Author Topic: Dreaming and thinking  (Read 8059 times)

No

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Dreaming and thinking
« on: July 22, 2013, 12:58:41 AM »
First off, I hate QR's. I've always found it strange that all that weight is supported by those 4 little nubs on a bike. I much prefer the concept of through axles. And now that Schmidt makes a through axle front hub, I've decided that's what I want on my next bike. I especially like that I don't have to worry as much about the disk brake making my QR loose as there is no QR. If Rohloff made a through axle hub I'd certainly use it, but I'll probably just end up with the bolt on, if this ever happens, with a pitlock lock on it.

The next thing is rim brakes. I want disk brakes because I don't want my rims wearing and I don't want to worry about blown tubes and I don't want to have poor stopping power in the rain and mud.

So this brings me to the problem. Cold weather. Will disk brakes work and not be damaged when it's below 0 degrees Fahrenheit? Should I go with mineral oil or DOT fluid? And because there are no steel forks that Thorn makes for 15mm axles and disk brakes I would likely end up with a suspension fork, which I kind of hate thanks to the promise of increased maintenance, but my hands would certainly like it, but will a suspension fork's seals handle cold temps? And should I go air or spring with one?

This would be for a Thorn Nomad to be used for exploration and as a utility bike.

JimK

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Re: Dreaming and thinking
« Reply #1 on: July 22, 2013, 02:30:27 AM »
I can't help you with the specifics of your puzzle. But it just gets me thinking about chains of logic and where they can drive a person. A particular type of axle drives one to suspension forks!

An STI brifter on my Trek 520 failed.... I ended up with a Thorn Nomad! I know about these chains of logic!

Andre Jute

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Re: Dreaming and thinking
« Reply #2 on: July 22, 2013, 02:46:03 AM »
Yo, No.

General information. You might want to ask which versions Thorn offers, and which fit the Thorn frames. Rohloff makes a fixed-axle version of their hub gearbox; look for the TS models. In addition, you can use the CC model and replace the quick release with a nutted version of the shaft, including security nuts. I have the CC model with a shaft that one side has just a gripless pyramid button and the other side an Allen nut which could be replaced with a security nut. It looks very tidy. You can't mix and match the models, though, as they are built from the axle outwards.

A rim is just a large disc -- thus bicycle rim brakes are also disc brakes. If you need hydraulics, use the Magura HS hydraulic rim brakes. I have the Magura hydraulic rim brakes and love them. On an expedition bike you will in any event choose thicker-wall rims, so the wear rate will be much lower than you fear. The problem with disc brakes is that they wear out pads at a substantial rate, so there is considerable maintenance to keep the pads fresh. There's a reason most world tourers don't use disk brakes. The Thorn fork is just about the most beautiful part of the entire bike; be a shame to give it up for the wrong reason.

If you want or need suspension, have you considered that 50 or 55mm low pressure tyres (balloons) give you 95% of the advantages of mechanical suspension without the cost and the maintenance? Use the search box and search for balloons, Big Apple, Schwalbe. There's quite a bit on this board about suspension by informed tyre choice.

Andre Jute

triaesthete

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Re: Dreaming and thinking
« Reply #3 on: July 22, 2013, 08:29:51 AM »
Oh No!

I'm surprised you are even looking at Thorns on this basis. They major on proven, rugged simplicity. Unfortunately it is in almost no one elses  interest to market things in this niche...and I suppose that's why there is some philosophical convergence amongst forum members. Different chains of logic if you like. Complexity is the enemy of utility.

The main technical purpose of through axles is to provide additional rigidity, via increased diameter, at the working end of suspension assemblies. Thorn steel forks are already rigid enough at the bottom so they would be overkill.

If you had no disc brake there would be no worry about axle security, or leaks, or short pad life, or partial seizure,  or bent rotors or heightened theft appeal. Hydraulic fluid type would be largely dictated by the seal compatibility of the system you choose to use.

