Electra Straight 8 build

zdoor

10 mW
Joined
Aug 31, 2022
Messages
32
Currently own a 2015 Electra Straight 8 that came with the SRAM i motion 3 rear hub that has been recalled.

Been researching Ebikes and was originally planning to replace my existing beach cruiser with a new Ebike. But now I’m leaning toward converting my Straight 8 as I love the look of the bike and it’s really comfortable to ride. I’m pretty mechanical and have always worked on my own bikes and motorcycles. So I think it’s a project I should be able to handle with some research and patience…

After looking at different conversion options I’m thinking of using the Bafang BBS02 mid drive as the motor. I haven’t decided on the battery yet. But I’d like to mount it in frame and love some of the custom work I’ve seen here and online. Really liked the leather bag used on one Straight 8 posted here. My bike also need the SRAM imotion 3 hub replaced due to the recall. So thought I might be able to kill two birds with one stone by incorporating a new internal gear hub that also integrated a drum brake. I’ve looked at other builds of straight 8s online that added rear disc brakes and welded caliper mounts. But, welding isn’t in my wheelhouse (I’d need to outsource it) and I’m thinking a drum brake in a new hub which I’m replacing regardless would be a pretty decent alternative for the rear… Has anyone gone that route and any thoughts/feedback on hub alternatives for the SRAM hub I need to replace? Good/bad experiences? Anyone able to relace the new hub into the existing wheel?

For the front, I’m looking at options to replace forks and add disc brakes. I’ve called Electra and can purchase the new 2022 Straight 8 front forks from them which now incorporate mounts for front calipers. I’m also not opposed to aftermarket forks or forks that add suspension. I’m mainly looking to address the brakes but might as well look at other options to improve the bike while I’m at it…

Any feedback on my plans is greatly appreciated. I’ll document the build here once I start.
 

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So did a bunch of research and read every thread I could find on Electra 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 part of the recalled SRAM imotion 3 hub. 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. That was the biggest thing in choosing this hub.

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
 
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

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 hydraulic disc brake for the front.

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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…CC712CDB-2B0D-4B85-9539-D23174726F64.jpeg2641A45C-91A4-4A81-BDF2-6B3CAF0AD38E.jpegCEFCACC8-4184-4B99-B298-4437F1A9D219.jpeg
 
The steering tube length at 300mm on the main part of the new 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. 0E767B49-7A27-4363-9D65-69B1A20AC49C.jpeg26367B5C-C147-4417-93FC-53DF41D28941.jpegDC96BB9D-95C0-4F4B-BD09-A24FAA267B5D.jpegE3E1ADC6-34CE-4164-94F8-D36FE0B59D03.jpeg
 
Made some more 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 the Straight 8 came with. Also liked the idea of going black/grey to make something different. I think I’ll be happy with the new look…

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.7219705C-E835-4947-BE68-8AAA8490E55B.jpeg16C7A0F2-A3B6-47CE-B1B9-79C23376FB07.jpeg9495280D-95A7-488C-87F0-1A65AEC51184.jpegB14E9FE4-ED41-483A-88DF-54C63CD71639.jpeg
 

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Torque sensor is installed. Choose to go with the erider torque sensor instead of a basic PAS system. Just seemed like it would fit my riding style a little better…

Will wait to put the chainring and cranks on until I’m closer to finished
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And heres the new Sunlite Deluxe Springer. Powdered to match and had to get my MacGyver on to get the suspension to accommodate the length of the head tube. Here’s what I came up with.

Also replaced bearings and redid the headset. The bracket is for the Cycle Analyst screen…77F08885-EC49-45DF-9480-61376A903B77.jpegAF5768E4-F990-4722-94CA-B1074C5CE97D.jpegE004B5BE-E68A-4A3F-9E48-6CE912A5F616.jpeg1296AFC8-8F37-4DD6-812A-C522F7FBD7E1.jpegAFBEE796-1F45-43CF-ADD8-1CB7F82286DD.jpeg266F8723-D6D5-4886-A9F6-61E4B2A1AD93.jpeg
 
Got front brakes installed. First time with bike hydraulic brakes. Was pretty easy. They came prefilled and install is pretty straightforward. No instructions but not hard to figure out…

Couldn’t route the brake hose through the forks built in cable guide. Will need to cut the brake hose end then install a new end, olive and bleed the line. Unfortunately I don’t have any of the tools or parts to do that so zip tied for now and will come back to it later. Any other ideas are appreciate.2ECEF6D9-330D-4895-BA5E-3CF56DDE2BDF.jpeg3FA0CE33-ADA4-4F19-8E4F-41D1414BC61F.jpeg0B36467E-82DD-4FD4-A8A7-262D66056D56.jpeg
 
Got the two main wire bundles routed through the frame. Wasn’t too bad. Had to cut the main wire bundle to get it through the frame. Fortunately. Years of restoring pinball machines made this pretty familiar.The wiring is pretty basic and color coded. So, a little solder work, shrink tube and good as new… came out great and main wire run from Cycle analyst to baserunner controller in the battery cradle is done.

