XX1 strange issue.... upshifts on back pedal

[Jaredp]

Hey Guys

Just doing some maintenance on the bike whilst I am laid up.

I replaced the shift cable, BB and re-greased the jockey wheels.

I have an odd problem, In the largest cog right through to second from bottom everything is normal, up shifts/ downshifts runs smoothly and when you back pedal the bike just free spins as normal.

In the top two gears (smallest cogs) as soon as you back pedal the cassette picks up a link and up shift the the next largest gear.

I have had a look at cable tension, checked the Dropout alignment, and adjusted the limiter screw. It weird.

I re assembled the Crank with all the same bits in all the same order. And then re assembled with an extra spacer on the drive side. This has made it better. but its still there.

Has anybody else come across this.

Duckmiester?????? HELP :noidea:

 

[link1896]

Hey Guys

Just doing some maintenance on the bike whilst I am laid up.

I replaced the shift cable, BB and re-greased the jockey wheels.

I have an odd problem, In the largest cog right through to second from bottom everything is normal, up shifts/ downshifts runs smoothly and when you back pedal the bike just free spins as normal.

In the top two gears (smallest cogs) as soon as you back pedal the cassette picks up a link and up shift the the next largest gear.

I have had a look at cable tension, checked the Dropout alignment, and adjusted the limiter screw. It weird.

I re assembled the Crank with all the same bits in all the same order. And then re assembled with an extra spacer on the drive side. This has made it better. but its still there.

Has anybody else come across this.

Duckmiester?????? HELP :noidea:

Definitely not right. When pedaling normally, does chain drop into lowest cog quickly?

What position at the rear makes your chainline straight? I do all my maintenance in the stand spinning cranks backwards with chain on the smallest cog, never a drama. My straight chain line on an Epic World Cup is about 6th gear

No dodgy links? What chain and speed link? No bent teeth on cassette?

 

[JTmofo]

Set up Hi and Lo limits again, and tune again as normal.

I get this sometimes when adjustment is needed. The barrel adjuster should get you back on track, once the hi and lo are set right.

 

[The Duckmeister]

Derailleur setup has fuck-all to do with it, because when backpedalling the chain goes through the derailleur after passing over the cassette.

Check the cassette is on properly! If that has crept outboard it'll bugger the chainline & cause exactly that problem - causes more deflection in the chain, so it rides up onto the bigger sprocket until you're on a straighter chainline. The same priciple explains why it's got better by moving the chainring out (go too far though & you'll end up with it dropping when you backpedal on the other end of the cassette.

If you spend a lot of time riding on that end of the cassette (indicating your chainring is too small), those few sprockets could be more worn & developing burrs that will snag the chain as it goes past.

 

[JTmofo]

Derailleur setup has fuck-all to do with it, because when backpedalling the chain goes through the derailleur after passing over the cassette.

Check the cassette is on properly! If that has crept outboard it'll bugger the chainline & cause exactly that problem - causes more deflection in the chain, so it rides up onto the bigger sprocket until you're on a straighter chainline. The same priciple explains why it's got better by moving the chainring out (go too far though & you'll end up with it dropping when you backpedal on the other end of the cassette.

If you spend a lot of time riding on that end of the cassette (indicating your chainring is too small), those few sprockets could be more worn & developing burrs that will snag the chain as it goes past.

Incorrect. Even though the chain passes over the cassette first on back pedalling, the RD has direct effect on the chain positioning and subsequently the cog selection.
You will find that the ramps and tooth profiling on the cassette teeth are designed to aid shifting on positive pedal stroke, and maintain the cog selected.

If your RD is not adjusted properly you will slips through some cogs on your cassette when back-pedalling.

I'm not saying this Is the issue.... but I'm glad The Duckmeister is 100% sure is has "fuck all" to do with it.

On a side note, running a 10 sp chain on 11sp also doesnt help the situation, even though is only a miniscule different in link width (if this is the case with the OP set up) or gummed up jockey wheels.

 

[The Duckmeister]

Incorrect. Even though the chain passes over the cassette first on back pedalling, the RD has direct effect on the chain positioning and subsequently the cog selection.
You will find that the ramps and tooth profiling on the cassette teeth are designed to aid shifting on positive pedal stroke, and maintain the cog selected.

NOT when the system is operated backwards. I just did a quick check on my XT 3x10-equipped bike (nice extreme chainlines on hand :wink: ) Small ring/small rear there is not surprisingly some slight chain pickup when backpedalling. Alteration of the derailleur position results in the chain jamming between the cassette and the derailleur. There is no effect on how the chain rides on the cassette until there is significant drag induced by the chain unshipping from the upper jockey wheel.

Changing chainline by shifting to the bigger rings progressively improves how the chain backpedals, until the opposite extreme (big/big) is reached, and the chain begins to drop from the big sprocket.

Your second note regarding tooth profiling and ramping actually counters your argument.

Chainline is the problem unless there is significant component wear in play.

 

[schred]

I thought this was normal that a few gears have sh1tty chainline when you have an 11sp cassette and a single chainring, which is most noticeable pedallying backwards.

 

[Jaredp]

Cheers for the responses guys, when I get home I will have a look at all options suggested.

Stupid question though.... I know Shimano have a direction to their chains (replaced loads and always checked the manual) I cant see anything about it in the SRAM manuals. They appear to be directionless????? True or not Duck?

