Yet another tire size question

[MikeW]

14 years ago when I put 195/70-14's on my 14x7 slotted mags the rear tires rubbed the fenders whenever hitting a big bump or dip in the road. At the time I attributed this to sagging springs. I now have Tokico lowering springs and they still seem to rub (the car appears to ride at about the same height as before) although I haven't driven the car much seeing as how I need new tires. What size should I consider? Should I revert to 185/70 or even 185/60?

[2ManyZs]

With lowering springs and a tall sidewall such as a 70 series it's quite possible to have a rub.

Might be better off to go to a 60 or even a 55 or 50 series tire.

I've run 225/60's on 7 inch zero offset wheels with no rub with stock and also lowering springs on the street and adjustable coil-overs on the track(much lower than street specs).

[MikeW]

Thanks. I went with some H-Rated 195/60-14 Sumitomo tires. So far there isn't any rubbing, even on a big speed bump. As far as the speedometer error introduced by a slightly smaller diameter goes it looks like a visit to the local radar speed limit sign in front of the elementary school is in order.:devious:

[That Ozzy Guy]

Rather than starting another thread I thought I'd hijack this one. Hope you don't mind.

I need to know what the original tyre width the 1973 240Z's came out with on the back for engineering purposes. I think I might be in trouble on this one. :disappoin

[g260]

George,

I think you will find the original tyres front and rear were 195 70x14's

Geoff

[That Ozzy Guy]

Aargh. I'm screwed. Why couldn't it be 205? Did they ever come out with wider tyres as an extra? It's a sportscar for God's sake. How can it be sporty with 195's? :disappoin

Thanks Geoff

[thefastestz]

My 240z called for 175s

But i had 215/60s on my Z.

Its a sports car, so i couldn't hav no skinny tires.

[Alfadog]

I thought they came with 185s?

OK I'LL SHUT UP NOW

What's the deal with that, George???

[That Ozzy Guy]

The short of it is, to be legal the tyre width has to be a maximum of two inches wider than what the car came out with originally. Sooo... I'm looking for something that says the '73 240z came out with 205's as an option. I don't like my chances.

[MikeW]

Originally posted by That Ozzy Guy

The short of it is, to be legal the tyre width has to be a maximum of two inches wider than what the car came out with originally.

185 millimeters is 7.17 inches. Two inches more than that, 9.17, is 232.92 millimeters.

[tttz]

As far as the speedometer error introduced by a slightly smaller diameter goes it looks like a visit to the local radar speed limit sign in front of the elementary school is in order.

check out this link:

http://www.miata.net/garage/tirecalc.html

-Ty

[MikeW]

Originally posted by tttz

check out this link:

http://www.miata.net/garage/tirecalc.html

-Ty

Thanks for the link. If the orginal tires were 175/70-14 then my new 195/60-14's are off by 1.8% too fast. An indicated 60mph is really 58.9mph. Heck, I don't think I can hold the speedometer steady enough (without cruise control) for that to even matter.