Masonchat

Hi , I'm inclined to take on projects that can be a bit beyond my skillset, but I've learned a lot in doing so and normally get there in the end, but I've created the exact same problem in 2 different bikes , but I have no idea what is wrong and am all out of ideas.

The first bike was a simple enough chainring conversion , but ever since doing it, I could never get the shifting rear shifting to work as it should, currently it will not go into lowest gear , the derailleur is at full capacity , i can't understand what could have caused this, i rehoused and cabled it etc an no joy.

The second bike was a bigger conversion from a flat bar to r7000 105 to 2x10 tiagra.
I had the conversion working perfectly but the reach was to much and I couldn't get it right, so i gave up and switched back.
but when I reinstalled the rear 105 derailleur I've the same issue and cannot get it to shift to the lowest gear and again derailleur seems to be at its inward max but not lining up with lowest cog.

I did bring the first bike out to the new local tri hub shop but they fared no better than me and seemed very inexperienced to be honest.

the hangers aren't bent , and the derailleur is set up with the lower stud set against the hanger.

Ant ideas? I'm going out of my mind

FBinNY 

Questions.

Did you change to larger chainrings?
What else did you change?

Assuming no other issues, back off the inner (low gear) limit and try shifting by pushing the lower body in. If you can shift this way, adjust thd limit using the same method, then work on cable adjustments.

If you cannot shift that way, after backing off the limit, something else is going on.

IMO, this should be the first step in setting up an RD.

Iride01 

10 or 11 speed components for everything else? My son's bike was originally Tiagra 4700. But we changed it out to 11 speed 105 5800 RD and everything else 5800 except for the 2x Tiagra 4700 crank. It all works fine together. But I'm not going to vouch for a 11 speed RD with a 10 speed cassette.

You are talking about the low sprocket which is the one with the largest tooth count aren't we? I'd also wonder if the low limit is restricting the RD from moving. Or the cable is adjusted to short or you put it in the pinch bolt too short. When you try to shift into that largest rear sprocket (by tooth count) does it seem like you have to use a lot of force on the lever?

What about your chain. Did you change something else when this started and your chain is simply too short? Or does it not go into the lowest sprocket when in the small front either?

And what shifters are you using? If they are Tiagra, then which 10 speed series, 4500, 4600 or 4700?

If you didn't go by all the steps in the DM for setting it up, then that might be a good place to re-start back to square one.
https://si.shimano.com/en/pdfs/dm/RA...001-04-ENG.pdf

And for whatever shifters you have, you can plug in their number here and find the DM for them.
https://si.shimano.com/

alcjphil

When you talk about changes to two different bikes it might be better to start different threads to avoid confusion. I am not all that smart, therefore I I am confused

Masonchat

Thanks for that, basically one bike I only changed front chainring from 50/ 34 to 48/32 , shortened chain accordingly, but when I then had issues shifting to lowest gear largest rear cog , I eventually reversed it and changed chain. Still no joy and shifter at maximum inward trajectory, and no ,no strain shifting up .

And both bikes are flat bar, 105 r7000 2x11 components.

The other bike I changed while groupset from 105 flatbar to 2x10 tiagra , but changed evening back but yet again same problem with lowest gear , and yes in both largest and smallest chainrings

Kontact 

Generally speaking, if you put a Shimano 10 speed cassette on an 11 speed hub, you need to fit a 1.85mm spacer and a 1mm spacer that comes with the cassette on the freehub before the cassette goes on. Did you use spacers, and did you remove them when the 11 cassette went back on?

Masonchat

Yes to both, I'm feeling it has to be something with the reinstall of the 105 derailleur, but as far as i can maintain it is on correct position,

The 2x11 worked flawlessly prior to being taken off then reinstalled, and i had the 10 speed groupset working fine n has need baffled

Masonchat

The reason I mention the 2 is because somehow I seem to have created the same problem in both, so it's nearly to highlight that I'm most likely the cause .

I just don't know what it is I've done wrong

Kontact 

It is possible to get the current Shimano derailleurs out of place. With the chain on and in gear, loosen the mounting bolt half a turn to let it rotate forward and down. And then check that you have the B-link against the right stop post:

Duragrouch

In addition to comments above (all good), check the B-screw adjustment. Also, for shortening the chain, did you put on the large-cog/large-chainring combo, pull tight, then add 2 links? (I actually run a bit longer chain than this, but that is typical procedure.) I ask to make sure you didn't just shorten chain based on calculation, and here is why: Assuming 180 degree of chain wrap, reducing 10 teeth on a chainring means you actually only need to shorten the chain 5 links (which you can't do, you can only shorten by even numbers, so you shorten by 4 links). Now, contrary to this, rear derailleur capacities are rated based on full (360 degree) chainring and cog numbers, for ease of calculations by mechanics; tooth range of cogs + tooth range of chainrings = RD capacity needed. But in reality, the difference in chain length is only half of that. So (just arbitrary example) if your chainring got smaller by 10 teeth and you shortened the chain by 10 links, you shortened it too much, and it won't go on the large/large combo.

Masonchat

Thanks contact, this would be the current set up ??

Masonchat

that is the bike turned upside-down

Kontact 

Looks correct. So that's not the problem.

KCT1986

Have you done the test of loosening the low limit screw and then pushing the cage inwards (or pulling the cable if it's exposed along the downtube or chainstay)?

If it moves inward manually, then it may be a cabling/housing issue or shifter problem.

Was there any changes made to the cable or housing during the reinstall?

Masonchat

I had tried to shift them in manually and they wouldn't go far enough, but I had both chains off there when I read your post and tried again , and they would go well in, I don't know what I'd been doing wrong. But both sorted , so thanks for the tip , feel a bit daft now 🫣

choddo

So you just pushed them without chains and they went a bit further than they had with chains and then you put the chains back on and they still go further and are now fine?

Masonchat

They would go further without the chain, and it was much easier to see and align the jockey wheels without the chain , (which I had been doing with chains on)

The more recent bike issue the conversion bike , the fresh cable had slipped , I obviously only sinched it in place and never thought to recheck, didn't notice as only last few inches exit bike frame.

The other bike though is a mystery because I had that out to what should be bike mechanics and can't away with it the same and paid for the privilege, so don't understand what made the difference , but I'll take