I'm planning on going 16x10 on the rear of my Miata. I am terrible with tire sizes and I'm having a difficult time finding a good tire.

Here is what I'm after:

1. I want a full tire, I don't want to stretch a narrower tire. I don't like the look. I want some sidewall.
   
2. Initially, I need a street legal tire, but an aggressive one that I can autocross with until I figure out what to do about race tires. But if you have suggestions for race tires, post them up too.
   
3. The front tires will be 8 or 9's, so hopefully the suggestion will have sizes that will fit front and rear.

Thank you for your assistance.

 

Oh would I love to have something that will fill up a 16x10 in a decent street tire! Bring on the 285/30-16s! Sorry to say I have looked and looked and nothing exists...

Is there 16x10 wheels that are 4x100?

I'd be thrilled to have a 245 or 255/ 40 -15 to fill up 9 wide...

 

You could go 12 wide with a set of Perellis.

Pirelli "P Zero System"

345/35ZR-15

140 Treadwear - tread 13" wide!

$751 each

http://www.tirerack.com/tires/tires....R50A&tab=Sizes

 

That would be awesome, but I really don't think 12" wide tires would fit in the wheel wells, I may be wrong. I am told that 10's will fit no problem, but I won't know for another month or two until the body work is done.

 

I am running 245/45r16's in back.

 

On 16x10's?

 

Is this for the street, or the track?

This is a 15X10 rim on a track prepped Miata



Bill S.

 

No offense intended Bill, but that is a picture of what I don't want. I really don't like the look of a tire that is stretched to it's limit to fit a wheel it wasn't intended for and I've never really liked the rim sticking out. Again, just my personal taste.

I'm a muscle car guy, not an import guy. I know, it's a miata. But that doesn't mean I can't bring some muscle car aspects to it. Like the wide body kit from Monster Miata and some thick meats all around (and obviously a v8).

Initially, I'm looking for something for the street that I can use for a bit getting used to the car and maybe a little autocrossing.

I haven't had an issue finding race tires. They seem readily available.

 

No offense at all, I too prefer a rim tucked in to the body lines. It has been my experience with street driven Miatas that a 7 or 8" rims is about as wide as you can safely tuck under the stock Miata bodywork. While I have a few friends with custom widened rims on a road race prepped Miata, I do not know of one of them who is running wider than a 9" wide rim, and at that, they have massaged the wheel well openings quite a bit to prevent clearance issues. The above picture shows a 10" rim, at a +2 offset from stock, which is as tight as you can go on the inside without clearance issues. A 10" rim does not fit under the stock wheel arches, not even when pointed straight, let alone in a situation where you have to turn on to a side street....

That is my point for posting the above picture and asking your intentions for the fitment of the rims/tires.

Bill S.

PS: My ERA 427SC Cobra does not even use a 10" rim in the back, and I'm running a 295x15 on the stock spec 9.5" pin drives

 

Totally understandable. Don't get me wrong, I really appreciate the feedback and any information that you can provide. I guess I should have made it clear that I will not have stock fenders. I have the Monster Miata wide body on the way. I talked to Martin and he said 16x10's are no problem at all. I just didn't realize it would be such a problem getting street tires for such a setup.

 

Not that would look good at least. I say stick with a 16X7 or a 16X8 and perhaps a 205/45/R16. Backspacing will play a key roll, as you want around a 5-5.5 back spacing (38-40mm offset) to get enough clearance along the inner wheelhouse.......


Bill S.

 

Bill 38 to 40 mm offset really? I thought that would hit. My 15x9s with a 36 mm offset hit at full lock so I spaced them out 5 mm.



I hate this shot:



If the tires had at least an inch more tread on the ground I could live with it but to me the thing looks like a girl car on the 225s.

Now this is what I'm talkin about!

 

Hmmm, finding tires to fit a 16x10" wheel is a tough one.... even without the limitations of the NA/NB chassis. Back when I was building a C Prepared autocross car for SCCA Solo (way back 1996!) that was a popular wheel size for that one racing class, and you could get relatively inexpensive wheels from Real Racing Wheels, shown below in 16x10" on one of my buddy's C P Firebird. They will even make that size in 4 lug, which is rare.



