BS rubber: v710 vs. A6 (245/35-18)
 

hi guys,

i'm moving to BS from STU and would love it if a few gray areas re: the v710 and A6 could be cleared up. i've searched and this is what i've found:

v710: cheaper ($271 vs. $282), stiffer side wall, lasts longer (fades/die from heat cycles before cording)

A6: 2 lbs. lighter and 0.4" shorter, better longitudinal performance (acceleration/braking), better in colder temps, wears faster

is this about right? i've also read in the archives that all things considered the tires are mostly equal and it comes down to driving style.

where did you come up with 0.4" shorter? :dunno:

tirerack: v710 vs. A6

I think he is comparing the 245 Hoosier. Mistake. 245 kuhmo vs 285 Hoosier or 275 Hoosier. Some super tire mounters can get the 285 kuhmo mounted, but not mere mortals. Note Isley has won his national championships on 245 kuhmos.

yes, i'm comparing the 245/35-18 of the v710 and A6. i updated the thread title to be more accurate.

why is comparing the same size a mistake? because the A6 is cantilevered?

i think everyone knows the v710 is the BS tire of choice and has been for a long time. i'm just asking why not the A6 in a 245/35-18. :)

V710 vs A6 are very, very close on the RX8.

I had the opportunity to test the 285 A6 vs the 245 V710 last year for a Grassroots Motorsports tire test article. (GRM Nov 07) Teaser Video Here: http://www.tirerack.com/videos/index.jsp?video=6

The 285 A6 generates more lateral grip around the sweepers and launches a little better than the 245 V710. The V710 communicates better at the limit and recovers from overdriving more quickly. The shorter OD also helps the V710 pull off slower corners. My personal opinion is, the V710's ability to communicate and recover at the limit gives most drivers a little more confidence in their car placement when running through fast transitions/slaloms. This additional driver confidence offsets the Hoosiers grip advantage.

I have not tested the 245 A6 or the 285 V710 yet. My semi-educated guess is all four options would be within 2-3 tenths with course design and driver preference shuffling the actual finishing order.

Chris Harvey

Early RX-8 driver here tried 245, 275, 285 Hoosiers. His opinion was the 245 Hoosier wasn't enough tire, they overheated easily. The 285's were slightly faster on sweepers but were worse in transitions and turn in than the 275's.

The A6 Hoosiers look to be just as fast as the Kuhmo's based on the overall results last year. The Kuhmos last longer and most feel they are more forgiving. The Hoosiers have a razor sharp feel and reward precise drivers. When it comes down to it the Hoosiers and Kuhmos are well matched (at least when new).

EDJ has been one of the quickest Hoosier guys all along, he is on the 245.

lol, always go to the source for accurate data

https://www.hoosiertire.com/specrr.htm

only 0.1" in diameter delta, you have to divide by 2 for the radius which is the number that counts, so less than 1/16" shorter difference

Beat me to it...

Chris said it all, above...it just comes down to what you want to run and where you think the contingency is best ;)

I still say 295 is the way to go with HooHoos ...

my ears are burning... :)

The V710 and A6 245s are in a virtual dead heat. For most people, the V710s
are a better deal because they last longer and hold on to their grip better later in life.

I have 70 runs on my current A6s and they will be toast after my next event.
I and plenty of other people have gotten over 100 runs on the V710s.

This is on the 245s only. I won't get into the 275/285 debate as I haven't used
those sizes in the current tire models.

ymmv.

Welcome to BS gang Doug! Hope to see you at the the National!

After experimenting with 245 A6/V710/Z214(C70), I would say get V710, knowing that Philly SCCA have more runs per event basis than other regions. Price consideration was the major factor for trying C70 for us.

hey steve, thanks for the info. a recent development may see me co-drive in a shenefield prepped STS civic so we'll see if i do the STU -> BS swaparoo after all. quite a dilemma.

