Any interest in disc brake mounted sprockets?

[neptronix]

Just wanted to throw a line out and see if there is any interest in this.
I am working with a company that can CNC sprockets of various tooth counts that mount to disc brakes.

These sprockets can be designed with #415 ( BMX chain ), or #420 ( heavy duty trike chain, close to the width of #40 ) in mind. I will offer a few standardized sizes, such as 30T, 35T, 40T, and 50T.

I can also have a 2.5mm inward offset milled into the gear, if you need a little extra clearance on your frame to run the chain. This is helpful if your chainstays are particularly narrow, and you are running 2.0-2.3" tires. Often times, a chain drive system is a rather tight fit on some bikes, so this can help get any extra clearance that is needed.
Regular sprockets can be flipped around to adjust the offset of the gear teeth by about ~3mm.

Milled out of extremely tough aerospace grade aluminum.
Price would range from $50 to $70 shipped.

Sprockets would look similar to this.

If there is significant interest in something like this, i can get a design ready, post some pictures up of examples, and get some of these bad boys made. Raise your hand if you're interested in a product like this.

 

[gestalt]

here's some good ones from king sales and service, you might know them as the makers of the top hat adapter for running a sprocket and a disc brake on the same hub

http://www.kingssalesandservice.com/


the silver ones go for $42 for the 26-42 tooth range going up to $72 for the 80 tooth ones. I have picked up these for the gas engine kits and the fit and finish is great. They have them anodized in all kinds of crazy colors for more $, worth it if you are going for some matchy-matchy with your ride.

though they only run the heavy duty chain, some large disc mount sprockets at a reasonable price running bicycle chain is a great resource. thanks for hooking that up nep.

 

[neptronix]

Yep, ordered 2 of those and had problems with my order both times. Seller uncommunicative after the sale. Bad machining on the tophat adapter - it has 8.5mm holes instead of 8mm holes, leading to indexing problems.

[youtube]_VSBb2FZ9FI[/youtube]

So i am going to produce something that has sort of a tophat adapter built in ( if you want it ), which does not require extra bolts that just add weight.

So you can either buy from me ( i have tons of good feeback on this forum! ) or roll the dice with him ( has some bad feedback on eBay, multiple comments about items not being delivered on his youtube site etc ).

Of course i am a little biased... :lol:

 

[Trilska]

Seems interesting to me, and the size of around 50t would probebly be the most useful, not to big and heavy but yet still allow for a substantial reduction.

Ps. I enjoj the way you deal with an inferior product. "If they cant make a proper job, i do it myself." Ds.

 

[recumpence]

A couple things about King Sales sprockets;

#1 You need much more than a couple MM offset for most applications.

#2 The customer service is TERRIBLE. I sent $140 for two sprockets. They were made incorrect and when returned, he lost my order and had no record of it. At that point, I was beyond the time limit for Paypal to get my money back.

If you ever talk to the guy on the phone, you will see what I mean. He is strange.......

I normally try to stay away from talking down on anyone in the industry. But, this is one company that is absolutely terrible to work with.........

Matt

 

[neptronix]

Thanks for you feedback, recumpence.

Yeah, i know about #1 from first hand experience. You can't use really large sprockets on regular bikes because of the angling of the chainstays. It sucks. But a disc brake hole is one of the best ways to go about this. A few MM of inward offset helps you get that chainline closer to the wheel, but at the same time doesn't go inwards so far that the chain will rub against the tire, which may be a real possibility when we're talking about 2.5" tires on a 135mm hub... i've had my bike chain verge on rubbing on a maxxis hookworm before..!

#2 yes, i figured i was not alone on that one. I've seen many reports on the motor bike forums. But he is literally the only guy selling this stuff to end consumers.

It doesn't look like there's enough business here on ES to justify getting into the biz. I could produce sprockets at a lower price than him if there was enough demand, but if it's just an order here and there, my cost would be a little higher. Except i wouldn't ignore you when you ask for a return, or go on a 30 minute rant when you called me on the phone.. is that a value added bonus?

