Possible Miata 5 Lug Conversion?

[schwac2]

After searching for months for a possible way to convert the miata hubs to 5 lug, i think i have a way to do it, relatively easily:
1. For rear hubs, swap the miata hubs with the front driven hubs from an 05 beetle, jetta, golf, etc. or any year model that uses the same hub. Each model uses the same 5x100 hub. Both the miata and the VWs use a rear wheel bearing that is 40mmx70mmx40mm. I think the hubs from an Audi TT also work. These hubs should be a direct fit, identical swap. The dimensions provided on RockAuto for the two sets of hubs match.
2. For the front hubs, it may be possible to use the rear, non-driven hubs from the VWs as well, though I'm not sure for certain - some of the specs are different, such as the flange offset. This would change the geometry somewhat, affecting the scrub radius, if the stock miata suspension layout is used. But, it seems that the spindle fitment should work - i have not bought one to try it out, though so this is just speculation. The other solution i have read that is successful is purchasing rear hubs from a '93 Probe and machining a spacer to sit in between the larger ID hub bearing and the smaller OD spindle. THe Probe has a 5x114.3 pattern though, not 5x100 like the VWs.

Please note that this gives a 5x100 pattern, not 5x114.3, which seem to be the more desirable pattern.

Even after finally finding this solution, i think i will be sticking with the stock hubs, as i have already replace the front hubs with new stock ones and don't really want to spend any more money to swap to 5x100 (i found 4x100 wheels i like so there isn't much of a driver any more). Thought i'd share.

Does anyone have the rear, non-driven hubs from a later VW that they could report on?

[Glen]

Do you have any evidence that the axle splines are the same?

Have you considered keeping one of the studs and drilling 4 new holes to make a 5 bolt pattern? I think that generally works out for swtiching from 4 to 5 or 5 to 4 if you keep the same bolt circle diameter.

[Driven5]

Please note that this gives a 5x100 pattern, not 5x114.3, which seem to be the more desirable pattern.

Actually 5x100 has become a much more common bolt pattern over the years, my guess is that this is due in no small part to the large WRX modification market. So it's really not that bad of an option. However actual bolt pattern "desirability" is going to depend significantly on what size wheels you plan to run. Availability of 15" wheels is much better for the 4-bolt patterns, than it is for the 5-bolt patterns. But as your needs require larger diameters and wider widths, so too does the "most common" bolt pattern grow.

[schwac2]

I have no idea about the axles - for my project i never considered that, as i assumed that i would need custom axles (drivetrain will not be Miata, and track width is most likely going to be different).

Some people have recommended redrilling the hubs, though I'm not too keen on that approach. Given that our cars are ~1/2 the weight of the original donors, it's probably not a problem, but I don't want to sacrifice safety (hub failing) for vanity (good looking wheels). It may be overly conservative, but it seems that the potential is there, however small.

FWIW, i have been looking at larger wheels, 16" and 17", which commonly are less available in 4 lug.

[Thinkkker]

I don't think there is enough room in the miata hub to redrill at a 5x4-1/2.

I have not measured the rear in the shop, but all my info is saying that....

[schwac2]

UPDATE: I take back what I said about not trying this conversion - I ordered the rear driven hubs from an 05 Jetta and got them in today. They are similar to the miata hubs. Differences:

1. They are ~7mm shorter from the back of the flange to the back end of the hub (the end that goes into the wheel bearing). The miata is 50mm while the Jetta's is 43mm.

2. The brake pilot diameter on the Jetta is ~65mm, while the miata is 55mm.

3. The wheel pilot diameter on the Jetta is 57.1mm, while the miata is 54.1mm.

I don't have my suspension figured out yet, so it's not a problem for me. The only thing this will affect is the space between the back of the flange and the lip of the upright, but since the Jetta uses hub bolts that thread into the hub there are no lug heads on the back of the flange to worry about.

I had a few old miata wheel bearings hanging around and tested the Jetta hub's OD and they fit perfectly into the bearings. The 7mm difference in length is the only thing to worry about if you have already done the suspension design.

To answer a previous question, the Jetta hubs have 36 splines.

If I decide to go down this road and order the Jetta's rear hubs (non-driven) i'll update with how that goes.

[schwac2]

Another Update:

Front Hubs:
I purchased 2 front hubs from a '95 Plymoth Neon and they were a direct fit onto the miata front spindle. The only thing needed to make these work is a spacer that would sit beneath the axle nut, as the wheel bearing on the inside of the front hub isn't as thick as the miata's. I think the spacer needed to be 6-7mm or so. The flange offset is also slightly different, changing the track width.

With this setup, all of the wheels are a 5x100 pattern.

After doing all of this I am happy to report that I won't be using any of it, and will be going back to the miata hubs - at the end of the day, using stock miata hubs, rotors, and calipers is cheaper, lighter, and less complicated than sourcing lightweight rotors and fabbing caliper brackets to accomodate the new rotors, though rotors with larger diameters can be found on the 220hp Audi TTs, making for a cheap BBK. Probably shouldn't have popped off the ABS rings on all 4 hubs that i'm not using...

[Blackbird]

I guess I have to ask, why would you convert miata hubs to 5 lug at all?

Moti

[schwac2]

It's a topic that people are interested in over on the Miata forums because it opens up a lot of larger wheel possibilities. There are plenty of arguments for and against doing it, but I think this was just information on how to do it.

[nufun]

2 things

1. Going to 5 lug would push you to larger wheels. Yes you can get a wider variety of wheels, but in most cases that would be 16 and above. Something most seven's really do not work well with.

2. Definitely do not go to the 4x114, I did some research a few months ago when I was planning on running the sierra suspension and I found it next to impossible to find anything I liked, or in the weight that was reasonable.

I would stick with the 4x100, I think you have more options.