B Tension Screw Has No Effect?

[sreten]

Hi,

AFAIUI the B screw only comes into play if you change the the rear gearing sizes to bigger.
AFAIUI on most new bikes adjusting the B screw will only makes things worse.
AFAIUI if you reduce the rear sizes, it typically won't help.

This assumes AFAIUI that the B screw is not needed for the default setup
of the derailleur and cassette on a new bike, like deraillleurs that have no
B screw, and you cannot fit larger rears, but you can fit smaller rears.
The B screw allows you to fit larger rears.

"it originally came with an 12-30 cassette, but now has an 11-28 on there. Is this why?"

Yes, in the way I understand whay it does. FWIW you could grind or fiie away the part
of the hanger that sets the position for more adjustment if thats what you really want.

rgds, sreten.

 

[gwhite]

It's not unusual for the B screw to fail to bear on the given platform on the frame as the configuration of the frame can cause this. In order to remedy this try reversing the B screw so that the head is bearing on the provided platform rather than the intended thread end. I usually replace the B screw with an Allen-headed one as the screws used are pretty flimsy.
In extremis, I've been known to build up the platform on the frame with an arc welder in order to provide purchase.

 

[bpsmith]

Cheers guys. I will investigate sometime soon. n+1 has drawn my attention for now.