Rear sprocket

A place to discuss the repair, design, and customization of the bicycle itself, not the powertrain ( battery, controller, motor, etc ).
diesel.mechanic04   100 µW

100 µW
Posts: 8
Joined: Sep 07 2021 11:21am

Rear sprocket

Post by diesel.mechanic04 » Sep 07 2021 11:30am

I have am having issues destroying inners of the rear freewheel/sprocket set. I am running a Sick bike parts style jackshaft kit with an 66cc 2-stroke. I destroyed the inners of the last one in about 75 miles. This seems to be a mostly electric forum, but I was refered here by SBP because they couldn't answer my questions. Is anyone else having this problem?

User avatar
Chalo   100 GW

100 GW
Posts: 9082
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Rear sprocket

Post by Chalo » Sep 07 2021 11:37am

diesel.mechanic04 wrote:
Sep 07 2021 11:30am
I have am having issues destroying inners of the rear freewheel/sprocket set. I am running a Sick bike parts style jackshaft kit with an 66cc 2-stroke. I destroyed the inners of the last one in about 75 miles. This seems to be a mostly electric forum, but I was refered here by SBP because they couldn't answer my questions. Is anyone else having this problem?
Are you talking about a multi-speed cassette or a multi-speed freewheel, or something else? By "inners", do you mean the freewheel ratchet? The inboard sprockets? Something inside the hub?

There are things you can do to improve what you've got, but we have to understand what the problem is. Tell us what you know about your bike. Pictures can be very helpful.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

markz   100 GW

100 GW
Posts: 11947
Joined: Jan 09 2014 11:38pm

Re: Rear sprocket

Post by markz » Sep 07 2021 12:40pm

Is the rear gear a Sick Bike Parts part or a brand name part like Shimano, Sunrace, DNP?
Could be a defective part, could be that it was installed wrong.

SBP makes a crank freewheel or shall I say rebrands a chinese part as their own custom made part, like what Luna Cycle does.

diesel.mechanic04   100 µW

100 µW
Posts: 8
Joined: Sep 07 2021 11:21am

Re: Rear sprocket

Post by diesel.mechanic04 » Sep 07 2021 5:30pm

Chalo wrote:
Sep 07 2021 11:37am
diesel.mechanic04 wrote:
Sep 07 2021 11:30am
I have am having issues destroying inners of the rear freewheel/sprocket set. I am running a Sick bike parts style jackshaft kit with an 66cc 2-stroke. I destroyed the inners of the last one in about 75 miles. This seems to be a mostly electric forum, but I was refered here by SBP because they couldn't answer my questions. Is anyone else having this problem?
Are you talking about a multi-speed cassette or a multi-speed freewheel, or something else? By "inners", do you mean the freewheel ratchet? The inboard sprockets? Something inside the hub?

There are things you can do to improve what you've got, but we have to understand what the problem is. Tell us what you know about your bike. Pictures can be very helpful.
It is a multi speed freewheel. By inners I mean the pawl inside the freewheel breaks or jams so that it catches instead of spinning free. I have replaced the parts more than 5 times. Unfortunately, I don't have any pictures of the broken parts.
I'm not shifting under power (learned that lesson)
The last freewheel was a cheap one from Amazon because Ive broken so many I'm nervous about buying and breaking so many.

Hummina Shadeeba   10 MW

10 MW
Posts: 2163
Joined: Apr 25 2014 10:26pm
Location: sausalito cali..up the hill in front of the cruising club.

Re: Rear sprocket

Post by Hummina Shadeeba » Sep 07 2021 5:35pm

A 66cc two stroke likely can put out way more torque than a bicycle freehub ratchet is intended for. you can get a steel freehub body from DT swiss.
Last edited by Hummina Shadeeba on Sep 07 2021 5:42pm, edited 1 time in total.

diesel.mechanic04   100 µW

100 µW
Posts: 8
Joined: Sep 07 2021 11:21am

Re: Rear sprocket

Post by diesel.mechanic04 » Sep 07 2021 5:38pm

markz wrote:
Sep 07 2021 12:40pm
Is the rear gear a Sick Bike Parts part or a brand name part like Shimano, Sunrace, DNP?
Could be a defective part, could be that it was installed wrong.

