SRAM Dual Drive with BBS02

Denman

New Member
So far I've seen one other SRAM Dual Drive with a BBS02.

I've got both, but haven't mounted the BBS02 yet.

Anyone else out there actually tried this yet and even better have some time on this?

Just not sure about reliability. Not much at ES either.
 

flymeaway

Well-Known Member
Just not sure about reliability. Not much at ES either.
My only comment is why would you need 24 gears? On a 500W 36 volts system I use only 4 gears on the cassette and on a 750W 48 volt I basically use 2 sometimes 3 when riding?

I would be concerned about reliability if you are installing the 750W 48 volt system, it's pretty aggressive....torque.

Court J.
 

Denman

New Member
Where do I begin?

So I have an investment of $200 in derailleur, $180 in shifters and $100 in the 15 feet of chain, and another $90 in a 10 speed cassette. But mostly because I'm looking for a system that will assist me up a couple thousand feet of climbing. That way I can finish the remaining 2000 feet on my own after the battery gives out.

I've always wondered why people who don't pedal much would ride an Ebike rather a motorcycle?

Reliability is the key concern. I've already ordered a spare DD3 and some KMC10.93 chain. I'll probably scale the BBS02 back to 18 watts, maybe a little less.

I bought a handful of hub drives to test and got some pretty good data from them. Unfortunately there really isn't much valuable technical data on the internet for Ebikes. Grin's simulator is pretty good for comparisons between motors but its not very accurate on things like power consumption or overheat time, at least not in the real world; its good to give relative numbers.
 

flymeaway

Well-Known Member
But mostly because I'm looking for a system that will assist me up a couple thousand feet of climbing. That way I can finish the remaining 2000 feet on my own after the battery gives out.
Curious, grade and distance? With my converted Elite Trail I can keep an 18 MPH pace with moderate pedaling at 6% grade 44T/16T. Whether or not it's accurate the watt meter on the C965 display indicates 500-600w draw on a 750W 48V BBS02.

Court J.
 

Denman

New Member
Mt Lemmon in Tucson AZ.

Ride with GPS below (not mine):
http://ridewithgps.com/routes/1725903

Loaded weight on the FS26 with a 48V 10A LiFePO4 and Mac Hub (with 10 speed and yes it's been modified to fit a 135mm dropout) is 262 lbs.

Haven't installed the Thun yet but afterwards will complete testing before mounting the Bafang.

Its pretty warm at the start, but by the 6000' mark temps drop about 15-20°. By 7000' temps drop about 25°.

I'm starting a new contract design position in a few weeks so after that my time will be pretty limited for a while.
 

flymeaway

Well-Known Member
Mt Lemmon in Tucson AZ.
Looks like an interesting ride. The average grade is 5.2%. I saw some grade over 8%. Since I've never ridden 30 miles essentially going up grade for a majority of time it's hard for me to know at what point I'd be physically exhausted. I do regularly ride 26-30 miles with significant grade changes but riding a constant incline is probably much more demanding (no break). Knowing what my 48V 750W BBS02 can do, I would probably be able to ride the majority PAS level 3 or 4 in 5th gear (assuming I didn't fold). The more severe grades in 4th gear. I'm pretty sure the issue that I'd find difficult is the heat. I'd be much happier up around 6,000 feet. My combined weight is 230 lbs.

Court J.

PS....I know Mt Lemmon, one of my daughters went to the U of A Tucson, but I never had the pleasure of riding or driving up, my loss! :)
 

Denman

New Member
So here it is a year later.......
I put about 200 miles on the BBS02/SRAM Dualdrive (DD3) - 10 speed 36-11 cassette.

The DD3 has two anti-rotation washers and they are the later thicker material. I've spun them before just from human power.

The first 150 miles I ran at 25A peak (750W rating) then turned it down to 18A (500W rating).

Heavily loaded there is a slight high frequency harmonic from the DD3. Other than that, so long as the power is properly applied the DD3 performed fine.


You can read more about it here:
http://www.triketech.com/Drivetrain/PowerAssist/MidDrive.html

Having tested different motors I found the MAC 10T to be the best match for this one.
http://www.triketech.com/Drivetrain/PowerAssist/HPV-MAC.html

I'm looking building a new trike for taking on the camper. Likely an HPV FS20 with a BBS02 & DD3. Too soon to tell.