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Planet X XLS mech hanger - warning

tgotbtgotb Posts: 4,714
edited September 2017 in Cyclocross
I've had a few mech hanger failures on my XLSs over the last couple of seasons. Until now I'd written them off as unavoidable wear and tear (the bikes get a pretty hard life, and the hanger is supposed to act as a fuse), but recent findings suggest that the stock mech hangers, at least as suppied on older frames, may not be up to the job.

The first sign of trouble is normally slightly dodgy shifting, generally in muddy conditions. This gets progressively worse over the course of a race, or multiple races, with shifts onto the largest sprockets feeling a bit "wierd". Once it gets to this stage, it's only a matter of time before a shift to the lowest gear sends the mech into the rear wheel, and it's time to start running.

I finally got the missing piece of the jigsaw after the Bigfoot CC race at Cyclopark a couple of weeks ago. Both bikes had been very thoroughly fettled over Xmas, and apart from a dodgy tub were both in tip top condition. I was originally planning to leave one in the pits, and change mid-race if required, but a clubmate broke his mech before the start, so I gave him the pit bike.

About half way through the race, I started to get the dodgy shifting, which I assumed at the time was just grass in the mech. Knowing there was no spare I nursed the bike around the course, minimising shifts, avoiding the lowest gear entirely, and riding the final lap with no shifts at all. Both my clubmate and I finished the race; he hadn't had any issues with the shifting.

On cleaning the bikes, I discovered a crack in the hanger of the bike I'd been riding, at the rear-most screw hole:
KybzIfFh.jpg
This is the point at which every hanger has failed in the past; this hanger was brand new before the race. The hanger had deformed enough to stop the rear wheel dropping out when the QR was released. The pit bike ridden by my clubmate was in better shape, but the hanger was already showing plastic deformation in the same place, and the threaded hole had elongated.

There's clearly not a lot of material here; this is probably the most highly stressed part of the hanger, and the high chain tension in my single-ring setup is probably exacerbating the situation. Interestingly, I saw an XLS advertised on the web (not this site) very recently, with a crack in the same place. I PMed the seller to point it out, but haven't received a reply.

The hanger appears to be made from cast aluminium. It looks like Planet X have now switched to machined hangers from Wheels Mfg. These should be a bit stronger, which may solve the problem; I have some on order, and will report back in due course. If that doesn't work, I'll either look at whether it's possible to get some made with a bit of additional material at the stress point, or just get some made from stainless steel.

In the meantime, check your mech hangers! If yours is cracked, it'll be clearly visible; if it's starting to go but not yet cracked, the elongated hole (and necking of the material behind the hole) should be visible if you remove the wheel and the rear-most screw attaching the hanger to the frame.

I'd be interested to know how common this problem is; when you've had a chance to check your bike, please post here and let us know. Since I suspect chain tension is a contributory factor, it might also be worth mentioning whether or not you have a single ring setup.
Pannier, 120rpm.

Posts

  • VamPVamP Posts: 674
    Slightly OT but I can echo the single ring contributory factor. Since switching to single ring I have broken 8, that's EIGHT hangers, compared to about 4 or 5 in the whole time I was running a double.

    Part of that is the poor design of the Csix2 hanger, which has even less material at it's weakest point than the SLX one, but I have now had replacements machined from aluminium, which skip that screw hole altogether and which are much much stronger, and I have broken two of those already. Both times a small bit of gravel jammed in the rear mech.

    There's a moral in here somewhere, and part of it is that when it's going to go, it's going to go! But it has also made me think about the single ring set-up, and possibly opting for a slacker system in the future, at the expense of perhaps the occasional chain drop.

    A team mate uses SRAM X1 mechs and has not broken any in two seasons, since making the switch. He works in the industry, and has not heard of another X1 going either - cue a deluge of X1 users reporting breakages - but it does appear to be a more robust design, so unless Shimano bring out their own version this year, I'll probably move to X1 for next season.
  • tgotbtgotb Posts: 4,714
    I've been using SRAM X9 mechs for the last 2 seasons. The only failure I've had was caused by a crash which sent the mech into the back wheel; I'm pretty sure it was in one piece when it entered the wheel. The crash itself was the result of a total brake failure (at Welwyn last year) caused by trying to squeeze a bit of extra life out of two £5 pairs of brake pads. There's a lesson there!

