5 Speed Derailleur

Riatsala
Riatsala Posts: 44
edited March 2009 in The workshop
Can anyone help, I'd like a to build a commuter using only a rear deraileur. Everyone I speak to tells me I'll still need a guide on the front chainset. Is there someway to avoid this? In my youth everyone had five speed racers, why is this no longer possible?

Comments

  • roger_merriman
    roger_merriman Posts: 6,165
    sounds like bunk, plenty of new bikes with a single chainring, hub gears, fixed etc.... though the chain line i guess if far enought could come off, i don't think so though.
  • wgwarburton
    wgwarburton Posts: 1,863
    Riatsala wrote:
    Can anyone help, I'd like a to build a commuter using only a rear deraileur. Everyone I speak to tells me I'll still need a guide on the front chainset. Is there someway to avoid this? In my youth everyone had five speed racers, why is this no longer possible?

    The only issue I can foresee is that modern chains are more flexible and tend to shift more easily, so in theory it might be more likely that the chain will derail from the chainring.
    In practise, however, I can't see this being an issue- if chains were prone to unshipping like this then you'd get random, unexpected shifts, which clearly doesn't happen until things start to wear out.

    Try it & see. The worst that can happen is that you need to fit a font mech to stabilise the chain, but I seriously doubt that'll be necessary.

    Cheers,
    W.
  • wgwarburton
    wgwarburton Posts: 1,863
    Hi,
    Following up- saw two bikes today with exactly this setup- one was fairly "new" and looked like exactly the sort of thing you are planning (single-shifter commuter bike), the other an old '70s 5-speed with a cottered steel chainset.

    Cheers,
    W.
  • nation
    nation Posts: 609
    Some single chainring cyclocross bikes have "jumpstops" fitted (it's just a little plate on a band mount) to keep the chain from jumping towards the cranks, and a guard ring fitted to keep the chain from jumping outwards. I really, really doubt it would be necessary on a bike used for commuting.

    In fact, if memory serves Edinburgh Bicycle Couriers have a single chainring and a rear derailleur without any kind of chain guide.