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-   -   275x35x18 on 10 inch wheel Question (https://www.corvetteforum.com/forums/autocrossing-and-roadracing/4208423-275x35x18-on-10-inch-wheel-question.html)

Dirty Howie 11-03-2018 12:19 AM

275x35x18 on 10 inch wheel Question
 
So I have a set of NT01 tires. 325x30x19 on rear and 275x35x18 on fronts.

May switch to different wheels. Same 19x12 inch rear wheels but front are 18x10 instead of 18x9.5 (stock size)

Will the 275 fronts be better, same or worse performance wise on a 10 inch vs a 9.5 inch?

Thanks

:cheers:
DH

Nowanker 11-03-2018 04:23 PM

IMO... 9.5" is borderline narrow for a 275 anyway. I'd expect crisper response with a 10" width, would choose that size in an instant.

Hardrvin 11-03-2018 06:49 PM

Better

cpt11gs 11-03-2018 09:56 PM

Better for sure.

Dirty Howie 11-03-2018 11:28 PM

Thanks guys.

Wonder why GM went 9.5 instead of 10 ??????

:cheers:
DH

fatbillybob 11-04-2018 10:03 AM

275 and 325? Doesn't that understeer badly?

Dirty Howie 11-04-2018 07:14 PM


Originally Posted by fatbillybob (Post 1598276042)
275 and 325? Doesn't that understeer badly?

All depends on how you drive Carl :D

So I have a new set of wheels (see pic in first post). Stock rear size but fronts are 10 inch instead of 9.5 on 18 inch fronts.

I have put my MPSS 285F and 345R on them and really like the way in handels. The offset gives it a wider stance which I think should improve performance.

Right now I am running 275/325 NT01 on stock sized C6Z06 wheels. Am thinking of getting another set of these new wheels so want to make sure I will not suffer a performance hit on the front 10 inch wheel.

Next set of tires I would like to get the 345 rears but not sure what will work in front without the computers having a shitfit !!

:cheers:
DH

Kubs 11-06-2018 12:30 PM

I run 275's on 18x10.5" wheels. The fit is perfect.

Dirty Howie 11-06-2018 06:20 PM


Originally Posted by Kubs (Post 1598288830)
I run 275's on 18x10.5" wheels. The fit is perfect.

Nt01 tire??

:cheers:
DH

bespokez06 11-08-2018 08:29 AM

Go big (on the front)!
 

Originally Posted by Dirty Howie (Post 1598270398)
So I have a set of NT01 tires. 325x30x19 on rear and 275x35x18 on fronts.

May switch to different wheels. Same 19x12 inch rear wheels but front are 18x10 instead of 18x9.5 (stock size)

Will the 275 fronts be better, same or worse performance wise on a 10 inch vs a 9.5 inch?

Thanks

:cheers:
DH

The closer you can get to a "square" setup the better. If you can accommodate a 305 that will result in less understeer, better turn in, braking and overall balance. We are taking this as far as we can go on my C6Z, with which I won the 2017 NASA TT-1 Championship (the car was also used for autocross). It has 18x12 fronts with 315s, and we are modifying the alignment to fit 335s. Even if you don't go that extreme, try to get to, or over, the 300mm mark. And all else being equal, a one inch wider rim makes the same width tire perform better.

Dirty Howie 11-08-2018 09:51 AM


Originally Posted by bespokez06 (Post 1598299823)
The closer you can get to a "square" setup the better. If you can accommodate a 305 that will result in less understeer, better turn in, braking and overall balance. We are taking this as far as we can go on my C6Z, with which I won the 2017 NASA TT-1 Championship (the car was also used for autocross). It has 18x12 fronts with 315s, and we are modifying the alignment to fit 335s. Even if you don't go that extreme, try to get to, or over, the 300mm mark. And all else being equal, a one inch wider rim makes the same width tire perform better.

Thanks for the input.

I have my 285/35/8 MPSS on new front 18x10 now and they look a little stretched. But maybe the looked wrong on the 9.5 and i didn't realized it.
I am willing to put a wider tire than the 275 on front and even go to the 345x12 on rear after I burn thru these brand new (1 auto day so far) as long as AH still works and I don't get the other issue (forgot the name when the size difference is too great between fronts and back). Will check Tirerack for sized but didn't see anything that seemed to be compatible with wheel sizes I have (19x12 and 18x10).

