[Closed] Smashing rear mechs

I've only ever seen it done once on some wetwoodwork, rear tyre slipped off, bang goes the rear mech.

Two lots of mech damage I think were due to a link failing on the chain and then being pulled through the mech while pedalling hard. It jams and bends the mech and hanger. The last one was due to a fallen branch catching on it - I'm surprised I stayed on the bike.

I broke two XO rear mechs within 6 months. Branch/stick goes into back wheel, wheel rotates taking the rear mech with it.

I suppose it's all about where you ride and what's on the ground. We ride one particular wood where it has happened several times within the group because there are so many loose branches on the ground.

I'm just interested as a lot of people give fragility of a mech as a reason to go gear hub. I run both, so far trouble free.

I smashed a mech last Sunday, bashing down a a rocky decent in swaledale, it didn't come off but I had to bend it out of the Spokes. You can see where something hit it very hard. I was more annoyed about the wheel as it had just been re trued and spoked.

I was busy crashing into a tree but what I think happened; Fast steep rh corner and the bike went over on its side and the rolled a bit. I came off and got it back together for the next section without thinking to check the bike. I kinda go with the get up and get on with it mentality! Anyway into the next section and click clack bollox! Chain had sort of wrapped itself round the bottom of the mech and then the whole lot was pulled into the wheel wrecking 6 spokes. Damn. New rear mech,new chain,6 spokes and a true reqd! Mech was 2 weeks old. Had an x9 snap on a 2 week old Pinnacle from Evans as well. No reason - it just snapped. They were dicks about it as well so I wont ever use them again.

I was at a CX race the other week where there were about 23 broken mechs/hangers. It was v. muddy but there were some bits with stones and we reckoned the stones were getting dragged into the mechs like the chain link above ^^
Interestingly, the winner and first 3 were on SRAM I think so mostly Shimano/Campag that broke. (NB. I didn't actually do a proper survey on this - just what folks were saying)

Don't say that! I did once and did two mechs in the next few months.

One I amfairly sure was a stick - the other probably was

I'm a serial rear mech smasher. I'd never go up to more than XT/X9 because I'd feel as soon as I put it on that its days would be numbered.

I don't tend to terminate them when hooning down something rocky and GGGNNAAAAAAAAARRR. The total opposite in fact.

My last one was an XT mech which I sheared clean in half - no slightly bent cages or owt - it then launched itself into the back wheel taking out half the spokes. I managed to do that while slowly pootling through a completely flat orchard, and clipped a tree stump

I was destructive as a child though

Yep, you're now doomed. Until it happens you wonder what the fuss is about, but I managed it JRA (slowly) for the first time a few weeks ago

It was dark so no idea what caused it, but it totalled the hanger, mech and cracked the outer cable.

I've trashed loads. Quite often as a chain related incident - chian catching on tyre, chain catching on mech cage over bumpy ground, that kinda thing.

However a love of techy rocky singletrack also has accounted for a fair few - I usually expect to damage at least one a year in Les Arcs - lots of "wiggle the bike through the tiny gap in the rocks" stuff - QRs, discs, pedals, cranks, bash rings and mechs all get a beasting.

I have several beautiful mechs, all in perfect condition.

Lovely pieces of precision engineering, nice to handle and look at. So nice that it would be a shame to drag them through all the mud and guck, bash against rocks, or get dragged off in heather. Who would be so heartless to do that to them?

So they live on a shelf in my shed.

😆

i've broken an XTR mech after 3 years usage - the stopper broke and the spring contracted, but i think that was years of abuse like taking the hardtail down the Mojo at Cwm Carn - mazing feeling overtaking Downhillers on a hardtail! - ha ha ha

then bent an XT mech when a stick got dragged into the wheel then pulled the rear mech with it - wasn't going particullay fast and only bent the rear hanger so bent it back and the mech is working fine on my comuter - new XTR is on my FS for year and half no troubles.....yet

Done a few it tends to be sticks getting pulled in, Done a few mech hangers which I assume were rock hits!

