Kinetics

ICYMI: Trix

Trix The Hase Trix is ideal for larger kids with special needs – it’s the big brother to the Trets, a bit smaller than a Kettwiesel, but will fit anyone from 4’1″ to 6’3& #8…

ICYMI: Orange Alfine Brompton

Orange Alfine Brompton This custom Brompton has Alfine-11 hub gearing and a rear cable disc brake.

Speaking of procrastination, I’ve spent most of the day finishing off a frame I really should’ve finished ages ago.

But how do you like my articulated frame jig stand? It’s an old plasma TV wall mount 🙂

ICYMI: Orange Alfine MTBrompton Expedition

Orange Alfine MTBrompton Expedition This custom Brompton has 20 x 2.35″ Smart Sam knobbly tyres, an integral rack that can hold panniers, Alfine-11 hub gearing, dynamo lighting, belt drive and hydraulic disc brakes.

Geeky alignment stuff: Since I’ve been messing about with alignment and measurement this week, and people sometimes ask about it, here’s some geeky stuff about Brompton frame alignment 🙂

Firstly, the important thing with a Brompton is to ask what are you aligning? Most conventional bikes have a centre line - the seat tube, head tube, drivetrain and wheels are all in the same plane. For some things that matters, for others it doesn’t.

Bromptons are different - the drivetrain (effectively the bottom bracket) is 5mm offset from the frame centre line. You can see this most clearly looking at the frame around the seat tube. Then the rear pivot is also offset by another couple of mm from the drivetrain.

Brompton then correct for these two offsets by having their triangles offset the other way, bringing the centre line of the wheel back in line with the frame - though the drivetrain is still offset from both the frame and wheel.

I go a bit differently, I offset back by a couple of mm to correct for the pivot offset, so my rear triangles are centred around the drivetrain, rather than the frame.

So what does this mean? There’s pros and cons of both. Brompton’s way means that the front and back wheels are in line. My way means that the drivetrain is in line.

Of course it’s also possible to build wheels with a “dish” so the rim is offset from the drivetrain centre line - some Bike Fridays do this for tyre clearance reasons, ICE trikes do it for rear wheel strength, etc. Neither Brompton or I do that, our wheels are not dished. Brompton because they don’t have to, me because I want to keep clearance for larger tyres.

So, if you notice that when folded one of my rear wheels isn’t in line with the frame, that’s why - different alignment choices for different reasons 🙂

ICYMI: White Alfine Brompton

White Alfine Brompton Built with a repainted frame because Brompton don’t make white bikes any more.

Double-checking and tweaking the alignment of my wheel truing jig, while I’m in the mood. THIS IS NOT PROCRASTINATION.

Anyhow, dishing was out by about 0.5mm. Not bad considering I haven’t checked for about a decade.

ICYMI: Green Belt Alfine Brompton

Green Belt Alfine Brompton A custom Brompton with belt drive, integral rack, Alfine-11 gearing, disc brakes and SON dynamo.

A G Line Rohloff Brompton kit with belt drive.

Making things to make things: some processes are a bit time-intensive because they need some trial-and-error to get them right, so I’ve been working on making simple go / no-go gauges to speed this up.

These are a little one to get the counterboring on a dropout correct, and a dummy axle to double-check fork alignment.