Rim wear issues can be addressed with carbide rims (Rigida Grizzly or Andra with CSS finish). Very low maintenance and adjustment requirements with V brakes. Blown tubes? use the brakes alternately on long descents to allow rim cooling. You'd have to do this with discs as well to avoid heat induced fade, unless you fitted really large vented rotors...

And worry ye not about the "little nubs". The axle supports the weight and the nubs just provide the clamping force and are as big as they need to be.

Air forks: seals leak: fork collapses to minimum travel. Not a get you home thing like a steel spring fork that may just leak all over the brake.

Fit fat tyres instead like Andre suggests, and run about 30psi or lower off road.

Go simple, have fun more of the time and leave the extremes to the marketing people :-)

Ian






No

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Re: Dreaming and thinking
« Reply #4 on: July 22, 2013, 09:58:55 PM »
Oh No!

I'm surprised you are even looking at Thorns on this basis. They major on proven, rugged simplicity. Unfortunately it is in almost no one elses  interest to market things in this niche...and I suppose that's why there is some philosophical convergence amongst forum members. Different chains of logic if you like. Complexity is the enemy of utility.

The main technical purpose of through axles is to provide additional rigidity, via increased diameter, at the working end of suspension assemblies. Thorn steel forks are already rigid enough at the bottom so they would be overkill.

If you had no disc brake there would be no worry about axle security, or leaks, or short pad life, or partial seizure,  or bent rotors or heightened theft appeal. Hydraulic fluid type would be largely dictated by the seal compatibility of the system you choose to use.

Rim wear issues can be addressed with carbide rims (Rigida Grizzly or Andra with CSS finish). Very low maintenance and adjustment requirements with V brakes. Blown tubes? use the brakes alternately on long descents to allow rim cooling. You'd have to do this with discs as well to avoid heat induced fade, unless you fitted really large vented rotors...

And worry ye not about the "little nubs". The axle supports the weight and the nubs just provide the clamping force and are as big as they need to be.

Air forks: seals leak: fork collapses to minimum travel. Not a get you home thing like a steel spring fork that may just leak all over the brake.

Fit fat tyres instead like Andre suggests, and run about 30psi or lower off road.

Go simple, have fun more of the time and leave the extremes to the marketing people :-)

Ian







Have they solved the problem with carbide rims not working well in wet weather? Are there pads that negate that effect?

julk

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Re: Dreaming and thinking
« Reply #5 on: July 22, 2013, 10:58:30 PM »
No,
I have a Thorn Rohloff tourer with CSS rims and XTR V brakes.

I have moved from the blue Swiss Stop to black Kool Stop, both say they are designed for CSS.

My experience was that I found the blue ones incredibly good in the dry and very poor in the very wet.
I find the black ones give a more even performance and yes I can now stop in the very wet, they are lasting well.
Julian.

triaesthete

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Re: Dreaming and thinking
« Reply #6 on: July 23, 2013, 12:18:09 AM »
Hi No

All component choices involve a compromise of some sort and there is no perfect brake out there. However css rims and blue pads are the best solution I've found so far.....if black Kool stops work even better I'll be truly overjoyed.

I find they stop as well as anything else in the dry and need a much harder squeeze in the wet to clear the water and then they have pretty much normal power and modulation. So I wouldn't ride wet criteriums or a really manic commute on them, but in any other use it is a characteristic I can adapt to. (BTW where I ride its is VERY hilly, it rains a lot and I do the bulk of my mileage in the dark).

Huge plus points on the utility side though:
Unbelievably long adjustment intervals due to really low pad wear rate. (Way better than discs or regular rim brakes in my experience).
Work adequately or better in at least 95% of my riding (on and off road).
Much cleaner than regular rim brakes in the wet. NO black slop  ;D
Rugged lightweight low tech simplicity,reliability and cheap components.
Work equally well with flat or drop bars.
No fancy tools and no mess servicing.
Nothing to leak or deteriorate over time.

I think wet performance would be improve  a pad redesign so that the leading edge acted as a scraper  instead of an aquaplane. I live in hope.  edit: Just looked at the kool stops and that's exactly what they've done.

