| | | Motorized Bicycle General Discussion Topics on bicycle engine kits, help articles, repair and modifications for your motorized bicycles | Can a sprocket be re-cut? Discussion at Motorized Bicycle Engine Kit Forum in the Motorized Bicycle General Discussion forum. Was wondering if anyone has ever had a sprocket re-cut. I have a moped hub that I want to ...  | | 
10-02-2009, 10:44 PM
|  | Motorized Bicycle Elite Member | | Join Date: Jul 2009 Location: Mi
Posts: 646
| | Can a sprocket be re-cut? Was wondering if anyone has ever had a sprocket re-cut. I have a moped hub that I want to use, it has a 44T and I'd like a 36T sprocket but I also want to use 24x3" Thick Brick tires. From my rough measurements any sprocket I use will have to have the offset that the original one has so the chain will clear the 3" tire and finding a replacement will be nearly impossible since I don't even know what this hub came off from.
Could I just take the sprocket to a machine shop and have them cut it down to a 36T? | 
10-03-2009, 05:22 PM
|  | LORD VADER Moderator | | Join Date: Jan 2008 Location: pampa texas
Posts: 2,095
| | Re: Can a sprocket be re-cut? probably could but I'll bet it won't be cheap or you could find a bike that has the right number of teeth on the front crank a lot of bikes front cranks will work for a rear driven engine sprocket plus you can make it off set with washers lot of ways to do different size rear sprockets. some sprockets already have an off set just got to do some looking.
Last edited by Norman : 10-03-2009 at 05:24 PM.
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10-03-2009, 05:34 PM
|  | Motorized Bicycle Elite Member | | Join Date: Aug 2009 Location: orange county, ca
Posts: 553
| | Re: Can a sprocket be re-cut? look for a BMX sprocket. a lot of them are solid, so you can drill your own holes, and i know some of them have an offset. if not, or the offset's not enough, like norm said, shim it. you could probably go to a metals dealer, find a scrap piece of solid aluminum rod a little smaller than your sprocket, and have them slice you a piece the thickness you need. (or ask jim. doesn't sound like he's too busy, he could make you one...) | 
10-03-2009, 05:42 PM
|  | Motorized Bicycle Elite Member | | Join Date: Jul 2009 Location: Mi
Posts: 646
| | Re: Can a sprocket be re-cut? Already asked Jim via PM but he never responded, chalked it up to him having too much on his plate already. | 
10-03-2009, 05:51 PM
|  | Motorized Bicycle Elite Member | | Join Date: Aug 2009 Location: orange county, ca
Posts: 553
| | Re: Can a sprocket be re-cut? | 
10-03-2009, 06:38 PM
|  | MANIC Mechanic | | Join Date: Sep 2008 Location: Clearwater, FL
Posts: 1,122
| | Re: Can a sprocket be re-cut? Kevlarr,
Sorry about that...Somehow I missed the pop-up that you had sent a PM.
A 44T has an outside diameter of 7.29" A 36T has an O.D. of 6.015"
I can't really tell for sure from the pictures, but it looks like it may be close. Lay a 5 1/2"" diameter circle on your existing sprocket to see if the re-cut would end up in the dished area...If not I can re-cut it for $15.00. Clamp it...indicate it...call-up tool #2 and done!
Jim | 
10-03-2009, 07:58 PM
|  | Motorized Bicycle Elite Member | | Join Date: Jul 2009 Location: Mi
Posts: 646
| | Re: Can a sprocket be re-cut? Tanks Jim, I'll do that Monday. Got all the parts stashed at work in the shop at the moment. lol | 
10-03-2009, 08:21 PM
|  | Motorized Bicycle Elite Member | | Join Date: Oct 2008 Location: Urbandale Ia
Posts: 497
| | Re: Can a sprocket be re-cut? Kevlarr, Im not sure what you are trying to do, but if you are just wanting to change your gear ratio, your 24 x 3 tire will be slightly taller than a 26 x 2, so the 44 tooth might work fine for you.
The bike I am building now has 24 x 3 tires on it and they are taller than any of my 26 inch tires.
Just a thought.
John | 
11-03-2009, 10:18 PM
|  | Motorized Bicycle Elite Member | | Join Date: Jul 2009 Location: Mi
Posts: 646
| | Re: Can a sprocket be re-cut? Quote:
Originally Posted by bairdco | Thanks for the link bairdco, just got the sprocket and it was a perfect fit only problem is it ended up being a 38 not a 36 as the seller described but after looking at it closely I don't think you could get a 36 and have the offset.
There would be no way to re-cut the original because 5 1/2" ends up being inside the slots on the sprocket.
Hub fits pretty well too. Test fitted it on an old MB frame that may or may not end up being the starting point for my BT build. A little grinding on the dropout and some widening of the chainstays with a 2x4 it drops right in.  | 
11-04-2009, 01:12 AM
| | Motorized Bicycle Elite Member | | Join Date: May 2009 Location: colorado
Posts: 488
| | Re: Can a sprocket be re-cut? To pay a programmer at 45$ an hour to even figure the math out is way out out of our costs when compared to a sprocket precut/machined from china or indonesia. Its our death as a manufacturing country. | | Thread Tools | | | | Display Modes | Linear Mode |
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