psycholist

The Superstar 120 click hubs are off the list for XC and trials. The hub shown was used for XC only on a Giant Trance (full suspension XC bike) - here's what I found in mine earlier this week when it lost drive after about a year (The last few months it hasn't been used at all though):

What are you fitting it to? Some forks don't need adaptors for 180mm disks, some do...

I was riding trials for over a year in the 90's before I discovered it was a sport at all... I also invented the question mark ...

It's to separate independent pistons, with independent reservoirs as far as I can see. Using some sort of bypass would lead to the bit point of the lever changing while the brake is held on.

One weird feature of imported words is that if the word and its plural are both taken from the source language at the same time then the plural is as in the foreign language (Vertebra/Vertebrae), if not its pluralised as in English (Pendulum/Pendulums). Sometimes though the singular and plural make their way to English through separate routes and have separate meanings like datum and data...

Is the pain just in your back or do you get a shooting pain down your leg occasionally? That often means a slightly slipped disk (The nerves feeding the legs pass between the vertebrae, so a misalignment or damage in the spine can lead to phantom pains elsewhere). The most likely thing to be wrong is the muscles supporting the joint between your pelvis and the bottom vertebra of your back being pulled or torn. The first thing I'd do (Provided the pain isn't too severe - if it is you need to see a physio, doctors will often just tell you to rest it and take anti-inflammatories) is try to build some flexibility into your back. Have a look for stretches for your back on the internet (There are loads - if it hurts, especially sudden sharp pain, don't do it). What you want are stretches you can control very easily such as touching your toes while sitting on the ground with your legs straight, twisting your upper body from side to side from the same position or kneeling on all fours and curving your back up and down. Once you're stretching your back regularly the pain should diminish. Do not bounce or carry momentum into a stretch, just hold it for say 5 seconds first 3 or 4 times and then for longer as the muscles warm up a bit. The next thing to do is deal with the reason it's happened - this is likely to be due to you curving your back forward while pulling the bars back or hopping your bike. Your lower back will not carry loads well while its curved forward, so either try bending your legs more while on the back wheel to keep your lower back straight (Not really straight, a healthy lower back should curve inwards between the hips and the bottom of the rib cage) or fit a longer stem to increase the distance between the bars and pedals. Often once you become conscious of what's causing the problem it will disappear of its own accord, but be warned that your back is pretty important, so long term pain shouldn't be ignored.

Energy and force are not the same thing. I blame the discovery channel for completely screwing up the chances of anyone working out what units are correct to measure things without more research - ever notice how they give force is in tons (Units of mass), pressure is in kg (Another mass unit) and lengths are in double decker buses/height of the Eiffel tower etc. Energy is the ability to do work. Force is the application of a load - it will only do work if the force causes a displacement. Force (Newtons) x Distance Moved (meters) = Work Done (Nm or Joules). Force (N ) x Velocity (m/s) = Power (Nm/s or J/s or Watts). Work and Torque have the same units incidentally - this is not a coincidence...

Weirdly SRAM - which I and pretty much everyone AFAIK pronounce as a word even though it's always written in all capitals is Mars backwards - coincidence or just weird?

If you want a serious buzz from the hub try industry nine and Superstar rear hubs - 120 engagement points compared to the King's 72. The i9 might work for trials, wouldn't trust the Superstar for trials at all, but it's sweet on my XC bike, though the freewheel mechanism did need a stripdown and clean after a year...

I use one of these: http://www.chainreactioncycles.com/Models.aspx?ModelID=10223

Also a smaller front sprocket means higher chain tension to transmit the same torque from the cranks - going from an 18T to a 16T front sprocket increases the chain tension for the same pedal load by 12.5%... Going from a 18 to a 22T drops it by 18%. This is why you can get away with 8 or 9 speed chains with a 22T chainring (If you're careful), but on an 18T chainring having the chain snap is nearly certain unless you run a BMX chain unless you never do gaps. Remember that a 10T cog has less than 5 teeth carrying the whole load from the chain, so you'll get plenty of premature chain and sprocket damage compared to say a 15T cog where 7 teeth (40% more) carry the load...

