Problems shifting rear derailleur some gears

[zaxatron]

Hi everyone,

Happy New Year.

I have rebuilt my old Merida S3 bike by installing a Sunrace 11-40 cassette in the rear using a roadlink to adapt this cassette to a road bike.
The rear derailleur is a Tiagra 4600 middle cage.

I have checked hanger alignment with the BikeHand hanger alignment tool and it is fine.

So I adjust cable tension using the rear derailleur barrel adjuster (front derailleur [50/34] positioned in the big chainring and rear derailleur in the highest gear). I get a smooth shift going from 10-9-8-7-6-5, then there is hesitation from 5 to 4, so I increase the tension which fixes this problem.

But on the way down when I go from gear 4 to gear 5 I see that the chain in the back is trying to get off 4 but it struggles a bit. So I decrease the tension and it works. But this new adjustment recreates the first problem going from gear 5 to gear 4, I cant get rid of it.
Sometimes it works ok.

The chain is in good condition since I used a chain check tool to make sure it is not slack.
The stainless steel cables are new.

By the way the B screw is pushed in most of the way otherwise I get too much slack in the chain when it is in the 40 cog sprocket.

I cannot work out why I can't fix this problem.

I understand that this is a non standard setup, but there are a lot of youtube videos that show you how to fit a mountain bike rear cassette to a road bike. I did this to make my steep climbs a bit easier.

Any ideas?

Thanks

Regards

Zaxatron

[Baalzamon]

Have you replaced the cable outers?

[sammutd88]

Make sure you've set the high and low limit screws correctly, without the cable under tension. Sounds to me like the high limit screw isn't quite set correctly.

[zaxatron]

Have you replaced the cable outers?

Thanks for your reply.

The cable outers have been there for about 4 months, probably not the best brand.

I used Mars cable outers, not Shimano or Jagwire.

When I cut them I opened up the inner hole and filed it flat removing all burrs.

I will get new outers and see if this files the problem.

[zaxatron]

Make sure you've set the high and low limit screws correctly, without the cable under tension. Sounds to me like the high limit screw isn't quite set correctly.

Thanks sammut88.

I set the high limit screw on the rear derailleur so that the chain does not go past gear 10 (high gear 11 tooth cog)

What else should I do?

Please explain procedure for setting these without cable tension.

Thanks

[sammutd88]

Shift to the smallest cog and loosen cable anchor bolt to release all cable tension. Look behind and use the "H" screw to set the derailleur so that the pulleys are directly under to "just outboard" of the smallest cog. Now push the chain up to the largest cog while rotating the cranks and set the "L" screw to be directly under the largest cog. Once you've done that, you can reattach the cable and make slight adjustments to the shifting via the barrel adjuster. It's important that the limit screws are set to ensure the derailleur can get to every cog and also doesn't overshift into the spokes past the largest cog. It's not dificult, but if you are having issues, your local bike shop can sort it out in 10 minutes.

I would also recommend you check out GCN channel on Youtube. They have lots of mechanical tutorial videos with little tips and hacks to make your life a lot easier.

[A_P]

Not likely to be limit screw related in the middle of the casette
Check the float on the top jockey wheel
B-tension moves the top jockey wheel down and away from the casette which can give vague shifting performance.

[10speedsemiracer]

I think you're going to have issues getting this to work long-term. Wolftooth indicate that your rear derailleur cog limits still need to be observed, and while there is some tolerance with Shimano figures, I think expecting your Tiagra GS to cope with 40t is asking a bit much. Is listed as 30t max, but should be able to do 32t and maybe even 34t if you're careful to not cross-chain.
Are you using the original length chain, or have you replaced it with a longer unit?
If you really want to make this work, I think you'll need to swap derailleur for a long cage unit that can get up to 38-40t. In the meantime, to sort out your shifting issue:

*check and clean the bottom bracket cable guide
*replace all cable housing on the gearing with better quality stuff
*retune your RD as sammutd88 has said. (the main thing is that the top pulley is under the respective cassette cog)
*get the B screw adjustment right (not just the H or L)
*pull shifter cable thru until tight but not moving the derailleur sort of tight, clamp it (make sure that RHS shifter is fully released and chain is on smallest rear cog).

