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1/31/23 4:28 p.m.

Have spent some time lurking here admiring the quality of people's skills and their projects so here's a humble contribution from Ireland with my latest project:


My Dad was getting rid of this very ropey Smart Roadster with engine woes and generally in a sorry state, and in a weaker moment I decide to turn it in to a track day project. I'm aiming to make it as quick as I can by making it as light as I can, and as cheaply as I can. And I do mean cheaply. The engine isn't running and the gearboxes really don't suit track days so a bike engine it is. There's a bit of work needed before we get to that though.

Looking at it, it's a targa and the windscreen seems to add very little to torsional rigidity, so a very quick check on headroom:

and after some sparks and loud noises it becomes a speedster:


Excellent. No glass, bin the wipers and wiper motor and washer bottle, much lightness, and there's a touch of Lotus 3-Eleven/McLaren Elva vibes going on. If you're drunk and squint at it. I need to add strength in, so the doors are scrapped in favour of door bars, which the plastic door skin will bolt to. More triangulation will naturally be added here later, along with roll over protection of some description:


The servo is junked for a single master cylinder. Yes I know this isn't ideal but remember: light and cheap. I've never heard of these failing (had bother with one where the domed retaining washer was fitted backwards, that was no fun to diagnose) so I'm risking having only the one. Please don't judge me:



There's a bias valve to be fitted to the rear, installed under the bonnet in case anyone decides it'd be funny to move the lever when it's parked up:


The throttle pedal is fly by wire so no use really, so making a quick jig:


I made up a pedal using the existing bracket, and a relatively simple cable should do the trick from here.


Got a cheap and cheerful steering wheel with a removable boss, and machined the boss to fit over the standard splines. I plan on getting someone who can weld better than I can to weld this up for me! The plan is to slot the boss so that the weld isn't just circular around the column but travels up along the boss too:


I'm a little bit ahead of this with progress so will posts more updates shortly. 

Mr_Asa GRM+ Memberand UltimaDork
1/31/23 4:40 p.m.

Love it.  Always was intrigued by the shape of those little things.  Please, continue

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
1/31/23 4:57 p.m.

I am really interested to see where this goes. I've always liked the look of the Roadster, and to see one get turned into a mutant is going to be quite entertaining.

dculberson MegaDork
1/31/23 4:59 p.m.

I love it! I wish we'd gotten the roadsters here in the US.

Dusterbd13-michael MegaDork
1/31/23 5:00 p.m.

This is fun!

Shavarsh HalfDork
1/31/23 5:01 p.m.

So Rad!

Toyman! GRM+ Memberand MegaDork
1/31/23 7:02 p.m.

Having cut the windshield off a car before, I heartily approve of everything I've seen so far. 

Fun times!

1/31/23 7:08 p.m.

OK,,, we have established that you are not afraid of much and that you have a unique project in process. PLEASE do continue to update this thread.



John Welsh
John Welsh Mod Squad
1/31/23 7:12 p.m.
dculberson said:

I love it! I wish we'd gotten the roadsters here in the US.

Smart originally planned to bring the Roadster here. So much so that I remember sitting in one at the Detroit Auto Show, which I think is where MB launched the Smart brand to the US. 

I'm not talking that they had just one prototype on a platform, they had actual Roadsters there and you could sit in them. 

I was very disappointed they never offered the Roadster! 

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) GRM+ Memberand PowerDork
1/31/23 8:32 p.m.

Oh Snap!

wvumtnbkr GRM+ Memberand PowerDork
1/31/23 8:33 p.m.


XLR99 (Forum Supporter)
XLR99 (Forum Supporter) GRM+ Memberand Dork
1/31/23 8:34 p.m.

Wow, I never knew this was a thing!  Is it the 'standard' Smart platform with a different shell?  The wheelbase looks longer.


TurnerX19 UberDork
1/31/23 10:58 p.m.

There was a rental Smart Roadster in England when I was there in 2002. They wanted more deposit than I had for an 8 day jaunt. I was major disappointed in the normal rental I wound up with.

MyMiatas Reader
1/31/23 11:30 p.m.

Could we import one yet?? 

Floating Doc (Forum Supporter)
Floating Doc (Forum Supporter) GRM+ Memberand UltimaDork
2/1/23 1:05 a.m.

"Don't judge me."

Too late for that, there's already a bunch of us really excited to follow this. Welcome aboard!

AMiataCalledSteve Reader
2/1/23 9:07 a.m.

I love it when someone's first post is an amazing project. As a perpetual bike engine-swap dreamer, I'm definitely going to be following this one!

GameboyRMH GRM+ Memberand MegaDork
2/1/23 11:56 a.m.

Just make sure the handbrake's in good shape if you have a single-circuit brake hydraulic system. It's not a huge safety issue but it's a reduction in redundancy to be aware of and prepared for.

dculberson MegaDork
2/1/23 12:54 p.m.
MyMiatas said:

Could we import one yet?? 

Looks like a few more years yet. I believe the us exemption is still 25 years and the oldest smart roadster is from 2003 so 20-21 years at this point. Soon though. I bet the prices go up once they're import eligible. I saw some pretty cheap ones in the uk after a quick search. 

MotorsportsGordon Dork
2/1/23 1:13 p.m.

the brabus version had 100hp

NotSoSmart New Reader
2/2/23 9:18 a.m.

Thanks for the warm welcome and kind words everyone!

The more I work on the Smart the more impressed I am by it. And frustrated. It had so much potential and has so many nice touches but they really made it needlessly complicated, like they were trying to be too clever by half. If they had kept it simpler with more of an MX-5 ethos I think it's generally accepted that it could have been a huge success. Like did the tiny 3 cylinder engine really need 6 spark plugs when 3 of them are basically inaccessible? And of course there's the infamous gearbox:


A fully automated manual, with a three speed sequential cluster and with two final drives, giving six speeds. They really went to an awful lot of work to end up with a less than ideal solution. Anyway, there's a motorbike engine and gearbox going in this so I'm keeping the diff and driveshafts and the rest will end up where I'd suggest it should have been put originally (a skip). Firstly I removed the engine subframe:

Then made a jig to locate the diff, using cups under the driveshafts:

And, using an amount of mechanical butchering I'm not very proud of, removed the diff:

And putting it back in the car:

Now I wait to get the bike engine sorted and dropped in there, and figure out the best way to mount the diff.


Pushrod Reader
2/3/23 10:01 a.m.

In reply to NotSoSmart :

Which bike engine? Busa or ? :)

93EXCivic MegaDork
2/3/23 3:34 p.m.

Super cool project but I got to be honest that single master cylinder is a bit sketchy to me.

Dusterbd13-michael MegaDork
2/3/23 4:33 p.m.

In regards to the single master: im not worried on a track only car. Nascar ran singles into the 90s, dirt and other disciplines still do.

NotSoSmart New Reader
2/3/23 4:36 p.m.
Pushrod said:

In reply to NotSoSmart :

Which bike engine? Busa or ? :)

Maybe some day, but a Busa isn't in the budget unfortunately. Still, if I can prove the concept works then a Busa is the dream future scenario!

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
2/3/23 4:42 p.m.
Dusterbd13-michael said:

In regards to the single master: im not worried on a track only car. Nascar ran singles into the 90s, dirt and other disciplines still do.

Doesn't make the failure modes any better, though. Complete loss of braking when driving close to the limit is undesirable. Dual masters also give you more bias adjustment options.

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