More Praxis Chain Drop Questions

[Cycle]

Hi,

I am new to the forum and it looks like there is a LOT of great info here. My wife has a 2020 Creo and it had been working well for hundreds of miles, but now the chain is dropping off the front chainring on EVERY ride. Every ride = 4 in a row so far ;-) I recently got a 2021 EVO and ridden on each of those rides and my chain did not drop, or falter in any way. I see a lot of posts about the Praxis chain drop issue and it seems like the Gararbuk chainring may fix it, but their website says it could be 15 - 30 days for a chainring!!

General question: Has anyone else experienced good performance, then suddenly started to drop the chain?

Here's what I have checked:
- Is chain aligned on chainring correctly? Yes, matches the etching on the inside of the praxis chainring. I taped a copy to the outside since it was dropping so much!!
- Is the clutch on? Yes, for all except one instance. I swapped tires for her and forgot the clutch once
- Chain wear? chain is good
- Derailleur alignment? check, it is straight and I actually took the wheel off and used the Park hangar alignment tool. Hangar is good and derailleur when mounted is straight
- Shifting is adjusted and smooth
- Mounted the Specialized chain guide before the last ride and chain still dropped/jammed in the chain guide

What I noticed after this weeks rides is what seems to be excessive, or abnormal wear on the Praxis ring. The entire outside, of the outside tooth is shiny. Not worn yet, but definitely heavy rubbing (see pics).

Any ideas or suggestions?

!

Thanks!

 

[MacCrackin]

Hi,

I am new to the forum and it looks like there is a LOT of great info here. My wife has a 2020 Creo and it had been working well for hundreds of miles, but now the chain is dropping off the front chainring on EVERY ride. Every ride = 4 in a row so far ;-) I recently got a 2021 EVO and ridden on each of those rides and my chain did not drop, or falter in any way. I see a lot of posts about the Praxis chain drop issue and it seems like the Gararbuk chainring may fix it, but their website says it could be 15 - 30 days for a chainring!!

General question: Has anyone else experienced good performance, then suddenly started to drop the chain?

Here's what I have checked:
- Is chain aligned on chainring correctly? Yes, matches the etching on the inside of the praxis chainring. I taped a copy to the outside since it was dropping so much!!
- Is the clutch on? Yes, for all except one instance. I swapped tires for her and forgot the clutch once
- Chain wear? chain is good
- Derailleur alignment? check, it is straight and I actually took the wheel off and used the Park hangar alignment tool. Hangar is good and derailleur when mounted is straight
- Shifting is adjusted and smooth
- Mounted the Specialized chain guide before the last ride and chain still dropped/jammed in the chain guide

What I noticed after this weeks rides is what seems to be excessive, or abnormal wear on the Praxis ring. The entire outside, of the outside tooth is shiny. Not worn yet, but definitely heavy rubbing (see pics).

Any ideas or suggestions?

!View attachment 132580

Thanks!

I'd replace the chain - it's noted GOOD - but if certain tests were done - it's more than likely stretched
to the point, that it no long fits the pitch of the sprockets, and more than likely will crawl off.
The easiest test is wrap the chain around the sprocket almost full circle tight as possible,
it should be impossible to pull any portion of the chain away from circle of sprocket.
If any portion of chain is floating offset from the teeth of sprocket. It's Junk.
Best point of test is 180 from free ends of chain.
Prolonged use like this will only destroy the sprockets as well.

Once the new chain is put to the same test, it will become quite clear.
One could lay them side by side, and see the pins of chain no long match a foot or two pulled tight.

 

[Allan47.7339]

Does she have a habit of backpedaling? I had a chain drop recently doing that under the same conditions. It's probably due to the clutch in the chain ring motor system.

edited to add:

Usually I am going down hill at speed semi-coasting where the gearing has not caught up with the speed and I coast before starting to change gears.

 

[MacCrackin]

Does she have a habit of backpedaling? I had a chain drop doing that under the same conditions. It's probably due to the clutch in the chain ring motor system.

Oh Sure - never dawned on me - First Clown Clothing,, Now Clown Pedaling @!

 

[Stefan Mikes]

I'd replace the chain - it's noted GOOD - but if certain tests were done - it's more than likely stretched
to the point, that it no long fits the pitch of the sprockets, and more than likely will crawl off.
The easiest test is wrap the chain around the sprocket almost full circle tight as possible,
it should be impossible to pull any portion of the chain away from circle of sprocket.
If any portion of chain is floating offset from the teeth of sprocket. It's Junk.
Best point of test is 180 from free ends of chain.
Prolonged use like this will only destroy the sprockets as well.

Once the new chain is put to the same test, it will become quite clear.
One could lay them side by side, and see the pins of chain no long match a foot or two pulled tight.

You ride a Creo or are just talking?

 

[MacCrackin]

You ride a Creo or are just talking?