Avoid the Thomson stems that use a wedge which presses on the steerer to hold the stem on. They're complete junk as they not only damage your steerer but don't hold the headset bearings tight either. Other Thompson stems with pinch bolts are fine AFAIK.

I pronounce ENO as it's written - the only brands I don't to that for are those where the initials do not form a pronounceable word, forcing you to list the letters in order to say the name. But then I couldn't be bothered pronouncing the 'e' in Nike to make it rhyme with pikey either...

Here's some competition footage - the bail at 24:10 is the funniest looking trials crash I've seen in ages... http://www.vimeo.com/3994332

Mmmmm Gü...

Here's a bit about the reason for the thread direction choice - http://en.wikipedia.org/wiki/Precession_(mechanical) I have a mechanical engineering final year project where a test rig was designed to measure this on my desk but haven't read it yet ...

That was an out-there guess, but it's the only thing I can think of that would affect the hub as a trials hub. The damage needed for the click to be based on my idea would be very small though, but it should still be visible.

The easiest way to remember how to unscrew both pedals anad BB's is that if the bearings seize and you continue to pedal forwards, the BB and the pedals on both sides all come loose. This is not the reason they're made this way though - it's all down to torque free precession...

Sometimes headset creaks can sound a lot like they're coming from the BB - If you've dismantled everything and reassembled with copper/normal grease and the creak hasn't changed, then none of the surfaces you've greased are responsible. Look for cracks in the frame too... If it's a mod try greasing the bashguard where it touches the frame as well.

Who's the fatty now shetbag ... For the disk with one piston pumping out more than the other try removing the pads and pumping the brake lever while holding the piston that moves out correctly in place to force the other piston out. Then wipe the sides of the piston with brake fluid and push it back in fully. Pump the lever without holding either piston and the pistons should move more evenly. Don't pump the pistons out more than a couple of mm though - too far and they'll come out of the caliper (Followed by the oil in your brake)...

The click sounds like a warning sign - the way kings engage (And based on the evidence of other damaged surfaces inside the hub) it might be notching in the helical part of the mechanism that presses the drive rings together when you put power down. The click may be the movement of the helical section to increase the drive ring engagement. If this is the case if the notch gets worse it may stop engaging powerfully over time - I'm guessing this based on one of the previous posts saying the click disappeared once he stretched the spring, stopping the hub hanging up on the notch after freewheeling, going straight to the fully engaged position thanks to the spring pushing harder.

In many cases you're splitting hairs with brake choice. Well set up, any of the systems you're looking at will work perfectly and won't hold you back. If you find certain behaviours of the brakes you've chosen aren't to your liking then see about changing, there's nothing wrong with what you've chosen .

Car brake and clutch cleaners aren't suitable for bike disk brakes apparently as they leave a residue. They could be useful for rim brake degreasing, but rolling the bike through wet grass is amazingly effective in my experience. If you're dealing with wet conditions a grind is probably a better solution, but I've not used tar/brake spray and haven't heard enough good about it to consider trying - most of them stop working when it's damp, which in a cold temperate maritime climate is pretty much every second day...

We'll see how quickly the ones I ordered tonight make it to Ireland too - I've a few mm of pad left on the current setup, it's pissing rain outside and I've ridden every night since Tuesday till 2 or 3am and I'm feeling it now, so I'm in no rush ...

I'm pretty sure it'll lock up if the brake is powerful enough to lock up, same as any other brake. With a bit of practice controlling the brakes independently it's pretty easy with this sort of arrangement. I'm basing this on being able to easily change gear (Timing it correctly with easing off on pedalling) while still controlling my braking force precisely on the dual control shifters on my XC bike. Pushing the lever down to change gear while braking is pretty easy and the movements can be controlled quite independently too - not so easy for gear shifts the other way, but I can do that too (And it's irrelevant for this thread)...