Electra Straight 8 build and Ebike conversion

[zdoor]

I’m new to the forum and going to try my first build thread.

I’m starting with an Electra Straight 8 I’ve had since 2017. Originally bought to cruise around Long Beach when I was in LA for work. It was perfect on the beach, super comfortable and a style I always liked.

Fast forward to now and while I still liked the bike, it wasn’t well suited to the hilly area I live and I was starting to have issues with the coaster brake not engaging. Did a little research and discovered the hub was under recall for the brake issue which was very common. SRAM actually did this right and gave full blue book value for the bike. So I decided to take what I got and start rebuilding my old ride into an Ebike. At least I can offset some cost and fix the issue at the same time.

Did a ton of research and read every thread I could find on straight 8s and Straight 8 Ebike projects. The bike isn’t a great conversion candidate as it lacks some components that aren't easily Added. But I love the bike and the challenge is appealing.

I’m pretty mechanical by nature and pretty good at problem solving. My other hobby and small hobby business, is restoring, building parts for and tricking out pinball machines. So, creating parts and electronics aren’t too intimidating and I love doing that kind of stuff.

Biggest issue the bike has is brakes. From the factory my year only included the rear coaster brake which was recalled. As part of the recall I had to send in the defective rear hub, so the back end needed to be reinvented anyway.

After researching I decided to go with a rear hub motor. The one I liked the best and am going with is the GMAC geared motor from Grin technologies. It had the best combo of power and features I wanted. I also liked their ability to customize and pick and choose the entire setup, rather than going with a prefabbed kit that has to cover a bunch of variables. One of the coolest things this motor has is regenerative braking that can be setup on a variable application so the braking force can be increased or decreased similar to a conventional brake. I’ll post more about it when I get to that part of the build for anyone that’s interested.

While regen is cool it doesn’t solve my initial problem of adequate brakes. So, a small project got bigger. A theme I’ve figured out is pretty normal here lol

Heres a couple before pics… quality sucks but didn’t realize I was going to do a build thread when I took Em…

 

[zdoor]

I knew I wanted to add a disc brake but my front end isn’t designed for It. so… A new front end was a must lol

Rebuilt the front wheel with a Shimano Hub, black anodized spokes and a 160mm rotor. Reworking the forks seemed dumb and I thought a springer would be cool and improve the ride at the same time. Went with the Sunlite deluxe springer. It fits the long neck of the bike, solves the brake caliper mount issue and looks awesome. decided on a Shimano hydraulic brake in black.

Now just need the steering tube hardware to arrive. Damn UPS is slow….

 

[zdoor]

Couple pics of stripped down frame. I’ve got fish lines run inside the down tube through the slots originally used by the factory for cabling. Since the new back end hub motor will be a single speed, I’m Reusing the channel to run my electronic wiring. after years of doing pinballs many of which went to shows, I cant stand messy wire runs…

 

[zdoor]

Waiting on parts to arrive so did a little work on the cargo rack. Still looking for a rear brake light that has a nice look to add to the ... end

 

[Couch tater]

Cool project! I'm with you on messy wiring, gets my dander up (unless it's a full on rat, then messy wiring makes the build even better).

Helpful hint here for uploading photos: when inserting them click on "Full image". I think you can edit your posts to do it after the fact.

 

[zdoor]

Thanks! Think I figured the pic thing out

 

[Karate Chicken Industries]

Once you get to riding, keep a close eye on the rotor side flange of your front hub. Radial lacing often renders hub warranties invalid due to flange failure being a common side-efect of that type of wheel build.

 

[zdoor]

Thanks for the heads up! Bought the hub, rotor and spokes locally from my local bike shop and went with their recommendation. I’ll keep an eye on it.

 

[zdoor]

Got lucky and UPS delivered my forks last night. Im going to disassemble them and paint them in a matte finish to match the finish already on the frame.

Going to have a little “MacGyvering” to do. one of the many unique obstacles on this bike is the length of the head tube on the frame. At 9.5” it’s longer than most by a good 3”.

 

[zdoor]

The steering tube length at 300mm on the main part of the fork is plenty long enough. But the bracket, threaded rods and springs on the forward fork are designed for a shorter length. There is some adjustment ability in the linkage but it’s not close to enough to accommodate the steer tube length on this frame.

Going to see what I can come up with to get to the length I need which is 2 3/8” (60 mm) longer than what the bracket and threaded rods on the front assembly will accommodate. Any ideas would be helpful. Cant find many examples of installs online I can steal another idea from.

 

[MattiThundrrr]

Paging the resident suspension expert. He's been building some sick springers lately. Dr Wildcat to the operating room please!

 

[Wildcat]

Bolt extensions?

 

[zdoor]

I ordered a coupler and hex socket head in polished chrome. Will see how that does once they get here. Wasn’t easy to find. It’s a 10mm thread with 1.25 pitch (fine thread).

 

[zdoor]

Made some progress. Decided to powder the forks to match the bike and of course that led to making another change. Couldn't resist changing the bike color. Ended up picking a Charcoal matte gray I liked a little better than the matte black.

Anyway, started assembling some things today. Got the battery location figured out. Battery is a 52V 20A . Used the grin Bob mounts. It feels pretty solid.

 

[zdoor]

Torque sensor is installed. Will wait to put the chainring and cranks on until I’m closer to finished

 

[zdoor]

And heres the new Sunlite Deluxe Springer. Powdered it to match and had to get my MacGyver on to get the suspension to accommodate the length of the head tube. heres What I came up with. Also replaced bearings and redid the headset. The bracket is for the Ebike screen

 

[zdoor]

Got front brakes installed. First time with hydraulic brakes. They came prefilled. Install was easy. Only issue I have is at some point I want to route the brake line through the cable management built into the fork. I think to do that I have to cut the end of the line, route the line, reinstall a new end, olive, etc… and bleed the line. At least that’s what looks like has to be done to get the end off and route the line. Don’t have any of those items or tools. So just tidying things in place with a zip tie for now. Any other ideas are appreciated.

 

[zdoor]

Got the two main wire bundles routed through the frame. Wasn’t too bad. Had to cut the main wire bundle to get it in the frame. Fortunately years of restoring and repairing pinball machines made this pretty familiar. wiring is pretty basic and the bundles are nicely color coded. So a little solder work and shrink tube and connection is good as new. Came out great and main wire run from Cycle Analyst monitor at handlebars to controller and battery at frame mount is done.

Now I wait for the geared hub motor to come in. hoping next 10 days or so. Going to work on the handlebar wiring and see how tidy I can get that. Also have a headlight to install at stem on order that’s not arrived yet.

 

[zdoor]

Still waiting on the GMAC hub motor. They are now back ordered until early November. Hopefully they don’t get pushed back again.

In the meantime I’ve been trying to wrap up other items so the bike is mostly ready to go once I get the hub motor.

Worked on more wire routing today. Getting closer. Have two main control wires running inside the down tube to the controller. My solderEd connections are neatly shrink tubed and protected Inside the frame tube. The exposed portions are sheathed and run to the cycle analyst display.

The rest of the wiring on the handlebars(throttle, ebrakes, menu switch and headlight) that run to the Cycle Analyst display is still in process.

 

[zdoor]

Ended up giving my son the headlight I originally ordered. It’s nice and bright as ..... But it’s ridiculously small. would've returned it if he didn’t want it…

I mean I have big hands. But, seriously? This is the Lezyne Macro 1000. Ended up ordering a Rad Power premium light. It’s closer to what I was originally thinking and about the right size…