VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please?

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Brucey
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by Brucey »

machining hubshells from certain bar stock is indeed a dumb idea and forged shells would indeed be a better idea.

However the spoke holes are so far apart in a Rohloff hubshell that the idea that a 36h shell will be significantly weaker than a 32h one doesn't hold water; you would have to be talking about a flange diameter about 1/3 the size or something like that before it ought to be significant. The cracked Rohloff flanges I have seen have usually cracked outwards rather than to the neighbouring spoke holes, but in reality they will crack wherever there is an inclusion or other weakness in the material, and a primary driver for the failures is the tension per spoke.

[NB if you bother to do an analysis of the stresses around spoke holes you will find that they are dominated by the uneven loading applied by the spoke itself; the idea that moving a hole a little (that is already several hole diameters away) is going to alter these stresses very much is not one that makes much sense, even once you allow for the small change in approach angle. The holes are about 1mm closer together in a 36h rohloff hub vs a 32h one, and either way they are much further apart than holes are in lots of other perfectly robust bike hubs.

Similarly if they wanted the flanges to last longer, they'd drill the holes smaller; IIRC they are 2.5mm at present, and if you stick a 2mm spoke in a 2.5mm hole, you will inevitably end up with more concentrated stresses than if the same spoke were in a smaller hole. If you are then dumb enough to spec a 'high strength' flange material, the spoke won't ever bed itself in which would otherwise serve to reduce the stress concentrations. ]

[It wouldn't surprise me to find out that they have chosen poorly with the material BTW; a lot of engineers are rather poor materials scientists and are all too happy to believe the axial properties of bar stock are the same as the transverse properties (they are not, nothing like in fact, and the fatter the bar stock is, the worse it gets); also the niceties of corrosion-related failures are often ignored too. ]

In addition the hubshells in a 36h wheel are (for any given wheel strength, or stiffness) somewhat less stressed than in a 32h wheel. Both the static stress per hole and the dynamic stress per hole can be reduced if appropriate spokes are used. Since the 'net damage' to the hub is to some extent a product of both effects, a 15% change in each (say) could result in a net benefit of over 30%.

Obviously if you go to the same spoke gauge/tension per spoke in a 36h wheel the wheel itself will be appreciably stronger, but also it will suffer less fatigue damage still because the cyclic stresses in the spokes will still be lower than in a 32h wheel.

There is an awful lot of misunderstanding out there about how wheels work and what is and isn't a good idea, but it is very, very rarely the case that using more spokes is a 'bad idea'.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
maxglide
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by maxglide »

They build a round-the-world tank, then go and put 700 wheels on it.
pete75
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by pete75 »

maxglide wrote:They build a round-the-world tank, then go and put 700 wheels on it.


They do the TX400 which is similar but with 26" wheels.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
Des49
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by Des49 »

Brucey wrote:machining hubshells from certain bar stock is indeed a dumb idea and forged shells would indeed be a better idea.

However the spoke holes are so far apart in a Rohloff hubshell that the idea that a 36h shell will be significantly weaker than a 32h one doesn't hold water; you would have to be talking about a flange diameter about 1/3 the size or something like that before it ought to be significant. The cracked Rohloff flanges I have seen have usually cracked outwards rather than to the neighbouring spoke holes, but in reality they will crack wherever there is an inclusion or other weakness in the material, and a primary driver for the failures is the tension per spoke.

.........

There is an awful lot of misunderstanding out there about how wheels work and what is and isn't a good idea, but it is very, very rarely the case that using more spokes is a 'bad idea'.

cheers


Thanks Brucey for this info.

If I am ever looking for another Rohloff then I will try to get a 36 hole model. Every wheel I use myself has 36 spokes, except for the one Rohloff. But so far it has proved highly reliable, being on 26" helps.

