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Widening Alcoa Wheels

Discussion in 'SVT Shelby GT500' started by JLD, Aug 25, 2013.

  1. JLD

    JLD New Member Established Member

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    Is it better to widen my 20x9 or 20x10 wheels and how wide can I go without modifying my bump stops?
     
  2. Robert M

    Robert M 800 HORSE FUN!! Established Member

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    If you want to move the 10's to the front, then the 9's would need to be widened. I believe 11.5" is what most guys have found to work for full travel of the axle.

    I did 12" and have not modded anything on my car except to remove the Eibach rear shock boots and the rear brake ducts that were installed on my car at Shelby Las Vegas. When I raise my car on a 2-post lift, it is a two step process, but to me it is worth it, I wanted the wider size Alcoa's on the rear and also no cutting on my car.

    I have had no issues with bump stop contact for over two years now.......

    011-4.jpg

    ^^^10's on the front and 9's widened to 12".



    R
     
    Last edited: Aug 26, 2013
  3. MichaelFreedman

    MichaelFreedman New Member Established Member

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    What brand tire do you have on that car, what size? Any rubbing at all under real hard cornering? I've got the griggs stuff in my car and it's pretty low, but with the Watts link. I've really wanted to widen the wheels as you have but am afraid to pull the trigger without more positive feedback. I will be driving this thing pretty aggressively and don't want to have any issues.

    Mike

     
  4. Robert M

    Robert M 800 HORSE FUN!! Established Member

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    I have Dunlop SP Sport Maxx GT's all the way around, 275/35 front and 325/30 rear. I have taken the car into some relatively hard corners with no contact issues, but I would not want to say that this would work perfect for all GT500's/Mustangs. There seems to be some differences in the inner fender areas when comparing from car to car, some guys have had contact issues with 11.75's and 315's and other have had to use spacers with 11.75 and 325's. All I can say is that it fits for me. I am more of a straight line guy so I have not experienced extensive hard cornering in my car.

    The bump stops will only be an issue with tire/wheel drop, it will be inner wheel well tire contact that would be an issue with hard cornering I assume? If the axle assy, does not move side to side, you should be alright with the wider widths?



    R
     
  5. JLD

    JLD New Member Established Member

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    I have 2 full sets of alcoas so I'm not consernd about putting 10's up front I wasn't sure if the 9's had a different offset from the 10's I think I'm going to end up widening them to 11-1/2 to be safe n
     
  6. Steve@TF

    [email protected] Authorized Vendor Authorized Vendor

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    theyre the same.
     
  7. psucobra

    psucobra Member Established Member

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    Would it be safe to say that I could run 11.5 Alcoas on the rear and maintain full suspension travel without having to modify the bump stop or remove the dust boots? What tires size and brand are you guys with 11.5s running without interference issues?
     
  8. Robert M

    Robert M 800 HORSE FUN!! Established Member

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    ^^^^Yes, this is what I have heard. 11.5 should be fine, but that also limits the tire width to 305-315 unless you don't mind a big bulge out past the fender lip.



    R
     
  9. biminiLX

    biminiLX never stock Established Member

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  10. Robert M

    Robert M 800 HORSE FUN!! Established Member

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    Nitto's (at least Invo's) do run on the narrower side so that would need to be taken into account if another tire brand is chosen in the same size, the other tire could stick out further than some would like with an Alcoa.

    11.5" is about as wide as the rim can go without bump stop contact. It is the inner portion of the rim that rests on the bump stop and does not allow full travel of the axle when the suspension-tire(s)/wheel(s) is/are dropped out of the wheel well as shown below.

    Shown in the picture below is how much the tire/wheel would need to drop to contact the bump stop. I have never come across a situation where my rear tire/wheel assy. has dropped out on either one side (like entering my right turn incline driveway) or both sides (except on a two post lift) where I need to worry about bump stop removal with my 12's.

    003-2.jpg


    ^^^Here is the body on jack stands and the Alcoa resting on the bump stop bracket. This is wayyy more drop that anything I would experience in normal driving, so I felt there was no need to cut on my car for bump stop removal. This is the 325/30 Dunlop.

    This is the 335/30 Michelin Pilot Sport PS2 for a comparision...........

    004-1.jpg


    ^^Sorry for the blurred picture. The 335/30's had a little more bulge past the fender than I was interested in, so the 325/30's were installed instead for a "closer to flush fender look".


    R
     
    Last edited: Aug 27, 2013
  11. biminiLX

    biminiLX never stock Established Member

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    True, I ordered zombeast's bumpstop relocation in anticipation of that and maybe using 18x12s and 345s for the strip down the road. At this point I'm thankful they're not needed, but it will be lowered soon and I might just do it while we're in there doing the suspension mods.
    Your posts have been very helpful while I've been researching, car looks great with those wide meats!
    -J
     
  12. Robert M

    Robert M 800 HORSE FUN!! Established Member

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    ^^Thanks.

    The relocation brackets are needed if a person does not want to hassle with using a floor jack and removing the rear tires before their car is lifted on a 2-post lift and also to insure full travel of the axle at all times, in any situation. Me personally, I have not encountered a situation in my driving where I have had contact, so I thought I would give it a try without cutting my brackets.......but I also have a pair of those nicely designed relocation brackets, the price is right and the Zombeast bracket design and construction is Very Nice.



    R
     
  13. TORQJNKY

    TORQJNKY Authorized Vendor Authorized Vendor

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    I put my 201x10's up front and widened the 20x9's to 11.5". NO, you WILL NOT get full travel with an 11.5" Alcoa without modifying the bump stop bracket. The inner wheel will contact the bumpstop bracket when you jack up the car unless you do like Robert M suggests by using two jacks or jack it up by the pumpkin. Additionally, you will only get about 1/4" tire bulge with a 315 series R888. Read through my thread below for more info. Hope this helps.

    http://www.svtperformance.com/forums/2013-shelby-gt500-413/906245-eric-vaughn-widened-alcoas.html
     
    Last edited: Aug 28, 2013
  14. Robert M

    Robert M 800 HORSE FUN!! Established Member

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    This is good to know also, someone from first hand experience has found that not even 11.5" Alcoas will clear the bump stops.................so that really limits the tire size to what will properly fit on 11" or maybe 11.25" if you want to retain full axle travel at all times and don't want to cut on your car.


    R
     
  15. evasive

    evasive Well-Known Member Premium Member Established Member

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    I went with 10" up front and 11.75 out back with the bump stop relocation brackets, QA1 rear shocks, and 315 R888 tires on the rear. No issues.

    Www.2008GT500.blogspot.com
     
  16. biminiLX

    biminiLX never stock Established Member

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    Car looks great, love the color.
    -J
     
  17. JLD

    JLD New Member Established Member

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    I would like to run 315/35/r20 Nitto NT05R Drag Radial on a 11.5 rim
     
  18. biminiLX

    biminiLX never stock Established Member

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    Other than adjustable FRPP panhard bar, I run that tire on an 11" Alcoa and made no other mods.
    11.5" isn't necessary and there isn't much bulge on the 11". I do think if I ordered the Alcoas myself, I probably would have gone 11.5" as its same price.
    -J
     
  19. JLD

    JLD New Member Established Member

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    Has anyone tried the Mickey Thompson ET Street2 drag radial (305/35/20) I'm wondering if this tire is better or worse than the Nitto
     
  20. psucobra

    psucobra Member Established Member

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    I would like to know what tire fits best on the 11.5 widened Alcoa with minimal to no bulge or stretch, can't stand either.
     

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