Author Topic: Rohloffs redesigned  (Read 9910 times)

Wowbagger

  • Dez's butler
    • Musings of a Gentleman Cyclist
Rohloffs redesigned
« on: November 06, 2009, 09:54:15 am »
I've just received my 4th Rohloff for the tandem, having broken the previous three.

The flanges on the new one have far more metal in them and also have a thickened "rim" to the flange.

This one has also been laced so that (it would appear at least) the bolt thickening areas will take the spoke stresses.

I've got a feeling it will be a long time before we break this one.



Rohloff dating from 2006



2009 Rohloff. (Phwooar! Look at the flanges on that!)
Whaddawewant? Gratification! Whendowewannit? Not just yet...

LEE

Re: Rohloffs redesigned
« Reply #1 on: November 06, 2009, 10:02:03 am »
I heard that Rohloff Germany had been working on "Project WB" for some months.

Re: Rohloffs redesigned
« Reply #2 on: November 06, 2009, 10:02:34 am »
I really hope that they've fixed it for you this time wow.  I think you have been more than patient - possibly because you like the rest of the tandem?

LEE

Re: Rohloffs redesigned
« Reply #3 on: November 06, 2009, 10:49:11 am »


2009 Rohloff. (Phwooar! Look at the flanges on that!)

That's a lot of metal between spoke and the outside World now. 

Is that the standard new hub?  I wonder how much weight it added.

Oscar's dad

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Re: Rohloffs redesigned
« Reply #4 on: November 06, 2009, 10:50:34 am »
Spot on!  Even to the untutored eye (like mine) you can see the difference in design.  Also it's good to see they have followed your logic when it comes to lacing the wheel.  

You and Mrs Wow now need to spend the winter seeing if you can break it - have fun!

dasmoth

  • Techno-optimist
Re: Rohloffs redesigned
« Reply #5 on: November 06, 2009, 10:51:53 am »
It's enough that it could well make the difference, but I doubt it weight that much -- still Aluminium, right?

Anyway, hope it performs well.
Half term's when the traffic becomes mysteriously less bad for a week.

Re: Rohloffs redesigned
« Reply #6 on: November 06, 2009, 10:57:23 am »
It's clearly the stokers wow's had on the back that is the problem. Firm young thighs rhythmically thrusting the pedals up and down,  up  and  down,   up   and   down,    up    and    down,     up    and     down...  :P

Adam

  • It'll soon be summer
    • Charity ride Durness to Dover 18-25th June 2011
Re: Rohloffs redesigned
« Reply #7 on: November 06, 2009, 11:00:35 am »
Hopefully that will do the trick.

However, on the new one - is the extra metal part of the hub itself, or is it simply a circular band of metal sandwiched over the rim of the old hub?  If it's the latter, then I'm not so sure it would help much.
“Life is like riding a bicycle. To keep your balance you must keep moving.” -Albert Einstein

Re: Rohloffs redesigned
« Reply #8 on: November 06, 2009, 11:56:10 am »

However, on the new one - is the extra metal part of the hub itself, or is it simply a circular band of metal sandwiched over the rim of the old hub?

I reckon they've had a circular nibble at the die-casting tool, and there's now more metal to the flange casting.
If it was a press fitted metal band or ring, do you not think there'd be more of the radius of the original flange-edge visible in the updated version?

Good luck with it, Wow.

Re: Rohloffs redesigned
« Reply #9 on: November 06, 2009, 01:56:35 pm »
I suspect even an additional band around the flange would help reinforce it, but it looks like additional material on the entire casting.

I'll admit I'm not convinced about Wow's justification for moving the spokes.  There may be more metal there to take the strain, but it doesn't look like there's a lot more actually directly between the spoke hole and the edge of the flange, along the line which the force will be acting.

I suspect working out how a shape like this is effected by the various stresses and strains imposed upon it, is largely beyond looking at it and deciding what is happening, and probably requires some fairly hairy computer modelling to get a definitive answer.

