kaizman Posted January 10, 2014 Report Share Posted January 10, 2014 I know I am probably going to get yelled at but I have a headache going through all the searches on these wheels and tire sizes. I purchased a set of 20 X 9 Alcoa's (beautiful wheels) for my 2013 GT500. Question ~ I am going to have the rears sent out to be widened and what would be the preferred width to handle 285/35Z-20 Michelin PSS without any clearance problems. I really couldn't find this discussed too much but seeing I am going to widen the rears what do you think the optimum width should be for this size. The car is not lowered it does have the performance and track packages. I assume that I may need to install an adjustable pan hard bar. It looks like quite a few people have installed 265/35Z-20's on the front 9" rims without any issues (I know Shelby recommends 255"s). Thanks for any advice Link to comment Share on other sites More sharing options...
2007tungstenGT500 Posted January 10, 2014 Report Share Posted January 10, 2014 it's been stated many times on here that a 9" rim should use nothing wider than 275. shelby specifies 255 (front) and 275 (rear) on 9" wheels so 265 would fit. however, whether it will rub or not depends on the tire manufacturer and the offset of the rim. If the Alcoa's offset is 24mm (like the Razors) then you should probably stick with what shelby specifies. if you want to widen the alcoas, i would only do the rears. you can safely go with a 10" or 11" width and run 295 or 305 without any rubbing. some have stated they have successfully run 10" upfront with 275s but i wouldn't do it myself. personally, i'm running 20x9" w/24mm offset and 265 front along with 20x11" w/24mm offset using 315 rear on a lowered car and it DOES rub on the outer edge of the fenders. next time i buy tires i'm going with 255 upfront and 305 out back. unfortunately, i know that weldcraft, a popular vendor for widening wheels no longer widens alcoas. presumably this is due to the limited availability and high cost of the wheels in the event of a mistake but i don't know that for sure. Link to comment Share on other sites More sharing options...
TMatt142 Posted January 16, 2014 Report Share Posted January 16, 2014 Eric Vaughn also widens Alcoas and does a spectacular job. I know of many Shelby owners who have widened their rims through his shop. Now whether or not it's worth it is all personal preference of course. I was quoted $350.00 per rim. So if that's something that is do-able for you, contact him and he can get you taken care of. Just make sure you know how wide you want to go. No sense in sending them off to widen out to 20 x 10 only to decide later on that you want to go wider. I would say 20 x 11 would be a safe width. I know from another member on one of the other forums who seems to have a successful combo if you want to go as wide as 315 without rubbing. It really all depends on which tire you go with as some run taller/wider than others. Link to comment Share on other sites More sharing options...
David Hawkins Posted January 17, 2014 Report Share Posted January 17, 2014 Just curious, I am sure that when you are talking about Widening the Wheels, they widen towards the back (inward). How hard would it be to widen them outward to make them Deep Dish? Link to comment Share on other sites More sharing options...
Jer Posted January 17, 2014 Report Share Posted January 17, 2014 Just curious, I am sure that when you are talking about Widening the Wheels, they widen towards the back (inward). How hard would it be to widen them outward to make them Deep Dish? Fender clearance might be an issue. I don't have an example here at home, but I can measure for you tomorrow. Drop me an email. Jer Link to comment Share on other sites More sharing options...
kaizman Posted January 17, 2014 Author Report Share Posted January 17, 2014 Thanks for the responses. Michelin states a rim width of 9.5-11" for a 285/35Z-20 PSS rear tire and before I send them out to Eric, I was wondering if anyone has run this width with a 10.5 or a 11" Alcoa rim. I just want to get it right before going through the added costs. In the future, I doubt I will go any wider than the 285's. thanks again. Link to comment Share on other sites More sharing options...
08KR525 Posted January 17, 2014 Report Share Posted January 17, 2014 There are a few threads on this very topic in the wheel & tire section in the GT500 Modification subsection. I think if you do some more research you will decide to go with a wider tire.GL Link to comment Share on other sites More sharing options...
TMatt142 Posted January 20, 2014 Report Share Posted January 20, 2014 I know of a couple guys that run even wider Alcoas. One that has widened to 12" and the other 11.75. Couple that with a bit of research on tire width/height you may get to a 325 width. It all depends on which tire manufacturer you go with as each one varies in regards to their actual ride height/width. The guy with 11.75 runs Toyo 888 @ 315/30/20 with no rubbing, and no relocation of the bump stop brackets. I wonder though, why go through the widening if you will only be running a 285? Link to comment Share on other sites More sharing options...
kaizman Posted January 20, 2014 Author Report Share Posted January 20, 2014 I think a 285 is a little too much for a 20 X 9 rim. The set of Alcoa's I purchased were these last ones just offered in only 20 X 9's with just the "Shelby forged" on the rims. Link to comment Share on other sites More sharing options...
TMatt142 Posted January 21, 2014 Report Share Posted January 21, 2014 Oh, my fault… I was thinking rears (20 x 10's) and 285. Duh, that one slipped past me! Link to comment Share on other sites More sharing options...
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