psycholist

Are they like Hermance Pants?

You don't even need to heat the spokes - they'll still see higher stress at the hub flange and the threaded end than they'll see where they're wrapped around each other. Just stress relieve after building and it will be reliable. Working out the spoke length you need will be the really interesting part though...

Yellows on a harsh grind work very well for me. Still pretty slip free even in the wet. They wear a little quicker than I'd like, but I'll live with that for the performance.

You're exactly wrong on that point. Google for thread precession to find out what's actually happening where the pedal thread meets the cranks.

If you fill the bar will ball bearings or marbles you can still push the end plug out regardless of the bend in the bars. Try with a screwdriver or compressor first though.

Water bleeds in disks are a fundamentally bad idea because the heat a disk can run at is much higher than Magura rim brake fluid will ever see, so the possibility of outgasing and boiling if you use water in a disk is pretty much a certainty, even for trials use.

What hub are you planning to weld. If it's the likes of a Hope it's not a runner because the freehub is steel (Or needs to be to take trials loads) and the hub body is Aluminium, so welding won't really work, not to mind the complexity in trying to find enough surface in contact that you can access with a welding torch. If it's a Shimano I think Surly make an after market freehub body that's just a block of metal with a bearing cup in it to replace the freehub, making your hub fixed. I've heard of people welding freehub bodies to make them fixed, but they found that the weld cracked after a while, probably due to too much flex in the hub. If you just want to run a front freewheel and not a fixie just cable tie the rear sprocket to the spokes of the back wheel to load the hub in the drive direction all the time to keep it permanently engaged and you're done. You also don't ruin the hub trying to weld it ...

That's great stuff. It's nice to see good designs rather than ones that merely look good getting prizes ... A book I read recently that should become a standard reference for anyone who designs things for a living is called 'Design of everyday things' by Donald Norman. The first book I've read to explain why most people can use most features on any given car with minimal training, while very few can programme a VCR ...

Return them and get a set that fits. If you have an old cassette drill out the rivets and use the spacers out of that (Which are plastic and therefore lighter and plenty strong enough to do the job). My commuter bike is done this way - I put a big cassette sprocket on the freehub body on each side of the driven one so even with the complete lack of maintenance on the bike and no tensioner the chain still can't come off.

A full Louise lever should fit and work correctly (I'd guess the lever blades are not interchangeable), Julie levers have a bigger piston AFAIK, though I think the most recent version of the Julie uses high pressure hose, so it may now have a compatible piston size. Try asking on the Magura forum at www.magura.de to be certain and also see if you can order the specific parts you want - Magura can be quite good for shipping individual spares not available from shops if you contact them directly.

Even cooler would be investment casting so you could carve what you want in wax, coat in ceramic and melt out the wax before pouring in the molten metal. I'm pretty sure you should be able to find an alloy suitable for both casting and welding... This all depends on the facilities handy though - you're not going to set up a casting workshop from scratch just to make a few bits...

By the time you've welded 6061 it'll be nowhere near the T6 condition anywhere it matters, so no point in buying T6 treated tubes AFAIK. You can get away without heat treating 6000 series aluminium provided you build heavier to begin with. If I was to build in Al I'd choose 6061 if I had no heat treating facilities. From what I've read (Though reliable information is very limited to be honest) 7000 series Aluminiums must be heat treated after welding to be any use. Investigate 2000 series Aluminium too - it's used for a lot of handlebars, so it should have very good toughness. It's possible the reason it's not used in any bike frames I know of is because it can't be welded though. Another possibility for making complex parts like the chainstay yoke and headtube is to sand cast them if you have the facilities are available. You'd have a very custom frame indeed after that.

Spokes do not stretch significantly if at all after they've been used. When I used rim brakes on my XC bike I regularly rebuilt the same hub onto a new rim with the same spokes 3 or 4 times in some cases. Provided you haven't had a couple of spokes from the wheel snap already (An indicator they're probably all near the end of their fatigue life unless it was crash damage) the spokes will be fine. If you're changing hub be sure to stress relieve the wheel after building.

