A few questions about modern XT

[paulwakinshaw]

Hi People

I'm a little confused with some of the options I have when buying modern XT for my Marin refresh project I wonder If you can help?

1: M770 front mech - top swing, what are the pro's/con's of top swing or is it for a particular application?

2:M771 rear mech - my options are long cage SGS and medium cage GS - what is all that about? pro's/con's too

TIA - Wako

 

[legrandefromage]

There are no pros and cons as such. You buy the front mech to suit the frame cable routing and chainset ring size.

rear mechs depend on the size of cassette etc and so-on

 

[tintin40]

2:M771 rear mech - my options are long cage SGS and medium cage GS - what is all that about? pro's/con's too

TIA - Wako

long cage means you can choose a wider range of gears that a short cage wont be happy with eg big chain ring big sprocket.

 

[paulwakinshaw]

2:M771 rear mech - my options are long cage SGS and medium cage GS - what is all that about? pro's/con's too

TIA - Wako

long cage means you can choose a wider range of gears that a short cage wont be happy with eg big chain ring big sprocket.

Cool - so long cage it is then. The front mech can be either top or bottom pull, but my frame is set up for bottom pull.

If i just run the normal M770 chain set with 22, 32, 44 will the top swing mech be ok?

 

[RobMac]

Shimano say : The short rear mech, the GS cage should be used with single and double chainsets only.
And the long SGS should be used with triple chainsets.

 

[RobMac]

Sorry got mixed up there thought you were on about the rear
rapid rise mechs ooops.


My touring bike was fitted with one, it meant that used the little lever
to go up the way and the big lever to go down the way. Basicaly the
opposite to the normal function, felt blooming odd to use I changed
to the normal rear mech, now Im happy

 

[FluffyChicken]

1: M770 front mech - top swing, what are the pro's/con's of top swing or is it for a particular application?

The one in the middle, if it will fit on your frame you can use it. Its main benefit in my eyes is for top-pull use as you do not have the length of cable moving away from the seat tube to the mech, causing a place for things to snag in. so using a top swing means the cable goes behind the seattube instead.
But none of that is important to you as you are bottom pull

So it's really down to if it will fit on your frame, if you have an ovalised tube at the bottom you pretty much have to use the other conventional version. But you may get away with it.

P.S. This is modern talk and should be in Off-topic chat


.

 

[paulwakinshaw]

top banana!

Thanks all. Mods - please move this if required

Wako

 

[Anthony]

I'm a little confused with some of the options I have when buying modern XT for my Marin refresh project I wonder If you can help?

1: M770 front mech - top swing, what are the pro's/con's of top swing or is it for a particular application?

You could fit a conventional-swing, but you would probably be best to fit a top-swing, bottom-pull. Top-swing is the modern standard and although conventional-swing (i.e., high-band) is still used, it's generally only where it's necessary - e.g., where a rear suspension pivot or shock mounting point would be in the way of the low band of a top-swing fm.

 

[MikeD]

Given the option I'd go for conventional rather than top-swing - IME they seem to last longer before the pivots go all baggy. But often you don't have the option