do the Kumhos hold for 15+ laps in high speed?

[therighthand]

I have seen Yokohama A048's in 335. However, the site I went to(tirerack.com) no longer has them.

For a good street tire the Michelin PS is always a good recommendation. Doesn't wear as fast as the Pirelli's and has excellent grip.

[Puppetmaster]

Can somebody tell me what the height of the tyres need to be? And can you also tell me what the measurements of the wheels are (offset and such).

[gtrclive]

125mm from the hub face to the outer part of the rim front and rear wheels.
9" front wheels I think have Zero ET.
12.5" to 13" rear wheels
Just make sure you have at least 25mm Caliper clearance as well...

[Chewy]

Following good info from B1ECC I started using the Kumhos for racing. I qualified on the standard factory Goodyears and then changed to the Kuhmos for the race so had a good back to back comparison. The grip level was remarkably better with the Kumho. They felt very predictable and the breakaway was progressive. The wear rate however when pushed hard is also significantly higher. The Kumhos are effectively a shaved tyre so tread depth is very shallow from new so combined with heavy use the lifespan is significantly lower. I have never used them in the wet but would expect them to be quite good in light to moderate conditions due to the soft compound but would be a little worried if there was standing water due to the pattern and tread depth. The biggest problem you will have at the moment is getting your hands on the rear 335s as there have not been any supplies to the UK in the last six months. Kuhmo had to fly me a set in from Germany so I could continue to race with them.
Yokohama A048 are a class 1B tyre as are the Kumho so I would expect similar performance although the tread depth is deeper. However the largest tyre size is 315 which Yokohama specify maximum rim width of 11.5 inches which would not therefore fit the factory standard rims. (I had set of Rims reduced to accept these but never used them)

[gtr-tt]

Good info Chewy, Thanks. Kumho can also supply slicks in the right dimensions.

[Chewy]

gtr-tt

You are correct in saying that Kumho do a slick in the right dimension.
However I spoke with Kumho-UK last-week and they do not stock tyres to fit the Ultima rears as they have never had the demand for them.
I have looked at several options and could not find a Road/Track tyre that will potentially deliver the performance of the Kumho which is one of the reasons I had the rear rims reduced to accept the Yokohama. For next year I am looking at events where I can run slicks with the most likely option being Dunlop but alas that means the car will be no longer be used on the road.

[therighthand]

Thanks for the info on the Yok'smust have been my mind playing tricks. Looked in the catalogue and effectively they do not supply any larger than 315.

Also I have noticed that Nitto makes the NT555 Drag radial in the appropriate size. I don't know if anyone has tried these. A little less extreme than the Yoks and Kumhos.

[harshman]

I have them and they are great. very sticky. when i build my ultima nitto they will be.

[Chewy]

Nitto sound like a good prospect for track use. I have never heard of them but looking at there web site it appears the best match would be the "NT 555 R".
I personally would have no reservations about fitting them to the 13 inch wide rear Ultima rims but it does say the approved maximum rim size is 12.5 inches. I think I would want written confirmation from them to say 13 inch rims are suitable for road use if only to ensure in the unlikely event of problems that the insurance company do not use it as a loop hole for avoiding their obligations.

[gtr-tt]

Hoosier also provides two different "R-tires" 335/30-18

A6 = Autocross
R6 = Roadrace

www.tirerack.com/tires/tires.jsp?tireMake=Hoosier&tireModel=R6

Hoosier sounds very "drag racing" to me... Anyone tested them??

[gtr-tt]

Got a mail from Michelin today where they say that they will have a 330/650 slicks available soon.

[gtr-tt]

Chewy said:

gtr-tt

You are correct in saying that Kumho do a slick in the right dimension.
However I spoke with Kumho-UK last-week and they do not stock tyres to fit the Ultima rears as they have never had the demand for them.
I have looked at several options and could not find a Road/Track tyre that will potentially deliver the performance of the Kumho which is one of the reasons I had the rear rims reduced to accept the Yokohama. For next year I am looking at events where I can run slicks with the most likely option being Dunlop but alas that means the car will be no longer be used on the road.

Kumho in Sweden said that they use them for Ferrari Challenge and that they can deliver. This was two month back in time though...

[therighthand]

Actually Hoosier is pretty big on SCCA level racers, so autocross and some comp. But yes they are still pretty big in drag racing vis-a-vis other places. Still Hoosiers are cheaper than many of the big brand race tires so I guess thats a reason alot of people go to them.