Optimal Size for tire on stock FB
 

I own a FB with a stock engine and stock 13" wheels. I am going to be purchasing a new set of tires soon and I wanna know what the best size to put on the car has some suspension work done and I really want to set it up as a cornering machine. I have heard that if you go too wide on the tire the sidewalls flex a bunch and give a really unstable feel. I have also heard that like 205 or 215 is as far as you can go with stock wheels but they don't give you the most performance in the corners and maybe a 195 would work better. Traction isn't really an issue with a stock motor. My car has 185/70R/13 right now and I have been interested in a set of Falkens 502 or 512(not sure which one, but one of these are not in production anymore) that are 185/60R/13. What size tire will preform best?

That's one of the eternal and unanswerable questions, too many factors to this.

1. Is it going to autocross?
2. What are your road conditions like?
3. Are you in hills, city or flatlands?
4. Your personal style has an impact.
5. Do you use it in snow?

Sidewall flex depends on sidewall height, brand, grip of the rubber, suspension modifications, condition of bushings.

Generally you get what you're paying for, and businesses like Tirerack have expertise, but they will need more info.

Steve

195-60-13

205/60/13 Toyo Proxes RA-1's. www.aimtire.com

THE best tire that's street leagal IMHO. To boot, it's an awesome rain tire too...It may as well not even be raining.

how much sidewall height difference is there when going from a 195-60 to a 205-60? Wouldn't you want to got to a 205-50, or is that too small of a sidewall?

well do the math...

195 X 0.60 = 117 mm
205 X 0.60 = 123 mm

There is a 6 mm sidewall difference.

205/50/15
my personal preference.

215/50/13

I guess you could say I have an aggressive/spirited driving style. I would love to autocross right now my car is almost set up for it, racing beat springs and sways frount and rear and tokico blues, LSD/Disc rear end swap, roll bar, sparco seats and five point harnesses.
I live ten mins. from seattle so its a mostly urban enviroment lots of hills, lots of rain but I drive a different car in bad weather situations unless I want to get sideways then I drive it in the snow and rain. I have thought about the RA-1 and I am not sure how long they will last mileage wise and they are almost out of my money range but have read they have an amazing level of grip. More realistic right now are the Falkens 512 or 502, Sumotumo HR200 or Toyo spectrums

Out of 205,195, and 185 width which size handles the best in the dry conditions?

Out of 205,195, and 185 width which size handles the best in the wet conditions?

The reason I am asking this is there is an ideal contact patch where the tire meets the road and the right amount of pressure is put onto all the tires, and the wider tires will have less pressure or force pushing down but more contact area to the road. you could lose cornering performance or gain performance idk, but is a couple millimeters difference worth changing the size I buy?

ditto

Another thing to consider is that the wider your tire, with the stock wheel width, you get a pinching effect, where the tire bead is substantially narrower than the tread width of the tire.

Why not upgrade to a bit taller and wider wheels?

If I may semi-hijack the thread here, I'd like to ask a specific question about sidewall height. This is in regard to the difference between the stock GSL-SE size of 205/60-14 vs aftermarket 195/55-14. I know that the 195/55-14 is 5.2% to fast for the speedometer and that when the speedo reads 60 I'd be doing 57. I think a shorter sidewall would give a slightly harsher ride. I think it might make turning more crisp.

Has anyone tried both of these sizes on an SE and have anything (negative) to say about the 195/55-14 on the stock alloys? I imagine any answer would be somewhat applicable to 13s too.

ill help you hijack this thread with irrelivent information:
i can say 195/50r15 makes the car feel like a laser guided rotary death missle with a bent for annoying GM products with her angry buzz.
of course the ride is harsher as well (stock springs, 1983 OE shocks *ugh*, dumpster scavenged winter tires with leaks)
i can imagine that the 14 would be similar, though the rim you put it on is critical as someone mentioned earlier. 195 is about equal to 7.5", so a 7inch rim really helps.

sidenote: if you want widebody: get old supra or celica gts 14x7 rims. the hob bore is identical, and the holes are big enough to clear the studs (supra is 4x114.3) but the offset puts the tire an inch out the fender as i recall.

hijack! now gimme all your money!

Now that I've asked my question I'll add what I have experienced not on RX-7's. I've used 205/50-15s on a 6.5" rim and liked them just fine. For street use it would not be easy to tell the difference between that size on a 6.5" rim vs a 7". On the track it would be slightly more apparent, or so I've heard.

Back to 14s, I've used 195/60-14s on 5.5" rims, which is the width of SE alloys I believe, and that size worked fine. I know others have very successfully used 195/55-14s on 5.5" rims on Miatas and it works great. I was just wondering if there was anything different about SE's where this Miata knowledge wouldn't transfer over. Would it make my wheel gap look stupid on stock suspension height?

You can't put SE wheels on yours anyhow. Different bolt circle diameter.

notveryhappyjack has 13s on his FB. I have 14s on an SE I just picked up recently, which is an FB like the thread title says. Just a bit different on the rim diameter than the original poster was specifying. I've been thinking about starting my own thread for a few days, but my questions and his have some similarities in what we are trying to figure out so I thought I'd try to get more responses for both of us here.

Is wet weather a consideration?

13's or 14's I would think the same logic would apply to both sizes so I don't really mind the thread jack. I believe the stock 13' wheel is 5' or 5.5' wide so putting a tire that is too wide wouldn't make much sense on such a stock low HP light weight car.

Aussiemg, yes it will be raining everyday for the next seven months.

I didn't even think about this but does different size profile change the speedo reading?

Yes, different size profile will definitely change the speedo reading.

Any SE owners here run 195/55-14s?

The stock rims on either an SE or non-SE is 5.5 inches.

With that rim width, going higher than 195/60/13 makes the sidewall bow out quite a bit and has an adverse effect on handling.

I've found that the best tire size for handling and acceleration is 185/60/13. That combo is an inch shorter than the stock tire and equally wide, making for a stiffer sidewall which improves lateral grip. The sidewall on that size tire is not bowed out on the stock rim, which is a good thing. Additionally the shorter overall size improves gearing for better accelleration. The difference was quite pronounced on my SA when used in solo applications.

I agree with your statement about the 5.5 rim width on both models, but you are aware the SE owners manual states 205/60-14 is the OEM fitment, yes?