nomad with roholf

[stever1]

re nomad i also think this would be ideal
now 2 other things that i would like to enquire about

disc brakes im thinking shimano mechanical discs
are these repairable ie spare cables when i venture abroad ??

also wheels my thorn tandem has sun rhynos which have performed brilliantly.

do i need such heavy rims has anyone tried the sun rhyno lites


  []

[stutho]

I am a little shocked that the new Nomad has a disc brake option. The old model didn't and it is out of keeping with the rest of the Thorn touring range.  In the past Thorn have said that there is more to go wrong on a disc brake (most notably a warped rotor).  There may also be a problem with certain calliper/ rack / pannier combinations.  The only tour bike with a disc option was the exxp. The exxp was also specifically designed for shock forks so maybe that is the commonality.  Even The catalyst mountain / touring bike (and only other touring bike designed for shocks) does not have disk mounts!

[stutho]

Stever1 Regarding wheels:

I use Mavic 717 rims - I have fitted them to 2 of my 3 bikes.  They are quality rims designed for cross-country mounting biking racing and are therefor reasonably strong but also light.   On one bike I have the ceramic finish – a luxury.  I have used them in all sorts of conditions including some mounting biking I have never had any problems with them.  For 'normal' touring  (on road) I would recommend them.  Having said that if I was intending to tour in remote areas I would go for a heavy weigh rim the same would be true if I new that I would be spend weeks (not days) on unmade up roads.  

[bike_the_planet]

quote:Originally posted by stutho

I am a little shocked that the new Nomad has a disc brake option. The old model didn't and it is out of keeping with the rest of the Thorn touring range.  In the past Thorn have said that there is more to go wrong on a disc brake (most notably a warped rotor).  There may also be a problem with certain calliper/ rack / pannier combinations.  The only tour bike with a disc option was the exxp. The exxp was also specifically designed for shock forks so maybe that is the commonality.  Even The catalyst mountain / touring bike (and only other touring bike designed for shocks) does not have disk mounts!

Have you considered that, in a few years time, obtaining 26" rims that are rim brake, rather than dic brake specific, maybe more difficult? A quick glance at a bike down here (Perth, Australia) and the only bikes fitted with 26" rims are MTBs - and all MTBs (cross-country or downhill) now come with disc brakes.

I reckon that in 2 - 3 years time it will be almost impossible to get a rim-brake 26" rim. Shame - I have a 2000 Nomad with S&S couplers - great heavy touring bike.

Cheers

[stutho]

quote:Have you considered that, in a few years time, obtaining 26" rims that are rim brake, rather than disc brake specific, maybe more difficult?

A disturbing argument. I have to admit that maybe 50% of the MTB sold this Christmas will be disc equipped.  Funny thing is that most of these bikes (especially the cheap kind) would of being better equipped with rim brakes.  We may all become the victims of fashion.  


I can't imaging that there will be NO 26" rim-brake rims.  BUT you may be right that it will gets more difficult to obtain such rim.  I could also hypothesise all such rims being ceramic coated and therefor far more expensive than currently available.

As we are just speculating I would STILL recommend that for a touring bike rim brakes offer far more advantages and are therefor the way to go.

[AndrewClark]

"Have you considered that, in a few years time, obtaining 26" rims that are rim brake, rather than dic brake specific, maybe more difficult?"

Indeed this could be a worry. All high end MTB's come with disks as standard, so do the low end ones!  However you can still buy Cantilever brakes & blocks in the UK and if the marketing men had had their way they'd have been well obsolete. Due to a demand from consumers Shimano now have a new design available and there are several "boutique" models at boutique prices.

I think we'll have suitable wheels for a few years yet.

A future proof bike though should have both disk and canti mounts. Just in case... touring somewhere remote and damage your rotor or have a line cut - buy (or scavenge from the dump) a set of cantis and bolt them on.

Someone recently tried to sell Thorn Raven frames on Ebay with a brazed on derailleur mount. Not such a
bad idea, if your rim & spokes were badly damaged or the entire rear wheel stolen you could source a cheap rear wheel and derailleur and carry on. Need something to keep the cable in tension though.

[bike_the_planet]

quote:Originally posted by john28july

Hell,
Down under 26" braked surface rims becoming obsolete?
I think you must just be having a laugh! I know the Crickets good for you at the moment, but no 26" rims in the future? Surely not.
John.

Cricket good???...at the moment??? It's ALWAYS good for us down here, mate []

Seriously, I don't think for a minute that rim-brake rims will disappear overnight, but I think that they will become more difficult to source as time goes on.

The cycle market down here is just a microcosm of the rest of the world and may not be representative of trends elsewhere, but 99% of MTBs (both downhill and XC) sold here are fitted with disc brakes. Is the UK different in this respect?

