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Discussion Starter · #1 ·
I have a new Ibis Ripmo V2 with 12 speed XT with 28t up front and 10-51 cassette. Size XL. When mashing under load in the 28x10 combo the chain skips and clunks, like it’s trying to shift up to the 12t and then falling back onto the 10t. Otherwise, every other combo is smooth and flawless.

This is my first full suspension bike. I have many years experience home wrenching on Shimano 9, 10 and 11 speed drivetrain on hard tails and road bikes. I think I understand hi-low, b screw, hangar alignment, etc, and all that seems to be just right on this bike. I also looked inside the hydra hub and lubed it with Dumonde. It’s fine. I’m starting to think that this problem is being caused by frame flex. Is that even a thing on the Ripmo? I’m not some heavyweight who breaks crank arms or anything like that. I’m 185 lbs.

I guess I’m looking for input about what I might be missing in trying to dial this in on a full suspension bike, and the Ripmo especially.

Any thoughts would be appreciated.


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Discussion Starter · #4 ·
Okay. Thanks for the input. I gather from the lack of response regarding flex that flex is not a thing. Just figured I’d throw it out there.

So, last night I watched some installation videos and read over the dealer manual on derailleur installation. Then I went through everything from scratch and noticed:

1. The chain is too short. Using the Shimano wrap method, I only count 3 links where there should be at least 5.

2. The b-screws was not correct. I had it set up eyeballed to the cassette as I am accustomed to doing on 11 speed and earlier. I turned it to tighten the gap so it matched the line on the cage. It was off by approx 3-4 mm too much gap.

3. I cleaned and lubed the chain.

Results:

I took it for a spin this morning and the skipping is gone! I did some heavy mashing with no skipping problem at all. Nothing but smooth shifting that I’ve come to expect from Shimano.

The problem must have been the b-screw. I’m surprised that this 3-4 mm tolerance made such a big difference, as I’ve found Shimano to be very forgiving, but then again I can see why it matters.

I’m a little concerned about the short chain, but there does seem to still be just enough capacity in the 28x51 combo even with sag. Would you guys replace or just to be sure?


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Discussion Starter · #6 ·
Glad you got it fixed. If you are mashing climbs in the 10t cog, it seems that you could benefit from a bigger chain ring.
Lol. No, it's not like that. I want the 28t so I can spin in relative comfort up some long steep fire roads. I much prefer to be able to spin a high cadence, and I'm relatively weak so even on a 30x51 I tend to struggle a bit going up long steep roads. That gives up some on the high end, as you know. The mashing comes on flat ground or gentle rolling terrain where I just put it in the 28x10 and mash over the rollers to keep my speed up as much as possible.

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If you are mashing climbs in the 10t cog, it seems that you could benefit from a bigger chain ring.
My first thought Was also relaxed to the 28t smalish ring. But I'm running a 30t oval and do not have any problems. From your experiance I can be happy that it works so well because I also did not read any of the instructions and have set it up like I felt it should be.

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Discussion Starter · #10 ·
I really need to weigh mine. But I did weigh the demo I was riding. It's a Ripmo V2 size XL with XT build and fox performance DPX2, fox performance 36 with Grip damper, and ibis carbon rims and ibis brand hubs. It weighted 30.77 lbs. Here's the demo bike on the scale:



Mine is the 2021 model with i9 wheels and factory X2. The X2 is heavier than the DPX2 but the i9 hubs are lighter than the ibis hubs so it should be pretty close to the same weight. I'll try to remember to weigh it and give you the exact figure. But I must say it's an incredible bike. I am blown away by how well it does everything. You're lucky to have one on the way. Enjoy!



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My large custom build with XTR drivetrain, Fox Factory suspension and longest dropper, OneUp handlebar and stem but heavy Dominion brakes and Specialized tires weighs 30.5lbs. My wheelset is also fairly light at 3.9, so I wonder where the additional weight might be hidden. Are you weighting with or without pedals?