I do like the idea of those flange support rings though.
bretonbikes
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by bretonbikes »

Funnily enough I've just reviewed the bottom of the range VSF bike, the 50s. The one thing that shone out with it is the way no corners were cut, even on a relatively cheap bike - sure you don't get XT, but it's the little things like the Allen bolts being stainless, good quality cables, the quality of the build kit, even the box they were delivered in and the factory set-up (are you listening Dawes!!!). I'm a real cynic but i was hugely impressed especially at the price thanks to the weak Euro - http://www.bretonbikes.com/homepage/cyc ... e-vsf-t50s

I bought it because I was looking for a replacement for our hire bikes and wanted to see what sort of company they were to deal with and gauge from a cheap bike what the quality was like. I was hugely impressed with every aspect and I'm starting to understand what 'Tutonic efficiency' means. The bike came packed in a specially made cardboard protective sleeve then in a bike box. Dawes equivalent comes with about 20 bits of corrugated cardboard zip tied and masking taped up bits - it must cost more to do than the VSF solution and is a pain in the bum.

Anyway I then investigated the TX-1000 and both Rohloff and TX-400 XT and both are superb bikes and every single component is top notch. They are not cheap but count up the kit and they seem very good value. In the end we decided to go for the Ridgeback Expedition, maily because the VSF's like many German bikes seemed loaded with everything including the kitchen sink and the Ridgeback in its quality and simplicity was just perfect for us - viewtopic.php?f=16&t=102043&hilit=ridgeback+expedition
38 years of cycletouring, 33 years of running cycling holidays, 8 years of running a campsite for cyclists - there's a pattern here...
PH
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by PH »

bretonbikes wrote:the VSF's like many German bikes seemed loaded with everything including the kitchen sink and the Ridgeback in its quality and simplicity was just perfect for us - viewtopic.php?f=16&t=102043&hilit=ridgeback+expedition

Yes, I know it's seen as a plus to get the bike with all the extras included, but for me part of the fun of a new bike is choosing those myself, it's not that I don't want the kitchen sink on a touring bike but I might not choose the same one as the manufacturer.
bretonbikes
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by bretonbikes »

PH wrote:
bretonbikes wrote:the VSF's like many German bikes seemed loaded with everything including the kitchen sink and the Ridgeback in its quality and simplicity was just perfect for us - viewtopic.php?f=16&t=102043&hilit=ridgeback+expedition

Yes, I know it's seen as a plus to get the bike with all the extras included, but for me part of the fun of a new bike is choosing those myself, it's not that I don't want the kitchen sink on a touring bike but I might not choose the same one as the manufacturer.


One of the weaknesses for me of the whole range is that every bike they make has a hub-dyno/lighting. The thing it that as far as I'm concerned the world has moved on - modern LED lights just don't need the dynamo and it's a huge load of complication I could do without, and yet for all moanufacturers of touring or city bikes in germany it is the first thing that get's specced. i even asked if they could supply the 400 without all the lighting and they said 'no - not until you order in batches of 200. I mean - how difficult is it for them to just leave the bloody lights off and spec a standard front hub?

The other side of Tutonic Efficiency is that they know best and you will do what you're told...
Ho hum
38 years of cycletouring, 33 years of running cycling holidays, 8 years of running a campsite for cyclists - there's a pattern here...
bretonbikes
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by bretonbikes »

maxglide wrote:They build a round-the-world tank, then go and put 700 wheels on it.

^^^ This
38 years of cycletouring, 33 years of running cycling holidays, 8 years of running a campsite for cyclists - there's a pattern here...
fatboy
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by fatboy »

Re: hub dynamo. They will be required by German law to have a dynamo on all of their bikes unless they weigfh under 10kg (if my memory holds). However I am a huge dynamo fan and I think that battery lights still have limitations if you ride a lot at night. So for me hub dynamo would be a selling point.