But the tire choices for a 16x10 sucked way back then and they are only worse now. For these CP Racers, they use real competition racing slicks from Goodyear, Hoosier and now Avon (Goodyear killed their entire radial slick and DOT R-compound radial lineup in early 2013). For DOT Radials there are some wider Hoosier A6/R6 tires in 16" left (widest A6 available is P275/45ZR16), but there is nothing for a street compound tire (140-200 TW) available beyond about 225mm in 16" anymore (a few 255/50/16's are still around, which was an old C4 Corvette size - but it is very tall for a Miata!). For a 10" wide wheel you'd normally be looking at a 275-295mm tire width, in case you were wondering.



And for an NA/NB Miata, you are stuck with about a 225mm tire unless and until you are willing to cut the fenders and add flares.



One of my NASA TT3 competitors has an LS1 Miata and uses a 15x10" wheel and 275/35/15 Hoosier tire, but it has been flared, as you can see above. That 275/35 Hoosier is nearly perfect for use on a track-only or autocross-only Miata, but there is no street compound tire equivalent, nor another choice for a DOT R-compound. People that build around that race tire have that single tire choice, and that's it. Scary.



Tire diameter/height becomes another serious issue you have to worry about when you get beyond the somewhat narrower 15" wheel choices, even after you have cut and flared your fenders. We're running into the tire height limits on our LS1 Miata swap, which we are building around a 285/30/18 (a size which has lots of street and R-compound choices available). This 285/30 tire is super short for it's width, but at 24.9" tall it is still almost 2" taller than the stock 23" Miata tire sizes. Take that 24.9" tire height, then lower the front suspension ride height, and boom - tire meets upper frame horn, as shown above. We will have to modify the upper frame structure to clear this tire!



So realistically, on an street driven NA/NB Miata you are looking at a 225/45/15 on a 15x9" wheel as your widest practical tire fitment, this side of flared fenders and/or frame horn mods. That the tire and wheel shown above, on one of my my employee's NB Miata (using the RS-3 tires and 6UL wheels) and you are very limited on tire selection there, too. And they only fit due to the big stretch of that 225mm tire onto the wide 9" wheel.

The ability to fit tires wider than 225mm is an age old problem on the NA/NB, and normally you are looking at extensive fender rework to get more than a 225mm width tire in 15" diameter.

 

I appreciate the feedback and your personal experience in the matter. So to try to help narrow this discussion to help me directly.

1. There are new front fenders on the way that are "wide body" and was told that 16x10 would fit no problem. Even though 16x9 will probably end up on the front due to clearance for turning.
2. The same "wide body" kit comes with rear fender flares that will require cutting the rear fenders and molding these into the body. Once again told that 16x10 would be no problem.
3. I don't want 15's, I just think they are too small. I may consider 17's if that opens up more possibilities. But bigger than that is out of the question. Just too big for me.
4. I am planning on running Panasport C8-16 racing wheels (3 piece design).

Can someone please help me narrow down the selections (street and track) for this package? If you know of any tires for this size wheel, please list brand, series and sizes and classify them as track or street. I will update the first post with results for anyone that may be looking in the future.

The body kit is in production and will be shipped in about 3 weeks. At that point, it is off to the body shop. This information will not stop that process, but I would like to at least get this decision underway.

 

Sorry Greg but me and many others have been down this road and searched till are fingers are sore. There are no street tires available for 9 or 10" wide wheels beyond 225s that are not too tall for the car. Doesn't matter if you run 15s, 16s or 17s but most folks feel 17s are too big for A or B Miatas anyway. If you can live with the monster truck look there are a few 35 series 17s out there that are not too bad. Toyo R1Rs 245-35-17 but not exactly a great DD tire.

 

I am using this size on the rear without any fender modifications on a 7.5" rim: http://www.kauffmantire.com/tire/236800.html

 

^^ link is blank for us what size are you using?

