Road bike questions

You (respective posters) seem to be extremely knowledgeable about this topic so I would like to pick at your brains a little bit if I may.
Some of you may have already done this or currently still have the availability to do this so indulge me.

The only thing I hear is that this is possible on a 26" Mountain bike. I have little desire to be on a mountain bike so is it possible to do it on a 27" road bike? I do not see how anything would be impossible personally. It would still mount and the engine would run regardless. The chain and etc could be modified in length to fit.

Furthermore, after the engine is mounted and works properly on a bike, and the top speed is 30 MPH, whats not to get a smaller sprocket and change the gear ratio to increase speed. Granted the wear on the clutch would be greater as well as the rest. With higher gears chances are that the engine would need to be started or engaged at higher speeds in order to perform well within the functional range. Is the largest factor the safety factor? The lack of desire to go in excess of 30 MPH? Or is there something I have gotten wrong that inhibits the speed. Perhaps torque?

Please let me know. This has been waging war on my mind for the better part of a week now.

Thanks.

hi inkstrom and welcome; i think there would no problem with a motor on a 27". sure you can change gears. the question about speed has always been, how much money you want to invest. there are builds here using polini engines the other end might be a weedeater scrubber bike. the world is at your feet. mitch

Thank you for welcoming me

What rules out a road bike as opposed to a mountain bike?

Road bike will go faster on 44 tooth set up 30mph for sure.Down side tires less tolerant of stickers
[goat heads] less rubber to pad the bumps rims are easier to bend in my opinon. There are people using these and I never have heard them complain though.

i thought about building a fast road bike but the frame doesnt look very tolerant of extra stress. also no front suspension. maybe a 700c commuter bike with straight bars would be a good option.

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"You must cultivate the feeling that a warrior needs nothing"-don juan

Road bikes are built to be lighter than cruisers and mountain bikes so the frames are generally weaker and this is not good when you stick a 10 pound 5 to 10 thousand rpm vibrating motor on the frame. Vibrations on to light a structure is bound to break it. Lets say you get a stronger than normal road frame the skinny tires absorb less shock and will flatspot easier and are less stable than the fatter tires used on most motorized bikes. The taller wheel is also weaker as there is more leverage at the longer distance from hub to tire. (basically is a longer lever and bends easier) You can use tandem rims and 48 spoke wheels to help here and a 37 mm tire will help with the too skinny problem. So basically you are creating extra problems to solve but they are solvable. I see no advantage to using a road bike except if it is all you have access to.

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LennyHarp of Lenny's Bikes & Things
http://lennyharp.net
The true value of a man is not judged by what he has, but rather by what he can do without.
"We are what we repeatedly do. Excellence, then, is not an action, but a habit." -- Aristotle

I built one with a road bike and it was the bee's knees fo'sho'!

The wheels and frames may look thin and weak, but I've never had one crack like my cruiser frame did.

The ultimate limiting factor of top speed on these chinese engine kits is wind resistance. They make about 2-3 horse power. Rolling resistance isn't that great, but wind resistance is squared for each addtional 10 mph.

That an if you rev one much beyond 7000 rpm, it will explode.

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If it ain't broke, and you mess with it long enough, it will be.

A triangulated structure is stronger per pound than a bendy-twisty-curvy cruiser type frame any day.

Otherwise buildings and airplanes would be bendy-twisty-curvy.

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If it ain't broke, and you mess with it long enough, it will be.

I guess you got one of the thicker tubing road bike frames. Touring and cross bikes do use a heavy gage tube usually. Road bikes are made with lighter gage tubing and are generally not as strong as a heavier gage tubing bike even if it is a cantilever frame. Cruisers are the weaker design but use enough extra tube to make up for it usually. A diamond frame Mountain Bike is by far the strongest frame to use and that is what I have been saying since I joined the motorized bike forums. I have raced road bikes down mountain roads at 60 miles an hour, I have built bike frames from tube sets, so I know a little about this , and I would not recommend a road bike frame over a mountain bike or cruiser without solving the issues I pointed out. It is irresponsible to encourage someone to build a flimsy motorized bicycle in my opinion.

__________________
LennyHarp of Lenny's Bikes & Things
http://lennyharp.net
The true value of a man is not judged by what he has, but rather by what he can do without.
"We are what we repeatedly do. Excellence, then, is not an action, but a habit." -- Aristotle

Mine rides nice with a 40 t sprocket

Smooth roads are best

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