Will this combo work for a 11.2 mile commute?

Discussion in 'Travelling, Commuting & Safety' started by cdevidal, Sep 19, 2010.

  1. cdevidal

    cdevidal New Member

    * I only have $500 budgeted for bike and motor.
    * I'm going 11.2 miles to work each way. Flat roads, some traffic.
    * I need to be able to cruise at least 20mph.
    * I will be mounting panniers on the back.
    * I weigh 235lbs, so I want to pedal assist to get in shape.
    * Total weight: rider + bags + lunch + rain gear + change of clothes + shoes + 7lb knee brace, around 275lbs (guessing).
    * I want the engine/bike combo to be rather reliable.

    I'm thinking: Decent Cannondale (or similar) road bike off Craigslist, plus Zoom Bicycles' 49cc kit $130 (chain drive). ZB seems to have a good rep.

    Two questions:
    1.) Won't I require different gearing for pedal assist so my legs aren't spinning like crazy?
    2.) Would you recommend a different combo of bike+motor? Would you say $500 is too low for what I need to do, reliably?

  2. Alaskavan

    Alaskavan Guest

    1) I presume the Cannondale would be a multi-geared bike. You shouldn't have to pedal "like crazy" to go 20mph.
    2) How reliable does the system need to be? How are your mechanical skills? The Happy Time motors are (IMO) not famous for reliability.
  3. cdevidal

    cdevidal New Member

    Yep, multi-speed bike.

    I think I'll be able to get up to 25mph given the weight load and a good straightaway. Supposed to be able to do 30+ with a light rider, level ground and proper gearing.

    Moderate skills, I could probably rebuild a motor like that if I had instructions and enough patience :)

    So now I have two more questions:
    1.) What usually fails on these motors?
    2.) Would 25mph be too fast to pedal assist?
  4. cdevidal

    cdevidal New Member

    I found this thread which answered my second question. Helps when you know what to search for :)

    Anyone know on the first question?
  5. cdevidal

    cdevidal New Member

    I found that a 56 tooth chainring (from eBay) at $45, and an 11 tooth sprocket in a cassette ($??) with 26" tires and an 80rpm cadence will let me keep assisting about 30mph. I'm guessing I'll need to spend about $100 on an upgrade like this.

    If Happy Time motors aren't a good durable choice, what are some other choices which may reach my price range? Now ~$400 for bike and motor.
  6. RedBaronX

    RedBaronX Member

    my bike is a 7 speed, and I can pretty much motor faster than I can pedal. Since it is working with two drive chains (motor and pedals) won't one always go faster and be working harder than the other?

    You could always pedal when you feel like it with the engine off, and then engage the motor on the fly whenever you feel like it.

    I had planned to do that myself, but my bike turned out to be so heavy (about 80 lbs) that pedaling it is kinda brutal.
  7. cdevidal

    cdevidal New Member

    According to this thread, it can be done:

    Think of it as lifting some weight off the gas engine's load. But the "meat" gearing needs to be high enough (big chainring in the front, tiny sprocket in the back) or else like you said, one will always go faster. Once they get close, you're both pushing the same brick through the air.

    Sheldon Brown's gear calculator is handy:
  8. Alaskavan

    Alaskavan Guest

    What usually fails on the HT motors? Read through the section of the forum related to 20Stroke Engines.
  9. skrufryder

    skrufryder Member

    * I weigh 235lbs, so I want to pedal assist to get in shape.

    If you wana get in shape why dont you just peddle and forget about the motor......good diet and daily excersize is the best way
  10. cdevidal

    cdevidal New Member

    OK thanks!
  11. cdevidal

    cdevidal New Member

    I would love to, but at that distance and my speed, I can't justify the extra time it would take out of my day. A moto bike is the perfect combination.
  12. Hawaii_Ed

    Hawaii_Ed Member

    Should be fine depending on the conditions....I would not be happy at 20 MPH for my commute, but that would only be 30 mins for you at that speed :)
  13. wbuttry

    wbuttry Member

    i found on my bike it dont matter how much you pedal on flat ground with the motor on it will pull you at idle mine does and im 200 plus myself i got the red bat motor on my bike and a old schwin cruiser that what it take to hold my big but oh buy the way you dont want a little seat either trust me the bumps are harder going faster than a pedal i got one of the svhwin wide seats like a riding lawn mower has and it is comfortable it is a foot wide 2 in thick and 6 in front to back

    Last edited: Dec 3, 2010
  14. DuctTapedGoat

    DuctTapedGoat Member

    500 bucks would do you up a sick bike.

