The Micro Bike

[dimrub]

So I brought this little guy home yesterday:

So I was going to donate it to the bicycle museum (and I might still, eventually), but my eldest suddenly expressed interest. He wants something he can take on a train with him, and this should be perfect for that. I'm very happy about that, first because I have a bike to restore - for someone to ride, and second because I'm a bit nervous when he rides his gravel bike to the station and leaves it there - sometimes overnight.

So what do we have here? The front brake is missing altogether, so I'll need to source one, as well as a new set of grips. The SA hub is disconnected, but the indicator chain and the cable fitting are in place, so this should be a simple matter of replacing the cable, however the shifter seems broken, so I'll need a new one (these go for as little as 8 euros on Aliexpress). I might need to replace the chain, and I am not enthused about the pedals either (luckily, I have a spare set of folding pedals at home). I haven't checked the tires, but even if these are a bit tired , these are 20 inch and thus pretty cheap. The folding mechanism seems to be fine. The paintjob is fine, although I noticed that some of the yellow is mismatched - either it was repainted at some point in its life, or maybe it was badly painted to begin with. But anyway, no need to repaint, I think. All in all, a nice little project, with a clear goal in sight.

 

[Drago]

We demand a full write up with detailed pictures, diagrams, and all the fifty dirt you can dish.

 

[dimrub]

For reference: the "Micro"'s page on the site of the folding society, and a brief history of the brand on the FB page of the Micro club (yes, there's a club). There's this page too. There was also a thread on this forum about this bike.

Mine has a sticker of Cresswell cycling, which puts its manufacturing date probably somewhere between 1995 and 1997.

 

[FrankCrank]

Not heard of that bike before. The linked article shows a picture of a fracture next to the weld, next to the hinge. It describes it as a weld, as opposed to being brazed. To me it looks like a fillet braze, but the layer of paint hides a lot I guess. Could of course be a TIG weld? Just curious.

 

[dimrub]

Took a proper stock of things today.

The broken shifter, the missing grip and lever:

Some kind of loop on the steerer tube - perhaps the cables are supposed to go there, to avoid getting in the way of folding. My Brompton has a similar (albeit nicer looking) loop.

Some kind of hook on the down tube - I have no idea what is it for. Probably also plays a role in the folding process:

The decal on the drive side is heavily scratched. The chain wheel is bent, I'll try righting it with a brake disc tool:

Another loop - here the cables part ways: the brake goes up, the gear is supposed to terminate at the next loop, currently vacant.

A nifty device for keeping the cable at a proper angle:

The rear mudguard is broken, while the front one is missing:

Some kind of rear light hook, and a very old-fashioned cable cap:

Some kind of strange devices on the seat post - I don't think I need them for anything. I'll also be replacing the seat post clamp, to make folding easier:

The bike was sitting on deflated tires for too long, so tires will have to be replaced:

Luckily, these are 16", and I have a set that used to be on the Brompton that I can use.

Made in 1996:

 

[dimrub]

Ok, by careful examination of the photos in the other thread, I can see that the loop on the steerer tube is not for the cables, but rather used to catch the steerer against the down tube during folding. And the white thingy is the catch (and it's broken). So the shopping list seems to consist of the following:

- An SA shifter
- A set of grips
- A front caliper (but maybe MBK's will fit here - according to the photos, an up pull was used originally, and it's a long reach, just like MBK's)
- A chain
- A set of mudguards
- A seatpost clamp

Things I'm going to reuse out of existing stock:
- Pedals
- Tires & tubes
- If I can't right the chainring, maybe reuse the crankset I got for Brompton which was not a good fit there.

The broken hook seems unlikely to be available anywhere, so I'm thinking about 3D-printing a replacement. I might need to figure out how to connect the cable to the indicator chain - on the Brompton there's a special bolt with a hole for the cable there, but maybe a regular bolt will do.

 

[dimrub]

Took the Micro apart today. Some more issues I haven't noticed before:

- The BB was stuck - I couldn't see that before because of the bent chainring. Once I took it apart, I realized why. It was full of dirt. I don't know what could cause such a calamity - it's as if it was greased generously, then all of the grease converted into completely dry gunk. Also, the spindle is rusty.
- The steering tube was rotating freely. Once I folded the steering tube, I realized why: the stem is missing, bolt and all. I'm not sure how to get a replacement - I'll try to measure things to the best of my ability, then order one for a generic folding bicycle with same measurements - hope that works.
- The indicator chain is stuck. This is a delicate one, hope I'll be able to unstuck it in order to regrease it.
- Everything is quite dirty, of course - that goes without saying.

