Will this combo work for a 11.2 mile commute?

[cdevidal]

* 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?

 

[Alaskavan]

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.

 

[cdevidal]

1) I presume the Cannondale would be a multi-geared bike. You shouldn't have to pedal "like crazy" to go 20mph.

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.

2) How reliable does the system need to be? How are your mechanical skills? The Happy Time motors are (IMO) not famous for reliability.

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?

 

[cdevidal]

2.) Would 25mph be too fast to pedal assist?

I found this thread which answered my second question. Helps when you know what to search for
http://www.motoredbikes.com/showthread.php?t=13283&page=3

Anyone know on the first question?

 

[cdevidal]

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.

 

[RedBaronX]

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.

 

[cdevidal]

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?

According to this thread, it can be done:
http://www.motoredbikes.com/showthread.php?t=13283&page=3

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:
http://www.sheldonbrown.com/gears/

 

[Alaskavan]

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

 

[skrufryder]

* 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

 

[cdevidal]

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

OK thanks!