Bianchi Theridion

Now here’s an odd looking mountain bike. 


The jaunty angle of the saddle and the plastic bag make this look like a tired commuter, but given it’s pedigree, original components and bizarre frame design, surely this is a diamond in the rough?

What do you think?

BMC Fourstroke FS04 (update 3)

You may have been wondering what happened to the BMC mountain bike restoration project I started a while back.

Like many projects it got to the “nearly finished” stage and sat there for a good six months causing a nuisance to the family. 

Good news that it’s now moved on to the “basically finished” stage…

It was cleaner, but is now dusty from riding. So apologies for the photos, but it’s great that it’s rideable!


On an earlier test ride, I noticed the left pedal crank creaked on the downstroke, which it didn’t on my first test. This suggested a worsening issue, so I inspected further.

Anything other than a smooth bottom bracket/crank is bad news. A lot of torque goes through there, plenty to cause damage pretty quickly if not addressed. 

I found an allen key large enough to remove the pedal cranks, and discovered a Shimano Octalink bottom bracket. This is the first Octalink system I have owned, with all my older bikes having square taper BBs. 

I also found the non-drive side (left) mating splines to be slightly chewed at the end. Apparently this is common with Octalink systems, and happens when the crank arm isn’t perfectly aligned, prior to screwing the crank arm bolt back on. So, as I had never removed it, this damage was done by the previous owner, though it seems odd it didn’t creak on the first test ride. 

In short, the crank arm is toast and needs replacing. The BB itself is in good condition and runs smoothly, so is perfectly reusable, but as Octalink is no longer common, finding replacement crank arms was an issue. Basically I could only find a new Alivio set which would be fine, but for the fact it wouldn’t add to the overall look of the bike. 

After a little cogitation, it dawned on me an alternative might be right under my nose…

Some time ago I rescued a binned Steppenwolf hardtail MTB frame with some components still attached, including XT cranks and a more modern external bearing BB. Why not see if it’s the same width as the octalink BB?

Lo and behold it was, so I would theoretically be able to replace a Deore LX crankset and Octalink BB with an XT crankset and modern external BB, at no cost. Not bad at all and 100% eco-friendly.

One problem. Don’t have the right tools! 

As systems evolved, so the tools needed to work on them change. Though this a consequence of welcome technological innovation, it poses something of a challenge for the home mechanic.

A regular crank extractor tool doesn’t work with an Octalink BB. To remove a BB on a vintage bike you need a hook spanner, an Octalink BB needs a BB removal nut thingy (like for a cassette but bigger), and an external BB uses another type of large spanner with slotted splines. Consequently, you often need different tools to work on various bikes. 

The bike shops near me aren’t really set up for the home mechanic, so buying tools is interesting and expensive. Apparently, in Switzerland, folks like to get other people’s hands grimy instead of their own (which probably makes sense).

As I quite enjoy grimy hands and torn knuckles I set about looking for tools and stumbled across a sale on Chain Reaction for an 18 piece toolset, for 50CHF delivered, including some tools I had already, everything I needed for this job plus a couple of extras. Pretty good deal, and arrived within a week. 

Once the package hit the doormat, like a child on Christmas morning I ripped it open and within 20mins had replaced and upgraded BB and crankset and chainrings to higher spec parts. Great!

The toolset is made by X-Tools, and though I was hesitant about quality given the price, I am quite pleased. 

The “new” drive train all works perfectly and it’s always most satisfying to complete an long term unfinished job.


So the moral of the story is, if you can salvage used parts, do so. You never know when you might need them and they’ve often got lots of life left.

Secondly, always invest in (quality) tools. Even if technology changes, and you only use them a few times, they pay for themselves quicker than you think.

Also, that which is new today will be vintage tomorrow, so there will always be more bikes to work on! 

Velobrico workshop: SRAM X4 rear derailleur 

A while back I picked up a trashed Specialized Hotrock kids bike. The frame looked sound but everything else was pretty far gone. 

This bike would need far more workshop time than it’s replacement value, so it’s owners rightly binned it and moved on. But it’s a decent size for my son’s next bike, giving me enough time to fix it up before he can ride it.

Among numerous other issues, the derailleur hanger was bent, chain broken and derailleur was in a sorry looking state. 


Looking past first appearances, a number of components, including the derailleur, looked salvageable. 

I straightened the derailleur hanger with a pipe wrench plier and then set to the derailleur itself. 

It’s pretty straightforward to service a derailleur, remove, clean, degrease and regrease jockey wheels then reinstall. But it’s a bit of a dirty job, so rarely gets to the top of the DIY service list. 


Like with most things, putting it back together again is considerably less intuitive than taking it apart!

After getting it completely wrong, I removed the jockey wheels again and correctly rerouted the chain, using the smallest cog and chainring to give enough slack to work with. 


Some adjustment to the derailleur cable and a liberal dose of WD-40 on a rusty chain and cassette later, and we’re good to go!

