trenzterra

Hi all,

I have a 20" folding bike (400mm chainstay) that I bought new recently. Decided to change out the default Tiagra groupset with Shimano 105 R7000 mid-cage, SL-RS700 shifters and 105 11-32T cassette. Chain is an 11 speed Ultegra chain and I have checked that it runs in the correct direction (was also using an KMC X11EL initially with the same issue)

I am experiencing the following indexing issue:

• When I index the second smallest cog (let's call this 10th gear), everything works fine until I hit the 5th or 6th gear where the chain starts to rattle against the next sprocket. A small turn of the barrel adjuster clockwise solves this. However, when I move up to the 3rd and 2nd gear, the rattle comes back again, and I have to turn the barrel adjuster clockwise a little bit more. However, doing so, when I go back down to the 9th or 10th gear, the indexing becomes off and I need to turn the barrel adjuster back counter-clockwise. Essentially, I cannot get both ends of the cassette to work in harmony.

So I went out to buy the Park Tools DAG 3.0 in hopes of fixing this issue. True enough, it was a little off, so I tuned the 12 & 6 and 3 & 9 positions very carefully. While this made the shifts a little better, I could never get perfect indexing but a wee bit slightly off in the larger and smaller sprockets. I have checked and re-checked hanger alignment a few times, including replacing the hangers. I have made sure the margin of error is within 1-2mm (it's hard to get any better than this because the DAG itself has a very slight bit of play).

Shifting wise, everything is smooth, however. I have also tried the following:

• Changed shift cables and shift housing twice (tried both lubing shift cable and not lubing). Housings are Jagwire Pro and I checked to make sure there is a sufficient loop
• Tried my old Tiagra RD (which has the same ratio as the R7000) - same issue
• Tried a new Ultegra 11-30T cassette as well
• Adjusting B tension back and forth

Anything else that I could check? Could it be that the RD is exerting too much pressure on the hanger such that it bends a little bit more inwards in the smaller cogs, which is something the DAG will be unable to replicate?

Iride01 

Why would we call the smallest cog the 10th gear? Is the largest cog the 0th gear on your bike? SL-RS700 shifters are 11 speed. The Tiagra you replaced was 10 speed. So if the cassette you put on is an older version 105 of the 10 speed era, then there is a problem.

I guess what I'm trying to ask is that this is a 11 speed cassette. Right?

trenzterra

Yes it's an 11 speed cassette with the 11 speed 105 and shifter. I was referring to the second smallest cog as the 10th gear. I have no issues with indexing on the smallest (11th) and largest (1st) sprocket as they are set in place by the limit screws and the largest sprocket has no other inward cog to rub against.

Iride01 

Okay, I can go with that. I guess I shouldn't skip every other word when I read.

When you say you turn the barrel adjuster to get rid of the clatter, that is the barrel adjuster on the rear DR isn't it? Just checking to be certain.

If everything is from the road bike Shimano group then I don't see much to tell you. 11 speed cassette replacing a 10 speed cassette, there is a spacer involved and I don't remember which gets the additional spacer. You'd think it'd be the 10 speed, but I seem to remember it's actually the 11 speed that gets the extra spacer.

Chain stay length might be coming into play here too. Some of the issues that 10 and 11 speed rears have had to overcome is the angle of the chain when in the big/big and small/small. Shorter chain stays expose that issue more. Though I don't know that 400 mm is that short although my Tarmac's chain stay is 410 mm.

How close to the cog is the jockey wheel? Is it further or closer in some gears than the other?

All of this just wild conjecture on my part.

trenzterra

Thank you. Yes, the barrel adjuster on the RD. It's the 10 speed that needs a spacer.

I took some photos of the DR using my camera and the DR cage seems perfectly aligned with the cassette. Also rechecked DR hanger alignment.

I moved B tension all the way until it rubbed on the largest sprocket and then I backed it off a little. Not sure how many millimetres that is but it's about 1.5x of the height of a chainlink.

What I did notice was that my chainline was straight on the 7th gear (instead of the 6th or the middle of the cassette). So I tried moving the chainring inside of the crank spider, but this moved the chainline too inwards, so I added a spacer on the BB to compensate. Now the chainline seems to be sitting somewhere along the 6th gear (maybe biased a little towards the 7th) but it seemed to help with the noise a little. Guess I'll keep monitoring and see if it's just placebo.

