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Discussion Starter #1
Just wondering if this tire will work for someone that plans to opentrack twice a year. The setup planned is:

front 265x35x18 9" rim
rear 295x35x18 10" rim


Thanks
 

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Other than that, the MX is a terrific track tire for someone who doesn't want to swap tires from street to track. That's why I'm on my 4th set ;)
 

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This will be my 3rd season with the MX tire. It is a really good tire for track & street. I have nearly 22k miles, 5 OT events, & 4 trips to the Drag strip on mine and they still have a decent amount of tread left. As they wear, they seem to get better and better on the track. On real hot days (like the July trip to Gingerman with SAAC) they tend to get a bit greasy by the end of the 20 minute sessions. Other than that, I like them. This year however, I am going to be switching to race rubber for my track days :)
 

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Discussion Starter #5 (Edited)
Glenn said:
A 295 is too wide for a 10" wheel and the front to rear diameter difference will disable your ABS.

Next question?
hmmm. I currently run a 285 nitto (narrower i know) on a 9" with NO rim hangover, so I figured a 10" would make easy work of a 295. And according to tirerack, the 295 works on a 10-11.5" rim.

Next question? ok... why does Kumho state that the 275 tire weighs in at 19.9lbs while the 265 is portly at 27lbs...?
 

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Discussion Starter #6
And per Glenn's statement on ABS, why does this 'disable' happen? Can I proram this issue away?
I'm running 450bhp. Since I am no longer running drag radials (in an effort to be more $ effective and OT ready), I surmise i need a little larger contact patch to offset the fact that I won't have as sticky a tire on back (as I still like to have fun on gratiot on occassion) and would like to avoid breaking loose in 3 gears....
 

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blacksnake305 said:
Just wondering if this tire will work for someone that plans to opentrack twice a year. The setup planned is:

front 265x35x18 9" rim
rear 295x35x18 10" rim


Thanks
By the way, watch out for hydroplaning in the rain with wider rears vs fronts. The rear end becomes very happy. I experienced this and it's not fun. Something to keep in mind.
 

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blacksnake305 said:
And per Glenn's statement on ABS, why does this 'disable' happen? Can I proram this issue away?
Because the ABS works on the principle of wheel speed. Once brakes are applied it uses the wheel speed data to determine which, if any tires are starting to lockup. The ABS system will momentarily release hydraulic pressure to the caliper of the wheel moving too slowly until wheel speed data matches that from the other sensors. To do that it must have accurate wheelspeed input data. With a difference in tire diameters the wheel speeds will not match front to back. If the wheel speeds are different with no brake applied the ABS computer assumes a system malfunction, turns on the ABS warning lamp and shuts the system down to prevent an accident due to faulty data iinput.

As for the 295 tire fitting a 10" wheel, go for it if you must. But, FWIW I run 10.5" wheels and a 295 is too wide for my wheel. I'm going back to a 275 on my next set. Just because you can squeeze that large a cross section tire onto a 10" wheel doesn't make it a good fit. Use a wheel size that is at least in the middle of the range for the tire being considered and you will put down a bigger footprint and have better turn-in. A narrow wheel lets the tire sidewall flex excessively resulting in a slow turn-in and less precise handling. For drag cars this isn't as big an issue and guys commonly run slicks wider than the wheel width. With a track car you want the wheel width and tire width to be matched as well as possible to improve stability.
blacksnake305 said:
why does Kumho state that the 275 tire weighs in at 19.9lbs while the 265 is portly at 27lbs...?
They don't. The Kumho website http://www.kumhotireusa.com/Products/PtnDetails.asp?mainCatID=1&PtnID=KU15 states the 265 is 26.1# and the 295 is 30.5#, man those are some heavy tires. My V710 in 295-40-17 is about 5# less per tire. I guess the 18" sizes weigh more? I know the 18" wheels are heavier, but the tires too?
 

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Discussion Starter #12 (Edited)
serpentnoir said:
Maybe I should have ordered two sets. :)
glenn. thanks for the education.

Eric: I run 18's

And thanks all. FWIW, i dont think I want to make my Vert a pure OT car. I think I will need to get a heavily used 99' cobra and get real serious (when that time comes). For now, this pig vert will see street duty w/ occassional OT time (but only for the fun of it). Now I dont feel so bad about my heavy ass wheel/tire combo. LOL...
 