Total bench time, maybe 40mins on a rainy Sunday afternoon?

Oh yeah

Finally the wait is over. I bought my first Italian bike. 

And what a bike! 

Can’t wait to pick it up…

Velobrico Tinkering: Dynamo lights

Though I have absolutely no experience with dynamos, nor any real idea how they work, last Sunday I decided to tackle the non-functioning rear light from the Tigra ladies’ bike.

This bike has a dynamo installed, even though it is not such an old machine. I was recently told that in Germany it is illegal to ride a bike with battery powered lights. I’m not sure if that is true, (German cycling laws here…) as it does sound pretty nonsensical, though I’m pretty certain you are allowed to ride in Switzerland with whatever lights you want.

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Once I figured out how to engage the dynamo so it would work from tyre rotation (this seriously took me a few days of prodding and pulling to figure out), the front light functioned fine but the rear refused to shine.

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First, I removed the plastic housing and checked the bulb. Filament looked ok. Checked continuity with the multi-meter, all good. Screwed it back in. Crossed my fingers. Nothing.

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Then I had a look at the wiring. The dynamo has two wires coming out of it, one for the front light, another for the rear. Not sure how this can make a complete circuit, but I guess that’s not necessary for DC power. The bulb socket seems to be connected to the mudguard itself, so presumably being grounded is sufficient for a DC circuit. My lack of electrical knowledge is by now apparent.

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The wire hanging out of the bottom of the dynamo seemed loosely connected, but I noticed a spring-loaded connector in the bottom which holds it in place just fine. The wires head into the rear mudguard, then follow a crimp in the side until exiting through a hole in the rear, into the light fitting. This wire is then connected to another metal clip, basically wedged into a bent flap, held in place only by the “springy-ness” of the metal itself…

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The wire going into the rear light fitting looked a bit corroded, so I took it out, sprayed some white vinegar on it (helpful for oxidation), dried it, rubbed it with some steel wool. The copper colour shone nicely, so I “re-twizzled” the strands, rubbed the metal clip with the steel wool and reinserted the wire. Crossed my fingers. Tested it it again. Nothing.

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Then I removed the bulb and filed a tiny bit off the bottom to ensure good contact. No joy.

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I now removed the wires from the dynamo and did the vinegar, steel wool and “twizzling”. Crossed fingers. Tested again. Nothing.

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Not to be deterred, I removed the bulb again, and found bits of spider eggs or some other insect leftovers. Blew those out. Another round of vinegar, steel wool, scraped a bit with a screwdriver, dried it, sprayed a bit of WD40 on it.

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While I was at it, I sprayed a bit of WD40 on the metal clip and the wires at the dynamo. A bit of WD40 often works wonders.

Screwed the bulb back in. Crossed my fingers. And it worked!

A well earned cup of tea followed. If only every Sunday were so productive!

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Velobrico Workshop: 1930s Wonder tandem (update 1)

While trying to find some info on the Wonder tandem, (it’s easier to research on the net in winter than brave a cold workshop), I came across this great forum, all in French, related to this manufacturer from St Etienne.

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Some fantastic advertising posters.

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A few pictures of tandems, but Ravat models, not Wonder. This one looks pretty similar to mine. Similar derailleur, “gents” saddle at the front, wider “ladies” saddle at the back, same tool pouch, mudguards, but it has a split down tube and the top tube carries through to the rear seat tube.

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From the look of these pedals, mine aren’t original.

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I imagine myself pretty much as the chap in the photo below, casually pointing out a route on a map to his female companion.

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I was curious why the chain goes all the way from the front chain ring to the freewheel on my tandem. Typically I have seen one shorter chain between chain rings, and another between the rear ring and the freewheel.

The advert above says that this is how Ravat tandems were deliberately designed, along with a short rear wheelbase and thin lateral tubes, which “improves stability, rigidity and performance”. That’s a bit of a vague claim, and I don’t see how the chain length would help with that, but when I ride it I guess I’ll decide for myself!

Once I start on the restoration in earnest, I’ll be sure to reach out to the forum members. Looks like the only place to go!

Treasure hunting

I recently picked up a couple of cone spanners made by Sugino, the Japanese component manufacturer, at a second hand store in Switzerland.
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They are in immaculate condition and only the 13mm spanner seems to have ever been used (maybe once?).
Does anyone ever use the 14 or 16mm spanners? I have never owned a hub that uses them. Would be great if 13 and 15 came on a single spanner, as they seem to be the most common, but then they’d sell fewer tools!
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I already have a bunch of cone spanners but these will go nicely with my 1985 all-Japanese Fuji Del Rey. It has Sugino cranks after all. They are really nicely made, and in far better condition than the Fuji itself…
Any idea when they date from?
I’m guessing 80s-90s, as the internet isn’t yielding much in the way of info.
Remember, you can never have too many tools.
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