I was hoping someone could provide some suggestions on this...

I am experiencing some strange problems with my rear derailleur reaching the largest sprocket on my cassette. I'm running a Shimano 105 9-speed derailleur and an 12-23 cassette. I was out riding yesterday and had a slight crash and noticed that I was unable to get into my largest cog. After inspecting my bike, I can see visible scrape marks on the derailleur but it doesn't look like there is too much damage. The problem I experienced afterwards was that when I tried to shift to the largest cog (when I hit the first hill), I was unable to do so. Honestly, I'm not sure if this is because of the crash or something else because it was my first attempt to get into that cog. I do know that I was riding in it last week as I did the same route and same hill and always have to go to my lowest gear.

I went home and inspected the derailleur further found that there was no damage to the derailleur hanger. Also, I opened up the limit screws to the point of them almost falling off and still could not get into the largest cog. Finally, I removed the derailleur cable and tried to push the derailleur into the gear and still could not do so. I tried all this being in the front chainring and the length of the chain is correct, so I'm totally stumped.

I bought a new rear derailleur today and will try that tonight, but I was hoping someone would have some ideas of what to look into or what to try. I think I've tried everything, but I'm a newbie mechanic, so any advice would be appreciated.

Thanks in advance.
Dipper

Your RD hanger is bent. Either buy an alignment tool or take it to a shop that has one.

https://www.parktool.com/products/det...8&item=DAG%2D2

That's what I think too. If you have a 9 or 10 cog cassette it doesn't have to be very far out of alignment to cause the problem that you describe.

...Or if you have one of those replaceable hangers, just order a new one.

The derailleur-hangers are designed to bend. Better that than your frame bending (which is why they bend first). So I concur with the above. Having a shop with one of these $60 tools (Park Tool DAG-2) won't charge you more than $15 to check/fix same. It's easy. And getting one of the replacement-types won't kill you either.

Anytime you have a small crash on the drive-side, this is what to look for.

Order a new what. Frame? A+ effort though

Let's not run over the bike with the Bulldozer just yet, ops, it has more moments on it still. Have you finished the order for the Stop-Sticks that fit in a front-basket yet?

Just get it checked for the derailleur-hanger being misaligned. If it so much as falls over on the drive-side, and the shifting is off - get it checked/fixed. Happens all the time. Such is why I broke down and got me a DAG-2. Go get one. Kick over all your friend's bikes. Make a few $100. Move away!

A new "replaceable hanger". It says so right there in the sentence you quoted. A+ effort on reading comprehension though.

Do you think I should stop running Ouzo to Toronto, Dude?

Yeah, I can't read tonight :/

Hi All,

It seems that the problem was with the derailleur itself. It seems that the crash may have slightly bent the cable bolt/body of the derailleur such that the underside of the bolt hits the inner side body of the derailleur before it can get to the low gear. There is a slight bend in the derailleur hanger, which I will replace tomorrow as it is replaceable, but when I installed the new derailleur I'm able to get beyond the low sprocket if I set the L - adjustment far enough.

Thanks for all the help.
-Dipper

Seems I have a new friend : )
Plenty more where that came from ; )