I'd be interested to see how the chain runs on 34 / 40t, and 50 / 11t. Maybe post some pics.

[Thoglette]

Outside the box: how old is your chain? 1% is the limit before it will start really messing with things (that's 1/8th over 12 links). One should change at 0.5% (1/16th over 12 links or .2mm over 10)

[ironhanglider]

I think you're going to have issues getting this to work long-term. Wolftooth indicate that your rear derailleur cog limits still need to be observed, and while there is some tolerance with Shimano figures, I think expecting your Tiagra GS to cope with 40t is asking a bit much. Is listed as 30t max, but should be able to do 32t and maybe even 34t if you're careful to not cross-chain.

The purpose of the road link is to lower the derailleur so that it can have clearance for a 40T cog. What Wolftooth indicate is that the capacity limits need to be observed which for a 4600GS is 39T. In this case the required capacity is about 45T. I have run an Ultegra derailleur out of spec before on a tandem (55-42-30 x 11-34). If you set it up so that it can physically cope with the big-big combination the bottom chain run will foul when on the small-small combination which is noisy rather than dangerous and enough to prompt you to choose a better combination.

Are you using the original length chain, or have you replaced it with a longer unit?

I'd hope it was a new chain but it doesn't sound like it in the original description. As above if the chain cannot cope with the big-big combination and you try to shift into it anyway by mistake, it is a really bad outcome particularly under load.

If you really want to make this work, I think you'll need to swap derailleur for a long cage unit that can get up to 38-40t. In the meantime, to sort out your shifting issue:

*check and clean the bottom bracket cable guide
*replace all cable housing on the gearing with better quality stuff
*retune your RD as sammutd88 has said. (the main thing is that the top pulley is under the respective cassette cog)
*get the B screw adjustment right (not just the H or L)
*pull shifter cable thru until tight but not moving the derailleur sort of tight, clamp it (make sure that RHS shifter is fully released and chain is on smallest rear cog).

I'm sure duck! is sick of typing this - I've read it from him often enough, but the length of the cage has nothing to do with whether the derailleur can put the chain on the biggest cog. The cage is only there to absorb the extra length. It is the derailleur body that dictates the size of the largest cog. See the Shimano specs Both short and medium cage versions can cope with a 30T cog, but there is a 5T difference in capacity.

I'd be interested to see how the chain runs on 34 / 40t, and 50 / 11t. Maybe post some pics.

I'd also be interested in the 34/11 and the 50/40 if it can.

Cheers,

Cameron

[10speedsemiracer]

I think you're going to have issues getting this to work long-term. Wolftooth indicate that your rear derailleur cog limits still need to be observed, and while there is some tolerance with Shimano figures, I think expecting your Tiagra GS to cope with 40t is asking a bit much. Is listed as 30t max, but should be able to do 32t and maybe even 34t if you're careful to not cross-chain.

The purpose of the road link is to lower the derailleur so that it can have clearance for a 40T cog. What Wolftooth indicate is that the capacity limits need to be observed which for a 4600GS is 39T. In this case the required capacity is about 45T. I have run an Ultegra derailleur out of spec before on a tandem (55-42-30 x 11-34). If you set it up so that it can physically cope with the big-big combination the bottom chain run will foul when on the small-small combination which is noisy rather than dangerous and enough to prompt you to choose a better combination.

Are you using the original length chain, or have you replaced it with a longer unit?

I'd hope it was a new chain but it doesn't sound like it in the original description. As above if the chain cannot cope with the big-big combination and you try to shift into it anyway by mistake, it is a really bad outcome particularly under load.

