Rear Sprocket Hub Adapter question

[Daedric_Angel]

I haven't been around lately but I was considering getting a Hub adapter sprocket set to replace the standard rubber and mess of bolts. The kit I have on my bike is a 66/80 on a beach cruiser style bike & the kit said it has a 44 tooth sprocket. I want to note that I am a big buy and it does well aside from the steeper hills in my subdivision. So my question is this. Should I go to a higher tooth for more torque? or Get another 44 and focus on upgrades for the extra torque? I have not added anything major to the build. I did add an exhaust with expansion chamber but that's all.




You can see my previous post about the build here: https://motoredbikes.com/threads/first-build-progress.55239/#post-493701

 

[Tyler6357]

Get the sprocket adapter for sure, you can get different sprockets and try them to see which one can handle the hills in your area best.

 

[YetiWoodz]

I'm a tall guy, I weigh 200 lbs. There's small hills I go up but they aren't bad, I haven't gone under 3500 rpm uphill and I never need to pedal. I have a similar setup as you. I have a 38T sprocket. I tried the 44T because it came with my kit, but I had extra low end torque that I wanted to trade off for more top speed. I like my 38T better, I think its the perfect one for me. Going down 6 teeth wasn't a huge dramatic difference, I noticed more top end from jetting down from a #70 to #65 because I was running rich. The jetting added about 500rpm and I think I can go down even further to get even more power.

 

[YetiWoodz]

Also, these sprockets (I'm not talking about the size) are the most common when you search on amazon.

Each one of those I got, it was slightly bent and the center hole need to be grinded a little or else it won't go on correctly. But its not hard to do. Just hammer it flat and use a dremel tool or file to grind.

 

[RB55]

Hub adapters, if mounted correctly, are a permanent solution to the rag joint spoke mount that comes with the kit. HOWEVER they do have to potential to destroy your wheel if mounted incorrectly! My bike is out of service and will be for a few days since my hub adapter wasn't fully clamping down on the hub, leading it to slip and completely destroy the rear wheel's spokes which led to a nasty flat tire. Had to order a new rear wheel, inner tube, rim tape, and freewheel. Bad! Cost me about $100 for everything. I did a lot of research yesterday about slipping hub adapters yesterday and this is what I found:

1. Use brake cleaner or other powerful degreasers to clean the hub mount and hub before you mount everything up.
2. File down the adapter halves (not the circular part but where the bolts meet) so the adapter will tighten around the hub instead of tightening down on itself.
3. Use blue threadlocker on all bolts or they will come loose easily
4. Use the maximum torque you possibly can to tighten the bolts. I have a small metal pipe I can use with my allen keys to get practically unlimited torque. The bolts that come with the mount are extremely strong, you will break you back tightening them before you strip them out.
5. This tip actually comes from @Karl Snarl . I'm using retaining compound (Loctite 660) on the adapter to prevent any possible slippage. The compound is actually made to prevent bearings/gears from slipping on a rotating axle, so I think it would be perfect for this application. However, once it sets, I doubt you will ever be able to remove it from your hub without disassembling the entire wheel and heating it with a blowtorch. In the end it's up to you but for me I will always be using my bike as a motorized bicycle so it's not an issue.

As for your sprocket, I would recommend a 38T like @YetiWoodz or a 40T if you really want more torque. I only weigh 125 so for me even a 36T gets me up very steep hills at 30mph or so. However for someone heavier with a stock engine a 38T or 40T is the best option. A smaller rear sprocket will not only help you go faster on flats but also will significantly reduce engine vibrations and reduce wear on the engine by decreasing your RPMs. For me a 44T (especially since I'm light) had my engine revving at 9,000 or 10,000 RPMs at full throttle all the time (measured by tachometer). Once I put a 38T I was down to 7000 RPM at full throttle.