Rear Hub Broken, Seeking New

[tkatzir]

After a little over 30,000 km this (no need to click, image below) happened.
Hub is Shimano Ultegra 32 holes.

Seeking recommendation for a new rear wheel.
I use it for road-only (no gravel, no "Italian White Roads".)
Mostly audax, but sometimes club rides, and (peaking above 700 watts) HIIT's.

The rim was Mavic Open-Pro.

Should I stick with 32 spokes?
Would 28 spokes mean more "meat" in the flanges? Would I be better with a wheel with 28 thick spokes?

Any help will be appreciated.

[Brucey]

can you manage a close-up of the fracture area?

cheers

[drossall]

I've had that happen with a couple of hubs. I'd have thought fewer spokes would mean more load on each spoke. Can't see that would help. I'd have gone for 36 instead on that argument, but 32 should be good for most usage, except if very heavily laden.

[tkatzir]

can you manage a close-up of the fracture area?

cheers

Higher res images below.

32 should be good for most usage, except if very heavily laden.

I weight less than 85 kg.
I guess 30,000 km is good value for money in this day and age...

[Brucey]

shimano hubs have pretty good forged hubshells. They very occasionally make one that is a poor design but that doesn't appear to be one such.

Some things that cause hubshells to break include

a) poor material choice (does not affect shimano usually)
b)  poor fit of spokes
c)  hub dry (no oil spray)
d)  hub sprayed with salty water (winter use) causing corrosion
e)  anodised hubshell (anodising cracks and creates focus for corrosion)
f)  poor finish on underside of spoke head (often there are two flash lines from the spoke head forging die that create stress raisers)
g) some kind of gross spoke overload during service
h) excessive spoke tension in build
i) excessive fatigue loadings

The wheel appears to have been built (or repaired) using a mixture of DT spokes and Sacchetti (ACI) spokes.  Not sure if that is related to the failure or not.

If I had to guess I'd suggest that the greater discolouration on the fracture surface near the trailing (pulling) spoke means that the crack started there first, and that the hub was dry enough that winter road salt may have helped the (fatigue) crack along at some speed; many materials are effectively ~1/3 the strength when there is salty water present.

If there is a systematic failure going on, you might see cracks in other places on the flange, if you examine using a magnifying glass.

FWIW I usually treat hubs that are to see winter use with waxoyl around the spoke holes, or make sure that the hub has overspill of chain lube (or hub lube)  during the very worst weather when there is liable to be plenty of road salt about the place. This falls into the 'wont do any harm, might do some good' category.

I don't think going to a 28h built would help in the slightest. Going to a 36h build would reduce the cyclic (fatigue) loadings in the spokes somewhat, for any given wheel usage. Probably this effect is more significant than the slight increase in stress concentration around the spoke holes in the flange caused by them being closer together.

After 30000 km, the wheel has gone round over 1500000 times.  Seems like quite a lot to me.

cheers

[interested]

After a little over 30,000 km this (no need to click, image below) happened.
Hub is Shimano Ultegra 32 holes.

I recently lost a Shimano Ultegra FH-6600 hub in a similar way. I suspect that road salt played an important role in its demise. Photos here: 
https://www.flickr.com/photos/28712360@N08/albums/72157694677663645

 
Seeking recommendation for a new rear wheel.
I use it for road-only (no gravel, no "Italian White Roads".)
Mostly audax, but sometimes club rides, and (peaking above 700 watts) HIIT's.

 
 
I bought a pair of Shimano FH-5800 hubs. Not sure they are better, and I haven't built the wheels yet so this isn't a recommendation, but I have generally been pleased with the Shimano 105 series in the past. 

 
Should I stick with 32 spokes?
Would 28 spokes mean more "meat" in the flanges? Would I be better with a wheel with 28 thick spokes?

Not sure fewer spoke holes would help much. In my case and others I have seen, distance between spoke holes doesn't seem to be an issue. If so, one would have expected the flange would have been teared off where the distance between spoke holes was smallest, but from what I have seen, the cracks seem to start at the top of two spoke holes and tearing apart the flange from below the spoke holes, just like on your hub. 
 
In any case, fewer spoke holes means that each spoke will have a higher spoke tension, and spoke tension seems to be part of the problem, since it is always on the drive side the flange seems to snap. 
 
AFAIK, hub flange breakage is reasonable rare and seems to happen to even reputable manufacturers, so there doesn't seem be any real pattern that mere mortals can discern. The best advice probably is to buy the hub you like the most within the budget, with factors like servicing (cup-and-cone vs cartridge bearings) being more important than trying to avoid another flange breaking. 

[LittleWheelsandBig]

It might be worth noting that Tal lives in a seaside town in a Mediterranean country, not in the UK.

I'd agree with the rare random event explanation, rather than systematic weakness.

[drossall]

+1. I've recently built some wheels on some NOS 6600 hubs, and I'm a heavier rider. This thread is not causing me any concern at all.

[Brucey]

....In any case, fewer spoke holes means that each spoke will have a higher spoke tension....

