Giant Anthem Advanced 29er-Carbon all the way.

[Hard Tail]

It's funny in an ironic sort of way, that circumstances conspire to send you down a path that with any other sane thought process, you would never venture. There really isn't any other way I can explain fitting a BBSHD and battery to a Giant Anthem Advanced 29er. That's the carbon frame model. I'd been reading the post about the Swiss engineer that had assembled a light weight carbon mountain bike and this coincided with an advertisement on my local site, for a second hand Giant Anthem Advanced29er for the very reasonable price of $2k Aus. I've been commuting on my current Anthem aluminium model for over a year and haven't so much as thrown my leg over another bike since. My only niggling regret was the fact it was a base model Anthem and didn't have all the bling of the XT components. In a moment of tempory insanity, buoyed by the enthusiasm of my recent read, I purchased the bling laden Anthem Advanced. Then the enormity of what I'd done started to set in. My original Anthem project had been a little challenging but all the answers were available and Luna even offered the aluminium bottom bracket spacers. The carbon frame of the Advanced presented a few more issues.

First issue was mounting the battery. I've never been a fan of simply bolting the battery pack to the drink bottle cage and in any case the space available on the bottom tube was extremely tight. The battery would only just fit between the shock absorber and the upper cross tube. The only option I could come up with was the adapter plate and drill and insert a third 5mm rivet nut in the carbon fibre. With shaking hands I drilled into the nice clean carbon frame and gingerly squeezed in the rivnut. Worked a treat. A piece of 50x3mm aluminium flat then made the base of my adapter plate. The plate attached to the frame then the battery screwed to the plate. Just had to notch out a couple of spots around brake cable lugs.

Next issue was the bottom bracket. The Anthems uses those 41OD bearings. I started out with one of Luna's generic aluminium spacers then turned down a shoulder so it would fit through the bottom bracket. Then turned up a corresponding bush for the drive side. The whole bottom bracket was machined to an interference fit and pressed into place with 680 Locktite. At this point there was no turning back. The Advanced would never again be a conventionally powered cycle and possibly only even odds of being a ebike at this point.

Now I had conveniently overlooked the fact that I was relying on the locktite to prevent the whole aluminium assembly from ever moving or rotating in the bottom bracket. A post for assistance was answered by JPLads who quite correctly pointed out a requirement for torque reaction bracket to compliment my press fit bushes. The bracketing solution I eventually settled on was to fit a 5mm bolt through the bottom shock absorber mounting pin. This also required a .5mm walled internal brass spacer to take up the bolt slack, then a modified steel mounting bracket on the non drive side and a curved aluminium bracket on the drive side.
I've only done about 300klm on my new ride, but honestly, it's got to be the best commuter ride around. The lighter weight really makes a difference and the suspension is a dream. I might even have to change my moniker to Soft Tail.

It's been an exercise outside my comfort zone, putting this one together, but if you're up for a build challenge, it's achievable, the end result is most definitely worth it.

[Kammo]

Interesting solution to bottom bracket mount. Building a giant anthem at the moment. Gonna try this solution http://solarbike.com.au/high-power-e...mountain-bike/

based in melbourne as well. Would be great to catch up discuss build and ya your bracket mount.
Did you custom make bracket mount or buy it online somewhere?

[Hard Tail]

Hi Kammo. These brackets are mark 1, home made. With the benefit of hindsight and experience the Mark2 would be slightly more refined, but they still work fine. I’ve sent my number. Feel free to get in touch.

[Sewcrates]

Nice job! I've got an Anthem X Advanced as my vanilla bike.....I briefly considered trying to add the BBSHD to that, but I bought an aluminum Trance instead.

[Hard Tail]

Thanks Sewcrates. It’s a beautiful bike it ride, but quite a bit of work and head scratching to get there. The Trance is considerable easier to convert. If you’re ever up for the challenge of doing the Anthem Advanced let me know and I’ll send you the specs.

[laserman09]

Hey Hard Tail. Just saw your build. It's is beautiful! I have a 27.5 Anthem Advanced that I have been wanting to build for some time, but was hesitant as I hadn't seen anybody been successful on the anthem carbon frames. I've been doing a lot of reading on the bottom bracket part which to me seems the hardest. So with the Luna PF41 100mm adapter, did you have to do any modifications to that? Also, I liked how you used the bottom shock pin as a torque bracket. Where did you get those mounting brackets? Did you make them? I'm really excited after seeing your bike. Any advice would be awesome. Thanks!

