Getting Tires ... Need Wheels
OK, some mis-information in this thread:
T2 350Zs in 2006 (I think) were given an allowance to run 18 x 9.5" front and 18 x 10" rear wheels and that's the size most all of the cars were running at the Runoffs.
Regarding manufacturer recommended rim widths for tires:
DOT actually specifies the formula the manufacturers use to determine recommended rim widths and its based on safety factors. If you call the racing side of the tire manufacturers (Jeff Speer at Hoosier, Rudy at Kumho) they give a slightly broader range of rim width for possible and safe fitment but a much narrower range (1/2") for ideal fitment and performance.
Regarding safety:
Its your ***, make your own decisions.
T2 350Zs in 2006 (I think) were given an allowance to run 18 x 9.5" front and 18 x 10" rear wheels and that's the size most all of the cars were running at the Runoffs.
Regarding manufacturer recommended rim widths for tires:
DOT actually specifies the formula the manufacturers use to determine recommended rim widths and its based on safety factors. If you call the racing side of the tire manufacturers (Jeff Speer at Hoosier, Rudy at Kumho) they give a slightly broader range of rim width for possible and safe fitment but a much narrower range (1/2") for ideal fitment and performance.
Regarding safety:
Its your ***, make your own decisions.
ib4tl
As I said before SOLO-350Z, come to Topeka with your 235s.
I believe that it was 2007 that the T2 350Zs were permitted the wider wheels, because I see pictures of 350Zs at the 2006 Runoffs on older Enkei RPF-1s (max width of 9.5 inches), but I could be mistaken (I know that one competitor told me that he was getting 285s mounted on track wheels at the Runoffs).
Racing is about (safely) pushing the envelope. For freshly-mounted 285s, I don't think that I would feel comfortable pushing them. After letting them "relax" and fully seat on the bead, I don't see any problems (safety or otherwise) running them. In actuality, the 285/30s have *more* sidewall than 245/35s -- by 1/4 inch!
As I said before SOLO-350Z, come to Topeka with your 235s.
I believe that it was 2007 that the T2 350Zs were permitted the wider wheels, because I see pictures of 350Zs at the 2006 Runoffs on older Enkei RPF-1s (max width of 9.5 inches), but I could be mistaken (I know that one competitor told me that he was getting 285s mounted on track wheels at the Runoffs).
Racing is about (safely) pushing the envelope. For freshly-mounted 285s, I don't think that I would feel comfortable pushing them. After letting them "relax" and fully seat on the bead, I don't see any problems (safety or otherwise) running them. In actuality, the 285/30s have *more* sidewall than 245/35s -- by 1/4 inch!
Originally Posted by PDX_Racer
ib4tl
As I said before SOLO-350Z, come to Topeka with your 235s.
I believe that it was 2007 that the T2 350Zs were permitted the wider wheels, because I see pictures of 350Zs at the 2006 Runoffs on older Enkei RPF-1s (max width of 9.5 inches), but I could be mistaken (I know that one competitor told me that he was getting 285s mounted on track wheels at the Runoffs).
Racing is about (safely) pushing the envelope. For freshly-mounted 285s, I don't think that I would feel comfortable pushing them. After letting them "relax" and fully seat on the bead, I don't see any problems (safety or otherwise) running them. In actuality, the 285/30s have *more* sidewall than 245/35s -- by 1/4 inch!
As I said before SOLO-350Z, come to Topeka with your 235s.
I believe that it was 2007 that the T2 350Zs were permitted the wider wheels, because I see pictures of 350Zs at the 2006 Runoffs on older Enkei RPF-1s (max width of 9.5 inches), but I could be mistaken (I know that one competitor told me that he was getting 285s mounted on track wheels at the Runoffs).
Racing is about (safely) pushing the envelope. For freshly-mounted 285s, I don't think that I would feel comfortable pushing them. After letting them "relax" and fully seat on the bead, I don't see any problems (safety or otherwise) running them. In actuality, the 285/30s have *more* sidewall than 245/35s -- by 1/4 inch!