Maybe people have lost interest in chain driven stuff lately since hubs are so damn good these days... but damn, they are getting monster heavy..

 

[gwhy!1]

I thought I would just add that oset ( a electric trials bike ) manufacturer makes a disk mount sprocket adaptor for 219 sprockets, not sure of the price as they dont list it in there spares section of there web sites but I will try and find out the price for anyone that is interested, they also sell a custom rear high quality hub (135mm) with disk mounts on both sides. these are parts that are used on there 20.0 oset..

 

[neptronix]

That's interesting, but after some sizing and thinking, i've realized that we need lots of inward offset, like 1/4-1/2in. for larger sprockets, due to the tapered design of most bicycles' rear chainstays.

Yeah, you could fit a 20-38t #410/#41/#415 on most bikes, but what's really desirable is a monster sized 50-70T so that you can do one huge 5:1-7:1 on one stage.

Even though this requires a spendy recumpence disc brake adapter, It saves you quite a bit of money and secondary reduction friction if you are using the following motors:

+ low kV Astro motors ( 50-80kV )
+ MAC/BMC 3.5lb 500W-750W motors ( ~70kv )
+ MAC/BMC 6lb 750W-1000W motors ( ~70kv )
+ MAC/BMC 10lb 1-2kW motors ( ~70kv )
+ Transmagnetic 11lb 3kW motors ( ~73kv )
+ Various large RC - CA120, Rotomax, 80-100, etc.

 

[SkyknightJohn]

I would be interested. I thought I had seen these offered before somewhere, but searches come up empty except for kings', and complaints about them. It seems the ICE world would love a quality version, too. Consider them as potential market as well.

 

[spinningmagnets]

...At that point, I was beyond the time limit for Paypal to get my money back.

I'd like to add for the benefit of new readers (as I'm sure you already know)...the "waiting until it's too late to get a Paypal refund" was no accident.

Nep, If I had to choose between you and any vendor on the web, I would use you, even if it was the same price.

 

[Chalo]

Just wanted to throw a line out and see if there is any interest in this.
I am working with a company that can CNC sprockets of various tooth counts that mount to disc brakes.

These sprockets can be designed with #415 ( BMX chain ), or #420 ( heavy duty trike chain, close to the width of #40 ) in mind. I will offer a few standardized sizes, such as 30T, 35T, 40T, and 50T.

I think these would be a very valuable resource for a lot of e-bike builders. I might buy a couple just to get them while they are available. I have a couple of observations:

Offset sprockets will be much more expensive to make. To minimize costs and maximize versatility, I suggest that the non-offset models be cut from plate between .093" and .120" thick-- the material is inexpensive, very little of it must be milled away, and that would make it compatible with #410, #415, #420, BMX, or track bike chain.

For the offset kind, I recommend a simple plate adapter with a 44mm x 6 pattern and a 110mm x 5 pattern, to fit a standard bicycle chainring. That way, you can offset the ring inward or even outward by any amount from the thickness of the ring on up, by using chainring bolts and nuts along with spacers that are widely available in thicknesses from 0.5mm to 5mm.

Such an adapter system would allow you to manufacture compatible 110mm x 5 sprockets in any width, material, or chain pitch (e.g #219, 8mm, or #35). There's nothing magical about 110mm bolt pattern, but it means that mass produced bicycle sprockets from 34t to 56t can be gotten almost anywhere in aluminum, steel, and stainless steel. Other applicable standardized bicycle chainring patterns include 74mm x 5, 104mm x 4 and 130mm x 5. Those correspond to minimum chainring sizes of 24t, 32t, and 38t respectively.

All the parts could be milled, laser cut, or waterjetted as desired. I'm thinking the adapter would be milled from aluminum for precision, and the plate sprockets could be milled from aluminum or else laser cut from steel (which has the effect of surface hardening the steel).

Another kind of ring I think would be great to have available would be one with an 8-bolt pattern corresponding to the teeth of a 16t freewheel, with a backing ring for the other side of the sprocket teeth. That would allow use on any RH or LH freewheel of any brand.