7.5 is way to skinny for my taste though. I could live with 255s on 9s but would love 285s on 10s and wouldn't care a bit if they rubbed at lock or hung out just a hair from the wheel arches.

 

A great racing engineer once told me: Always build a race car around the tires you want to run.

If this car will see any sort of competition (I think your opening post hinted at that?), then your tire selection should be driving your wheel size and even the wide body/flare options, not the other way around. Why? Well for any sort of competition use, finding the optimum tire is the number one priority because tires make the most difference in lap times. So if you are building a car for autocross or track use, pick the tire first, then the wheels, then the bodywork necessary to make it work. The class rules, racing uses and other factors will drive what tire width you need, then the wheel diameter is next (driven by tire selection first with a small nod towards clearing the rotor size you need then the tire height last).


14" rotor fits inside this 18" wheel, but only just. We tested 15" rotors and calipers, which were a "no go"

What brake rotors are you using? If it will see track use the stock rotors might not cut it, especially if you have added a lot of power over stock. This rule of thumb usually works for wheel diameter:

11" rotor = 15" wheel
12" rotor = 16" wheel
13" rotor = 17" wheel
14" rotor = 18" wheel

Racers will choose the smallest wheel diameter that clears the brakes they need for the racing that they do. Why? A smaller wheel diameter gives you less overall weight in the wheel, by a substantial amount. The only time you ignore this rule is when you cannot get the proper width tires for the wheel diameter that was driven by the rotors. It often makes more sense to upsize the wheel diameter to get more tire choices.


Tire height/diameter can affect final gearing as well as bump travel clearance to the fenders or even the frame

This is painfully obvious with the current state of 16" tire options, which absolutely suck. Anything beyond 225mm is going to be way too tall and the choices are VERY slim. You are not going to find a street tire to fit a 16x10" wheel, sorry. It is a big foot/unicorn/5 leaf clover tire.


Rotary forged/flow formed/pressure cast Forgestar F14 in 18x12" is relatively light at 22 pounds

Tire weights do not vary much from brand to brand (in a DOT radial), but wheel weights can - the type of wheel construction makes for most of the differences. The lightest wheels tend to be fully forged 1-piece aluminum, but they also tend to be the most expensive. Next heavier in line are 1-piece flow form/pressure cast/radial forged wheels (this is the same process with 3 different marketing names), which tend to be the best lightweight/cost ratio wheels (Enkei, Forgestar, WedsSport, etc). Next heaviest in line is a 2-piece or 3-piece wheel (and often the most expensive), and last place is a 1-piece gravity cast wheel (at least it is usually the cheapest). Steel wheels tend to fall somewhere from a tick lighter to as far as "much heavier" than gravity cast wheels, but can be the cheapest by far. Almost nobody uses steel wheels for road racing use outside of Lemons racers or NASCAR.

Since you have the bodykit on order, I'd wait and make the wheel selection after that is installed. Because that is now going to be the limiting factor for wheel and tire width as well as tire height. Let the wheel diameter, wheel brand and style come later, as the wide body kit is likely a pricy piece of kit that you won't want to alter to fit this mythical 16x10" wheel and nonexistent tires.



But if the wheels and tires are just part of a style, look or fashion statement, ignore everything I just wrote. But you still aren't going to find many/any tire options for a 16x10" wheel that will likely fit.


some Corvettes used 16x9.5" wheels from 1984-1987, then 17x9.5" wheels from 1988-1996 (shown)

I just did some searches on TireRack.com (you need to spend some time on there yourself) and looked for anything in 255mm (which is about as narrow as you want to go on a 10" wheel), 265mm and 275mm widths in 16" diameter. Here are the ONLY tires found:

• 255/50/16. This was a C4 Corvette size "back in the day" (1984-1987), so we will still see a few sizes for a little while longer. Looks like there is only one street tire option left, in the BFG Sport Comp2 ($134) with a few other options being R-compound DOT race tires. This is a 26.1" tall tire, a full three inches taller than the stock stuff. That could really cramp the space to the wide body kit, and especially the front frame horn (as noted in my previous post) under bump travel.
• 265/45/16. There are two R-compound sizes from Kumho: The V710 and the W710 wets (which has been discontinued).
• 275/45/16. Again, only race tire options (4) and 25.8" tall (tall!)

