Catrike 700-E build

Any close ups on your throttle, and are you selling them?
 
Hi Matt,

Beautiful bike, very elegant!

Very elegant and mostly off-the-shelf parts. You are close (if you are not there already) to being able to offer pretty complete kits, using your stock parts, to fit most bikes.
recumpence said:
CT700--- Two stages to the wheel.
How much reduction (first stage and second stage)?
 
Hi Matt,

recumpence said:
First stage--- 4 to 1.
Second stage--- 3.5 to 1.
Thanks! Please let us know how the belt holds up.

In case you are interested, assuming the first stage is 5mm 20t/80t according to this calculator with the shafts 3.42 inches apart (450 mm belt) there are 6 teeth meshing but with the shafts 5.28 inches apart (535 mm belt) there are 8 teeth meshing.
 
Well, I finally got my speedo wired up and programmed. I did some testing and have some hard numbers for you.

First, it maxes out at 26mph with the current gearing, just as I thought. Second, in real world riding, It averages 14wh per mile. That is with some full throttle blasts, climbing hills, and generally cruising around (no pedalling what-so-ever). I can nurse it a bit and improve that quite a bit. Heck, going to a 3210 would probably drop 1 or 2 wh per mile, most likely. But, I wanted to give some real world numbers for you.

Also, I have over 100 miles on it and it has been totally problem free, no loose set screws, no broken belt, just cruising. :)

Matt
 
Hi Matt,
recumpence said:
Anyway, the efficiency is great, the weight is low (somewhere around 55 to 60 pounds if I had to guess) and it is quiet. The video sound sucks. It seems to amplify the high pitch frequencies. It is actually almost silent.
Substantially quieter than your other ebikes?

If so how much of that is attributable to the enclosed belt first stage and how much is attributable to the lower rpm (drive noise)?

Is the lower kv motor substantially quieter (motor noise)?
 
The sound is lower due to both the enclosed drive and the lower RPM.

I found out something interesting....... On very efficient builds like this (my recumbent would qualify also), everything makes a substancial difference. For example, previously, I was averaging 14wh per mile with average riding. I just got back from a 5 mile ride with mixed riding (some casual, some not so casual, alot of full throttle, some pedalling, mostly no pedalling) and averaged 12wh per mile. Hmm, the only thing I did was increase tire pressure from 65 pounds to 100 pounds. That is a huge improvement!

Anyway, I just ordered a slipper clutch from McMaster. It will need to be modified for this application. However, I was to give it a shot. I really want to make this trike something I can just let anyone ride without coaching about belt skip, or overamping the controller (if I go to a chain). It would be nice to just say "Pedal first" then "Have fun!". I am very close to that right now.

At any rate, I have let many people ride it. I just talk to them about belt skip and they are fine. This system is so refined, however, that I want to eliminate the last item of any question at all and that is by way of a slipper clutch to protect the driveline and controller.

Matt
 
My dear friend Matt :)

Have you given some though to somthing akin to a throttle lock out with a cadence sensor on either the crank or the wheel (or an idler, etc)... so a minimum speed would need to be reached before the throttle would engage?

Would eliminate the need to explain "Pedal First" :) and it would likely be a crudload simpler to engineer than a slipper clutch - simply interrupt the throttle return line or hold it to ground.

Tire pressure will not only make the world of difference in terms of general efficiency and ride quality but, it kinda makes the slipper un-needed... at 100psi, I'm betting you will spin them before you slip the belt drive ?

-Mike
 
mwkeefer said:
My dear friend Matt :)

Have you given some though to somthing akin to a throttle lock out with a cadence sensor on either the crank or the wheel (or an idler, etc)... so a minimum speed would need to be reached before the throttle would engage?

Would eliminate the need to explain "Pedal First" :) and it would likely be a crudload simpler to engineer than a slipper clutch - simply interrupt the throttle return line or hold it to ground.

-Mike
Yes, I have.

The main reason for the slipper is multifaceted. First, it is only a $67 part that I then modify. Second, a slipper also is RPM sensitive in that at low RPM, it will slip relatively easily, and at higher RPM more wattage is required to slip. I am not sure why this is. But, on my recumbent, it works fantastic! They are also easy to adjust and tune. Besides, it will protect the driveline from overloading.

I am with ya, though.

Matt
 
Gosh, looking at the quality of your work and level of craftsmanship is like looking at the inner workings of a lunar lander 8)
 
Thanks. :D

I am really liking the level of performance, efficiency, light weight, and overall useability of this trike. Tomorrow I plan on taking it for a 30-40 mile ride. I will do a bit of pedalling. But, it will be mostly motoring. I will take it to the neighboring town that I grew up in. I plan on touring all my old neighborhoods, back alleys, and friends houses I used to pedal to as a kid. I think this trip will take on a whole new meaning on a bike. I mean, I have driven these roads hundreds of times since growing up. But, I have never done so on a bike. This should be interesting. Oh, I have always wanted to rerun a lap around my neighborhood in the same way I did on my go-kart as a child. This thing comes really close in feel to a kart. So, I will do that lap and see if it brings back memories.

At any rate, I have never gone so far on one of my E-bikes before. I think it is about time I do some serious touring on it.

Matt
 
Do you feel that a SRAM DD 3 speed rear hub would be of any advantage ?
 