Just from many years of tech servicing motorcycles.
Nothings changed since chain was invented.
____________________________________________________
Standard motorcycle chain. Obviously bike chain's durability is quite limited.
For example - best chain made, well maintained lasts 5000 miles before pitch no longer fits sprockets.
Same chain - lucky if it makes 1000 miles if not serviced.
Best O-Ring chain lasts 20,000 miles, but it's 2-3 times more. After several thousand customers,,
those are the best numbers.
No One will ever be able to come up with those figures,, just making it up out of the blue.
Any bicycle tech after 20 years will have the numbers for bike chain that are average after thousands serviced as well. Those numbers listed will be found in the end as to how well it was cared for in general,, regardless road or dirt, right? Then steel vs aluminum. E-Bike or not.
Probably good chance steel is 4 times longer wear, or showing wear.
When teeth start to tip over bent,, some may not take the hint,, some are fussy. Some whine broken down,
some never break down, but that's not by accident, this will never change. No different than Aircraft Tech,,
when you board your flight, Passengers never give it a thought what went on all night before to make sure 350,000 lbs of industrial nonsense gets them on their way, but they signed their name on every thing they touched, they are the fussiest of creatures betting their life on it.
L-1011's,, no one has built a tougher ship like that ever again, and the ones lucky enough who flew on them
will never forget as well. As well as the ones picked to service them was no accident. I was very fortunate.
So No Worries getting mad,, if it makes the outcome flawless,, everyone wins.
Cheers

 

[MacCrackin]

If I recall correctly, mschwett was talking about indexing the chain to the ring. There's marking on it. I could be wrong
Could be a simple fix by a new chain and ring.

I need to look closer on that bit of chain tech as well.
Seems I noticed side plates were special tweaked to walk sideways.
Wish that was a tech item bubble when hovering over it for more details.
But this search was a worthy good start - https://search.brave.com/search?q=indexing+the+chain+to+the+ring&source=desktop

This link is a bit more precise - https://search.brave.com/search?q=indexing++chain+to+ring+gear&source=web
Cheers

 

[Stefan Mikes]

Just from many years of tech servicing motorcycles.
Nothings changed since chain was invented.
____________________________________________________
Standard motorcycle chain. Obviously bike chain's durability is quite limited.
For example - best chain made, well maintained lasts 5000 miles before pitch no longer fits sprockets.
Same chain - lucky if it makes 1000 miles if not serviced.
Best O-Ring chain lasts 20,000 miles, but it's 2-3 times more. After several thousand customers,,
those are the best numbers.
No One will ever be able to come up with those figures,, just making it up out of the blue.
Any bicycle tech after 20 years will have the numbers for bike chain that are average after thousands serviced as well. Those numbers listed will be found in the end as to how well it was cared for in general,, regardless road or dirt, right? Then steel vs aluminum. E-Bike or not.
Probably good chance steel is 4 times longer wear, or showing wear.
When teeth start to tip over bent,, some may not take the hint,, some are fussy. Some whine broken down,
some never break down, but that's not by accident, this will never change. No different than Aircraft Tech,,
when you board your flight, Passengers never give it a thought what went on all night before to make sure 350,000 lbs of industrial nonsense gets them on their way, but they signed their name on every thing they touched, they are the fussiest of creatures betting their life on it.
L-1011's,, no one has built a tougher ship like that ever again, and the ones lucky enough who flew on them
will never forget as well. As well as the ones picked to service them was no accident. I was very fortunate.
So No Worries getting mad,, if it makes the outcome flawless,, everyone wins.
Cheers

The point is I own a Vado SL, which is very similar to Creo SL, and the only chain drop there was when the derailleur clutch was off. That's why I asked you if you owned a Creo. Not? Then your verbose wouldn't help the OP very much. He seems to have done everything properly.

 

[Zekeer]

Hi,

I am new to the forum and it looks like there is a LOT of great info here. My wife has a 2020 Creo and it had been working well for hundreds of miles, but now the chain is dropping off the front chainring on EVERY ride. Every ride = 4 in a row so far ;-) I recently got a 2021 EVO and ridden on each of those rides and my chain did not drop, or falter in any way. I see a lot of posts about the Praxis chain drop issue and it seems like the Gararbuk chainring may fix it, but their website says it could be 15 - 30 days for a chainring!!

General question: Has anyone else experienced good performance, then suddenly started to drop the chain?

Here's what I have checked:
- Is chain aligned on chainring correctly? Yes, matches the etching on the inside of the praxis chainring. I taped a copy to the outside since it was dropping so much!!
- Is the clutch on? Yes, for all except one instance. I swapped tires for her and forgot the clutch once
- Chain wear? chain is good
- Derailleur alignment? check, it is straight and I actually took the wheel off and used the Park hangar alignment tool. Hangar is good and derailleur when mounted is straight
- Shifting is adjusted and smooth
- Mounted the Specialized chain guide before the last ride and chain still dropped/jammed in the chain guide

What I noticed after this weeks rides is what seems to be excessive, or abnormal wear on the Praxis ring. The entire outside, of the outside tooth is shiny. Not worn yet, but definitely heavy rubbing (see pics).

