Specialized Demo 8 BBSHD

[Yezzzzzir]

WOW you have me really inspired now! I have a 2013 demo 8 thatis sitting around collecting dust. Exact same frame and I'm considering this now..
What's your experience on how it rides? That mount looks great too, does the battery ever hit you seat post when the swing arm moves? How fast and for how long?
Really considering making a "frankenstien-bike" for a commuter to work!
good job man!

[rptarqui]

I initially thought about hose clamps, but was worried about it digging into the carbon. I bought some rubber squares to protect the frame, then thought the fabric would work, now I think if would tend to loosen over time. Thanks for the suggestion. I've been rethinking the rear rack as well, as I don't like the weight back there and kind of rough on the battery. I like your on fame solution. Good idea about the epoxy.

[TaylorN]

@taylorn.. thanks. The motor is a cyc x1 pro gen2. I got it from electrifybike.com, cycmotor.com also sells directly. Here is the link for electrifybike. I dealt with Mark, who was very helpful with problems I encountered. https://www.electrifybike.com/store/...e_Motor.html#/

I did look at the BBSHD, however I was concerned about the loss of ground clearance, and size of unit. The X1 pro I feel had a better design for my bike. It is smaller, more powerful, and more expensive. The Demo8 has a 83mm bottom bracket, so right at the max size, without going to a fat bike sized crank and adapters. I actually had to trim off the tabs/ears on the PF30 adapters to be able to thread the retaining nuts onto the axle. This gave me space to use a 1mm spacer on the non-drive side, to move the mounting bracket away from the rear linkage arm. I imagine a narrower BB will avoid the problems I encountered, as you would use spacers on the BB. The chainline is pretty much the same with the motor as my regular cranks. I have no problem shifting through all gears. The Demo8 is a downhill bike and already pretty heavy, so I wasn't too worried about the added weight. The shark battery is 7 lbs, not sure about the motor, The bikes probably around 50 lbs. The motor locks onto the bottom bracket via the BB cups, and it has a brace that mounts inside the frame to keep it from rotating. On this frame the brace wasn't long enough, so I used heavy cargo strapping to secure it. It feels pretty solid, but time will tell.

That's awesome! thanks for the detail and the photos.

I just got done converting a 2010 Banshee Legend for a friend. Purchased BBSHD from electrifybike.com and 8ah battery from bicyclemotorworks.com. Made a 3d printed shell for the battery. The height to the bottom of the motor from the ground is 10.5" (but had to make a non-structurally-compromising notch in the frame so the motor would rotate to that height). 10.5" is not bad, but the clearance you have with the X1 seems best case scenario!

Oh, and I don't know if you need it, but a tip for builds is to use stainless steel hose clamps to hold the motor instead of fabric straps. also, epoxy putty is a cheap and awesome way to build up transitions from flat to round surfaces, etc. if you don't want it to be a permanent piece, you can use clear packing tape as a release agent on your frame so the epoxy can be freed after it cures. I use it everywhere in life now ;)

[rptarqui]

@taylorn.. thanks. The motor is a cyc x1 pro gen2. I got it from electrifybike.com, cycmotor.com also sells directly. Here is the link for electrifybike. I dealt with Mark, who was very helpful with problems I encountered. https://www.electrifybike.com/store/...e_Motor.html#/

I did look at the BBSHD, however I was concerned about the loss of ground clearance, and size of unit. The X1 pro I feel had a better design for my bike. It is smaller, more powerful, and more expensive. The Demo8 has a 83mm bottom bracket, so right at the max size, without going to a fat bike sized crank and adapters. I actually had to trim off the tabs/ears on the PF30 adapters to be able to thread the retaining nuts onto the axle. This gave me space to use a 1mm spacer on the non-drive side, to move the mounting bracket away from the rear linkage arm. I imagine a narrower BB will avoid the problems I encountered, as you would use spacers on the BB. The chainline is pretty much the same with the motor as my regular cranks. I have no problem shifting through all gears. The Demo8 is a downhill bike and already pretty heavy, so I wasn't too worried about the added weight. The shark battery is 7 lbs, not sure about the motor, The bikes probably around 50 lbs. The motor locks onto the bottom bracket via the BB cups, and it has a brace that mounts inside the frame to keep it from rotating. On this frame the brace wasn't long enough, so I used heavy cargo strapping to secure it. It feels pretty solid, but time will tell.