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My prior pic/post was weight without pedals. The weight with pedals is 31.45 lbs.
Seems to be more plausible now. I have the Hayes brakes, PD-M9120 pedals and an easy-frame cover which does also add some grams. XTR shifter and derailleur aren't really lighter than XT.
Thanks for taking another pic!

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Okay. Thanks for the input. I gather from the lack of response regarding flex that flex is not a thing. Just figured I'd throw it out there.

So, last night I watched some installation videos and read over the dealer manual on derailleur installation. Then I went through everything from scratch and noticed:

1. The chain is too short. Using the Shimano wrap method, I only count 3 links where there should be at least 5.

2. The b-screws was not correct. I had it set up eyeballed to the cassette as I am accustomed to doing on 11 speed and earlier. I turned it to tighten the gap so it matched the line on the cage. It was off by approx 3-4 mm too much gap.

3. I cleaned and lubed the chain.

Results:

I took it for a spin this morning and the skipping is gone! I did some heavy mashing with no skipping problem at all. Nothing but smooth shifting that I've come to expect from Shimano.

The problem must have been the b-screw. I'm surprised that this 3-4 mm tolerance made such a big difference, as I've found Shimano to be very forgiving, but then again I can see why it matters.

I'm a little concerned about the short chain, but there does seem to still be just enough capacity in the 28x51 combo even with sag. Would you guys replace or just to be sure?

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Glad you got it solved! To answer your question about chain length, IME Ibis bikes do need shorter than what the manufacturer calcs would say, otherwise you get excessive slack in the highest gear (esp with an oval chainring). Sounds as if you did this, but shift to the lowest gear and compress the suspension fully to account for chain growth: the derailleur will be extended almost all the way but still able to run. My thinking here is that you'll never bottom the suspension while in that gear, so it's acceptable to have it set up at such an extreme. That technique for chain sizing has been successful for me on numerous Ibis bikes over the years. Good luck!
 

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I'm a little concerned about the short chain, but there does seem to still be just enough capacity in the 28x51 combo even with sag. Would you guys replace or just to be sure?

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I'd let the air out of the shock and bottom it out. If there's enough chain at that point, I wouldn't replace it. If there's not enough chain at that point (unlikely, it seems) then I'd put on a longer chain.
 

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Discussion Starter · #17 ·
Glad you got it solved! To answer your question about chain length, IME Ibis bikes do need shorter than what the manufacturer calcs would say, otherwise you get excessive slack in the highest gear (esp with an oval chainring). Sounds as if you did this, but shift to the lowest gear and compress the suspension fully to account for chain growth: the derailleur will be extended almost all the way but still able to run. My thinking here is that you'll never bottom the suspension while in that gear, so it's acceptable to have it set up at such an extreme. That technique for chain sizing has been successful for me on numerous Ibis bikes over the years. Good luck!
Thanks. I share your thinking-I don't see how I'd ever bottom out while I'm using the 28x51. I appreciate you sharing your experience with this. I'll let the air out and check it. Thanks!

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Discussion Starter · #18 ·
I'd let the air out of the shock and bottom it out. If there's enough chain at that point, I wouldn't replace it. If there's not enough chain at that point (unlikely, it seems) then I'd put on a longer chain.
Thanks. I wish I had thought of this. Shows how little I know about full suspension bikes. I'll give it a try and save my new chain for the future. As a side observation, I couldn't find an XT 12 speed chain on amazon. People were hocking 10 speed chains for outrages prices. I feel lucky to have found it in stock at Jenson USA.

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Thanks. I wish I had thought of this. Shows how little I know about full suspension bikes. I'll give it a try and save my new chain for the future. As a side observation, I couldn't find an XT 12 speed chain on amazon. People were hocking 10 speed chains for outrages prices. I feel lucky to have found it in stock at Jenson USA.

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Understandable. When I find something like that, I get 2 of them. I have a few bikes that I'm responsible for (2 of mine, my wife's and my son's) so things seem to come up unexpectedly and it's nice to have some spares.
 
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