How does a jockey wheel crack?

[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]

Originally Posted by Cicli

Simple math.

sHram = garbage.

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

[ColonelJLloyd]

Originally Posted by simonov

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]

Originally Posted by simonov

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]

Originally Posted by Cicli

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]

Originally Posted by simonov

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]

Originally Posted by Cicli

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]

Originally Posted by simonov

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]

Originally Posted by 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.

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]

Originally Posted by simonov

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]

Originally Posted by dddd

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]

Originally Posted by simonov

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]

Originally Posted by oldpotatoe

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]

Originally Posted by oldpotatoe

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]

Originally Posted by simonov

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.