SHTF build

[Leftcoastal]

Looking to build on my '18 Specialized Roll Sport Low Entry and could use some insight. Ran a few searches but would still like some feedback.

Mainly will be riding flat ground around town and would like a grocery getter to save on gas. Also something for light trail use.

The Sport has a 68mm bottom bracket as well as disc brakes (can those be retained for use?)

Is there a huge difference between mounting the battery on the down tube vs the rear?

What kind of speed and distance am I looking at on flat ground with no pedal assisting?

So far I'm looking at this component set

BBS02B 48/52v up to 1300w Bafang Mid Drive Conversion Kit Electric Bike eBike | eBay

Find many great new & used options and get the best deals for BBS02B 48/52v up to 1300w Bafang Mid Drive Conversion Kit Electric Bike eBike at the best online prices at eBay! Free shipping for many products!

www.ebay.com

And this battery
(Link Removed - No Longer Exists)

 

[PDXzap]

What kind of speed and distance am I looking at on flat ground with no pedal assisting?

I've never used a BBS02 but according to the Grin Simulator 25.8 mph. Not sure about distance.

 

[Leftcoastal]

Thanks.. If I want to up my speed what would be the best route without breaking the bank?

 

[Browneye]

You want to go faster than 25mph on a Roll? And you want to trail ride it? And haul cargo?
What is your riding experience on ebikes in general?

 

[Leftcoastal]

No experience on ebikes but I used to race bmx bikes for years and have done a good bit of mtn biking. I also have a KLR 650 enduro so fairly comfortable on two wheels with power.

It's not so much that I want to go faster but want the available power on hand. I'm thinking of also fabricating a trailer to tow. Hate to spend a bunch more money if it's obtainable now for not much more invested.

Any trail riding I'd be doing would be mainly fire trails and off road fishing and/or picture expeditions. The Roll is surprisingly capable off road with the right tires imo.

 

[tomjasz]

11T rear option, and a larger chainring. HOWEVER, BBS02B motors overheat and die if treated like a one speed.
IF you consistently shift when coming to a stop as you would without a motor it's a great motor. Changing chairing size will add speed but the BBS02B can be easily abused with large chainrings. I stick with 42T. A BBSHD is another story. Not anywhere near as sensitive. I ran mine as a one speed. 42T x 20T and got 29-32MPH. BBSHD is commonly used on commercial eBikes and pedicabs.

EDIT After looking at the links you provided I see the typical cheap Chinese battery. The only way that price is available is for the maker to use cheap generic 18650 cells.

Do a test of the vendor communication as if you have an issue. Does the seller have phone support? How long to answer a support email? I'd be leary of that battery. There are a number of replacement battery sources discussed here. It would behoove you to check them out.

I missed the trailer on my first read. This isn't the right motor for those stresses. IME.

 

[tomjasz]

The Sport has a 68mm bottom bracket as well as disc brakes (can those be retained for use?)

Are they mechanical disk brakes? Typical kits come with cable brake levers. Another pitfall are the components. Make sure you are getting a full kit, not a bare motor. Some sales on eBay make no mention of components. If you really like your current levers, consider a set of hydraulic sensors and using your current levers.

A bought a cheap trailer, at least compared to most, for $100.

25-26 mph is about all you'll get regardless of the chainring. Stick with 42T.

Pulling a trailer further stresses the motor. If using the throttle from a dead stop without having downshifted to the lower gear.

On the plus side, BBSxx are great climbers.

 

[Leftcoastal]

11T rear option, and a larger chainring. HOWEVER, BBS02B motors overheat and die if treated like a one speed.
IF you consistently shift when coming to a stop as you would without a motor it's a great motor. Changing chairing size will add speed but the BBS02B can be easily abused with large chainrings. I stick with 42T. A BBSHD is another story. Not anywhere near as sensitive. I ran mine as a one speed. 42T x 20T and got 29-32MPH. BBSHD is commonly used on commercial eBikes and pedicabs.

EDIT After looking at the links you provided I see the typical cheap Chinese battery. The only way that price is available is for the maker to use cheap generic 18650 cells.

Do a test of the vendor communication as if you have an issue. Does the seller have phone support? How long to answer a support email? I'd be leary of that battery. There are a number of replacement battery sources discussed here. It would behoove you to check them out.

I missed the trailer on my first read. This isn't the right motor for those stresses. IME.

Really appreciate the detailed response!

I'll check out the BBSHD, I really don't want to be burning up motors. Or were you referring to this one as well burning up with a trailer?

 

[Leftcoastal]

Are they mechanical disk brakes? Typical kits come with cable brake levers. Another pitfall are the components. Make sure you are getting a full kit, not a bare motor. Some sales on eBay make no mention of components. If you really like your current levers, consider a set of hydraulic sensors and using your current levers.

A bought a cheap trailer, at least compared to most, for $100.

25-26 mph is about all you'll get regardless of the chainring. Stick with 42T.

Pulling a trailer further stresses the motor. If using the throttle from a dead stop without having downshifted to the lower gear.

On the plus side, BBSxx are great climbers.

Yes they're mechanical stock disc brakes.

I'll check out components and see what's out there. So many options it's good to have a place like here to sort things out.

As for the trailer most likely be using it a 1/3 of the time. Hope to use a front and rear rack if I can get away with it.