The spoke tension used ought to be limited by the rim manufacturer's recommendation in most cases. Thus wheels with fewer spokes don't have higher spoke tensions unless the builder has done something wrong.

 However wheels with fewer spokes are necessarily more flexible and in addition the spokes see higher cyclic (i.e. fatigue) loading.

 Sensible variations in the  spoke tension used to build the wheels don't greatly affect either the wheel stiffness (in normal wheel loading) or the cyclic stresses seen in the spokes.  However depending on the model used for the fatigue damage caused, higher means stresses (eg due to higher spoke tension) do affect the amount of cumulative fatigue damage.

It might be worth noting that Tal lives in a seaside town in a Mediterranean country, not in the UK....

In which case there may be sea salt in the environment anyway.  I have seen instances where a single droplet of salty water landing on a bike has subsequently caused severe corrosion damage; what happens is that as the droplet dries out, the salt solution becomes a very strong (saturated) solution with plenty of available oxygen; this causes severe and rapid corrosion.  Because the anodising is always breached where the elbow bears against the hub flange, you have the 'large cathode, small anode' corrosion situation which can cause cracks to form and propagate where they wouldn't otherwise.

I'd suggest it would be prudent to apply corrosion protection (as previously described) in future.

cheers
 

[Polar Bear]

Personally I think 30,000 kms is a reasonable if not stellar return.  I'd be irritated but not deterred as flanges do occasionally, very occasionally, fail.   If, other than this failure the hub has been a reliable servant, then I'd probably replace like with like.

[tkatzir]

Personally I think 30,000 kms is a reasonable if not stellar return.  I'd be irritated but not deterred as flanges do occasionally, very occasionally, fail.   If, other than this failure the hub has been a reliable servant, then I'd probably replace like with like.

Shimano replied my tweet, and I'm working with the local distributor.
Hope I'll have good news soon.

If I won't be able to get it replaced - I'll probably buy a new Ultegra, or ask for recommendations as in the original post.

Stay tuned...

[D.A.L.E.]

https://yacf.co.uk/forum/index.php?topic=105622.msg2223564#msg2223564

[LittleWheelsandBig]

Ultegra hub flange cracking is starting to look like a trend, rather than just an isolated incident.

[Oxford_Guy]

Personally I think 30,000 kms is a reasonable if not stellar return.  I'd be irritated but not deterred as flanges do occasionally, very occasionally, fail.   If, other than this failure the hub has been a reliable servant, then I'd probably replace like with like.

Shimano replied my tweet, and I'm working with the local distributor.
Hope I'll have good news soon.

If I won't be able to get it replaced - I'll probably buy a new Ultegra, or ask for recommendations as in the original post.

Hope make very nice hubs for not completely silly money and offer fantastic customer service. I'm on my second Hope rear hub on my Hewitt Cheviot tourer, but the first one did 8 years of hard service before it finally developed a crack (unlike my original XT hub, which lasted less than a year before seizing). The Hope Hub I have now is the RS4 road hub (36 hole version), which is even smoother and nicer than the original Hope hub I had: http://www.hopetech.com/product/rs4-road-rear-hub/

[rogerzilla]

Are they still forging them?  I wouldn't be surprised if they'd moved to casting to save costs.  Shimano pull some pretty cheap tricks these days.

[Si S]

Personally I think 30,000 kms is a reasonable if not stellar return.  I'd be irritated but not deterred as flanges do occasionally, very occasionally, fail.   If, other than this failure the hub has been a reliable servant, then I'd probably replace like with like.

Shimano replied my tweet, and I'm working with the local distributor.
Hope I'll have good news soon.

If I won't be able to get it replaced - I'll probably buy a new Ultegra, or ask for recommendations as in the original post.

Hope make very nice hubs for not completely silly money and offer fantastic customer service. I'm on my second Hope rear hub on my Hewitt Cheviot tourer, but the first one did 8 years of hard service before it finally developed a crack (unlike my original XT hub, which lasted less than a year before seizing). The Hope Hub I have now is the RS4 road hub (36 hole version), which is even smoother and nicer than the original Hope hub I had: http://www.hopetech.com/product/rs4-road-rear-hub/

Which goes to show how experiences vary, multiple sets of bottom bracket bearings that lunch themselves in a few thousand miles, a hope freehub body that's so notched cassettes won't fit properly, a hub flange that cracked on it's second rim.

Customer services helpful? Not a hope, freehub bodies are supposed to do that, it's just aesthetic 

When I bought the Ti bike it was supplied with a Hope headset, I told the LBS to bin it.

That said I've a pair of vision 1's which have been faultless, assuming you ignore the design 'features'.

Never again.

[Oxford_Guy]

Personally I think 30,000 kms is a reasonable if not stellar return.  I'd be irritated but not deterred as flanges do occasionally, very occasionally, fail.   If, other than this failure the hub has been a reliable servant, then I'd probably replace like with like.

Shimano replied my tweet, and I'm working with the local distributor.
Hope I'll have good news soon.

If I won't be able to get it replaced - I'll probably buy a new Ultegra, or ask for recommendations as in the original post.

