Terminology

Erwino · Postby **Erwino** » Tue Feb 21, 2006 12:22 am

i just bought a 1998 NB mx5

http://img48.imageshack.us/img48/3338/picture0017ea.jpg

now id like to upgrade the wheels

i few things i dont understand,

when people say 225/50R15, im guessing the 225 is something to do with tread. the 50R is something to do with how low profile it is, so 40's would be extremely thin around the wheel and like 70s or 80s would be big bulky. and the 15's are the wheel sizes like 15".

what are these exact measurements?

whats the 225 mean
whats the 50 mean in relation to the low profile thing?

what are offsets?

what does scrubbing mean

what does rolling flares and lips mean?

at the moment ive got the stock 15" alloys with 195/50R15 goodyear tyres.

how much do these stock alloys weigh?

whats the max size i could get on my mx5 without causing any damage and losing too much handling.

what sorta weight should i be aiming for per rim.

i really like the 5-6 black spoke design with the chrome lips.

also i dont know if u can tell from the picture, but those disc things that u can see directly behind the wheels are extremely rusted, how would i fix this, and what sorta price am i looking at

Matty · Postby **Matty** » Tue Feb 21, 2006 8:40 am

There are a million books and websites to explain this, but here goes:

225/50R15

225 = tread width in mm
50 = aspect ratio (the ratio of height to width, in percentage) ie, this tyre has a sidewall 225 x 50% = 112.5mm high
Note that it's not an absolute value, ie, a wide 40-series tyre can be taller than a narrow 60-series one!

R = radial construction (as all road tyres are now)

15 = rim diameter in inches.

OFFSET is the distance between the mounting flange of the wheel and its centreline. Lower offset means the wheels are mounted out wider.

SCRUBBING usually means that the tyre is hitting this guard/fender liner at some point in its movement range.

ROLLING/FLARING is the modification of the guards to prevent scrubbing...

The OEM 15"s are about 6kg I think... In the case of a light car like the MX-5, lighter is always better, as a wheel is unsprung weight, and more of this leads to a really bad ride quality.

I woudn't want to go bigger than 16" or the wheel starts getting too heavy (unless you have megabucks for forged rims)

Those metal discs behind the wheels are the brake rotors. Don't worry about rust on them, they're cast iron and that's what happens. The working surface of them will be polished clean the first time you use the brakes of a day.

Erwino · Postby **Erwino** » Tue Feb 21, 2006 9:47 pm

Matty wrote:There are a million books and websites to explain this, but here goes:

225/50R15

225 = tread width in mm
50 = aspect ratio (the ratio of height to width, in percentage) ie, this tyre has a sidewall 225 x 50% = 112.5mm high
Note that it's not an absolute value, ie, a wide 40-series tyre can be taller than a narrow 60-series one!

R = radial construction (as all road tyres are now)

15 = rim diameter in inches.

OFFSET is the distance between the mounting flange of the wheel and its centreline. Lower offset means the wheels are mounted out wider.

SCRUBBING usually means that the tyre is hitting this guard/fender liner at some point in its movement range.

ROLLING/FLARING is the modification of the guards to prevent scrubbing...

The OEM 15"s are about 6kg I think... In the case of a light car like the MX-5, lighter is always better, as a wheel is unsprung weight, and more of this leads to a really bad ride quality.

I woudn't want to go bigger than 16" or the wheel starts getting too heavy (unless you have megabucks for forged rims)

Those metal discs behind the wheels are the brake rotors. Don't worry about rust on them, they're cast iron and that's what happens. The working surface of them will be polished clean the first time you use the brakes of a day.

the front brake rotors are alright, still ugly looking with bits of rust on it

and the back wheels the top half of the rotor is same as the front wheels but the bottom half of the rotor is still rusted up heavy. like the outside of the circle i mean*.

whats the maxium offsets for 16's
and whats the maxium offsets for 17's

also where do you get low weight wheels from?

Craig · Postby **Craig** » Tue Feb 21, 2006 9:57 pm

Mania sell some light weight 15/16/17's and they are called Star Corp

Starcorp Racing Wheels. Shadow Chrome, Light weight 5 spoke wheel avalable in Chrome, Silver and White.

15 x 6.5 Weight >5kg $170.00
16 x 7.0 Weight >6kg $200.00
17 x 7.0 Weight >7kg $220.00

Might be worth a look see

Erwino · Postby **Erwino** » Thu Feb 23, 2006 12:57 am

Craig wrote:Mania sell some light weight 15/16/17's and they are called Star Corp

Starcorp Racing Wheels. Shadow Chrome, Light weight 5 spoke wheel avalable in Chrome, Silver and White.

15 x 6.5 Weight >5kg $170.00
16 x 7.0 Weight >6kg $200.00
17 x 7.0 Weight >7kg $220.00

Might be worth a look see

they do look like a good price, plus nice and light for the 17"

but like it doesnt really show a very good picture, id love to see the 17" starcorp in like a chrome

Slugoid · Postby **Slugoid** » Thu Feb 23, 2006 1:28 am

Slightly off topic, but does anyone know who manufactures the stock rims?? I won't be suprised if it's made by some well known manufacturer. Often people buy aftermarket rims for the the looks, while it's actually more of a performance downgrade cos of the weight and build quality.

Anyway, what's your budget for the rims?? If you have the money, these will be perfect: http://www.gramlights.com/wheels/57pro/gallery.htm

Gram Light 57 Pro

Also, 16" will be the biggest I would go too if you value handling. I even reckon 16" are a tad to big for the NA's :oops:

, but that's just me.

Erwino · Postby **Erwino** » Thu Feb 23, 2006 1:48 am

Slugoid wrote:Slightly off topic, but does anyone know who manufactures the stock rims?? I won't be suprised if it's made by some well known manufacturer. Often people buy aftermarket rims for the the looks, while it's actually more of a performance downgrade cos of the weight and build quality.

Anyway, what's your budget for the rims?? If you have the money, these will be perfect: http://www.gramlights.com/wheels/57pro/gallery.htm

Gram Light 57 Pro

Also, 16" will be the biggest I would go too if you value handling. I even reckon 16" are a tad to big for the NA's , but that's just me.

price range is about $2000

something like this seems alright

http://www.tempetyres.com.au/products_c ... art_no=377

i wonder how much they weigh,

what do u guys think is the best looking wheels for a black NB

Matty · Postby **Matty** » Thu Feb 23, 2006 8:48 am

Slugoid wrote:Slightly off topic, but does anyone know who manufactures the stock rims?? I won't be suprised if it's made by some well known manufacturer.

Enkei I believe.