Namida12

I want to adapt 135 bcd campagnolo crank arms to a gates belt drive 52 cdx tooth front ring. Do not find an adapter is anyone making a custom adapter?


I have a KBO Stealth Hurricane eBike that I am trying to lighten to carry up and down three flights of stairs several times a day. Originally the Hurricane Bicycle fully assembled without pedals weight was 37.7 pounds, it now weighs 32.26 pounds. I purchased the square taper campagnolo carbon fiber crank arms to fit the bottom bracket, thinking Gates would sell me a custom size belt drive ring, but they only do 6 bolt 130 bcd, and will not sell me a undrilled blank.


Looking at the 50T 5-BOLT DI2 CDX Gates front ring it is offset I would think a carbon fiber circle would fit inside the ring offset and a 135 bcd could be drilled at the edge of the 130 bcd hole arrangement and that would be the lightest adapter possible. I do not weld, nor have the ability to machine or fabricate what I am envisioning, but there must be a fabricator that could help me secure an adaptor to lose a pound more off this KBO eBike, since I can not find, or begin to afford a carbon fiber eBike road bike frame from a 24 or 26 pound Ribble, Orbea, BMC eBike...

JR

Barry2 

Might help

Barry

veganbikes

I wouldn't put a ton of money into that bike it is a very low initial cost online e-bike. It is not really a good candidate for upgrade but something to ride into the ground and buy the bike you want. If it can actually fit a belt drive which looks like could be possible you would need a belt drive freewheel which is around $200 and a belt which is around $100-160 and then a front belt ring which are usually $60-100 and that is a big chunk of change for a $1000 online e-bike to lose minimal weight.

Unfortunately no adapters exist to convert the odd Campy standard to anything else that I can recall that are going to work well with belts but there are folks who can make you one but that is more money and then you are getting close to half the initial cost of the bike.

I love Gates especially they have been really excellent to me and they make a great product they stand behind, it is lower maintenance and great for commuting but generally it is something I would want to get with the bike from the factory, they will have worked out everything and found a solution that is practical for that bike and since you are buying it from someone who buys the stuff in bulk you are getting a little discount but generally you are likely getting a higher quality bike which will cost more initially but be cheaper in the long term and will work a whole lot better and hopefully have good warranty support as well.

if you are super desperate to spend a ton of money on stuff that may end up not being useful on another bike then I would get a crankset either from Gates or that will fit the BCDs they sell. Adapters will just add weight and square taper stuff is not always light and with Campagnolo they use a different B.B. taper which is not as common (though not wholly uncommon). Though really just save your money, the more you lift your bike the stronger you will become and with some of the higher quality motors like Bosch, Brose, Shimano and probably others they do have a walk assist feature to help get you up hills and stairs I use mine all time.

HillRider

It would be a lot cheaper to buy a pair of Shimano 130mm BCD crank arms in either square taper or HTI or HTII format. The weight gain would be minimal and the cost far more reasonable.

A better question. Is your bike currently a Gates belt drive? The KBO website shows a belt drive model but says they are switching it to a chain drive. So, what do you have?

grumpus

nothing much, because it comes from the factory with a belt drive? OP is just looking to fit lighter cranks. I've adapted a (OPC BMX) chainring to fit something incompatible using a jigsaw, a drill and a file. It wasn't hard to get a good fit. Without pictures I'm just guessing but wouldn't it be easy to just use a scrap Campy chainring as an adaptor plate?

veganbikes

I looked it up on their website it was a chain drive with probably the cheapest KMC chain.

grumpus

I wonder why they sell this then.

veganbikes

Unsure which is correct then, as they list that bike as a KMC chain driven bike.

grumpus

I expect they switched from belt to chain without changing the model designation, and the OP has an older one.

veganbikes

Totally possible, manufacturers change specs all the time and I have seen a few who do conversion kits for belts as well.

Macguyver909

Belt drives are very fussy about radial runout. Gates spec is .009" total radial runout for the sprockets. This is going to be harder than it sounds to get right. Here is a link to the gates design page. If you have time, there is a lot of info in this and other Gates drive links. Gates is VERY specific spelling out what will and will not work.

https://en.calameo.com/gates-corpora...d=T6ormLwju01x

Namida12

This bicycle was a May 2022 purchase from KBO

I vacillate between a number of eBikes before making a purchase. I wanted a light weight unit to carry up and down stairs, but could not afford a $4,000+ major manufacturer offering a 26 pound carbon fiber framed eBike. I brought the choice down to Ride1up Roaster or a KBO Stealth Hurricane. Ride1up had not released the Gravel model, nor the extended battery when I made my KBO purchase. The KBO offered the larger battery for more range when I made my purchase. What I discovered riding the KBO Hurricane a number of miles is the cadence sensing is not good for hills, as a rider starts up an incline their pedaling speed slows which sends a message to the controller that the rider wants less power assistance. Whereas a bicycle equipped with Torque sensing depends upon pressure on the pedals which is normal instinct for a rider when encountering a hill, press harder on the pedals to increase more drive, or power assistance from the motor to help reach the crest or speed necessary to climb the incline. Next step to improve power assist. (Sorry kinda went off subject)

The other complaint about my eBikes purchase was the weight, 37.7 pounds does not seem to be much weight, but carrying the bicycle up and down the narrow stairwell is not fun. I am looking to save weight using parts I or my close friend had in the our parts bin to reduce the eBikes weight, and after more changes than I wanted we managed to get the bicycle down to 32.2 pounds, that has allowed me to negotiate the stairs and hallway much easier when I am tired, or not quite awake after a night out. I purchased the KBO after watching a youtube review of a 220 pound reviewer exhaust the battery at 32 miles, much further than the Ride1up Roadster was able to travel with a 170 pound reviewer.

Changing out the generic belt drive to a Gates unit will bring down the weight almost another pound, and give me a better drive ratio choice to deal with long gentle inclines at the expense of downhill top end speeds (not needed in Traffic) offered by the generic 59 tooth front belt ring. What about having an accomplished aluminium welder fill the drilled holes in the Gates Belt ring, and have it redrilled for 135 BCD? Maybe that would be better than using a carbon fiber sheet adapter...

JR

Namida12

The hurricane I have is a generic belt drive setup that is heavy, compared to the gates setup...

Ride scoozy Torque1 is also a chain drive eBike, the frame is not split so a gates belt drive can not be used but it has Torque sensing...
https://ridescoozy.com/Electric-Bicy...rque-One-Ebike

grumpus

That's possible, I bought a torque sensing bottom bracket on AliExpress for not much, but I haven't got around to using it yet. If you're going to use one I suggest sorting it out before finalising the crank arrangement, as it has its own spider (so uses a drive side crank arm with no spider).
That depends on the alloy that Gates uses - something that's good for forging may not be good for welding. Maybe you could locate a scrap toothed wheel to experiment on.