Author Topic: Tandem decisions - Rohloffs and is there anything wrong with dérailleur systems?  (Read 13029 times)

marcusjb

  • Full of bon courage.
From Co-Motion on the checklist for having Gates timing belts (loads of info here - http://www.co-motion.com/index.php/information/faqs/the_gates_carbon_drive_timing_belt_system ):

If your tandem meets these criteria, the Gates Carbon Drive may work for you
28.5”/724mm boom tube length (measure from rear bottom bracket to front bottom bracket)
Tandem crankset with 130mm BCD timing crankarms
Same length bottom bracket spindles front and rear
A way to adjust chainline or “beltline” on front and rear cranksets
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!


28.5”/724mm boom tube length (measure from rear bottom bracket to front bottom bracket)


It was from memory after all!  So what I should have said was we want a 24" 'boom tube' not the USAian standard of 28.5".

clarion

  • Tyke
I'd love to have a belt driven hub-geared touring tandem.

*checks savings account*

:'(
Getting there...

marcusjb

  • Full of bon courage.
I'd love to have a belt driven hub-geared touring tandem.

*checks savings account*

:'(

Tell me about it - we're taking the drastic step of getting married to finance this beastie!  ;D
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

Marriage is usually a good opportunity to spend silly money, but rarely a way to save money.
Better spend your savings on a tandem rather than on a wedding banquet ;)

Kim

  • Timelord
    • Fediverse
Wait, you can finance tandems by getting married?  Why didn't anyone tell me?   :facepalm:

marcusjb

  • Full of bon courage.
Wait, you can finance tandems by getting married?  Why didn't anyone tell me?   :facepalm:

I should add - part-finance!

We've worked hard on convincing family and friends that contributions towards a new tandem are much more appropriate than pots, pans and bed linen we don't need.  We think it's a good representation of the union - we've chosen to gloss over the fact that this particular tandem will split in the middle!   ;D
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

I never realized that S&S couplers were invented to make divorce easier  ;D

marcusjb

  • Full of bon courage.
Rather hoping we don't get to test out that 'feature'!
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

JamesBradbury

  • The before-ride picture is even worse
    • James Thinks
We've had a Rohloff Thorn tandem (straight bars) for nearly ten years now. Did our honeymoon (Strasbourg-Saltzberg) on it and this year will have a go at some Audax. We too have joked about the S+S couplings being divorce-friendly.   :D

Regarding the gear range, we find it fine. I can't remember what cog/ring base ratio we went for, but it was a little higher/longer than Thorn suggested (they are kind of the Volvo of bikes, IMO). If we get to a 20% hill with full touring kit then we're walking, but that's rare. We do sometimes spin out in top gear, but we're touring, not racing, so it doesn't make sense to go all out down hills.

If the range is really not enough for you then you can swap the chain and cogs for a one off. I've no idea if this is practical with a belt drive, though. The other (pricey) option is a Schlumpf drive which doubles the number of gears (no doubt with some overlap).

We're not at all bothered about the gap between the gears, but I've been used to riding a hybrid 11-32 8-speed for 14 years. In any case, on a tandem any gear is a compromise between the two riders, so neither of you can expect to be at your "perfect" cadence for much of the time.

AFAIK derailleurs on tandems are the same as on standard road bikes, so I'd expect them to wear out much faster. Unless you have some kind of special harmony that we haven't yet acheived, I'd expect more the the gear changes to be "messy" ones with more load on the chain than ideal. With a Rohloff this can stop you changing, but it won't wear things out. (In practice I tend to momentarily force-slow the pedals as I change). The only true annoyance is a slightly sticky 9th gear - changing up into this sometimes gives what feels like 12th, before it drops back to 9. I can cope with this as I'm aware and it's still a great set up.

Maintenance is lower, I'd say. The oil change takes me less time than a full derailleur chain-cog degrease and clean and I only do it once a year. No reindexing or tweaking, seems to "just work".

