Clamp Hub Adaptors for Rear Sprocket

With a Cranbrook, the rear hub is 1.5 inches in diameter.
I had the chain jump after very soon after completion of the engine installation. I don't like the uncertainty of centering with the rag-joint sprocket. If it's not centered properly, the chain will go loose-tight on every rotation. Thus, I'd like a more certain system. The jackshaft arrangement using the original pedal chain for drive seems the best, but suppliers want $200 + for them. (I paid $500 for my car, to give you an idea of where I sit on the economic heap). I'm considering a hub clamp.
Does the typical 9-hole sprocket 44-tooth supplied with the motor kit, fit on a 3-bolt adapter (like the bottom one pictured here)? Or do I need to buy a new sprocket too?

The hose clamp ones looks lame. It doesn't seem a hose clamp will provide enough gripping power.

I'm considering this MOTORIZED BICYCLE 1.5" CNC THREE POINT HUB ADAPTER from eBay's
mzpartsmiamimzpartsmiami (6546 ).
 

Chaz

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Jun 3, 2012
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The rag joint works well if installed correctly. Over 5 years on mine with maybe 4 adjustments for parallel in that time. Maybe you need to file out the center hole to make it a little bigger.

I thought the "hose clamp" adapter was lame too until one of our members clarified the application. It is used with the rubber rag joint donuts. The hose clamp design just makes the installation easier and more accurate.

If you get the three hole adapter you will need to buy a specific sprocket. Unless you have the equipment and skills to drill the three holes in the stock sprocket.
 
The rag joint works well if installed correctly. Over 5 years on mine with maybe 4 adjustments for parallel in that time. Maybe you need to file out the center hole to make it a little bigger.
I know the arrangement has its fans, but the time it takes to center it alone is enough of a disincentive to use it. Besides, 0.8 adjustments/year is too many. The centering should be accurate.
Yes, I considered enlarging the center hole on the sprocket, but I was afraid to. I don't have a means (that I can think of) to exactly enlarge the hole in all directions.
...the "hose clamp" adapter ...is used with the rubber rag joint donuts. The hose clamp design just makes the installation easier and more accurate.
OK, now it makes sense. The vendors of these parts are rather illiterate. There hardly ever is a paragraph explaining a part.
If you get the three hole adapter you will need to buy a specific sprocket. Unless you have the equipment and skills to drill the three holes in the stock sprocket.
A simple drill press would be enough, but I don't have one.
Actually, $40 USD is not ridiculous. But the price issue is relevant when the eventual plan is to change to a jackshaft arrangement. Then the hub clamp is extra parts.
I also need a new chain tensioner. The original was destroyed in the above-mentioned chain jump.
 

xseler

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Apr 14, 2013
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I have the adapter from mzmiami........it's a great piece and I've got lots of miles on it with zero issues!! 5 thumbs up for this product! Seems like I got the sprocket (36t) from them as a package deal.......
 

Chaz

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Jun 3, 2012
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Vancouver, British Columbia
Well, I said the adjustments were for parallel alignment, not centering. The centering was dead on since day one.

You can enlarge the hole with a round file, or even coarse sandpaper and a lot of patience. The hole doesn't need to be perfectly enlarged. Just large enough for the sprocket to sit flush on your hub. Check out how others have done it with the coaster brake.

You can get an adapter like exseler and consider it an investment for a future build.

I gave you the advice above because you don't want to spend unnecessarily. That's all I can do. I give up.
 
Well, I said the adjustments were for parallel alignment, not centering. The centering was dead on since day one.

You can enlarge the hole with a round file, or even coarse sandpaper and a lot of patience. The hole doesn't need to be perfectly enlarged. Just large enough for the sprocket to sit flush on your hub. Check out how others have done it with the coaster brake.

You can get an adapter like exseler and consider it an investment for a future build.

I gave you the advice above because you don't want to spend unnecessarily. That's all I can do. I give up.
I didn't mean to criticise your advice, nor do I discount it.