P.S. That stem is weird. It's supposedly a quill stem, but the bottom part , where the moving part connects, is not angled, but rather straight. So the moving part of the stem, when screwed in, is not pushing against the steering tube, but rather retracts into the fixed part of the stem, pushing it outwards, and it in turn pushes against the inside of the steering tube. Kind of like this one, I guess. I'm not sure I can get just the missing parts, which are the bolt and the inner, moving part. I mean, I can get a bolt, but how do I replace that moving part? A bit of a mistery, that.

 

[FrankCrank]

Re the stem, my Puch Promenade has something similar, ie an alternative to the wedge system. The wedge is the better system in my opinion.
You could quite easily convert yours to a wedge type, if you prefer that option.

 

[dimrub]

Re the stem, my Puch Promenade has something similar, ie an alternative to the wedge system. The wedge is the better system in my opinion.
You could quite easily convert yours to a wedge type, if you prefer that option.

Oh, you mean cut the bottom of the stem diagonally? I guess I can try that, yes. Did you do it yourself?

I have the MBK's stem that I can get the wedge from. Sounds like an adventure!

 

[Drago]

Photograph those decals and get Gil on Retrokbikes to make you some new ones, get that frame powder coated. It'll never be worth much hut it's a wonderful curio and deserves to be preserved.

 

[dimrub]

So I was scouring the internet looking for a cone expander replacement, and on a whim I took another look into the steerer tube. There was something there. I poked with a screwdriver, and out came the cone! No bolt, of course, but I just happened to have a fitting bolt at home. So problem solved.

But now there's another one. As I was cleaning the rear wheel, the indicator chain just snapped, right at the entrance into the axle. Luckily, I was able to extract the remainder, but I'm now an indicator chain short:

This one is not as hard to source as that cone (though not cheap, for what it is - about $13 including shipping).

Photograph those decals and get Gil on Retrokbikes to make you some new ones, get that frame powder coated. It'll never be worth much hut it's a wonderful curio and deserves to be preserved.

I think I can make a new set of decals on my own - it's just 2 words, the only trick to it is finding the correct font. I'm definitely not going to touch the paint - it's good enough as it is, and with a bit of polish it now looks even better. I wouldn't want to risk making it look better than when it was first manufactured!

 

[FrankCrank]

Oh, you mean cut the bottom of the stem diagonally? I guess I can try that, yes. Did you do it yourself?

I have the MBK's stem that I can get the wedge from. Sounds like an adventure!

Looks like you've got it solved now, well done. Have done that bodge as I described, just got to make sure the wedge fits, as they vary a little in size. Now I've seen the pic, doubt the bodge would work for you, looks like not much tube to play with.
Great project - keep the updates, and pics, coming

 

[dimrub]

The headset seemed to be ok, but I took it apart and regreased just the same. Did the BB too, and reattached the stem - it worked perfectly. Next up is straightening the chainring.

Also, my eldest, for whom the bike is earmarked, needs to choose a seat. There's the lousy foam saddle that came with the bike, there's a few saddles I took off various bikes, and there's the Chinese knock-off of Brooks that I nick-named Brooks Li.

 

[Javelin301]

The broken hook seems unlikely to be available anywhere, so I'm thinking about 3D-printing a replacement. I might need to figure out how to connect the cable to the indicator chain - on the Brompton there's a special bolt with a hole for the cable there, but maybe a regular bolt will do.

I had a Micro for a few years. That hook is just a standard plastic plumbers pipe clamp. They don't last long but they're cheap - think I had to buy a bag of 50 from Screwfix. They are great little bikes.

 

[dimrub]

I had a Micro for a few years. That hook is just a standard plastic plumbers pipe clamp. They don't last long but they're cheap - think I had to buy a bag of 50 from Screwfix. They are great little bikes.

Ah thanks, I thought of visiting a hardware store for the stem cone, but not for the hook!