By the way they do a trekking bike with Rohloff that's a bit lighter.
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly
pete75
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by pete75 »

bretonbikes wrote:
PH wrote:
bretonbikes wrote:the VSF's like many German bikes seemed loaded with everything including the kitchen sink and the Ridgeback in its quality and simplicity was just perfect for us - viewtopic.php?f=16&t=102043&hilit=ridgeback+expedition

Yes, I know it's seen as a plus to get the bike with all the extras included, but for me part of the fun of a new bike is choosing those myself, it's not that I don't want the kitchen sink on a touring bike but I might not choose the same one as the manufacturer.


One of the weaknesses for me of the whole range is that every bike they make has a hub-dyno/lighting. The thing it that as far as I'm concerned the world has moved on - modern LED lights just don't need the dynamo and it's a huge load of complication I could do without, and yet for all moanufacturers of touring or city bikes in germany it is the first thing that get's specced. i even asked if they could supply the 400 without all the lighting and they said 'no - not until you order in batches of 200. I mean - how difficult is it for them to just leave the bloody lights off and spec a standard front hub?

The other side of Tutonic Efficiency is that they know best and you will do what you're told...
Ho hum


A hub dynamo is hardly a weakness especially on a touring bike. It's not just for the lights , many people these days use usb charged devices when touring, mobile phones GPS units etc and a hub dynamo can charge these. On a multi day tour how do you charge these unless you're staying in a hotel every night. Many of the better modern day LED lights need to be recharged again how can this be done by the many tourists who camp. The self generated electricity is particularly useful for those who use a TX400 expedition bike for it's intended purpose.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
bretonbikes
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by bretonbikes »

Personally I just carry a battery pack. One like this - http://www.amazon.co.uk/RAVPower-20100m ... s=ravpower - will power lights, gps, phone. mp3 (though hopefully they are all the same) for a good fortnight and it charges stuff really quickly. You need to be very much in the wilds not to find a power point to charge it every 2 weeks...

In my case I carry one half that size and I've yet to have it run out in a fortnight's use but then I'm probably not a heavy user. They are indestructible, charge really quickly, cheap as chips and replaceable if they get nicked whilst you are charging it in campsite loos.

The point being that you have to carry the expense, complication and drag of a dyno-hub whether you need it or not - they are solving yesterday's problem IMO.
38 years of cycletouring, 33 years of running cycling holidays, 8 years of running a campsite for cyclists - there's a pattern here...
pete75
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by pete75 »

bretonbikes wrote:Personally I just carry a battery pack. One like this - http://www.amazon.co.uk/RAVPower-20100m ... s=ravpower - will power lights, gps, phone. mp3 (though hopefully they are all the same) for a good fortnight and it charges stuff really quickly. You need to be very much in the wilds not to find a power point to charge it every 2 weeks...

In my case I carry one half that size and I've yet to have it run out in a fortnight's use but then I'm probably not a heavy user. They are indestructible, charge really quickly, cheap as chips and replaceable if they get nicked whilst you are charging it in campsite loos.

The point being that you have to carry the expense, complication and drag of a dyno-hub whether you need it or not - they are solving yesterday's problem IMO.


Drag - on a modern dynamo hub?? You have to be very, very unfit to notice any and if you think a dynohub is complex how do you regard the Rohloff on the other end. A dynohub is simplicity itself in comparison. As for expense many of the better quality battery front light seem to cost as much or more than a complete dynamo set up.

Personally I don't think I'd rely on something that may be stolen in the campsite bogs to power lights and navigation devices but each to his own.
'Give me my bike, a bit of sunshine - and a stop-off for a lunchtime pint - and I'm a happy man.' - Reg Baker
pwa
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by pwa »

I've been pondering Brucey's thoughts on Rohloff hubs and his preference for 36 spokes, as opposed to the 32 on the rear wheel of the TX-1000. SJS have a lot to say on this topic, and they say a Rohloff wheel will be stronger than a dished wheel with the same number of spokes. If that is true (and it sounds right to me) a 32 spoke Rohloff wheel should be at least the equal of a dished 36 hole wheel. But yes, if you want stronger again a 36 spoke wheel would give additional reassurance. And that is certainly a bike aimed at reassurance. In theory a 26" rim would be another way of making the wheel stronger.
Brucey
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by Brucey »

well lets put it this way; if Rohloff had always produced a 36h hub for touring, a few MTBers might have asked for a 32h one (just because that is the only drilling some of their rims come in) but I suspect that no-one else would have bothered.

