How does a jockey wheel crack?

[FastVegan]

When cleaning up my bike I noticed a crack in the upper jockey wheel of a sram red rear mech. Cracked clean through from the
center straight out. I have seen this before and wonder how does it happen?
Any insight?
Thanks
Dave

[xjoex]

I believe this is a result of the stress related to the side load it receives when shifting.

-Joe

[oldpotatoe]

When cleaning up my bike I noticed a crack in the upper jockey wheel of a sram red rear mech. Cracked clean through from the
center straight out. I have seen this before and wonder how does it happen?
Any insight?
Thanks
Dave

Have yer LBS call sram and they will send a set of pulleys out freebie...

[forrestw]

Jockey wheels are injection molded plastic. If the process isn't designed correctly the parts may have residual stress. Also the bearings are press fit creating hoop stress which can result in the radial crack you saw.

[binxnyrwarrsoul]

It's SRAM, what can one expect? Just kiddin'. It's well documented I'm no fan-boy of SRAM, but, from one of my riding buddy's experience, their customer service is excellent.

[biker72]

The warranty guy where I work spends a LOT of time with SRAM stuff.

[foo_fighter]

Found this today....Is it a common SRAM problem?
The other issue is that the upper pulley uses a 4mm screw instead of a 5mm screw.:


https://lh3.googleusercontent.com/hvy2VzZkFKQozh4z4bpHPU0-166tgnsnXaXlE0rLl433EV5ehWXw6GKRETtemC6uAsnewbFKo6 oMsbTdeJfXOTJ3qxEFPGcgEivDJyi91Tr4wKQBM7ugV9UJckMA 6zZu4YiQjjmxKk8RmU8fmQMpyIl1DC0y76Nr3WRyXR1SPeYKZf 3qrQL72Ev6-qO297nKy3JzNDshQYhxqI4HtRXO6narOO3idCOZOxXquMlwJ5v qqDoxndIhe_fsbeKo2NWwSBDb-MUX2082QLz-1Lv4ZQ5eybb3_s__IFkGzkMXFj7sl4g8hZHjQX-bRtl3w2RdcbzgQ_m5_wnrhBdFeForMs7qUvdlkL3ZbXw-s-kl9eDwRn5U1nTJhzfqW5eT86f97l5PiNYyHaCkzOsIcvx6Lmh3 JzuHzX6ZwvWUSJo4AJ-8k28O1DwgiykOfg73RC_AUq0R6Xj0qvveMRcbK2jXG77OG8Pbp nbpUODZWUZ4737k14Ie3kC_3adpH3n0Ny-0WrSdt0dWn1dovQYqHT23NcUtjH76OxV0llic4jkJwdTQw2Uzp AJ0JQ_NxuZXKwmk6IP7IRi-lsHp1zpuA93xaQLjSHrCAhq8awAJ059okvyB27uJBUnXFfpwXD 1TLPQ4usgbzV_HlDvha0Y3854wEdhPDUo27CfWPAUe=w566-h755-no

[BobC]

Yes, had the same issue with SRAM pulleys. Went back to Campy. Now problem solved.

[bigbill]

I've been riding for 30 years and I've worn them smooth, but never seen one crack, the things you learn on the internet. Everything is Shimano or Campy.

[joosttx]

I've been riding for 30 years and I've worn them smooth, but never seen one crack, the things you learn on the internet. Everything is Shimano or Campy.

I cracked a shimano one this year. I think it was a result of a stick getting stuck in the deraileur and twisting it.

[oldpotatoe]

When cleaning up my bike I noticed a crack in the upper jockey wheel of a sram red rear mech. Cracked clean through from the
center straight out. I have seen this before and wonder how does it happen?
Any insight?
Thanks
Dave

First or early gen? Not uncommon on these pulleys...get a replacement or aftermarket replacement that will last longer.

Ahhhh from 2011..must be first/early gen. Yup, these DO have a rep for cracking..

[bigbill]

I cracked a shimano one this year. I think it was a result of a stick getting stuck in the deraileur and twisting it.

To be fair, I lost a Shimano pulley. My first 8 speed bike in 1991 had Dura Ace and about a week after I got it, a spoke nipple broke and the loose spoke split the RD and I only found one pulley. The one I found was fine.

