psycholist

I'm currently running a Supperleggera on the back of my Giant Trance and it's phenomenally good. Instant pickup (Very slightly quicker than a King as the King has a little less backlash, but also less engagement points). The hub feels really solid and the bearings are extremely smooth and totally play free. I've only put a few hundred miles on it so far, but it's giving every indication of being a brilliant XC hub. If it runs for the next year or two and the ratchet pawls remain deformation free, I'll consider trying it on the trials bike. It's also pleasingly loud - like being chased by beeeees...

I got a litre of LHM (Citroen suspension fluid), which smells the same as Magura mineral oil, but is a slightly different colour for a little over 5 Euro... Monty only are competing on price with Magura, who also rip their customers off on brake fluid prices. I'd be interested to try a Magura on standard mineral oil, Monty oil and water side by side. Water shows a noticeably quicker lever return than Magura oil anyway. I'd guess the Monty stuff is probably more like all other mineral oils than like water - unless it actually is water and they're really taking the piss...

Since the HS33 lever has no reservoir, as the disk heats the fluid and it expands the disk will tend to lock on unless you keep winding the TPA out. Then once the fluid cools you'll have to wind it back in before the brake will bite. I'm pretty sure the Louise uses slightly different brake line as it's designed to run higher fluid pressures. The Julie has a similar lever piston diameter and brake line to the HS33, but it will still have the same issues with pump up as the brake heats...

Kool stops or black pads on a grind will be pretty silent, offer some hold (Not really enough for gap to front moves I reckon though) and offer modulation for stoppies and normal (slowing you on hills) type use. Disks are better though...

Sounds like there's air being pumped into the system from the reservoir as you pull the lever. Are you leaving an air bubble in the reservoir after replacing the reservoir cap?

Helium has a weight, but it weighs less than air (1 mol of Helium weighs 2g, while a mol of air is a little under 29g - 1 mol of any gas will occupy the same volume (22.4 litres IIRC) at a given temperature and pressure). It's the difference in mass per unit volume (density) that makes a lighter than air gas buoyant in air. There's no such thing (In current technology) as negative mass, AFAIK even physics antiparticles still have positive mass, dark matter definitely has positive mass. Look up anti-gravity on wikipedia for a discussion on what negative weight might constitute, but they're pretty pessimistic on it's potential to exist too based on relativity theory saying that gravity is caused by the curvature of space. There are certain areas in Canada where gravity is below average - move there or to the equator (Where the spin of the earth is trying to fling you off more than at these latitudes and you're further from the centre of the earth thanks to the oblate spheroid shape of the planet) to improve your hopping height ...

If there's still air in the lever try pumping the lever slowly while pumping fluid through the brake - some levers have dead volume in them that isn't always filled by a normal bleed (The new HS33 levers are serious offenders on this one). Just be careful of brake fluid squirting out of the reservoir as you release the lever. Mineral oil is very safe, but I still wouldn't squirt it in my eyes...

From what I've seen with trials disks they seem to actually need to get a bit of dirt on them every so often to stay working correctly. I'm running an ORO K18 on my bike and the bite was pretty good even from new, but after a day or two the brake stopped holding properly. I rubbed some dirt on the disk, dragged it a bit and it came back to full power immediately. Looks like trials keeps the disks too clean for them to stay working ...

The bleed nipple is on the brake caliper probably near where the brake line leaves the caliper for the lever. It'll probably have a rubber cap covering it which you pop off to get at the nipple itself. The tubing from the syringe should be a press fit over the bleed nipple so you can pump fluid into the brake.

Looks class - way better than the pallets in my back garden anyway . Was it difficult to get permission? Any idea of the cost?

You could argue that couch potatoes take a whole different set of risks though ... Thankfully I've never had to gather data from a obscure group of people, but I know people who have had to do it for their research work, but I have a reasonable understanding of the underlying principles. I'm hosting a guy's thesis on XC mtbing on my web space (Based on another online survey) if anyone's looking for a long but interesting read ... http://www.skynet.ie/~ceason/MTB_Thesis/Mi...issertation.pdf

Bleed the system from bottom to top. Take the reservoir cover off - I think you need a T10 or T15 Torx bit for this, but a 1.5mm allen key will work too. Fit a syringe of oil to the bleed nipple at the caliper (Preferably remove all the air bubbles from the syringe first, same as with rim brakes) and open the bleed nipple with a spanner (Usually 1/4 to 1/2 turn should do it - if you're pressing the syringe you'll feel it as soon as the bleed nipple is open). Pump fresh fluid through until air bubbles stop appearing in the reservoir (Pump pretty quickly to help entrain bubbles in the flowing oil), close the bleed nipple, remove the syringe and try a few test pulls on the lever to see is it better. Try not to spill oil on the disk/pads (Or remove them before starting) and slap a rag or tissue around the lever to catch the overflowing oil. For the brake to be correctly filled the pistons in the caliper should be pushed back as far as possible into the caliper and there should be no air bubble in the reservoir - roll the diaphragm onto the reservoir, displacing fluid before putting the cap back on.

If Titec handlebars are anything to go by I'd be very slow to use their stems. I snapped a set of hell bent DH bars in abut 6 months of trials use (They gave no warning either), other people I know have had Titec stuff break on them very prematurely too, so the handlebars are the first and last Titec parts that will ever appear on my bikes... The items linked are XC stems, so probably built to an even lower strength than the DH stuff they make... Here's what I'd buy (Within your budget constraints): http://www.chainreactioncycles.com/Models.aspx?ModelID=5525 - though it may only be the 120mm one that has the right clamp size .

