Cannondale CX700 Stoke Monkey Conversion

[kitchenman]

Hi All, Haven't been on for a while and can image how much I have missed! I'm getting my CX700 back on the road and am opting for another Stoke Monkey conversion following the qualified success of my recumbent project. My question relates to adding the extra chain ring. Does anyone know if its possible with a Hallowtech II setup? or is it simply a matter of changing to a different crankset? All suggestions welcome.
Thanks,
Alan

 

[Deleted member 4366]

I can't see a way to fit a second chain-wheel to a hollowtech (assuming not Octalink), so simplest would be to change the BB spindle and bearings to a square tapered shaft type, then there's loads of choice. Look forward to seeing it. I dont know whether one of those new GNG crank-drive conversions would work. They get good revies on ES forum and are only £270 shipped. I'd need to see some photos of your bike to see if it's possible, or have you already got your motor and stuff?
http://www.gngebike.com/450wbrushless.htm

 

[kitchenman]

Thanks Dave. Yes. I got all the stuff. The complete bike was my first electric bike supplied by Cytronex. I then stripped off the electrics and installed on my recumbent. Now going back but with a difference I think the CX700 will perform better with a Spoke Monkey treatment.

 

[amigafan2003]

I'm seriously considering a GNG kit for my full sus bike.

 

[kitchenman]

Working on what I like to call "the boat".

 

[kitchenman]

Working out where it can go:



Where I've cut for the drop outs is no good. The motor would rub against my legs.

 

[jerrysimon]

Your projects are always interesting Alan.

Look forward to the next installment

Regards

Jerry

 

[kitchenman]

Crank added and now happy with the positioning of the motor and battery. On Monday I'm off to get the bracket made by a local small engineering company. Getting closer

 

[Deleted member 4366]

Good progress. what i found with mine was that if the bracket that holds the motor isn't totally rigid, the chain jumps. i added a compression bar down to the bottom bracket to stop the sprocket pulling down towards the chain-wheel, because the motor can make a huge force from the torque. it's the green bar in the photo below. You can just see it. Never jumped since and now very smooth.

 

[kitchenman]

Great stuff. Be interesting to see if I'll also need a bb bar... Is that a spring loaded chain tensioner? I haven't got one yet. I'm hoping its an off the shelf item.

 

[Deleted member 4366]

Great stuff. Be interesting to see if I'll also need a bb bar... Is that a spring loaded chain tensioner? I haven't got one yet. I'm hoping its an off the shelf item.

Yes, it's a jockey wheel off a rear derailleur bolted to a strip of steel, into which I tapped a thread,and I fixed a locknut on the back. It has a pivot at the end and then a spring hooked over. It took me about 10 mins to knock up. You need a chain tensioner or some other quick rigid way of adjusting the chain tension, because the chain will keep changing length at the beginning while the waxy grease works its way out. A better way would be to use just a piece of steel with a fixed bolt at one end and a jockey wheel at the other. It doesn't need to be too long, but obviously long enough to take up any adjustment. To adjust tension, you'd just need to loosen the bolt, push the wheel to take up the tension and then re-tighten the bolt. This has the advantage of allowing the chain to run more freely, but with more frequent adjustments.

 

[kitchenman]

I was hoping you had a photo! ...

 

[kitchenman]

My plastic bottle has now been turned into this rather nice aluminium bracket

 

[Deleted member 4366]

That looks a good way to fix the motor. I can't wait to see it finished. It'll probably be stiff enough, but if it's not too late, you might want to add two more pieces from the edge of the piece with the drop-outs to the other side near the top of the piece that screws to the seat tube. This will completely triangulate it and make it much stiffer to prevent chain jumping like mine did. You can always try it first, and if the chain jumps, you'll know what to do.

 

[Old_Dave]

Nice work kitchen man, tig ?


Sent from my iPhone using Tapatalk

 

[morphix]

My plastic bottle has now been turned into this rather nice aluminium bracket
View attachment 4471View attachment 4472

Alan long time no see! Where you been at? I updated the "camera shake solutions" thread with a finale to it, because I FINALLY got shake-free videos from my MD80 mini camera mounted on handlebar of my Mezzo ;-) And then, literally a week later, the tiny LiFePo4 3.7v battery in the cam died..heh. I've just took it apart in my "lab" and modified it to take an 3xAA external battery pack so now it records 10x as long (up to 6 hrs!). I've made a video showing the mod being done, will upload soon.

 

[kitchenman]

Thanks. I'm going to try it as is but I totally understand your concern. Hoping to get it wired up today or tomorrow.

 

[kitchenman]

I just made the plastic bottle mock up. Then I called in the engineers to make the piece. Its 800 grams of Ali

 

[kitchenman]

Work, work, work, I'm affraid Paul. But on a break at the moment. I'll get back onto the video thread as soon as I get this latest Stoke Monkey build up and running. Look forward to your video.

 

[kitchenman]

Hit a couple of snags. My sprockets are 3/32" but I really need 1/8". Ordered a 21 tooth sprocket from Velosolo. My chain ring is 42 tooth so that 1:2 ratio which is what I think I need. Need to sort out the mount for the pedelec sensor as I can't find the original bracket - how can that be? I never throw anything away! Anyway, here are some more pics: