17x7 on an NB Mx5?

[Rachelsmx]

Hi guys,

I have a 2001 NB8B with HSD coilovers. I have them almost as high as stock, because they came with the car but it was really impractical for me so I raised it fairly high.

I am looking to buy some nice black rims, however I am on a budget. I'm looking to go for a nice 2nd hand set of decent rims with tyres. My stock wheels as most would know are 16" x 7.5". I have found some nice looking, good priced advanti rims that are 17" x 7".

My actual question: Is the width going to be a major difference, particularly as in this case I am going for a 17"?

I did read other threads, but have not found one specific to my question of width with 17".

Thanks

EDIT: Oh! I almost forgot, the reason I don't mind going up to a 17" is because it'll get me a tad high off the ground so that I can lower the coilovers that tad, that way it doesn't look so stock. I'm not much of a hoon and I don't take it to the track ;) I'd just like it to look to my taste.

[kazama]

theyre narrower than the 16s, so it shouldnt be a problem depending on offset

[Charlie Brown]

The standard rims are 16x6.5 not 7.5.
There are two very important things to keep in mind when getting new rims for you MX-5.
First up is weight. You need to keep it under 8kg per rim.
Next is off-set. Here you should try to match the standard figure as closely as possible. I'm not exactly sure what it is on the NB but say it's 50mm. You can go down to 45mm without much problem. Stay away from lower offsets.

[mx5002]

I thought stock nb8b wheels are 6.5 +40 offset

Either way 17 x 7 (or 8") wide would be fine even up to a +30ish offset

Most ppl stay away from the larger wheels (diameter) on our cars in the search of comfort.. And moar low

I run 15x8 +25 and it fills out my gaurds nicely without rolling gaurds etc

[pezchops]

you need to keep the rolling diameter stock, so any size rim (14,15,16,17,or 18) you still need the correct tyre fitted to give the same outside diameter.
you will not gain height unless you fit the wrong diameter tyre, then your speedo will read incorrectly.

[Lokiel]

The SE (called the "MSM" in the US) came with 17x7 rims - here's a whole thread of guys that upgraded from them: http://www.mazda-speed.com/forum2/index.php/topic,16546.0.html

Please read it.

In a nutshell why 17" rims are bad on an NA/NB:
1. They're heavy - this will impact the cars handling (your wheels are basically flywheels/gyroscopes; heavier wheels make turning harder).
2. They're heavy - this will reduce your acceleration (see #1; definitely not good in a low-powered car).
3. They're heavy - this will increase the distance required to brake (see #1), and require more effort (pads will wear quicker too).
4. Tyre choice is much smaller than 15" tyres and they're more expensive.
5. 17" rims mean you'll be running a low profile tyre so you'll feel every bump/pothole (ie. the ride turns to crap).
6. 17" rims mean you'll have little sidewall flex which is not a good thing with regard to handling/ride.
7. 17" rims are more prone to damage since there's little sidewall to absorb pothole impacts.

Why 17" rims are good on an NA/NB:
1. Some people think they look good (I'm not in that camp).

[Rachelsmx]

Thanks guys,
and you're right the stocks are 6.5" my bad.
the ride is already rubbish, I hate the coilovers so I'm not too concerned about that as I just put up with it (it only bothers me when I drive my mum around as I can see she's not keen on the bumps - that's sportscars and young people for you)

The offset of the Advantis I'm looking at is +40, which is the same as stock I believe.
I don't know the weight of them.

everyone will have different opinions on style etc, I'd never make everyone happy -
My main concern is safety, I wouldn't want to slip out even with the best of tyres.

thanks for such great responses!

[Mr Morlock]

its not actually what sportscars are. The MX5 is actually a surprisingly comfortable car light years in front of older style sportscars- I guess I am showing a bias in taking note of what Lokiel has posted.

[Rachelsmx]

its not actually what sportscars are. The MX5 is actually a surprisingly comfortable car light years in front of older style sportscars- I guess I am showing a bias in taking note of what Lokiel has posted.

I said 'young people' and sportscars - as in poor people attempting sportscars - it was a joke ;) probably more humorous among a group of uni students such as myself and fellow students with nice cars

[bruce]

If the ride is already rubbish, it will get worse with 17s.

[Lokiel]

Have you tried softening your HSD's dampers?

All it takes it a twist of the knobs at the top of the shocks - I'm betting the PO had them cranked up to Full-Hard in the belief that Full-Hard is "the bestest" for handling.

[Rachelsmx]

Have you tried softening your HSD's dampers?

All it takes it a twist of the knobs at the top of the shocks - I'm betting the PO had them cranked up to Full-Hard in the belief that Full-Hard is "the bestest" for handling.

Yeah, I've tried all different things, its either too rough or too bouncy haha. I've got it at a decent dampening now, I'm not really complaining anymore

[Lokiel]

Have you tried softening your HSD's dampers?

All it takes it a twist of the knobs at the top of the shocks - I'm betting the PO had them cranked up to Full-Hard in the belief that Full-Hard is "the bestest" for handling.

Yeah, I've tried all different things, its either too rough or too bouncy haha. I've got it at a decent dampening now, I'm not really complaining anymore

FYI: (from dictionary.com)

DAMPING
damp⋅ing
  /ˈdæmpɪŋ/ Show Spelled Pronunciation [dam-ping] Show IPA
–noun Physics.
1. a decreasing of the amplitude of an electrical or mechanical wave.
2. an energy-absorbing mechanism or resistance circuit causing this decrease.
3. a reduction in the amplitude of an oscillation or vibration as a result of energy being dissipated as heat.

VS.

DAMPENING
damp·en (dām'pən) Pronunciation Key
v. damp·ened, damp·en·ing, damp·ens

v. tr.
1. To make damp.
2. To deaden, restrain, or depress: "trade moves . . . aimed at dampening protectionist pressures in Congress" (Christian Science Monitor).
3. To soundproof.

v. intr.
To become damp.
damp'en·er n.


Sorry, my anal nature just bust out onto the internet since that's one of my "pet peeves" (not as irritating as "loosing" vs "losing" though).

[Rachelsmx]

Sorry.

[Magpie]

It sounds like a spring issue, twisting knobs will not fix a spring frequency issue. Do you know the spring rates fitted?

The higher the frequency, the stiffer the ride.
0.5 - 1.5 Hz for passenger cars
1.5 - 2.0 Hz for sedan racecars and moderate downforce formula cars
3.0 - 5.0+ Hz for high downforce racecars

Lower frequencies produce a softer suspension with more mechanical grip, however the response will be slower in transient. Higher
frequencies create less suspension travel for a given track, allowing lower ride heights, and in turn, lowering the center of gravity and hence a siffer ride.