It may just be that reorienting the spokes does place less stress on a weakened location, but I'd hate to have to justify this rigorously.

Time to wait and see if this works or not.  Hopefully it's a more permanent solution.
Actually, it is rocket science.
 

Wowbagger

  • Dez's butler
    • Musings of a Gentleman Cyclist
Re: Rohloffs redesigned
« Reply #10 on: November 06, 2009, 02:54:25 pm »
http://peter.chesspod.com/rohloff/cracks-big.jpg is the hub we broke and sent back in Feb 2008. It's a big jpg which is why I haven't embedded it.

There are 7 cracks in that and they are all trailing spokes on the non-drive side. All of those cracks in the new lacing pattern would have to go through the thick metal chunks where the bolts go. Furthermore, the extra alloy, which is integral but appears as a thickened band, does not appear to have been machined. The drive side also has one (silly not to if you are redesigning the shell anyway).

 I'll be most surprised if we can break this one.

Whaddawewant? Gratification! Whendowewannit? Not just yet...

Wowbagger

  • Dez's butler
    • Musings of a Gentleman Cyclist
Re: Rohloffs redesigned
« Reply #11 on: November 06, 2009, 03:22:41 pm »
I sent this to Robin Thorn this morning:-

Quote
The wheel, with new Rohloff, arrived this morning - thanks.

I notice that Rohloff have redesigned their hubs and that the flanges  
appear to be much more robust - there must be between 2 and 3 mm of  
extra metal there.

Hopefully, this hub should see us out!

and had this reply:

Quote
No, that's not the case, what you're seeing is an EXTRA ring that we now fit
to tandem builds, it's designed to keep the flange in place in the
(unlikely!!!) event of a flange failure!!

Incidentally, you had managed to crack the rim, near the join, this is
something we've NEVER seen on a Rigida Andra30 so I'm hopefull that you must
be our "hardest" customer for wheels!!!

I thought, as I was fitting the wheel to the bike just now, "that looks like a new rim". Blimey! I was right!

Edit: the Rigida Andra 30 is the rim that's reinforced with tungsten carbide.
Whaddawewant? Gratification! Whendowewannit? Not just yet...

Oscar's dad

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Re: Rohloffs redesigned
« Reply #12 on: November 06, 2009, 03:28:41 pm »
^^^ That's quite some accolade!  You're Thorn's best / worst tandem customer!

alan

Re: Rohloffs redesigned
« Reply #13 on: November 06, 2009, 03:28:48 pm »
I am pleased for you Wow that RT is in tandem :facepalm: with you to satisfy you,the customer.

clarion

  • Tyke
Re: Rohloffs redesigned
« Reply #14 on: November 06, 2009, 03:29:51 pm »
Let's hope Robins flange & ring are enough to satisfy Wowbagger.
We are all just prisoners here of our own (mobile) device.

Re: Rohloffs redesigned
« Reply #15 on: November 06, 2009, 03:40:01 pm »
>wowbagger  - is the ring just a tight machined interference fit or do the star bolts go though and secure it ?  I've not really looked at a Rohloff so don't know what it looks like on 'tuther side.

Re: Rohloffs redesigned
« Reply #16 on: November 06, 2009, 04:09:02 pm »
Yikes, you cracked the rim as well. :o

I'm guessing they'll have replaced all the spokes as well (since they are cheap, and will also have possibly been excessively strained once the hub broke), so I assume they've just given you a new wheel from their stock, since everything will have needed replacing.

I suppose the rim damage could simply have been a cascade failure because of additional strains on adjacent spokes to the failed one (or more exactly the spoke connected to the hub at the failure point).
Actually, it is rocket science.
 

Adam

  • It'll soon be summer
    • Charity ride Durness to Dover 18-25th June 2011
Re: Rohloffs redesigned
« Reply #17 on: November 06, 2009, 04:27:05 pm »
I sent this to Robin Thorn this morning:-

Quote
The wheel, with new Rohloff, arrived this morning - thanks.