That's all she wrote for those three widths in 16" diameter. That 16x10 wheel is simply a doomed size for a Miata unless you don't mind running a tall race tire or having all of ONE street tire option (that is still very tall). Don't take my word for it, go on over to TireRack.com and click "Tires" and then "search by size". Pick the widths the will even fit onto 10" wide wheel (255 to maybe 295mm), pick 16" diameter, and then go through the dozens of iterations in aspect ratios (from 30-50) to find that there is almost nothing left in 16" wheels anymore. Pretty much if TireRack doesn't carry it, it doesn't exist or you don't want it.

Sorry...

 

Hm. That sucks.

The whole reason I started the thread is mainly because I wasn't convinced I understand/believed what I was finding. But unfortunately, the input I have received here backs it up.

So, that takes me to the two remaining options.

1. Reconsider the 15" and 17" options.
2. Look into custom tires being produced.

Since option 2 is possible, it would be ridiculously expensive. I just don't think would be a smart thing to do. The only time I would do that would be for a show piece. And since the issue is just street tires, I don't think that is the way to go.

So, back to the 15" and 17" options. Since for some reason it looks like I broke tirerack.com's tire size page, I will look into that later. (I was cranking through there and on about the 30th combination, it stopped responding)

 

Lots of cars came with 17 x 9s so there are more options for that size wheel but for us it's really hard to find a short enough tire in 17s.

For most Miatas a 23" tall tire is perfect but of course ride height, wheel opening size and what you are going to do with the car are huge factors in choosing tire size. There are lots of choices for 255/ 40- 17 but they are very tall at 25". I have been considering going that way for street tires to gain an inch ground clearance but I know there will be clearance isses to deal with at that size.

Bottom line is there are no good options for any street tire in any wider size for these cars. I think we should all get together and lobby a tire company for one good street / track tire around 250 tread ware that is the right size for performance Miatas. 255/40/15 would be perfect on a 15x9 or 15x10 wheel IMO.

 

I am going to be looking at 15's and 17's. It looks like there are a lot more options when you get to the 17's, but I don't know if I will like the looks or the performance. I am going to wait until the body is all ready and go from there. With thus body I should be able to go with whatever I choose. Clearance shouldn't be an issue, but we'll see.

 

So Greg where are you at on this? I've opened the can of worms again and researched till my fingers are bleeding. Same game as always the good wheels are either the the wrong offset or too only 7" wide and no tires for them anyway.

 

I have decided to wait until the body kit is on and the wheel wells are finished. Then I can do all the measurements and see what will fit up in there. If I can go with 17's and get them up in the wheel wells, I may go that way. But only if they will fit up in the wells. I don't want to be riding high on wagon wheels. But we'll see.

 

Dumb question but what makes an rcomp? is it treads? I recall seeing a Dodge big monster hemi sema car something where they put the Mopar logo on carved into the slick. would that make a slick available for use on the street i.e. carve some treads into it? I assume rubber is gumball, but what about a hard compound with treads? Assume that may have some street civility?

 

I have wondered that too and near as I can tell Rcomp is about as useful as the definition of GT on the side of a car. The problem is the tread wear ratings are determined by the manufacturer and they are usually about as accurate and consistent as HP ratings from one manufacturer to another. They do the testing and rating on their own and there is not a lot of cross testing from manufactures to keep things consistent in the industry. The good news is it really only comes up with SCCA guys trying to stay in STS class or one of the other fairly stock classes but still try to run sticky tires.

Anyway to answer your question near as I can tell it's a tread wear rating lower than 40, not rated at all, or tires not DOT approved for street use AND the manufacturer wants to call it an rcomp tire. But I could be completely wrong too because I never could find a better answer.