285/30 = 85.5mm of sidewall in all directions (i.e. 171mm of sidewall height total, or ~6 3/4")
245/35 = 85.75mm of sidewall in all directions (i.e. 171.5mm of sidewall height total, or ~6 3/4")
FYI: You guys have made an interesting argument which has made an impact on me. I put my 255/40 tires, which are on a 17x8 wheel, for sale, and already ordered additional 275/40 tires for autox.
Interestingly enough, I plan to run in the Street class of the Redline Time Attack Series held at Laguna Seca this November. I have a dedicated track set of CCW wheels, 17x9.5, that I run 275 Hoosiers on, however, one of the limitations of the street class is a 140 tread rating or better. I'll be able to put the 275s all-around on the CCWs with RT615s, but my back-up wheels are the same autox wheels that I referred to above, and have a hint of fear of tracking the 275 front tire on the 17x8" wheel. Seca is all walls, and would be a damned place to pay for a lesson... I certainly don't want to be the first data point...
Info for the RLTA: www.redlinetimeattack.com
Do you guys have further thoughts?
BTW, I plan to drive my Z32TT in the RLTA, not the Z33 (which I autox).
Interestingly enough, I plan to run in the Street class of the Redline Time Attack Series held at Laguna Seca this November. I have a dedicated track set of CCW wheels, 17x9.5, that I run 275 Hoosiers on, however, one of the limitations of the street class is a 140 tread rating or better. I'll be able to put the 275s all-around on the CCWs with RT615s, but my back-up wheels are the same autox wheels that I referred to above, and have a hint of fear of tracking the 275 front tire on the 17x8" wheel. Seca is all walls, and would be a damned place to pay for a lesson... I certainly don't want to be the first data point...
Info for the RLTA: www.redlinetimeattack.com
Do you guys have further thoughts?
BTW, I plan to drive my Z32TT in the RLTA, not the Z33 (which I autox).
Last edited by scotts300; Aug 9, 2007 at 08:27 AM.
Hallelujah! The light bulb finally turned on! 
Here's a pic of my Z from this past weekend's auto-x with 275/40/17 r-compound tires mounted on four 17x8 OEM powdercoated rims. With this setup, I can rotate the tires anyway I want, and you definitely have more grip with the wider tires on all four corners. My tires are still new (14 runs) so they still need to be scrubbed some more to be stickier.
Here's a pic of my Z from this past weekend's auto-x with 275/40/17 r-compound tires mounted on four 17x8 OEM powdercoated rims. With this setup, I can rotate the tires anyway I want, and you definitely have more grip with the wider tires on all four corners. My tires are still new (14 runs) so they still need to be scrubbed some more to be stickier.
Last edited by z-u-later; Aug 9, 2007 at 08:17 AM.
Originally Posted by z-u-later
Hallelujah! The light bulb finally turned on!
Here's a pic of my Z from this past weekend's auto-x with 275/70/17 r-compound tires mounted on four 17x8 OEM powdercoated rims. With this setup, I can rotate the tires anyway I want, and you definitely have more grip with the wider tires on all four corners.
Here's a pic of my Z from this past weekend's auto-x with 275/70/17 r-compound tires mounted on four 17x8 OEM powdercoated rims. With this setup, I can rotate the tires anyway I want, and you definitely have more grip with the wider tires on all four corners.
Thanks for the pic; do you have a close-up of the wheel/tire itself?
Originally Posted by z-u-later
Oh, yeah, typo! Changed from 275/70 to 275/40. I'll see if I can find a closeup pic.
I'll see if I can find a closeup pic.
Originally Posted by balaguru
Just to clarify: that was Thompson. I'm nowhere near that fast but when someone does well at that level with a particular setup I pay attention, as I imagine any decent racer does.
I pay attention. Let the pics speak:
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