OkinawaJapan
Established
- Joined
- Jun 17, 2012
- Messages
- 57
Hey guys.
I've found a nice DD hub motor I am going to order to try out. Seems like a good alternative to the Grin Max45 I have on order for my main bike.
This is the only other FAT DD motor I've ever seen as yet. Anyone else found any? This looks promising for only $150 delivered!
Going to build this for my backup bike Build #2. My bike's got 20x4.0 inch, 82mm wide wheels on it. So I'm looking for a rim to order online to match that.
Seems that Grin doesn't sell an 80mm wide 20 inch fat rim sadly. Trying to understand if 36H is fine or is it best to stick with a 32H rim?
If so, I'll need a source link for quality 20x4.0 80mm wide, 32H rims please. Not finding anything.
I plan to order my spokes from Grin. Sapim Strong 13-14g Butted Spoke, Black
ebikes.ca
So far I can figure out a few of the dimensions:

Flange Diam. = 179mm
Flange Spacing = 66.5mm
Dishing Offset = -3mm? See below.
# of spokes = 36. I'm only finding 20x4.0 fat rims on aliexpress that are 36H. Not finding 32H rims yet. Maybe 36 will be stronger anyway?
Grin uses 32H but are sold out currently. They don't have 80mm wide rims at all either.
Axle Length 175mm
Rim Settings:
Again, I have only found these aliexpress basic rims so far. If you've got links to quality 20x4.0 80mm wide rims I'll graciously accept them.
Don't have this info yet as it's not posted in the listing. I might have to get the rim in hand first to measure it.
https://vi.aliexpress.com/item/1005006422216871.html $33.28 with free shipping.
or here: https://vi.aliexpress.com/item/1005005192914786.html $30.70 with free shipping.
View attachment 1755347792506.webp
Lacing options:
Will do a single cross as per Grin's recommendation in their video for ebike hubs.
ERD = ??? I've asked the resellers. Awaiting response.
Left Offset = 1.75 ??? I've asked the resellers. First reseller said, "The left and right offset is 1.75-2.125"
That sound usable? How do I input it? So far I input it respectively as listed.
Right Offset = 2.125 ??? I've asked both resellers.
Rim Width = 80mm (My rims measure 82mm exactly outside width with a caliper.
I'm following Grin's video on how to measure a hub motor's "Lock Nut Dimensions" but I can't get the axle hub width from the below diagram as I don't think it's
listed. Might need the hub in hand as well to determine?
Actually I may have figured it out. I think it's 28.5 - 31.5 = -3mm for the offset?
Shown here at 03:20 in the video:
Here are the specs on the DD rear hub motor: Motors for Electric Bikes: New QS159.8 E Bike Hub Motor
I'm asking the factory to install an L1019 connector and NTC 10k thermistor with a beta value of 3450 before shipment. I will pair this with a Baserunner L10 and will run dual V7 torque arms on it for regen.
This is what I get so far:

Or I could put the left elbows "In" for a better tension ratio. I'm leaning toward this for balance and I can order all 115mm length spokes.

Interested in all the feedback I can get. Thank you.
I've found a nice DD hub motor I am going to order to try out. Seems like a good alternative to the Grin Max45 I have on order for my main bike.
This is the only other FAT DD motor I've ever seen as yet. Anyone else found any? This looks promising for only $150 delivered!
Going to build this for my backup bike Build #2. My bike's got 20x4.0 inch, 82mm wide wheels on it. So I'm looking for a rim to order online to match that.
Seems that Grin doesn't sell an 80mm wide 20 inch fat rim sadly. Trying to understand if 36H is fine or is it best to stick with a 32H rim?
If so, I'll need a source link for quality 20x4.0 80mm wide, 32H rims please. Not finding anything.
I plan to order my spokes from Grin. Sapim Strong 13-14g Butted Spoke, Black
Here's what I've input into the spoke calculator so far based on the below specs I've found:Online Spoke Calculator for Hubmotors and Ebikes
Our handy spoke length calculator allows for easy calculation of spoke length for custom builds - and is the only one of its kind to include paired spoke holes in the flange as is common with many large diameter hub motors. It also creates an automatic side view drawing of the laced wheel and...
So far I can figure out a few of the dimensions:

Flange Diam. = 179mm
Flange Spacing = 66.5mm
Dishing Offset = -3mm? See below.
# of spokes = 36. I'm only finding 20x4.0 fat rims on aliexpress that are 36H. Not finding 32H rims yet. Maybe 36 will be stronger anyway?
Grin uses 32H but are sold out currently. They don't have 80mm wide rims at all either.
Axle Length 175mm
Rim Settings:
Again, I have only found these aliexpress basic rims so far. If you've got links to quality 20x4.0 80mm wide rims I'll graciously accept them.
Don't have this info yet as it's not posted in the listing. I might have to get the rim in hand first to measure it.
https://vi.aliexpress.com/item/1005006422216871.html $33.28 with free shipping.
or here: https://vi.aliexpress.com/item/1005005192914786.html $30.70 with free shipping.
View attachment 1755347792506.webp
Lacing options:
Will do a single cross as per Grin's recommendation in their video for ebike hubs.
ERD = ??? I've asked the resellers. Awaiting response.
Left Offset = 1.75 ??? I've asked the resellers. First reseller said, "The left and right offset is 1.75-2.125"
That sound usable? How do I input it? So far I input it respectively as listed.
Right Offset = 2.125 ??? I've asked both resellers.
Rim Width = 80mm (My rims measure 82mm exactly outside width with a caliper.
I'm following Grin's video on how to measure a hub motor's "Lock Nut Dimensions" but I can't get the axle hub width from the below diagram as I don't think it's
listed. Might need the hub in hand as well to determine?
Actually I may have figured it out. I think it's 28.5 - 31.5 = -3mm for the offset?
Shown here at 03:20 in the video:
Here are the specs on the DD rear hub motor: Motors for Electric Bikes: New QS159.8 E Bike Hub Motor
I'm asking the factory to install an L1019 connector and NTC 10k thermistor with a beta value of 3450 before shipment. I will pair this with a Baserunner L10 and will run dual V7 torque arms on it for regen.
QS159.8 E Bike Hub Motor (Direct Drive)
This is what I get so far:

Or I could put the left elbows "In" for a better tension ratio. I'm leaning toward this for balance and I can order all 115mm length spokes.

Interested in all the feedback I can get. Thank you.
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