Tandem Cycling - Front derailleur

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Faddy

09-11-06, 11:10 AM

Hi, we took our new (used) Cannondale MT800 for its first meaningful ride this weekend and really enjoyed it.

I noticed that when we are in high gear (big ring in front) there was a click-click sound when pedalling. Upon closer inspection we saw that my wife's crank (stem that pedal is on) chafes against the front derailleur (sp?) when it passes, meaning that the derailleur shifts too far over when in high gear.

I tried to shift it back one click but it then moves to the middle ring. It appears that it might be a little bent. Any advice on adjusting/bending the derailleur so that there is no friction when pedalling? Or is it better to have LBS look at it?

Apologies for any incorrect bike terminology or lingo as I am still new to this, but learning fast.

Thanks.

TandemGeek

09-11-06, 01:17 PM

If you're not familiar with bicycle mechanics, let your LBS make the adjustments... which, depending on why it is rubbing, could include:

1. Making sure the stoker's bottom bracket is properly centered and, if a square taper BB and cranks are used, that the cranks haven't been over tightened.

2. If the derailleur is properly aligned with the chain rings, merely adjusting the derailleur's upper limit (aka, "H") screw to keep the cage from travelling far enough to contact the cranks, while still allowing it to properly shift the chain and not drag in the big chain ring / small cog combination.

3. If the derailleur is improperly aligned with the chain rings, loosening and derailleur clamp and adjusting the derailleur so that the lower edge of the cage is parallel with and vertically aligned 1-2mm above the large chain ring's teeth

4. If the cage is bent, bending it back into proper shape and then doing a combination of 2 & 3, above.

Note: You may want to review the information on front derailleur adjustments at Park Tool's "How-to" Website: http://www.parktool.com/repair/readhowto.asp?id=75

zonatandem

09-11-06, 03:44 PM

*IF* it is a bent derailleur, bit of judicious bending it back, with needle nose pliers, could help.

Faddy

09-11-06, 04:52 PM

Thanks for the feedback! I will take another look and see if I can figure it out.