Bike Forums - gas engine?

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Quote:

Originally Posted by HillRider (Post 19207054)

Well, among the "old and crabby" are most state's DMV's that consider motorized bicycles, particularly those with gas engines, a motorcycle and subject to the same licensing, registration, driver's license endorsements, etc.

It depends on where you are. Some US states don't allow them but many police still see it as a matter generally not worth their time unless the rider is being very silly and the police officer has little else to do.

Quote:

Also, most states are old and crabby enough to forbid motorized bicycles on MUPS.

Yea, but,,, again, it depends a lot on the rider's behavior.

Really however--the more I've read, I'm tending to believe that OP won't find anything suitable in a bicycle engine--either gas or electric.

The best bet is a BIG front hub motor, with a big capacity battery. And that ain't going to be lightweight, or cheap.

Quote:

Originally Posted by wphamilton (Post 19207090)

Not experience, but I've looked into also and have a couple of observations.

Using a small gasoline engine makes practical sense since it's cheaper, and a gas tank carries a lot more energy than a battery. However, the cheap 40-50 cc engines have a reputation of wearing out quickly so I think it's a false economy. The noise and heat are drawbacks. Engineering it is a little tricky because you have to mount it somehow down around your feet, and it seems to me that there's not a lot of room there if you want to retain comfortable pedaling, with pedal assist being pretty much out of the question, and finally I have to wonder if most bike frames are going to handle the vibrations long term.

In short, it appears to be a short term novelty modification. In fact, if you read message boards where people have done this, the guys bragging about the durability have gone 400-600 miles. I don't know about those folks, but 500 miles is a month's worth of riding for a cyclist, so that's not really a good application. So, personally, I've never really been tempted by the idea.

it was a VERY short term novelty, the gas engine idea is long since discarded. I'm going to rebuild the drivetrain with MTB components,with a lowest hillclimbing gear of 22 front ring/34 rear cog this winter, with future possibilities of a hub drive in place of the current single front wheel or a mid drive like the bafang running thru the MTB components to the single rear wheel driving wheel. yes, it is not only boat anchor heavy but it drives from only the right rear wheel

Quote:

Originally Posted by Slash5 (Post 19134013)

Check your state laws. Here, adding a gasoline engine to a bike makes it a non-compliant vehicle that cannot be used on public roads.

I talked to the folks that control the local MUPs, i was told gas engines are a no no on the trails even if not in use, but electrics are ok because I'm disabled. as I've said before i have no intention of using any electric assist i might add for anything other than climbing the hill to get home after leaving the MUP

Quote:

Originally Posted by keg61 (Post 19220087)

Trike? I like that idea and the front drive would be super easy if it's a normal size wheel. I'd want to add a faring to cut down the power required at higher speeds.

Quote:

Originally Posted by wphamilton (Post 19220418)

Trike? I like that idea and the front drive would be super easy if it's a normal size wheel. I'd want to add a faring to cut down the power required at higher speeds.

high speed has never been an issue, i don't expect it will be in the future. it currently has a 20" front wheel which i was thinking of changing the fork and wheel out for 26" but the consensus seems to be I should stay with 20" because the smaller wheel will provide better torque. I weigh 350 pounds, the trike as is weighs 100+the reason for this project is to be able to get up the hill out of the river valley, where the bike paths are, to home

I would be concerned about having sufficient weight over the front wheel when going uphill in order to have sufficient traction to pull 450+ lbs.

Quote:

Originally Posted by keg61 (Post 19220459)

Yep I think that's wise and I'm sure I've seen some 20" hub motor wheels. I don't know how economical that is compared to something in the drive train.