[TaylorN]

Put a X1 Pro on my 2015 Demo8. Still working out the cabling. Not sure I can use the brake cut off sensors with my brakes. Hoping the battery rack works out..

Nice setup! Do you have more details on the X1? Where did you get it from, how much $$, what size bottom bracket do you have, what does it weigh, have you installed a Bafang motor before if so how does it compare, what is your overall height from the ground to the bottom of the lowest part of the motor/bracket, why X1 over BBSHD, is it rock stable when installed, how is the chainline, can you provide lots more detailed photos?

Thanks! :)

[rptarqui]

Put a X1 Pro on my 2015 Demo8. Still working out the cabling. Not sure I can use the brake cut off sensors with my brakes. Hoping the battery rack works out..

[rptarqui]

Appreciate the feedback. I'm concerned about the motor hanging low as well, though probably not really a problem for my local trails. The US National parks are opening up to e-bike use, so more incentive to give this a try. May take your advice an get two mini's. Thanks again.

[Stewinnz]

Rich

Its a 2015. The bottom bracket used in these is larger than that required of the BBSHD so you need an adapter. Your bike probably has an adapter already in there, just pull out the crank and measure the diameter of the hole to see if it matches the BBSHD.
This bike has been good but it really depends on what you will use it for, I would have liked to use it on grade 5 tracks but the motor hangs too low and hits the ground so I have to be careful which tracks i can ride.
If I was to do the build again I would use a GT force i drive as the clearance is a lot better.
Backpack battery is ok, i would run a smaller battery though, the mighty mini would be good, get two for if you want to do longer rides.

Stew

[rptarqui]

Hey Stewinnz,

What year is your Demo8? I'm thinking about doing the same with my 2015 Demo8. I'm a bit confused about the BB. I thought the BBSHD replaced the entire bottom bracket. Looks like you were able to use a eccentric BB shell with the motor. How do you like running the battery in the backpack? Any tips you can share with this frame?

Thanks,
Rich

[TaylorN]

Nice! Thanks for sharing Dee!

3mph loss is not bad. At 33mph I personally don't want to be going much faster without 4 wheels anyways ;)

Keep us posted on the battery stats you had before and after.

[Dee]

TaylorN,

Our conversation got me thinking about that 30t.

So I bought one and slapped it on. I liked it a lot!

Chain didn't fall off once during the initial run. It did fall off the 36t frequently enough that I decided to end that with the DIY chain guide.

Lost about 3mph off the top end so the max I got out of it was 33mph. Not too bad really.

Thanks for giving me the 30t bug!

Edit: This thing is zippy! And I didn't change the cogset at all. So, with a 32t granny gear it's less than a 1:1 ratio. Had no problem hitting the top of that hill without pedaling. Battery stats show a definite improvement on miles per volt with the 30t.

[Dee]

You will have a hill climbing monster! Let me know how that works out on the top end on a flat. I might have to buy a 30t just to see how zippy it is with that much torque.

[TaylorN]

Yeah, I don't really care about the top end very much since its not a commuter. This is strictly to go up the steepest hills using the least amount of battery and then ride back down. The 30t Chainring in the 11t rear sprocket seems to be plenty fast for me. If I need a little more speed when pedaling I will just give it some throttle :)

[Dee]

Thanks TaylorN!

Not sure whether or not the offset is the same. Seems like it should be.

I chose the 36t because I was worried I'd lose too much on the top end if I used the 30t.

Using the 36t it's a pretty good hill climber but the 30t, if you were doing a lot of that would be the better choice.

If I lived in San Francisco, I'd want the 30t for instance. I still pedal up the steepest hills but none of the regular roads up into the mountains forces me to pedal. I can usually just power up it in first gear, and sometimes 2nd gear depending upon the grade.

So it was an attempt at keeping most of the top end, while still having a serious granny gear.

I hit 35mph in fourth gear yesterday, that's the 12 tooth cog, with 48 volts in the battery so like 45% full or so.

[TaylorN]

Thank you for the details and excellent photos Dee!

why did you end up going with the 36t chainring instead of the 30t luna might mini chainring? They have the same offset, right?