Maybe the left-right alignment was the problem in my case too. When I put the sprocket on, I saw conflicting advice on which way to dish it. I decided to use with the teeth more inward (or right) because the person giving that advice seemed more authoritative than the other. The 2 sprockets seemed to be on the same plane when I was done. But how can you tell?
I used a straight edge as best as I could, but, as you know, the sprockets aren't positioned well for that test.

But I was rather suspicious of the rag joint from the beginning. I never was I00% satisfied with the centering.
I also may have had too much slack in the chain (which was taken up by the tensioner), and that may have been a problem.

In any case, I'd like to solve the chain-jump problem permanently. In car engines, sometimes timing chains have much more power going through them, and they stay on for an incredible number of turns.
Gates makes CarbonDrive cogged belt that I like (pedal side). I tried to buy the setup a few years ago, and their distributor failed me. Maybe they've improved their sales system since then. They require special sprockets, and I wouldn't know what was needed.

For now, I suppose the solution is a jackshaft kit, and a 3-speed internal rear hub.
It's a lot of money.
 

indian22

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Dec 31, 2014
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Nehmo I've just gone through both your threads and the advice given is solid so I'll address your stated original problem with the build. Bike threw chain, with included kit tensioner installed. It's a common problem for new comers to motorized bicycling, heck it's common wherever chain & sprocket technology is used, but on a kit bike setup 99% of the problem is due to improper setup/installation of the supplied kit parts. Unless you are really wanting the very real benefits of "shifting" which not only is expensive but also involves "correct" installation and setup, then the (almost) zero cost benefit of setting up the supplied kit parts correctly is the answer to your original problem.

A straight "chain line" from engine output sprocket to rear axle sprocket is essential and this is achieved during setup by making certain the engine is secured straight in the frame as well as properly secured to the frame. That done the sprocket is attached to the rear wheel. I haven't used a kit rag joint setup since I discovered the sprocket hub adaptors maybe 6 years ago, but using what you have will also work with narrow tires/wheels. I like to mount the sprocket with teeth as far away from the spokes as possible, to help the chain clear the rear tire.

Once both the rag joint/wheel & motor to frame are properly installed I loosely mount the rear wheel & center it. Then fit both pedal chain & drive chain for length. I usually don't get in a hurry to break the chains to length, but use a zip tie to hold them in place on the sprockets, while I check out the chain lines, just eyeball at this point for straight & by putting pressure on each chain with the hand to act as a tensioner check the chain to tie clearance as well. Chain rub on either side will eat a sidewall in no time.

The chain should be checked at the motor sprocket for correct seating, the rollers feeding smoothly and rollers completely settled down in the sprocket. If this is not the case the sprocket needs to be removed and both sides lightly thinned on both sides until the chain seats properly. I use an 80 grit flapper disc in an angle grinder for the thinning operation. Don't alter the height of the tips of the sprocket just the inside and outside of the sprocket and no lower than where the chain touches the sprocket. Very little material need be removed maybe 1/64" or so total. Chain will now run smooth as glass.

Chain length now needs to be addressed, both chains 'cause if they are flapping around they gonna rub And come off as well. 1/2" to 3/4" total deflection at mid chain is what I shoot for on both chains, this is where a quality tensioner comes in handy. I like the spring loaded tensioner that mount's on the motor cases best, as they absorb any minor inconsistency in the sprocket mounting concentric's. They can't get into the spokes either, like the kit units are prone to do when poorly fitted or maintained & that is a big safety concern.

I like the side to side adjustment of the 3 hole sprocket to hub adapter, it's a quality design that's so simple to install. Concentric and adjustable horizontally to help setup a straight chain line and or fit larger tire and wheels with chain clearance. If you run a coaster brake setup with the 3 hole sprocket make sure the sprocket has a very large center hole to clear the required modified brake arm lever as well. Well worth the money.

Of course all the above just brings us back to good installation and fitting the rear wheel with proper spacing has to be mentioned, having some axle spacers on hand is a part of this centering, truing & securing the wheel, while keeping chain lines straight and clearing both tires and chain stays and retaining proper chain tension on on both peal and motor drive sides.

You may be. well aware of all this information, Nemoh, but others may benefit from my poor (yet lengthy) explanations.