I hope this is useful
Ian
« Last Edit: July 23, 2013, 12:36:21 AM by triaesthete »

Andre Jute

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Re: Dreaming and thinking
« Reply #7 on: July 23, 2013, 01:56:10 AM »
I hope this is useful

At the very least it is fascinating. "No black slop"!

Is there anyone here who has actually worn out a touring rim -- as distinct from a lightweight, thin wall racing rim -- by wearing through the brake surface? I take No's point. If that will happen every year or two, I might put up with the expense and the time required by disc brakes, and the constant attention you have to apply every time you apply them. I like riding my hills very fast and braking hard but with almost automatic modulation, without that on/off feeling of discs. But if it is only every third or fourth or nth year, nah, I'd rather have my faithful old Magura HS11 -- the older, less powerful style, eminently suited to not face-planting an absentminded intellectual when he slams them on; they're truly fit and forget brakes. Of course, the opinions of off-roaders will differ.

Andre Jute

No

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Re: Dreaming and thinking
« Reply #8 on: July 23, 2013, 05:11:56 AM »
About those Magura's, how well do they work in the cold? And how reliable are they? What kind of clearance do they have? And do they really provide more stopping power even with css rims?

And what sort of pads should be used with them? Magura brand? I see they have some for ceramic rims, I guess that applies to carbide rims too?
« Last Edit: July 23, 2013, 05:18:11 AM by No »

triaesthete

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Re: Dreaming and thinking
« Reply #9 on: July 23, 2013, 07:24:19 AM »

Andre
would your Maguras be the spiritual equivalent of my Schmidt hub?

I love Deore!

Ian

Andre Jute

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Re: Dreaming and thinking
« Reply #10 on: July 23, 2013, 07:38:03 AM »
About those Magura's, how well do they work in the cold? And how reliable are they? What kind of clearance do they have? And do they really provide more stopping power even with css rims?

And what sort of pads should be used with them? Magura brand? I see they have some for ceramic rims, I guess that applies to carbide rims too?

The Magure rim brakes are hydraulic; they work as well as disc brakc hydraulics in the cold. I've only ridden in really low temperatures a few times, in sub-zero probably only a handful of times, and never noticed any degradation in performance. Nor have I heard of any problems.

Magure hydraulic rim brakes are the most reliable brakes there are. They come as a closed, fully assembled, no bleed system and require no service, ever. They are truly fit and forget. Mine have done about 6500km on the same set of blocks, hardly worn. I wasted the money I spent laying in three sets of spare blocks, besides the spare set the builders of my bike included in the welcome pack, when I bought the bike five years ago. (I ride out in the country mostly. I don't brake all the time, but when I do brake at junctions, I usually brake hard.) I've adjusted the blocks once, when I fitted a rim of a different width; I've never adjusted them for wear; they're essentially self-adjusting.

You run Magura brake blocks at the same 2mm or so spacing as any other rim block.

It may be possible that Maguras could provide more grip on CSS rims than mechanical systems. but I think, just on general principles, that it would be marginal. It's the CSS rims that are the problem, not the gripping power in any kind of good bicycle brake available today. The point of the Maguras is that they work under all conditions, and they work the same every time, very consistently, and they are very progressive, which you can't say for disc brakes.

There are several kinds of colour coded Magura blocks available, and aftermarket blocks as well, that some swear by for greater stopping power at the cost of longevity. A few years ago I followed a thread on a technical conference and the experience there was that the common black block gave the most stopping power with the CSS rims though it wore faster than the grey or  the green or whatever the special CSS block was. It was still a longlived block though, by any standards.