    Remember this - you can take a 600 dollar off the wall 26" bike, or you can go to a thrift shop and spend less than 26$ on a 26" bike. When you put a 48cc motor in either frame, you're going to get about the same performance. I've built off 400$ Schwinns, and 5$ Huffys - same speeds, same things vibrate loose, same things need to be maintained, just a different paint job.

    Just make sure you get as large a frame as you can comfortably ride. This will keep the gas tank out of your crotch when you stand at a stop. Seriously, don't worry about the gearing system right now. For now, build it, note the performance, and then make modifications after that. You're going to have to pedal to take off no matter what, so don't worry about not being able to keep up pedaling. If you want the little exercise a motorized bike offers, keep it in the highest gear all the time so you're working yourself on the takeoffs. With your weight I can almost guarantee you the spokes won't hold up. When I was 230 I was breaking rims ever 2-3 months. Since, I've dropped to 180, and it makes a big difference in the spoke stress. Last thing on this would be that unless you're planning on pedaling 4 MPH, don't worry about ever changing gears. Max it out and ride - it'll keep up. If you don't like it - upgrade later, but only when you feel that after evaluating your build it is necessary.

    As well, the motor is 20-25 pounds, so add that to your calcs.

    For your budget, I would invest in alternate sprocket installation styles for your motor side drive chain and a nice seat. Also, get some portable tools that'll fit every nut and bolt on the bike for any emergency repairs and maintenance you'll need to be doing. Those motors vibrate like crazy, and loosen things up a lot. Another thing to consider upgrading at initial build is your gastank size - you won't regret it ever. If you have money left over, get extra exhaust gaskets, extra friction clutch pads, and a spare gastank cap (the ears can slip out and shoot 50 yards away never to be seen again). One thing I haven't regretted is going with solid tires. With a 30 mile a day habit, the rear tire lasts 9 months or so, and they cost me less than 30 bucks a piece, and it's a whole new world changing a flat on a MxB. You can't flip it upside down and you have two chains and sprockets to deal with. To test this, try and change your current non motored bike without flipping it upside down, even try looking in a mirror to do it, cause that's about how fun it's gonna be every time.

    So - to paraphrase.

    Biggest (in total frame and wheel size, not diameter) and cheapest bike.
    Alternate rear wheel configuration for drivechain sprocket.
    Solid tires.
    Portable tools for emergency repairs.
    Larger gas tank.
    Extra: Gas cap, Clutch pads, Exhaust gaskets.
  15. Slackbiker

    Slackbiker Member

    One of the things I like about friction drive is that the tire reduces the noise and vibration somewhat. Mainly I like the stealth aspects, I put a pack cover over the motor, and it looks like an odd tour bike. Most motorized bikes look like motorcycles. Occasionally I need to peddle along the very wide shoulder of the Interstate (which is legal for a bike in many areas out West, dozens of cops have seen me, one has stopped, just out of curiousity). Or I want to use bike paths, and sure I could be obvious with a "motorcycle", but i'd rather not. My motorized bike is a peddle-assist bike. I peddle most of the time. I've even went on group bike rides, or travelled with tour bicyclists. If you want a "motorcycle" and almost never want to peddle then going with a chain or belt drive is probably best for long term efficiency.
  16. loquin

    loquin Active Member

    cdevidal, you don't say where you're located, but depending on the location a friction drive, high quality kit like Staton's or BMP with a honda or r/s engine may be just the ticket.
  17. happycheapskate

    happycheapskate Active Member

    re: what fails. When people fail to put enough oil in the gas mix, they burn up the rings or shear a piston. When people drive them wide-open-throttle all the time, they don't hold up as long.

    If you keep it oiled and keep using fuel filters, it will probalby do fine, and you can still get the motors for $100-200.

    If you get a BMP rear rack drive, you can get motors with pull starts that look like big weeder engines, probably longer lasting.

    If you are using a aluminum bike, that is probably the way to go. The China Time will probably vibrate your frame apart.