tire size recommendation for 15" wheels

[punkzdriver]

So, I am in the process of putting the 300zx brake kit on my car. Overkill for my 1600 but oh well. Anyway, the 15" wheels that I have on the car now with 6.5" wide tires "just" fit over the calipers. I am debating buying the ebay Rota wheels with the +12 offset that have been used by other members noted in my other post.
I can use the same tires I have now because the wheels I have now are either 6" or 6.5" wide and have 185 tires on them. I rather get 205 size tires for a 7" wide wheel. But what height tire should I get to keep a lower profile but still have the speedo remain set?

Thanks!

[jrusso07]

I am not sure how to do the calculations ....someone here knows...but you can get different speedo drive gears...easy to change out from side of transmission. Color of gear dictates ratio...someone here knows those values too

[fj20spl311]

The calculators are available online.

195/50 x 15 should fit OK...most cars

205/50 x 15 should fit the front and need a little work to fit on the rear.

[dynaguy]

I have 195/50 's on my 15" Rotas. Fit very nice without any mods. Pat