 

[The Duckmeister]

Correct, SRAM chains are not direction-specific.

 

[Ivan]

Cheers for the responses guys, when I get home I will have a look at all options suggested.

Stupid question though.... I know Shimano have a direction to their chains (replaced loads and always checked the manual) I cant see anything about it in the SRAM manuals. They appear to be directionless????? True or not Duck?

Uh oh. Shimano are directional? Shit......

 

[Minlak]

Cheers for the responses guys, when I get home I will have a look at all options suggested.

Stupid question though.... I know Shimano have a direction to their chains (replaced loads and always checked the manual) I cant see anything about it in the SRAM manuals. They appear to be directionless????? True or not Duck?

Correct, SRAM chains are not direction-specific.

Uh oh. Shimano are directional? Shit......

Shimano you should be able to read the words Shimano on the chain when fitted
SRAM and KMC don't matter however I have noticed after some use outing them on be same way feels nicer.

 

[Mitch243]

Adding to the chain of people saying normal/not a problem.

Derailleurs work by guiding the chain over the ring.
The derailleur carriages along its path to put the chain into the right spot.

When you back pedal the chain will try to follow the path as close to its source (the chainring).

 

[Flow-Rider]

Short chainstays, new stiff chains on large numbered speed geared cassettes. I haven't seen too many of these bikes that don't drop down into the next gear when you back pedal but it's normally in the big to big sprocket. 29ers seem to have less problems because the chain stays are longer, the chain angles are less and has some length to twist in.

 

[bikeyoulongtime]

any resolution Jaredp? I'm curious...

no such issues on my X01, the chainline is awful at the top and bottom of the cassette but it backpedals happily in any gear. longish stays (435mm), 27.5" bike, 32T up front.

*some* shimano chains are assymetrical. Minlak's general guide is good - printed side out, you should be allright. It'll shift terribly if its on the wrong way. If in doubt, RTFM.

 

[The Duckmeister]

*some* shimano chains are assymetrical.

Those ones being all MTB 10 & 11-sp, and 2nd-gen road 10-sp. All others are symmetrical (non direction-specific).

 

[Jaredp]

Ok, well I decided this was good a time as any to service the rear hub. So I removed and cleaned the cassette, serviced the free hub body and bobs me mums brother it's fixed.

Given the cassette was pretty darn clean to begin with I would have to give it to Duck in this case. I reckon the cassette had moved on the freehub. It was the first time I had removed an XD type cassette.

For those that aren't familiar with XD type cassettes, the cassette and lock nut are one. Basically making the cassette a big nut. It was tight, but once cracked it just came off. I cleaned the threads on the freehub and the gradual increase in resistance till eventually torqued would suggest the cassette was loose but grime had stuck it in place.

Well that's that. For anyone else having the issue later on. Remove cassette, clean the freehub and replace... See how yago.

Thanks for the advice fellas.

BTW... For an all round trail bike. I will be going back to 2x setup in the future. When this groupo finally wears out. Back to XX or shimano equiv, I truly don't see the benefit In 1x for a trail bike that will be asked to take on such varied terrain.

On a dedicated XC race machine and descending Enduro /DH. Yep I get it. Distinct advantage here. But my bike will be shuttling one weekend and doing 75-100km XC rides the next. I ask it to climb steep as heck stuff one week and be a downhill bike the next.. It's just not versatile enough for that. Just my 2c anyway.

 

[Warp]

BTW... For an all round trail bike. I will be going back to 2x setup in the future. When this groupo finally wears out. Back to XX or shimano equiv, I truly don't see the benefit In 1x for a trail bike that will be asked to take on such varied terrain

You will be bbq'd by the One-Ring brigade.

I have tried both, currently 1X. Still on the fence. Both systems have their virtues and it all comes to end-user.
I wish I had shaitloads of money to have one bike with 1X and one with XTR Di2.

 

[link1896]

Jaredp, did the loose cassette not creak like a bitch? I found if mine wasn't greased well and torqued to 40Nm it creaked like a bitch on climbs. I've grown to love 1x11 but Christ did my legs hurt to begin with. My average cadence over an hour is now around 100. 1x is not for everyone, and I probably need to buy a larger and smaller chainring for special events. Have not dropped a chain once yet.

 

[Jaredp]

Jaredp, did the loose cassette not creak like a bitch? I found if mine wasn't greased well and torqued to 40Nm it creaked like a bitch on climbs. I've grown to love 1x11 but Christ did my legs hurt to begin with. My average cadence over an hour is now around 100. 1x is not for everyone, and I probably need to buy a larger and smaller chainring for special events. Have not dropped a chain once yet.

To be fair, it didn't creak. But man was it stuck hard. It felt tight as I had to put massive amounts of pressure on the wrench to get it off. But when it cracked open it just cam off in a few turns.

I have dropped a chain with this on a pretty small step down once and a few reports from journo's would suggest they have had similar experiences. I have run a small chain guide off of the stumpy FSR for ages now with no further issue. I like 1x and my XC bike I use for racing is definately benefiting. But it's just not a diverse system for "every-terrain-any-time" mentality. Changing chainrings depending on the weekend's acttivities is not really me. I just want get on and ride when it's just about fun... On race day with a race bike. That's different.