Originally Posted by
DannoXYZ
Are you sure it's the spider that's bent? Have you measure total +/- runout between the 5 arms? Most likely it's the chainring that needs bending and is also A LOT easier to bend back as well.
Using the FD cage as a guide, use a cresent-wrench on the chainring and bend it inwards or out as necessary.
Very old post I know.. knowledge is timeless.. i have a 1976 Bob Jackson with the same issue. I'm pretty sure the spider is off ( maybe from new..?) Though it's been in a wreck or two.. checking BOTH chainrings to see if they deflect in the same place should tell you if the spider is out of spec..I won't say bent.. Mine is. I did rotate the crank 180° and got the same result. I banged it with a rubber mallet but lacked the will to really smack it.. It's my winter roller bike so I won't pursue it.