Cassette guard nessecity?

markemark

Well-Known Member
A cassette guard on a Raleigh ebike has snapped and come off. It was hooked into the spokes.
Is it worth replacing ?
 

SydZ

Active Member
Location
Scotland
Their purpose in life it to prevent the chain going into the spokes due to folk that don’t have a clue on how to set up the stops on the rear derailleur.

I’ve taken them off all my bikes and never had an issue.
 
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Jody

Guru
So long as you're comfortable with skidding at an inopportune moment.

Personally, I don't like or have them on my bikes. But you can still send the mech into the spokes, so be warned.
 
Location
London
I've seen that happen to 3 riders... It can be very costly!

A plastic disc isn't going to help prevent that, so set your rear mech endstops properly.
Might a plastic disk not help at all?
Or at least, with the noise, tell you pronto that something is wrong before it gets worse?

I did once take two spokes out after I bashed an ultegra mech on a park post years ago, but the ultegra mech survived and is still going strong on another bike - damn fine mechs.

My Ridgeback expedition bike (definitely not a BSO) came with one fitted, and having a lot of faith in Ridgeback I decided that they were a good idea - so I bought 2 or 3 from Planet X but gave up on efforts to fit them to some of my other bikes after my feeble brain couldn't figure out how to do it with their spoke patterns.

I can't help but think that they can do little harm, only good - I don't share the contempt for them in some circles that @Cycleops notes.

advice: If anyone's bike ever falls over on the mech side, check things before riding - I once stopped spoke wheel damage on another bike by doing this.
 

Venod

Eh up
Location
Yorkshire
But where does it end ?
A guard on the frame to protect it chance you overshoot the smallest cog.
A guard to stop the chain coming of the front mech at either extremity
Call me old fashioned, but I prefer to set my gears correctly so they don't overshoot.
I always take the discs off if fitted, and never consider fitting one if I build a wheel.
 
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Vantage

Carbon fibre... LMAO!!!
Their purpose in life it to prevent the chain going into the spokes due you folk that don’t have a clue on how to set up the stops on the rear derailleur.

I’ve taken them off all my bikes and never had an issue.
I can't help but feel your answer is particularly rude.
you folk that don’t have a clue on how to set up the stops on the rear derailleur
I suppose you were born with the knowledge to repair your bike?
For the rest of us, we had to learn those skills, many a time through trial and error over time. Some folk are also just not mechanicaly minded.
You folk that can't answer a question without being smug about it should learn to try it.
 

ColinJ

Puzzle game developer
Might a plastic disk not help at all?
Or at least, with the noise, tell you pronto that something is wrong before it gets worse?
I suppose it depends on how big the protective disk(disc?) is and where the mech makes contact. In all 3 cases I witnessed, the end of the derailleur contacted the spokes in the position 'B' in the example picture below. A plastic plate extending only as far as 'A' wouldn't have helped.

608076


The results in each case were: wrecked mech, broken derailleur hanger***, broken chain, and several broken spokes producing a horribly wobbly wheel.


*** Catastrophic frame damage if the bike in such an incident doesn't have a sacrificial hanger!
 

ColinJ

Puzzle game developer
Thinking about it more though... :whistle:

The spokes are much nearer to the derailleur at 'A' than at 'B', or at least - they should be. In that case, the disk should/might help. Maybe the derailleurs of the stricken bikes had been bent inwards at point 'B' in the kind of way that you suggested here...

advice: If anyone's bike ever falls over on the mech side, check things before riding - I once stopped spoke wheel damage on another bike by doing this.
 
OP
M

markemark

Well-Known Member
Ok so I understand indexing and the concept of the limiting screws. The gears are nicely indexed so stop properly at the largest cog. How do I know where the limiting screw stops it at as when in first gear I can’t change to below that to know the limiting screw kicks in?
 

ColinJ

Puzzle game developer
Ok so I understand indexing and the concept of the limiting screws. The gears are nicely indexed so stop properly at the largest cog. How do I know where the limiting screw stops it at as when in first gear I can’t change to below that to know the limiting screw kicks in?
I over-adjust it until I can't select that gear then back it off just enough to allow me to.
 
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