Hope make very nice hubs for not completely silly money and offer fantastic customer service. I'm on my second Hope rear hub on my Hewitt Cheviot tourer, but the first one did 8 years of hard service before it finally developed a crack (unlike my original XT hub, which lasted less than a year before seizing). The Hope Hub I have now is the RS4 road hub (36 hole version), which is even smoother and nicer than the original Hope hub I had: http://www.hopetech.com/product/rs4-road-rear-hub/

Which goes to show how experiences vary, multiple sets of bottom bracket bearings that lunch themselves in a few thousand miles, a hope freehub body that's so notched cassettes won't fit properly, a hub flange that cracked on it's second rim.

Customer services helpful? Not a hope, freehub bodies are supposed to do that, it's just aesthetic 

Actually that is one problem I found with Hope rear hubs (free hub notching) - never use the Alloy freehub bodies, always go for steel ones, at least for Shimano cassettes. No problem when using the steel free hub bodies.

The Hope bottom bracket I've got on the same bike has been absolutely fine, though have only done about 3000 miles on it so far.

When I bought the Ti bike it was supplied with a Hope headset, I told the LBS to bin it.

I don't have any experience of Hope headsets, I'm still on the original Cane Creek one that came with the bike (it's now 9 years old), which has never presented any problems.

[Si S]

Actually that is one problem I found with Hope rear hubs (free hub notching) - never use the Alloy freehub bodies, always go for steel ones, at least for Shimano cassettes. No problem when using the steel free hub bodies.

The Hope bottom bracket I've got on the same bike has been absolutely fine, though have only done about 3000 miles on it so far.

It'll be interesting to see how you get on with the BB, I could have stuffed up the initial installation, unlikely but I do have form for being a gorilla wivva a spanner, but when I bought the new bearings I took it to someone who knew what he was doing, YKWYA. IIRC correctly Flatus had major issues with a Hope ceramic BB.

The freehub thing is disappointing, it's clearly not just aesthetic when one sprocket has cut 50% of the way through the splines, at some point it's just going to spin uselessly. As you say Hope's answer is to buy a SS one at  ££

[tkatzir]

Personally I think 30,000 kms is a reasonable if not stellar return.  I'd be irritated but not deterred as flanges do occasionally, very occasionally, fail.   If, other than this failure the hub has been a reliable servant, then I'd probably replace like with like.

Shimano replied my tweet, and I'm working with the local distributor.
Hope I'll have good news soon.

If I won't be able to get it replaced - I'll probably buy a new Ultegra, or ask for recommendations as in the original post.

Stay tuned...

I got a reply from the local Shimano distributor:
It's 3.5 years old, and has 2 years warranty. You should be happy it lasted that long.

I guess I'll buy the same Ultegra 32 holes.

[LittleWheelsandBig]

Why not tell your Shimano distributer that you want more than 2 years service out of a hub and purchase a different brand of hub instead? I think that is a particularly shit response. Who else does cold-forged hubshells, Novatec?

EDIT - yup https://m.pinkbike.com/news/Making-a-Novatec-Hub-2013.html

[tkatzir]

Why not tell your Shimano distributer that you want more than 2 years service out of a hub and purchase a different brand of hub instead? I think that is a particularly shit response. Who else does cold-forged hubshells, Novatec?

Dura-Ace is 3 years. I don't believe Dura-Ace is worth that kind of $$$, since I got more than 3 years lifespan from an Ultegra, which is less than half the price.

I know Chris King offer 5 years warranty on their R45 rear hub, but that costs about 3 times as much as a Dura-Ace.
If I'll buy a Chris King it will be when I know they support the next-after-11-speed Shimano cassettes (seeing where this world is deteriorating into...)

[Samuel D]

Dura-Ace is 3 years. I don't believe Dura-Ace is worth that kind of $$$, since I got more than 3 years lifespan from an Ultegra, which is less than half the price.

I’d go the other way with a 105 or even Tiagra hub in the hope that they’re equally well designed and perhaps not trying to save the last gram of weight; and if they’re no better, at least they’re cheaper.

But there are few complaints about Shimano hubs failing in this way despite the colossal number of Shimano hubs in use.

I’m sure Shimano would be interested to hear the distributor’s comment above. Three years is a pathetic lifespan for a hub although a combination of unfortunate events rather than a design flaw may have led to the early demise of this particular example.

[tkatzir]

Dura-Ace is 3 years. I don't believe Dura-Ace is worth that kind of $$$, since I got more than 3 years lifespan from an Ultegra, which is less than half the price.

I’m sure Shimano would be interested to hear the distributor’s comment above. Three years is a pathetic lifespan for a hub although a combination of unfortunate events rather than a design flaw may have led to the early demise of this particular example.

The distributor said that this was Shimano's reply.
I've let Shimano know, in this Tweet.

[LittleWheelsandBig]

There are some worthwhile 32 hole hubs listed in https://yacf.co.uk/forum/index.php?topic=97652.msg2031814#msg2031814

[zigzag]

if you go for the same, you can still re-use old hub's axle assy, bearings and freehub (if they still work fine) and save the new ones for the future