I bought a set of ET 14 x 6 3/4 rims and want to install a set of BF Goodrich Radial T/As in 215/60/R14 in my 1980 with stock suspension.

Will this size tire fit OK without rubbing, or should I step down to 205/60R14.

Thanks.

 

Too big, 195/60r14 would be perfect. I run a 215/60r14 on the back and a 195/60r14 on the front. It steers way easier with the 195's than it did with the 205's

 

With a 12a I would stick with 195's all around, 215's would kill some gearing in the back (taller and wider). 195/60r14 are about the same diameter as the stock 185/70r13. Invest in a "great" quality tire, focus on quality not size.

 

Yeah, I've thought about that.

The 215's are .41 inches larger in diameter than a 195/70R13 tire, which is less than half an inch.

Assuming the 195/70R13 are close to factory spec, then based upon tire size and gear ratios, I'll actually be running 1.3 mph faster at 3500 rpm (75.3 mph) with the 215's, than what my speedo says with stock tires (74 mph).

The biggest variation is only 2.5 mph difference at 7000 rpm redline (150.5 mph vs. 148 mph). So the difference is pretty marginal and could even be affected by tread depth.

The larger tire will put a slight draw on rear wheel torque, but I think it will be negligable initially. However, I plan on removing my stock exhaust system and replacing it with an RB road race header and dual inlet Powerpulse muffler. So I'm hoping that the additional horsepower gain by improving the exhaust system, should compensate for the slightly larger diameter tire.

I'm also adding new shocks, but not coil overs. So the only llimitation that concerns me is clearance around larger tire.

 

I got 215/50/13s all around. Sits nice in back with my wheels. It's to big in front though. 205 all around is good. That way you can rotate them too.

 

Question...

Why are 215's too big in front? Do they rub, or is it handling and feel?

 

They rub on the strut tower a tiny bit, I mean like barely even touching. Drove with them for awhile though now.

 

Do you have stock 13 inch wheels running a 50 profile?

If so, I'd figure that the lower profile puts your tires near the bottom of the strut, but I think the struts incline inward towards the top.

If that's true, then my 14" rims and taller profile (60) should raise it up a little more and give it more clearance.

What do you think?

 

It's the strut seat and lower spring coils where the interference occurs. The spring seat is notched on the tire side of the strut for increased tire clearance. The seat diameter at that point is 3-3/16", taking the notch into account. Overall diameter of the seat is 3-7/16". Doing a little math, going coilovers should show a net loss of 1/32" of clearance. I suspect my math or measurements are off somewhere, hopefully Billy will step in and clear this up, LOL.

What everyone must keep in mind is the backspacing differences between wheels. Maximum backspacing, including tire bulge should be no more than 5-1/4", (non-SE suspension), to clear the struts. This measurement does not take into account any needed clearance/interfernce with the sway bar, caliper or other stering/suspension components.

 

Holy F&^K dude, don't listen to 25 years of experience in the industry and go make a mistake based on looks. Stock size is 185/70r13!!! Automatic +1 concept is 195/60r14! Go here and punch the numbers for yourself http://www.miata.net/garage/tirecalc.html

205 or 215 will make steering tough, 195's all the way around will work awesome! Don't ask for the advice if you don't wanna follow it!!!! Get a great quality hr or vr rated 195 all the way around and your car will be well balanced and handle great!

 

But your advice is metric. What's the formula to convet to standard advice?

I run 195/60/14 on all four corners. It looks fine, handles good, speedo's right on, and fitment is good. The fronts have very little clearance on the spring seat, to the point that I was concerned about tire swell when I hit a bump, but that's proven not to be an issue.
I personally wouldn't run anything bigger than a 205/60/14 MAX.

 

FYI...there is a lot of experience in this club, but the problem is "advice" is like *** holes. Everyone has one and thinks there's is the best.

Right now there are 3 other threads that contradict a lot of what you said, so back off and chill.

