What front derailleur do I need

gyblue
gyblue Posts: 7
edited April 2019 in Workshop
Hello all
I am looking for the right front derailleur for my trek 1000.

I have an 8-speed cassette and Shimano Ultregra derailleur on the rear and a Truvativ double crankset.

Can someone please tell me what clamp front derailleur I need to get?

Thanks

Andrew

Comments

  • me-109
    me-109 Posts: 1,915
    Braze-on? Clamp on?
  • gyblue
    gyblue Posts: 7
    Clamp on please
  • arlowood
    arlowood Posts: 2,561
    Almost all front derailleurs are sold to accommodate a braze-on mount. ie where a bracket already exists on the seat tube for attachment. However if you buy a new boxed derailleur it will usually have a clamp included with shims to accommodate different seat tube diameters - I would suggest the new 105 7000 model as it has a built in cable tension device that makes the set up much easier.

    https://www.wiggle.co.uk/shimano-105-r7 ... WEEALw_wcB

    A fitting and set-up guide is provided here

    https://www.youtube.com/watch?v=9zZWAUp6oOE

    If you buy second hand then you may need to source a separate clamp. In that case you will need to measure the diameter of your seat tube and buy a suitable clamp-on adapter such as this from Planet X

    https://www.planetx.co.uk/i/q/FMPXCLAMP ... n-sram-yaw)

    It comes in 2 sizes (28.6mm and 34.9mm) depending on the diameter of your seat tube
  • gyblue
    gyblue Posts: 7
    Thanks Arlowood
  • i.bhamra
    i.bhamra Posts: 304
    arlowood wrote:
    Almost all front derailleurs are sold to accommodate a braze-on mount. ie where a bracket already exists on the seat tube for attachment. However if you buy a new boxed derailleur it will usually have a clamp included with shims to accommodate different seat tube diameters - I would suggest the new 105 7000 model as it has a built in cable tension device that makes the set up much easier.

    https://www.wiggle.co.uk/shimano-105-r7 ... n=Shopping

    Is this the case? Haven't bought a new front mech for a while but in the past when buying braze-on mechs there would be no clamp included, you'd have to buy one separately and in that case you'd need to make sure it was the right size for the OD of your seat tube.

    If you bought a band on shimano mech then the clamp was generally non-removable so you'd need to make sure you got one with the clamp which was the right size for seat tube or source appropriate shims (no good if the clamp is for a narrower tube though)
  • keef66
    keef66 Posts: 13,123
    Ditto. If you're shopping for a Shimano FD you generally have to choose braze on or one of 2 clamp sizes, usually all subtly different prices.

    Buying a replacement for my winter bike I bought a band-on to suit the seat tube, but when I went to take the old one off I found they'd built it with a braze-on mech + separate clamp so I could've bought the slightly cheaper braze-on mech...

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