If you really want to make this work, I think you'll need to swap derailleur for a long cage unit that can get up to 38-40t. In the meantime, to sort out your shifting issue:

*check and clean the bottom bracket cable guide
*replace all cable housing on the gearing with better quality stuff
*retune your RD as sammutd88 has said. (the main thing is that the top pulley is under the respective cassette cog)
*get the B screw adjustment right (not just the H or L)
*pull shifter cable thru until tight but not moving the derailleur sort of tight, clamp it (make sure that RHS shifter is fully released and chain is on smallest rear cog).

I'm sure duck! is sick of typing this - I've read it from him often enough, but the length of the cage has nothing to do with whether the derailleur can put the chain on the biggest cog. The cage is only there to absorb the extra length. It is the derailleur body that dictates the size of the largest cog. See the Shimano specs Both short and medium cage versions can cope with a 30T cog, but there is a 5T difference in capacity.

I'd be interested to see how the chain runs on 34 / 40t, and 50 / 11t. Maybe post some pics.

I'd also be interested in the 34/11 and the 50/40 if it can.

Cheers,

Cameron

Understand your comments and I probably should have been clearer, but got lazy typing the essay. I think OP may get away with this using something like the SLX long cage, giving derailleur body length and enough cage to handle metres and metres of chain.

Personally I think OP should abandon the 40t Alpine mountain goat gear, and perhaps try an 11-34 with a 30t front. Probably more workable.

[zaxatron]

I think you're going to have issues getting this to work long-term. Wolftooth indicate that your rear derailleur cog limits still need to be observed, and while there is some tolerance with Shimano figures, I think expecting your Tiagra GS to cope with 40t is asking a bit much. Is listed as 30t max, but should be able to do 32t and maybe even 34t if you're careful to not cross-chain.
Are you using the original length chain, or have you replaced it with a longer unit?
If you really want to make this work, I think you'll need to swap derailleur for a long cage unit that can get up to 38-40t. In the meantime, to sort out your shifting issue:

*check and clean the bottom bracket cable guide
*replace all cable housing on the gearing with better quality stuff
*retune your RD as sammutd88 has said. (the main thing is that the top pulley is under the respective cassette cog)
*get the B screw adjustment right (not just the H or L)
*pull shifter cable thru until tight but not moving the derailleur sort of tight, clamp it (make sure that RHS shifter is fully released and chain is on smallest rear cog).

I'd be interested to see how the chain runs on 34 / 40t, and 50 / 11t. Maybe post some pics.

Hi 10speedsemiracer,
thanks for your usefull reply.

I have already done the following:
check and clean the bottom bracket cable guide
get the B screw adjustment right
pull shifter cable thru until tight but not moving the derailleur sort of tight, clamp it

I sized a new 10 speed shimano chain using the Parktool Company method (big sprocket in the rear and big chainring in the front bypass rear derailleur)

The Shimano RD-4600-GS RD is classified has having 39T Total Capacity

When I calculate the RD capacity that I should have, I get the following result:

[ Largest Front Ring - Smallest Front Ring ] + [ Largest Rear Ring - Smallest Rear Ring ] = Required Capacity

[ 50 - 34 ] + [ 40 - 11 ] = 45T

The Shimano RD4600-GS ha a capacity of 39T.

I watched several youtube videos in the past that suggest that a combination of a middle cage RD + roadlink should work even though it pushing outside its range.

The Low and High limits/B screws are set correctly. I had a bike mechanic check them for me when I first finished the built a few months ago.

It was running fine except the mid gear issue.

On the Wolftooth site the specify this:

Compatibility:

10s Cassette Compatibility:
11-32: Not Required (GS medium cage rear derailleur works)
11-34: Single or double chainring
11-36: Single or double chainring (be sure to not exceed the derailleurs capacity)
11-40: Single or double chainring (be sure to not exceed the derailleurs capacity)
11-42: Not supported

Now I am not sure if there is a long cage RD for the Tiagra 4600 series groupset

What do you recommend I should replace it with?

