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135 mm frame - 1x11 coversion - chain line issue

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gs12

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Discussion starter · #1 · (Edited)
hey, I know the 1 x conversion topic has been flogged to death, but after few evenings I'm running out of ideas.

I upgraded my spare old hardtail from 3x10 to 1x11 using new Shimano Deore M5100 components and narrow-wide chain ring.
As far as my internet search tells me, that should work well (example here: https://www.mtbr.com/threads/ive-been-told-it’s-impossible…135mm-1x11.1203305/ )

After installing all new components and lot of tuning, the shifting is incredibly rough at the top range, the 51t cog is unusable, it looks as the derailuer cage can't handle the chain line: with the clutch ON the chain slips of the bottom pulley and rubs agains the cage. With clutch OFF it kind of works but still grinds pretty badly and I feel I'm missing something obvious.

Additional info:

Frame specs are here:
www.santacruzbicycles.com

Highball 1

Santa Cruz Bicycles is dedicated to making the world's best mountain bikes. From the World Championship-winning V10 to the beloved Tallboy, we make bikes for people who live to ride.
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chainline: 50 mm
rear stays: 135 mm

component list:
  • Deore CS-M5100 11-51T 11-Speed Cassette
  • Deore Shadow RD-M5100-SGS 1x11 derailleur
  • Deore SL-M5100 Rapidfire Plus 11 Speed shifter
  • Deore XT Sil-Tec 126L 11spd Chain
  • Wolftooth 34t Drop Stop B chainring
  • Shimano XT FC-M780 crankset (from original 3x10 setup)
I measured the actual chainline of the NW chainring and get 49.7 mm. My next step is to move the chainring inboard by adding spacers and/or removing the bottom bracket spacer.
Before I do that I wanted to check if this is chainline issue or am I doing something else wrong, such as component mismatch.

EDIT: when I installed new chain as per Shimano instructions (quick link + 4 links), the derailleur was so much forward I couldn't even set the B gap correctly, this improved by adding 2 links to chain length. Should I add more links?
Any suggestions apart from this? Thanks
 
Discussion starter · #5 · (Edited)
Thanks for replies, limits crews are set up correctly as well as the B Gap. NW chain ring is mounted where the middle ring used to be with no spacers. adding 2 mm spacers seems to improve shifting.

What is confusing me is the fact that I could used the middle on 3x9 set up across the entire casette range, I believe the 10 and 11 speed casettes are the same width (or very close), making me think it may be something other than chainline.

I tried taking pictures last night but they did not show the problem well. I will post some later today. Thanks
 
Discussion starter · #6 ·
I'm attaching few photos: side view, chain line from top and bottom (bike upside down) and detail of bottom pulley wheel, showing the chain is off the pulley and rubbing against the cage. My next step is to put 2 mm spacers between the crank and chain ring and see if that makes a difference
Image


Image


Image


Image
 
#8 ·
how long are your chainstays? I have essentially the identical setup, with the exception that the crank is the deore triple (M590) rather than XT, but it's the same generation and pretty much the same design. I'm using a raceface NW chainring in the middle position with no spacers, and everything works well. My chainstays are a fairly long 445 mm, though. If yours are a lot shorter, that could be enough to make the angles worse.
 
#10 ·
On my 3x to 1x conversion, I added the chainring to the 64 BCD and a bash guard on the 104 BCD. The chainring had to be slightly smaller for clearance. It looks like your chainring needs to move inboard. Are the pictures you post already with the 2mm spacers installed on the chainring?
 
#11 ·
driven916 said:
It looks like your chainring needs to move inboard.
Click to expand...
Agreed. Maybe this can't be done on a 135mm frame.
But it sure looks like the chain angle is the culprit.
Go to a smaller ring (farther inboard) + smaller cassette (eg 46t) to alleviate the situation?
Hopefully doing both would leave you with a compatible gear range.
=sParty
 
#12 · (Edited)
The real solution is get a new chainring with 64 BCD. Edit: the chainring spacers should work, too, I guess I thought you already tried that, it would be easiest.

The janky way to do it is remove the BB spacer on the drive side. I think there is only one spacer, right? If there are two, just take out one. If the chainring you have doesn't hit the chainstay at this point, install the cranks and put an O ring around the threads of the preload "bolt" so that you can still get some preload without it bottoming out. Then space out your driveside pedal with some pedal washers equal in width to the bb spacer you took out.