I don't want opinions, I want facts. I want actual experience and emperical data so I can do my own analysis and make the best choice for me.

If it turns out unsatisfactory, no sweat, it's my problem and nobody else's. I'm out a few extra bucks and buy another set of tires.

So keep the uncalled-for flaming to eharmany, classmates.com, or whatever other social network you hang out.

 

SEs ran 205 60 14 stock, i've never ran anything bigger than 195s in the front tho. 215 in the back adds too much traction for a stock car. but it looks bad ***. the previous owner originally put 185 in the front 195 in the back, and i've only used junky tires. but i get respectable traction from them, even in the rain. not bad for 25 dollars (215 60 14 good condition) i installed them myself. then i had to pay 35 for the 195 fronts... 70 for 4 tires isn't too bad right?

 

No, not the stock wheels. They're 13x6 with 15 offset I believe. There's a pic of them in this thread https://www.rx7club.com/showthread.p...hayashi+wheels. I'm not sure on the 14s, it might help a little bit. I would personally go with 205/50s all around though.

 

Use this, it'll tell you exactly how much wider/taller/ good fitting etc. you ties will be.

http://www.rims-n-tires.com/rt_specs.jsp

I always plug in the stock dimensions on the left, and on the right, I put in the width I want ( I went with 205s) then the rim diameter and width, and played with profiles until I got the diameter as close to stock without going over (I prefer shorter gearing over taller, but stock matching would be best). This will give you a good idea of what profile you need to run with your desired tire width and wheel diamater.

 

...too MUCH traction?...

What's the downside to too much traction?

 

Anyone know the offsets on the original stock and optional aluminum "waffle" rims?

Looked around the archives and the FSM, but could not find this info. The wheel size system used in the FSM (5 1/2 - JJ x 13WDC) appears to be archaic - - doesn't match what I see in modern wheel catalogs.

 

Great help, 87 Turbo...

That calculator is a terrific tool. I could put my stock wheel/tire design and compared to my new wheels and tires.

With my wheel design & offset, it said I will be 100% clear of the suspension and have more room than OEM, with the 215/60R14s that I ordered.

It will fill out the wheelwell by extra 5 mm and said this is acceptable for most cars. It will stick out a 25mm/1 inch and to make sure that there is enough room under the fender. Other than that, it's OK.

I'll try them and see how they fit and perform. If they don't work out, then I'll have to switch to 205's.

I saved that calculator to my favorites and suggest others do so as well.

Thanks.

 

Remember to check the specific tire width spec of the tire you buy , not all 205's or 195's have the same width for a given size ..... ie BFG are wide , Sumitomo are narrow. so a 195 BFG is about the same as a Sumitomo 205 if you look at the specs .

Tirerack web site has pretty good tire width specs for most tires

 

Divindriver,

I have an extra set of the waffle wheels and just measured them.

Here ya go:

13" diameter
5.5" width
15mm offset
97mm/3.8" backspace
4x110mm bolt pattern = 4 x 4 1/2 bolt circle

Hope this helps.

 

No problem.

 

Exactly what I wanted to see; thanks.

You just saved me having to pull the spare out tonight, heh.

 

I still don't get traction with my 215s

 

Good luck with whatever you pick, I was criticizing the fact that you seemed decided already. I "made" the mistake of mixing sizes with a "cheap" tire and I "know" the 215/60r14 is too big for the stock 12a. I was trying to passionately get my point across and get you to listen and perhaps weigh more information before deciding. So if you took offense and ordered the big tires anyway, then that's up to you. Hopefully you bought a good brand and rating.

 

Why wouldn't you go with 195s and keep your speedo the same? I'm rocking 195/60 right now. No rubbing, but I wouldn't go any bigger. They are nice and wide, without being rediculous for the street.

FYI-you can run a 215 on a 13" rim but I wouldn't think of trying it on a 14. a 215/50 13 is short and can clear the suspension. a 215/60 14 is a completely different story.