[dcama5]

Recently, I installed a pair of KCNC alloy pulleys with internal bearings on a Shimano derailleur. These were used pulleys that I had been using for part of the season on a different derailleur. With the bike up in the work stand I started to turn the cranks and could not get the chain to run smoothly. It turned out, one of the KCNC pulleys got bent sideways at some time while on the other bike - lateral stress I guess.

[Cicli]

Simple math.

sHram = garbage. :bike:

[oldpotatoe]

Simple math.

sHram = garbage. :bike:

DOH!!!:rolleyes:

[tv_vt]

I've had Shimano jockey wheels crack, too. It's not just a SRAM thing. Fortunately it's not a 'ride over' type of malfunction. Probably not noticed until bike gets a very thorough cleaning.
New jockey wheels are a nice little pleasure, like new bar tape. Bike always seems to ride better.

[simonov]

Simple math.

sHram = garbage. :bike:

This is pretty tiresome. Bike parts from all brands break or have issues at some point in their evolution.

[ColonelJLloyd]

This is pretty tiresome. Bike parts from all brands break or have issues at some point in their evolution.

I have seen a couple cracked Shimano wheels. I've seen over a dozen from Campy NR RDs. Is this because there were so many and they were well used or because they suck?

It's an effin jockey wheel. Not a big outlay or complicated replacement procedure when one cracks no matter who the maker.

[Cicli]

This is pretty tiresome. Bike parts from all brands break or have issues at some point in their evolution.

I know, I just dont like sHram. Not even a little bit.

[simonov]

I know, I just dont like sHram. Not even a little bit.

That's pretty clear. Nor do you have to. But it isn't garbage. Actually, in my experience, it's been as, or more, reliable than Shimano or Campy.

[Cicli]

That's pretty clear. Nor do you have to. But it isn't garbage. Actually, in my experience, it's been as, or more, reliable than Shimano or Campy.

Yeah, I was involved in the hydraulic rim brake mess. They handled it very poorly. I never looked back to them for anything.

[simonov]

Yeah, I was involved in the hydraulic rim brake mess. They handled it very poorly. I never looked back to them for anything.

Total cluster. They really dropped the ball on that one. I can't recall a Campy screwup like that. I kinda think Shimano's levers that eat cables is almost as bad. I don't know if there was a major recall, but I know countless people who ended up stranded on rides with busted cables.

[bigbill]

I kinda think Shimano's levers that eat cables is almost as bad. I don't know if there was a major recall, but I know countless people who ended up stranded on rides with busted cables.

My garage is the "bike shop" here. I've got a pair of 3X readers in my toolbox just for picking the broken strands out of 9000 shifters. I've got 685 shifters on my gravel bike, they work great but I still plan on replacing the RD cable at least once a year.

[dddd]

Jockey wheels are injection molded plastic. If the process isn't designed correctly the parts may have residual stress. Also the bearings are press fit creating hoop stress which can result in the radial crack you saw.

I believe this is the case, and when extreme cold temperatures are added in, the tension seems to be what splits the plastic hoop.

Perhaps age-related shrinkage and weakening play their part as well, combined of course with the stresses of usage.

I note that I can't recall ever seeing a bushed Shimano pulley (or any Shimano pulley(!)) split in this fashion.

I find splits in the pulleys of some of the vintage bikes that I buy, and I continue to ride them! Only the Simplex brand plastic pulleys ever seem to suffer actual brittle failure of a serious sort, but I recall that Simplex made many derailers for certain of the "second-tier" Italian brands, such as Ofmega and Gipiemme.

[dddd]

Total cluster. They really dropped the ball on that one. I can't recall a Campy screwup like that. I kinda think Shimano's levers that eat cables is almost as bad. I don't know if there was a major recall, but I know countless people who ended up stranded on rides with busted cables.

I have been finding that frequent derailer cable failure is mostly the result of "cautiously tight" limit screw adjustments to the largest cog and chainring positions.