Now I wait for the GMAC motor to come in. Going to work on the handlebar wiring and figure out a headlight while I wait. Want to get the wiring as tidy as I can…FC7524CA-E191-421D-A6F6-9269E3664652.jpeg
 
Got more done on wire routing. Have everything organized and sheathed. Cant stand messy wiring. So taking my time on it and doing it right. Have a ton of time anyway. GMAC isn’t expected until November…. :(

Also ordered a Rad Power bikes premium headlight. I think it will fit the look of the bike well.ECF9C9AE-EE34-4A7D-BE2C-97ECDF6FD510.jpeg220D5714-4872-4894-92F5-DCFD95D2E455.jpeg173E1085-5B4A-45A5-8317-C8016EABCCC7.jpeg
 
zdoor said:
Couldn’t route the brake hose through the forks built in cable guide. Will need to cut the brake hose end then install a new end, olive and bleed the line. Unfortunately I don’t have any of the tools or parts to do that so zip tied for now and will come back to it later. Any other ideas are appreciate.
Try XOD website (should also have bleeding instructions) or ebay. Ytube might have helpful video.

What is the springer fork travel?

Nice ultra-clean build. :thumb:
 
Bike is looking nice.

If you don't like the look of the hose clamps holding the battery, Rivnuts will work fine and you can place them anywhere you want.

https://www.amazon.com/WETOLS-Rivet-Metric-Mandrels-Rivnuts/dp/B081GDRTXP/ref=sr_1_3?gclid=Cj0KCQjwhsmaBhCvARIsAIbEbH6spZl_Rn2iJ7QKHWX7koiPpauSgvfW4aQFRLj80kGz9RMh2aKxdQcaAlxCEALw_wcB&hvadid=410027268373&hvdev=c&hvlocphy=9031738&hvnetw=g&hvqmt=e&hvrand=17117498831971326112&hvtargid=kwd-898488844&hydadcr=7433_11109607&keywords=rivnut&qid=1666393148&qu=eyJxc2MiOiI1LjMzIiwicXNhIjoiNS4yNCIsInFzcCI6IjQuOTgifQ%3D%3D&sr=8-3

I used SyrVet silicone bandage to cover up the wires on my Townie. They come in lots of different colors. Pics are in my signature below. They can be found in 1" widths too.

https://www.allvetsupply.com/syrflex-cohesive-bandage.html?gclid=Cj0KCQjwhsmaBhCvARIsAIbEbH64XnI1tl2bonJ8X1-CqQFLk_kdiTsXTjWOIuYWCChK1rxQrM1JHEEaAkd1EALw_wcB

Rear tabs for disc brakes are simple to add and shouldn't cost much to get welded on to your frame. I used the tabs that came with my Avid brakes. However any welding will mess up your fresh paint job.

Grin makes a nice tail/brake light too.
 
nicobie said:
Bike is looking nice.

If you don't like the look of the hose clamps holding the battery, Rivnuts will work fine and you can place them anywhere you want.

https://www.amazon.com/dp/B081GDRTXP
I purchased a rivnut tool last November. The following is my Amazon Review along with some inks I could not put in the review on Amazon:
====================
https://www.amazon.com/dp/B08J82QPVC
PROSTORMER rivet setter tool review:

As far as I can determine there are six of these curved handle 3in1 rivet set tools sold on Amazon. They range in price from $38 to $57. As far as I can tell from the enlarged photographs, the biggest difference is that some vendors used a professional photographer and some used an amateur photographer. They even use the same molds for the 'soft rubber handles'. They all also fail to properly translate the word "nibbler" (for some unknown reason they use the word "reamer"). The handles are 7-1/2 inches long from the pivot screws to the ends. Unlike some tools the spring loaded handles open and close in a symmetric manner.

I purchased this to use with the longer (stronger/higher quality) 'Plus Nuts' inserts. The 'Proper' tool to use for 'PlusNuts' is the Astro Pneumatic 1450 that is equipped with longer mandrels for those inserts. However it costs nearly three times as much and can only be used as a rivet nut setter. To be fair, it also comes with a wider range of mandrels including larger sizes.

The 1/4-20 mandrel on this tool only extends a maximum of 5/8 of and inch. One inch is needed for the PlusNuts. The trick to using the PROSTORMER tool with 'PlusNuts' is to replace the screw with a longer screw and a flat washer. I was able to order six 1/4-20x5 inch grade 8 Hex head cap screws for $11. I used JB weld to add a short piece (two inches) of 3/8 OD by 1/4 ID tube to the top section of the bolt (just to center it in PROSTORMER tool).

One star deducted because of the overly short mandrels.