SBP makes a crank freewheel or shall I say rebrands a chinese part as their own custom made part, like what Luna Cycle does.
I don't know what they are. I pulled most of them off of random old bikes. I know some of them were sunrace. None of them were from SBP.
I have had extensive conversation with SBP about the issue, and they have never seen it happen with any freewheel and don't know what I tell me.
I can't imagine it's installed wrong since it just screws on. And I have had the same issue with wheels taken from other bikes even when I didn't remove the sprocket.

Hummina Shadeeba   10 MW

10 MW
Posts: 2163
Joined: Apr 25 2014 10:26pm
Location: sausalito cali..up the hill in front of the cruising club.

Re: Rear sprocket

Post by Hummina Shadeeba » Sep 07 2021 5:43pm

youre saying the pawls or ratchet inside is breaking right? sounds like an old style screw on freewheel and not the newer cassette freehub style. was told the dt swiss steel freehub is the best bet. or with electric could do a fixed gear in the back and no ratchets to break and also then can use a regen brake.

diesel.mechanic04   100 µW

100 µW
Posts: 8
Joined: Sep 07 2021 11:21am

Re: Rear sprocket

Post by diesel.mechanic04 » Sep 07 2021 7:47pm

Hummina Shadeeba wrote:
Sep 07 2021 5:35pm
A 66cc two stroke likely can put out way more torque than a bicycle freehub ratchet is intended for. you can get a steel freehub body from DT swiss.
I would tend to agree with that. I did find it interesting that SBP has never heard of it happening with their kit that is made for this application.

diesel.mechanic04   100 µW

100 µW
Posts: 8
Joined: Sep 07 2021 11:21am

Re: Rear sprocket

Post by diesel.mechanic04 » Sep 07 2021 7:49pm

Hummina Shadeeba wrote:
Sep 07 2021 5:43pm
youre saying the pawls or ratchet inside is breaking right? sounds like an old style screw on freewheel and not the newer cassette freehub style. was told the dt swiss steel freehub is the best bet. or with electric could do a fixed gear in the back and no ratchets to break and also then can use a regen brake.
Yes. It is the screw on freewheel. SBP said they heard them to be better than the cassettes and they have never had one break.

Hummina Shadeeba   10 MW

10 MW
Posts: 2163
Joined: Apr 25 2014 10:26pm
Location: sausalito cali..up the hill in front of the cruising club.

Re: Rear sprocket

Post by Hummina Shadeeba » Sep 07 2021 8:12pm

is it their fancier white industries one? maybe that's what you need. i have one. i have a different use than you and really i'll almost never use the ratchet aspect and i removed all the springs that push the pawls and its now virtually silent. still will engage but not all pawls at once. just the ones that happen to hang by gravity. good enough for me but sounds like you need the pawls to all work

User avatar
Chalo   100 GW

100 GW
Posts: 9082
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Rear sprocket

Post by Chalo » Sep 07 2021 8:14pm

diesel.mechanic04 wrote:
Sep 07 2021 5:30pm
It is a multi speed freewheel. By inners I mean the pawl inside the freewheel breaks or jams so that it catches instead of spinning free. I have replaced the parts more than 5 times.
You're putting superhuman power and torque through the freewheel, so you need to get better than minimum quality parts. If you can't find an e-bike specific unit like Sunrace MFE30, then at least get a Shimano branded one.

Old ('80s and earlier) Suntour freewheels are way more robust than the run of the mill these days, but the remover tool is weak and janky and will ruin your day when you have to take the thing off.

You can consider advice to use this or that cassette hub, but those start out with a handicap, because the ratchets are at a smaller diameter than freewheels. Good ones are very expensive, and I don't trust that they're stronger than freewheels because of the size disadvantage.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

Hummina Shadeeba   10 MW

10 MW
Posts: 2163
Joined: Apr 25 2014 10:26pm
Location: sausalito cali..up the hill in front of the cruising club.

Re: Rear sprocket

Post by Hummina Shadeeba » Sep 07 2021 8:27pm

Chalo wrote:
Sep 07 2021 8:14pm




You can consider advice to use this or that cassette hub, but those start out with a handicap, because the ratchets are at a smaller diameter than freewheels. Good ones are very expensive, and I don't trust that they're stronger than freewheels because of the size disadvantage.
inside the white industries freehub it only has three pawls. this one has 6 at least. hoping for the best when i put it together. maybe the aluminum can be hardened or the spring strengthened to further lodge the pawl https://www.ebay.com/itm/234074790074?_ ... %3A2334524