Was it advertised here before there was a cash prize? I'd probably have filled it anyway - I've filled enough random online surveys for people, when the subject is obscure... It's a royal pain trying to get a statistically significant sample together for research when you're trying to get that sample from a group that only makes up a small part of the population in the first place.

As I understand it each individual competition will have an entry form and the entry process will be given as part of the detail of the event being advertised - most seem to be pre-entry only. You'll also need a day licence for insurance purposes. If you want to do several competitions then you probably need to get a UCI competition licence (This will cover all Mountain bike events, not just trials AFAIK)... I've only raced XC/Marathon/DH(ish), no trials competitions in Ireland, so I've never done a trials competition, but for UCI competitions this should be about right. I'm surprised you haven't got an answer from someone more informed yet though...

If you want to take a mm or two off, clamp the pad into a vice with what you want cut off flush with the jaws and use a hacksaw - it's hard work cutting brake pads even with a fresh stanley knife...

I've had an ENO since the start of the year and it's been flawless... I opened it up to have a look inside and there's still no evidence of the sort of deformation that I've seen in pretty much every other freewheel I've looked into. The teeth on the outside of the freewheel were totally unmarked when I wiped the oil off them too - the rear sprocket (Same age) showed quite a lot of deformation from the chain... Really good quality steel I reckon. It's got Enduro bearings too, which was a pleasant surprise (Enduro have built a reputation for making bearings for suspension bikes that outlast the OEM items by at least a factor of 2)...

All the stuff I've snapped has been from before I was able to afford really suitable parts. The steel bars were OEM Raleigh, the bars on the trials bike were Titec Hell Bent DH bars (Avoid Titec stuff in general, it's shite for non-road use) and the stem was Amoeba welded (Their CNC stems seem to be indestructible). I'm using Echo bars on my current bike and they seem to be lasting fine. They've had 6 months use at this stage, and I'm somewhere in the region of 90kg and not the smoothest rider in the world (Definitely don't go very big either though). When I was speccing the bike last December, I phoned Tarty about the build I wanted and I was told they've never got a set of those bars back broken yet ...

Filled it out, very tedious going ... Not sure if I'm a proper risk taker though... I ride trials as an exercise in precision that happens to be a bit risky rather than a response to a desperate need for adrenaline... Based on the risk of injury you should be chasing basketball players and not trials riders though...

If the headset is worth keeping or already has a pretty low stack height you might have to see about getting a stem with a short clamp length...

Replaceable dropouts would potentially allow you to vary the BB height as well as chainstay length. 26" trials bikes have chainstays that are about as short as they can be without having to cut into the BB shell, while mods usually have slightly shorter than this. An arrangement with vertical dropouts aligned to a disk mount, connected to the frame with a sliding link of some description (There are lots of singlespeed XC frames out there with features like this) would allow for chain tensioning without disk alignment issues. The brake mounts on the seat stays would need some serious thinking of they're to handle 26/24/20" wheels though - the danger is it would end up a bit heavy compared to a single purpose frame. Using an eccentric BB to adjust BB height and chain tension (Not quite independently) would be pretty cool too...

The set on my commuter bike creaked a little before breaking (Assumed it was just the stem needed greasing) and then one side folded downwards while I was rolling off a speed bump - nasty speed wobble, but I stayed up. Another one on my trials bike snapped while I was pulling up on the bars to bunnyhop onto a wall, realised what was happening just quickly enough to not rip the brake line out, so it didn't cost too much to sort. Snapped a stem while landing nose heavy to keep the back wheel from clipping the steps I was bunnyhopping - ended up landing running with the bike rattling between my legs, still holding the handlebars - it probably looked hilarious... The commuter bike bars were steel and the creaking was the warning they gave, the aluminium parts gave no warning, just snapped (And at a loading far lower than the maximum they'd have seen in previous use as is characteristic of fatigue failure)...

Anything that puts extra bending loads on the brake pads is an inherently bad idea. I won't deny it'll work, or be reasonably safe (Find details from someone who's used it without problems and copy their setup exactly), but when I had the same problem D521 in Echo 4 bolt frame. I looked at doing that, but quickly decided buying a new rim was a safer choice (Less chance of the pads failing - you're depending on screws threaded into plastic to support you landing gaps, which isn't a great confidence booster). For the £5.99 they cost, it's worth trying the red pads first - they're shorter than standard Magura pads (More pressure between the pad and the braking surface) and bite and hold very well. they are extremely loud though. My grind is pretty harsh I reckon and they hold very well, haven't tried those pads on any other grind. I fitted a brake booster to my bike, which quietened them slightly, didn't seem to affect power and left the brake feeling fantastic at the lever...

You could try new brake pads - I'd be very slow to risk doubling the backings, especially if it's a back brake as this is a recipe for very nasty crashes if it fails. I remember someone mentioned Magura mounts being available with more offset than standard, but I think they were 4 bolt rather than Evo mounts. Probably the ideal solution is to get a wider rim, but failing that new brake pads is a much cheaper option. Here's what I use: http://superstar.tibolts.co.uk/index.php?cPath=22_35 - on a harsh grind they get eaten quite quickly (They last around 2 months in the back brake, riding 4 or 5 days a week). The red pads have slightly better hold, while the green ones happen to match my bike better (The black ones are almost certainly the nasty ones that come as standard in Maguras and are not to be trusted for trials)...

Have you tried adjusting the brake pistons closer to the rim where they're clamped to the frame? Sounds like the pads are a bit worn. Running the TPA wound in all the way tends to cause them to break earlier too and loads the guides for the brake pads on the pistons more than with the TPA wound out, so it's better for brake longevity to keep the TPA wound out as far as possible.