I notice that Rohloff have redesigned their hubs and that the flanges  
appear to be much more robust - there must be between 2 and 3 mm of  
extra metal there.

Hopefully, this hub should see us out!

and had this reply:

Quote
No, that's not the case, what you're seeing is an EXTRA ring that we now fit
to tandem builds, it's designed to keep the flange in place in the
(unlikely!!!) event of a flange failure!!

Incidentally, you had managed to crack the rim, near the join, this is
something we've NEVER seen on a Rigida Andra30 so I'm hopefull that you must
be our "hardest" customer for wheels!!!

I thought, as I was fitting the wheel to the bike just now, "that looks like a new rim". Blimey! I was right!

Edit: the Rigida Andra 30 is the rim that's reinforced with tungsten carbide.

A nice shiny ring piece from Robin Thorn.

That confirms what I thought initially, in that it's an extra band of metal they've put on.  Still, if it does the job.

Where's your next expedition going to be?  A bit of off-roading?
“Life is like riding a bicycle. To keep your balance you must keep moving.” -Albert Einstein

Re: Rohloffs redesigned
« Reply #18 on: November 06, 2009, 04:29:19 pm »
Sounds like Thorn wheels with Rohloffs are pretty crap if ONE user can break three of them. That Scottish fellow who rode round  the world broke his Rolhoff wheel to didn't he ? Ok, we don't hear of the millions of satisfied users but that would be no comfort to me if my wheel broke when halfway up the hindu kush

clarion

  • Tyke
Re: Rohloffs redesigned
« Reply #19 on: November 06, 2009, 04:30:22 pm »
If that's an added ring rather than an enlarged casting, I do not have faith that it solves the problem.*



* IANAMetallurgist
We are all just prisoners here of our own (mobile) device.

Re: Rohloffs redesigned
« Reply #20 on: November 06, 2009, 04:41:29 pm »
If that's an added ring rather than an enlarged casting, I do not have faith that it solves the problem.*



* IANAMetallurgist

I am also not an hexpert.  But as soon as I saw they were adding the ring I winced.

Winter salt?  Damp creeping in between the hub and ring? Corrosion city?

Re: Rohloffs redesigned
« Reply #21 on: November 06, 2009, 04:43:59 pm »
^ nor am i but that was my thinking when I asked if the ring was bolted or interference.  Looks like it is intended to stop cracks spreading too far and also to stop bits of flange flying off.  

clarion

  • Tyke
Re: Rohloffs redesigned
« Reply #22 on: November 06, 2009, 05:15:29 pm »
Yes, but my dad (and he be a metallurgist of the top hole sort) reckons that an overlap like that can hide damage, which means things get worse.
We are all just prisoners here of our own (mobile) device.

Re: Rohloffs redesigned
« Reply #23 on: November 06, 2009, 05:33:40 pm »
But as soon as I saw they were adding the ring I winced.


It doesn't really inspire confidence.
Rohloff are saying that they make unbreakable hubs with a lifetime guarantee.
But we just added this bit, just incase our unbreakable hub should, ahem, break. (shifty quick smile)

Anyway, I hope that wowbagger proves me wrong and that it lasts for at least another 200,000 miles trouble free.

Was the rim that cracked from the original wheels? I wonder if the rim breaking had anything to do with stresses caused by the broken hub flange?

Re: Rohloffs redesigned
« Reply #24 on: November 06, 2009, 05:45:39 pm »
The flange does seem to be a weak point. Here's another one that broke (on the other side this time) on a world tour (scroll down a bit): isaetterry equipment

Interesting with the lacing. The Rohloff manual (p.125) tells you to lace it like Wow's 2006. So, the 2009 lacing goes against this. My new 2009 Raven Nomad is laced like Wow's new 2009 hub. Maybe Thorn have decided to do it this way now?

Thorn's add-on looks a bit 'sticking plaster-ish' to me. Hope it holds for you...

Shaun
(Hoping my flange doesn't let go)