Thoughts 205 vs 225?

I am replacing the Toyo R888s on my Miata this spring, and I am looking for some advice on going to a larger sized tire. I currently run a 205/50/15 on a 15 x 7.5 rim (lTraklites). I have the option of a 225/45/15 R888 available (which appears, based on my math, to be marginally shorter overall).

My car has a reasonably fresh 1.8 conversion, with a Torsen. But no additional power -- is it possible to "over-tire" a relatively light, low-powered car with this choice?

The car is used all summer for both HPDEs, and for autox. I know I won't be competitive against other Miatas running 13 inch Hoosiers or Kumhos, but that's not my goal.

Thoughts?

Rob

The only thing I would check, is clearance. Rubbing on fenders or other parts. Check at full lock also.

Darn. I was hoping for Slant Six stuff.

slantvaliant wrote: Darn. I was hoping for Slant Six stuff.

In my dream garage I have a car that requires such an answer.

slantvaliant wrote: Darn. I was hoping for Slant Six stuff.

+1

My brother and I were just discussing Slant Sixes yesterday. We found a 67 4 door sedan on EBay, probably woulda bought it had it been a 2 door sedan as my parent's first car when they came to the US in '70 was a '67 white 2 door sedan. My brother grew up in that car, he refused to sleep unless he was in that car and it was moving.

Anyway, +1 for 225s.

I've been told by a Spec Miata racer (who also works at Tire Rack, and knows tahrs purty good) that on a Spec, the 205s are faster. This could be due to higher rolling resistance, but it could also be due to the fact that they're forced to use 15x7 wheels and that's just not wide enough.

The FM Westfield is faster on 225 tires on 15x8 wheels than it is on 205s mounted on 15x7s. Light car, not a low power car.

Tough call with the 15x7.5.

I've got a friend running 225s on 15x8 wheels with good results.

For 944Spec we're required to use 225/50/15 on 15x7 wheels. Seems to work fine. Power/Weight is pretty comparable to a Miata, so I don't think you need to worry about "too much" tire for an "underpowered" car.

I have not tried it for myself on my Miata, so I can't say for sure.

I'd say, if you're not trying to compete, the extra tire can't hurt, and you'd be able to gather valuable data for everyone.

marginally shorter yes but I looked at it at this web site

http://www.rims-n-tires.com/rt_specs.jsp

to see the measurement difference and the 225 was one tenth of an inch or 4mm shorter. not enough difference to matter in that respect.

I looked at my rims today, and discovered (or more than likely re-learned) that they are 15 x 7, not 15 x 7.5. Looks like the 205 is still a better choice. They are also cheaper, so that's a win, too.

And 3 lbs lighter, if memory serves correctly. That's what I run on the Targa car. Although when I run out of tires, I might pick up a set of new TR Motorsports C3 15x9s for use with 225s. Apparently the increase in grip over the same tire on a 15x8 is startling.