psycholist

Hammering will tend to bend or break things - what you need is loads of torque. Get the longest lever you can find and apply controlled force to it and you can unscrew just about anything and do it safely.

I reckon if you sent trials videos rather than parts back you'd see more benefit. I'd like to have got my hands on the people who first made cranks with a screw on freewheels and make them change to a spline mount before the trials world started making more parts with the same fitting. I started trials on cantis and a 19" frame, people laughed at the very few disks on the market because they were so heavy and expensive (And nobody could afford them to actually try them out)... So I'd have to send everything back . As regards parts I'd love to have had 10 years ago - Hope trials disks, splined BB's, strong handlebars, cranks, forks and stems, affordable hubs with more than 16 engagements and high BB frames would have all been awesome...

The highest profile case of failure from square edges was the De Havilland Comet, the first jet airliner made (And one of the best looking designs in commercial aviation). Thanks to the plane flying higher than other commercial planes of the time causing greater pressure changes, incorrect sealing on the windows and inaccurate stress concentration factor data, cracks formed at the window corners and eventually caused a number of planes to break apart in mid air. http://en.wikipedia.org/wiki/De_Havilland_Comet If you're really worried about it look up formulae for stress concentration factors around holes and compare the round hole and square hole cases, but once you have a smooth radius rather than a sharp corner, the rim is pretty unlikely to fail. Also even if it does it'll probably be as likely to bend or fold on a landing due to reduced stiffness than crack at the corners of the rim holes. There's also every chance the peak stress in the rim is at the spoke hole anyway... I wouldn't do it because I'm just not that bored ...

Since the braking loads are carried by the post in a V Brake and by the widened section of the backing (And not the post hole) in a Magura, making an insert that clicks onto the ball at the end of a Magura slave piston and fits the hole the post goes into could work. The problem is for V users who are more likely to run onto problems with the backing rubbing the tyre thanks to it having wide sections to mount in the forks on Magura slave pistons. This doesn't happen with Maguras because they're pressed linearly into the rim rather than pivoting in like V's.

I've fitted TNN pads into Heatsink backings, but the TNN ones are slightly longer than heatsinks, so it was just a matter of cutting the pad down a little to fit the backing. Not sure how well it would work the other way around. This was for Magura backings though the V ones take the same pads AFAIK.

If this is for a disk brake you might be missing the ball bearing the bleed nipple tightens against to seal the fluid into the caliper. I haven't opened a Hope one yet (It's only a matter of time though, my brand new since January Hope trials disk has already leaked once but it was just the banjo fitting somehow loosening)...

There's a big difference between the feel and sound of the hub skip and the chain skipping. Chris King skips make a bang with a buzzing overlaid, while there's no buzz from a chain skip. The more times it skips while you're riding the more the freewheel parts are likely to be damaged. I'd pull it apart and have a good look inside. It doesn't take that much contamination between the drive rings to stop the hub from engaging.

Give the old pads a wash with the same degreaser you used on the disk and see if they still work. My Hope ones were perfect after the brake leaked DOT fluid onto the disk last week - The banjo fitting got hit, which unscrewed it slightly from the caliper. A not so quick bleed and degrease later it's spot on again...

I tried muc-off on a contaminated disk recently and it was very effective. If water is beading on the disk rather than forming a continuous film then it's got oil on it...

Any handy source for the T6/T7/T8 (Can't remember which) you need for Magura disk reservoir caps? The only sets I've seen that go that small are heading for 30 squid... If a 1.5mm allen key didn't fit the bolts I'd have been caught out a few times ...

His disks and paintwork will be f**kered by the time that gets through airline baggage handling - remove disk rotors and pad between the metal parts (And for that bike cover the chainring so it doesn't cut the bag - not a problem with a trials bike) and you're on to a winner...

Superstar are brilliant with warranty support - I chewed up the internals of one of their 120 EP hubs on my XC bike and they sent me a brand new one as quickly as the post would allow ...

I've used superstar's disk, v brake and magura pads and they're all good. Got some serious brake howl using the ceramic pads in Shimano disks though, sintered/organic are quiet. Shimano organic works better for me than anything else I've tried. There are recurring threads on Bikemagic and Singletrackworld about the pad material unbonding from the backing on Superstar disk pads, leading to complete loss of braking until pumping the lever gets the backing to the disk, but I've never had it happen. I also don't use Superstar disk pads for trials or run them in the front brake on my XC bikes.

As I discovered on my last Echo frame, without a proper polished finish bare aluminium starts to develop strange looking pits and marks over time, so polish and lacquer are needed to keep it looking awesome for years... Either that or try to get it ball burnished like GT frames from back in the day...

I'm not sure you can coat aluminium with nitride, anodising that colour would be feasible though. Nitride is a great finish to keep clean, but it's so much stiffer than the Aluminium it'd probably cause early cracking if it stayed attached to the frame at all...