:cheers:
DH

crimlwC6 11-08-2018 10:37 AM

Square is best, as well stated above. Why do you think you need the absolute widest tire possible on the rear? 305 square or 320 square is pretty damn perfect.

Dirty Howie 11-08-2018 03:24 PM


Originally Posted by crimlwC6 (Post 1598300681)
Square is best, as well stated above. Why do you think you need the absolute widest tire possible on the rear? 305 square or 320 square is pretty damn perfect.

I tried the 18x13 with 335 and 18x11 with 315 and I could not putt down the street without AH kicking in. I don't like the way 18 inch wheels look in the back. So I know I am compromizing ..................

Boosted_Z 11-08-2018 05:35 PM

I am the oddball for sure but I run NT01 in 315/30r18 and 325/30r19. I run this as I use my stock GS wheels when temps get low and such (275/35/18 and 325/30/19). I am not competitive enough but still run NT01 315/325 for summer and Autox. I know I compromised with 18/19 but the 275/35r18 and 315/30r18 are very close to sizes and never have any issues with AH or have to worry about rake/ride height changes.

crimlwC6 11-08-2018 09:42 PM

I'm not trying to be difficult but if you are still using A/H then tires shouldn't be a huge concern. A/H can be an effective tool to learn the car but you need to turn it off to get the full benefit of tires and the corvette chassis.

Dirty Howie 11-09-2018 12:57 AM


Originally Posted by Boosted_Z (Post 1598303584)
I am the oddball for sure but I run NT01 in 315/30r18 and 325/30r19. I run this as I use my stock GS wheels when temps get low and such (275/35/18 and 325/30/19). I am not competitive enough but still run NT01 315/325 for summer and Autox. I know I compromised with 18/19 but the 275/35r18 and 315/30r18 are very close to sizes and never have any issues with AH or have to worry about rake/ride height changes.

You run a 315/30/18 on the stock 9.5 inch wheel?

Dirty Howie 11-09-2018 12:59 AM


Originally Posted by crimlwC6 (Post 1598304987)
I'm not trying to be difficult but if you are still using A/H then tires shouldn't be a huge concern. A/H can be an effective tool to learn the car but you need to turn it off to get the full benefit of tires and the corvette chassis.

Your not being difficult. I am talking about driving on the street to the AutoX event wanting to have AH on. Not when actually doing the event. :rock:

:cheers:
DH

Boosted_Z 11-09-2018 03:38 AM

No way would I use 315 on 9.5 wheel. I only use my 9.5 wheel when I run my 275 sized for off season use. Sorry if my message was not clear.

I have a few sets of wheels and all have TPMS and just do a quick re learn when I swap . Although I do not use AH while while some events, I still have sensors and such as The only alternative I would do is a LG track box. Too many threads about AH kicking on/off during events and with everything disabled too. Do not know the solid truth on this but with sensors and that staggered sizes I run- there will be no issues so not my concern.

crimlwC6 11-09-2018 08:58 AM


Originally Posted by Dirty Howie (Post 1598305569)
Your not being difficult. I am talking about driving on the street to the AutoX event wanting to have AH on. Not when actually doing the event. :rock:

:cheers:
DH

:cheers:

bespokez06 11-09-2018 09:05 AM

I may be misunderstanding here, but is the AH you are referring to the stability control system, and it kicking in due to the TPMS system sending incorrect info? If so, yes, get a box to be able to turn it off 'for good', while still turning it on for street, rain, etc. I had that problem at a TT in Utah. I would literally go drive 20+ miles on the street to reset and then pull onto the grid to do my laps before I got one and fixed the issue! There is another company in Michigan that makes a box that turns it off. Anthony Forney at HP Research can direct you to them. Back to main point: Run the widest you can on front once current ones are used up. That could take a while! My MPSSs still look almost new after using them for multiple track days and auto-xs in 2016. Hsun Chen, a great driver, ran the Falkens for his first ever OneLap this year and was 7th overall and won as top Rookie for that event, so those tires are another alternative. Once either BFG Rival S or Bridgestone RE-71R come out in the staggered rim dia. you want, they'd be a great all-round option. They're about 2sec slower than a Hoosier A7 but last a whole season for most folks, and are streetable, and 2sec faster than the MPSS.


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