psycholist

The milling machine (With the correct cutter) should be perfect for mitering the tubes. Have you tube bending equipment? If not it's going to be quite hard to get reasonable tyre clearance at the chainstays, but you could go all DeKerf on the seatstay bridge: http://www.dekerf.com/Details.asp?id=13. One trick I'd try for maximum chainstay clearance would be to make the chainstays where they leave the BB from a flat plate. Cut a hole the size of the BB shell in one end and weld it around the BB shell to give maximum weld area as well as sitting the chainstays as far apart as they can be without interfering with the BB fitting - going partially around the BB shell would still give extra weld area. ISCG mounting holes could be put in this type of chainstay without having to add a separate plate too, so useful for non-trials bikes as well... You'd have to cut the chainstay height down after the part around the BB shell to make sure there's room for the chain of course.

Bananas have high levels of potassium, an electrolyte needed by the muscles. Shortage of electrolytes leads to cramping. Most salts help with this as sodium and potassium are common components of salty foods.

Sport is about doing - not watching. If you like to ride BMX then ride BMX. If you prefer trials then do that. Who cares whether it 'looks good' to other people?

I've seen a lot of BB's go wrong by having the bearings get really stiff (Usually the BB develops a bit of play and then the bearings start to move out of line on the races and seize against each other) - if backpedalling and pedalling forward makes the cranks feel a bit freer, the BB bearings are definitely shot. Hitting the BB with a hammer usually will not cause any damage unless you deform the surface you are hitting. It's surprisingly hard to cause pitting in bearings by hammering them... The quick way to check is to take the chain off and see how the cranks, freewheel and rear hub each spin by themselves.

If you're feeling resistance while pedalling, then the BB or hub bearings (BB is more likely) are at fault - the whole freewheel turns as you pedal, so it might as well be a fixed cog. Only if you're feeling all the resistance and hearing the grinding noise while freewheeling is the freewheel is likely to be the problem.

Have a look at step 31 in this manual: http://www.cycleslambert.com/download.php/...yTechManual.pdf The cup shaped seal shown in the picture is likely to be the one that's leaking on you (Assuming there's no evidence of fluid leaking out of the brake). Check to make sure the reservoir is completely filled with fluid too though that creates a slightly different behaviour where the bite point of the brake changes each time you pull the lever rather than a consistent initial bite point which moves in as the lever remains pulled... This probably contains the correct seal, but will have a bunch of other stuff you probably don't need: http://www.ukbikestore.co.uk/Product/0/a11...servicekit.html If the brake is within warranty send it to the shop you bought it from and get them to sort it.

Here's cheaper again: http://superstar.tibolts.co.uk/product_inf...;products_id=28 (Though according to bikemagic the pad material sometimes breaks off the backing - Superstar weren't the only manufacturer people on that thread reported the same problem with though, and I'd recommend their Magura pads over anything else I've used on my trials bike). Avid compatible pads cheaper here too: http://www.discobrakes.com/?s=0&t=0&am...2&p=85& Having tried disk pads from both these manufacturers, the cheapest pads are both acceptable, but not as good for bite as OEM organic pads...

I've seen the lever seals get draggy in weeks on 3 sets of brand new Juicy 3 brakes, so Avid lever seals may not be quite right (They still don't leak though). From the video it looks like the front seal on the lever piston is leaking. The piston has 2 seals, the first to apply pressure to the fluid so the brake works, the second to stop the fluid leaking out of the reservoir when the first seal has passed the reservoir outlet as the lever is pulled. If there's no leak to the outside the back seal is still fine. My advice is to replace with Shimano or Magura and never have to worry about crappy seals again...

Denguras tend not to be watertight, so mineral oil is the recommended fluid. Any mineral oil should do - Shimano oil, Magura blood etc. Citroen LHM is my fluid of choice for Maguras and Shimano disks... Never owned Denguras (And wouldn't plan to based on the mixed reliability reports).

Glad to be of help - the other wheelbuilding guide I recommend is a book sold as a PDF here - well worth the money as it's a proper step by step guide and gives instructions on building your own truing stand and a few other handy tools: http://www.wheelpro.co.uk/wheelbuilding/book.php Once you buy it he emails you the updated versions of the book as he makes improvements too ... If you want to understand the background theory have a look at 'The Bicycle Wheel' by Jobst Brandt too. I have a student doing similar work to part of this book for his mechanical engineering degree at the moment - he's got 3D finite element wheel models instead of 2D though, so the results are more interesting and correlate well with real world measurements too ... I still can't believe I've got away with making this stuff part of my job ...

