Wheel change 16" to 15" what's best?

[Silvia]

I'd like to try to replace my 16" stock wheels with 15 " to get the ride a bit more compliant on the 2002 NB8C....Can I use earlier NB stock 15" wheels that look similar or is there some fit issue? I like my stock alloy look.
I'm wondering what happens to the stock 15" wheels when guys fit aftermarket ones?
Would a Kumho KU31 in 15" 50 series be a good choice to fit.....or is it better to try to get wheels and tyres already fitted secondhand?

[BadBong]

Might want to check with someone to ensure that the stock 15s fit over your NB8B brakes.

KU31s in 195/50/15 would be a good start for your 15" wheels.

I think most people change their stock wheels for a different look. Only the hardcore trackers would go get something lighter than what we've got in stock form because our stock wheels are quite light already (and they're free!)

[NitroDann]

they do fit.

Dann

[sailaholic]

Cheaper generally to get with tires just check how old as you have already discovered ;-) .

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[Silvia]

thanks guys
Are the stock 15" wheels 7" wide?
195/50 15 was suggested tyre size, are there any other options that are legal , like 205/50 or...?

[rvlovell]

Just a heads up regarding KU31's, they are quite a noisy tyre. If your after comfort you might find Michelin's PP2's a better option, I found after changing to them in my NB that my ride was quieter and softer as well as having substantially more grip in the wet.

Another thing to consider is if the tyres you have are getting old the rubber hardens making for a bumpy ride. Also check that your tyre pressure isn't to high, try dropping to 30 pounds a corner if they are higher than that.

If your going standard 15's see if there is someone near you with 15's and go for a ride to compare before forking out the money.

[hks_kansei]

thanks guys
Are the stock 15" wheels 7" wide?
195/50 15 was suggested tyre size, are there any other options that are legal , like 205/50 or...?

No, factory NB8A wheels are 15x6 with a +40 offset.
As you mentioned, stock tyre was 195/50/15


You probably can fit a 205 onto a 6" wheel, but I don't think it's recommended.
The 205s slightly baloon on my 7" wide wheels, so I think they'd be a bit wide for 6"s
Again, check with the tyre manufacturer. I know Toyo used to publish a list on their website that showed tyre sizes and the approved/safe wheel sizes for them.

[sailaholic]

205 50 is also ok.

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[Silvia]

Having a look at the tyre calculator on Miata ... the 195/50 15 is only 1809.6mm circum.
that's a lot smaller than the stock 16" I have now(205/45) at 1856.4mm would that be legal?
Even the 205/50 15 is 1841mm circum . so 15mm smaller. Was hoping for a bit bigger......

[Guran]

Tyre diameter is the important criteria as far as legality is concerned (not circumference). Alternate tyres must be within 15mm of the original tyre diameter. With OEM of 205/45R16 ...

16"x6.5" options
195/45R16 8mm smaller than OEM
185/50R16 2mm larger than OEM
195/50R16 12mm larger than OEM

15"x6" options
195/50R15 13mm smaller than OEM
205/50R15 3mm smaller than OEM
195/55R15 5mm larger than OEM - this might be a suitable choice
185/60R15 13mm larger than OEM - another possibility but with NA6-width rubber!

(205/55R15 17mm larger than OEM - not legal)

You'll also need to make sure the load & speed rating of your replacement tyre matches or exceeds the OEM spec (83W).

[Basho]

Heres a tyre calc you might find handy

http://www.rimsntires.com/specs.jsp

[Silvia]

You've done a great job Guran, and I got all excited at some of the options you found.
50 series 16" would solve it....but I can't find a decent 185/50 or 195/50 in 16" tyres in reality.
In the 15" 50 series same story. If not wanting to go smaller, there's really nothing available...205/50 15 is only a bit smaller 5mm but a KU31 costs $120 before extras.
Plus buying wheels of course...
That slightly too big 205/50/16 Kumho KU 31 is looking better and better, specially at $104 and with bigdog's recommendation.

[Charlie Brown]

Silvia,
I have been following multiply threads you have started on the subject of ride, revs, tyre sizes, gearing, handling, 4WD vs RWD, etc. for some time.

I did own a 2003 NB8C for three years from new and find it difficult to accept that the ride is rough even on the poor roads in AU.

I’ve looked at advice given by those who have owned MX-5’s for long periods of time and not wanting to sound nasty or put you down but I think maybe you have chosen the wrong car.

The MX-5 is a light weight, free revving, short wheel based spots car designed with great handling and a sense of speed, even when you’re not going fast. It has never been or is intended to be, a smooth riding, low revving GT tourer.

Your desire to change to 15” wheels with a higher profile to provide a smoother ride is fine provided you accept the legalities of the change, as others have commented. I know of Club members with back problems who have change to a 50 profile tyre and they reported a marked increase in comfort. Others here have commented on selecting a tyre with softer sidewalls that will get you some improved ride but at the expense of handling.

But maybe you are looking in the wrong place to improve your ride? If your car is still using the original shock absorbers then I suspect they’ve had it and you’re riding on the bumpstops. If so it won’t matter if you fit 15” rims with a 60 profile, it will still ride roughly.

Can I suggest you make yourself know to members of the QLD MX-5 Club and go for a ride in someone else’s NB8B/C to see if there’s any difference in the ride. It is probably the cheapest option you can try.

[sailaholic]

I'd think your 15 inch tire size might be high. Try calling option 1 garage and see what the do a 205 50 fitted for.

Also agree with cb, go ride and talk to people, you will learn far more then multiple forum threads on very what are very common and well discussed topics. no offence meant, nor anything against forum discussion.

If you can bare to drop down from the "pinnacle" of an NBC, :-P I'll take you for a drive in an na with 205/50/15 and koni shocks.

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[Silvia]

Thanks CB
I don't think I've chosen the wrong car, in fact I'm lovin' it! I'd better, as the other car,Forester turbo, just left with the new owner
Put simply, the tyres on Silvia are G111's and 6 yrs old and nearly spun me out on a wet roundabout . Investigation showed the tread is about 80% good but they are too old and hard - like me
OK I'll buy new ones, and everyone agrees the roads here are rough, so it can dance a little on it's 45's on corrugations. It's not major, but when you are looking at spending big notes , you look at the options...or you should. One option is to change to 50's and have a little more wall to flex, maybe cruise at slightly lower revs. Ah but then it gets weird . 50's in 16" are a problem due to availability,legalities,prices etc.
A change to 15" is suggested...yes they are cheaper tyres but everyone says 195/50 15 is the go but when I check they are way smaller than the current stock size
So , no problems just research into improvements.....made humans prevail you know The improvements I've made through this and other sites are great too...
I can always go back to new stock 205/45/16 size and live happily ever after....
then again..