MBB on the road

 

Hi 

About six months ago, I posted here about a new bike design, and at that stage had made a fairly wonky prototype. Now, after quite a bit of work I've got a nice working machine on the road, and have even painted it a colour that's not black!  

Here in Melbourne we had a few very hot days with bushfires last week, and I used that time to do the final disassembly, paint prepping, painting, frame mods and assembly, with the bike inside in the airconditioning for some of it. There were a few total fire ban days, and that included the days after the scorching hot days when I was rounding off the front part of the frame. The total fire bans include not using power tools such as grinders outside,  and I was quite pleased to be able to finish off the frame nicely using just a hacksaw and a file.

All the cables are tidy now, and I've put custom 3d printed plugs in 2 places at the front, complete with head tube badge symbol "M" for modular bikes.

As per the last test ride, I went to Piedemontes supermarket in North Fitzroy, however now this trip has become something of a pleasurable necessity, as our local neighbourhood (East Clifton Hill) small supermarket "Flower of Sorrento" has shut down permanently. 

Anyway, the trip went well, and I ventured up the stairs to the "Variety" section of the supermarket where I was delighted to find a small caf selling an egg and bacon muffin and a hot chocolate for $10.00. Normally you can't get a poke in the eye with a burnt stick for that amount in Melbourne cafs!

The bike carried my shopping easily. I was going to call it X15 Mk2 as discussed here , but now I think its new standard destination has named it: The "Piedemonte Special".

Convertible mbb to fbb part2

After a quick trip around the block - 

 

it all went ok but - 

the chain is hitting on the V-brake boss. A bit of sawing and angle grinding should fix this!

Bosses for V-brakes added.

Split in boom.

Adding 2 bracing tubes. There is a stick of aluminium shoved over the tyre as a heat shield.

After tacking support tubes into place.

Update 1/1/2026

I rode it around the block and it goes well! There is a small issue with the chain rubbing on a brake boss which a bit of sawing and angle grinding will fix but otherwise good!  In terms of a name and colour scheme for the front bit, I think it has to be X15 mkII. Some of the boom clamp mechanism is reminiscent of this much earlier bike ,  which was named after the orange paint colour used at my old work at CMG electric motors. As well, there's bits of orange paint still left on the steerer frame from the original donor bike which is begging to be restored, and the colour is a nod to my last moving bottom bracket bikes which were orange Cruzbike Quests.

Hi

Today I spent some time on this bike, and had done a bit of work previously, and now I am within striking distance of finishing the mbb part of this bike. The bottom bracket boom is now splittable and is braced from below. When I tacked up the bottom bracket bracing I was careful not to let the brazing interfere too much with the bottom bracket threads. 

With a bit of luck I will test ride tomorrow! Happy New Year!

Brake removed to show v-brake boss detail

More detail: 4 holes in steel strip altogether, 2 on the edge simlify bending, 1 holds the spring retainer pin and the large one is tapped M10 for a standard v-brake frame boss.

Convertible mbb to fbb

 

Current moving bottom bracket bike with proposed fixed bottom bracket piece clamped alongside.

Bottom bracket position will be traced onto the new frame piece.

Overall view

Not sure if its discernible here, but the bottom bracket looks slightly askew.

Current bike with a bottom bracket / pedal mount that moves when the steering moves - moving bottom bracket front wheel drive.

New proposed version where the chain twists during steering, and the bottom bracket is secured to the main frame, so stays fixed during steering - fixed bottom bracket front wheel drive.

 

 

Hi

After a while spent riding a new front wheel drive moving bottom bracket bike, I have decided to make it convertible between fixed bottom bracket and moving bottom bracket. There are a few reasons for this.  One is that the current bottom bracket seems to be attached crooked, and one style of fix for this could include making it removable. The second is that I can, and the third is that a comparison of moving and fixed bottom bracket bikes should be interesting.

 

To take these photos I stripped out the bike's pedals and pedal bearings. The next job is slightly off topic, there is currently only one brake and I plan to fit another - a set of v-brakes at the back of the fork. Will report more soon!

 

Ultima Yamaguchi Mixte

 

Hi

A few weeks ago, the bike shed where I volunteer was having a cleanout, and we removed many bikes from the shed. Some were to go to scrap, others to be fixed. Behind a lot of bikes was a mixte frame - I quite like these bikes and have documented fixing  them here and here. 

The frame had most of a headset but no fork, and the centre pull brake on the frame ended up not fitting on my rebuild with 700c wheels.  I grabbed the frame during the cleanout and have been fixing it off and on ever since. I managed to find one other Yamaguchi frame Mixte on the internet, here is the link. However the brand name Ultima seems to have disappeared without a trace. There is a Figtree Cycles sticker on the bike, and I found that Figtree is a suburb of Woollongong  - a large town on the New South Wales south coast.

To get a working fork, I needed to put in extra thread onto the silver fork I had - this was a first use for an oversize tap I bought a while ago and am happy with results. Another custom job was making a rack stay.

Looking on the internet, I found that Yamaguchi bikes are also branded "Record" in Australia.  I'm happy with the results here. The bike will probably be sold for Wecycle, and there's still a bit to do. This was fixing, not restoring - it's to be used and there's been no slavish devotion to using original parts. Hopefully soon it will be back on the road and in use soon. 

Regards

 

Steve Nurse 

CLWBFWD PART 3

Tubemitre profile stuck to steel tube.

 

Tubemitre marked up on fork extension piece. The black line is above the blue lines where I cut with a hacksaw.

 

 

Very temporary arrangement with the bottom bracket tube taped to the fork extension

2 views of the...

clamping before brazing which tries to get everything square.

Brazing done. The donor bikes mudguards can be seen in the background.

Frame without seat.

The first time I went further than round the block. When the power was out one morning I went to a local caf and also to the nearby church op shop.

The bike in current form. I'm currently overhauling the tailbox.

Hi

After some work, my compact longwheelbase, moving bottom bracket front wheel drive bike is now on the road. It works way better than the proof of concept bike I had several months ago, and I am (gingerly) using the bike for regular commuting and shopping and junk hauling tasks. Post test rides, I have changed the brake position and fitted a 180mm disc brake rotor.

 There's still a way to go with this. The fork is quite heavy, the bottom bracket looks slightly out of alignment and there's the occasional clunking, but overall I'm pleased. Will report more soon and get some better photos.

 

 

CLWBFWD part 2

 

Quite a short post compared to my last effort!  The bike discussed in my last post has been progressing albeit slowly. For a new version of the bike which should look less contraptiony, I ordered in some new parts. They arrived while I was away for a few weeks, and I have been adapting the frame I have already to take those parts. The parts are a fatbike  / ebike / aheadset fork and an aheadset. 

 The aheadset was a pleasant surprise, and the first headset with sealed bearings I've seen. Sealed bearings are in bottom brackets, front and back wheels, and derailleur pulleys. Mainly they help exclude muck, but in this case they would also help in a travel bike where headset disassembly is part of the packing down for transport.

I didn't have the right sized holesaw for the job so used one that was undersized and filed away till the aheadset bearing housings were a snug fit. For marking out the target circle and filing I used a 3d printed guide.

 Very happy with the result and I'm keen to get going again with building CLWBFWD MKII.

 Update August 29

 I've put some work in over the last few days and my new bike is coming along well. Today I roughed out 2 parts that will end up as the steerer and bottom bracket support, and updated my drawing (its still a bit rough!) of the completed bike. I had to saw away part of the bottom bracket shell to get it to come out, and some unwanted donor frame bits are on their way to recycling. pics below.