jmaccelari

Jules has asked me to look at this problem. I am a physicist and applied mathematician so it's right up my alley. The bottom line is that taking mass (weight) off the wheel is more effective than just taking it off the frame (my example shows it is twice as effective). This is because we need to add translational and rotational kinetic energy when accelerating a bicycle - they are separate systems and have their own conservation laws. If we reduce the frame or cyclist mass we only reduce the translational kinetic energy, whereas if we reduce the wheel mass, we reduce both the required translational and the required rotational energy - a double whammy. The mistake in the thread was to ignore the rotational component! It is small compared to the total energy equation, but is comparable to the translational energy saving so cannot be ignored if we are looking at energy savings! I have attached a document with the problem detailed and a worked example at the end. I hope it is clear to all and sundry - if not ask me for an explanation! The thread then ambled on to power calculations which are merely energy equations differentiated with respect to time, so the same conclusions will hold if we look at power. The document can be found at: www.cyclesafe.co.za/wheel_physics.pdf Just to prempt those who are going to fly off without reading the document: - the effect is SMALL. At best in a perfect world taking weight off the extreme outside of the rim is only twice as effective! - it's probably better for most of us to leave our socks at home than try to shave a couple of grams off our wheels. It'll be cheaper... jmaccelari2010-01-04 09:27:06

The mind is a powerful thing. Sometimes snake oil is the best solution. It's healthier (and more legal) than taking drugs!!!

From Knysna, Simola Pass and Di Ou Pad are a brilliant ride. There's also Millstream (I think it's called - the old gold fields area).

Nope - for the Tour de Tjop!

No technical reasons. but I find centrelock very convenient and easy to use.

There's a small bike shop in Sedgefield that has a map with several routes in the Karatara area that might be suitable. Depending on where you stay, the Hoekwil, 7 passes, George route could be an option. Or you could do Knysna, Phantom pass. Or you could just do one of the routes in Harkerville. There's quite a bit on the Plett side (but usually more than two hours). Go to Kevin Evans' shop and ask there. You are spoilt for choice!!!

Can I ignore this one and go my own, sad way now?

A very similar incident occurred to one of our guys a couple of weeks ago and it was a very nasty incident. I feel for you. Get well, and I hope the best for your recovery...

So you reckon a 29er would give you about the same advantage as a full susser 26"? The maintenance argument (hardtail vs full susser) is a very compelling one.

Why don't you just say "**** all that comparison BS" and go for a 69er (not that kind!): http://www.thebikelist.co.uk/trek/69er-single-speed-2009 Now THAT'S weird...

MTBer was actually in shock and nearly totaled his bike thinking about the site of greeting roadies No I reckon he just read flex's post...

Went on a long road ride this morning. All the other roadies greeted us back - the only exception was an MTBer... Flex was in the mood and was greeting everyone. AYOBA!

Nah. They just looked at the percentage of Hubbers with shaved legs and who like to wear tight lycra... Frikkin' fags...

I rode the Spruit this morning and greeted all the other people on their MTBs. Most sullenly ignored me. Do you reckon these were roadies on their MTBs or were the guys you met MTBers on their road bikes?

Here's a definition: ?public road? means any road, street or thoroughfare or any other place (whether a thoroughfare or not) which is commonly used by the public or any section thereof or to which the public or any section thereof has a right of access, and includes? (a) the verge of any such road, street or thoroughfare; (b) any bridge, ferry or drift traversed by any such road, street or thoroughfare; and © any other work or object forming part of or connected with or belonging to such road, street or thoroughfare; So, yes - the spietkop was correct... jmaccelari2009-12-30 07:07:05

Thanks' date=' "stole" it from Jim Morrison [/quote'] Isn't that Bumblebee? And to get back to the topic, I reckon the Dogma's a rip off...