Iride01 

That just sounds odd. Makes me think the OLD of the hub is wrong or that the mfr did some things to accommodate the folding of the bike. Do they even offer an 11 speed version of the same model? If not, then maybe that's because they found that 11 speed didn't work with the changes they had to make for it to fold.

This is the original crank isn't it?

Rick53

It's counterclockwise

trenzterra

What's counterclockwise?

trenzterra

Well the original chainring had a slight inward offset to accommodate a chain guard on the outside.
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I switched it out to an oval narrow wide ring which didn't have that offset, though when I stayed on 10 speed I didn't notice any issues with indexing or the chainline being a little out on the narrowwide except the chain would sometimes drop to a smaller sprocket when backpedalling on the highest gear.

Anyway after moving the chainline a little bit inwards, shifting does seem to be slightly better. I used to get a rumble when in the smaller cogs when pedalling on the stand, but the noise seems to have reduced (which is weird, because my smaller cogs are being more crosschained now, but it could also be that the larger cogs are less crosschained and my barrel adjuster position is shifted). Still, the range of perfect shift positions on the bike stand is very narrow (about two clicks on the barrel adjuster in either direction and indexing starts to be off on certain gears). Though strangely enough, when actual riding (as opposed to the bike being on a stand) it isn't as noisy and I can move the barrel adjuster one whole turn and not notice any difference I noise, even in a quiet park.

I'm just trying to wrap my head as to how chainline affects shifting, and why my indexing is being particularly picky, as it is rather peculiar given that my hanger is aligned and I have checked that my DR cage is aligned as well.
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Iride01 

There isn't much to have to wrap your head around. You want the center of your front stack of rings to hit as close to the center of the rear stack as is possible for optimal shifting across the range of the cassette.

If you mix and match components from different genres of cycling or different rear drop spacing then you might find some funny inconsistencies. And since your bike is a folding bike, there may be things they did to make it fold decently and sacrificed ideal chain line. Like I said before, maybe they found a 10 speed works well enough but an 11 speed doesn't.

Certainly you might be able to change it up some.

Rick53

What I found online says when you are climbing the cogs from smallest to largest the rattle is fixed by a slight adjustment Counter clockwise . When you are coming back down if it does not shift down right away a slight clockwise adjustment is needed .

Did you by chance adjust the H or L screws or touch the B Screw

trenzterra

Thank you. Yes, my issue is that when I do a slight adjustment in one direction for certain cogs, the other cogs become out of tune and vice versa. My 'ideal' adjustment right now has no rub on all gears except the 3rd smallest cog, where there is a slight 'tick'.

Now that I think about it, I don't think adjusting the chainline seemed to help. The chain goes on and off the chainring without any issue. My problem is that there is a very slight misalignment only in certain gears resulting in the chain leaving the upper jockey only to contact the edge of the teeth and I hear a very slight ticking noise resulting from the chain hitting the teeth and trying to align itself to the cog.

I've changed the cables and housings at least 3x, experimenting with different cable housing lengths and angles... swapped cassettes... even went out to get another set of RD and shifter.. but nothing seems to help.

trenzterra

Went to two reputable LBSes and both said my bike was fine. I guess I'm just being too picky.

trenzterra

Just an update on my issue and perhaps some closure.

I re-aligned the hanger again and also the B-link this time. Same issue. Observed from the back of the bike that with each incremental shift from smaller -> bigger cogs, the gap between the next biggest sprocket and the chain closes up ever so slightly, and the 'error' compounds such that it starts rubbing on the next biggest sprocket when hitting the third/ fourth sprocket (though to be honest this seems to be just a 0.5mm margin of error). This is puzzling because I have aligned the hanger and B-link to utmost accuracy.

Anyhow, I tried pulling the hanger outwards more. Basically I purposefully made it misaligned outwards by about 3mm and tried again. This time, the chain sits perfectly in the middle of each sprocket and there is no rub whatsoever. However you can tell the derailleur cage is now a little tilted outwards and no longer absolutely parallel with the cassette. Strange, isn't it..

The only reason i can think of is that perhaps the derailleur hanger gets bent inwards somewhat due to the force that is exerted by the chain hanging on the RD...? And so I have to bend the DR hanger outwards to compensate for this.

oldbobcat

Some hangers are "soft," so its possible that tension from the chain or the cable was tweaking the hanger. Also, occasionally, I've seen bent Shimano derailleur cages from right out of the box. It is possible that you compensated your hanger for a bent cage. But hey, if it works, ride it.