Any ideas or suggestions?

!View attachment 132580

Thanks!

It could be that one or all of the small bolts on the chainring are lose or tightened but one or all are out of torque spec. I put a new chain ring on a different bike . Along with new chain and rear mech. Tighten it all but could not get the chain to stay on thru all the gears . So I called a guy I know at the LBS . His first suggestion was even though I tightened the chainring down . It had to be torqued exactly to factory settings . I found out that spec and tried what the Mechanic had suggested . Sure enough that was the issue . I remember when he suggested this my first thought was how could that matter that much . They only go in so far I thought . But it was my issue . MAYBE IT's YOURS

 

[Marcela]

Not a Creo here but I've used Praxis 48t and 36t with a variety of chains and clutched and clutchless derailleur never had a chain drop on 9 and 11 spd.

Is the chainring aluminum or steel? If aluminum I'd suspect it may be wore and maybe wore if steel, or the chain may be wore.

 

[Cycle]

I'd replace the chain - it's noted GOOD - but if certain tests were done - it's more than likely stretched
to the point, that it no long fits the pitch of the sprockets, and more than likely will crawl off.
The easiest test is wrap the chain around the sprocket almost full circle tight as possible,
it should be impossible to pull any portion of the chain away from circle of sprocket.
If any portion of chain is floating offset from the teeth of sprocket. It's Junk.
Best point of test is 180 from free ends of chain.
Prolonged use like this will only destroy the sprockets as well.

Once the new chain is put to the same test, it will become quite clear.
One could lay them side by side, and see the pins of chain no long match a foot or two pulled tight.

Yes, that is actually a very good test. I originally checked with the Park tool, but did the "manual" test this morning as well and it is OK. I sent the photo of the chainring wear and the problem description to Praxis. They said that was "normal" wear, but did offer a discount to buy a new one from them
I think I will order the Garabunk ring and keep fiddling until it arrives.

Thanks for all the good tips. If I find out anything new I will post an update.

 

[Cycle]

It could be that one or all of the small bolts on the chainring are lose or tightened but one or all are out of torque spec. I put a new chain ring on a different bike . Along with new chain and rear mech. Tighten it all but could not get the chain to stay on thru all the gears . So I called a guy I know at the LBS . His first suggestion was even though I tightened the chainring down . It had to be torqued exactly to factory settings . I found out that spec and tried what the Mechanic had suggested . Sure enough that was the issue . I remember when he suggested this my first thought was how could that matter that much . They only go in so far I thought . But it was my issue . MAYBE IT's YOURS

Also good suggestion. I had the chainring off before the last rides to install the Specialized chain guide and torqued all the bolts to spec. Still fell off AND jammed in the chain guide. Though it did stop the chain from dropping into the bottom bracket and scraping the frame

 

[Cycle]

Does she have a habit of backpedaling? I had a chain drop recently doing that under the same conditions. It's probably due to the clutch in the chain ring motor system.

edited to add:

Usually I am going down hill at speed semi-coasting where the gearing has not caught up with the speed and I coast before starting to change gears.

That is interesting. Not sure what you are saying about "clutch in the chain ring motor". The Creo does not backpedal, under normal conditions. Are you saying you had an issue were it did backpedal?

 

[Zekeer]

That is interesting. Not sure what you are saying about "clutch in the chain ring motor". The Creo does not backpedal, under normal conditions. Are you saying you had an issue were it did backpedal?

Sorry should have read your post closer . Did you adjust the H and L limit screws ? Seriously sounds like what you need to do . If the chain is falling off you need to watch park tools derailleur adjustment . Which has nothing to do with a clutch . After reading your post slowly . I don't see where you did that . You said the shifting is fine . But that doesn't have anything to do with your derailleur . Don't mean to sound like a know it all but I worked on Bicycles Professionally for many years . Your limit screws control how far the chain moves in either direction . Here's a pretty good one Sounds like you have checked everything else .

 

[Cycle]

Sorry should have read your post closer . Did you adjust the H and L limit screws ? Seriously sounds like what you need to do . If the chain is falling off you need to watch park tools derailleur adjustment . Which has nothing to do with a clutch . After reading your post slowly . I don't see where you did that . You said the shifting is fine . But that doesn't have anything to do with your derailleur . Don't mean to sound like a know it all but I worked on Bicycles Professionally for many years . Your limit screws control how far the chain moves in either direction . Here's a pretty good one Sounds like you have checked everything else .