We can run but not hide from good installation practice. It's foundational. Best of luck. Rick C.
 

Chaz

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Jun 3, 2012
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Great information, Rick, and well written. I really like the idea of thinning the sprocket teeth. I have read about it on this forum before (possibly from you) but completely forgot about it. I haven't had a need to do it but will probably do it on a future build just to make it smoother and avoid problems.

Nehmo I would try the tooth thinning which might be just the ticket for your bike.

good luck
 
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indian22

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Thanks Chaz most of what I touched on has been addressed in posts by others on our various forums, but thought I'd gather these thoughts into one post. New kit builder's are often disappointed in their builds and certain aspects of kit components & I'm sensitive to this. Instructions are minimal at best and even Youtube videos are often lacking in any detailed information concerning the absolute minimum of basic knowledge to build a safe, working bike, let alone one that is enjoyable to ride. I identify with any builder that wants to understand why as well as how, but would caution new moto bike builders to get the first bike built & much riding & maintenance time invested before twisting off into adding more complex elements to their builds...especially if money, tools and mechanical experience is limited. I fear many motor bicycling enthusiasts are lost to the hobby before they understand how much fun it is to motor around on a dependable motor bike because they are left to do the first one their own way. I'm a mostly retired machine shop owner and many time certified welder who has built, modified and restored literally dozens of motorcycles, rods and custom cars over the last 60 years. Even so I spent a year researching how to correctly build a motorized bike with a China Girl before purchasing my first kit and still made some basic errors in that build which cost more dollars in parts and time than was necessary. It is still my favorite bike & has many hundreds of hours of riding time on her, but bears little resemblance to the original build, each part on the frame has been changed out several times as I tested and tried new things, but the basics described earlier once learned still remain. I'd hope to spare others that cost or perhaps even injury, but of course each builder is free to strike out on their own & perhaps it will work out just fine... Rick C.
 

Tommy Shields

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Mar 10, 2019
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I have the adapter from mzmiami........it's a great piece and I've got lots of miles on it with zero issues!! 5 thumbs up for this product! Seems like I got the sprocket (36t) from them as a package deal.......
Did your kit chain work or did youhave to replace the chain I want to use a 1” adaptor but they said stock chain would not work with the new sprocket
 
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Tommy Shields

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Nehmo I've just gone through both your threads and the advice given is solid so I'll address your stated original problem with the build. Bike threw chain, with included kit tensioner installed. It's a common problem for new comers to motorized bicycling, heck it's common wherever chain & sprocket technology is used, but on a kit bike setup 99% of the problem is due to improper setup/installation of the supplied kit parts. Unless you are really wanting the very real benefits of "shifting" which not only is expensive but also involves "correct" installation and setup, then the (almost) zero cost benefit of setting up the supplied kit parts correctly is the answer to your original problem.

A straight "chain line" from engine output sprocket to rear axle sprocket is essential and this is achieved during setup by making certain the engine is secured straight in the frame as well as properly secured to the frame. That done the sprocket is attached to the rear wheel. I haven't used a kit rag joint setup since I discovered the sprocket hub adaptors maybe 6 years ago, but using what you have will also work with narrow tires/wheels. I like to mount the sprocket with teeth as far away from the spokes as possible, to help the chain clear the rear tire.

Once both the rag joint/wheel & motor to frame are properly installed I loosely mount the rear wheel & center it. Then fit both pedal chain & drive chain for length. I usually don't get in a hurry to break the chains to length, but use a zip tie to hold them in place on the sprockets, while I check out the chain lines, just eyeball at this point for straight & by putting pressure on each chain with the hand to act as a tensioner check the chain to tie clearance as well. Chain rub on either side will eat a sidewall in no time.

The chain should be checked at the motor sprocket for correct seating, the rollers feeding smoothly and rollers completely settled down in the sprocket. If this is not the case the sprocket needs to be removed and both sides lightly thinned on both sides until the chain seats properly. I use an 80 grit flapper disc in an angle grinder for the thinning operation. Don't alter the height of the tips of the sprocket just the inside and outside of the sprocket and no lower than where the chain touches the sprocket. Very little material need be removed maybe 1/64" or so total. Chain will now run smooth as glass.

