re[2]: mags tyres, the whole shabang

[Mathew]

I'm no expert, but you'd think Mazdaspeed would be. I was looking through one of their catalogues a while back and noted that they sell 15" wheels for the mx5 in a 35mm offset. I also seem to remember reading somewhere that as the width of the tyre/wheel increases you should decrease the offset a bit.

Matt
91' with 17" Kosei Seneka's (35mm offset) and very happy with them.

[shaznandy lockyer]

Yes, Mathew
My ROH 15''ers feature a 35mm offset, too...Interesting, too that some very well set-up cars are running 14'' or 15'' wheels only and that MAZDASPEED offer that size and some official literature makes mention of this size as an upgrade but generally emphasize the EXHAUSTIVE testing Mazda conducted before fitting the MKI with 185/60R14's...many overseas racers in classes that allow some modifications run these sizes also...
Mathew <matt@deepvideo.com> wrote: I'm no expert, but you'd think Mazdaspeed would be. I was looking through one of their catalogues a while back and noted that they sell 15" wheels for the mx5 in a 35mm offset. I also seem to remember reading somewhere that as the width of the tyre/wheel increases you should decrease the offset a bit.

Matt
91' with 17" Kosei Seneka's (35mm offset) and very happy with them.

[Scott]

ooh Matt, got some pics of yer mags? It's much easier letting someone
else do all the hard work hehe

[zorruno]

I run 40mm offset 16" and like it for everyday use. Ride is a bit on the
harsh side though with uneven surfaces. Yes - I have tried other setups,
but not less than 40 offset - (See archives)

I'm no expert, but you'd think Mazdaspeed would be. I was looking through

one of their catalogues a while back and noted that they sell 15" wheels for
the mx5 in a 35mm offset. I also seem to remember reading somewhere that as
the width of the tyre/wheel increases you should decrease the offset a bit.
[...]

[Matt Gunn]

Hi there

We run 14" polished factory alloys. The ride is bloody hard.

who cares

cheers

MADMXV

[Gary Morrison]

Hi Matt,

I'm just passing on what I have learnt through listening to those who know,
and having made all the wrong choices myself in the past. I had heavy 15"
35mm offset wheels and now have lightweight 45mm offset 15" wheels and the
difference is substantial.

Quoting from "The Mazda Miata Performance Handbook"

Page 23

Offset

The most difficult dimension in the Miata's wheel-design package is the
offset. Mazda created the Miata wheels with a 45-millimeter offset to be
able to make room for the brake calipers and to fit into Mazda's family
wheel system. Unfortunately, 45 millimeters isn't a standard number in the
industry. Most aftermarket wheels have 35 to 37 millimeter offset, and
therefore don't match the Miata system. These wheels will physically bolt to
the car and even look correct, and to the casual driver, no untoward
behaviour will result. But to the critical enthusiast, the 10 millimeter
difference will create unacceptable handling quirks. The salesman at the
tire dealer might gloss over this point, but when your car bushings are shot
and you can't stand the way your car darts around since you got those hot
wheels, don't blame Mazda - blame yourself for using the wrong wheels.

And page 25 under an illustration of the suspension and wheel

When you use a wheel with an offset other than 45 millimeters, some scrub
radius is created, which acts as a lever arm. When the brakes are applied,
the contact patch pushes on this level arm and tries to self steer the car.


Also if you go to the url referenced by Jeff
http://www.good-win-racing.com/goodwinracing_005.htm you can see that the
preference is for close to factory spec. I think the 15" wheels on the newer
cars is a 40mm one, but this make also be part of the slightly altered
suspension geometry that I understand the newer car has.

Gary

[zorruno]

have you considered putting tyres on them

[...]