User avatar
Chalo   100 GW

100 GW
Posts: 9082
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Rear sprocket

Post by Chalo » Sep 07 2021 8:39pm

Hummina Shadeeba wrote:
Sep 07 2021 8:27pm
inside the white industries freehub it only has three pawls. this one has 6 at least. hoping for the best when i put it together. maybe the aluminum can be hardened or the spring strengthened to further lodge the pawl
Because nothing is perfectly precise or perfectly stiff, it doesn't really matter how many pawls you have. One or two of them will take all the load every time. Extra pawls are a good selling point, but no real benefit. And they add noise and friction.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

diesel.mechanic04   100 µW

100 µW
Posts: 8
Joined: Sep 07 2021 11:21am

Re: Rear sprocket

Post by diesel.mechanic04 » Sep 07 2021 10:09pm

Hummina Shadeeba wrote:
Sep 07 2021 8:12pm
is it their fancier white industries one? maybe that's what you need. i have one. i have a different use than you and really i'll almost never use the ratchet aspect and i removed all the springs that push the pawls and its now virtually silent. still will engage but not all pawls at once. just the ones that happen to hang by gravity. good enough for me but sounds like you need the pawls to all work
He said all but one of his are from Walmart brand bikes.

User avatar
socrace   10 mW

10 mW
Posts: 26
Joined: Nov 16 2019 2:42pm
Location: Illinois

Re: Rear sprocket

Post by socrace » Sep 07 2021 11:01pm

Uneven idle speed and dragging clutch can slam the freewheel back and forth and destroy the freewheel pawls pretty quick, especially with centrifugal clutch, but maybe lever type also. Might be able to see it when idling.
Walmart Schwinn 700c hybrid, ebikeling 1.5kw dd, rclipo 24s, ebay $50 controller, CA3.1

markz   100 GW

100 GW
Posts: 11947
Joined: Jan 09 2014 11:38pm

Re: Rear sprocket

Post by markz » Sep 07 2021 11:17pm

So you pulled the rear sprocket off old random bikes and you wonder why they are failing without going out and buying a brand new Shimano rear sprocket or a Sunrace ebike specific rear sprocket as Chalo mentioned.

diesel.mechanic04   100 µW

100 µW
Posts: 8
Joined: Sep 07 2021 11:21am

Re: Rear sprocket

Post by diesel.mechanic04 » Sep 08 2021 8:28am

markz wrote:
Sep 07 2021 11:17pm
So you pulled the rear sprocket off old random bikes and you wonder why they are failing without going out and buying a brand new Shimano rear sprocket or a Sunrace ebike specific rear sprocket as Chalo mentioned.
I have done both. Besides, SBP says they use walmart freewheels. I have destroyed sunrace freewheels just the same as all the others.

User avatar
Chalo   100 GW

100 GW
Posts: 9082
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Rear sprocket

Post by Chalo » Sep 08 2021 10:38am

diesel.mechanic04 wrote:
Sep 08 2021 8:28am
markz wrote:
Sep 07 2021 11:17pm
So you pulled the rear sprocket off old random bikes and you wonder why they are failing without going out and buying a brand new Shimano rear sprocket or a Sunrace ebike specific rear sprocket as Chalo mentioned.
I have done both. Besides, SBP says they use walmart freewheels. I have destroyed sunrace freewheels just the same as all the others.
Most Sunrace freewheels are cheap junk. They're better than Falcon or DNP, but that's not saying much. The e-bike freewheels are a different thing, and they do cost more.

If there's something about your system that's hammering the freewheel pawls, there may not be a satisfactory solution for you that uses bike parts. But ordinary bicycle freewheels are known to tolerate 300 lbs-ft of steady torque, and other folks seem to be able to use the SBP shift kit with reasonable reliability (at least compared to those terribly unreliable stinky gas motors). Try to figure out what your motor system might be doing to wreck freewheels, because if the result is the same with both decent and trashy freewheels, then it's not a freewheel problem.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

vernonbain   1 µW

1 µW
Posts: 3
Joined: Sep 05 2021 11:31pm
Location: Australia
Contact:

Re: Rear sprocket

Post by vernonbain » Sep 08 2021 9:03pm

A 66cc two-stroke engine is certainly capable of producing far more torque than a bicycle freehub ratchet is designed to handle. A steel freehub body is available from DT Swiss.
11 Verrell St, Wetherill Park, NSW 2164, Australia
Website: https://www.kayaks2fish.com/sydney/doub ... em-kayaks/

