Tieffels

On another thread people where getting their panties in a knot if the race distance is out by 25m, and now you guys want a technical rating? So you enter a race thinking it is a 3.5 out of 5, and you end up feeling hard done by because you felt it to be a 3.8... Seriaas? What happens if you are out on a training ride and hit a hole that was not there last time, who's to blame then? CSA? Julias? Apartheid? What happened to riding within your ability, if you have control over your bike you'll be OK for 99.9% of the time. Ja, bad things happen, people hit bars that should be marked, people hit holes that should be marked, people lose their money in recessions.. But I mean for goodness sake, it is mountainbiking, there are risks, grow a pair.. Where is that Bustthesickness character when duty calls?

Lekker hannes Is the pressure in the inside of the rim + ve or -ve? Also it would be interesting to see the effect of allowing the hub to displace downwards with a force representing a rider + impact acting on it and keeping the contact point on the rim fixed...

I suspect you misinterpreted the deflection zone, as in the length of the beam (or rim) that is affected by the deflection, with deflection, as in the amount of movement in the radial direction. What is implied, and what I agree with, is that a weaker rim will deflect across say 2 spokes as it is not strong enough spread the load across say 4 spokes if it was stronger. This number of spokes involved is what JB referred to as the deflection zone.

Before I start where you want me to start, let me start by saying thank you for being a big enough man to admit that you were wrong. Or sort of implying it, as it is the hub way of saying sorry. I do not agree with JB's statement 100%, but so far I'd say he's addressing more of the picture than some other arguments. In than rhetoric of his that makes him loved by all on thehub. The spokes affected by a big impact to the rim, with the number of spokes affected determined by the stiffness of the rim, will loose tension, but I suspect than the tension the rest of the spokes need to gain to "take up the slack" as it were, is considerably less because this taking up the slack is shared across more spokes across the top arc of the rim. Cheers The way I see it is that what both camps are arguing for is taking place..

I agree with you 100%, you cannot change the law of physics, no matter where you start, but your understanding is a different matter. And that is what I meant by when I said your understanding of the matter is affected by your mental approach to the problem.. I suggested an alternative to your analysis and in the process pointed out errors with your analysis (i.e. the deflection of the rim playing a massive role in the analysis) and tried to bring in the correct (according to me at least) observations and conclusions of previous posts. Feel free to comment on the analysis side. PS you have to define your system that is in equilibrium because the wheel is not in equilibrium in most instances. @ JB. My bad, you are indeed correct re the rim strength issue @ The Mavic 819 supporters: I went through great effort to import 2 rims from the USA as they are insanely expensive here. My rear rim cracked down the middle of the rim, in the plane of the spokes, in 15 months. Internet search and talking to my LBS revealed it was not uncommon. Wanting to stay with the tubeless sytem I got another one. Also did not last, somehow bent it way out of wack. This is only my personal experience, yours will differ.

motionbased was quite good, now you have to use the garmin connect thing which is not so lekker..

Ja, your understanding of the concept is greatly dependant on where you start with the analysis. You start at the hub and work towards the rim, I suggest start at the rim and work towards the hub.. In what you said above you assume the rim is quite rigid, which it is not as per JB suggestion and the FEM thingy. As the rim is subjected to a load from the ground, be it your weight or a rock at the bottom of a drop, the rim deforms and displaces inwards towards the hub, relieving some of the pretension in the spoke affected by the deflection zone of the rim. And the stronger the rim, obviously the smaller the deflection zone and less spokes are affected. Also the rim might bulge out due to conservation of mass as per the FEM pics, so the tension in some horizontal spokes also increase. As per your previous posts you understand force vectors, so now you simply sum the vertical components of the tension in all the spokes and that is the force that the hub sees and transfers to the frame of the bike, which is countered by your weigh or slows you down in the case of a drop-off. Easy

MBP I feel your pain, if there had not been a bunch in front of me I'd be joining you in group chiropractor sessions. What astounds me, apart from your grievances, is the marshal right there did not recognize the need to warn people..

I have a kneejerk reaction against ANYTHING a bike shop says, as the BS in LBS does not stand for Bike shop. So here goes my very honest question/observation: So this salesperson implies that a bike company that has years of bike design experience has no idea how the geometry of a bike affects the handling of a bike? I mean, that is all they have to do, all day, every day, and they are just guessing away, hoping for the best. I mean really.

