Compact Long Wheelbase Front Wheel Drive

 

Unmodified Cruzbike Quest in the 

forest near Aireys Inlet

 

For more than a year now I have been experimenting with riding and upgrading front wheel drive, moving bottom bracket Cruzbike Quests. Although I once made a Cruzbike Kit moving bottom bracket bike, this current bout of enthusiasm for mbb's has been my longest. Working with Cruzbikes has made me more confident with disc brakes, and moving bottom bracket front wheel drive, and unafraid of using these in bikes I make. I'm already quite comfortable with tailboxes, and both my Cruzbikes have been upgraded with tailboxes I've built, plus dynamo front lighting. As well I've made a custom chainstay to alter bottom bracket height. For me, tailboxes are a no-brainer on recumbent bikes, and their load carrying capacity transform the bikes from exercise machines to practical transport.

Quest with wooden tailbox with decoration from old t-shirt

2nd tailbox built is lighter and intended to be more aerodynamic

High bottom bracket chainstay is the latest mod to the "fast" tailbox Quest.

 

Its worth stopping here and maybe see what is for and against my current Cruzbikes and current leaning trikes - I'm trying to make a best of both worlds bike, somewhere in between my leaning trikes and the Cruzbike.

Daily driver, this was what I still ride regularly for load carrying, but it has..... 

 

existed in other forms including this 2 wheeled bike version. This was its hour of glory and I rode it to win an OzHpv challenge seniors division title. Glory days were not to last as the rear wheel frame later broke!

Probably the reason I'm riding Cruzbikes is their engaging ride. Because arm force is used to resist leg force when riding, they take a certain amount of subconscious mental effort to ride, which induces an enjoyable flow state: the Wikepedia entry describes it, "One is most likely to experience flow at moderate levels of psychological arousal, as one is unlikely to be overwhelmed, but not understimulated to the point of boredom". Before regularly riding Cruzbikes, I got the same feeling from riding a bike while wheeling another at the same time, a regular occurrence when ferrying bikes for Wecycle.

So the biggest problem I had with the Quests I have fixed, and that is load carrying. But the problems remaining are

*  Right shoulder soreness. Its only since riding Cruzbikes regularly that I've had this, and I can feel my shoulder twinge when playing pool, putting in effort when paddling (surfing) and even reaching for the alarm clock. I'm not sure its related to the Cruzbike, but I can't think of anything else that could be causing it.

* Hard to get on and off. On my long wheelbase bikes I can swing my legs over onto the pedals as I'm running along launching the bike. Although a vastly different bike, the  Rans X-Stream has this quality too. On the Cruzbike the steerer stem is just too close in for legs to swing over.

* Its necessary for the handlebars to be quite wide on these bikes, and therefore slightly less aerodynamic due to a wide hand position. Having a wide handlebar helps make leverage for the arms and reduces arm strain.

But the good points are its manouvreability, that it can be folded up for carrying in a suitcase, and that there is a good amount of weight on the front wheel which helps traction. 

On the other hand, in my long wheelbase bikes there is little or no (engaging / shoulder wrecking!) force from steering in the arms, the front drive wheel is lightly loaded and can slip, and although the bike does separate, it stays in fairly big and wouldn't fit in a suitcase. And manoeverability is crap, you can't pedal and do much steering at the same time. But the handlebars are quite narrow which keeps things tight and aero.

So to cut to the chase, in my spare time a few months ago, I started building a new front for my leaning trike. Work has been a bit haphazard up till recently, but now I have a bit more time and something to show! I have actually built something like this before, it was a short lived machine

 

First version of forks without brakes. There is a spacer / open washer brazed in on the drive (lower in the pic) side dropout, and this is to ensure the chain doesn't rub on the fork.

At this stage I put things together but didn't actually ride this version.

 

 After making the parts and the layout machine, I did some 2d cad drawings to estimate where things might go. I realised that the handlebars had to be elevated to allow me to swing my legs through, and having some dimensions to guide assembly would help.

 

After that, I started work on a rideable, relatively solid version. I still used the flaky bottom bracket though!  

