Rear wheel arch width
 

I'm trying to sort out what wheels to purchase but I don't have my rear arches yet. :o
So what is the standard width from side of car to outer edge of arch for most suppliers (AGM, Equinox etc...).
With this in mind I should be able to determine what offset to order to fill out the rear arch if you see what I mean..:)
Also any suggestions what size wheel tyre combo to suit original MX5 speedo criteria.

The tyres for the speedo to read correct are 185 60 14's if this helps.

David

Pretty sure equinox ones are 11inch wide rear wings. Although Dave will make them any width you like.

Hi Johno,

For the wheel/tyre combo, if you change the wheel size of your donor, the tyre dimensions will change too (obviously :) ). You have "equivalences" of tyre sizes (ie if you want to fit 15'' wheel instead of the original 14''), but of course, they are not "exact". It is just a question of how many % difference with the circumference of the original wheels you are ready to accept. I think between 0 and 3%, it is acceptable for your speedo/mileage counter to be still "correct".

I used a French website to calculate mine, but I found this one in English. It is about Miata, so it is even better for you !

http://www.miata.net/garage/tirecalc.html

If, as Ben says, rear arches are 11'' wide, you can with no problem use a 7x15 wheels, same ET (offset) as the MX5 wheels in 14'', and a 195/50-15 tyre (-0.3% difference with the circumference of the 185/60-14)

Now, if you want your wheel to be as close to the edge of the arch as possible, you will have to recalculate the ET you need. But bare in mind that not all ET are available for a given size/centre bore (register)/PCD, so, I would stick to the MX5's ET.

Hope this will help :)

Equivalents
 

Check these out: http://www.midlandwheels.com/FitmentGuide.asp#maz

Thanks all for your advice...;)

Go for the 15 inch rims Johno, your car looks mint, it would be a real pitty not to fill those arches right out ! If you have a really understanding wife, get some magnesium alloys, they are light as a feather, keeping the weight right down just putting the idea out there:rolleyes:

Johno that is one seriously tidy build mate, can I just ask a quick question, what length have you made the arms for your headlight brackets and do you need to adjust them for the dia of the light unit itself.
My lights are 3.5" dia so would I need to compensate for the size but my plans are the same as yours to run the cables through the arms and keep it all minimal

Arfon

p.s sorry didn't want to distract from the original subject

Hi Arfon,:)
I think the measurement is 120mm from centre of light to edge of box, not 100% sure so will check tomorrow for you. I'm guessing this measurement is pretty standard and should be suitable for any size light.
The tube I used was 19mm same as top wishbones.

Hi Jason...:)
Gonna have a job getting that one passed the financial advisor....:eek:
Yeah I agree 15" would look good but might stick with 14" as I believe it's better to have a bit more tyre sidewall on these cars for handling.
I've been thinking about putting some 205's on the rear and 185's on the front what do you reckon?