Just finished the final touches of my China girl two stroke 60cc mounted to a generic mountain bike with Shimano gears and brakes. I intentionally got a 52 teeth rear gear to mount w/ the motor's gear drive to give me a better pulling power during acceleration noting that my 260lbs body frame would certainly need just that. And it has worked well. Since I really don't speed on the bike, I am not bothered by the lower top speed. It just cruises at 25mph with the engine sounding just right. I must also include the fact that I use standard road bicycle tires (not the balloon tires commonly partnered with MBs) with tire pressure of up to 45psi. (the tire inscription says max of 60lbs.) to lighten the load. My real concern is that with the present configuration, my shimano gear set is rendered inutile. I learned that w/ an installed jack shaft, I could at least shift gears from the rear. This would mean I could increase my max speed and even lower the load on the motor by shifting to higher gear when traveling uphill. Some of you might have some experience already on using jack shafts. What are the advantages and disadvantages compared with an ordinary single gear rear drive? Not to mention, the jack shaft would cost me probably the same as buying a new motor. Is it worthwhile? Thanks for your comments.
rear drive versus jack shafted front drive
- Thread starter bikebloak
- Start date
You would have to downshift to go faster up hill. And like you said, if you have a jackshaft, it will allow you to go faster up hills, and faster on flats. But it all depends on your setup. I have a 32T sprocket, live in a fairly flat area, and see no reason to get a jack shaft. If you live in area with lots of hills, and then lots of flats too, then a jackshaft would help you. My bike tops out at 34-35 MPH depending on weather conditions.
For me these bikes are more of a toy, and a hobby, and are not my main means of travel. So I don't see a reason to spend that much money on it. Id rather ride it till it explodes and just buy a new engine.
For me these bikes are more of a toy, and a hobby, and are not my main means of travel. So I don't see a reason to spend that much money on it. Id rather ride it till it explodes and just buy a new engine.
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Ultimately true what you said. After your reply, I'd say I'll delay the idea of a jackshaft and run my engine down first. The real reason why I got the engine was so that I could run the bike on pedal power for exercise the first 5 miles and in case I get tired I could motor my way back home without getting myself too tired. Such a lame excuse really!!! Hey, it's so much fun and a cheap mode of recreation!!! Especially at a time when I am so prone to depression. Million thanks geoldr for setting back myself to perspective.
we run our bikes with no jackshaft type setup, just the chain going from the trans to the rear hub and have no issues or problems, more chains and gears is just more problems, keep it simple
I totally agree with the points above. I'm a big fan on keeping it simple. Where I live there are some dirt roads and pretty good sized hills. My bike is used to take me into town five miles away and then from place to place once I'm in town. I pretty much need a jack shaft. So I am using a mountain bike, China two stroke and a jack shaft. I love it and it does really well. Although I would really like a single speed chopper bike with the standard chain drive. It just wouldn't get me back and forth to town very well. With my current set up I can do a little over 30mph on the flats and 15mph up any hill. I think the best little "to and around town" bike for me would be a Worksman Classic Cruiser with a springer fork, three speed spindle, a four stroke engine and front and rear drums. That is just too much $$$ for me right now though. Just the bike would cost the same amount of money that I have into my entire set-up.
Cruiser Heavy Duty Bicycles - Design Your Own by Worksman Cycles
Cruiser Heavy Duty Bicycles - Design Your Own by Worksman Cycles
To shift kit or not to shift kit? that is the question. I personally think they are worth every penny spent. They make the ride a lot more fun. They also of course make it more complicated. More maintenance intensive as well but not excessively so. If used properly the engine will last longer since the RPM's will drop. Just make sure not to be in too high a gear when starting out. Anyway you can't really tell anyone if they are worth it or not unless you try it yourself.
Yeah, it all depends on what you need and what you use it for. I don't need a shift kit, I have a motorcycle for travel along with a car, the motorized bike is just something fun to mess with on the weekends. I dunno. It's true that you won't know until you try it out somewhere. Or buy one
For me the MB is a daily commuter for work, and weekend fun as well. I'm running a straight chain-to-hub on a 36T sprocket, and I'll be the first to admit it's not the best hill-climber but if I pedal along with it and run through the gears I get there. I may add a jack shaft kit later, but for now it's great.
Smooth tires will help, there's more drag from knobbies (and vibration) and though I prefer the extra grip the latter gives me I'll probably try smooth tires on another build.
What I'm wondering about is why the bike's gears aren't working for you? On mine, I still have all 21 available, on my second build we put wide cranks on it and lost the front 3, but it's still a 7-speed after that.
Smooth tires will help, there's more drag from knobbies (and vibration) and though I prefer the extra grip the latter gives me I'll probably try smooth tires on another build.
What I'm wondering about is why the bike's gears aren't working for you? On mine, I still have all 21 available, on my second build we put wide cranks on it and lost the front 3, but it's still a 7-speed after that.
