Converting my Diamondback bike, which direction?

[dermbrian]

I have a Diamond back STI-8, which is a hybrid or 'city' bike with moderately narrow tires (not mountain bike style) and an 8 speed internally geared rear hub. It's pretty efficient and I bought the large frame size, so it also is right-sized for my height.

What I would like to do is add whatever e-bike components that would be best to make it electrically assisted. I still want it to be usable as a pedaled bicycle. Let me give a little more info about what I mean by that.

1. When I want to ride it without any electrical assist, I'd like it to be just as rideable as it is now. No drag from the installed components when turned off.

2. When I want the ride to be easier, I would ideally want the motor system to make the riding easier, not do it all for me, most of the time. I'd want to be able to really extend my battery-assisted mileage by putting in my own assistance to the battery and motor.

..and finally....

3. I'd like a top-end to the battery assist in terms of speed. Let's say 12 mph. If I want to ride faster, I have to pedal and would like no 'drag' from the battery/motor system preventing me from doing that.

Does such a system exist? I have no desire to ride 18+ mph. I can't ride that fast on my own except for the briefest of times. My bicycle is not designed to be stopped from such speeds, either. I just want something to help me go several miles on mostly residential streets to the grocery store and work (3 mile ride), arriving there without sweating unduly from the effort.

If and when the ShareRoller system goes into production instead of crowdfunding, I'd like something like that since it doesn't modify the bike and is easily brought inside at your destination. But since that may never happen, I'm beginning to look at other options.

Brian

 

[tomjasz]

1. When I want to ride it without any electrical assist, I'd like it to be just as rideable as it is now. No drag from the installed components when turned off.

ALL drives will have some drag. I'd suggest a small front gear drive motor kit. BUT there WILL be drag. The large and heavy Magic Pie direct drives have little drag but others vary.

2. When I want the ride to be easier, I would ideally want the motor system to make the riding easier, not do it all for me, most of the time. I'd want to be able to really extend my battery-assisted mileage by putting in my own assistance to the battery and motor.

Sure, with a good system you will have PAS, pedal assist. Better, read more expensive, torque sensing systems will likley do a better job.

..and finally....

3. I'd like a top-end to the battery assist in terms of speed. Let's say 12 mph. If I want to ride faster, I have to pedal and would like no 'drag' from the battery/motor system preventing me from doing that.

Battery will not dictate speed, directly. With the speeds you want 36V will be more than adequate.

I'd go look at eBikes.ca, poke around their site. They have some great front kits and great small stealthy motors. Torque sensors are options. (Link Removed - No Longer Exists)

 

[dermbrian]

ALL drives will have some drag. I'd suggest a small front gear drive motor kit. BUT there WILL be drag. The large and heavy Magic Pie direct drives have little drag but others vary.

''

I had read on another post that mid-drive motors (at least some of them?) have a clutch mechanism so that the motor is disengaged under certain circumstances, so there shouldn't be any induction to create the drag. And the ShareRoller update yesterday in the threads here mentions that they've had a redesign to allow total disengate their friction drive wheel when you wish to ride unassisted.

Also, I realize that the battery would dictate top speed, but on a throttle system, wouldn't the throttle setting dictate the speed? Set the throttle to 12mph on flat land and what happens if you try to pedal 15 mph? It's easier? It's just as hard as an unpowered bike? It's harder because your 'fighting' the motor?

Brian

 

[tomjasz]

Yes the clutch disengages, in my mid drives, but there is a bit more drag than an unmotorized bike. Pedal assist can be set on most bike to suit the level input you put in and the amount provided by the motor. PAS is the term. There are torque sensors for hub motors that can much more accurately read your input and give you the level of assist you want as well as speed. Using the throttle while pedaling on every system I have, over rides the PAS and torque. I suggest the best thing to do is visit a shop that allows test rides and get a sense for how they work. Trying to intellectualize the workings without experience is quite confusing to most. It was to me.

I apologize, I typically don't follow Indiegogo systems and don't consider any friction drive ready for the market. There have been at least a half dozen or so flops over the last 5 years. Parts are sometimes slow to arrive for common systems. I can't imagine the frustration of a new adaptation. After a year in the market with a few thousand sales and reports...maybe.

Go for a ride to get the best overview. If you were in SE MN I have a half dozen builds to try. Not to sell, just my rides.

 

[harryS]

I know Thomas has put together and serviced a lot of Bafang mid drives, while I've only done my single BBS02, and a couple of geared hub motors, but I want to add my view. I think what riders are feeling on these two drive systems is the extra 14-20 pounds added to the e-bike. I can certainly feel that when riding my e-bike w/o power vs my regular bike on my mostly flat routes.