I have done this to my gravel bike with that crank to get it to work with the 130mm axle spacing.
 
Discussion starter · #14 ·
thanks all for replies and suggestions
the chainstays are 430 mm long and I suspect that Andrew is right in saying this makes it worse.

I have temporarily put spacers between chain ring and crankset just to eye ball the chain line and need to do it properly on the weekend.
Removing the BB spacer also crossed my mind, I think I have enough clearance. I was going to move it to left side, effectively shifting BB and pedals 2.5 mm to the left. I know it may not be ideal solution but this is a spare bike that I don't ride too often so I want to try this before buying more parts. (I'm a cheap ar$e)

Quick calculation tells me that right now the chain is about 10 mm outward from the center for the cassette. I hope 2 mm spacers will make it work. If I have to also move the BB spacer than the chain will almost in the middle (0.5 mm off the center line).

Cheers
 
#15 ·
I too upgraded my older bike(2009 Turner Sultan) with a 135 frame/hub, I went from 3x9 to 1x12 since the 3x9 was completely worn out. With all the new take off components people are dumping for dirt cheap, I went with Sram, nx 11-50 cassette, gx RD/shifter, old x01 crank I had laying around and DUB BB. I used a 6mm offset chainring which achieved a perfect 49mm CL. Shifts smooth and perfectly in all gears, backpedals without issue in 1st.

Bottom line, I'd think the configuration you have should work, though the pic from the bottom looks line an extreme CL. Are you sure the CL is 49.7? Some hubs require a spacer behind the cassette, how close is high gear to the DH?
 
#16 ·
gs12 said:
I have temporarily put spacers between chain ring and crankset just to eye ball the chain line and need to do it properly on the weekend.
Removing the BB spacer also crossed my mind, I think I have enough clearance. I was going to move it to left side, effectively shifting BB and pedals 2.5 mm to the left. I know it may not be ideal solution but this is a spare bike that I don't ride too often so I want to try this before buying more parts. (I'm a cheap ar$e)
Click to expand...
Nice. (y)
Personally I'd recommend inboarding your chainring as far a possible (min chainline.)
Whatever that may be.
The big cogs present the worst of chainline problems.
Good luck!
=sParty
 
#17 · (Edited)
As others have asked, I'd question if the chainline is really ~50mm. If the chainring isn't offset, the chainline will probably be 52-53mm. Ideally it'd be ~46mm, and only limited by how much rub there was between the 11t and the next cog up the cassette.

Edit, I'm running a 1x12 on a 135 frame with a chainline of ~49mm. No issues.
 
#19 ·
gs12 said:
thanks all for replies and suggestions
the chainstays are 430 mm long and I suspect that Andrew is right in saying this makes it worse.

I have temporarily put spacers between chain ring and crankset just to eye ball the chain line and need to do it properly on the weekend.
Removing the BB spacer also crossed my mind, I think I have enough clearance. I was going to move it to left side, effectively shifting BB and pedals 2.5 mm to the left. I know it may not be ideal solution but this is a spare bike that I don't ride too often so I want to try this before buying more parts. (I'm a cheap ar$e)

Quick calculation tells me that right now the chain is about 10 mm outward from the center for the cassette. I hope 2 mm spacers will make it work. If I have to also move the BB spacer than the chain will almost in the middle (0.5 mm off the center line).

Cheers
Click to expand...
You can move the spacer to the other side, you will just have your right pedal 5mm inboard from your left pedal and need 5mm of pedal spacers to equalize it, which is a lot. Of course, you don't have to equalize it if you don't notice it, or you could move your cleats around to compensate if you don't use your shoes on other bikes.
 
#20 ·
forkboy said:
I tried a similar 1x setup and had similar problems with a 50t. No issues with a 42t, so I just got a smaller 1x chain ring to hit my ratio.
Click to expand...
I've got 11 speed on a few bikes now, but only the 46t and had no issues. And one bike has shorter stays than OP at 419mm. It may just be that the big cog is a bridge too far. Which is not ideal given it's been purchased. Agree with the advice of trying to get the chainring more inboard. I spend the most time in the granny end of the cassette so don't mind having the chainring biased that way. If you're doing big kms on the flat it might be more of an issue.
 
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