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Grin Giant: Another 1st post thread

yoink

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Joined
May 31, 2023
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Location
Saint John, NB
(I originally posted this on the electricbikereview forum. This one has some added info.)

I've built lots of bikes over the years, but this was my first DIY e-bike build.

Origin bike: Giant ATX 870 '97 (the first bike I bought for myself).

Origin story: I'd been using this bike as my winter commuter while in Montréal. It came with me out east when we moved here. After an LBS failed to let me know that an e-bike I'd had on order (with a supposed "we can absolutely get this for you") wasn't going to be available, my partner suggested I look into repurposing this old thing. I'm glad she did.

I found Grin via random places online and decided that I liked the kool aid they were selling, in addition to being fellow Cannucks.

Oddly, the biggest challenge of the whole build was finding new chain rings for the 94/56 BCD triple crankset I've had on it since '98. In particular, the 46t large ring is NOS from a brand called "Summit" which looks almost EXACTLY like the original Race Face Ramped Race Ring from the late 90s with the exception being that it doesn't have the black powder coating. It was made in BC (also like the original, mid/late-90s Race Face alloy rings).

Lots of parts from "out west" on this old dog.

image.jpeg

Build basics:
- GMAC 8T
- Phaserunner V6
- 52V 23Ah battery
- Continental Urban Contact E50 tires. These were shockingly hard to find in 26" 2.0 and 2.2 sizes.
- Everything else is more or less stock (I've gone through a few RDs in my day though)

I designed and printed some custom parts including the fairing behind the Phaserunner to hide all the bulk of the cabling.

I also used a short 3.5mm TRRS extension to improve ease of access when connecting to the Phaserunner for adjustments. Getting the 3.5mm TRRS USB cable in and out of the Phaserunner once everything was wired up was, shall we say, unpleasant. Now the 3.5mm Phaserunner input is just at the bottom of the fairing.

I made an out-front mount for the CA3 because I didn't like the off-the shelf options. It was 3D printed in PAHT-CF so that it would be both durable and not melt in the hot sun during the summer (a real problem with PLA parts).

The current design is made to fit perfectly around my stem, and so it might not work on other setups without some changes, however, I'd be more than happy to clean up the model and put the Fusion 360 file on Printables. The 3MF files are already there for the brave: Printables

It took a few iterations to get it here, but I'm really pleased with how it turned out.

image.jpegimage.jpeg

Finally, I designed and printed a small mount so I could use the throttle (for controlling regen braking) without it interfering with my old XT trigger shifter. The one downside to this DIY e-bike project was just how many extraneous controls/cables there are to manage (especially compared to my partner's off-the-shef Liv e-bike).

I'll probably ditch the throttle altogether as I've found little use in modulating regen and I don't use the bike without pedalling. Happy to share this model too if anyone wants it. I can't imagine I'm the only one who found some of the controls getting in the way of core drivetrain functions. This mount would also work for the CA3 digital controls.

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I've been riding it for a month and while I'm having some minor issues (minor I hope), it's been a pretty great grocery-getter and a fun way to keep this bike alive.

I don't love the Triangle battery, mostly because installing and removing it is a real pain in the butt. Also, the high centre of gravity it creates, while fine when riding, has resulted in a number of tip-overs, including an entire bike rack that fell over with it. At the same time , the battery and its placement actually helped keep everything (cables, parts, etc.) in a pretty tidy configuration for the build. So strikes and gutters, as usual. ;)

Originally I thought about getting a frame bag to hide everything, but looking it at it now, I can't see why I would bother.
 
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Nice looking e-ebike, diy is cool man, making and building things is cool dude!
 
I don't love the Triangle battery, mostly because installing and removing it is a real pain in the butt. Also, the high centre of gravity it creates, while fine when riding, has resulted in a number of tip-overs, including an entire bike rack that fell over with it.
Have you tried a better kickstand? One of the double arm ones?
 
I also used a short 3.5mm TRRS extension to improve ease of access when connecting to the Phaserunner for adjustments. Getting the 3.5mm TRRS USB cable in and out of the Phaserunner once everything was wired up was, shall we say, unpleasant. Now the 3.5mm Phaserunner input is just at the bottom of the fairing.
Oh my goodness, what a good idea. I *hate* trying to wiggle into that damn port. Did you find a particularly short one, or just wind up the excess on a, what, 3ft cord?
I'll probably ditch the throttle altogether as I've found little use in modulating regen
Grab the latest CA firmware and you can control regen by back pedaling, which is pretty novel and might suit you better.
 
What brake pads are you using ? Kool-stop has wet weather pink normal black and a combo with both colors they work extremely well and last a good amount of time
Yeah there's a lot of bikes nowadays where they have the battery fitted to the frame extremely well but your motor is a better option in choice than they have. As far as I know.
 
It’s a good mix of parts, all quality, and I like seeing old frames in great condition. Plus, every bike should have at least one silly thing, which you have covered with that crankset.

Curious about the fork. It looks decent. What is it?
 
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