One of the best things about the Rohloff on a tandem is surely the changing when stopped. If you stop in a high gear on a solo bike, you just lift the rear wheel and spin one revolution to change down. My wife's light, but I can't lift her and the rear wheel one-handed! Coordinating us both getting off and lifting it is quite a faff - oh, quick the lights have changed!   :facepalm:

What I'm not convinced about is how well it would work on drop bars. I tried out Thorn's Mercury to see and felt that the shifter, being on the tops, was too far from my hands when in the drops, hoods or bottom bit. So I ended up riding in the "wrong" gear a little too often as it was more effort to shift than on brifters. I only had an hour test-ride, but I imagine after all day reaching up to shift it would be quite wearing!

Overall it has some quirks, but on the tandem I wouldn't swap to derailleur whatever you paid me.

marcusjb

  • Full of bon courage.
Currently, and the money is coming together so we'll have to make our mind up fairly soon, we are falling into the dérailleur camp still.

A Rohloff doesn't solve enough issues and creates a bunch of it's own issues it seems to me. 

Maybe for a machine that is just for touring - but equally, a Rohloff breaks out in the middle of nowhere and you're f***ed; a dérailleur system and you can bodge them to do something, you can get any old mech (front or rear) and it will sort of work even if you only have a few gears to play with.

Does slightly concern me having a 10-speed setup (our current one being 9) - but we're not a monster strong team, so as long as we take care of the chain, we'll be fine (we'll probably have the CarbonDrive belt for the timing chain). 

What flipping colour are we going to paint it though? (actually, that decision has been handed over to Cass as she has a better eye for these things).
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

Wowbagger

  • Former Sylph
    • Stuff mostly about weather
I haven't read the entire thread but:

How much more than a set of derailleurs does a Rohloff weigh? Negligible on a touring bike.

How much more than a good groupset does a Rohloff cost? I don't know, but I doubt that it's a great deal... oh look! Rather less than Dura-ace! http://www.merlincycles.com/shimano-dura-ace-9000-groupset-60791.html

How much maintenance does a Rohloff require? Very little. A chain lasts a lot longer than derailleurs for obvious reasons. The oilchange is a once a year job and takes about half an hour. Every few thousand miles you have to replace the rear sprocket - that's been less than once a year for me since I had my solo machine. I think I've done it only once, maybe twice, on the tandem.

How reliable is a Rohloff? Very. I have ridden over 40000 miles on Rohloffs and we have never had to abandon a ride because of one. Before Thorn had sorted out their wheelbuilding procedure we broke three hubs through the spokes pulling through the flange, but we kept riding. For the past 4 years we have had no problem.

Edit: fwiw I'd never go back to derailleurs, either for solo or tandem work. I could never get them to change gear when I wanted and our experience with an admittedly old Claud Butler Majestic tandem, before we bought the Thorn, was brief but turbulent, culminating in me sending the rear derailleur through the back wheel and breaking 6 spokes. I did manage a bodge which allowed us to ride in a gingerly fashion back to the nearest station, but that could easily have been a walk.
The loss of humanity I could live with.

HTFB

  • The Monkey and the Plywood Violin
Marriage is usually a good opportunity to spend silly money, but rarely a way to save money.
Better spend your savings on a tandem rather than on a wedding banquet ;)
A carriage would be much cheaper.
Not especially helpful or mature

AFAIK derailleurs on tandems are the same as on standard road bikes, so I'd expect them to wear out much faster. 

Not really. The rear derailleur, which is the most expensive, and  IMHO, the most troublesome one, works on an un-tensioned bit of chain. This means that
it should not be able to "see" whether it is on a tandem or a solo. I have to admit my reasoning is not valid for the front derailleur.
Anyway, don't think that we are totally sold to derailleurs! Our current tandem have derailleurs, and we are happy with that, but maybein a few years,
the next tandem will have a Rohloff...

What I'm not convinced about is how well it would work on drop bars.

Gilles Berthoud makes a special device for Rohloffs over drop bars:
http://www.gillesberthoud.fr/anglais/gazette/lire.php?identifiant=41&categorie=INFOMATION#ancre41

I don't know what it's worth, I have never tried one.

marcusjb

  • Full of bon courage.
Well, the deal is just about done. And the answer has ended up being a Rohloff with dual belt drives.

