S America Expedition - Thorn Raven?

[andym]

I know nothing about disc brakes but what happens if the discs get bashed enough to bend / misalign them? Does this mean that they are useless and need replacing? If so then they may be the wrong choice for an extended tour in areas where good bike shops are few and far between.

You can bend them straight again. Not ideal, but it's no more complicated than straightening a rim (and no more likely to happen than trashing a rim). And of course it's easy to carry a spare disc if you really go in for belt and braces.

 

[bike_the_planet]

I am seriously considering buying a Thorn Raven Tour for a year of cycling in South America. It seems a lot of money (£2000-ish). Can anyone offer me reassurance, or suggest that I change my mind for some other (cheaper) option?​

Rohloffs are very well engineered and durable gear systems.

Contrary to many opinions, I think they actually work out cheaper in the long run. When you add up the cost of replacing chains and rear cassettes every 3000km (as recommended by Shimano) with derailleurs it soon adds up. And derailleuers steadily deteriorate in performance with time and wear.

However, Rohloffs are not without their quirks. Being hub gears, their effeciency is slightly lower (around 88 - 92%) as opposed to derailleurs (around 92 - 94%).

I had a problem at the end of my tour in Europe last year where gears 1 - 7 suddenly started slipping violently. Had it happened during my tour it would have had a fairly major impact.

Unfortunately, it necessitated a return to Rohloff. However, it has worked fine since, and I appear to be one of the rare 1% that this has happened to.

I ride a derailleur bike very rarely now.

Good luck.

 

[chris667]

Personally, I think they're overpriced and overcomplicated. I grant you they'd be reliable, but most hub gears would be reliable, and about 1/5 of the price!
I think the SRAM I-Motion 9 has most of the advantages, and if I wanted to build that kind of bike, that's what I'd specify. Losing some of the higher gears is well worth saving, what, £700?
And I still think discs for a touring bike are a very poor choice. I've bent discs and been stuck before now.
If you really want reliable, try a Sturmey AW. Lots of them do 30,000 miles with no more than a teaspoon of oil a week, and you can get one secondhand for the price of a couple of pints. After 70-odd years, it's still the most efficient hub gear money can buy.

 

[andym]

There's a guy (simonfbarnes) who posts on singletrackworld who has been through two Rohloffs after riding through rivers. Rohloff's response was that this wasn't the type of mountainbiking it was designed for!

Yep a hub gear with the reliability of a Sturmey Archer and with 9 gears would be well worth going for. The reliability of the Shimano Nexus was really poor (and if any hub gear enthusiasts want to argue: how many old bikes do you see kicking around with Nexus hubs? None). I wouldn't trust the Alfines until they've been around for a while longer. I don't know how reliable the i-motion are.

I think you have to be seriously unlucky to bend a disc (and even more unlucky to do it more than once). I'm trying to imagine how you would do it - fall sideways onto rocks? Anyway they weigh so little it's easy to carry a spare. As I said, it seems no more likely than mashing a rim - and no more difficult to fix (assuming you carry an adjustable spanner).

 

[chris667]

I have bent two disc brakes and been stranded before now. Maybe it was because the bike had 185mm discs, but still.
Compare this to a V brake, where I can do all the adjustments with an allen key.

 

[andym]

I have bent two disc brakes and been stranded before now. Maybe it was because the bike had 185mm discs, but still.
Compare this to a V brake, where I can do all the adjustments with an allen key.

I've seen someone wreck a wheel so badly that the only way to straighten it was to stand on it. He still managed to ride and use his brakes. Couldn't have done that with rim brakes.

A spare (160mm) disc weighs in at 130 grams (compared with 220 for an inner tube).

Rim brakes and disc brakes each have their pros and cons. There are no knock-out arguments one way or the other.

Oh and if you have Avid BB7s you don't even need an Allen key to adjust them.

 

[bike_the_planet]

Personally, I think they're overpriced and overcomplicated. I grant you they'd be reliable, but most hub gears would be reliable, and about 1/5 of the price!
I think the SRAM I-Motion 9 has most of the advantages, and if I wanted to build that kind of bike, that's what I'd specify. Losing some of the higher gears is well worth saving, what, £700?

Look, if a 9 speed hub gear suits you better, then obviously go for a cheaper hub. No point in paying extra is you don't need the range.

But comparing a Rohloff and a SRAM on price alone is a bit unfair. The former has 14 equally spaced gears (giving a 525% range), internal indexing, a claimed weight of 1700g, runs in an oil bath, only requires a simple oil change every 5 - 10 thousand kms, and has an estimated service life of well over 100,1000kms. The latter has a claimed weight of 1900 g, 9 speeds (giving a 340% range), no internal indexing, runs in grease, I believe requires a hub dissassembly for servicing and grease replacement every 12 - 18 months and an unknown service life.

Of course the former is more expensive - what do you expect??!!

Yes there have been instances of problems. I had some. And I think riders are still pushing the envelope finding out just what they can do.

But there's also a growing number of Rohloff useres who are very happy to pay extra for the ruggedness. They seem to be one of the top choices for those going on transcontinental tours.

Horses for courses.