69gmachine 15 Report post Posted June 30, 2011 (edited) A friend of mine stopped by this afternoon who has an SN-95 Mustang with aftermarket deep dish Cobra R style 18x10" wheels with P285 tires on the rear. Just for grins I asked him if he would let me do a test fit on the front of my car. I've test fit a 17x9 with P275 but I wanted to find out just how big I could go. It fit amazingly well! I don't think I would try to go any wider, but it just fit under the fender lip. Also, keep in mind that my outer shock towers are not stock, they were custom made to fit a P275 tire on a 9" rim. I'm pretty sure Toyo makes either a Proxes RA1 or R888 in an 18x285 size. That would be a sweet setup for the track. I took a couple of pictures using my phone, and I can't find the cable to let me download them to my computer, but I will get my daughter to help me with it tomorrow. Those fat tires look awesome from the front! Edited June 30, 2011 by 69gmachine wrong tire models Quote Share this post Link to post Share on other sites
rwcstang 204 Report post Posted June 30, 2011 thats great! i've been debating what size tire to go with with my fr500s what are the front suspension mods that made you fit the 9"? Quote Share this post Link to post Share on other sites
miketyler 15 Report post Posted June 30, 2011 My Cuda is running 275/40-17 up front and 315/35-17 on the rear. Is lowered and has a fat mean look. I don't know that I want to go 275 on my 70 Mach but I am looking hard at running 315's in the rear. Quote Share this post Link to post Share on other sites
Powershift 19 Report post Posted June 30, 2011 I have 255/40/17 fronts (8" wide wheel), with 285/40/17 (9" wide wheel) rear. I didn't want to go much wider in the front as I was afraid with the ride height I wanted I would have serious rub issues. I can't imagine stuffing a 285 front tire on! And, my front wheels already have a 4.5" backspace. LOL Quote Share this post Link to post Share on other sites
69gmachine 15 Report post Posted July 1, 2011 (edited) thats great! i've been debating what size tire to go with with my fr500s what are the front suspension mods that made you fit the 9"? I have a coil over front suspension I designed myself, but the two main things that allow such wide wheels to fit are the Wilwood ProSpindle and a shallow outer shock tower. I have a complete write up with pictures on page 5 of my cardomain site, see sig below. Yeah, I really like the look of the FR500s too. There are more tire sizes available in an 18 than a 17, but most of the FR500 knock offs are only in an 18 anyway, so that works out well. Edited July 1, 2011 by 69gmachine grammar Quote Share this post Link to post Share on other sites
69gmachine 15 Report post Posted July 1, 2011 My Cuda is running 275/40-17 up front and 315/35-17 on the rear. Is lowered and has a fat mean look. I don't know that I want to go 275 on my 70 Mach but I am looking hard at running 315's in the rear. That sounds like an awesome combination. My worry is the 315 in the back. I know it has been made to fit, but there is no room for error, and I'm worried that if I really beat on it at the track, it's going to hit something and do serious damage to the tire. If someone made a semi-race tire like the Toyo Proxes or Nitto NT555 in a 17 P295 for the rear, I would do that combination in a heart beat. Quote Share this post Link to post Share on other sites
jeff69 10 Report post Posted July 1, 2011 Did it rub at all lock to lock? Quote Share this post Link to post Share on other sites
69gmachine 15 Report post Posted July 1, 2011 (edited) I wish I could say I checked lock to lock, and I certainly intended to, but all I did was turn it about half way each direction. With no engine running and therefore no power steering, turning just one of those big meats at all was a chore. I was trying to do this little science experiment as fast as I could as my friend was on his way home and I didn't want to hold him up. However, I could see no reason why it wouldn't make it all the way to a full turn. I've checked a P275 lock to lock and it had plenty of room. Edited July 1, 2011 by 69gmachine clarification Quote Share this post Link to post Share on other sites
SM69Mach 68 Report post Posted July 1, 2011 That would be awesome. I tried to run a 18X9 with a 275 up front with the stock style suspension and it worked ok until I lowered the car. Once I lowered the car, I had no room for that size of a tire. I dropped to a 245/45 on a 17X8 in wheel and it fits great with no issues of rubbing. Out back I am running a 18X10 with 305/35. Now I did have to message the front inner fender well, and roll the fender lips (it went to the body shop anyway for paint, so I had them do it). Quote Share this post Link to post Share on other sites
69gmachine 15 Report post Posted July 2, 2011 The only way she could get the pics off my phone was to text them, so the resolution is pretty bad, but you can see it fit under the wheel well. Quote Share this post Link to post Share on other sites
6T9rustang 11 Report post Posted July 2, 2011 So thats a 275 on a 17x9 rim? Quote Share this post Link to post Share on other sites
69gmachine 15 Report post Posted July 2, 2011 No, that's the P285 on an 18 x 10" rim. I have 275s on 17x9s on the back and it's only marginally bigger than them. I've thought about running 275s all the way around since I have the other 2 17x9 inch rims, but I'd like to put 10" rims on the back and 9s on the front. The big problem is tire selection. The 17" tire choices jump from 275s to 315s. If I switch to 18" rims, I could put 275 35s on the front and 275 40s on the rear. I'm having trouble finding a wider rear tire that's at least as tall as a front tire in this size range. Quote Share this post Link to post Share on other sites
buening 63 Report post Posted July 5, 2011 315/35s on 17x10.5 rim out back and 245/45s on 17x8 up front (spacers for all four). No rubbing at all in the front. In the back I had to massage the front inner lower part of the wheelhouse. Going around a curve at a medium speed results in the leaf springs moving laterally and causing them to rub more. I'll be modifying the sheet metal in this location to help alleviate this issue and likely look into either a rear locating device or possibly del alum bushings. Yokohama used to make a 305 series tire, but they no longer make them. I agree though, its either 275 or 315 from what I could find in the 17" size. Quote Share this post Link to post Share on other sites
