Shimano hubs: flange damage

[crg]

Rohloff hubs are susceptible to breaking of flange due to pressure from spokes.

Any such reports about Shimano Nexus and Alfine hubs?

[pwa]

None of mine have broken in that way. But nor has my Rohloff.

I once had Miche hub that had a flange crack, but that was one hub in 55 years and many thousands of miles of cycling, so I suggest that it isn't a problem most of us experience very often.

[andrew_s]

It's uncommon with Shimano hubs, but can happen

(XT FH-M756, 8/9/10 speed, iirc)

The basic difference between Shimano and most other brands is that Shimano hubshells are forged, rather than machined from a solid block like most others. Metal has a "grain", somewhat like wood, and in a forged item, the line of the grain is reshaped to follow the forging, rather than following the line of the billet the hub was machined from. This makes Shimano hubs less likely the crack than many others.

[pliptrot]

I had a similar failure with a Hope hub ((very) small flange). Hope told me it must be down to neglect and corrosion. Hilarious, given that these were my racing wheels and never even got wet. I spend a lot on bikes, and like to support the home side, but Hope will never see a penny more of mine.

[ebor62]

I have one exactly the same in my garage. 9 speed drive side built into a mavic A719 rim. I have used this combination for many years and have had a few due to rim wear. The rest have been perfect and this one still ran perfectly true and was hidden behind the large cog on the cassette and I only noticed it when working on my bike at home so I don't know how long it had been like that. I have often wondered if it was a faulty flange, too much weight, a bad bump or over tensioned spokes. I use the same type of hub on 4 bikes and so feel it was just bad luck rather than a weak component to be avoided.

[pedalsheep]

I had a similar failure with a Hope hub ((very) small flange). Hope told me it must be down to neglect and corrosion. Hilarious, given that these were my racing wheels and never even got wet. I spend a lot on bikes, and like to support the home side, but Hope will never see a penny more of mine.

I also had a very small flange Hope front hub break taking 4 spokes with it. Hope told me the spokes must have been too tight. Their customer service really is second to none!

[cycle tramp]

Anecdotally Hope hubs were known for flange breakages - their hubs were machined from blocks of alloy.. I so wonder if bicycle riders wouldn't be better in accepting a small amount of surface rust, and going back to steel hubs

[axel_knutt]

I had a similar failure with a Hope hub

I recall reading an article by CJ in the CTC Mag about Hope hubs failing more than Shimano because....

Shimano hubshells are forged, rather than machined from a solid block like most others.

[rogerzilla]

I had a section of flange rip off a Goldtec hub, with four spokes coming free Again, a machined, not forged, shell. Caused by salt corrosion, I believe, as it was a commuter bike and the oily RH flange was fine. It was on its third winter and had only done about 7000 miles.

[rogerzilla]

Anecdotally Hope hubs were known for flange breakages - their hubs were machined from blocks of alloy.. I so wonder if bicycle riders wouldn't be better in accepting a small amount of surface rust, and going back to steel hubs

Steel hubs were mostly rubbish for other reasons - they were usually 3-piece, with less accurate alignment of bearings and spoke holes, and they support the spoke elbows less well as they are too hard and the flanges are too thin.

Aluminium hubs are fine if forging is used, but forges are big and expensive, so only accessible to the volume manufacturers.

[drossall]

I've had it with, from memory, one Shimano and one Campagnolo hub, both screw thread (so this has long been a risk). Both had given good, long, service, and nothing lasts forever. I may also have had it with a less well-known brand.

[Cyckelgalen]

I have read some reports online of Rohloff flange failures, but they are rare or even negligible.
Rohloff and other IGH flanges are less likely to fail than regular rear hubs for a very simple reason: IGH wheels are not dished. As cassettes get more cogs, wheels have to be increasingly dished and the spokes on the drive side have to be tensioned almost double as much as the non drive side. If you add transmission torque on top of that, no wonder that some flanges fail on that side, like the M756 pictured above.
A friend of mine had exactly the same failure with a M756. It is a great hub, old school Shimano XT with steel axle, but those silly weight saving cutouts certainly weaken the flange.

[Norman H]

Looking at the photo of the failed M756 hub above I'd bet that corrosion played a big part in its failure.

[borisface]

You don't want to injure your flange

[MikeF]

Looking at the photo of the failed M756 hub above I'd bet that corrosion played a big part in its failure.

My thoughts too