Chain length now needs to be addressed, both chains 'cause if they are flapping around they gonna rub And come off as well. 1/2" to 3/4" total deflection at mid chain is what I shoot for on both chains, this is where a quality tensioner comes in handy. I like the spring loaded tensioner that mount's on the motor cases best, as they absorb any minor inconsistency in the sprocket mounting concentric's. They can't get into the spokes either, like the kit units are prone to do when poorly fitted or maintained & that is a big safety concern.

I like the side to side adjustment of the 3 hole sprocket to hub adapter, it's a quality design that's so simple to install. Concentric and adjustable horizontally to help setup a straight chain line and or fit larger tire and wheels with chain clearance. If you run a coaster brake setup with the 3 hole sprocket make sure the sprocket has a very large center hole to clear the required modified brake arm lever as well. Well worth the money.

Of course all the above just brings us back to good installation and fitting the rear wheel with proper spacing has to be mentioned, having some axle spacers on hand is a part of this centering, truing & securing the wheel, while keeping chain lines straight and clearing both tires and chain stays and retaining proper chain tension on on both peal and motor drive sides.

You may be. well aware of all this information, Nemoh, but others may benefit from my poor (yet lengthy) explanations.

We can run but not hide from good installation practice. It's foundational. Best of luck. Rick C.
I want to use a hub adaptor also with matching sprocket and was wondering if my kit chain will fit the new sprocket or will I need to buy a new chain and if so will I have to replace the front sprocket to match the new chain
 
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indian22

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The kit chain & after market hub adapter/sprocket are the same pitch and will work together. (I suppose there could be an odd ball variety out there that I'm unaware of, but it would be an oddity indeed) The chains supplied in the kits are of "unknown quality" and I use the Diamond brand chains on most of my builds, of course it adds to the price of the build and there's that feeling of wasting a chain you've already paid for, but selecting quality is generally less expensive over time....

I'd caution against using an adapter/sprocket just because it's much cheaper, because the machine work & the resulting tolerances are typically poor. Read the preceding posts for more detail on this very important topic. Correctly building a good drive line will save you not only money, in the long run, but it will also improve the riding experience in general & your personal safety as well.

Have great fun with your build and enjoy riding often!

Rick C.
 
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Tommy Shields

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The kit chain & after market hub adapter/sprocket are the same pitch and will work together. (I suppose there could be an odd ball variety out there that I'm unaware of, but it would be an oddity indeed) The chains supplied in the kits are of "unknown quality" and I use the Diamond brand chains on most of my builds, of course it adds to the price of the build and there's that feeling of wasting a chain you've already paid for, but selecting quality is generally less expensive over time....

I'd caution against using an adapter/sprocket just because it's much cheaper, because the machine work & the resulting tolerances are typically poor. Read the preceding posts for more detail on this very important topic. Correctly building a good drive line will save you not only money, in the long run, but it will also improve the riding experience in general & your personal safety as well.

Have great fun with your build and enjoy riding often!

Rick C.
 

Tommy Shields

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Mar 10, 2019
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Indian thanks for the info after dealing with that aggravating sprocket that connects to the spokes I think the hub adapter would be a dream
 
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Tommy Shields

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Mar 10, 2019
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The kit chain & after market hub adapter/sprocket are the same pitch and will work together. (I suppose there could be an odd ball variety out there that I'm unaware of, but it would be an oddity indeed) The chains supplied in the kits are of "unknown quality" and I use the Diamond brand chains on most of my builds, of course it adds to the price of the build and there's that feeling of wasting a chain you've already paid for, but selecting quality is generally less expensive over time....

I'd caution against using an adapter/sprocket just because it's much cheaper, because the machine work & the resulting tolerances are typically poor. Read the preceding posts for more detail on this very important topic. Correctly building a good drive line will save you not only money, in the long run, but it will also improve the riding experience in general & your personal safety as well.

Have great fun with your build and enjoy riding often!