[Hard Tail]

Hi Laserman09. Thanks for the interest. Yes, it is a beautiful bike both aesthetically and to ride. ( but I might be biased) Ive got about 800klm on it now and actually off for a big country ride tomorrow. My only slight reservation here is my Anthems are both 29ers but I’d be fairly confident that the geometry and sizing on the 27.5 would be similar and the build achievable.
Re the bottom bracket. Giant have machined a step into the Carbon bottom bracket then inserted aluminium sleeves that accomodate the PF41 bearings. Because the sleeves are slightly recessed there’s a slight step so the Luna adapter won’t simply press in. It does provide a great starting point though but you then would need to turn down one end and make an adapter bush for the other end. Option two that I also considered was to get in side with a de burr tool and grind out the ridge so the Luna bush would then press through. If you have access to a lathe, then option one would be easier.
The bottom brackets were also home made. I just welded the additional arm to the standard Bofang bracket. The drive side is just a strip of 2mm aluminium plate.
The bottom shock pin is actually quite straight forward but again easier if you have access to a lathe. I basically just put a 5mm drill through the end cap and then a 5 mm hardenen bolt went straight through the centre of the pin and picked up the brackets on either side. I also added a small 6mmOD 5mm ID bush that I lock tighted inside one end of the pin.
Im making this all sound harder than it actually is. If you’re going to have a crack at converting your bike them message me and I’ll dig out my shop sketches and dimensions and send them through. Happy to help if I can.

[Hard Tail]

Been enjoying some coastal riding recently.

[Rider]

Very nice builds! That looks like a beautiful place to go for a ride too. Any issues in the rough stuff with the low hanging motor position?

I didn't think any of the carbon MTB bottom brackets were thin enough to take a Bafang motor due to the small gap between the motor and the part that slides through the BB. Does the BBSHD have a larger gap?

With your lathe and machining skills you need to produce a batch of BBS02B 100mm bottom bracket inserts for the Trek 1120 "PF92" and start making some of your E-bike spend back. ;-)

[Hard Tail]

Hi Rider. Thanks. Yes, the Giant Anthem must be the exception. The B.B. on the carbon is basically the same thickness as the aluminium model.

[rhys511]

This has worked for me..

https://electricbike.com/forum/forum...me-bbshd-build

[Hard Tail]

Nice ride there rhys511.

[driftingskyline]

Hard tail, Thank you for sharing your experience. It is helpful! I have the same bike a 2017 ANTHEM X ADVANCED 29ER. I have been strongly discouraged to put the bbshd on the carbon bottom bracket, it was explained that it would crack under the torque pressure from the motor. Have you had any trouble with this on the carbon frame?

[Hard Tail]

Hi driftingskyline. I’ve had no issues now for the two years I’ve been riding it, and I commute on this bike daily 50klm. It’s a dream to ride with the Maxis Hookworm tyres and soft suspension settings for my bike trail and side road commute.
The advice you’re getting on not fitting the BBSHD is correct if you were to adopt the standard high torque grip setting onto an unbushed bottom bracket. I agree, it would crack the carbon sooner or later. (Probably sooner) The method I’ve used only loads up the aluminium bushes and possibly to some extent, the anti rotation bracket. Happy to assist with my old shop sketches if you decide to pull the trigger on this project.

[driftingskyline]

Hi Hardtail, thanks for the response. Do you think if I used this adapter it would help the motor grip the aluminum instead of my carbon bottom bracket-https://lunacycle.com/pf-41-adapter-for-pressfit-bottom-brackets/

was your bottom bracket a pf41?

is this the anti rotation bracket that you are referencing?

below is a picture of my bike for reference.

[Hard Tail]

Hi Driftingskyline. Nice bike but unfortunately no. This kit would be perfect for an aluminium framed Giant Anthem and although they would fit the carbon framed Anthem, when you torqued up the BBSHB nut, you would actually be compressing the carbon bottom bracket. To complicate things further, there is a raised ridge In the centre of the bottom bracket which prevents a single spacer bush being pressed through the bottom bracket.