The cranks would be useful but not really useful if only fixed sprockets were available. It's even more of a pain to remove freewheels than fixed sprockets from screw on cranks. On further checking I found this: From: http://www.sheldonbrown.com/k7.html#hyperdrivec Showing some of the older uniglide freehub bodies which had a threaded top gear sprocket that also acted as a lockring. This set me wondering if the threads might happen to be 1.37" diameter... Just back from a trip to the garage - having compared them directly I can confirm that a freehub spline is smaller in overall diameter than a 1.37" BB/freewheel thread, but not by much, so the uniglide lockring threads may be borderline compatible with screw on sprockets, but making a 1.37" thread to freehub spline convertor definitely won't work... Pretty irrelevant, but at least I learned something new ... Now back to frame making - what sort of equipment do you have for forming/cutting material? Seatstays and possibly chainstays will need to be curved for correct clearances and depending on the look you're after curvy tubes are in these days. If there's no CNC then the mitering will have to be worked out... Some sort of jig to hold the frame in correct alignment would also come in handy...

If you have access to CNC equipment doing the frame in Aluminium will be less of a problem as you can use CNCed aluminium for things like the headtube area and the chainstay bridge where clearance is tight. By extending the CNCed parts down the tubes they join on to, particularly from the headtube area, you should be able to avoid having to put welds in areas of high stress altogether. It will also make cutting the frame tubes easier as you can decide the shape and position of the interface between the tube and the BB/headtube area and make it easy to align and weld rather than being at the mercy of your mitering equipment. This frame also presents the opportunity to design a chain tensioner integrated with the frame (Something very impact tolerant) if you're using vertical dropouts or a means of moving the disk mount as the chain is tensioned if you're using horizontal dropouts. I'd go with vertical dropouts as they give constant chainstay length and make aligning disk and brake mounts correctly a lot easier. I'm pretty sure the spline on a freehub is smaller than the threads for a freewheel on a crank, so making a convertor wouldn't be feasible (Though I'd have to check to make absolutely sure). Designing cranks with a freehub spline would be class - but only really useful if there was an ENO or product of similar quality manufactured to be compatible with it . The DMR Mounts are very solidly made and a great place to start. If there's a bolt on 4 bolt Magura or Canti mount to fit it and it'll do 24 and 26" wheels (The reason DMR designed the mounts that way in the first place), you'll have a frame that will potentially do everything...

Are you Eoin McLove? I heard you had no willy...

The quick guide: Lace wheel as required - it's quicker if you lace the spokes that go from the inside of the hub flanges first and make them all pulling spokes, as its way harder to put them in when the rest of the spokes are in. Make sure you have parallel spokes each side of the valve hole for pump access. For added pimpery the hub logo should be visible through the valve hole (Or maybe this is just me ). Set all the spoke nipples to the same position on the spokes - 1 spoke thread visible under the nipple is a good starting point. Set the flats of each spoke nipple parallel with the rim braking surface to make it easier to count turns. This also allows you to visually check the wheel for loosening spokes after it's built too. Starting at the valve hole work the full way around the wheel tightening each spoke two turns (If the spokes are really slack). When you get back to the valve hole you'll know you've made a full round. When the spokes start to get almost tensioned change to 1 turn at a time (This is about the maximum you should adjust a spoke while the spokes are carrying any kind of decent tension in wheel building anyway). When none of the spokes are slack, but not before then worry about the trueness of the wheel (If the wheel is blatantly out of true or one or two spokes are tensioned while all the rest remain slack, either the lacing is wrong, you have a couple of short spokes or you didn't start the spoke nipple in the right place). If you've laced correctly and started all the spokes at the same point there won't be a lot of adjustment needed anyway. Keep going until the spokes feel properly tight (Compare with a decent wheel you have already to get an idea how tight you can go). If you tighten a spoke too far the nipple will round before anything else fails unless you're running a really lightweight rim/hub/spokes.

The snowflaked stuff won't take the shock loads from trials as well as standard lacing. Fixed hubs make no difference to the lacing required (Though if you want to get really detailed whether you have pushing or pulling spokes laced to the inside of outside of the drive side flange can have a bearing on the amount of damage the chain does if it comes off the sprockets - pushing spokes to the outside of the hub flange is probably the best for a fixed hub front freewheel and for rear freewheel setups, while the opposite is better for fixies - the difference is borderline irrelevant in reality though).

