The xtra cycle

10 09 2012

Regardless, now it is together, it works beautifully. The xtra cycle bolts into the drop outs of most frames. You can use spacers for frames other than 135mm OLD and to adapt to thin (stamped) drop outs if needs be. The frame I used (an old Kelly RoShamBo) has horizontal dropouts. These are cowled and required filing in order to allow the xtra cycle to be fitted as far forward as possible. Why did I want to do this?

A) I felt that with more surface area for the ‘french bolts’ and sockets to grab onto I would have a more secure system.

B) it allowed the 2 plates that sandwich the chainstays on frames that don’t have a bridge to get the best purchase.

One thing I didn’t consider prior to using a 29er frame as a donor was that the increased bb drop would mean the front of the xtra cycle would come into the chainstay plates at quite an angle. To combat this I used 2 sets of male/female conical washers.  It is far from perfect, but as I torqued the system together, the plates bent. It happened so easily, I can only assume it is supposed to occur, but obviously I will be keeping an eye for any cracks. In time, I can see the frame being modified with a bridge that is slotted to accept a bolt directly.

As I was always going to be mounting a child seat for Daisy, I needed to lock the uprights of the xtrra cycle in place. Xtra cycle make little clamps akin to seat post binders, to do this. Doing so means the seat cant ‘bounce’ out at an inopportune moment. Of course, once you lock the uprights in place getting access to the gear and brake adjustment is a little more fiddly. Should have done that bit first.

Using a 650b rear wheel pushes the clearance of the xtra cycle pretty far. In the end though, the only issue is removal of an inflated wheel. I cant see this being that much of a detriment in practice. Theoretically, a 650b rear wheel is less robust, due to decreased triangulation, so I used quality components I have good history with, 3 cross spoking and brass nipples. The Pacenti DL 31 rim (from Just Riding Along) deserves special mention for building beautifully and having a super high quality feel. It would be an excellent choice for a 650b, or 29er, AM wheel set up. The front wheel ended up being a Paul ‘word’ rear hub which is built into a mavic A317 currently. I aim to change this to a fatter, stronger rim soon. Why a rear hub? I’m using a Surly moonlander fork that uses rear hub disc offset/front brake adaptors. I wanted to use a Paul wHub as it has enormous flange width and this builds a super durable wheel but couldn’t find a fork long enough to get the geometry where I wanted it without going custom or carbon that uses this set up. Using a rear hub it gets a touch narrower and heavier, but no big deal.

The BB7’s work surprisingly well with 180 front shimano and 203mm rear shimano rotors. I had to use older style slx rotors to get the alloy centre section that means you warp discs less easily, but retain clearance for the bb7 mechanisms. I had wanted to fit hydros, but struggled to find hose for the older style xt brakes in 2m+ lengths. Actually, as these work well and allow me to use Paul love levers (my all time favourite feeling lever blade) i’m happy. An old 10, degree rise 125mm steelman stem, with wide 20 degree sweep ti bars and an old ritchey 2 bolt seatpost and magmaa saddle. Slx cranks, Aluminium chainring bolts (never had an issue with these using purple loctite and care), a 36 tooth e13 ring, 2 xtr chains, a saint rear mech, xtr 11-34 block and xtr trigger shifter (all pre-used and donated from other bikes).

So, what do I have? Well, it is a beast. Heavy, long and it yaws when loaded – I guess the way the xtra cycle attaches in a single plane, which is also low on the bike, will do that, but after a few rides, you compensate. Pleasingly, the shifting is good and doesn’t exhibit too much rub when the whole is flexing around. I used an e13 seat tube guide that helps keep the chain on, but I may add some form of guide to the front section of the xtra cycle. We’ll see. .

Daisy loves it and riding this beast is already putting some strength into my thighs. All good.

Thanks go to Practical cycles for their help and attentiveness. Good people.

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