Regards

Zaxa

[zaxatron]

.....I just want to add that I do not have problems when I am running the chain from big/small chainring to biggest sprocket in the rear.

The main problem is going from gear 7 to gear 6 and vice versa. Every other gear combination works fine.

[10speedsemiracer]

I think you may need to delve into the MTB derailleurs, and I'm not going to pretend to know what I'm talking about as far as MTB derailleurs are concerned. In another thread on this forum somewhere I remember someone talking about 10sp shifters, 10sp MTB cassette and a 9sp MTB rear derailleur (I think), something about a 9sp MTB derailleur having the same pull as a 10sp road. Maybe it's as simple as finding a 9sp MTB SGS derailleur and running that.... How was it with the resized chain btw?

[am50em]

Is gear 7 sprocket on the correct way around?

[Duck!]

Is gear 7 sprocket on the correct way around?

The spline pattern makes it impossible to fit any sprockets the wrong way around.

In another thread on this forum somewhere I remember someone talking about 10sp shifters, 10sp MTB cassette and a 9sp MTB rear derailleur (I think), something about a 9sp MTB derailleur having the same pull as a 10sp road.

That would have been me.

Now I am not sure if there is a long cage RD for the Tiagra 4600 series groupset

You already have the long version; in the context of road derailleurs, "medium" and "long" cage are the same thing. True long cages are the exclusive domain of MTB derailleurs, and they will give you the capacity to run up to a 36T sprocket without hanger extenders, in conjuction with a triple-ring crank.

[10speedsemiracer]

In another thread on this forum somewhere I remember someone talking about 10sp shifters, 10sp MTB cassette and a 9sp MTB rear derailleur (I think), something about a 9sp MTB derailleur having the same pull as a 10sp road.

That would have ben me.

So, and bear with me here, would a 9sp Shimano Alivio Shadow rear mech for example solve this configuration ? And would it then also run without the Wolftooth hanger extender (maybe shortening the chain a bit) ? From what I can tell so far, OP has Tiagra 10sp brifters, 50-34 front on the Tiagra front mech and a Sunrace 11-40 MTB cassette...

[Duck!]

In another thread on this forum somewhere I remember someone talking about 10sp shifters, 10sp MTB cassette and a 9sp MTB rear derailleur (I think), something about a 9sp MTB derailleur having the same pull as a 10sp road.

That would have been me.

So, and bear with me here, would a 9sp Shimano Alivio Shadow rear mech for example solve this configuration ? And would it then also run without the Wolftooth hanger extender (maybe shortening the chain a bit) ? From what I can tell so far, OP has Tiagra 10sp brifters, 50-34 front on the Tiagra front mech and a Sunrace 11-40 MTB cassette...

In theory no, because officially the derailleur is limited to a maximum sprocket of 36T. But! the Shadow type derailleurs do have a fair bit of tolerance to go beyond the official maximum, largely due to having a positive stopper against forward movement of the derailleur body on the B-pivot, so a 40T can be made to work without extended mounting.

As hinted at previously, All Shimano stuff (excluding internal hub gear systems) up to 9-sp, plus road 10-sp. with the sole exception of current-series 4700 Tiagra uses a common cable pull/leverage/actuation ratio (1.7:1, for anyone interested, meaning the derailleur moves 1.7mm for every 1mm of cable pulled by the shifter), so any combination of shifter and derailleur from those families will work, all that needs to match is the number of gears in the shifter and cassette. MTB 10-sp, road 11-sp. (plus 4700 Tiagra) and MTB 11-sp. each use unique cable pull ratios, so can only be mixed within their own families. So yes, a M4000 Alivio Shadow derailleur will work perfectly well with 4600 Tiagra shifters.