===REFERENCE========================================================

ATMOVL
https://www.amazon.com/dp/B0895GGS6T
$53.99

AMTOUTLET
https://www.amazon.com/dp/B094MYVWJ4
$44.99

Eastvolt
https://www.amazon.com/dp/B08K9P7FPP
$56.36

J H Metal
https://www.amazon.com/dp/B08PY91ZFV
$45.99

PROSTORMER
https://www.amazon.com/dp/B08J82QPVC
$41.99 (10% discount = $37.791)
Mandrels for Rivet Nut Setter come with with 6 Metric & SAE Mandrels (M5, M6, M8, 10-24, 1/4-20, 5/8-16).

SAKER
https://www.amazon.com/dp/B094MYVWJ4
$44.99
Better photographer, much nicer case
(Also sold under the brand name Tacklife)

Plus Nut
https://www.amazon.com/dp/B09GXQ26V2
1/4-20 by 1 inch steel insert

Astro Pneumatic 1450
https://www.amazon.com/dp/B01JBNNJ3Q
$99.74
Includes 9 SAE and Metric sizes: 10-32, 10-24, 1/4-20, 5/16-18, 3/8-16, M5, M6, M8 & M10

Cardinal Rivnut Tool
https://www.amazon.com/dp/B07DP3W4WY
$87.40
exspensive ...

===========================================================
RIVET NUT USA
Tools: https://www.rivetnutusa.com/install-tools-rivnut-rivet-nut/
PlusNuts: https://www.rivetnutusa.com/plusnut-rivet-nut-rivnut/
Amazon: https://www.amazon.com/s?me=A1LPP0L3P8PZ7I&marketplaceID=ATVPDKIKX0DER
 
Thanks for the input. I like the Rivnuts look. Going to play with the position for a bit using the hose clamps. Have a couple inches of play in both directions right now and want to see if moving the battery an inch or two in either direction affects the balance.

The wrap looks like an interesting idea. The wire exit out of the baserunner is fixed on the same side as the chainring. So clearance there is only about 1/4”. Might be a little paranoid but want to make sure I have it nice and tight there so it can’t move toward the chainring. That might be a better looking option than heavy duty zip ties…

I thought about the rear disc caliper mount. But after exchanging emails with Grin tech support I decided to try using the variable regen on its own lever for the rear brake and hydraulic disc on the front wheel. If it doesn’t feel adequate than I’d go down the bracket route. Welding isn’t my forte. So I’d have to farm that out.
 
RE: Rivnut tool

For installing rivnuts to the downtube (or really any tube on the bike frame) a rivnut tool is not necessary, or (in the case of working inside the triangle with space constraints) preferable.

I have successfully installed several using an appropriately sized allen-head screw, nut, and some washers. You can find tutorials on the Ytube.

Helpful tips:

Do not drill the hole too big. Interference fit is best (have to tap in the rivnut w/ a small hammer).

Use good quality rivnuts. M5, or for larger tubes, M6.

Three is good to hold the average battery.
 
Working on tying things up while I wait for the hub motor. Got the headlight and taillight installed. The Rad bikes headlight fits nicely and looks good, Its not that bright but got it more to be seen than night riding. Just about done with the wiring at the handlebars. Just need the switch I bought for the lights. But looking pretty good.

Need to finish the last bit of wiring under the bike and trying to figure out if I’m going to need an extension on the motor cable. I think I’m 4-5 inches short
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I am particularly interested in how the springer fork works out for you at E-bike speeds (20 MPH or greater).
Not casting doubts ... just curious.
One advantage to those is that one could fabricate new bottom links to vary the rake/trail of the front wheel.
(yes ... I know that might also require doing something about the caliper mount as well)
 
Found the motor cable measurement on the GMAC hub online. I’m going to be about 5.5” (139mm) short reaching the L1019 connection from the base runner. Irritating… going to have to make an extension or elongate the end coming from the controller… :(
 
What kind of tape do you use on the ends of the braided wire sheathing?
 
99t4 said:
What kind of tape do you use on the ends of the braided wire sheathing?

Used electrical tape. Bent the ends over themselves where the sheath terminates to make a slight ridge and wrapped one revolution. Then doubled it up with a second piece without bending it over to make a cleaner look and finish it up. Probably a waste of time but since I’m waiting on the hub motor to arrive at Grin, I have tons of time…

Figures the last piece I’m waiting for is the hub motor. I’ve been dreading lacing that motor in and truing the rim. Par for the course it would be one of the last things I’ll have left. Lol
 
Reworking springers. Have a friend who is a machinist that was able to custom cut some aluminum spacers and we reworked the spacers. I think it looks much better and closer to a “factory custom” type look. Going to powder the raw aluminum to match the rest of the bike. Was thinking of going black but I think matching the frame and fork color will be a nice clean look. Here’s the raw reworked springer before powder. Travel is smoother also.1BB8004D-77AC-4886-A9BD-4EBD272BDC6F.jpeg39335CD3-3B8F-41A5-BFED-5F0CB8AFC077.jpeg
 
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