is it possible to turn a bmx stunt bike into a multi geaar bike using mountain bike parts?

Question

i just like to tinker with the bike, its the fastest it can go right now and i use a local bike trail and in the city it is easier to manage and a lot more responsive than any other type of bike.. people on mountain bikes are surprised i can keep up with them unless they really try. biggest gear i can fit on front, smallest cog on back, no pegs. i have a junked mtb, bent rims, brake cables are shot so im just seeing if any of the parts are useable. i would only make it a 6 speed though using the biggest of the front gears, and all the rear for more top end speed.

Answer 1

Why!!!!!!!!!!!!!!

Answer 2

If the bike has a steel frame, you MIGHT be able to bend the rear triangle out enough to accommodate a 130mm or 135mm wide MTB hub, but you will have to keep the rear triangle aligned Vertically, Horizontally and in terms of the angle of dropouts in relation to each other. Most likely it will take more force and skill than most tinkerers would be willing to try.
If you overcome that major hurdle, I might recommend something like the Shimano Nexus 7 or 8 speed internally geared hub (130mm spacing) since you most likely have horizontal dropouts, which would allow you to adjust chain tension by moving the wheel back or forward. This will prevent you from needing to jimmy rig some type of derailleur hanger setup as well!

Hope that helps!

Answer 3

Not only would you have to tinker with the rear spacing, but you'd also have to figure out a way to route the shifter cables to the front and rear derrileurs. Not impossible, but cumbersome. An internal shifting hub would be the best option because otherwise you'd have to figure out how to mount a rear derraileur. You would also have all kinds of tinkering to do with the chainline. (A wider bottom-bracket to account for the wider spacing?)

It's a nifty idea, and maybe a fun project, but to be honest I kind of like the idea of a BMX-er tearing it up on singletrack. You could even get a flip-flop hub for your rear wheel which would give you another gearing option as well as the chance to make it a fixed-gear- that could be fun, too!

Answer 4

sure, you'd have to spread the rear dropouts, mtb hubs are wider to allow for the extra cogs. this could be a problem depending on the construction of the bike.

and you'd need one of those clamp-on derailer hangers like cheap bikes have.

but why bother?

Answer 5

Its much easier to get a kids sized bike with 20"wheels and all the mountain bike bits fitted and then modify to suit what you want to do(bars, stem, seatpost, pedals, etc.)