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Widened OE PP wheels and 315/35 MPSS

Discussion in '2013-14 Shelby GT500' started by Ky GT500, Sep 4, 2013.

  1. Ky GT500

    Ky GT500 New Member Established Member

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    Thinking of buying some rear 20" PP wheels and sending to Eric Vaughn to make them 11.5" and running 315/35/20 MPSS tires. Going 275 on the fronts. I read on here the MPSS is bigger than stated size. 295 more like 305 and so on. Just didn't want to have nasty looking bulge on rear or have rubbing issues. BMR/Eibach suspension goes on tomorrow so that won't be an issue. I've searched and have seen guys running spacers behind OE wheels, I'm not a fan of that and I prefer to stay with the OE wheel, not interested in aftermarket wheels.

    Or,,,,,should I save the money and just run the 295's on the my stock 9.5" 20's and call it a day???

    Thanks for the help/ideas.
     
  2. BANDIT HPT

    BANDIT HPT Active Member Established Member

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    I know 2 local guys who had 295's on their stock PP wheels. One had nitto invos and the other had MPSS. The Invo had a very noticeable bulge. The MPSS looked almost factory IMHO. I think the side wall if very thick on those tires and hides the bulge... but I could be wrong.
     
  3. Crowley

    Crowley Okey doke Established Member

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    I think the problem might be in the offset once the wheel is widened. I am guessing once widened, a spacer is needed to bring the wheel back out some. I'm not expert though so hopefully someone will chime in for you :)

    Crowley
     
  4. Ky GT500

    Ky GT500 New Member Established Member

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    Thanks guys!! Still researching this.
     
  5. biminiLX

    biminiLX never stock Established Member

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    You might also want to try Weldcraft in Michigan, they are well known for doing excellent widening, just they stopped doing Alcoas, so Eric Vaughn is the only option for those. EVM did the Alcoas I have and they look great, I will be having Weldcraft widen a set of stock base wheels shortly to run 315 DRs.
    Are you adding a lot of power?
    If you're staying close to stock power, I think the wide 295 (105Y) MPSS on the factory rim is the best option. Then upgrade to widening and 315s if you want later, just my opinion as you know we'll need to replace rear rubber regularly ;)
    -J
     
  6. Ky GT500

    Ky GT500 New Member Established Member

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    James,,,,I'm running Revan Racing 13-6 and 10% OD lower pulley,,,haven't dynoed yet but prob low to mid 700's RWHP,,,,Eibach/BMR goes on tomorrow. Just thinking ahead about the widened PP wheels. Like the stealth look but more tire under it. Subtle stuff done but a lot of punch.
     
  7. scottGT500

    scottGT500 Active Member Established Member

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    Sub'n
     
  8. 91z28350

    91z28350 New Member Established Member

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    I had the 315/35/20 MPSS on my 20x11 CS-1's. I know they're a different wheel, but my MPSS actually hit the wheel well lip on my FRPP lowered car w/bmr adj panhard. Ended up going with the 305/30/20 MPSS, no issues, lost about .3 in width (12.3/305 12.6 315) and that allowed them to tuck in nicely. Great tires!!
     
  9. Catmonkey

    Catmonkey I Void Warranties! Established Member

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    I've done this and documented it here. 11.5" will be too wide with the OEM offset and throw more rubber into the inner fenderwell. I have rubbing with 11" which required a 1/4" spacer to clear up. Going 10.5" should give you the right offset and will still work with the 315.
     
  10. Ky GT500

    Ky GT500 New Member Established Member

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    Nice write up Catmonkey,,,got me thinking 91z,,,,,,really not a fan of spacers. Is adding a inch worth the effort and expense?? Will 10.5" make 315's have a bulge,,,don't want my rear looking fat:D
     
  11. Catmonkey

    Catmonkey I Void Warranties! Established Member

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    The offset of the OEM wheel at 10.5" is going to be +63 mm. The CS-1 has a +55 mm offset. In effect the center of the tire will be 8 mm (.28") further from the outer fender. So the buldge mentioned wouldn't affect you. The difference between 315 and 305 is 10 mm (.39"), so the wider width brings it that much closer to the outer fender and the reason 305 is a better fit. 10.5" is the minimum wheel width spec'd for most 315s.
     
  12. biminiLX

    biminiLX never stock Established Member

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    I am going to do spacers and ARP wheel studs from Steeda if needed. If you use quality wheel spacers there are no issues professional race teams do it all the time and I've done it on several cars no issues.
    If you have 700+ I'm with you on doing 315s but I'd personally run a drag radial if you really want it to hook. I'm impressed with the NT05Rs so far.

    Cat monkey: great write up. Do we know if the '13-14 wheels have the same offset as the previous PP wheels?
    I will be running 20" base wheels on all corners with the rears widened to 11 or 11.5" still debating. I'll do what it takes to make it work. Will run 275/35 and 315/35s and FRPP springs should be sweet :rockon:
    -J
     
  13. Eviltwins344

    Eviltwins344 Creepy Lurker Established Member

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    I wish I had more time, I have a set of PP wheels widened to 11.5" and have Mickey Thompsons on them (305x20) sitting on my garage floor. When I get the time to bolt them on i will let you know.

    With the 305's on there the rim hangs out wider than the tires, kinda that nasty Euro/ricer look. I plan on burning them off (kinda spent alredy) and getting a 315 of some sort.
     
    Last edited: Sep 5, 2013
  14. 2112

    2112 New Member Established Member

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    That thread is closed, did you ever post pics with the 3/8" spacers?

    Did you use any spacers up front?
     

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