MID drive and Gates Carbon Drive

Joined
Aug 25, 2011
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212
Hello All,

Been bouncing all over the place on a bike to convert for a work commute as well as hub vs mid drive. I have narrowed it down to a Cannondale Contro 3 or a Priority Eight. Both are similar in price with the Cannondale being about $100 more. Converting the Contro 3 is a no brainer for a BBSHD with the standard chain and derailer. The Priority eight however has the carbon drive and an 8speed Nexus hub. First off is there a way to adapt the Gates crank gear to the BBSHD, or is there already an aftermarket gates friendly gear for the BBSHD? Second, is the Nexus 8 rear hub strong enough to take the torque of an electrified bike? Also getting the belt line needed might be next to impossible unless there is a way to add the existing gear to the Luna Cycles gear which offsets the gear inward a bit. Designing one in solidworks would be easy for me if needed.

One plus with the Priority eight is I can aslo go the front hub route instead of mid drive if I like. Whereas the Contro 3 having a lefty fork would force any hub motor to the rear. However, I do like the look and some of the components spec on the Contro 3 better.

Looking for advice...

Marc
 
I have a Nexus 8 igh + BBS02 750w combo. So far (a few hundred miles) no problem with hub in normal street use. Can't say about BBSHD with extra torque.

Separately I have a pedal powered bike with Gates carbon belt + Alfine igh. Man I like that bike. Smooth, silent and no damn greasy chain :wink:

Have thought about a BBSxx + Gates belt drive project but haven't tackled it yet because the Gates demands an essentially perfect chain line.
It could probably be done, but we need a pioneer to figure it out. Volunteers? (If somebody comes up with an adapter, I'm happy to be first in line for purchase...)
 
Thanks for the reply Footloose,

I reached out to Priority to ask for the dimension from the mid line of the bike to the mid line of the belt to see if I can figure out if it would work with a BBSHD.. BBSHD may be too much for the Nexus however. I do have a nuvinci developers kit I could use but now this is getting a bit crazy as I wanted an easy drop in solution...
 
Not speaking from personal experience but it was something I looked at, there is a 130BCD spider for the BBSHD about (cali ebikes I believe) which fit the 46 up to 70 tooth gates CDX sprockets. There's more than a few people here that are running the BBSHD with the alfine 8.
 
Grautuefel said:
Not speaking from personal experience but it was something I looked at, there is a 130BCD spider for the BBSHD about (cali ebikes I believe) which fit the 46 up to 70 tooth gates CDX sprockets. There's more than a few people here that are running the BBSHD with the alfine 8.

Thanks for the info on Calibikes. I had a look and they do have an adapter that may work. Also the Priority eight has a nexus 8 and not an Alfine 8. Teh Nexus is not as stout so curious if it coudl take the load. Also I have been entertaining the idea of a MAC350W front hub instead.

Best regards,

Marc
 
Gates do a big manual for their carbon drive giving all the dimensions for different frame setups (to give you an idea).

Basically you would have to measure where the front crank pulley was and make sure it ends up in exactly the same place after the mid drive conversion, they are not tollerent to any misalignment.

I have Carbon Drive on my Gtech and it's silky smooth, well worth the effort to get it working if you can!.
 
Make sure the bike has the CDX front pulley, the CDN composite pulley probably won't be up to use with the mid drive..
 
I'd be careful how much power you put into the belt. I don't think they were designed to transfer super aggressive torque to the gears. I could be wrong...
 
You need a special frame that has a removable piece to get the belt on. That rules it out for most amateur builders. Full suspension frames sometimes have removable members in the rear triangle, so that could work if you replaced the shock with a fixed strut to prevent any movement.
 
I've been trying to research this as well though I'm a complete beginner so currently struggling. I found the Gates Integration Ebike manual though they use Bafang Max. Please let me know if it's possible to integrate the BBSHD. Also, what is a CDX mounting surface A?

http://www.gatescarbondrive.com/~/media/cds/documents/oemfactoryresources/gates-cd-ebike-compatibility.pdf?la=en
 
I think that's referencing a type of mid drive install where the frame has been built for a mid drive (as well as a Gates belt, with opening chain stay).

I'm ambitious to use a Gates compatible frame and a BBSHD to make a bike like this one. I don't know where this bike came from, I found this picture on alibaba (lost the link).

 
alot of info on this page
https://endless-sphere.com/forums/viewtopic.php?f=28&t=65093&p=1006791&hilit=gates+carbon#p1006791

building a bbshd / gates set up this week. will let you guys know how it goes and any problems i come across

file.php

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my only question is where is everyone getting the chainrings from? are they custom parts?
 
