Crazy question,, Why do I see everyone replacing their tires with 275/40 series tires, rather than 275/35s? I have the factory 255/40-19s now and I'm questioning if I ordered the wrong size tire.

My thinking was going to a 275/40 will give me a larger sidewall and slightly taller tire. Who wants taller?

 

I wanted wider without going smaller than OEM and the 275/35 19 is smaller. Plus the 275/40 is the same basic height as the stock 245/45 that comes on the California Special so it is in the correct range for the speedo without having to tune.

 

Yep, 275/40 is just a little taller sidewall. Some folks like a little more rubber for appearance and for a slightly softer ride. I have 275/35-19's and they are pretty stiff, some might say "harsh" depending on personal preferences. The taller tire can offer some advantages in some situations; like if you want to effectively adjust your gearing a little taller, and more sidewall flex can actually give more grip in some situations.

Like Siber said, if you don't want to recallibrate your speedometer, you should match the overall diameter to the original tires. On Tire Rack you can look up the exact diameters for your old tires and any new tires you are considering to find out how close or how far off they are. While you are there, check the recommended wheel width and pick tires that match your wheels.

 

Ditto with Bert and Siber,

I used 275/40-19 for track days, it helped me make the gearing a little taller. 3.73s are a bit too short at the tracks I go to (i.e. running out RPMs with 100-200 yards to the brake zone).

I might go with 285/35 next time though for a bit more grip.

 

I went through this last spring and decided on the 275/40 19 for the reasons already stated. The only thing that I would add is that for most of the tires that I considered, the 275's were the widest tires recommended for the stock Brembo wheels. Anything wider should be done with a wheel change.

 

I have the 275/35 on mine but in a 20. These are on 9.5" rims. That is the optional size that Roush puts on the cars if you opt for the 20" rim height verses the 18". Here is a little calculator that might give you an idea of the difference between the 275/35 and 275/40 in a 19...

https://www.tacomaworld.com/tirecalc