Tire size question

[AndysPlit]

Forgive me if this has already been addressed. I have the 82/83 turbo rims on my 78. They are 15" rims. Now it's time for new tires and I wan t to know which of these sizes would handle the best:

-195/50/R15

-205/50/R15

I want to switch from my 215/60/R15's. I believe the above sizes would improve the handling. However, I don't want the tires to look too dinky around the rim. Now I know there are other factors at play when it comes to suspension. I also know that brands may also make a slight difference. Honestly I'm looking at Kumhos on Tire Rack since I am on a budget. Oh, and the tires I plan to get must be H-rated.

Any suggestions on the sizes would be helpful. Thanks!

[Arne]

How wide are the rims? Both of the sizes you mention are rather small. If your rims are 7" wide, look into 225/50-15. If they are only 6" wide, look at 205/55-15.

[AndysPlit]

..........Good question. Sounds lame but I am not exactly sure how wide they are. Anyone know how wide the ZX turbo rims are?

[AndysPlit]

..........Good question. Sounds lame but I am not exactly sure how wide they are. Anyone know how wide the ZX turbo rims are?

....Nevermind. I found out. They are 6" wide.

[Walter Moore]

Yes the 280ZX turbo rims are 15 X 6 with a 10mm offset.

And by the way, the Tire and Rim association year book that I have lists both the 215/60/R15 and the 225/50-15 as being "approved" for use on 6" wide wheels.

Check the back spacing that you need on the front before proceeding. I think that on the 240Z a 225/50 would be close, if it fit at all. I do not know what the suspension looks like on a 280Z

(Particularly mounted on a 6" wide wheel. That will increase the sidewall bulge.)

[Arne]

Yeah, being only 6" with a 10 mm offset, 225/50s might give problems. I'd look into the 205/55s.

[AndysPlit]

Yeah, being only 6" with a 10 mm offset, 225/50s might give problems. I'd look into the 205/55s.

I was thinking about 205/50's. Would that be a better handling size compared to a 55? Would they look too skinny on my rim?

I'm not sure what is more relevant in terms of better handling. Should I be going by width of the tire or by profile?

[Arne]

I was thinking about 205/50's. Would that be a better handling size compared to a 55? Would they look too skinny on my rim?

I'm not sure what is more relevant in terms of better handling. Should I be going by width of the tire or by profile?

IMO, the 205/50s will look too small. They also have less load capacity, and so will be working much harder to support the car. The handling difference between the 50s and the 55s will be minimal, the 50s might be slightly more responsive to steering input due to the shorter sidewall. But being that the width is the same, maximum side grip will be very similar.

As for the width/profile question - width is somewhat more important for grip, profile for responsiveness.

[AndysPlit]

OK, that is helpful. Thank you.

I think I am going to stick to what I have now: 215/60/r15. I don't want to spend the extra money on 215/50's. Maybe someday.

I was afraid that the 50's would look too small on a 15" rim. It would work on an MR2, but not on a Z.

[Arne]

Remember that profile is a ratio. 50 means that the sidewall height is 50% of the width. So a 205/50 is pretty short, but a 225/50 is taller. So if you go wide enough the sidewall won't look too silly. Problem is that while a 225 will fit on a 6" rim, pinching it down onto a rim that narrow doesn't do the handling any good.

[AndysPlit]

Remember that profile is a ratio. 50 means that the sidewall height is 50% of the width. So a 205/50 is pretty short, but a 225/50 is taller. So if you go wide enough the sidewall won't look too silly. Problem is that while a 225 will fit on a 6" rim, pinching it down onto a rim that narrow doesn't do the handling any good.

.....Right. I failed to mention that the 50's would only look small if the width was smaller too. I'm sure 215/50's would look great, I imagine. And I agree with you that 225's are really pushing it on my rims.

I suppose I've been riding on an ideal size for my budget these last few years. I was excited to change it up, but not this time. One day I will try out the 215/50's.

Thanks again!

[Nissanman]

Here is a reference chart for Tyre Sizes both diameter and width, on specified rims.

It won't tell you if tyre "A" will fit your car when fitted to rim "B", but is a handy table nevertheless.

It is an old brochure but I believe the information is still valid:)