Though riders and mechanics are justifiably wary of the possibility of spoke contact or of the chain perhaps over-riding the large chainring, the limit screw must still allow some bit of derailer movement when the chain is on the largest cog or chainring, lest the cyclic tension in the cable caused by frame flex cause premature cable fatigue. And not to mention any ham-fisted shifts up to the largest sprockets!

And whenever wheels are changed, and the cable tension slightly adjusted, the limit screw should always be re-checked for some bit of "free" movement of the derailer when the largest cog or chainring has been selected.

Shimano has wisely incorporated solid last-shift travel stops into both STI levers on their latest higher-level gruppos, with their 8000 and 9100 front derailers no longer having any hi-limit screw at all (the HI screw is now a booster screw, not a limit screw).
But I suspect that the rear derailers may retain their lo-limit screws so as to prevent unwanted shifts toward the spokes resulting from frame flex and/or random tugging contact of external objects with the derailer cabling, which might pull the rear derailer into very bad territory behind the largest cog. So the rear derailer's Lo-limit screw stays for now.

I note that certain of Shimano's rear derailers of decades past had cable-saver arms that yielded to any extremes of cable tension via pre-loaded spring tension. Could such a feature re-appear, or will a few broken cables and perceived higher maintenance requirements simply be allowed to help with the sales of electronic shift systems?

[tctyres]

I have been finding that frequent derailer cable failure is mostly the result of "cautiously tight" limit screw adjustments to the largest cog and chainring positions.

Though riders and mechanics are justifiably wary of the possibility of spoke contact or of the chain perhaps over-riding the large chainring, the limit screw must still allow some bit of derailer movement when the chain is on the largest cog or chainring, lest the cyclic tension in the cable caused by frame flex cause premature cable fatigue. And not to mention any ham-fisted shifts up to the largest sprockets!

And whenever wheels are changed, and the cable tension slightly adjusted, the limit screw should always be re-checked for some bit of "free" movement of the derailer when the largest cog or chainring has been selected.

Shimano has wisely incorporated solid last-shift travel stops into both STI levers on their latest higher-level gruppos, with their 8000 and 9100 front derailers no longer having any hi-limit screw at all (the HI screw is now a booster screw, not a limit screw).
But I suspect that the rear derailers may retain their lo-limit screws so as to prevent unwanted shifts toward the spokes resulting from frame flex and/or random tugging contact of external objects with the derailer cabling, which might pull the rear derailer into very bad territory behind the largest cog. So the rear derailer's Lo-limit screw stays for now.

I note that certain of Shimano's rear derailers of decades past had cable-saver arms that yielded to any extremes of cable tension via pre-loaded spring tension. Could such a feature re-appear, or will a few broken cables and perceived higher maintenance requirements simply be allowed to help with the sales of electronic shift systems?

This is helpful. I've only had this failure once on a 11s Ultegra set-up, but I will check those limit stops now.

[oldpotatoe]

Total cluster. They really dropped the ball on that one. I can't recall a Campy screwup like that. I kinda think Shimano's levers that eat cables is almost as bad. I don't know if there was a major recall, but I know countless people who ended up stranded on rides with busted cables.

They didn't set any records when they had their red wifli rear der recall either..

A couple of calls to sram about exploding rear ders were 'interesting'...

[sales guy]

They didn't set any records when they had their red wifli rear der recall either..

A couple of calls to sram about exploding rear ders were 'interesting'...

The funnest thing was visiting the lab in Chicago and seeing 55 gallon trash drums overflowing with dead parts. And they would go thru 2 - 4 drums A MONTH!!! When they had the Reverb recall they had 8. I like the guys there, but many they have such problems and make such bad stuff.

I will say the Rival 1x is pretty nice. But other than that I steer people away from SRAM.

[simonov]

They didn't set any records when they had their red wifli rear der recall either..

A couple of calls to sram about exploding rear ders were 'interesting'...

Yeah...lots of companies have recalls. I actually give them credit where some companies never bother with a recall even though there are parts out there breaking. From my personal experience riding more than most and using groups from all three of the big companies, everything has been generally reliable and occasionally broken. I don't really have a dog in this fight other than I find blind SRAM bashing to run contrary to my 100K+ miles of experience on their parts over the last decade.

