The newb kid on the block

[2CycleLogicalIssueS]

A quick Hi to everyone, I've been lurking around here in the shadows for a few months now, getting to know the place.
I've put together a few "HT" powered bikes for friends, myself and a few for customers so far. Just last week I made a simple friction drive with a little baby weed wacker engine, not sure of the CCs but it barely has enough power to pull the skin off a custard, let alone move me along, I have to pedal it up to speed, then it will motor me along on the flats, but it will not accelerate without me pedaling, I'm pretty sure its geared wrong (drive roller to big)
Oh, before I forget, Im in NSW, Australia.
Cheers, Chris........

 

[2CycleLogicalIssueS]

A quick hi to everyone , I've neen lurking in the shadows here for the past few months, getting to know the place and its people. I have so far put together a few HT powerd bikes for myself, friends and a few paid builds.
A few days ago I threw a lil baby weed wacker engine on a bike for meself, but it barely has the power to move me along, I have to pedal it up to speed, then it will motor me along, but it will not accelerate unless I am pedaling it. methinks it needs a smaller drive roller
Anyhow its back to reading the forums for some more edumacating for me........
Oh by the way, I'm Chris and I'm in Australia...

 

[loquin]

Welcome, Chris.

Take a look at the 'FAQ' in the friction drive forum. It should help. A weed whacker motor, especially one of the tiny ones, would probably need a roller not larger than 1 inch in diameter, and possibly not larger than 3/4 inch.

I wrote a power calculator that can give you an idea as to how much power is needed to maintain speed on a motorized bike. A 25cc or smaller engine is probably good for no more than 1 HP, and possibly less. A friction drive efficiency can vary widely - if it is aligned properly, used with slick tires, and tires with a low rolling friction, is very efficient - approximately 95% efficient! However, if it is used with knobby tires, or with a very small drive roller, is misaligned, or used with low air-pressure in the drive tire, the efficiency can drop substantially. I would estimate that it could be less than 70%, if all these factors are present.

 

[2CycleLogicalIssueS]

splitpostonalities???

I might have "cyclelogicalissues", but split personalities??
Not that I am aware of?
I thought I messed up my first post, so I rewrote it only to find that indeed it went through after all
Anyhow, thanks for the welcome Loquin, and appreciate the link provided!
I've taken the lil wacker off the back and planning "front wheel belt drive"
I have attached a 20inch outer rim to a 26inch front wheel using pieces of 415 chain link!
I dismantled the chain and using the outer links hacksawed a slot in one end to slot onto the spoke then the other end of the link is then bolted to the empty spoke hole of the 20 inch drive ring......Super simple, true, and rock solid....
I could have done it without cutting a slot and just unscrewed the spokes and slid the link straight on the spokes, but I never could true a wheel!!! Now I just need to mount z engine, buy a belt and Robert's ya mothers brother... ..
But........I cant take the credit for the drive ring idea.........it was a few year old 2 line post I stumbled upon in my lurkings this morning