Dolfan

OK, need a new set of tires for this season. I've been running V710's and I think I will continue to do this, they give me and my co-driver good wear through the season, maybe a bit better than Hoosier will.

The real question is 275 or 295 up front?

I've just upgrade the front with a larger, 32mm bar, and fresh Koni adjustables to replace a leaking one, so that is the front set up for a car is SS class.

What are the pro's and con's of moving up to the 295?

TedDBere

When Kumhos were the tire of choice (before the Hoosier A6s were released) the size of choice on the fronts were the 275s.

Problem with Kumhos were two fold: Firstly they lost their good grip at about 40 runs, and they got greasey when they got hot. You never saw a water bottle in a national grid until the 710s arrived on the scene.

As a positive the 710s last forever, but not the competitiveness of them which is why you'll never see them on a nationally competitive car that doesn't have a paid Kumho driver using them. The A6s improved their wearabiliy over the older Hoosiers and if you flip them between 50 to 60 runs it's not uncommon to get over 120 runs in a well set up car which is about what you'll get out of the 710s. The difference being the Hoosiers will remain competitive thoughout much of their lives.

The last time I corded my A6s Salerno jumped in my car and beat his times in his usual ride...despite the corded tires, fwiw.

Dolfan

TedDBere, good points I agree the Hoosiers are quicker. What you are telling me is that is setup is good and flipping at 50-60 runs I should get similar wear. I guess the other question then is still the same as with the Kumho, what are the thoughts on the front width?

TedDBere

The top C5Z06s run the 295 A6 up front. I believe the 710 295 is taller and therefore less crisp at turn in than the 710 275s were, hence the preference for the 275s when you are using Kumhos. The 295 A6 diameter is similar the the 275 Kumho and therefore you get more grip and crisp turn-in with them on the front of a C5Z. There may have been some rubbing issues with the 295 Kumhos on the front, but it's been a while since they were the "hot" tire so I may be remembering wrong...but all the C5Z Kumho users back around 2004/2005 were definately on the 275s in the front. Tire pressures were way lower too, about 4-6 lbs lower, iirc.

Solofast

Agree with all of the above, but I never got 120 runs on a set of hoser's.. More like 60 and the outsides were corded, and by then they were heat cycled enough that they weren't that good until they got hot. Not as bad as 710's, but not nearly as as good a fresh tires.

But you are right, the 710 got heat cycled and were worthless at 60 runs. Maybe if you dope them you could get more, but they didn't respond to Formula V as well as some other tires have. Maybe a different dope would work better. Just never tired anything but FV..

710's did work OK if you got them really hot when they were older. That is, you could use them at a test session and get them hot and the results were still pretty honest. You just had to get two or three consectuive runs on them to get the back tires toasty and then you would have decent grip and repeatable results. If they weren't hot enough you'd just be chasing the setup around bad tires.

If you use the Kumo 295 in the front the clearance is getting pretty tight.

The 295's weren't any faster than the 275's, and they felt more "rubbery", and didn't feel as crisp on turn in.

You can't use spacers or the legal 1/4 inch of additional offset in the front with either 295 tire, you'll hit the inside lip off of the front fender...

Dolfan

OK, so it sounds like you are saying the the Hoosier A6 295-F/315-R would be the best combination, but if I stayed with Kumho to go 275-F/315-R setup. That is what I'm reading here.

talon95

Yep, I agree with this also.

My personal experience is about the same. 710's cycle out around 50 runs (fall off a cliff). They last a lot longer in part due to this. I didn't like the 295 front for 710's either.

My experience with the A6's is different also. I find they start falling off significantly in the 50-60 run range. Not nearly as bad as the 710's though. I usually get around 80 runs before chording.

The number of runs you get is very dependent on usage. As far as runs to chord, this is very surface dependent. If you run on a lot of tire friendly asphalt surfaces, you may get closer to 100 runs. OTOH, if you run on more abrasive surfaces, it's going to be more like 60-80. This also depends on driving as well of course.

I've also found the number of competitive runs you get from A6's depends on temperatures they see. i.e. overheat them one or more times and they cycle out a lot sooner.

Both of these last 2 things I think contribute to the rather wide range of comments you get. Bottom line, proper care of the tires can extend their life significantly.

Dave G.

Dolfan

Great info guys, thanks.

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