Too late to change our mind now, so hopefully we have done it right - clean and easy to maintain and should look pretty awesome!

Blimey that has been an expensive day though.
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

Well, the deal is just about done. And the answer has ended up being a Rohloff with dual belt drives.

Too late to change our mind now, so hopefully we have done it right - clean and easy to maintain and should look pretty awesome!

Blimey that has been an expensive day though.
Looking forward to seeing it on an Audax when it's been built :thumbsup:
DJR (Dave Russell) now retired. Carbon Beone parts bin special retired to turbo trainer, Brompton broken, as was I, Whyte Suffolk dismantled and sold. Now have Mason Definition and Orbea M20i.

marcusjb

  • Full of bon courage.
Thanks! We are excited and look forward to getting it in early June. The Co-Motions feel very spritely and nimble - we didn't ride particularly far as Cass is full of a cold and we were in our civvies, but it all felt very good.

We will start to think about selling our Landescape now - there are a few people I have mentioned it to already, but keep your eye out on the for sale board if anyone is interested in a really nice touring tandem.
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

Euan Uzami

Excellent. I'd becurious to know how you get on with the belt when you've had it a bit. I know thorn are sceptical but may not be based on experience.
I presume it has to have a special sprocket and chainring-does it need any extra width?
Ha it got 2 belts or 1 belt and 1 chain?

zigzag

  • unfuckwithable
good stuff; what kind of belts did you go for - with the middle slot (more secure) or without one (more efficient)?

marcusjb

  • Full of bon courage.
2 belts - CDX (the one with the middle slot).

The shop is generally seeing around 4 times the life of a chain - given that the belts are, roughly, 4 times the cost of a good chain (but remember that replacing your timing chain on a tandem takes more than one chain!) it doesn't really save much money.

We will carry the two spare belts when touring as it is a game over item if we damaged one - each belt weighs less than 100g.

I have gone a full circle - I had always thought if I were buying any bike that had the primary purpose of touring, it would have Rohloff.  But then I got slightly cold feet and started to wonder what was wring with deraillieur systems. I came back to the Rohloff eventually though. It does slightly worry me that it is throwing all your eggs in one basket (one company) - but also deraillieur systems are going the wrong way for longevity and touring. 11 speed is where it is at for shimano and campagnolo - they are interested in selling more stuff to mamils and the touring market is so small that they justdon't pay it much attention (though their 8 speed Claris system is a step in the right direction).

It does make for a very clean looking bike, and, hopefully, a very clean and easy to maintain setup - no oiling of chains to worry about.

We will have a 21" bottom and 109" top gear - we are not the fastest team in the world, so I think that will do us.

The really important thing is that it will be in viola blue, with white lettering (black outlines) with stainless dropouts front and rear.

Just have to wait until tomorrow to get the revised quote (I know roughly how bad it will be, so it won't be too much of a shock) and then empty my bank account into theirs and the job is done.
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

Phil W

A friend is currently cycling round the world. She has a carbon belt drive. Just passed 25,000km and on second belt. It coped with the sand and grit of Africa and seems to be working really well.

marcusjb

  • Full of bon courage.
I like the fact that whilst sand and grit is not good for them, you just squirt your water bottle at the belts and clean them off!

I have become more convinced on them and Rohloff over the past couple of weeks and some discussions with shops and manufacturer.  (Well, convinced enough to drop rather a lot of money on it!).

For our needs, it will be ideal I am sure.
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

Congratulations on the new purchase! Our next tandem will be a lightweight beast, but will have the gates drive replacing the sync chain. Over here they are starting to appear in new utility bikes too, which I think is great.
California Dreaming

meddyg

  • 'You'll have had your tea?'
marcusjb - is there a photo yet ?

marcusjb

  • Full of bon courage.
Still a few weeks away yet!

The welders in Eugene Oregon probably haven't even started on it yet!

We are expecting it by late May, early June.

We need to polish and photograph the current tandem and start to make moves to sell it.  Once we are back from weddings, we will get on with that.

Very exciting though!

Just to give you an idea - like this, but viola blue, polished dropouts front and rear:

Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!