Cruzbike Quest Hi Racer

 

New version of Quest with 500mm chainstay and aero, load carrying seat and tailbox.

Quest with 290mm chainstay and original seat

Quest with 360mm chainstay and 16" rear wheel and aero, load carrying seat and tailbox.

Scoping - rear suspension removal

Scoping - this folding bike frame has a very cheap version of the suspension pivot in Cruzbike Quests

Trying an MTB rear swingarm in the Cruzbike. It was slightly too wide. The visible parts of the suspension bushing were later removed.

Trying the folding bike swingarm

New 500mm fork weight is 850g in steel.

And the old 360mm fork is 330g

Similar difference in pivot hardware weight: 45g aluminium from Cruzbike

versus 110g steel from MTB

Final assembly with accidental fisheye effect

Preparing for final assembly

Widening the slots at the bottom of the chainstay from 6mm to about 10 mm was done by wearing away the steel using drills, and stepping up the drill size by 0.5mm each time. Before this slotting was done, a steel sleeve was brazed over the chainstay end to thicken it and ensure there was enough material.

Lower part of chainstay done

To reduce the width at the bearing, the lip on the outside of the bushing was removed allowing it to be pressed further into the housing. Loctite secures it in place

New top part of chainstay and old chainstay

Initial measure up. With a 500mm chainstay, the bottom bracket would be in about the right position.

Hi

 

The above photos show some of the work I've put in over the last few weeks, adapting a rear suspension system from an old, heavy mountain bike to become a long chainstay for a Cruzbike Quest. The result is shown in the top photo, it's sort-of a Cruzbike Quest Hi-Racer.

I have 2 Quests, both of which I tinker with extensively. I've already made 2 load carrying seat / tailbox sets for them, and have fitted hub dynamo lighting to one of them.  They are nice bikes, and the moving bottom bracket front wheel drive system is interesting. But for me, one of the chainstays (see pic 2) was way too short, so I've made steps to change that, looking out for, and eventually finding bike bits compatible with the Cruzbike chainstay. I bought the bits home from the Wecycle shed several months ago, and now we have some action on the building,  woohoo! During construction I used the bike as a jig. By removing the existing chainstay and moving the top tube up, I was able to place all the components together before "tack-brazing" them together. Then the chainstay came off the bike and brazing together was completed before painting.

Will report later on how it rides after a few tweeks.

For now I have been around the block and noted the following.

If, in your excitement, you forget to put your taillight on for your twilight blockie on your newly modified bike, you are a doofus. I am that doofus.

And possibly more relevant, the handlebar is too low and my legs bump into it. Moving brakes, reflector and bell would help but really the whole handlebar needs to be shuffled out of the way somewhere. 

From all my handlebar stems, I sorted out potential options for improving the handlebar position, and they are at left.

Settled on this one particular stem for now but might try others

With me on it. I'm reasonably horizontal but still comfortable. Compare with pic 2. Also note the rear suspension is compressed!  I think these sort of photos are the only simple way of assessing the suspension. The tail fairing is a bit low at the top and should be level with my shoulders.