What's the widest you can go on stock rims before having to put 50's on

[CombatComProg]

What's the widest you can go on stock rims before having to put 50's on the back? I've read here that 275/60's are too tall. What about 255/60's? I currently have 235/60's on all four stock rims and would like to go as wide as possible on 60's since tirerack offers a lot more brands at that height.

 

[UNGN]

275/60's aren't too tall. They will throw your speedo off 7%, but for a high torque, low revving V6, they are great.

 

[Turbo Loyd]

What's the widest you can go on stock rims before having to put 50's on the back?

There are two issues here width and height.

As a rule to thumb you do now want to go much over two inches wider than the rim you are using. Therefore a 7 inch rim should only have a 9 inch wide tire. At 25.4 mm per inch that would be tire size 228.6. Therefore maybe a maximum of 245 or really streatching the rule of thumb 255. When you go that wide you will want to do some burnouts to see what air pressure gives you a full width patch, then stick with that pressure. Since the side wall bulges so much you may have to use a slightly lower pressure to get a full tire contact with the pavement. If course we are not advising anybody to do this.

A 275 50 15 tire is slightly under 26 inches in diameter which is the stock 215 65 15 tire height. I know my GN like the stock diameter tire. If you go 275 60 15 you might be better off with 3.73 gears. A lot of racers prefer the taller tire, since it has more footprint area getting off the line.

I use an 8 inch rim for my 275 50 15 tires, so the tires are about 2.8 inches wider than the rim. There is quite a bit is sidewall bulge.