I'm in the middle of building a BBS02 Gates Belt Drive ride using a Strumey-Archer CS-RK3 rear IGH cassette hub. Although I'm setting it up as a 3spd IGH and using the cassette to align the belt, I should have a minimum chainline from the center BB once my BBS02 arrives and I bolt on the 130BCD spider adapter and 50T Gates sprocket. That measurement should give BBS02 builders a number to work with using store bought parts for other IGH hubs. I'll post up with photos once all the parts have arrived.

BBSHD is a different animal...
 
I made my own chainrings and wheel sprocket for a gates carbon belt using a stack of laser cut laminations. The stack approach gives you fine control of the 'chainline' and laser cut DIY gives you absolutely any ratio you want. Originally my front chainring was ally but that collapsed after ~3000miles so I remade in stainless & that's been fine for the last 7000mile.
My bike has an alfine 11speed, I think the hub connection is the same as the 8speed (and a sturmey 3speed....)
More recently I've been experimenting with 14mm industrial belt instead of the very expensive carbondrive. Fibreglass reinforced belt is simply not strong enough, you need the gates (or somebody else's equivalent) carbon stuff, but I was able to get a 20mm wide belt for £26 (ebay and slice it down into 2 10mm belts). I could only get a 1400mm long belt & that's too long really - makes the "chainring" look silly big....
Here's a picture of the bike
http://i543.photobucket.com/albums/gg471/bobc0/bikebits/alfine11belt.jpg
seatstay break
http://i543.photobucket.com/albums/gg471/bobc0/bikebits/gatessprocket.jpg
this is the glass reinforced belt that stretched & stopped working
http://i543.photobucket.com/albums/gg471/bobc0/bikebits/Dsc01550_zps8b0f7f53.jpg
 
Yes, the hub connections for an Alfine 11 and an Alfine 8 are the same, you can use the same cog for either. Cogs are available with 22, 24, and 26 tooth. They changed the type of connection for this family of cogs, I've used both. The new type can require some levering to get it fully seated. More here: http://www.gatescarbondrive.com/~/media/CDS/Documents/Gates-Tech-Bulletin-Surefit-13-03-28.pdf
 
Received my BBS02B 750W, 130BCD spider adapter from France and Gates 50T front beltring. All mounted up on the 68mm BB, the CDX belt centerline came in at 55mm. The key measurement for others to work with is the BBS02B spider adapter mounting surface that measured in at 56mm (apparently the BBS02B stock chainring has a 6mm dish, because their schematics state the stock chainline is 50mm +/-0.5mm).

Using the Sturmey-Archer CS-RK3 3spd IGH cassette hub and a Gates 28T cog you can set it up all the way out to 57.5mm.

This build is using a Soma B-Side V.2 belt drive frame. Currently waiting for the beltring bolts to arrive to install the Gates Carbon Drive.
 
Another thought that crossed my mind is that it might be possible to combine a larger Gates beltring with a 42T Lekkie Bling Ring to get a whole lot more inward with the beltline. Not all that much more expensive once you subtract the cost of the spider adapter (The Lekkie bolts right to the BBS02B).

One might consider bolting at the chain sprocket teeth or machining them off and welding...

My guess is that will get builders into the typical 43.65-43.85mm range of IGH rear hubs, but you will have to watch the front beltring to rear stay clearance closely.

ADDED: I just went and measured the clearance from the Gates beltring to the BBS02B motor housing and there is only ~10.5mm left to go inward before it hits the motor, so keep that in mind too (maybe consider trimming the BB ~1mm if needed).
 
130BCD spider adapter from France? I missed that part of the thread. Not the one from California e-bikes?

Can you make more pictures please? There is a 46T 130BCD Gates front sprocket, is that out of the question?

TIA!

Edit: Found this from looking at what you have and doing an image search: http://precialps.com/uk/accessories-bafang-bbs01-bbs02/19-adaptateur-130bcd-bafang-bbs01-bbs02.html
I'm guessing it has more offset than the California one. How did you select this one? (Do you have measurements from both?) TIA!
 
Hmm i am very intrigued :?: :lol:
Can you run this with an IGH? That would be my ideal! How does this handle torque? My BBSHD can rip a chain off the sprockets if the chain line or derailer are slightly off. I want to switch to IGH and if i can use this kind of chain that would be stellar!
 
The attached photo shows the ~10.5mm clearance between the edge of the Gates 50T and the motor housing in BLUE and the additional clearance of ~6mm for one-half of the Gates 50T beltdrive inner lip diameter (USING THE SETUP AS INSTALLED) is shown in RED.

Comparing the Gates 50T to 46T specification “Tooth Outer Diameters,” there is 13.9mm difference (173.2-159.3=13.9), so half that would be 6.95mm per radius. That is “probably” just a tad too much to clear the gear reduction hump if you wanted to go inward at all from where I’m running mine (55mm from frame center). IMHO the 46T Gates beltring is too small for comfort.

