Spoke protector?

[oneten]

My chain recently derailled into the spokes while changing gear on an upward slope which meant I pulled it tight to the hub.(reminder to self...you shouldn't change gear under load ). I had a real struggle to free the chain and was naturally puzzled as to what had caused it as thought everything had been set up correctly and it had never happened before.
After carefully riding for a few days more, after adjusting the 'L' limit screw, I heard the tell tale 'ping' of a spoke snapping and the wheel went way out of true.
Thinking this would just need a single spoke replacement, I removed the freewheel only to find I had a broken axle snapped clean in half, plus all the outer spokes on the drive train side badly abraded. I replaced all 9 of them in the end the LBS supplied me with the spokes, plus a new axle and cone set.
I reckon the broken axle had caused the gear adjustment to go out of kilter resulting in the chain being thrown into the spokes.
Anyone else had this experience? In view of the potential for damage to the spokes, I'm wondering if one of those plastic disc protector?'s might be an idea?

[gaz]

Achieved about four years ago by overshifting the chain. My own fault for not checking the limit screws on a bike I'd bought second hand.

I still don't use spoke protectors.

[531colin]

I suspect Gaz's spoke flange was cracked already.....fatigue or stress/corrosion cracking.
The big hub manufacturers are careful what alloy they use, and the flanges are forged........ for example, flange failure on Shimano hubs is almost unheard of, and they are numerically the most common hubs by a mile.
Spoke protection discs were OK in the days when there was room for them, for example behind a 5 speed block.....these days there often isn't room between a 9 speed cassette and the spokes. You do see discs with a big hole in the middle.....there can be enough clearance for them, but they don't protect the spokes right down by the hub, which is where the chain gouges them.......

[Brucey]

I suspect Gaz's spoke flange was cracked already.....fatigue or stress/corrosion cracking....

yup, I reckon the chain jam just administered a 'coup de grace' perhaps by virtue of the increased side loads as much as anything else.

In point of fact I have never seen a flange fracture in an aluminium hub that wasn't associated with prior damage of some kind. This is normally easily spotted, because the fracture faces will be bright where they are fresh, and dull grey where they are old and corroded.

In simple overload, the spokes usually break before the flange fails; an exception to this might be a current rear SA aluminium hub (very soft); with a 13G spoke in it, it might pull through the flange, even a 14G spoke causes the hole to go oval before the spoke breaks if it is pulled hard enough.

Spoke protectors are rightly named. If you really need one, there is something else wrong, and you should look to your maintenance; it could be that the brakes are in a similar (bad) state.

BTW if you do gouge a few spokes, simply dressing the gouges with a swiss file will usually make the spokes good enough to outlast the rim. If they are worse than that or have to last longer, you normally need only replace 9 rather than the whole lot. If in the wilds without enough spare spokes, the gouged ones can usually be put on the NDS where they are less likely to break and can be replaced later when convenient.

cheers

[oneten]

Achieved about four years ago by overshifting the chain. My own fault for not checking the limit screws on a bike I'd bought second hand.

OUCH!! Thankfully no damage to my hub at all bar a couple of minor scratches.

“

Spoke protectors are rightly named. If you really need one, there is something else wrong, and you should look to your maintenance; it could be that the brakes are in a similar (bad) state.

BTW if you do gouge a few spokes, simply dressing the gouges with a swiss file will usually make the spokes good enough to outlast the rim. If they are worse than that or have to last longer, you normally need only replace 9 rather than the whole lot. If in the wilds without enough spare spokes, the gouged ones can usually be put on the NDS where they are less likely to break and can be replaced later when convenient.

cheers

Thanks - Having done the axle and checked the low limit screw, everything's running nicely now and now don't see the need for a plastic protector disc after all.(plus couldn't be bothered to remove freewheel again )
I like the tip about dressing the scraped section of the spokes but they were badly gouged and I have piece of mind. Actually, a second one snapped while I was loosening it.

[NATURAL ANKLING]

Hi,
All my bikes have naff plastic spoke protectors (if you want to call them that).

I have had one rear derailleur, off road wrap around the wheel, but I had my trusty naff protector fitted so spokes were fine.

Have numerous rear wheels with gouged spokes from skip bikes................none had a Frisbee fitted.
Maybe they were removed to unjam chain

Make of that what you want, none are above eight speed.
Will we ever see a TDF bike with one fitted

Who is the perfect mechanic anyway who never has a problem

[keyboardmonkey]

My 9spd bike came with such a thing - aka a "dork disc" - and 11-25 cassette. I didn't put it back on when I swapped the cassette for a 13-34 one.

[gregoryoftours]

They are a bit naff, but occasionally your derailleur can get knocked/pushed further than the L limit screw would normally allow, and in that eventuality they can be helpful. More often than not they are noisy floppers or rub noisily against the back of the freewheel/cassette so I tend to take them off. I'd be most likely to leave them on a cheap bike where the rear mech has flexy tin foil jockey cage and floppy loose pivots from the get go, especially where someone inexperienced is going to use the bike and do all sorts of unkind shifting. Any more names for the spoke saucer? dork disc is one I haven't heard before, we call them 'bobby discs'!

[NATURAL ANKLING]

Hi,
Naff bike
Naff bits
Naff rider
Naff maintenance
That's me

[tim-b]

Hi
The last one that I removed only needed a pair of scissors, the wheel, the cassette and everything else stayed in situ
Regards
tim-b

[pete75]

My 9spd bike came with such a thing - aka a "dork disc" - and 11-25 cassette. I didn't put it back on when I swapped the cassette for a 13-34 one.

From the Urban Dictionary " A dork is also someone who can be themselves and not care what anyone thinks." So if you want one fit it and to hell with what anyone else says.

[PT1029]

I have never been a fan of spoke protectors (mostly aesthetics plus the aluminium one of my youth always rubbed on the gear in 1st gear - not through poor adjustment, but because the protector always got buckled).
I now look a bit better at them. If you have a new 6 or 7 speed screw on Shimano freewheel, the lower sprockets are mounted on carrier arms (like the top end cassettes, but less refined). Should you get your chain off into the spokes, it gets caught in the hollow space under the lower sprockets, from where it is usually impossible to pull/fiddle the chain out. Usually the only way to get the chain out is to drop the wheel out of the drops outs (can't fully remove as its attached by the jammed chain....), put a block remover on and use a big spanner to unscrew the freewheel, whilst trying to ignore the sounds of the chain being forced over the increasingly marked spokes.