If it's done right there's no reason it wouldn't work. Lexan or UHMWPE (Or Ultra-high Molecular Weight anything really) would be two plastics I'd look at... Plastic BMX and MTB pedals have been around for ages too (And not just the crappy ones on cheap bikes). Keep in mind that BMX stems are usually a solid block of aluminium, so complete overkill for the loads involved (Given longer stems for MTB's are hollow tubes), so there's room to downgrade the material for that application.

Loose rotor bolts or caliper bolts are obvious thanks to the extra movement they allow the wheel while the brake is on. Sanded the backs of the pads last night - it took all of 30 seconds with a sanding disk I had around. Can't believe how thick the paint on the back of the pads is - no wonder they could move so easily. Brake is already a bit quieter after heading out for an hour on it afterwards...

Excellent... In my best Mr. Burns voice... Keeping the bike silent makes me less guilty about messing about on the bike in urban areas at 2am... I'll pull the lot apart this evening and see how much progress the pistons have made in digging into the back of the pads and see about helping them...

It's a nasty sound alright, a friend of mine actually refused to take my bike out trialsing yesterday while I was in work because the sound freaked him out too much. I'm going to have a look at whether I can make up a bracket from thin Aluminium that fills the space between the brake pads and the sides of the calipers to see if giving the brake pads less forward/backward distance to move will reduce the volume of the clunk - the pistons won't be able to dig a recess in the back of the pads to hold on to if the pads are moving too much anyway. I'm using my brake on the back of a stock bike, so the movement is slightly more noticeable and one of the reasons for going to disk was the irritating noise from Maguras. Still, unless it proves very mechanically unreliable I'll never go back to Maguras or V's again though - epic bite and hold and wet grass/rain no longer make any difference to performance ...

...and Ireland, though over here tapping is probably used more often to mean asking people for something, usually money. As I understand it there's an option between backwheeling and tapping where you touch the front wheel down on the top or the corner of what you're hopping up before continuing the hop to back wheel. This only really works for stuff low enough to back wheel straight on to, but it takes a little less energy and precision. Taps AFAIK are where the front wheel hits the vertical part of the edge of what you're hopping onto... and I definitely can't do them ...

Based on every fork I've owned that bent or snapped (And there must be at least 6 or 7 of them I can think of) failing due to cracks forming in the back of the fork legs or the back of the steerer or bending forward rather than backwards if they didn't crack, I'll stand by what I've said...

I'm glad I stuck with the Louise up front now ... Hopefully it's a learning curve thing, but if you get used to the Saint you won't be able to ride anyone else's bike...

The real question about the diaphragm brake is what happens as the pads wear. Standard brakes allow the resting position of the piston to move towards the disk as the pad wears. This looks like it'll either require a bite point adjustment at the caliper, much thinner brake pads replaced much more often, or a closed hydraulic system (Which will lock itself on as the disk gets hot and the brake fluid expands). Standard brakes have a diaphragm in the lever to seal the oil in but the diaphragm is not a pressure retaining part. At the caliper the pistons are sealed by o-rings fitted to grooves in piston holes in the brake caliper, so there's no diaphragm there (Unless like in some cars you have a rubber bellows that covers the piston to protect the sealing surfaces of the piston from dirt). Presumably what this system uses is a thin walled part on the piston which flexes when the oil pressure in the caliper increases and in flexing pushes the brake pads out - it has potential, but wear adjustment will be difficult as the diaphragm will always try to flex back to its original position when the lever is released. The piston within a piston idea seems a bit strange. Mostly because the laws of hydrostatics say that the biggest area piston will move first (Force = Pressure x Area) and not the small area piston, so there must be more friction or some other modification made to the system to make it behave as described. At the lever end the small diameter piston will be pushed in first for the same reason and again giving exactly the opposite effect to what the article describes the brakes as doing. I like the servo wave SLX brakes I have on my hardtail and haven't noticed them to be very non-linear. The Saints are different beasts though - It may be that the switch between low and high power on my brakes happens at a point that doesn't matter to me cycling them, though since it's a roller moving towards the lever pivot as its pulled there definitely shouldn't be an obvious step anywhere in the power output.

For a sport to get properly popular it needs a lot of parents getting their children into it from an early age. This is what happens with soccer and rugby for example - these sports are also more socially acceptable, so you'll see an average soccer player get way more attention and kudos from society than an exceptional trials rider. If parents don't support getting their children into a sport from an early age, then the sport depends on later converts to it before it can get big - this means that most people are well into their teens before they're getting the hang of the basics of trials. But then again I'm learning to swim properly for the first time now and I'm 30... It's not like I'll be world champion at it, but its nice to learn new things...

And the Superstar Components 120 EP hub isn't good enough for trials based on the one on my XC bike breaking after a year... Great warranty support though and it wasn't the freewheel mechanism that failed, the pawl carrier cracked instead. Chris King or Hope Pro II are the only hubs for which there's a consensus that you won't easily kill them riding trials.