Yes, I do, actually. However, not for dual right side drive (though that is cool). But, for higher gearing for pedalling. I can very comfortably pedal up to 28mph. I can do 30mph without spinning out. But, that is not comfortable. This thing is geared (motor gearing) for 26mph on a full charge. So, at high gear, I can pedal with it just fine. However, I would love to gear up for 30-32mph. That would require taller gearing. That being said, all I really would need is a slightly larger chainring to achieve that. Besides, the only reason I need low gearing is to pedal only if I have an electric problem. Low gear in this thing is LOOOW. The smallest chainring is 32 tooth. That is also the largest rear cog. So, I can go as low as 1-to-1 on the pedal to wheel gearing. That is awesome for hill climbing without a motor.

Anyway, I am babbling.........

I will be taking the 700 for a 30 mile tour this afternoon, after work. I will post back my findings on how well it performs in long touring rides. If it seems comfortable and capable in that roll, I will set it up for long distance touring. Heck, I normally stay so close to home, I do not even carry a spare tube or pump. That will, obviously, have to change if I do much touring, especially with these skinny high pressure tires. Oh, ya, this thing uses funky 16 inch by 1 inch Presta front tubes. Oh, joy. I have to drive nearly an hour away to pick up those funky tubes. Hmm, I guess I should stock up. :D

Matt
 
Matt,

video plleeeaaaaseeee?????


D
 
Today I installed a slipper clutch on the 700. It is fantastic! I love this thing! It completely eliminates the worry of over throttling it and skipping the belt. In fact, if I want to, I can just nail the throttle and let the clutch slip up to speed. No problem at all. This thing is fantastic! Now I can let novices ride the trike without any worries about coaching them how to protect the driveline. :)

My wife is out of town with the camera. So, I will post pics later this week.

Matt
 
Your recumbent and that build is the bike that got me into this, nearly a year ago!

I'm very excited to see you re-visiting this idea, now with the expertise of 2 (I think) years of building Ebikes. Such refinement.

I've always had the sneaking suspicion that the slipper clutch was worthwhile. Heck, I even picked up a bag of those Bell washers you used in the first slipper clutch, just in case that turned out to be the best idea after all. It never occurred to me that you could just buy one!

I love hearing about your experiments, I look forward to the day when my FS recumbent is ready to show. I've got the battery-pack side just about licked. First a hubbie, then on to cutting and welding a perfectly good FS bike into the e-cumbent of my dreams. If it comes out 1/2 so well as this one, I'll be well-pleased.

Katou
 
so would the slipper clutch help to save an internal hub ? ..... as in a SRAM DD
 
Hi Matt,

recumpence said:
Today I installed a slipper clutch on the 700. It is fantastic! I love this thing! It completely eliminates the worry of over throttling it and skipping the belt.

Matt
After using this bike how many belt teeth meshing do you think would be required to prevent slipping without the clutch?

How much custom work did the clutch require? Maybe you should offer them for sale?
 
If the belt did not skip, the torque would brake it. Only a chain can take the torque. That is the problem.

Electric motors like this have so much torque, you really need to rely on secondary systems to reduce the huge shock on the driveline for protection. However, with RC ESCs, it is easy to blow them if a current limiter is used because of the phaze current problem. A slipper clutch is not perfect in that it wastes power when slipping. That is fine, however, because it does not slip very often. In normal riding, you would never know it is there. Only under very hard use does it affect anything, and what it affects is exactly what needs to be done (bleeding off excess power). :)

The only modifications I had to make was a custom pulley for it. After some more testing, I plan on making the pulleys for this clutch a stocked item for resale along with stocking this particular clutch. So, these should be available through me in less than a month.

Matt
 
Wow! 12 kw/hr avg. is an amazing accomplishment!
What Matt, you are not going to be designing and building your own slipper clutch!!?? What the heck, I expected more from you man. :lol:

I guess we have to wait until the missus gets back to see a pic of that clutch. :x

I am confused on your reply on whether the slipper clutch will or will not save an internally geared hub. It will give the user the ability to control torque load to the rear hub correct? I will have to seach mcmaster for more info on this, thanks Matt.
 
The slip clutch, or torque limiting clutch will save whatever part of your drivetrain that you want it to.

If you want to limit the torque on the Dual Drive hub, then you set the slip clutch to whatever torque you think is safe.

I think one of the real tricks here is setting the thing. Determining the dynamic torque is going to be a job.

The simple way is to set it tighter and tighter until something blows, but that's a bit expensive in parts.

Or, you could set it for the lowest tolerable level of acceleration and rest easy. It's dialing in the between part that's tricky.

Any ideas on setting it to a torque-at-the-wheel standard? I guess you could put your rear wheel on a dyno and do it that way.

I'm totally using this idea, it's awesome. Thanks Recumpence!

Katou
 
I just got in from a 10 mile ride. The clutch is staying in correct adjustment and it just works........... PERIOD! No issues, no objections, ho hassles, just fun!

Only problem is, I am finding myself on the throttle ALL the time now! So, my efficiency is down. Ironically, it is not down by much, however. But, again, I am on it so much now that my range is affected slightly. Bear in mind, that is from more throttle capability (and me taking full advantage of that capability), not caused by the presence of the clutch in the system. If I am tame with it like I was before the clutch was installed, the range is still fine.

At this point, I feel the clutch has proven its usefulness. I will be stocking these ready to go very soon.

Matt
 
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