If you're running a disk 3 cross is the minimum unless the hub and rim are specifically designed to handle disk forces with a 2X build. If it's a 32 hole hub then I'd build it 3X everywhere. Avoid radial spoke lacing for back wheels or front wheels with disks. If the hub you're using isn't specifically designed to take radial spokes then don't lace the wheel radially even if it's on a front rim brake (The angle the spoke leaves the hub at for crossed patterns means that the spoke has a lot more material supporting its load than if it's pulling radially). My own bike has 32H wheels laced 4X by Tartybikes and they're perfect except that 4X lacing puts the spokes at such an angle leaving the hub that they lock in the head of the next spoke over from them, making replacing spokes a bit of a pain as you have to loosen spokes near the one you're replacing just to get the remains of the old spoke out and the new spoke in. On a 36H wheel 4X lacing usually doesn't lock in nearby spokes, so it's an option. If you're building wheels for the first time make use of the instructions on the sheldonbrown website and on here for building wheels. A good wheel build takes patience as it's quite a repetitive process as the spokes have to be tensioned a small amount at a time to avoid pulling the rim out of round...

And well you might - I know where you live...

Opening Pro 2's is pretty much the easiest thing ever. Take wheel out of frame. Pull end cap off the drive side axle (It's held in place by an o-ring inside the end cap that fits into a groove in the axle, so it might need a bit of leverage to get it moving initially. Grab the freehub body and while turning it in the freewheeling direction, slowly pull it off the end of the axle...

That was probably Tha Goat - what with him being the only other Irish guy out there...

Pneumatics tend to be very lossy though - unless the pneumatic system provides extra drive separate to the pedals. Pneumatics tend to have very poor efficiency in terms of giving back the energy the compressed gas contains as useful work.

That would be me - haven't given myself a shinjury in well over a year and this one was a doozy ... Best type of injury - it looks nasty, but doesn't hurt... I was stopped by two women on the way back to the hotel wondering if I needed an ambulance though ...

Where are all the other photos? Everyone and their mother had cameras out on Sunday there must be a crap ton of pictures/videos around... Here's some full on heroism: http://www.skynet.ie/~ceason/photos/200903...ap_Pressure.MP4

The truvative system is called the Hammerschmidt. This is pretty much a cable operated version of a system called Mountain Drive (Again based on planetary gears in the chainset) that's been around for well over a decade at this stage. All internal gear hubs use planetary gear systems except for the CVT types, the only one in production for bikes is on some Ellsworth cruisers (Google NuVinci for more - I have serious doubts that this will carry decent torque and not suffer from hopeless efficiency or ludicrous weight (I'm pretty sure it's already very heavy), so useless for proper bikes). A genuinely interesting system to look at (It's been demonstrated to work, though reliability is the big question) is the Torotrak CVT car/4x4 transmission or the hybrid mechanical/hydraulic drivetrain Fendt tractors use for CVT. The Honda DH bike had a derailleur system enclosed in a box located inboard in the bike frame to reduce unsprung weight and increase resistance to rock strikes/vibration. The GBoxx standard as pushed by Nicolai is another thing to look at as a platform for new bike drivetrains. As for gear shifting, there's talk of Shimano releasing an electric derailleur soon, Mavic did this about a decade ago and it was complete shite from a reliability point of view and that was when used on road bikes... I have a student working for me on designing an open system hydraulic gear shifter as a mechanical engineering project. A company called Red5 in Germany have a system claimed to be an open hydraulic system which retails (Shifters and derailleurs only), for about €1400 IIRC... Other interesting drivetrains include the retro direct system - 2 gears, get one by pedalling forwards and the second by pedalling backwards, very devious stuff, invented in France over 100 years ago AFAIK... One other very interesting system to look at is the rotor crank system, which eliminates the dead spot at top dead centre/bottom dead centre (TDC/BDC) by having the cranks move so the pedal that's moving upwards goes faster than the one that is being pushed downwards, meaning that when one crank is at BDC, the other is already past TDC... Animation explaining it here: http://www.rotorcranksusa.com/i1-rs4x.shtml There's also some weird stuff like this: http://www.fact-canada.com/Powercranks/pow...ent-cranks.html which offers potential to work if pedaling efficiency is all you're after but you never want to stand up on the pedals...

For anyone not following the really really long thread in the cycles section - Some mobile phone photos and videos here - there's one 5:30 video with Kenny Belaey and DannyMac swapping bikes, Rowan Johns nailing a brakeless sidehop to manual and loads of other random stuff - enjoy ... http://www.skynet.ie/~ceason/photos/20090301_LondonRide/

Some mobile phone photos and videos here - there's one 5:30 video with Kenny Belaey and DannyMac swapping bikes, Rowan Johns nailing a brakeless sidehop to manual and loads of other random stuff - enjoy ... http://www.skynet.ie/~ceason/photos/20090301_LondonRide/