    I've already lengthened my chains once, with no issues, will probably lengthen them again over the Summer.
    Pannier, 120rpm.
  • VamPVamP Posts: 674
    Interesting. I was keeping a tally at the Rockingham rear mech graveyard and of the 30 odd mechs that went there, the vast majority were Shimano. I guess road cages and jockey wheels are not designed with the thought of avoiding debris accumulation in mind.

    Is the X9 a clutch mech? Works fine with road shifter? Any downsides as opposed to the CX1 that you are aware of?
  • tgotbtgotb Posts: 4,714
    Interesting. I was keeping a tally at the Rockingham rear mech graveyard and of the 30 odd mechs that went there, the vast majority were Shimano. I guess road cages and jockey wheels are not designed with the thought of avoiding debris accumulation in mind.

    Is the X9 a clutch mech? Works fine with road shifter? Any downsides as opposed to the CX1 that you are aware of?
    Yes, it's a clutch mech, and works fine with the SRAM road shifters (all 10 speed). I haven't researched/compared with the CX1 mech.
    Downsides I've encountered:
    - High chain tension makes it a bit harder to shift to the largest sprockets (though presumably a feature of the overall system rather than the specific mech)
    - Ball bearing jockey wheels need quite a lot of TLC, including removing the bearing seals, cleaning and re-greasing after every muddy race
    - Very reluctant to go into the smallest sprocket. Not really an issue for me, and I should imagine this is more to do with the chainline than anything else (my chainrings are on the inner position, and not dished like the CX1s).

    You're welcome to have a play after the race on Sunday, assuming I haven't snapped both hangers by that stage :-)
    Pannier, 120rpm.
  • VamPVamP Posts: 674
    Are you doing the double this weekend?

    Sunday should be a laugh, bouncing around in the frozen ruts we will have created on Saturday :D
  • tgotbtgotb Posts: 4,714
    Are you doing the double this weekend?

    Sunday should be a laugh, bouncing around in the frozen ruts we will have created on Saturday :D
    Just the Sunday I'm afraid - will be there first thing on Saturday with Junior, but not for the afternoon's rut creation...
    Pannier, 120rpm.
  • devhadsdevhads Posts: 236
    - Very reluctant to go into the smallest sprocket.

    I thought this was just me but mine also reluctantly goes in to the smallest sprocket.
    Not really an issue for me

    Me neither, the only time I've needed it was at Fakenham, downhill road section with a tailwind. I had to bump the back wheel to get it to shift and was still spinning out on a 36-11
  • Are you doing the double this weekend?

    Sunday should be a laugh, bouncing around in the frozen ruts we will have created on Saturday :D
    Just the Sunday I'm afraid - will be there first thing on Saturday with Junior, but not for the afternoon's rut creation...
    You leaving us plebs to it on Saturday then? ;)
  • R8JimBob88R8JimBob88 Posts: 285
    Resurrecting an old thread :D

    Same issue here with my wife's new XLS. Less than a month old and the shifting was poor across the middle of the cassette. Lots of tinkering and adjusting (ample amount of swearing too) and I eventually spotted that the mech hanger had cracked and the bolt hole is slightly elongated.

    I've emailed Planet X
    If you do what you have always done, you will get what you always got....
  • tgotbtgotb Posts: 4,714
    I switched to hangers without that hole last season (I found a WheelsMfg equivalent). Didn't do enough racing for it to be a proper test, but no issues so far...
    Pannier, 120rpm.
  • jds_1981jds_1981 Posts: 1,858
    TGOTB wrote:
    I switched to hangers without that hole last season (I found a WheelsMfg equivalent). Didn't do enough racing for it to be a proper test, but no issues so far...

    Ooh, do you have a link to the correct type? Having just got through my last of three spare hangers I'd like other options. That and the fact that the XLS hangers are currently £20. The Wheels Mfg hangers didn't look cheaper but if more resilient....

    Edit: never mind, it's type DROPOUT 248, while the planet x style is DROPOUT 246
    FCN 9 || FCN 5
  • Just had exactly the same thing happen to me, half a lap into the first CX race of the year and my hanger failed throwing the mech into the wheel and busting a spoke.

    I'll have a look at those Wheels Mfg hangers.
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