 

[neptronix]

Ah, yes i realized that sprockets with a significant offsets would be expensive to make when i started pricing out water/laser cutting for them. These would need to be cut from about 1/2 an inch aluminum plate. Yikes! especially if you are cutting the 60-70T sprockets that i'm looking to produce O_O

So, given that we have the recumpence adapter available to us, i will be working to get some custom 130BCD chainrings made, in #410 ( BMX size, good for maybe 1000-1500W setups as a guess ) and #35 ( should take higher power, motor side sprockets are far easier to find ) at the lowest cost possible. I am hoping to do these custom rings around $50-$80. I get them laser cut, shipped to me, then have to do some machining here, then ship them out.

Your BMX freewheel idea is interesting and i swear i've seen another company do it. But the BMX freewheels only take so much torque. Putting one at the wheel, where torque is highest has meant for a short service life for these components, as reported by many here on ES :lol:

It is common for the high powered recumpence drives to use those freewheels though at the end of the first stage of reduction. It seems that they can tolerate the high RPM of spinning at a few thousand RPM, but not the 100-200lb-ft of what happens on the drive wheel.

 

[thepronghorn]

Your BMX freewheel idea is interesting and i swear i've seen another company do it. But the BMX freewheels only take so much torque. Putting one at the wheel, where torque is highest has meant for a short service life for these components, as reported by many here on ES :lol:

It is common for the high powered recumpence drives to use those freewheels though at the end of the first stage of reduction. It seems that they can tolerate the high RPM of spinning at a few thousand RPM, but not the 100-200lb-ft of what happens on the drive wheel.

Thud runs freewheels at the wheel, and he makes some pretty fast bikes. That's why he had to make the nifty contraption in this thread.

http://endless-sphere.com/forums/viewtopic.php?f=28&t=37640&p=548136&hilit=crossfire+splines#p548136

Not sure how easy it is to do this on the left side, but I doubt you'll have problems with the torque and the freewheel.

 

[Chalo]

Your BMX freewheel idea is interesting and i swear i've seen another company do it. But the BMX freewheels only take so much torque. Putting one at the wheel, where torque is highest has meant for a short service life for these components, as reported by many here on ES :lol:

Torque is generally even higher at the crank, because most of us use larger front rings than rear sprockets most of the time.

Most of the freewheel mutilation I see here is on freewheel cranks, where the freewheel overruns while under full chain tension from the motor. That's not what freewheels were designed for. On regular bikes, freewheels only turn when there is no tension on the chain, and they are very robust in such use.

It seems that they can tolerate the high RPM of spinning at a few thousand RPM, but not the 100-200lb-ft of what happens on the drive wheel.

I ran the numbers the other day to demonstrate that a 200 pound rider on a mountain bike should be able to develop torque peaks at the wheel of 270 lbs-ft. Of course in practice this does not happen from pedal torque or motor torque, because the resulting wheelie imposes an upper limit on reaction torque.

 

[bee]

I thought I would just add that oset ( a electric trials bike ) manufacturer makes a disk mount sprocket adaptor for 219 sprockets, not sure of the price as they dont list it in there spares section of there web sites but I will try and find out the price for anyone that is interested, they also sell a custom rear high quality hub (135mm) with disk mounts on both sides. these are parts that are used on there 20.0 oset..

Does anyone have pics of this adapter? It's exactly what I need but the few oset dealers I've talked to didn't understand what I meant!

 

[crossbreak]

the #219 dapter would be something I would give a try as well.

 

[gwhy!1]

the only picture I can find at the moment is this one of the new racing oset, you can just about work out the 219# rear sprocket adaptor.

 

[yawstick]

Curious what the status of this is... can you make sprockets per order? I may have a need for one to go onto a kawasaki kx 85 not sure yet but somewhere in the neighborhood of 60 to 80 tooth.... no offset required. I will have to measure it but guess it has about a 80 to 100 mm hole in the center with a 4 hole bolt pattern around that.

