Tomm

Hey guys, here's the blueprint for a perpetual motion machine. Prove it wrong.

There's a difference between "scene" and goth now? Who knew?

If you're coming back and forth, just take the bike in a box on the plane? It'll cost about £20? David, I paid £18 but that was within the UK.

I just sent a bike. For reference the normal-looking bike box was 131 x 69 x 26 cm and it weighed 18kg inc my DMR jump bike which isn't particularly light.

The original iPhone.

Yeah, that's useful, cheers. I just wondered if you rode in the peaks since your profile says you live in Sheff (Hmm, thinking about it my profile says Manchester and I haven't lived there for 2 years). I've got a Mavic 729 and a Sun Singletrack at the moment - massively overbuilt for XC. I'm thinking about getting 719s or 819s (essentially the same but tubeless), there's not a massive difference in price so thought I might give tubeless a try.

I tidied up the ridiculous bickering in this topic. Don't let it happen again otherwise there will be warnings handed out. As for the hops - you've clearly got reasonable balance because you are hopping side to side a bit, and backwards to balance. It's pretty difficult to backhop forwards without pedalling, so when you're overbalancing that way you can't correct it and the front wheel falls to the ground. The next step is definitely to put a pedal stroke in. I never found the pedalling-without-hopping thing particularly easy, I always found it easier for balance when you do it WITH a hop (you'd be less likely to fall to the left/right). Try this: On the flat, trackstand with the brakes on Put some pressure on your front pedal, still holding the back brake. Now, if you let the brake off, you'll move forward because you're pressing on the pedal. This "pre-tensioning" the pedals is crucial for more or less every advanced technique. The next step is to co-ordinate this movement with leaning your weight back/pulling up slightly. If you do it right, the front wheel will come up, and the back wheel will come forward about 12-18 inches, and come underneath you. You can either hop or not, it doesn't really make much difference but I always felt that you could set your balance a bit better if you did hop. At this point you need to grab a handful of back brake to stop you falling over backwards. That's the basics. Once you're comfortable hopping into an upright position, you can try the same sort of movement (tension pedals, release brake, hop, catch the bike on the brake) to hop forwards. To get a feel for how much you need to pedal, you can learn how to do wheelies. Just to get the feeling of the front wheel coming up.

Where do you work Craig? I ride a lot in the peaks and quite a lot of it is spiky pointy rocks. I get pinches (on the rear) probably 1 in 3 rides, enough to think about alternatives. But I don't know that I would trust non-UST tyres for peak district riding. Maybe trail centres/smooth wooded trails.

Had a look at Superstar - their brake pads are fine and I've heard good things about their chain devices. Not sure I would use their hubs though? I'm a Hope (or Chris King!) kind of guy. Perhaps on an XC bike it's not so important. Anyway, they're out of stock. They do seem to have some pretty good offers though. I'm not doing it ghetto. 1) it seems like a massive faff 2) I'm buying new rims anyway, might as well pay the £15 extra for tubeless compatible.

I know someone who did it for a while. It depends where you do it - in most places local knowledge and being friendly/enthusiastic/approachable are important, and if you can fix a puncture that's a bonus. Fitness and bike skillz aren't super important for guiding - I suspect in the UK you have to have some bullshit qualification but I don't think my friend had anything (for Spain). On the other hand, coaching is a different matter.

I thought that but, uh, it doesn't. I did some sums today. Basically your tubeless rim is approximately the same weight as a normal rim - a Mavic XM819 (UST) is listed as 10g lighter than a 719 (standard). You don't need rim tape (you might save 30g) but you do need goo (60g ish) so let's call it quits. So it all comes down to tyres and tubes, and this is the kicker; tubeless (UST) tyres are approximately 200g heavier than non-UST alternatives which is exactly the weight of a standard inner tube. Take a 2.35 high roller single ply for example - The normal one is quoted at 740g, whereas the UST one has thicker sidewalls so it's 950g. If you google it, there are quite a few people using non-UST tyres on tubeless rims - that seems like a good possibility and at least you'd save the weight of an inner tube, but by all accounts they're perhaps not as reliable, harder to seat properly, and are more prone to air burps etc. Doesn't work with the ghetto way, either. So the advantages seem to be all about puncture protection and being able to run lower pressures, the downsides being that it's expensive and a faff to change tyres (if you use sealant) - the weight is about the same either way. At the moment my plan is to try it with a normal high roller on the front, and perhaps a UST one on the back. That way at least I'd save a reasonable amount of weight on the front, and the back one won't be any lighter but will be pinch-proof.

