Front Mech <> Braze-On?

newburb_1968
newburb_1968 Posts: 114
edited January 2009 in Workshop
Hi all
Just a bit of a numpty question.

I have had a bit of bad luck recently and hopefully I have seen the back of it.
(The old saying is bad luck comes in three)

1> Snapped seat post.
2> Snapped rear gear cable in STI.
3> Front 105 Mech bent and twisted.........This is down to my own silly fault, I replaced the chain on Saturday and as I snapped the pin off I must have gone a bit too far through. So when I set off to work this morning I had gone as little as a mile before something was jamming the peddles. So after a few pushes I stopped, to my horror the pin a part jumped out and got caught in the front mech causing it to bend under the chain ring. Which I had to head back home.....which is a right pain because I drive 35miles part way into London.

Anyway my numpty questions.

What is a Braze-on?
How would I identify weather I have a braze on or not?

I have a trek 2008 1.7 105 triple at the moment (5603 front mech) is this a braze on or not.

I would be so grateful for someone to educate me out there, so I can order a part and get back out on the road.
Regards
Barry

Comments

  • a frame that requires a braze on has a hanger on the frame near the bottom of the seat tube if your frame doesnt have a hanger here, then you need a clamp on front mech.
  • Confirm what said by Rapid uphill. Your trek is aluminium and is unlikey to have a braze on, normally you find them on steel frames

    This is how a braze-on hanger looks like

    http://i173.photobucket.com/albums/w55/ ... G_7940.jpg
    left the forum March 2023
  • Thanks very much, all is clear.

    I do not have a braze on.

    Thanks again.
    Regards
    Barry
  • andy_wrx
    andy_wrx Posts: 3,396
    Confirm what said by Rapid uphill. Your trek is aluminium and is unlikey to have a braze on, normally you find them on steel frames

    This is how a braze-on hanger looks like

    http://i173.photobucket.com/albums/w55/ ... G_7940.jpg

    I'm being really picky, and I can see you've very successfully answered Newburb's question, but just in case (I suppose it might happen ! :shock: ) someone in future uses the search function because they have the same question...

    Yes you'll find a 'braze-on' on a steel frame, but you'll also find them on many carbon or aluminium bikes, where rather than being brazed on, they're riveted or glued on.

    The band-on style has a hinged circular clamp biult onto the front mech and fits to a circular downtube, in two sizes of 25.4/1-inch typically on steel frames and 31.8/1.25-inch typically on alu frames.

    If the tube is not circular e.g. fancy oval or aero teardrop shape or tapering, or is too big for a 1 1/4" collar, then there will be the fixing plate attched to the downtube - brazed, glued, riveted, screwed - as in the photo and the front mech bolts onto it, sliding up & down the slot as required.