Will Luna Eclipse mate to 130 BCD 5 bolt Gates CDX sprocket?

[Alpinist]

I am attempting a Gates Carbon drive on my second build (new Soma Wolverine frame and transferring most everything from my first build http://tinyurl.com/j6veqb2 onto the new frame).

My question is; if undo the bolts on the Luna Eclipse, remove the toothed ring, then attach the adapter section to a 130 BCD 5 bolt Gates sprocket, will that work?

Does anyone have experience with putting a non-Luna chainring on the Eclipse?

Thanks for your help and suggestions.

[brucemetras]

Doubt that would work.. the Eclipse spacing doesn't look close to being compatible with 130bcd chainrings.. I don't think you'll have much luck going belt drive unless you can get a suitable 'chain/belt line' with the 130bcd or 110bcd adapters that are available to mount your Gates Sprocket.. problem, the belt will move outboard quite a bit at the bb .. so you'll need an extra wide rear triangle to get the cog to line up with the front sprocket.. the Wolverine looks to be a great frame for belt drive, but I'd mock up something first before spending all the dough on Gates drive .. happily, you already have the BBSHD, so will be easy to check for belt alignment issues..

[Alpinist]

Thanks for your help. I'm hoping I can work something out through purchased adaptors or maybe machining one myself if I have to. I can always keep the chain drive , it's dialed in and good chainline. A gates drive would be cool and hopefully a fun challenge

[Eric Luna]

HI Alpinist,

I have been thinking about writing a story about this subject...

but its true....adapting a belt drive to work with a mid drive is no easy task.

and what someone said about the eclipse is true ....it is not your common 130 bcd.


Just think of it this way.....what belt driven commercial bike is available on the market right now? iyes sondors thin...but that has a hub motor..which ebike belt driven has a mid drive?

Even optibke does not have one and they sale for 17k....

If you are thinking about creating a mid drive / belt drive it will only be worth the expense and time if you are gonna plan to bring it to market (which i encourage you to do)....

if you do manage to make one and make it bolt on with the eclipe i promise to help sell them for you because i think there is a market for them.

its not worth it if you are making just one just for yourself....

and there is no easy off the shelf answer or it would have been done by now....

but really encourage you to do it anyway :)

[MsCynthia]

Faraday has a couple of models with belt drive and an IGH......and a 250-watt front hub motor with a 306Wh battery for $3500.

[Christian Livingstone]

Gee,

What about the $49 two-piece adapter ring?



I mean, it undoubtedly doesn't have quite the offset of the Eclipse, but it looks ready to bolt a 130 BCD Gates ring right to it. And since you're using an IGH the belt line may be forgiving enough.

Otherwise, yeah, it always seems a cool thing, to me, to doing something thats apparently never been done before, even if it doesn't seem marketable.

But if there is a simple bolt-up solution, then some eBiker may consider a belt drive, even though most frames won't allow for a closed-loop drive, i.e., no master link.

[spinningmagnets]

Gates has four-arm 104-BCD chainrings, and also five-arm 130-BCD chainrings (pulley-rings?). Stick with Gates CDX format, the older Gates CDC and Schlumpf are hard to get, have limited selection of tooth-counts, and are being phased out.

http://www.gatescarbondrive.com/Products/CDXSPROCKETS

This is definitely worth exploring, but...the biggest problem as I see it is the "chainline" . Chains can tolerate a lot of sideays deflection if needed, in fact that is required for a derailleur and sprocket-stack to work at all. Belts MUST align straight.

A belt "might" work for the BBSHD, but...I see its largest initial customer base being a BBS02 with an IGH. The best bet for a first try (IMHO) would be a cassette rear wheel. That way, you can slide the pulley back and forth on the splines to get the best possible alignment. Of course this would make the bike a single-speed. However this would allow you to get your hands dirty before buying an expensive IGH.

If you decide to make a custom aluminum CNC spider with enough off-set, maybe consider making the diameter large enough so the BBSHD can fit it, and have 10 center holes, five in the BBS02 pattern, and five in the HD pattern? (maybe not possible, I know)

Gates is very big into turn key factory ebikes (Bosch/Yamaha/etc), so there may be pressure to NOT help kit manufacturers, but...they have shown they are interested in covering the widest possible number of interfaces so another belt-interface manufacturer (Sondors?) doesn't get their toe in the door.

[spinningmagnets]

I just remembered that SRAM has the :"Dual Drive". It is a 3-speed IGH coupled with a 7-speed cassette. Remove the sprockets and you have a 3-speed IGH with cassette splines for the pulley, so you can move it in or out for the best possible location.

[Alpinist]

Thanks Spinningmagnets for your great suggestions and advice. I will post about progress as (or if) I take it on. :)

[Alpinist]

I was also thinking about re-purposing the ugly steel stock chainring into an adapter that I can drill various attempts at hole pattern and spacer rings that mate to Gates front sprocket ring thingy (while prototyping/dialing in the chainline offset) - it might work but nothing I would want permanently.

I am planning on modelling the basics of the eclipse in Solidworks and trying to work out what I can in 3D before I start machining a chunk of aluminum.

Check what this guy did, nice job on what looks like a 750w BBS02?