A 50T gates beltring is the smallest you can possibly combine with a 42T Lekkie Bling Ring and that would require machining off the teeth on the Lekkie and machining out a large matching circle just under the belt cogs on the 50T Gates, then welding them together. I don’t know what size Gates beltring might let you bolt the two together using the teeth “U’s” of the Lekkie without modification and drilling 5 holes in a center modified large hole machined Gates beltring. The outer most diameter of the Lekkie at the end of the teeth is ~178mm.

The second photo is the spider adapter from France I’m using that I bought on eBay. It is flat on the back, but has a 2mm indent where the 130BCD sprocket mounts moving the sprocket 2mm OUTWARD. The 50T Gates beltring is 3mm thick at the mounting points and then you have to also clear the beltring bolt heads. That bolt head measurement clearance is shown in GREEN on the first photo and is maybe 1-2mm at most. You can always countersink the chainring bolt heads into the Gates beltring ~1mm if needed. If the California Ebike Spider is completely flat on the back you may need to do that for good clearance.

That’s about all the information I can provide. It is best to do actual calculations for your application of all parts starting with the BBS02B mounting surface being 56mm from the frame centerline.

One thing is for sure, the CS-RK3 gives you infinite adjustment out to 57.5mm using a Gates 28T rear cog.
 

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Santa'sLittleHelper said:
The attached photo shows the ~10.5mm clearance...
One thing is for sure, the CS-RK3 gives you infinite adjustment out to 57.5mm using a Gates 28T rear cog.

Hey thanks much for this post. I've decided to build out around a CS-RK3 for a new urban bike based largely on your documentation. (I've got my frame fork headset crank, brakes are already on the way, just ordered wheels etc.)

I guess I'm surprised you're going as low as 50/28.

Thanks in advance for any additional posts. I'll put up pictures when I get as far as you have above.
 
APailthorp said:
Santa'sLittleHelper said:
The attached photo shows the ~10.5mm clearance...
One thing is for sure, the CS-RK3 gives you infinite adjustment out to 57.5mm using a Gates 28T rear cog.

Hey thanks much for this post. I've decided to build out around a CS-RK3 for a new urban bike based largely on your documentation. (I've got my frame fork headset crank, brakes are already on the way, just ordered wheels etc.)

I guess I'm surprised you're going as low as 50/28.

Thanks in advance for any additional posts. I'll put up pictures when I get as far as you have above.

Wonderful! Here's some more info on how I installed it and a couple pictures.

I had my brand new Soma B-Side V.2 frame BB faced, so I didn't want to use the Bafang mounting bracket that digs into the edge of the BB. I made an aluminum replacement bracket that attaches to a frame clamp similar to a torque arm. I also wrapped the part that slides through the BB with one layer of aluminum duct tape to insure a very tight fit in the BB and put a small bead of tub caulking on each BB edge as well.

2w3rhax.jpg


This is all installed with stainless steel bolt and cap nut on clamp.

rbabnq.jpg


Got the belt installed over the weekend too.

25qejqv.jpg


All is looking good. The last steps will be to install the shifter cable and housing setup; and decide on the type and style of battery to use.

I'll let you know how the low gearing works out. I went with what Soma recommends for a single speed non-electric assist for the 1:1 2nd gear on the 3spd IGH; partly because I may some day ride this without the BBS02 and it keeps the build CA legal through the gearing without limiting the assist speed. My prior experience with a 350W-36V BBS01 tells me that that ratio in 1st gear will allow me to climb the hills I do in my area without boosting the 750W motor into the peak zone. 3rd should max out at about 18-20mph. I won't be running a throttle and wanted this ride to be a Type-1 California legal ride for "anywhere" a normal bicycle can be used.
 
Been riding her without a battery and loving the quiet and smooth ride. Did 20 miles at the beach a week or two ago as a shakeout ride. Apparently I didn't have the crank arms tightened up enough to get them all the way on, as they came loose on the ride. Barrowed a tool for another rider and that was solved. The only other issue that came up was the IGH cable stop mount that I put on the lower rear stay slid rearward on the tapered tubing (it gets smaller towards the back). Even with 60lb. double sided 3M mounting tape it slid enough to lose first gear. Luckily I didn't need the low first on a beach ride. Since then I have relocated the IGH cable stop that Strumey-Archer provides to the upper rear stay just above the braze-on derailleur stop so it can't slide down at all.

2n0v9y1.jpg


Currently working on modifying an Ibera Mini Commuter bag and rack to install a 21Ah Panasonic GA battery block in. I'm pushing the small quick release rack forward and mounting it to a seatpost clamp with rack mount, plus adding vertical legs off the rear most square side tabs down to the rear axle area frame rack mounts. This should get the heavy 11lb. battery in front of the rear axle and underneath the rider (hopefully).
 
The gates carbon drive belts are absurdly strong.

You're unlikely to find an amount of power or torque that bothers them.
 
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