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Discussion Starter #13
They don't. The Kumho website http://www.kumhotireusa.com/Products/PtnDetails.asp?mainCatID=1&PtnID=KU15 states the 265 is 26.1# and the 295 is 30.5#, man those are some heavy tires. My V710 in 295-40-17 is about 5# less per tire. I guess the 18" sizes weigh more? I know the 18" wheels are heavier, but the tires too?[/QUOTE]

acutally they do, remember i'm talking 18". the 275x35x18 weighs less than the 265x35x18. I'm just wondering why...
 

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I run a 315 on 10.5" 03 Cobra rims and the outermost part of the sidewall is pretty much in line with the lip of the rim, i.e. I could run a straightedge across the tire and it would contact the rim. I don't think that's too wide, is it?
 

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Glenn, I am not saying your right or wrong on the ABS issue but... My buddy has a 1999 Cobra with 245-45-17 front 275-40-17 rear with no ABS issues whatsoever. I just called him to ask that even though there is no ABS light on if it is still functional. He says ABS works great and that he has had no problems with it. Take it for what its worth, just thought I would say something.
 

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LT1HAHA said:
Glenn, I am not saying your right or wrong on the ABS issue but... My buddy has a 1999 Cobra with 245-45-17 front 275-40-17 rear with no ABS issues whatsoever. I just called him to ask that even though there is no ABS light on if it is still functional. He says ABS works great and that he has had no problems with it. Take it for what its worth, just thought I would say something.
Well, I'll take no issue with your statement because I'm sure that it's true. A 245-45-17 Kumho MX is 25.7" diameter and so is a 275-40-17 so there should be no problems. I think in a Nitto 555 works out the same as do most other tires ofthe same brand. But a Kumho MX 265-35-18 is 25.3" diameter, while a 295-35-18 is 26.1" diameter, a difference of over 3/4". Now that, my friend, could very well cause major problems. :)
 

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huesmann said:
I run a 315 on 10.5" 03 Cobra rims and the outermost part of the sidewall is pretty much in line with the lip of the rim, i.e. I could run a straightedge across the tire and it would contact the rim. I don't think that's too wide, is it?
Maybe, maybe not, every manufacturer seems to come up with different dimensions on tires of the same numerical size. What I see when I read that a tire is 315mm size, is a 12.5" section width, which IMHO is too wide for a 10.5" wheel. I would think a 11.5" wheel would be a better match. Then again, everyone has different ideas about what is and is not a good fit, so YMMV.
 

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Glenn said:
Maybe, maybe not, every manufacturer seems to come up with different dimensions on tires of the same numerical size. What I see when I read that a tire is 315mm size, is a 12.5" section width, which IMHO is too wide for a 10.5" wheel. I would think a 11.5" wheel would be a better match. Then again, everyone has different ideas about what is and is not a good fit, so YMMV.

Well, there's "ideal" and then there's "workable". Generally, wider rims are more "ideal". See Carroll Smith or Wm. Mathis books.

Kumho 710's seem to run wide. 275's look better (i.e., straighter sidewall) on my 10 1/2" rims than on 9" ones.

Even so, I'm going to try 315's this time around. If I like them, I may finally spring for some even wider CCW's. Those 315's are some expensive tires, so I will be sure and check my alternator output first.:)

Also, I think you can get away with more in auto-cross than for track use. Or at least due to class rim width restrictions, you see a lot of very wide tires on not so wide rims on very quick machines. E.g., 275's on 8" rims on F Stock Mustangs and also on D(?) Stock Rx8's. So, "workable" seems to trump "ideal", especially if there's no choice/budget, etc.
 

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Discussion Starter #20
Glenn said:
Well, I'll take no issue with your statement because I'm sure that it's true. A 245-45-17 Kumho MX is 25.7" diameter and so is a 275-40-17 so there should be no problems. I think in a Nitto 555 works out the same as do most other tires ofthe same brand. But a Kumho MX 265-35-18 is 25.3" diameter, while a 295-35-18 is 26.1" diameter, a difference of over 3/4". Now that, my friend, could very well cause major problems. :)
On that note, a buddy (who ran at gingerman last year) has a bullitt w/ 245 up front and 315 in the rear. No issues w/ ABS...
 
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