Removing rear derailleur - can front derailleur still function?

[grellboy]

Fixed my lad's bike multiple times but now rear derailleur is knackered - gone sort of saggy instead of being taut - so just wondered in the interim before replacing it - if I removed the rear d and then some links in the chain, would it still be possible to change through the three rings using the front d? Or would there not be enough slack in the chain due to the lack of the rear d for this to be possible? I. E. Does removing the rear d effectively turn the bike into a single speed?

 

[Amanda P]

You need the rear derailleur if you're going to keep using the triple at the front.

As you move the chain from a big ring to a little one, there'll be lots of slack chain that isn't wrapped around the chainring any more. That'll flap about and more than likely get dragged down between the rear wheel and the chain stay, or with the lack of tension in the chain, drop off beyond the smaller chainrings and down behind the chainset altogether.

But if you shorten the chain so that there's no slack when it's on the smallest chainring, there won't be enough chain to use either of the bigger ones.

You could run it as a single speed - although even that could be problematic.

Perhaps the spring in the rear derailleur is broken? You may be able to replace it, or NHS-issue derailleurs are cheap as chips on ebay - like this one.

 

[Cycleops]

A pic would be useful. Might not be the rear mech at all.

 

[Ajax Bay]

No. Just replace it. Would take ten minutes max (assumes chain with split link).

 

[Smokin Joe]

This. TBH it would be easier (or just as easy) to replace it than it would be to shorten the chain. And RD's are remarkably cheap.

That said, not everyone agrees with the common wisdom that the chain must be under permanent tension. You could go for a "floating chain"
View attachment 370731

Chains a bit......................














































..................never mind.

 

[Globalti]

Are you sure the derailleur spring has gone slack or is it simply that the top run of the chain hangs loose when you back-pedal? If the latter, it's because the freehub is sticking.