 

So this version took me around the block once! By the time I'd put it together, I had added a brake to the back of the fork - the intention is to have one V and one disc brake on the front wheel for the final version.  This one was sort of cobbled together and after riding it, I drew up what the final version might look like. Some inspiration came from my son's Surly longtail - for the child's handlebars on the back they just use a 28.6 mm seat tube which is the same diameter as most threadless fork tubes - so standard steerer components (ie stems) just fit automatically. I found a few parts in the shed and on bikes which were compatible. The next bigger standard tube OD is 31.8mm, and I had a few tubes that size as well. Today 2 bikes were donated to Wecycle, an orange and a red one. The orange bike was donor of a few parts to the red one, which my friend Myy fixed up. And I took the orange one home with the intention of using the seat - tube and bottom bracket or down - tube and bottom bracket parts in the new build. I've also ordered a new fork with built in disc brake mounts - see how we go with that.

 

 

 

Potential new moving bracket layout and 

an equivalent fixed bottom bracket bike. These are about 220mm shorter than the current fixed bottom bracket version, as the crank and seat are shoved forward, so the rear wheel frame can be shorter.

Update July 6

Today I went up to the local cafe on the bike and it went surprisingly well. I can get on and off it smoothly when its rolling and accidentally took a less cautious route there which involved some road riding. After I'd just left the cafe, a friend called me to say some stuff I'd left behind was in her letterbox. So I said I'd go and pick it up then. The extra 2-3k of riding were welcome, and I rode them cautiously on bike paths. Going up a short steep hill it started making strange noises and I discovered soon after the bottom bracket was creeping sideways. But I got home fine with more cautious riding.

Noooooooo!

 

Regards

 

Steve Nurse 

Moebius strip bike

 Before launching into this post I wanted to show a few pics of a moebius strip. It would be best just to make your own though! Cut a strip of paper, bring the ends of the paper together, twist one end of the paper through 180 degrees, and then join the ends. Here are a few pictures.

Moebius Strip

Another view

Strip as mounted in the bike. Imagine the fingers rotating and the mark and join moving across the photo as they rotate.

Chain with twist in top (drive) side.

 When my friend George passed away, his widow Christine gave some of his bikes to me. These were Linears, a bike made in the USA with a long, cherished back story, dating back to before 1985:  before most modern recumbent makers. I sold 2 of George's Linears to raise funds for OzHPV, the Australian Human Powered vehicle association. 

A third Linear from George and Chris's garage was only a frame with remote steering. I spent a bit of time kitting it out with a drivetrain, gearchanger, and front and back wheels and brakes. There was quite a bit of rummaging in the shed involved, and I bought the front wheel along with its tyre and tube from a local bike shop associated with BYK bikes. 

The bike just stayed like this as a rolling chassis as I had other bike projects going. I lacked motivation on this one, so it just stayed there for a while.

Then I accidentally put a half twist ( moebius twist ) in a chain I wanted to assemble onto a bike. This was a mistake, but it made me wonder about the possibilities on other bikes.  Most of the recent bikes I've made and ridden ( like the one here, pic 14 ) have twisting chain front wheel drive, but the chains twist through much less than180 degrees.

A bit later, I found this on the web,  an actual use of the moebius form for producing an output drive on a different plane to the pedals.  My application is a bit different, its just putting a twist in one side of the chain of a long wheelbase bike. In this case, its the top (driveside) of the chain. The wiki page for mobius strips says one of its applications is to even out wear on a drivebelt, and while this is a possibility for my use of the strip, its not really my purpose, it's just to have fun and make something interesting.

Anyway, the moebius chain works, and it works when riding the bike too! The seat I put on the bike is temporary and I can only just ride the bike because my legs are almost impossibly cramped when I ride it. Debut of the bike was on a rainy Saturday afternoon, I rode most of the way around the block on the footpath though, with the awkward riding it's not super safe on the road. Next morning I rode to our local cafe and my good friend Simon filmed and photographed me on the bike.

 I will work on the seat and see if I can make it a bit easier for me to ride. Meanwhile (tada) here is my introductory video and here (tada) is Simon's video of about the third or fourth time it had been ridden. 

This bike mod is very easy to try if you have a bike with a long chain and no chain handling hardware (pulleys and tubes) on the bike, plus a quick link in the chain which can be retrofitted. This bike has about a metre between the front and rear cog centres.

Rest in Peace my Dad, David Nurse, 1931 to 2025.

 

 

 

 

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.