On m geared motor, there's certainly some drag. Give it a yank, and my drive wheels only spin for 10-15 seconds where an unpowered wheel will go a minute, but I certainly don't feel it on the road. On my BBS02 mid drive, if I pull off the chain, the crank free wheels just like a regular crank to me. I believe drag is minimal. My lightest DIY e-bike kit has a 6 pound motor. When I use a 3 pound battery, it rides like it did prior .

My riding style is probably like Brians, except I don't have to be anywhere on time when I ride a bike. Typical speeds are 12-14 mph, usually at low or no pedal assist. I alternate between several home built ebikes or a regular bike, and always need a shower when I get home.

I have limited experience with front drive, although I own a fatbike with a front/rear geared motors. That's a heavy tank of a bike. My comment would be that it's not easy to find a light weight geared front motor, but this looks like a good deal at its current sale price. Just my opinion though, as I've never seen the kit, but looking at the pictures, it should be fairly easy to install. You don't even have to pull off the pedals to install the pedal sensor, and it has a thumb throttle. It's not a fast system, but should do what Brian wants. He should avoid the 1000W direct drive motors which start around, what 12 pounds, do have drag, and enough power to rip alloy alloy forks apart,

Otherwise, it's a Bafang BBS02 to keep the integrated hub. If Brian keeps it in PAS1-PAS2, where the motor delivers 100-200 watts, the hub should be fine. On my BBS02 bike, in high gear, PAS1 is good for 12-14 mph. I also ride it in PAS0 and use the throttle only on hills.


.

 

[tomjasz]

Thanks Harry! Well thought out, and I'm still learning. Old dogs and new tricks...

The eBike.ca kit is much the same and I'm confident about their warranties. I have a small, 250W, geared hub drive and it has very low drag but is a rear. I will build a front geared hub this season but will likely look to MAC. I just read the recent Grin thread here and the new front motor build. I really like my front drive bikes. I don't understand the reticence to build one. Unless there a lot of hills to ride. But for a daily rider mine just works. It DD so the drag is more noticeable. IMO if someone wants a non electric ride they should consider a second bike. BTW we ride two BBS01 350W bikes nearly daily around a local park trial that's about a 7 mile figure 8. Top speed 20MPH average speed about 12-14. I love those bikes. They ride like a bike and the bike braking system is adequate. I wouldn't hesitate to build another 350W ride.

EDIT Having done customer service I tend to maybe overstate the drag, but have had customers that expected less. That's why I suggest test rides at a good shop. AND maybe consider a second bike from a good eBike shop. My only caveat with ready builds are the batteries. I'd want one that can use an off the shelf replacement, not proprietary. IF that exists...

 

[Al P]

This past spring, I converted my Mongoose hybrid mountain bike to a front drive electric using a 500w motor. Most of my riding is in a mountainous region with lots of hills, so the power is a necessity. There is no perceivable drag on the bike, and I have ridden it on relatively flat terrain with no pedal assist. The only difference is the added weight of the motor and battery (about 21 lbs.). I average about 12-14 mph but the bike can do 22 mph. It also has a dual throttle. While pedaling, it acts as a full speed booster. While coasting, it is variable, which gives you flexibility.

The top end to the battery assist will depend on the gear you are in. In higher gears, you may be able to do 20 mph, while in lower gears, 12 mph may be all it will do.

 

[tomjasz]

This past spring, I converted my Mongoose hybrid mountain bike to a front drive electric using a 500w motor.

Thanks Al! Which kit?

 

[TrevorB]

With 8spd hub 350w middrive eg BBS01 should be OK but 750W maybe a bit much for hub, do your homework.

 

[tomjasz]

With 8spd hub 350w middrive eg BBS01 should be OK but 750W maybe a bit much for hub, do your homework.

Any IGH hub with a BBSxx should have the Gearsensor installed. If it is there will be few problems. The BBS01 and BBS02 will be fine. You'll not find an 01 in the USA. There are positive reports with the BBSHD and IGH as well, using the gearsensor that positively shuts down the motor for the shift.

 

[Al P]

Sorry for the delayed response. Leed makes the kit. The motor is an 8Fun geared type.

 

[tomjasz]

Sorry for the delayed response. Leed makes the kit. The motor is an 8Fun geared type.
View attachment 13870

Thanks! Nice ride! It appears to have the nice sealed controller similar to what ebikeKit uses. I have a kit with the similar controller. Nice and clean looking too!

 

[Al P]

Thanks Tom. The parts work well together. I haven't experienced any glitches, and I really appreciate the much lighter weight compared to my Evelo, which is an excellent bike, but a bear to lift onto the rack. Leed is an excellent company as far as customer service goes.