Zekeer,

The Park Tool vid's are great!! I should have been more clear about the drop, though. It is a chainring drop, in the front!! Not a cassette chain drop in the rear. That is the odd thing about the Creo, lot's of folks are having FRONT chainring drops. I have several MTB's and gravel bikes with 1x chainrings and have NEVER had a front chain drop. Creo's seem to do it frequently. Personally, I think that there is a design issue with the chain line and/or design issue with the Praxis ring. What is odd about my wifes bike is that it was not dropping the chainring (front), then it started too. So, was seeing if anyone else had the same experience.

 

[Zekeer]

Zekeer,

The Park Tool vid's are great!! I should have been more clear about the drop, though. It is a chainring drop, in the front!! Not a cassette chain drop in the rear. That is the odd thing about the Creo, lot's of folks are having FRONT chainring drops. I have several MTB's and gravel bikes with 1x chainrings and have NEVER had a front chain drop. Creo's seem to do it frequently. Personally, I think that there is a design issue with the chain line and/or design issue with the Praxis ring. What is odd about my wifes bike is that it was not dropping the chainring (front), then it started too. So, was seeing if anyone else had the same experience.

Aaah I see . Maybe as a last resort remove one link out of the chain . Just a thought Good luck to you

 

[Marcela]

It may be a combination of things when you are looking for one. I was going to post something a little bit ago and after review I'd say the outside tooth wear which holds the chain on through friction may be the culprit.

On my bikes, not Creo, I changed a rear derailleur and after some sloppy shifting did some investigation and noticed the mechanism springs between the two were quite a bit different. The original was pretty large, the replacement was half the size, which contributed to the sloppy shifting, still no chain drops though.

I'd say the outside tooth wear is one issue. Looking at the Creo specs uses a different derailleur than either Vado or Como, so maybe the spring has something to do also with tension on the chain which helps to keep it on the chainring.

 

[Zekeer]

It may be a combination of things when you are looking for one. I was going to post something a little bit ago and after review I'd say the outside tooth wear which holds the chain on through friction may be the culprit.

On my bikes, not Creo, I changed a rear derailleur and after some sloppy shifting did some investigation and noticed the mechanism springs between the two were quite a bit different. The original was pretty large, the replacement was half the size, which contributed to the sloppy shifting, still no chain drops though.

I'd say the outside tooth wear is one issue. Looking at the Creo specs uses a different derailleur than either Vado or Como, so maybe the spring has something to do also with tension on the chain which helps to keep it on the chainring.

A friend of mine owns a Trek Verve : His chain falls off on a regular basis . He weighs like 270 and he like most people think they know how to shift but don't. This is not meant as an insult. There are a lot of people that don't shift correctly , but always think they do . There's also a possibility that you have a link or 2 that is bent . Which can be the case now and then on brand new out of the box chains . When the link isn't seated exactly correct .
However , I would say that over the years . More then 1/2 of the Drive train Issues I encountered was USER Error . Often with experienced riders . I would guess a Creo is a sensitive bike . PS: I'm not saying the OP doesn't know how to shift . I'm simply pointing out that it's often the issue that nobody addresses . Because people get upset
One of the first things I remember in Courts Videos is his attention to mention not to pedal and e-bike while attempting to shift . It is amazing how many people I see riding e-bikes . That keep peddling thru the shift .

 

[Cycle]

A friend of mine owns a Trek Verve : His chain falls off on a regular basis . He weighs like 270 and he like most people think they know how to shift but don't. This is not meant as an insult. There are a lot of people that don't shift correctly , but always think they do . There's also a possibility that you have a link or 2 that is bent . Which can be the case now and then on brand new out of the box chains . When the link isn't seated exactly correct .
However , I would say that over the years . More then 1/2 of the Drive train Issues I encountered was USER Error . Often with experienced riders . I would guess a Creo is a sensitive bike . PS: I'm not saying the OP doesn't know how to shift . I'm simply pointing out that it's often the issue that nobody addresses . Because people get upset
One of the first things I remember in Courts Videos is his attention to mention not to pedal and e-bike while attempting to shift . It is amazing how many people I see riding e-bikes . That keep peddling thru the shift .

Interesting, and a point to consider. Do you have a link to the "Courts video", i'm not familiar with that reference.
A good idea about a possible bent link, that WOULD help explain that all of a sudden it was common occurrence. Perhaps, after the first drop it jammed and bent a link... from then on it would happen a bit easier. I'll check.

I have another friend who just got her bike out of the shop for chain drop issue and they blamed the worn Praxis. Replaced it with new. We'll see what happens to her.

 

[bobf]

Not to pedal is incorrect here. On a Creo it is necessary to pedal with reduced effort through a shift. It is a type 3 e-bike whose drive train stops when the rider does not pedal. I believe this is also true of your friend's Verve. Reduced effort is especially important when pedal force is boosted by a high level of assist.