I take it that english, she is not your first language? Also either you are lying about the whole heat dissipation thing or my heat transfer lecturer was. But then again english was also not his first language...

At R4200, what comes with the 705 bundle, esp maps wise?

I found that by just keeping on riding with chainsuck, it eventually stopped. Might have had something to do with the fact that I ripped of my rear deraileur but who knows...

To add to the body of experience: <?: prefix = o ns = "urn:schemas-microsoft-com:office:office" /> Before the Epic I needed to do the conversion and could not find a 20' Presta tube so I settled for a 24' Presta tube which are widely available. Worked like a charm. I've never done it with a 20' tube so can't offer a comparison. I did not even trim of the 10mm of tube sticking out past the rim as I hoped for some extra side wall protection. The foreigners loved that... Used a standard tyre on standard rim, no problems. On stage 6 i managed to snakebite the tyre 2km from the finish, just plugged and bombed it, no problems.

Yeah' date=' I'm 1.89m and weigh just under 74kg . [/quote'] That is crazy, I just about cannot picture that. I'm a touch under 90kg and 1.84m and I consider myself quite a strong climber (mtbing where I think the weight penalty is less severe due to more brute power), but at those weights you guys must float up hills. But at my weight I know weight off the bike makes no difference and I laugh at those guys sweating over every last gram. If I had to lose say 2hg the difference would be from the extra training to lose it, not the weight itself. It's all mental..

Buying new wheels to increase your free-wheeling speed.. That is a new sales pitch/motivation for me. But seriously, older well worn hubs should free faster than new hubs because the seals are worn out. Slight resistance in bearings indicate the seals are still effective and contact the race moving relative to the seal. This is what they are meant to do.

Since we're all name-dropping here, I've riden with the following legends in the last year: Christoph Sauser Burry Stander Karl Plat Stefan Sahm Nino Schurter Booya!

Gobi works for me, MUCH better than initial Specialized and cheapish Sella Italia.

Cost of table at charity fund raiser with Lance Armstrong : R15 000<?: prefix = o ns = "urn:schemas-microsoft-com:office:office" /> Receiving a massive serving of the real bad-ass world by having your ideas about your hero shattered: Priceless

Mmmm, Gobi would be a better buy over the long run IMO, but the Assos might be less dicy to try new on a stage race. Buy the Gobi and try it out this weekend, I think it is an awesome piece of kit.

I was going to ask the same question Fair question, one I often ask myself.. My entire year's bursary paid out in March, and a buddy got an early bird entry so I thought bugger it, I'll figure it out later.. It's been fine so far, thanks to Mr Bornman, and AJ's mix (which reminds me... Knersis...). But now I hear all these gospel stories about massages and bibs hand made by buxom virgins high up in the alps equipment and what not.. <?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

So how about a product sponsorship for the poorest team in the Epic? We'll write you a lekker review and publish it here on the hub?

Ja, that is a bit of a joke, it takes longer for it to get from the depot to your post office than from the UK to there.. The internet tracking through is only till the INT mail centre, so often the package as lying at the local PO and they take 3 days to get the slip to you while you still think it is in JHB. Last time what I did is to just rock up at the PO with your tracking number after about 3/4 days of it arriving in Joburg. Then 3 days later the slip only arrives at the door and the kit you got is already a couple of days old!!!

Looking down at Groenlandberg, the one in the background across the Grabouw dam (name?). Taken yesterday from the top of Hans Kop. Still have a slight cranial buzz from the receivers up there. Bring on the Epic!!

My current thinking: Compare the 2 scenarios of race vs head tube cracking first. <?: prefix = o ns = "urn:schemas-microsoft-com:office:office" /> 1. Suppose head tube crack first: Would that lead to a cracked headset race? I think not, the race is still uniformly loaded and the cracked head tube will not cause a stress riser seen by the headset race 2. Suppose the headset race cracked first: That means all the forces seen by the headset will result in an opening in the race, placing a lot of concentrated stress on the headtube. Aluminium as you all know is not a fan of cyclic stress, and then the crack. As pointed out earlier, just because it is such a neat crack (the headset) does not indicate that it happened later. Even with constant expanding and closing it will stay pretty much perfect. My money still on 2.

Thanks bontie, will have a think about it. The problem is living in the Western Cape and smelling like meths the whole time will get you locked up with the rest of the bergies..