full sus and front ...
 

[Closed] full sus and front dérailleur dilemma.

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Hi there could anybody help me out with this problem,new to full suspension type bikes but brought a commencal super 4 frame and was hoping to use alot of the components off my hard tail frame brakes crank derailleurs ect, most well fit ok but not sure about about my front shimano m971 duel pull front derailleur as it seems to fit high up the seat tube and would look as if it would fowl the suspension linkage?
is this the case or do i need to change to a m970? the cable run is a bottom pull feed under the crank case of the frame and up to the mech from that route.
can anyone advise me on this cheers


 
Posted : 27/01/2012 12:13 pm
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personally, I'd look for pics of complete bikes on google and go for top swing or bottom swing based on what's fitted to the ones you see.


 
Posted : 27/01/2012 12:14 pm
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This any help?
[img] [/img]

2009 frame


 
Posted : 27/01/2012 12:19 pm
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Normally I'd expect the issue to be a matter choosing between [url= http://www.chainreactioncycles.com/Models.aspx?ModelID=20685 ]conventional[/url] or [url= http://www.chainreactioncycles.com/Models.aspx?ModelID=20684 ]top swing[/url] mech's as top swing mech's tend to be fitted where there limited space due to suspension (as per my single pivot bikes). Though looking at google images for the Super 4, they come equipped with conventional front mech's, so it doesn't look to be an issue with the Commencal. To test if it's going to foul anything, after fitting the mech in the position it needs to be to work correctly, just let all the air out of your shock and see if anything clashes with the mech....
For what it's worth in my limited experience top swing mech's tend to be rubbish, and I'd much prefer to fit a conventional if possible.


 
Posted : 27/01/2012 12:23 pm
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For what it's worth in my limited experience top swing mech's tend to be rubbish, and I'd much prefer to fit a conventional if possible.

Back in the day XTR M952 Top Swing mechs were excellent (and expensive), whilst the conventional ones were cheaper and crap. Conventional now seems to be the default, but the 'linkage' design on the old XTRs was excellent.


 
Posted : 27/01/2012 12:25 pm
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thanks midlife for the picture really helps seeing it fitted, you also got the same year as mine 🙂
The one pictured looks like a xt model which is very similar to my xtr dull pull mech so hoping that will be fine as im going to change the crank to 2 ring from the normal 3 ring xt and ive been advised that a medium gage rear mech would work better with just the 2 rings!!!
Any views?


 
Posted : 27/01/2012 3:59 pm
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Also just like to thank everyone that has taken the time to post there help on here, ive just joined today and this is my first post on the forum.. newbie i think is the term!! so thanks for being gentle with me.. 😯


 
Posted : 27/01/2012 4:02 pm
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Technical reasons for using the different length cages mech:

Rear mech's are worked out by calculating the bikes capacity...
Capacity = (Biggest front ring - smallest front ring) + (biggest rear cog - smallest rear cog)

So assuming a 22 and 36 teeth front chainrings & a 11 - 32 cassette yours is:

(34-22) + (32-11) = 33T capacity.

Shimano XT rear mechs (for example):

SGS (long cage) 45T capacity.
GS (medium cage) 33T capacity.
Admitted these are old figures, check Shimano's web site for latest capacity, max cog sizes etc

So a medium cage mech would be fine but if you had a 11-34 tooth cassette (capacity would be 35), if you avoid big front/large rear combinations you'll get away with it..
That and being as it has a shorter cage it has less likely to catch stuff on the ground...


 
Posted : 27/01/2012 4:06 pm
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[i]So assuming a 22 and 36 teeth front chainring[/i]

and then went on to calculate using 22/34...opps

and way you do know you managed to post in the "chat forum" (off-topic), the bike forum is over <--- way, but as newbie we'll let you off this time 😀


 
Posted : 27/01/2012 4:25 pm
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Welcome Super4.

As for Super 4's front mechs : conventional, bottom pull works best. The original XT mech I had had the adjustment screws hidden behind the stays and were inaccesible. I got so fed up I got a new one : SLX m661. It's got the screws at an angle and is a whole lot easier.

As for the cage - assuming you're getting an SLX double & bash - a med cage (GS) works fine with a 32 tooth cassette - but not with a 34 tooth. I learnt that the hard way.


 
Posted : 27/01/2012 4:38 pm
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thanks for the tip z1ppy and for letting the forum howler slide this once..


 
Posted : 27/01/2012 5:21 pm