Another way of looking at it is in terms of wheel strength vs rim weight. I estimate that a undished wheel is about as strong as a dished wheel if the rim is ~100g heavier in the latter. If you add four spokes then this is again loosely comparable to having a rim that is ~75g heavier.

Obviously wheels can fail in different ways so this estimate is a loose approximation at best but it might allow some sense to be made of different wheels' suitability for different tasks.

You can see that if this estimate is correct, adding spokes is often a better (more weight-efficient) method of strengthening wheels vs using a heavier rim, which is pretty much what Jobst Brandt said in his seminal book.

In a bid to understand the nature of spoke fatigue (by examining lots of broken wheels) I have trawled the LBSs for scrap wheels in the last few years. One obvious conclusion from what I've seen is that rear wheels fail much more often than fronts (by a factor of three or four). Obviously some of the failures are not associated with the spoking and the wheel strength, but many are.

For many types of cycling the old arrangement of 40h rear/32h front is much more sensible than most alternatives, and similarly if (say) a 32h wheel is strong enough at the back, most (unladen) riders would be OK with a 28h or 24h wheel at the front, (apart from when spokes break).

cheers
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bretonbikes
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Re: VSF FAHRRADMANUFAKTUR - TX-1000 Rohloff. Thoughts please

Post by bretonbikes »

pete75 wrote:
bretonbikes wrote:Personally I just carry a battery pack. One like this - http://www.amazon.co.uk/RAVPower-20100m ... s=ravpower - will power lights, gps, phone. mp3 (though hopefully they are all the same) for a good fortnight and it charges stuff really quickly. You need to be very much in the wilds not to find a power point to charge it every 2 weeks...

In my case I carry one half that size and I've yet to have it run out in a fortnight's use but then I'm probably not a heavy user. They are indestructible, charge really quickly, cheap as chips and replaceable if they get nicked whilst you are charging it in campsite loos.

The point being that you have to carry the expense, complication and drag of a dyno-hub whether you need it or not - they are solving yesterday's problem IMO.


Drag - on a modern dynamo hub?? You have to be very, very unfit to notice any and if you think a dynohub is complex how do you regard the Rohloff on the other end. A dynohub is simplicity itself in comparison. As for expense many of the better quality battery front light seem to cost as much or more than a complete dynamo set up.

Personally I don't think I'd rely on something that may be stolen in the campsite bogs to power lights and navigation devices but each to his own.


If you keep topping up your mobile phone (which does GPS and MP3), which of course is easy with a battery pack, you've generally 2-3 days grace in case of problems - more if you only switch it on when you need it - and you could buy a replacement battery pack in any phone shop. I generally charge the battery by just plugging it in the campsite supply by my tent, in their office, in the bar when I'm having coffee, into anyone's USB port etc etc - the campsite bogs is the worse case scenario (and it's not a high value item for a thief). Modern LED lights and hi-capacity batteries mean the dynamo is just an added complication. For example - you dink a rim in a pothole - you need to find a wheelbuilder (where?) to fix the wheel and probably wait days and you rely on reliability of hub and wiring (the same sadly applies to hub gears for me). They were a great option, and I can see that people investing in them value them highly which is just fine as they are expensive.

As for the German laws on dynamo - I didn't know that and I see one of VSF's bikes (the Simplicity) doesn't use them so I wonder if the law has (sensibly) changed. My own LED lights stay on when I stop the Dynohub ones on the VSF-50s go off leaving you in the dark - personally (again) I think that this should be a more fruitful avenue for lawmakers...

On the other hand if
38 years of cycletouring, 33 years of running cycling holidays, 8 years of running a campsite for cyclists - there's a pattern here...
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