Bicycle Mechanics - Detachable Chainrings?

Right, so I'm bored this summer, and from my 7 bikes, I have quite a few parts leftover. My plan is to take my old Trek 4300 frame and turn it into a commuter/town bike. I'm thinking singlespeed at the momemt, or at least only one ring up front. I have a set of like crappy Alivio cranks but it seems the rings are machined together or something. Is it possible to separate these rings ? If not, is there a tool other than a hand file for which I could file down the outer ring and turn it into a bashguard of some sort?

Also, I kinda wanted just one brake (for simplicity and weight). it will be a v brake, but should it be front or rear? My gut says front as it would be more powerful, but what do you guys think?

One last thing, If I use one chainring up front, and say a 7 speed freewheel in the back, will my chain really wear down quickly or should I be okay, assuming I don't shift often to the high and low cogs?

Sorry if there are some typos,

Byron

I see no advantage whatsoever to removing either chainirng. Take off the front derailleur and shifter, if you must, then use the inner chainring, with the outer as a guard and potential downhill gear. You can always stop and manually rethread the chain onto the other chainring, as plenty of cyclists did in the old days.

Likewise, I strongly believe it is absolute folly to remove either brake, particularly for a commuting bike to be ridden in traffic. If you must have only one brake, make it the front, but reconsider your idea. On dry roads, I generally use the front brake almost exclusively, but I prefer to use the rear for gradual slowing on long descents, to avoid overheating the front rim, tyre, or brake pads. On wet roads, I find that I need to use both brakes together to avoid skidding; a front wheel skid is nasty business!

Thanks for the advice, I may do the front and rear brakes as it would be nice for the modulation. As for leaving the outer ring on, I may consider your idea, I just didn't like having my pants cut up.

You can dremel (sp?) the teeth off the outer ring. I ran a 7 speed with one ring in the front and found the chainring wore out really fast and the chain begin to slip. As a broke student I flipped it and used a hammer to flatten the teeth back. As for brakes, I have both on my geared and fixed bike. I like the idea of having the back brake in an emergency situation.

I would not if you are referring to a double reduction to single.
Your chainline will be off.
A triple with a chainring middle, bashguard outer.
A dremel would take WAY too many bits\long- grinder.

The problem with 3\1 mid IS you can usually only get say 39-40 teeth ring mounted as the mid ring sits close to the frame.

A 7 cluster- to mid chainring runs fine.

oooops..I'm a mtb'er. Don't know if this will help. :rolleyes:

Photo: Mid mounted 39 t ring on triple spyder\ hand ground 46 t ring bashguard.

Also- No ramped rings for single front.

>jef.

If the problem is simply that you're cutting up your pant cuffs, have you considered just mounting a cheap plastic chainring guard for commuting?

I made my big ring into a chain guard by snapping off the teeth. I just adjusted a Crescent wrench to grab them then bent them off one at a time. Then I cleaned it up with a file. It really took very little time.

I made my big ring into a chain guard by snapping off the teeth. I just adjusted a Crescent wrench to grab them then bent them off one at a time. Then I cleaned it up with a file. It really took very little time.

Took me 15 min mounted grinder. 2 cm off the wheel. Yes I should have clipped the teeth.