Originally Posted by
daoswald
When I moved up from a 12-25 cassette to 11-28 I had to put the B-screw all the way in to keep the jockey wheel off the cassette, and that reduced shifting speed and accuracy. Removing one or two links from the chain improved the situation significantly, and I was able to back-out the B-screw a bit. So you may be on the right track.
You want to first assure that you CAN remove a link or two.
I'll check the math but just based on how much loose chain there is when it's on the big/big, my guess is I can. I'm pretty sure I did not install this chain, so it came too long from the shop (and the original cassette was even smaller).
Originally Posted by
Andrew R Stewart
Yes the upper pulley is so tight against the underside of the 32T cog that it is trapped by the chain from moving sideways. As mentioned the large cog capacity for this der is 27T IIRC.
A few solutions- You could mount the rear der on a Wolf Tooth or similar device that effectively lowers the der's mounting point. You could install a 9 speed MtB rear der that has a greater capacity. You could go back to the 27T max for the Tiagra der and instead mount a inner ring smaller then the 30T that is the OEM size. I run 26T grannies on a few of my otherwise lightweight bikes (for the Finger Lakes and my old body).
My vote is both the MtB rear der and the smaller granny ring. This way you get both the larger rear cog capacity as well as the greater chain wrapping capacity that a MtB der has. BTW I also run a smaller middle and large ring, then is the typical stock spec. on all my bikes. 26-36-46 is on a number of my bikes. Andy
Oddly, it shifts just fine even with the upper pulley where it is - it's noisy though because of the contact. It *is* a triple RD though, I don't think it's any shorter than my own wifli rear derailleur...
What physically changes about the RD to allow a 28 tooth or 32 tooth cassette in the back? (aside from chain take-up considerations)
Originally Posted by
trailangel
Chain too long.
Is that a 9sp chain?
9 spd yes, and probably. Came installed that long, I haven't touched it (yet). Strangely, it looks like I captured a quick disconnect link in that pic.
Originally Posted by
HillRider
+1 I have exactly the same thing on my most ridden bikes and I believe I'm at least your age or older. The Finger Lakes have some really big climbs. I've ridden Bon Ton Roulet for the past several years and i think i've seen most of the hard ones.
I spent four years in Ithaca and even rode my bike, but there are some streets I don't even want to walk up, much less ride up (Buffalo? Yuck!)