Once you join the chain carefully any of them will do...

If the spoke holes were set so that spokes could be laced from the left hub flange to the holes offset to the right of the rim this would be the case (For lateral loading). The shape of that rim means that you must lace from the left flange to the left offset holes, so the lateral stability of the wheel will be very very poor compared to a rim with no offset. I can also see the spoke tension bending the rim walls into a polygon if the wheel is built half tightly...

Looks very weak to me, especially with the spoke holes offset that far - it had better be light ...

I used to run over 30PSI in my tyres, but about a year ago I started lowering this to make rolling the tyre forwards on uneven natural surfaces easier (Which it did). I'm now down to 22 PSI on a 2.4" rubber queen (Bigger than a 2.5" Minion) and pinch flatted for the first time in the months since I fitted it last night after a very heavy landing onto the corner of a step. The Rubber Queen is a great tyre for bounce because the side walls are very light. The downside is that there's at least one cut in the tyre sidewall after a few months use and the tyre squirms a lot on the back wheel on side slopes compared to a dual ply minion which has no bounce to speak of, but is completely stable on side slopes. With a DH tube it's pretty light as well as very bouncy and pinch flat resistant though . As for bars, that depends on the frame and stem you have. I changed from a lowish Echo stem with flat bars to a trialtech forged stem and 2" risers and my Echo Control was massively improved - about the same on the back wheel, but now I can bunnyhop it...

For a half link chain to work it has to have bends in the side plates to give each link a narrow end and a wide end for the narrow end of the next link to fit in. This means that the side plates of the chain see bending stress as well as tensile stress when the chain is loaded as chain tension tries to straighten the bends in the side plates (That bending is the reason half link chains stretch more under load too). More stress means much quicker fatigue failure at the bends in the side plates. Having a wide and a narrow end on each link also means that the pins holding the links together are not carrying the tension in the chain on the same line of action. This causes a sideways stress on the side plates where the chain pins are press fitted into them, leading to an increased likelihood of small movements between the chain pin and side plates, which brings on quicker failure when the side plates pop off the chain pins than seen in standard chains.

Have you ever ridden an internal geared hub? Even the best of them have crappy pickup (About as good as a Shimano 16 click freehub). The 3 speed Sturmey Archers are significantly worse for pickup, being more like about a 4 click hub.

Get a grinding stone for the dremel - I used a chainsaw sharpening stone for my bike. It allowed me to easily cut the races out of my suspension pivots when the same thing happened. This might allow you to directly pull the race out: http://www.enduroforkseals.com/id197.html - I got this set as I've done quite a few enduro bearing replacements on peoples suspension frames, hubs and BB's. The price isn't so bad when you convert from dollars... The only problem is the gaps in size between certain of the pullers means the particular bearing you have may not fit.

Ride around dragging the brake. Periodically spray water on the disk and rub in some mud if you have it handy...

WD-40 is a water dispersant rather than a lubricant. That would be what the WD stands for, the 40 means it was the 40th forumlation they tried. WD-40 will wash off the rim with water, but will dissolve the tar off before it goes. I'd either regrind the rim or use a wire brush on a power drill if I was looking to clean tar off a rim though.

I had to switch to ISIS after I started snapping XT (UN-72) BB's after about a year's use a few years ago. I've used a ISIS BB's since I bought one second hand with Middleburns in 2005ish and had no axles snap yet. For everything except trials and possibly DH I'd recommend XT square taper for durability as the bearings last for years. If you snap square taper axles you've no choice but to go for a ISIS axle. My Echo BB has been running flawlessly for 1 3/4 years so far... I think the Echo design gets around the requirement for small crappy bearings by using the axle surface as a bearing race, allowing nearly square taper sized bearing to fit.

The guy on the stock is named Darren AFAIK... Last time I was out on a spin with him he folded his phone (Which was in his pocket) over the corner of a bollard in a crash ...

18:15 is pretty popular. One tooth either side of that is common enough. A 13T sprocket with a 16T freewheel is the closest gear to that ratio.