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!

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.

 

Another Mixte

New front derailleur is at the back. The other one had been rubbing on the chain for a long time and is almost warn through. Both are ....

the Suntour Spirt "normally in high gear" type as described here in Frank Berto's book The Dancing Chain

Chain before replacement.

Completed bike

Milk crate = Preston Pannier mounted on custom adapter. There are 2 3d printed crate locaters, files for printing them are available on Thingiverse here.

Also 3d printed are plastic bushes for the Suntour thumbshifters.

Reflector came from the donor bike.

Chain after fixing

Original brochure from 83 / 84 Repco Catalog

This bolts to the underside of the rack to keep everything in place

Twin Thumbshifters

Donor bike

This bike (Repco 83/ 84 mixte) was listed for sale on Facebook marketplace for $20.00, and was about 1km away from where I live. So I was able to ride to pick it up, and wheel it home, riding one bike and wheeling the other. 

I was quite pleased to find it had interesting Suntour gears on it, and despite some plastic bits broken, I was able to fix them. It now rides quite well. I didn't touch the brakes: all the fixing was in the drivetrain, and I regreased the bottom bracket and used the donor bike chain. Very pleased with how it turned out and I like the sombre dark purple colour.