[oldpotatoe]

Yeah...lots of companies have recalls. I actually give them credit where some companies never bother with a recall even though there are parts out there breaking. From my personal experience riding more than most and using groups from all three of the big companies, everything has been generally reliable and occasionally broken. I don't really have a dog in this fight other than I find blind SRAM bashing to run contrary to my 100K+ miles of experience on their parts over the last decade.

Wow, lots of riding, good on ya! As a service oriented shop owner, I got to see the ‘goods and others’ of a lot of stuff. Our warranty frequency for sram(particularly early gen road stuff) was 4-5 times number 2, which was shimano STI levers, particularly 6500 and 6600...more than a few failures out of the box. Only a couple of Campagnolo(we were a Pro shop)...a rear wheel, a broken rear der carbon body (jra?)...a broken thumb button on a new, 2009 lever....just my experience.

PM me if you want to hear the story of ‘taco ed’ of sram...some/most here don’t want to hear it again.

[simonov]

Wow, lots of riding, good on ya! As a service oriented shop owner, I got to see the ‘goods and others’ of a lot of stuff. Our warranty frequency for sram(particularly early gen road stuff) was 4-5 times number 2, which was shimano STI levers, particularly 6500 and 6600...more than a few failures out of the box. Only a couple of Campagnolo(we were a Pro shop)...a rear wheel, a broken rear der carbon body (jra?)...a broken thumb button on a new, 2009 lever....just my experience.

PM me if you want to hear the story of ‘taco ed’ of sram...some/most here don’t want to hear it again.

Ha! I may take you up on that one day. I don't doubt they had some (many) issues in the early years. Maybe I've just gotten lucky, but I'm hard on my stuff and their gear has been fine. That said, the 11 speed stuff is much, much better than the 10 speed stuff. My campy groupset has been fine, but I've definitely been disappointed with their wheels, though. Again, that's just my experience. I'm sure that I'd feel differently if I had to deal with a disproportionate amount of warranty work as a shop owner. I have some experience with retail, though not bikes, and taking time (and money) to fix a company's issues sucks.

[topflightpro]

Not sure why it happens, but I've broken several pulleys on my Red RDs. I've replaced them in with some aluminum ones.

[foo_fighter]

Does anyone have any 5mm to 4mm reducer bushings?
If anyone has any spares let me know!

I tried google and mcmaster carr but couldn't find anything.

I had no idea the top pulley for SRAM is 4mm and the lower one 5mm. Both replacement pulleys I bought were for 5mm only.
I noticed some kits come with reducer bushings like:
https://images-na.ssl-images-amazon.com/images/I/61yhWn5GWiL._SL1001_.jpg
But my kit didn't.

[oldpotatoe]

Does anyone have any 5mm to 4mm reducer bushings?
If anyone has any spares let me know!

I tried google and mcmaster carr but couldn't find anything.

I had no idea the top pulley for SRAM is 4mm and the lower one 5mm. Both replacement pulleys I bought were for 5mm only.
I noticed some kits come with reducer bushings like:
https://images-na.ssl-images-amazon.com/images/I/61yhWn5GWiL._SL1001_.jpg
But my kit didn't.

Cuz a 4mm bolt is lighter than a 5mm bolt, of course.

[dddd]

Replacing pulleys with aftermarket can be complicated by bolt size and also by the new pulley's width where the plates clamp against the "hub" of the pulley.

I liked the ones you showed above, I was able to drill out the alloy "hub caps" for the 6mm bolts used on my Simplex rear derailer, but then had to shim/washer under the head of the bolts since the thicker, unthreaded shank of the now-too-long bolt bottomed against the threads in the inner cage plate.
Mine were found with just 10 teeth and no holes, but in the right color, and work just perfectly with the 9s chain I'm using on this old 10-speed (as in 5x2) Austrian relic.
Note the original semi-compact 52/36t chainrings on this late-1960's crankset, gets me through the foothills with just a 13-24t out back.

https://c1.staticflickr.com/9/8097/8386103582_4997241622_c.jpg

[bigbill]

In the late 80's, Shimano came out with a short cage XT derailleur. It shifted quickly but tended to snap. Myself and others ended up taking Shimano Light Action short cage derailleurs and installing Bullseye pulleys. They worked great. The pulleys on the XT RD weren't the problem, it was just a bad design, but the Light Action's were really good and I never broke one. It was still on my MTB in 1996 when I sold it to a friend's son.

