[Rpaulg87]

I need to buy new rear tires soon and I'm not sure what size to go with, I'd like beefier tires in the rear but don't want to mess up my speedo, would 275\40\20 effect it? If so what is the highest I can go and what would you recommend? I've been looking into the Nitto Invos....thanks in advance

 

[spencer60]

No problem, since you have a Predator. Just enter the new rear tire size in it (either inches-diameter or the actual metric size) and it will adjust the ECM so you're speedo is still accurate. Don't know if there's a maximum size you can enter though.

 

[skialfs]

And if you don't have a tuner, this is a great tool!!

Tire size calculator

Have fun and use it in good health. See, having a Miata is a good thing too!
Ski...

 

[Bonez]

And, if you don't have a tuner, just keep the height of the new tire within maybe a half inch of the stockers. It's hard to use tire calculaters because different brands can be different sizes, even if stated size is the same.