***

If you really want a brake that works under all conditions and keeps working without any clearance worries in icy and snowy conditions, you should consider Shimano's roller brake at the front; there is unfortunately not a version for the Rohloff. You'd have the same problem, that Thorn won't put disc tabs on a steel fork, and the roller brake has a torque arm that bolts to disc tabs. But on the other hand, it is a fully enclosed brake, it is extremely powerful, its service consists of squeezing in special grease from a clean-handling tube at long intervals through a small port. I've had the limp IM-40 series, long obsolete, and on a bike for the Euro-elite http://coolmainpress.com/BICYCLINGsmover.html I had the very powerful IM75 series roller brakes (check out those cooling fins -- it needs them!), which killed the Magura Louise discs I had on another similar bike at the same time -- and the Magura Louise were then as now said by their fans, of whom I was one too, to be the best disc brakes (a lot of) money could buy. My not so humble opinion: The best modern roller brakes are an overlooked sporting proposition, unfairly relegated to city bike use.

On the downside, the IM75, and possibly all powerful roller brakes, are damned sudden if you ride them on the edge; if you don't want a face-plant, you better pay attention to how you handle that lever; they're like discs set up with miniscule tolerances and the booster  turned up. I found the Magura rim hydraulics, of which my bike maker especially chose the weakest one (largest chamber, lowest pressure) to suit my careless riding style, a relief after the demands of the IM75 rollers.

Andre Jute

Andre Jute

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Re: Dreaming and thinking
« Reply #11 on: July 23, 2013, 07:57:36 AM »
Andre
would your Maguras be the spiritual equivalent of my Schmidt hub?

I love Deore!

Ian

And a security blanket besides!

It occurs to me that I may have left people with the idea the Magura rim hydraulics are limp: they're not. I had a demonstration of their power less than hour ago. I went out before dawn to beat the forecast rain and heat, found I was going better than in a long time, and extended the ride onto roads I don't normally ride because they're dangerous for cyclists. Looking at some interesting clouds, wondering if I had time to stop and paint them and still beat the rain home, I missed a Black Spot sign and suddenly came on this T-junction onto a lethal road with the early morning trucks and cars thundering along it, and they too having zero visibilty on me and almost zero reaction time. I slammed on the anchors so hard I actually flatspotted the rear tire just before it lifted, and pulled up to a right sudden stop. On any other brake that could have been a face-plant, but the Magura take-up, even in an emergency, was still smooth enough to save me the embarrassment, the pain, and the danger, because just then two co-op trucks screeched to a halt behind me, the drivers hardly having time to see me because of the topology. It's a pity that the current HS11 shares the architecture of the HS33 (small chamber in both, same pressure, only difference is in lever construction, the rest is cosmetic) because there is quite a bit to be said for the more accommodating version I have.

Unless you have CSS rims, of course, then you'd better have the modern version, and the stiffer lever of the HS33 might give you that bit extra in an emergency.

Me too: I'm a big fan of Shimano in general and Deore in particular. There are many components that are at such a stage of development, they're just about generics. In those cases, and in many others, anyone who pays more than the Deore part costs is a wastrel. But try to explain that to any cyclist who isn't a Scot.

Andre Jute

julk

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Re: Dreaming and thinking
« Reply #12 on: July 23, 2013, 11:49:24 AM »
Andre,
Yes, I did once wear out a good quality touring rim on an XT equipped Dawes.
I used to commute to/from work in Edinburgh, 100 miles a week, riding in the potholes and debris left by cars and buses etc.

The front rim eventually wore through by the abrasive effect of the braking especially with the grit picked up in the rain.
Luckily I noticed it as it started to peel away and managed to avoid a face plant.

I have been using CSS rims for 3 years now and there is no visible wear.
Julian.

triaesthete

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Re: Dreaming and thinking
« Reply #13 on: July 23, 2013, 05:55:40 PM »
I was just being cheeky Andre. Prodding the intellectual bear  :)

A lot of people I know around here have had worn thin rims fail.The tyre blows off taking a good part of the braking surface with it. Like this http://www.bikenorth.org.au/archives/chainmail/201011/11.php

Lots of rain and sandstone geology!

Ian

Andre Jute

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Re: Dreaming and thinking
« Reply #14 on: July 23, 2013, 09:51:10 PM »

Julian, Ian: Good heavens above! You'll have to excuse me. I'm off with my calipers to measure my rim walls. -- Andre