The late 80's were fun times for MTB's in the PNW, we did all kinds of experiments with components. We made our own microdrives with touring cranks before the industry did. Felt sorry for Suntour not surviving shimano.

[dddd]

I got to thinking, if the OP's pulley needs a reducing sleeve just to keep the pulley centered on the bolt, then some plastic tubing of approximate dimensions should be an easy thing to come up with. And even if the diameter is a bit too small or large, one could slit the sleeve lengthwise and spread it (or trim some from one edge) as needed.
Alternately, you could perhaps roll a sleeve with one or two wraps of the sort of thick foil used on wine bottles, or something similar(?).

[dddd]

In the late 80's, Shimano came out with a short cage XT derailleur. It shifted quickly but tended to snap. Myself and others ended up taking Shimano Light Action short cage derailleurs and installing Bullseye pulleys. They worked great. The pulleys on the XT RD weren't the problem, it was just a bad design, but the Light Action's were really good and I never broke one. It was still on my MTB in 1996 when I sold it to a friend's son.

The late 80's were fun times for MTB's in the PNW, we did all kinds of experiments with components. We made our own microdrives with touring cranks before the industry did. Felt sorry for Suntour not surviving shimano.

I sure had good luck with all of the Shimano gear from the late 1980's, as soon as the 7s chain and Hyperglide became available.
I'm still using a short-cage XT from the 7s era on my Huffy 27.5-"plus" bike, it really helped to control the chain slap I was getting with the original long-cage Shimano Altus rear derailer.
https://c2.staticflickr.com/6/5622/30977693802_dd5a7b8c0b_c.jpg

[bikinchris]

This is pretty tiresome. Bike parts from all brands break or have issues at some point in their evolution.

Over time, I have had my respect for some posters drop a lot. Ignoring the multitude of design flaws from every company except SRAM is crap.

I was the warranty guy at our shop and a had a bin for each company. They were all very full. Always.

Ignoring design flaws is not uncommon. For instance:

Shimano intentionally designed their 7 and 8 speed rear derailleurs (Light Action) with a spring so light that SRAM grip shift wouldn't shift well. It was so light that it didn't shift with their own shifters either after a while. I installed hundreds of the surgical tubing helpers to keep customers happy.

Campy index springs were often broken on new bikes, leading to poor shifting. I have also changed hundreds of those on bikes still under warranty and Campy would not make them good.

Neither company would admit they had a problem.

ALL companies have had problems. None are immune.

[foo_fighter]

Yeah, that's exactly what I did as a temporary fix....but it's hard to find metric sized tubing. After slitting it, I had to add a layer of tape to get it to be snug.

I got to thinking, if the OP's pulley needs a reducing sleeve just to keep the pulley centered on the bolt, then some plastic tubing of approximate dimensions should be an easy thing to come up with. And even if the diameter is a bit too small or large, one could slit the sleeve lengthwise and spread it (or trim some from one edge) as needed.
Alternately, you could perhaps roll a sleeve with one or two wraps of the sort of thick foil used on wine bottles, or something similar(?).

[dave thompson]

Does anyone have any 5mm to 4mm reducer bushings?
If anyone has any spares let me know!

I tried google and mcmaster carr but couldn't find anything.

I had no idea the top pulley for SRAM is 4mm and the lower one 5mm. Both replacement pulleys I bought were for 5mm only.
I noticed some kits come with reducer bushings like:
https://images-na.ssl-images-amazon.com/images/I/61yhWn5GWiL._SL1001_.jpg
But my kit didn't.
Tacx pulleys come with a variety of bushings so they can be used with Shimano, Campy and SRAM. You might put out a request for these bushings as I’m sure that someone has what you need just laying around. I do have some but I’m 3,000 miles away for the next 6 months.

I just looked up the Tacx pulleys https://tacx.com/products/jockey-wheels/ You might contact their support folks.