User avatar
Chalo   100 GW

100 GW
Posts: 9082
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Rear sprocket

Post by Chalo » Sep 08 2021 9:53pm

vernonbain wrote:
Sep 08 2021 9:03pm
A 66cc two-stroke engine is certainly capable of producing far more torque than a bicycle freehub ratchet is designed to handle.
That's entirely dependent on the reduction gear ratio. But it's true that a freehub will give out sooner than a freewheel of equal quality and material, just because it's smaller and subject to higher forces.

One question for the OP to consider... There are two freewheels in a SBP shift kit setup. One on the jackshaft, and one on the rear hub. If the single freewheel on the jackshaft is holding up, but the rear multi-speed freewheel isn't, it's worth considering what is the difference between the two? Is there a big reduction ratio between them? Quality difference? Bad chainline to one but not the other?
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

diesel.mechanic04   100 µW

100 µW
Posts: 8
Joined: Sep 07 2021 11:21am

Re: Rear sprocket

Post by diesel.mechanic04 » Sep 09 2021 6:57pm

Chalo wrote:
Sep 08 2021 9:53pm
vernonbain wrote:
Sep 08 2021 9:03pm
A 66cc two-stroke engine is certainly capable of producing far more torque than a bicycle freehub ratchet is designed to handle.
That's entirely dependent on the reduction gear ratio. But it's true that a freehub will give out sooner than a freewheel of equal quality and material, just because it's smaller and subject to higher forces.

One question for the OP to consider... There are two freewheels in a SBP shift kit setup. One on the jackshaft, and one on the rear hub. If the single freewheel on the jackshaft is holding up, but the rear multi-speed freewheel isn't, it's worth considering what is the difference between the two? Is there a big reduction ratio between them? Quality difference? Bad chainline to one but not the other?
Good point. I had considered that. I did have the front one go out one time, but that was after several hundred miles of riding. Also the front one only engages when you pedal or start the engine where the rear engages whenever you are on the throttle.

Hummina Shadeeba   10 MW

10 MW
Posts: 2163
Joined: Apr 25 2014 10:26pm
Location: sausalito cali..up the hill in front of the cruising club.

Re: Rear sprocket

Post by Hummina Shadeeba » Sep 14 2021 2:31pm

The freewheeling cranks’ ratchets are almost unused and the motor just spins through.

Hummina Shadeeba   10 MW

10 MW
Posts: 2163
Joined: Apr 25 2014 10:26pm
Location: sausalito cali..up the hill in front of the cruising club.

Re: Rear sprocket

Post by Hummina Shadeeba » Sep 16 2021 8:57pm

Took the springs out and it spins silent but can get a pawl or two to engage by banging it if I need to.
Drilled and threaded for a coming aluminum pulley.
Attachments
EBB271C2-5B6F-43B8-936E-89BA236C28CB.jpeg
EBB271C2-5B6F-43B8-936E-89BA236C28CB.jpeg (2.89 MiB) Viewed 65 times

LewTwo   100 kW

100 kW
Posts: 1453
Joined: Apr 08 2014 4:46pm
Location: Houston, Texas
Contact:

Re: Rear sprocket

Post by LewTwo » Sep 17 2021 7:08am

A thought:
Does anyone make a roller clutch based rear hub (other than the Shimano Allfine 8 speed IGH).
The more I learn the more obvious the immensity of my ignorance becomes.
Weight Wennie E-Bike https://endless-sphere.com/forums/viewt ... 3#p1173723
Shaft Drive Grocery Getter https://endless-sphere.com/forums/viewt ... =6&t=90718
...and thanks to Justin!

Hummina Shadeeba   10 MW

10 MW
Posts: 2163
Joined: Apr 25 2014 10:26pm
Location: sausalito cali..up the hill in front of the cruising club.

Re: Rear sprocket

Post by Hummina Shadeeba » Sep 17 2021 9:35am

If looking for a durable clutch the dt star clutch is supposedly pretty durable.

I’ve found on my freehubs the ratchets don’t catch at the same time and wish I’d sprung for the dt. Eventually I’ll get unlucky in essentially cassette roulette and will only engage one ratchet tooth and see what happens

Post Reply