Carrera bikes are fine, I've got a road bike made by them it was great value. At that price, you're never going to get anything that anyone's going to lust over (sorry to say), and as you say, the specs are all pretty similar. So find a good deal, try it out for size and go for it.

Not massively overpriced if it's in perfect condition. Those were seriously posh hardtails back in the day, and that's basically pro spec. But yeah, I wouldn't want one, and it's probably a bit of a steep price for a pretty old bike. Mind you, I don't know what the second hand bike market in the Netherlands is like...

I want to do it properly if I can - get proper rims and proper tyres, mostly just because I need new rims and that's what got me onto thinking about it. I've read a few posts that suggest that non-UST high rollers work fine as tubeless, even without sealant. Did you have to use a compressor? Apparently with proper UST you don't need to, even without sealant. Have you seen these tubeless puncture repair kits? http://www.chainreactioncycles.com/Models.aspx?ModelID=7971

This is exactly the reason that as a doctor, you shouldn't request tests for people who are not unwell. Essentially you've demonstrated that pre-test probability has a huge effect on the predictive value of the test. Which is why tests that work in a hospital setting will often be useless in screening the general population. It's also why having a full body CT scan for no particular reason (as many private companies will offer in the US) is a stupid thing to do - consider the risk of 'false positive' results and the unnecessary investigations that might result. Chris4stars has it right. You can demonstrate this by drawing a 2x2 table: Totals add up to 100,000. Disease -ve +ve Totals 99 900 100 Disease -ve +ve Test +ve 999 99 Test -ve 98901 1 Take the horizontal line for 'test +ve' and you can see that there far more people in the 'disease -ve' column. This is a complicated problem - even more so when you consider that your 'false negative' and 'false positive' rates are often wildly different (in your example, both are 1%). Tests are very rarely 100% positive or negative - most biological parameters are continuous variables and you choose a threshold, below or above which a test is considered to be positive or negative. Depending on the context, you might want a test with fewer false positives, and you would have to compromise by allowing more false negatives. In theory, you're right. However, you have to consider that in a biological system, two test results from the same patient are likely to be the same - if your test was a 'false' positive, it's likely because of a 'patient factor' (strange antigens etc) rather than simple probability.

Right, tubeless. 5 years ago, this was the 'next big thing', but I don't know a single person who uses it yet. It seems so obvious, but there are clearly downsides I don't know about. I've heard the air burp thing, does that happen at XC pressures (35 psi)? And obviously they're harder to fix (take a spare tube). I'm thinking about building some new MTB wheels and I fancy trying tubeless. So: What are the downsides? Goo vs no goo? As far as I can work out, I need a rim, tyre and valve adaptor thing. Is that it?!

Yep. And even that can be subject to credit card chargeback scams (google it if you care). I used to think insurance against scammers was the reason Paypal took a big cut for doing... not much. I once got stung, bought something online, paid via paypal because I thought it'd be safe. Item never turned up, the guy basically disappeared and closed down his paypal account, and there was zero I could do to get my money back. The paypal dispute found in my favour but they said although they had tried to get the money back from the scammer's account, that had failed and I was on my own. Utterly useless.

Lulsec isn't scary, they were a bunch of amateurs. This is scary: Stuxnet

My XC bike has had duct tape rim tape for at least 3 years now, no problems. Electrical tape is a different matter - don't use that. Usually you can tell by looking at the puncture itself - little bubbles where the inner tube has 'herniated' through a hole in the rim tape result in funny star-shaped punctures.

If you actually are going to quit, you may as well call unfair dismissal or something. Or you could man up and go back, and have a talk to your boss man about how inappropriate it was. Although obviously I don't know whether the situation would allow that...