 

[orange streak]

I would pay someone to make me a sprotor (disk brake sprocket. Only 30T or 35T. For 1/8 chain, with 6 bolt pattern to disk brake flange holes. I sure need some leads please.

I also need for my project a 140mm disk rotor with 6 bolt iso pattern. Custom project.
View attachment 1

 

[spinningmagnets]

Great pic, thanks for posting that. Chains are notoriously greasy/oily, but...it IS possible to buy an "O-Ring chain", which is sealed, and is fairly safe to run on a sprotor without greasing-up the disc brake portion...

edit: ES member ferret reminded everyone later on in this thread that wax can be used as a chain lube, and it does not drip.

 

[orange streak]

Great pic, thanks for posting that. Chains are notoriously greasy/oily, but...it IS possible to buy an "O-Ring chain", which is sealed, and is fairly safe to run on a sprotor without greasing-up the disc brake portion...

I was unaware of o-ring chain, just a accidental discovery. O-ring chain is not available in 1/8 bike chain. But sounds like something I wouldn't mind having despite being heavier. A lightweight o-ring style chain, & I still need someone to make me a sprotor sprocket for mounting to 6 bolt hub.

 

[recumpence]

Rebel Gears is the BEST sprocket company I have ever dealt with. I use them exclusively for all of my builds now.

Matt

 

[cycleops612]

A holy idea (it probably has holes in it) is a simple way of getting a rear disc brake equipped trike electrified.

Maybe hunt down manufacturers / retailers of such trikes for them to offer as an option or to promote the sprockets via them?

 

[orange streak]

Thanks for the recommendation. I'll start by asking them about the sprotor. Yea, Id like to go with #219 go kart chain with o-rings. Looks like rebel gear doesn't support #219 sprocket from reading.
You can't make a sprotor disk brake out of aluminum??, that's what they use. The friction of the pads will wear on the sprocket!? Steel would be the next best thing & lasts longer.

Like discussed previously the difficulty to fit chain between the frames chain stays. I have about 1/16 or more of a inch clearance with my 1/8 bmx chain mounted, using 135mm dropout hub spacing. So I hope If I can change the dropout width to 142mm to fit the #219 chain. Hope to spread the yuba mundo bikes steel dropouts. Chain line is fine. Lot of people recommend #35 chain?. I'm taking about 27hp!! 103.6v @ 200+ amps.

I'll have to do some calculations. Do I just change the axle length? Changing the hub would just bring the chain closer to frame again? I've almost got this figured out.

Doing it wright with a motorcycle rim & tire this time! Sorry for any post interruption, but need to get chain clearance.

 

[Drum]

Here's an adapter I made a few years ago to mount a Go-kart sprocket on a disc brake mount.
I made two, and the second ended up travelling from New Zealand to Sweden to help Fastcrille with his build.

I got the rear sprocket adapter back from waterjet cutting today. (Anyone in NZ who wants waterjet cutting done, I have put a lot of work through Roadrunner Manufacturing in Bulls, and have always been very pleased with the result, the service and the price).
Couldn't resist getting out into the cold workshop and finishing it this evening.

As cut, 8mm alloy plate, weight 225 grams. Holes already cut and in the right place.




Machining the spigot for the go-kart sprocket.



Finished. Outer flange and spokes 5mm thick, hub 6mm thick, holes for sprocket tapped M6.


View attachment 2
Assembled on hub with a worn go-kart sprocket I borrowed to take the dimensions off.



For information:
The kart sprockets have a bore of 116.1mm (I think that is nominally 4 9/16") and are attached with six M6 bolts on 5 1/4" (133.35) PCD.
The disc brake mounting has a spigot 32.7mm diameter (on my hub anyway..) for a 33mm bore in the disc (or sprocket adapter) and has six M5 bolts on a 44mm PCD.

I will take the adapter to work tomorrow and weigh it, and post the weight here.
Edit: It weighs 145 grams as I machined it. If I were to do another I think I could get it down to 120 grams easily, possibly lighter if I tried hard..