Fixx

Hi everyone!

I'm building a Miata based Locost, and there are some packaging advantages if I could swap sides on the rear hubs...

Is there any reason why i should'nt? Guess the brake attachment point will take the forces in the other direction, but is that a problem?

Thanks in advance for all input!

rdb138

iTrader: (1)

Hey Fixx,

Welcome to MiataTurbo. Unfortunately, you are going to get eaten alive here asking questions like above (and obviously have not done any research to help yourself and expect others to do that work for you. Very frowned upon by this community.)

I will help you with your research a little bit. The rear hubs (the part that spins) are universal and will fit either side, but I'm guessing you are asking about the rear uprights (aka rear knuckle). I would suggest you try putting one of the uprights / knuckles on the other side and then report back if that works for you or not and then ask any questions you may still have.

Good Luck on your project

Fixx

I'm really sorry if I stepped on someones toes here, certainly not my intention...

English is not my first language, which explain not fully grasping the nomenclature of the hubs/knuckle/uprights ...

Maybe that's why my google-fu did'nt work out, but believe me, I have searched myself almost silly trying to find some info... I can't find anything about it, and thought that a site dedicated to modding Miatas would be a good place to start...

​​​​​​I know that the hubs are interchangeable, and that the upright is mirrored, and has the top mount shifted to the front.. Using that space in front of the upright for a shock would be perfect... My guess, being a car builder more than an engineer, is that it does'nt really matter, but on the other hand, building the car and then snapping a upright brake mount under hard breaking would probably scrap everything since it would involve redoing 4 A-arms and most of the rear frame...

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rdb138

iTrader: (1)

I apologize, I wasn't trying to come off as a jerk. I doubt you will find anyone on here that has flipped the sides, so you are in uncharted territory. If you are going to build your own control arms and rear subframe / customize the Miata ones, you can probably make them work.

As far as the brakes. (I've never done this, nor am I an engineer, so take this advice for what it is...internet advice.) I would think they should work without an issue. (provided the caliper fits etc.)

My reasoning for this:

• The brakes convert the energy into heat, these bolts / bolt holes aren't taking the braking force. They are holding the caliper in place, not absorbing the braking force. (someone with a lot more knowledge than me probably can explain that better and will state that I'm semi wrong with this explanation, cause I'm sure some force is applied, but you get the idea.)
• The metal around both bolt holes are identical and you don't see any "support" on them that is built for a certain direction. Since they are circles, they should handle the load the same in either direction.
• Locking the brakes is about the most force you can put into the calipers. You can lock the brakes going in reverse on a Miata and you don't break off a caliper.

Some unsolicited advice. If you can reuse the Miata rear subframe and the control arms / suspension pickups, I would go that route. (Not sure of the width of your Locost). Sounds like a ton of work building a suspension vs bolting on a suspension that was built by a lot of professionals and works really well for being what it is.

Again, Good luck

Fixx

Thanks for the input! The forces on the brakes should invert when going in reverse, that's a useful thought... So they have to be designed for some load bearing even in that direction....

Using the entire rear subframe is not really an option, I'm aiming for a total weight of 5-600 kilos (1100-1300 lbs) and the original Miata stuff adds weight...
Besides, the donor car I got looked like this;


Subframes are hard to find over here in Sweden...

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codrus

I'm a software guy, not a mechanical engineer, but yeah, I don't expect it would be a problem.

The caliper bolts *are* taking the "braking force" -- they are loaded in shear due to the rotation of the rotor that they're grabbing. That said, people mount brake calipers on aluminum adapters all the time and it's hard to see how swapping the rotational direction on the rear uprights (which see far less load than the fronts) is going to make them weaker than aluminum.

I agree though that this is probably not the best forum for these sorts of questions, since most people here are using intact Miatas or possibly Exocets with subframe swaps. Have you looked at the locost USA forums ? The last time I checked there was a pretty healthy community of locost builders there, many of them using Miata donors and generally much more into basic chassis fabrication stuff than is the norm on miataturbo.

--Ian