The curious thing is that the OP's shifting problem only seems to be at one shift point, which perhaps suggests there may be a kink in the cable causing it to bind a bit at that point. My original thought had been that due to the slope of the cassette (the line drawn across the tips of the sprockets) being steeper than the derailleur path, which is optimised for a tighter-range cassette, with the derailleur being lowered to clear the large sprocket, as it's shifted to the smaller sprockets the gap between the sprocket and top jockey wheel increases, allowing the chain more room to flex rather than shift gear, but that would become more progressive the further out on the cassette you go, not confined to one position.

[Aushiker]

The curious thing is that the OP's shifting problem only seems to be at one shift point, which perhaps suggests there may be a kink in the cable causing it to bind a bit at that point.

I have a similar problem on my Salsa Mukluk but in my case it is a SRAM setup. Interestingly I replaced the inner cable and that improved the shifting but didn't solve it 100%. I am now thinking it might be the outer cable given your comments

The other initial thought I had was the cluster was not put back together properly after a wheel build [long story short the cluster "fell apart" at the wheel builders and initially there was a "spare" spacer]. As it has a OneUp 42t sprocket and I was not 100% sure initially where the spacer went that didn't help with the problem solving.

Interestingly the shifting problem followed the wheel build but that may just have been concidencene.

[zaxatron]

Is gear 7 sprocket on the correct way around?

Correction: I had my gear numbering wrong.

I am counting my gear as 10 being the smallest sprocket (high gear 11 tooth) in the rear cassette going to 1 being the largest sprocket (low gear 40 tooth).

I have the problem occurring (not always, sometimes it works fine) when going from gear 5 to gear 4 and vice versa.
Therefore gear 5 would be the sprocket with 24 tooth (11-13-15-18-21-24-28-32-36-40) going to gear 4 the sprocket with 28 tooth.

Can the shifter be causing the problem?

The other day I bought some good quality Shimano cable outer for the brake and gear cables.
Soon I will be replacing the cable outer and the cable themselves. I will be using teflon coated staineless steel cables.

Regards

Zaxa

[am50em]

Is gear 7 sprocket on the correct way around?

I am counting my gear as 1 being the smallest sprocket (high gear 11 tooth) in the rear cassette going to 10 being the largest sprocket (low gear 40 tooth).

I have the problem occurring (not always, sometimes it works fine) when going from gear 6 to gear 7 and vice versa.
Therefore gear 6 would be the sprocket with 24 tooth (11-13-15-18-21-24-28-32-36-40) going to gear 7 the sprocket with 24 tooth.

Can the shifter be causing the problem?

The other day I bought some good quality Shimano cable outer for the brake and gear cables.
Soon I will be replacing the cable outer and the cable themselves. I will be using teflon coated staineless steel cables.

Usual convention is low numbers are the low gears and higher numbers are high gears.
And I think you mean gear 6 - 24 tooth and gear 7 - 28 tooth?
Are gears 6 and 7 on the same spider carrier? In which case cannot be any missing/incorrect spacers.
No bent teeth? other defects?

If shifter works fine for all the other gears i.e. moves the derailleur the correct amount, hard to see why this one particular gear change problematical. As others suggested it will be interesting to see if new (outer) cables solve the problem.

[zaxatron]

Is gear 7 sprocket on the correct way around?

I am counting my gear as 1 being the smallest sprocket (high gear 11 tooth) in the rear cassette going to 10 being the largest sprocket (low gear 40 tooth).

Thank you for the correction I numbered my gears in reverse. I will correct the original post.

[am50em]

Depending on exact model, the specs say they have either 6 sprockets on two spiders or 5 sprockets on two spiders.

Code: Select all

individual       spider A    Spider B
11 13 15 18      21-24-28    32-36-40
11 13 15 18 21   24-28       32-36-40
11 13 14 18 21   24-28-32    36-40

For all of them 24-28 is part of a single spider, so barring a manufacturing fault, the cassette should not be the problem.