If the above is the case worldwide, then ask yourself this: why would rim manufacturers continue churning out big production runs of brake-surfaced rims that 99% of the market no longer requires. It wouldn't make economic sense.

I'm sure that there will be planty around for the next couple of years as present stocks are used. But what then?

Please give me a good argument as to why not - after all I have invested in both an xTc and a Nomad!!!

Cheers

[goosander]

I don't think 26" rims with a braking surface will disappear anytime soon but I do think that the choice of rims is likely to reduce and in 10 years time there may only be a couple of decent rims available.

Although most mountain bikes have disk brakes (if you ever done any offroad, you'll know why) there are still loads of 26" wheeled urban bikes that still use rim brakes and will probably continue to do so, since that type of bike is more about functionality and price, and decent disc brakes are quite expensive.

[bike_the_planet]

[/quote]
Hello,
Microcosm of the World eh? You live in my lifelong dream Country. Enjoy your life you have it made Down Under.
The rims I have on all my bikes are braked type. Regarding the percentage of bikes in UK with Disc brakes, search me! I do not, never have and hopefully will never own....a MTB! But looking around the small town I live, I noticed about a 50/50 Ratio and most if not all those with Discs were crap bikes.
The World has millions of bikes. The World needs more. The population of the World in general only knows of rim brakes. Its only so called techies and enthusiasts who know about Discs?
Good enough argument..........

Have a good day.
John.
www.pbase.com/john28july
[/quote]

Hello John - I'm actually a POM - originally from Gloucestershire - but have been in Oz 15 years - yes it is a dream country.

I agree that the world needs more bikes and, BTW, I have never used discs before; I would prefer to stick with rim brakes for touring. However, the bicycle industry tends to go with mass production. In the next few years disc brake manufacture will be so large and the price will come down meaning that more and more of the cheaper bikes will come with discs. So the vast majority of quality rim manufacture will be disc-based.

Sure, 50% of 26" wheel bikes on the road are still vee brake, but virtually all the new ones are disc-braked.

I don't want to see rim brake rims disappear any more than you. But it will happen; the laws of mass production, and industry's relentless pursuit of more technologically complex solutions means it will be so.

Tourists are but a small % of the cycling market. Yer average 'occasional' cyclist is blown away by the efficiency of discs - they're not interested in the fact that you can't easily fix them by the side of the road; that rotors get bent and discs warp; that pads are expensive. They just think they're cool.

It will happen whether we like it or not.

'Aveagooday

[Arnaud]

As long as there will be people like us buying the stuff, someone will keep making it...at a price.
Thorn bikes, Rohloff Speedhub, Leica and Voigtlander cameras,etc...

[stutho]

I wonder if the new Nomad uses the same 725 tubing as the old Nomad?  All the other Ravens use 853. (With the exception of the tour and the tandems which use 969.)

[efpw]

What is the significance of the tubing designation?  Is it related to gauge?  If so, which is the lighter tubing between the 725 and 853?

Questions, questions

[bike_the_planet]

quote:Originally posted by efpw

What is the significance of the tubing designation?  Is it related to gauge?  If so, which is the lighter tubing between the 725 and 853?
Questions, questions

Thorn's '969' designation does refer to their double-butted tube gauge, I believe. They use 4130 CroMo blanks and get their own custom tubes drawn to a thickness of 0.9-0.6-0.9mm.

Reynolds number designation is based on material compostion of the steel alloy, but I haven't got the exact details to hand. Composition is only half the story anyway, because heat treatment of the steel also adds to its UTS (Ultimate tesnsile strength), particularly in the case of 853.

Asking which tube is lighter is a little misleading. All steels weigh the same, in that they all have a density of 7.8 gm/cc. However, stronger steels such as 853 can be drawn with thinner walls because of their higher strength. So 853 is available in gauges as thin as 0.8-0.5-0.8.

The point is this: if you have two tubes of the same gauge - one made of 853 and one of 725 they will weigh exactly the same. 853 has a 20% greater UTS than 725 and is harder as well. This means that you could have slightly thinner walls to make it lighter and it's extra hardness will give it more dent resistance also.

Hope this explains,

Cheers

[stutho]

efpw you may want to look at this chart
Basically 853 can take more load than 725 before it will snap  (I think! - I am not a materials engineer) 725 is not on the chart but it has an Ultimate Tensile Strength of about 1180MPa. (969 is Thorns own tubes)  

The important thing to remember is that the materiel strength is only one part of a very large formula to what make a good bike.  

[efpw]

Thanks for the comprehensive answers.  I understand now..

..at least, I think I do.

Ellis