jskash

I ride a Giant Escape. The bike is a 3 by 9 set up. Since changing the cassette I have not been able to shift into the hardest gear. I know one of the screws in the picture needs to be adjusted but I don't know which screw to use. Please pardon my lack of mechanical understanding. I would like to see if I could do this myself instead of taking the bike back to the LBS. They have been swamped.

Bill Kapaun

The H screw. High limit.
Go in small increments. Too much and the chain goes off the cog.
Have you tried turning the barrel adj. IN a couple clicks? You might be jumping the gun with turning screws.
IF you turn screws, keep track of how much so you can return to where you started in case you go the wrong way.

asmack

Don't use the H screw to adjust this. Move your barrel adjuster to allow maximum slack in the cable. Undo the clamp bolt to let all tension off the cable and use the H screw to line the chain up with the small cog. Tighten and secure the cable, making sure it's not so tight that it moves the chain. Use the barrel adjuster to make small adjustments to fine tune the shifting. Similarly, with full tension-- just pull on the wire, use the L screw to make sure the chain won't go past the large cog.

dsbrantjr

You will help avoid stripping the screw's head or the threads in the derailleur if you push the derailleur by hand and follow with the screw rather than trying to drive the derailleur against the spring with the screw. JIS screwdrivers fit the cross recess better than Phillips.

andrewclaus

I'd reiterate what's said in post #3 above. It's usually best to just start from scratch. Those five extra minutes could save you thirty.

scott967

I think this is under-appreciated. It is sooo easy to round out the screw head. But I have never seen JIS screwdrivers for this (but I suppose do some searching online and they will pop up). Now my SRAM has hex-head screws which eliminates that issue.

For OP: run the rear shifter up and down and watch which screw is close or making contact in the biggest and smallest gear. The purpose of the screws is to prevent the derailleur from moving to far in (on the biggest gear) or out (on the smallest gear). But the tension in the cable (gross adjustment with the cable set screw, fine adjustment with the barrel adjuster) determines how well the shifts work. If the gross adjustment is off, you have trouble getting it to shift to the biggest or smallest gear. The fine adjustment you can check in the middle gears, seeing how reliably it shifts up (bigger gear) or down (smaller gear). If it won't go to the bigger gear you need more tension in the cable and vice-versa.

scott s.
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jskash

I took my bike to the LBS yesterday to have them look at the shifting. Two people tried for at least 20 minutes to get the gears into the smallest cog but were unable to. They settled on ordering me a new derailleur. Hopefully that will solve the issue. It is not much of a problem for me as I very rarely use the smallest cog.

woodcraft

Did they check the hanger alignment?

Who changed the cassette? If the symptom started then, was it checked for position?

Unlikely that a new RD is needed, & sounds like incompetence at work.

jskash

I guess we will find out after they put the new derailleur on. I do want to cut the mechanic a bit of slack. The original work was done one of the first days of the pandemic and the store was closing early, so everyone was a bit tense.

woodcraft

So the shop changed the cassette and maybe the shifter, and after that it didn't shift right so now they are going to replace the RD?

Doesn't sound great, but hope it works out.

Retro Grouch 

Without seeing the bike I tend to agree with woodcraft.

Was it ever right? Derailleur limit screws, once correctly set, very seldom need readjustment.

You can check your derailleur hanger alignment yourself.
1. Prop your bike up vertically against a wall or something.
2. Shift into a gear combination that makes the derailleur cage point downward.
3. Now examine your derailleur from the back of the bike. Does your derailleur cage seem to be pointing at the rear wheel? If it does, there's your problem. It should be pointing straight down in the same plane with the rear wheel.

Miele Man

Would you post an image of your rear derailleur and cogset, taken from the rear of the bike, with the rear derailleur pointing down so that we can see the angle if any of the derailleur cage? That way we'd have a much better chance of knowing if your derailleur hanger is bent.

An image something like this but closer showing the rear derailleur and frame.



Cheers

woodcraft

Like that?

Miele Man

That was an extremely helpful post - NOT. LOL

Cheers

woodcraft

Sorry man, lost my focus...

jskash

The saga of my shifting problem was finally solved today. A new derailleur was ordered and put on the bike. That still did not solve the problem. After quite some time I went up to the front of the store where the mechanic was working on the bike and suggested that possibly the new cassette that had been put on two months ago was the culprit from the beginning since even changing the derailleur didn't work. It appears he was thinking the same thing I was because shortly after that he got a new cassette to put on the bike. It worked. In the meantime, The shifter and derailleur had been replaced. Fortunately I only ended up paying for the derailleur which is what the invoice stated.