Rick C.
 

Tommy Shields

New Member
Mar 10, 2019
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In referring to a adaptor and sprocket I was talking about the two piece 3 hole set up you talked about before I’m new to this all my Terminology May not be correct. I’m trying to spend a little extra in new 12 gauge spokes, engine mount tensioner, and two piece 3 bolt hub and sprocket, getting new parts in is slowing down things but I want my first build to work and be safe it’s a two stroke and if all goes well I may try a four stroke next. I’m a heating and air repair man have much patients but am anxious to hear that baby fire for the first time.
 

indian22

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Tommy I remember my first couple of builds anticipating that first start.... & that's been more than 55 years ago; totally rebuilding and restoring a worn out and much ridden Cushman Eagle 8 hp scooter. Fortunately I had two expert engine mechanics and one fully equipped motor machine shop to help me bring it back to life and a paint and body shop to teach me to work the dings and kinks out of the sheet metal before paint was applied. I've been hooked ever since & motorcycles, cars and trucks by the dozens have followed. I built my first motor bike about 10 years past, as a lark, but had so much fun that I built a few more over the next 6 years, but mostly built motorcycles and off road vehicles. I really got into the board track style bikes about 5 years ago and now I only work on these little fellows...when I build at all.

Your terminology on the clamping hub adapter is fine, but understand that the two piece clamp, though the most common variety available, isn't the only style. I've found the. well machined two piece adapter works fine for most bikes that run basically stock power kit engines & that includes any so called bolt on aftermarket power/performance parts. When you start to modify the internals for big power increases...along with a "true" motorcycle expansion exhaust system the 2 piece hub adapter will slip and bend the wheel unless some alterations are made to both the hub and adapter. I've one bike with a 12.5 h.p. (factory rated) 5 speed 4 stroke that uses a 2 piece hub adapter & I've had no problems with it, but I made some mods and installed it as a permanent part of the hub.

The best hub adapter that I've used is the Sportsman Flyer 3 piece design & I have one mounted without mods on my most powerful build (quite a bit more than 12.5 h.p.) & it hasn't yet damaged my rear wheel. The adapter sprocket stand offs are also a bit longer and this helps if you're running slightly wider tires; to gain chain clearance and avoid tire to chain scrubbing. It's a more expensive setup but really well made. Remember that all the best drive line parts are wasted if not installed properly and with a perfectly straight chain line from engine to rear drive sprocket.

I like idler chain tensioners & especially the best spring tension units. Many disagree with me on this, but I use them. If I'm reading your post correctly it seems you are considering one that bolts to the motor and if that's the case (no pun intended), these are my favorites... for the China girl motor setups. The tensioners that bolt to the chain stays can loosen and get into the wheel with catastrophic, even fatal, results!

I'll post a couple of photos for you to consider before you buy.

Rick C.
 
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indian22

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0608170755.jpg 0605171632.jpg IMAG0018 2.JPG

Tommy these are just representative of what I've used on some of my bikes. The hub adapter shown is a 2 piece style used on a basically stock power kit motor & it works fine.

The tensioner is actually a repurposed part designed for motorcycle use...ebay has these, along with others listed under "motorcycle chain tensioners"...easy install, but can only use 3 bolts on the stock sprocket housing cover. 3 holds it quite securely and it matches all 3 holes pretty close, just have to enlarge the cover holes a bit.

Rick C.
 

zing

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View attachment 100412 View attachment 100413 View attachment 100414

Tommy these are just representative of what I've used on some of my bikes. The hub adapter shown is a 2 piece style used on a basically stock power kit motor & it works fine.

The tensioner is actually a repurposed part designed for motorcycle use...ebay has these, along with others listed under "motorcycle chain tensioners"...easy install, but can only use 3 bolts on the stock sprocket housing cover. 3 holds it quite securely and it matches all 3 holes pretty close, just have to enlarge the cover holes a bit.

Rick C.
Thank you for sharing the hub adapter and especially the photo of the tensioner mounted on the engine ! I would have mounted it on the chain stay in some fashion, but your work on that tensioner is awesome !!!
 
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