Bent the hanger twice on steel frames, once racing at Eastway in the late 90's, 2nd time a few months ago when a stick got caught, both times the RD survived. the only loss was on the road with a 7800 Dura Ace, with KCNC jockey wheels, one of these decided to break, snapping the RD in half, and bending the Ti frame hanger.

did an X0 mech on the road to the trails - no idea how or the cause
Split the bottom [jockey wheells and springy bit] from the top [ metal bit that moves in and out] , bent the botom cage out at a 90 degree angle and split one of the jockey wheels in half removed it all from the top half and nevr found the spring.
Rebuild it and it has been fine for the last 3 years.

Snapped a carbon X0 one on the high street but they were crap - the bottom jockey wheel cage sheered off - iirc the chain used to wear through the "carbon" bit

the bottom jockey wheel cage sheered off - iirc the chain used to wear through the "carbon" bit

Yeah, I just noticed that happening on mine. Anything I can do about it, or do I just wait for the thing to explode?

I killed two mech hangers this summer, first one when I had a double flat and dismounted sideways on some nice slidey slate, second one when a big old rock bounced up and walloped the mech. The mech in question is still working fine though.

I've asked the same question as the OP quite a few times, been riding for about 15 years now and hadn't ever done a mech until this year. I think I naturally make sure if it's a tight gap I er on the side of smashing the other side of the frame rather than the mech and am generally more cautious of that side of the bike.

The one I did break was at Fort William, only damage was a snapped return spring, the internal pivot spring, not the one you can see. No idea how it happened as there was no noise, or feeling through the pedals, just went out of gear and the chain went slack. Wonder if the spring just snapped rather than it getting caught on anytihng. Was quite odd, but 1 in 15 years is ok.

Totally destroyed a lovely 7spd Ultegra rear mech in the early '90s whilst doing a river crossing in the Menteiths. My language was particularly unpleasant for the reaminder of the day due to the shortened chain riding up onto a larger sprocket and locking up. The final straw came when the poor abused chain snapped in two.
I never realised how high I could throw a chain vertically until that day..... 😯

mint imperial you can get spare outers from ebay iirc but not the bit that attaches to the top of the mech - perhaps try gluing something where it is wearing as sort of scuff plate?

perhaps try gluing something where it is wearing as sort of scuff plate?

Worth a try, cheers. Time to crack open the Araldite then...

I've broken loads of mechs/hangers in my time but nowhere near as many in the last few years (coinsiding with no longer racing DH)

smashing mechs off rocks etc is almost always due to poor judgement/visual spacial skills, same goes for hitting bars off trees.

mechs/hangers can also get bent through very hard riding without actually hitting anything other than themselves or the bikes chainstays then can catch a spoke and self destruct. had this happen more than a few times, bottoming out harshly on the compression hit half way down the Ft William off beat wall for example.

they are also prone to bending in crashes/bails, my DH bike almost always has a bent mech on it from this. (if it's bent I'll check spoke clearance but no point repacing it as I only run a 7spd cassette (nice gap between top sprocket and spokes/hub flange) and only use the 4 or 5 smallest sprockets anyway so even bent mechs still index fine

first mech I've ripped clean off a bike in years was just a few weeks ago and entirely my own fault, riding a fast section of singltrack on a group nightride, a twig/stick got chucked up into the chain/mech/stays but I was leading out the group and didn't want to get caught so didn't pull over to remove it, rode on for another minute before it eventually broke/fell out of it's own accord, it had clearly bent the hanger (give away was gears were no longer indexed) but I CBA making a fuss so just rode on thinking I'll sort it out after the ride's finished but after a few more miles when we reached a short steep climb I shifted into the top sprocket and the mech instantly caught a spoke and jammed (I stopped quicky enough that nothing snapped, pushed up the hill, changed back into the middle of the cassette and continued on. 5 mins later I needed to change down to hop up some steps onto a bridge and did so without thinking.. oops!! pressed the shifter and imediately the mech caught a spoke again bringing me to a halt but this time as I was accelerating the force snapped the hanger.
on inspecting the mech (next day, it had luckily not bent) so just a £6 hanger to replace 😉

Ive seen one smashed by a mate of mine, large drop, large bloke, FSR frame, chain too short. brand new one ride old x7 mech ripped to pieces by the chain growth.

Unfortunately he was on my bike!

I've done an X7 and my mate did an X0 whilst riding (twig into mech). Also bent out of shape an XT shadow somehow, it was quite subtle so took a while to spot why the shifting was out.