Best frame for CYC motor?

[dudgggg]

Hi so I want to build a bike around the CYC stealth motor and I am looking for the right frame.

I want to be able to mount the motor inside the frame triangle as shown in the second variant: https://www.cycmotor.com/mounting-positions

I did some research and the builds that I found usually have the motor very exposed, it also looks crude in my opinion.
https://www.emtbforums.com/community/threads/vitus-mythique-cyc-x1-stealth-motor-build.23218/

Please advise and help me pick the perfect frame for this build. It should...

- be available for $3000 or less, more only if it is excellent
- have full suspension
- 29 inch
- preferably no carbon
- decent space in the frame triangle

I am currently considering:

- Specialized Stumpjumper Alloy, obviously because it's from Specialized. Kind of ugly though.
- Cube AMS 100 C:68 Race, this looks great because the tucked in suspension at the top tube.
- Focus Jam 6.8, also neat suspension setup. Not sure about overall space within the frame triangle.

Would really appreciate it if some knowledgeable people can look at these and help me decide or even can recommend something different altogether. Thanks in advance.

 

[scianiac]

Have you considered looking around for used bikes, you can get a lot more bike for a lot less and considering you're on this forum looking at doing a DIY conversion you probably have the skills and willingness to do any service on the bike if needed. Or even if not the cost to do a basic service on a used bike should be way way less than the amount you save.

For fitting the motor inside the frame maybe try a bit of photo work, assuming the picture of the bike you're looking at is the correct size, you can scale the picture with the rim size for instance and then draw the rough size of the motor to see how it will fit. In this case new and used bikes both have issues, most new bikes only show pictures of one size, often medium but you don't really know. Used bikes you have a picture of the actual bike but sometimes people are bad about taking side on pictures.

 

[Kiwago]

I suggest somethink like these two from photo. Quite old design. Both frames are aluminium. There is plenty space for battery.

 

[dudgggg]

I'm sure these would be good bikes but they just look really uninspiring and also kind of cheap. I'd really like to get a new bike because it's just so clean and high tech looking, I want something eye-catching and not generic. Honestly thinking about it, for an amazing looking bike I'd just backpack the battery and do the conversion even if the battery doesn't fit on the frame so I'm open to some frames with tighter layouts. Looks-wise I could go with a cannondale jekyll but with that design scheme the suspension might even get in the way of the motor and it's just too expensive for a frame where it might not fit right. It would have to be close to perfect.

I am willing to go used if it's something cool and somewhat unique, maybe even retro looking. I'd really, REALLY want a Yamaha Rotec mountain bike. For that, I'd pay some serious cash if it came up but I literally cannot find one example in my country.

One outrageous design that I like is the Nicolai Lambda. I could probably acquire one but I have no idea if the geometry even makes sense. I also read these are massively heavy and again, the suspension would get in the way of the motor. :|

I'm also annoyed the Canyon Orbiter isn't put into production. If no good option comes up, I need to re-budget for this project and do the whole thing myself.

That option would be to literally design the frame myself (ideally with some help/inspiration), then reach out to a metalworking shop and commission my own frame. I suspect that this would exceed $5k for the frame alone and it would cause the project to take more like a year than a few months, and $5k was about the budget that I had planned for the whole bike with motor. If someone here has CAD software reach out to me, I am willing to put the craziest frame concept into reality. It should look like a Monotrace bike, but made of aluminium and best would be if it had a wild suspension linkage like the Structure scw 1.

It should be a 60:40 mixture of looking nuts and being practical.

 

[scianiac]

I think looking at used frames, even if you have to ship it is probably a pretty good bet to get something that is both crazy looking, reasonably priced, and of good quality. I actually just picked up a 2010 Santa Cruz V10 and it is all of those, looks cool, all high quality parts (even if older), reasonably priced. With a used bike you have all of history to add variety. The weight is the downside but it's not totally a downside, the bike is going to be heavy in the end after I add a motor and batteries so a stronger frame is not a bad thing here. And I also think a rather heavy bike with lots of weight down low (motor and battery) counteracts many of the disadvantages of older geometry while still keeping it's advantages. Having a super long, slack and low bike with big wheels doesn't seem needed when you have the low CG and lots of weight for the suspension to work against. At least that's my theory, well see how it plays out.

The wheel size is a tricky one (older crazy bikes often are 26in) but I also think that's should be partially based on things like size. Currently I have a size small bike with 29in wheels and honestly it's kinda meh, it just feels awkward. If it was a size large I bet it would feel just about right but I can't get any taller. The roller over is a thing but also remember carrying speed is less important when you have a motor and you do loose maneuverability.

Having tried the backpack battery I'm mostly against it at this point, better off making a custom battery even if you have to wedge cells everywhere. Yes with the backpack you can move that weight but it still moves the CG up, is annoying to get on and off the bike, and just makes your legs tired faster even when you aren't pedaling.

 

[Deleted member 82754 (removed by user request)]

Hi,
Bought a used Salsa Rangefinder (large 29er) for my BBSHD and found the horizontal portion of downtube would not allow it.
Purchased the CYC Stealth and it fit nicely inside the triangle along with the battery. Loads of clearance for logs and water crossings. I was concerned with it not being full suspension, (I am over 60), but the 29" wheels do a pretty good job of absorbing the impact from trail conditions.
It has proved to be a very strong motor that has pulled me through everything I have thrown at it. If I can stay on it, it will climb it.

 

[Deleted member 82754 (removed by user request)]

Update...one year later, the frame has broken. I am considering good old fashion steel.

 

[FuzzyWuzzy]

Wow, how did that happen? Any severe load?

 

[Deleted member 82754 (removed by user request)]

I found it while performing a winter tear down and maintenance, about 900 miles on it this summer, mostly on trails and slightly technical. Ya, it really bummed me out. Busted it up in one season!
I guess with my weight (95 kilo) plus battery and motor, and riding style, this created enough load to crack it. No major loads IMO, no trailer hauling or nothing like that. Not doing "air" or anything like that.
Most opinions say it's not worth fixing and some say no problem! I have since purchased a steel frame and transferred the components.
large surly krampus will not fit the CYC inside the triangle. I am actually "diggin" the "no suspension" front end contrary to my original thoughts .

 

[DanGT86]

The fact that the break is right on the heat effected zone of the weld makes me think this frame was doomed anyway. I can't imaging the motor had anything to do with it other than maybe increasing your avg speed when hitting bumps. That is a bummer for sure.

 

[2old]

Salsa should replace the frame (but probably won't if they know it was converted). It's almost certain the frame wasn't heat treated properly.

 

[Deleted member 82754 (removed by user request)]

Salsa warrants for 3years to the original owner. I bought it 2nd hand.