Length of mech cage

[Spudalumps]

Hey all! My wife's little sister's, boyfriend.. young lad he is 19 shreds his Carrera like its nobody's business constantly ripping mech hangers and mechs alike. I truly have no concerns fixing his bike because its awesome to see him thrashing it! I have replaced his M370 twice, ive noticed the tolerances on them are terrible im wondering if this is why they're falling to pieces?

theres a nice XT mech on ebay thats a short cage im pretty sure his is currently normal defo not short cage? whats the effect of cage length?

Kind regards,

J

 

[hamster]

Cage length allows it to wrap more chain, so dealing with bigger tooth count differences in the gear range. A shorter cage gives better ground / damage clearance.
It's argued that short cage mechs shift better and have less chance of dropping the chain, but that's probably solved by clutch mechs anyway.

 

[benjabbi]

As above.
Assuming it has a triple ring you might find that in the granny ring and the smaller cogs the mech can't take up enough chain and it's baggy. Not really a problem you probably will not find yourself in those gears anyway. Total capacity needed is found by adding the difference in front chainrings to the difference in rear sprockets. So for example 42/32/22 has a 20t difference and an 11-28 cassette has a 17t difference. The mech needs a capacity of 37t to take up the chain properly in all gears.

 

[stevet1]

Could you ss it?

 

[Spudalumps]

As above.
Assuming it has a triple ring you might find that in the granny ring and the smaller cogs the mech can't take up enough chain and it's baggy. Not really a problem you probably will not find yourself in those gears anyway. Total capacity needed is found by adding the difference in front chainrings to the difference in rear sprockets. So for example 42/32/22 has a 20t difference and an 11-28 cassette has a 17t difference. The mech needs a capacity of 37t to take up the chain properly in all gears.

Took a while for me to understand but once I wrapped my head around it its very clear thank you!