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29er Front Derailleur for max clearance

JackanoryJackanory Posts: 3
edited September 2012 in MTB workshop & tech
After many bikeless years, a move to the country prompted a purchase of a 29er to explore some of the woods and trails in my locale. I bought a Felt Nine Sport 2012 and am very happy with it but only noticed after the first ride just how tight the front derailleur clearance is - the Shimano Alivio FD-M430 top swing mech does a fine job but leaves much less than a centimetre's clearance between the screws at the top rear of its seat tube clamp and the rear tyre. When in the top rings front and back, the mech's cage is an even closer fit, barely 2mm from the tyre's sidewall and brushing the rubber 'hairs' on the tread.

From research, clearance seems a common problem for 29ers, and I'd like to maximise mine to avoid excessive mud-clogging of the mech (acknowledging it's always going to happen to an extent).

Can anyone recommend a suitable front mech that's more compact and would give better clearance between the side and front of the rear tyre? I think given the seat tube braze ons, top swing may be necessary but would take advice on that. Also, the crankset is an SR Suntour XCR 3 ring setup. Rear dérailleur is Deore M-592 Shadow 9 speed and the shifters are Acera SL-M390 if that's any significance (can you tell I'm a noob?).

Any thoughts welcome, cheers!

Posts

  • nicklousenicklouse Posts: 50,675 Lives Here
    you should not be really using the two big ring/cog at the same time.

    and you will need to provide images of what your issues are as it is unlikely much can be changed as most mechs have the same overall dimensions.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • The RookieThe Rookie Posts: 27,804
    If it's a high mount front mech, you'll gain clearnace by changing to a low mount (if it will fit) on 95% of bikes as the seat tube moves further away from the tyre further down.
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • cooldadcooldad Posts: 32,599
    If it's a high mount front mech, you'll gain clearnace by changing to a low mount (if it will fit) on 95% of bikes as the seat tube moves further away from the tyre further down.
    If he already has a top swing, that is a low mount.
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  • Many thanks for the replies.

    I've attached some photos to show the clearances, but I should clarify that I meant the proximity of the cage to tyre is at its most exaggerated when the chain is in the smallest crank cog and the largest cog on the rear cassette. As you can see, pretty damn close.

    I'm not sure whether a conventional (bottom) swing might be an option or not given the location of the tyre and fairly low-placed braze-ons. Looking at pictures, their mech clamps seem to project out less behind the seat tube, though their higher placement could mean they end up impinging more on the tyre clearance anyway.

    I had a look at the Shimano XT M-770 top swing mech, which seems to be a little more compact, but it's impossible to really tell unless you've seen the thing in person. Maybe it's just a fact that truly 29er-friendly mechs are yet to be developed!
  • supersonicsupersonic Posts: 82,708 Lives Here
    poor frame design I am afraid! Could try a longer front chainline.
  • The RookieThe Rookie Posts: 27,804
    The cage position is unafected by which rear sprocket you use, but you could try tweaking the low stop to eak out a few extra mm.
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
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