I hope this doesn't cover ground already covered elsewhere. I did search through the forums but didn't see this exact question, so here goes.

I'm looking at a new set of tires for one of my '78 coupes.

Both have the stock 14" steel wheels. I've been pretty happy with the set of Yokohama Avid tires I have on the other '78, which I believe are 185/70R-14.

I know very little about tire design, etc. and am wondering what the difference would be if I used 195/70R-14's on this one. Is one "better" than the other for a stock 280Z as far as performance, handling, etc?

These would be used for normal everyday driving as well as the occasional high-speed zips around curves and winding country roads.

Thoughts?

195/70-14 is the stock size. I would choose that size over the 185/70's. They would give a better ride and the spedo would be more accurate.

and... Just for future reference.... 195 is the width of the tire in millimeters. 70 is the aspect ratio or profile and means the sidewalls are 70% of the width, and the diameter is 14 inches. The 195/70-14 is 10 mm wider and 7 mm taller in the sidewall than the 185/70-14.

Fat tires rule!!!

Fyi compound is as, if not more, important than size when it comes to handeling. Just a thought.

195/70-14 is the stock size. I would choose that size over the 185/70's. They would give a better ride and the spedo would be more accurate.

Of course I should point out that "they would give a better ride" refers to tires of the same brand and model. Side walls vary from different manufacturers. But as a general rule of thumb, a 70 series tire will be more "compliant" then a 60 series.

Also 7mm may seem insignificant, but it's actually double that figure (think of it as 7mm above the rim and 7mm below the rim). 14mm in total is about 9/16 of an inch in overall height, or 18 feet of rolling distance resulting in a speedo error of 2.2%.

Yes, I AM a tire nerd.

Thanks everyone for the great info!

I checked last night and the Yokohamas I have now are in fact 195/70-14. As both of my '78's are 100% stock, I think I'll stick with those.

Another question:

Would you recommend 32 psi for this size and application?

Yes, I AM a tire nerd.

That makes two of us. (25 years in the business will do that to a person.) FWIW, I agree with pretty much everything posted here.

The recommended range is 28-32psi. I like the higher value because the steering is noticeably lighter at parking-lot speeds and more "nimble" at higher speeds.

Here's one for you tire gurus!

What does the "R" mean, for example in size 195/70R-14? Is it some kind of performance rating? Is there one that's better suited for Z cars than others?

Thanks again!

Radial

As opposed to:

Diagonal (bias)

or

Belted (bias belted)

R denotes RADIAL tires.

One note, the original tire specification was 175HR14 or 175SR14 or 6.45H14.4-PR if the owner's manual and Consumer Information pamphlet I have for the 71/72 are to be believed.

Edit: this is for the 240 not the 280

E

Edited November 11, 201014 yr by EScanlon