Rohloff Speedhub flange support rings.

[EdT]

I would have thought that casting and machining would be more likely, but equally inferior to a forged construction.

[alastairwb]

rohloff, like many other 'boutique' hub makers, cannot sensibly use forged flanges for their hubs, they must be machined from billet instead. Unfortunately the transverse properties become less and less well defined in bigger sections of billet, ultimately leaving the Al hubshell vulnerable to cracking. A method by which this may be avoided is to use flanges made from sheet material, which has altogether more dependable transverse properties.

As always a thought provoking suggestion. A couple of questions:
1. Just trying to picture what you are suggesting. Would this be a cylindrical hub centre section with 2 flanges made from sheet material joined to the centre section at each end ?
2. What do you think is the balance of advantage between a single monolithic machined part versus a more complex multipart component?

[cycle tramp]

rohloff, like many other 'boutique' hub makers, cannot sensibly use forged flanges for their hubs, they must be machined from billet instead. Unfortunately the transverse properties become less and less well defined in bigger sections of billet, ultimately leaving the Al hubshell vulnerable to cracking. A method by which this may be avoided is to use flanges made from sheet material, which has altogether more dependable transverse properties.

Yeah, absolutely... personally i'd imagine an alloy hub shell, with the equivelant of two larger diameter 'disc brake' mounts (one at each end) to which are bolted, stainless steel wheel flanges. This could mean that every part of the hub shell was replaceable.and may allow the manufacturer an opportunity to produce flanges in different sizes to suit different rim diameters

I guess if we continue the idea, we could join the two flanges by way of long connecting rods and sit the hub inside it. This would allow the hub to seperate from the wheel (whilst leaving it intact) meaning that either hub or wheel failures could be effectively dealt with (by replacing either) it would also allow any touring cyclist the opportunity of carrying a complete spare hub which could be fitted in a matter of minutes..

[Victor]

Are cheap hubs such as Joytech forged? I suspect they are. It makes you wonder if there is any value at all in the 'boutique' brands. OK, the Rohloff might be the best (or least troublesome) hub gear, but they obviously have some deficiencies, which for the money, is a shame.

[Carlton green]

I suspect, but don't know for sure, that the Rohloff hub shell is machined out of an aluminium alloy bar rather than forged.

The picture on the Rohloff site suggests to me that it’s some form of casting and would be rather wasteful to machine from solid bar. https://www.rohloff.de/en/products/speedhub/

I'd probably choose a Shimano Alfine 8 or derailleurs, but I'm a cheapskate.

Yep, me too, though I can easily see why some people choose to invest a lot more in a Rohloff.

OK, the Rohloff might be the best (or least troublesome) hub gear, but they obviously have some deficiencies, which for the money, is a shame.

Which is my point really, for the money I’d expect that they’d get the simple stuff right.

[PT1029]

I expect if Rohloff knew they would end up selling as many hubs as they now do, they might have gone to the expense of having forged hub shells. But as they started off selling far fewer hubs than they do now, milling from billet was probably the only economic was to go.

NB Re getting flanges fitted, they are period dependant (the hub shell has been tweeked slightly over the years), so you need to know your hub serial number.

[pwa]

Are cheap hubs such as Joytech forged? I suspect they are. It makes you wonder if there is any value at all in the 'boutique' brands. OK, the Rohloff might be the best (or least troublesome) hub gear, but they obviously have some deficiencies, which for the money, is a shame.

The big selling point for the Rohloff (for me) was the gear range. Nothing else in hub gears comes close. If you really want a range close to what you might get on a derailleur equipped mountain bike, Rohloff does it. You can have that super-low twiddling gear for steep hills and still have a decent downhill gear, and everything in between.

[cycle tramp]

Which is my point really, for the money I’d expect that they’d get the simple stuff right.

Hindsight is a wonderful thing and if i had it i would give it away to everyone else...(Hey, i might vote for Trump.... Here have somehindsight... oh S-! Perhaps i won't) most product ideas come from a number of movated and committed individuals.. the chances of them attempting to replicate all eventualities which might have caused flange damage are silm.. especially if the flange damage is caused by a situation along the lines of 'Hey i loaded my bike up with 40kgs of camping gear and rode it down a stoney off road track at 40 mph and now the hub is broken'

To my mind the whole thing about hubs in the centre of wheels is a non-starter anyway.. because by now the cycle industry should have been clever enough to have placed the hub in the frame, seperate from the wheel.. certainly with recumbent bikes and trikes, and even long and mid tail cargo there is already the space to do that. This would allow for a mono stay rear wheel support and an oilbath chainset, further to this it would also allow the wheel bearings to be mounted in the frame, rather than the wheel hub itself allowing the wheel bearings to be twice maybe even three times the diameter they are now, for strength and longevity

As for Shimano and Sturmey Archer, Rolhoff's crowning achievement was to place the gear selector at the hub end, where it was completely uneffected by stretched cables and was always indexed.... suddenly everything else looked like it was designed on a friday afternoon before a bank holiday...

But its a free world... if any thinks they can make a better hub, there's noone stopping you

[rareposter]

Which is my point really, for the money I’d expect that they’d get the simple stuff right.

There are plenty of examples in the engineering world of building a product, all seems fine and then a flaw is discovered and the cheapest, easiest most cost-effective way of fixing it is to produce A Thingy to mitigate the problem, not do a full recall, redesign and rebuild.

