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Old 05-12-2011, 02:58 AM
bubruins bubruins is offline
Motorized Bicycle Newbie
Join Date: May 2011
Location: Middle TN
Posts: 1
Default Potential (fast) Road Bike build

Hello all,

As an avid cyclist and an avid gearhead it was only a matter of time until I tried to fit an engine to a bike frame, especially when engine kits are as inexpensive as they are now.

I had a friend call up and say that he wanted to sell his used 49cc eBay engine kit with all parts (I've actually ridden this setup on a $80 mountain bike host). The awesome thing is he only wants $40 for everything.

Another friend called up within the same week and he has a $80 Raleigh road bike for sale that has 700c's, good cranks, gear system, and good brakes, and some really neat little vintage parts. I'm thinking put one and two together here.

As any other addicted gearhead would do - I've already told both that I'm going to be buying their parts as soon as I can meet them. What I have to do now is figure out if I can make these two work or if I'll need to find a different host.

In total here are the parts I'm thinking about using:
Raleigh road bike frameset (531 steel tubing, 54cm frame)
700c wheelset (mallard hubs, no name rims)
700x23c tires (110-130psi)
6 speed rear cassette, 42/52 chainrings
downtube friction shifters
straight bar
cross levers (pretty effective stopping my friends fixed gear w/ standard road bike brake caliper)

There is a decent chance that I'd swap in my 4340 Schwinn World Sport frame instead and make the 531 Renyolds frame my new fixed gear. It's getting harder and harder to outrun my hipster "fixie" friends while in full fixed gear urban assault mode (soon to be brakeless, too).

I've searched Google and this forum and have found very little about putting an engine on road bike host. One post said that he had to space the rear of the frame to fit the sprocket. Other than that I have not seen much (other than obviously fitting new bars that will accept a twist throttle).

I'd consider myself to be pretty fit as I like to do 20-30 mile rides on my Peugeot at a 14-16mph pace in hilly Nashville, TN. The motor/bike combo would be a kicks and giggles thing more than anything. I know it won't be greenway legal, but I imagine that if I adjusted the gearing 40mph on flats could be attainable with engine power and my own physical input (this would require the pretty 68 tooth chainring that has been hiding behind the glass at my LBS as well as a different sprocket for the engine to wheel transition). Any advice about doing a build like this would be very useful.

Last edited by bubruins; 05-12-2011 at 03:09 AM.
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