[brucemetras]

I think the Honey Badger uses a 148 mm rear axle .. the Wolverine, 135mm .. that would be approximately 7 mm more for the Badger to play with to line up the belt.. the Badger builder also had to dent his chainstay to get the motor further inboard .. you'll have a good challenge for sure .. I like your thoughts to using a stock chainring for the offset, and just bolt a belt sprocket to it.. Hopefully you'll be able to move the belt close enough to the frame.. let us know what you come up with.. I've been running a belt drive Moulton for years and really like it.. on my particular bike with 120mm axle, I threw in the towel early .. haha ..

[Alpinist]

I did not realize a 130 BCD will not fit around the BBSHD clutch housing - that's a pain in the butt. Not stopping yet. Still trying to get the beltline toward center as much as possible.

[spinningmagnets]

Oh my! looky what we have here! BBS02 with gates belt:

https://endless-sphere.com/forums/viewtopic.php?f=28&t=71057&p=1195798#p1079610

[brucemetras]

Yes, see post #8 in this thread..

[Alpinist]

I can't figure out if Mr. C-cap modified a gates OEM belt ring or not? I don't see material to receive the bolt arms for a 130 or 104 BCD and it appears to be bolted on to the custom machined aluminum adapter ring.

As you know, the BBSHD has a much larger clutch housing that prevents a standard 130 BCD from being positioned inboard and around the housing like the Luna Eclipse does and also the stock steel chainring.

I need to get that front sproket centerline as close to my chainstay and bottom bracket as I can - to have a chance at making a nuvinci work (with its +/- 49mm chainline).

super nice build C-cap did, i'm impressed: This is what I am pointing to


photo from Endless Sphere, taken by c-cap (https://endless-sphere.com/forums/vi...95798#p1079610) - sorry C-cap, I did not get permission first. Happy to take it down if it's a problem.

[brucemetras]

Looking at a CDX sprocket, there appears to be enough meat to machine off the 130 bcd mounting holes and drill holes at the perimeter ...the other side of c-caps build , shows lots of little bolts at the perimeter of the adapter plate .. I'm guessing he's using over the counter CDX sprockets, machining the interior webbing off, then drilling and centering on his purpose built adapter.. could be wrong, but that's what it looks like to me from pictures..

[Alpinist]

thanks for the input, I thought that was what he was doing but I got a little thrown off because my gates spocket looks nothing like the pics above. There are way more cut-outs for weight reduction, but just enough to put fastners near the edge.

[spinningmagnets]

I am collecting info for an article on switching to a belt-drive, so this is all new to me. I am unsure if the belts are up to the power output of a 1500W BBSHD, but I would not hesitate to use one on a BBS02, if the parts can be found that bolt-on.

I would be comfortable having a pulley-ring as big as necessary to adapt the the BBS02 (as opposed to the chain-ring trend of having a smaller chainrings swapped-in), because the pulley on the rear wheel can also have a large pulley to keep the RPMs up on the motor. It is good to have as many teeth on the belt as engaged as possible for strength. By that I mean a 50T/25T pulley set is better than a 40T/20T. the 2:1 ratio would be identical, but the 50T/25T set would have more teeth engaged, so each individual tooth would have less stress on it.

Pedal-bikes don't care about that, and want the absolute lightest pulley/belt set possible, but...motors definitely need more strength, if the only penalty is a few extra grams of weight.

[Alpinist]

I was thinking a similar thought about pulley size and having the most amount of teeth engaging the belt. Currently I have a 60T front and a 24 rear, but I shall find out soon if the 60T will fit without hitting the chainstay when inset toward BB as much as possible to get a straight beltline.

As pointed out by you and others... The Nuvinci is maybe the biggest hurdle since its sproket / chainline is at 49mm +/- because the shifter is inside the dropouts. The Rohloff and Alfine have solved shifting in other ways so the sproket can be much further outboard. Further out is much better for the BBSHD since it is already way out there.

I may end up reverting to my chain solution with the Eclipse, it works really well and is simple. Then save up my money for a Rohloff and do it right with a Gates drive.

to be continued

[spinningmagnets]

Dear c-cap. Before you even posted this, the idea was bouncing around the bicycle world. What I am saying is that: if you are interested in making these for sale, there is a narrow window of opportunity to establish yourself as the "go to" guy. I suspect it is CNC machining, so clearly you have already done the homework on designing the CNC programming to squeeze out hundreds of these. Why should someone else make money off of this, when you could do that? It may only be for a six months or so, because you are not the only guy on the planet that has these skills. If you crank out a pile of the required parts, I am certain Luna will buy them and then retail them for you. No risk on your part, cash up front. If you wait, someone else will go to the trouble of designing something similar, and you will get nothing. PM me.

[Alpinist]

Hi Spinningmagnets. I too think c-cap should go for it if he/she is interested - I would buy one if made for the BBSHD (instead of machining in my shop) and I like the design. There is a market for these and Luna seems to be the perfect partner for distribution and sales. The stumbling block for the BBSHD is that no OEM gates will fit over the housing - which means you have to cut the arms off and then punch transfer the hole locations from the adapter and then drill or drill and tap the gates ring. This may be a step too much for those bbshd owners.

I don't see c-cap in this thread, so if you don't get a PM, you might try posting your message above on ES in the honey badger thread (https://endless-sphere.com/forums/vi...95798#p1079610)