Not related to hubs but the pedestrian bridge over the Thames which wobbled at certain frequencies is a good example - they had to go back and fit dampers to it. Much easier than ripping it down and rebuilding!

I had a Goldtec SS hub which broke at the flange when it was being built into probably it's third wheel.

[rogerzilla]

Goldtec hubs don't like road salt. The flange on mine cracked into its second winter of comnuting, and they wouldn't replace it. The summer-use only ones are over 20 years old and still intact.

[Carlton green]

Which is my point really, for the money I’d expect that they’d get the simple stuff right.

There are plenty of examples in the engineering world of building a product, all seems fine and then a flaw is discovered and the cheapest, easiest most cost-effective way of fixing it is to produce A Thingy to mitigate the problem, not do a full recall, redesign and rebuild.

Not related to hubs but the pedestrian bridge over the Thames which wobbled at certain frequencies is a good example - they had to go back and fit dampers to it. Much easier than ripping it down and rebuilding!

I had a Goldtec SS hub which broke at the flange when it was being built into probably it's third wheel.

It’s true, a noticeable amount of new stuff fails in service; mostly the customers aren’t very pleased and regard such stuff as being not of merchantable quality - doesn’t do much for the brand name either. When something is a cutting edge design then failure of new technology is, to some extent, understood to be a possibility. In this case what we’re talking about is spoke holes in a flange, and that’s long established usage so obviously not new technology.

Failure of the Goldrec hub in its third wheel seems more reasonable to me: it’d had a long life and significant usage, and it was so expensive as to expect an indefinite life. Of course failures happen for a multitude of reasons and it’d be interesting to know what Rohloff has done to more recent hubs to prevent flange failures.

Hindsight is a wonderful thing and if i had it i would give it away to everyone else...(Hey, i might vote for Trump.... Here have somehindsight... oh S-! Perhaps i won't) most product ideas come from a number of movated and committed individuals.. the chances of them attempting to replicate all eventualities which might have caused flange damage are silm.. especially if the flange damage is caused by a situation along the lines of 'Hey i loaded my bike up with 40kgs of camping gear and rode it down a stoney off road track at 40 mph and now the hub is broken'

But its a free world... if any thinks they can make a better hub, there's noone stopping you

Hindsight is indeed wonderful, it’s usually a good idea to look at what went right and wrong in the past and then to learn from those events.

It’s interesting to observe that the spoke loads on hub gears are at least typically much less than those seen on the drive side of derailleur geared hubs. Unless I’m mistaken there isn’t an issue with those more highly loaded derailleur hub flanges breaking and people do give the associated wheels all sorts of abuse. I mention price differences above.

A few people have already come up with alternative shell designs, and I suspect that Rohloff are sufficiently content with the ‘solution’ that they have put in place. To be fair the ‘solution’ has a lot going for it but imho, for a product of this price, it should be supplied for either free or a token price (so much less than the current price of circa £25).

[PH]

Which is my point really, for the money I’d expect that they’d get the simple stuff right.

I think you may have misjudged how simple it was, forging was never an option and there's no evidence that Rohloff hubs crack any more than other machined hubs.
That's not to say they got it as good as possible straight off, there was some trial and error, they changed the shell design a couple of times (At one time the flanges were a different diameters) commissioned a spoke to specifically match the hub, introduced the rings. Rohloff now claim to be confident that flange breakages won't occur if their spokes are used and their building instructions are followed. Thorn go a step further and guarantee the flanges on wheels they build for ten years.

[rareposter]

To be fair the ‘solution’ has a lot going for it but imho, for a product of this price, it should be supplied for either free or a token price (so much less than the current price of circa £25).

They're precision made heat-shrunk flanges, specific to the hub design (which is why you need the serial number). I'm willing to bet that £25 is basically cost price; it's also less than 2% the cost of a Rohloff hub.

I thought from the way you were complaining about the additional cost it was going to be a couple of hundred quid, not £25!

[Carlton green]

Which is my point really, for the money I’d expect that they’d get the simple stuff right.

I think you may have misjudged how simple it was, forging was never an option and there's no evidence that Rohloff hubs crack any more than other machined hubs.
That's not to say they got it as good as possible straight off, there was some trial and error, they changed the shell design a couple of times (At one time the flanges were a different diameters) commissioned a spoke to specifically match the hub, introduced the rings. Rohloff now claim to be confident that flange breakages won't occur if their spokes are used and their building instructions are followed. Thorn go a step further and guarantee the flanges on wheels they build for ten years.

Having worked in R&D those restrictions all rather smack of a product that’s really not quite right but can be made to work if particular restrictions on use are imposed. To be fair to Rohloff they have a product that’s excellent in nearly all respects and they set the standard by which other hub gears are judged.

The more I think about it the more I like the rings idea. It’s simple, (relatively) cheap, ‘could’ effectively stop crack propagation, and ‘could’ impede spokes pulling the flange out of shape (‘could’ because to load share it needs to be a tight fit on the flange).

Whatever, discussion here won’t change anything and I wish those who have a Rohloff many happy years of use.

[rogerzilla]

What's really remarkable is that Sturmey-Archer made alloy-shelled versions of their "sporty" hubs in the 1950s and didn't change the dimensions, although aluminium is far weaker than steel. Some of these have never cracked. I've been riding one for 17 years, and it had presumably been well-abused before that.

The current SA alloy shells are much beefed-up but manage to weigh more than the chromed steel ones did. The old alloy ones were 4oz lighter than steel, IIRC.