I am very surprised to hear that the 245 H keeps up with the 245 K.
We tried the 245-40? H on the Solstice and they couldn't beat OLD 245 K's.
Oh! They corded WAY too soon on the fronts on asphalt. And that was with 2.5 neg camber and 7 degrees caster.:rant:

BUT! Alan Dahl ran the 295H on his Solstice ZOK-GXP(also 8" rims) and FINALLY straight timed us CS'ers this last weekend.
His tires were new and were leaving long dark black marks all over the course. I suspect he will need new tires after Cali.
:shocking:

FM

edj, typically how much higher pressures do you have to go up to run the 245 Ho-Ho's? Did you have to make any major set-up changes between the two 245 tires?

These are the specs for the 245 V710 & A6 per the Tire Rack:

Kumho V710Size: 245/35ZR18
Tread depth: 4/32"
Weight: 23 lbs. 8-9.5"
Rim width range: 8-9.5"
Measured rim width: 8.5"
Section width: 9.8"
Overal Diameter: 24.8"

Hoosier A6
Size: 245/35ZR18
Tread depth: 4/32"
Weight: 21 lbs.
Rim width range: 8-9.5"
Measured rim width: 8.5"
Section width: 9.8"
Overal Diameter: 24.7"

If Kumho doesn't get their act together soon, my co-driver and I may go with the 245 A6 for Nats - it's 2lbs lighter per tire, and will provide a slight gearing improvement over the V710. I'm not a big fan of squishy sidewalls, so we'll probably stay clear of the 285/295 A6's! :lol2:

-Chike

Chike,

I actually run less pressure with the Hoosiers than with the Kumhos. ;)
But I have a stiffer front bar than most people so that helps. I would
suggest you start with the Kumho pressures and work from there.

oh, and no other setup changes switching between H & K tires.

Thanks! The Kumhos will still be our first choice, but by the end of July we need to secure our tires for Nats. I know some have mentioned the 245 A6's overheat more easily, but I'm not too worried given the 'cooler' September temps in Topeka.

If we do run the Hoosiers, we'll go with our current Kumho set-up and adjust as needed.

-Chike

the outside corners on my 295s look great after 50+ runs on both asphalt and concrete surfaces

the grip went off this past weekend, but they haven't been flipped yet either

I'd say the grip only fell off on the fronts, which were starting to round off a bit towards the sidewall (too bad, I think we had another half second, or so, to get). Flip those bad boys on the rim and they should be good for a bit longer.

Eric, are you sticking with the 245's? You might want to try the 295...I've only driven on them twice, but am impressed:)

i'm waiting for Baghead to beat somebody on them first... :spank:

apparently you forgot that those were the rears and the car was loose in the AM session before I swapped them to the front for the afternoon session when you drove :eyetwitch , they also didn't round off until you ran the dog sh-t out of them with the car pushing :) when the car understeers I don't just crank in the steering wheel and aim for the inside, I let up on the throttle ... the differences showed, both in times and tire wear ...


you might be waiting a while then, I'm much better at setting up cars than knocking down other drivers

No, I didn't forget that you had swapped them from the rear, I just didn't mention it...sorry if I added to the wear of the tires, I only adopted the "aim for the inside of the cone" technique on the last run, but I wasn't cranking in steering lock as much as I was just setting up way early and letting the car push off to the apex. I'm usually really easy on tires (a byproduct of being not so fast, doncha know)...I really hope I didn't pixx you off by contributing too much to the wear, I enjoy driving your RX8 and appreciate your letting me take laps in it :)

I am driving on 245/35 Hoosiers right now, and I cannot believe how much slower they seem than the 285's. I think the 285's are much more forgiving of crappy driving like mine.

I would be a little worried about the gearing disadvantage of the 295's, but at Heartland, it might be okay given the limited traction.

Just to be different for Nationals, I think I will order two 295's for the front and two 285's for the back...unless a kumho shipment comes through.