Surly Moonlander BBSHD build

[leerjet1]

Just finished my project. Its a Surly Moonlander BBSHD 120mm. Used a Lekkie 40t and had to rearrange the cassette for proper chainline. I moved 2 small gears to the inside. Battery is a Luna 52v Wolfpack 13.5ah with the magnetic mount, which is really secure. I did use a Grin triple battery bob under the magnetic mount and drilled and added a 3rd rivnut to the frame. Lots of spacers were needed to fit this motor properly, but it all came out well. The shift sensor is really nice, it only cuts power for an instant while shifting. I'm very impessed with how quite and smooth this is. I was worried it would be too fast for my needs, I ride woods trails with my small dog chasing me, between 7 - 9mph. (short legs) but it is very doable in the lowest assist. Bought the tuning cable, and will play around if needed, but so far it seems fine as is.

[73Eldo]

Cool. Glad to see we finally got a write up on a Moonlander. I know its been brought up several times but if anyone has done it they have not come back to to give us details. Taking lots of spacers was what I remember thinking the one time we did get some pictures of one of these. I have a Pugsley with a BBSHD and it just barely works so with the Moonlander having another 15 ish mm of offset and able to take like 1 1/2" more tire didn't seem likely to just work.

I can't quite tell what you did with the cassette? Which 2 did you pull out? I assume you have to leave the 11 in because its got the locking teeth for the nut. I'm trying to remember if mine was a stack of 4, then 3 then 3 individual ones? So you have 9th-8th-1-2-3-4-5-6-7-10 ?

Mine has a couple spacers and a Lekkie 42 that darn near touches the chain stay and I can do all 10 gears. Its not a great chain line but I'm not running any sort of guide and I have never had any drops or skips even when banging around the trails at the mountain bike parks.

For those playing along and don't know what makes these 2 models unique is the Pugsley is basically credited with being the first mass produced fat bike in 2005 and it was only discontinued in 2020. Back in 05 there was really no fat bike components, it was pretty much all DIY that involved a lot of creativity and fabrication. Some things Surly just had to get someone to make for them like tires and rims. Other things like hubs they just had to figure out how to use what was available which at the time was only 135mm MTB. To make a 135mm hub work with 3.8-4.0" tires they built the wheels with an offset then offset the rear dropouts in the frame to center the tire back up.

Moonlander cane out a few years later to take even bigger tires but still using the 135 hubs so even more offset required. Ice Cream Truck is basically the current version of these bikes but uses the fat bike hubs that became available so no more offset wheel building and frames. The offset was to kick the cassette out to clear the tire. You can easily pick these bikes out if you are behind one on the trails, you don't see the rear brake disc or caliper from behind because its tucked into the wheel.

The Pug stayed in the lineup all this time because you could get it with an offset front fork which allowed you to run an offset rear wheel in the front. This was seen as a cool feature for the ultimate adventure bike because you could have a different size cassette to swap to the back or even something more unique like a single for fix gear. Before the Pug/fat bike Surly was known for to be a big supporter of the single and fixed scene. Kinda similar to the fat bikes, they saw what people were hacking together and saw a market to just sell them what they wanted.

[73Eldo]

Templates? Sounds handy, I didn't know there were such things. Got any links?

[leerjet1]

I printed these on paper, then transferred it to cereal box cardboard for stiffness. https://intercom.help/bafangusadirec...ment-templates

[leerjet1]

More fitting help; https://intercom.help/bafangusadirec...t-on-your-bike

[Tdisa]

Just amazing. I've been falling into despair by not finding any builds with moonlander. You saved me. I'm currently trying to build Bbshd for moonlander and for Wednesday.
Do you think you could fit a bigger blingring or would it be too hard?
Also, pardon me for dumb question, but do I need to buy the spacers from the place that sells the motors also?
Cheers from Finland. :)

[leerjet1]

The 40t chainring provides the best possible chainline, speeds are still fantastic. I've had it to 25mph and I was in the 3rd largest rear gear. Way more speed than I need. I wanted climbing power, and it has it in spades! Any bigger chainring will compromise the chainline. The spacers are available many places. I got mine from Bafang USA directly. Buy this and you will have enough to do the moonlander. https://www.bafangusadirect.com/Prod...ProductCode=85 The 40t lekkie chainring kit also had 2 spacers for the chainring, and I used the thin one for best fit.

[LucasM]

This is amazing. I have a Surly Neck Romancer that I was considering putting an electric mid drive on, and then a glittery Moonlander frame entered my life and I built it up and love the monster tires! But I had read somewhere that they were really challenging or impossible to fit a bafang kit on due to the unique bottom bracket and chainline. I am about to sell the Neck Romancer and was feeling tragic that I will never be able to put an electric kit on it, but it looks like I can pull it off! Thanks for all the great info.