The servo-wave brakes do have a bit more squidge than others, but I wouldn't say they feel at all bad. Shimano brakes come with really long hoses F+R (so you could run a RH rear lever and vice versa) and shops either sell them like that (and you have to cut them down) or they cut them and bleed them. I know what you mean about bleeding brakes. It seems so simple and yet it never works out that well. I quite like bleeding Avid brakes, though.

You would have to spend £2k + now to get that spec. Ive been debating a new (full bounce) bike but £2k seems to get you really average spec (slx gears, basic rock shox eg revelation). I can't get excited about Cube bikes. They look more 'race' than 'fun' to me. Depends what you want I guess.

My mate's got a Foxy FR and it seemed really nice when I had a look at it. Felt quite similar to the Lapierre, at least geometry-wise, although I've not ridden either of them for any great length of time. However, the guy who owns it managed to snap the mech hanger after 1-2 months. He's been without a bike for 3 months because it's currently impossible to get a replacement hanger for the Foxy - Anywhere in the UK! He tried loads of dealers, even the distributor couldn't get hold of them. Ridiculous. In the end he's converted his axle so he can run an old (obsolete) Saint mech which bolts straight onto the axle. So yeah, although they look nice, for that reason I wouldn't bother. I used to have a 2005 (?) Kona Stinky which is basically the same as what a coiler is now (5.5 - 6" travel coil sprung faux bar design). I rode that in the Alps (loved it) and for XC (hated it). It's basically a completely different beast to the commencal. I think you have to make a distinction between absolute weight and what a bike feels like to ride. The meta is lively/spritely, loves going up and down whereas the Kona was dull, lifeless and energy-sapping on climbs. So even if you could build a coiler up to weigh less than a meta (and you probably can, the frame weight difference is only going to be 2-3lbs at a guess), it would still be a pain in the ass to ride XC. My personal opinion here: I don't think you buy a "trail" bike (140mm ish travel full sus, air shock) because you like riding downhill. If you want a bike you can pedal slowly up a fireroad to the top of the next descent, there are better options around the 160mm mark (Giant Reign X, Specialized Enduro, Lapierre Froggy, Meta 666 etc). But for me, those bikes sort of miss the point of mountain biking. Ride up, ride along, ride down, enjoying each bit. All day epics out in the wild. Quick blast around your favourite local trails. 140mm just seem to hit a sweet spot for me, not too cumbersome on gentler rides, and still 'enough' on big stuff. I know that's very much an opinion though, and it'll depend on what the riding is like near you. Having said all that, I own a DH bike as well - If I didn't, I might feel differently. If I wanted one bike for everything (All day rides, the occasional uplift day and an Alps holiday), I'd probably be looking at one of those bikes I mentioned, but I'd have to accept that there's a trade-off. I have to add though - I was exactly like you before I discovered how challenging it was to try and "clean" technical climbs. That changed with the Commencal. It begs you ride up stuff you never thought was do-able. I know you won't believe me, but sometimes I prefer the feeling of nailing a hard climb to smashing down a difficult descent! Nope. You just have to accept the mantra "Strong, Light, Cheap. Pick two". The Commencals are reputably bad for breakages, but there are always going to be some frames snapped after 2-3 years from all manufacturers. Every manufacturer does one, there are no lemons from the big guys. Specialized Stumpjumper / Pitch Lapierre Zesty/Spicy Giant Trance /Trance X / Reign Santa Cruz Butcher/Blur Commencal 5.5 Orange Five GT iDrive Marin quad-whatever Kona Coil-Air Intense 5.5 Mondraker Foxy Transition Covert Writing that list has reminded me: Specialized Pitch. Get one - it's perfect for you. As long as you ditch the Radium shock on the cheaper version (you can try a coil shock if you're that way inclined), they feel really nice and they're a complete bargain. You can get a used frame for £300 easily (Get a Pitch 'Pro' for a decent shock). It's basically an Enduro from 2-3 years ago.

The ones that are here genuinely for the riding have no problems* - we'd love to have more female members! It's always going to be a difficult mix when the female: peripubescent boy is 1:1000 though. *I havent owned a trials bike for a couple of years now. I'm aware of the hypocrisy so don't bother pointing it out