well i never

[Spike16]

not sure if anyone is interested but after looking over the weight list thread it go tme thinking, how much does weight reduction really affect the bike (i knew it does but wanted to see some figures about it)

so i did a simple test, rear wheel rotating momentum and the force required to turn it at a given speed (62mph cos it was easy to use 100kph)

i got the weights and sizes of a standard nc30 rotating rear end (ie wheel disk tyre and sprocket) and then i light weight super spec rear (bmc disk, dymag wheel, renthal sprocket and tyre)

the trick rear required 25% less force to turn it at 28m/s (62 mph) and had 18% less momentum

thats serious gains! + with the less momentum there will be less of a gyroscopic effect and so easier to make movement in x direction (ie lean and pick up)

bit of ige but o i found it very interesting, + confirmed some of the things i did in my exam this morning were correct.

[CMSMJ1]

Give us some of the data then dude..

You know we want to get uber geeky on it..lol

If you want to get super geektastic then please get a look at the gains in rotating weight between a camshaft with quietening gears and one without

[Aether]

That is pretty interesting, but are you some kind of crazy scientist Spike?!

I used to be pretty into cycling, and it was a given that the first place you wanted to upgrade was always the wheels, less weight meaning less force required to turn them etc, you really could notice the difference.

You've sold me, now if only I could afford a superlight trick set of wheels...

[Spike16]

err no im a 17 year old student lol

well hopefully by tomoor il have the weight of an nc23 front wheel which i can compair to the standard ones (im told its lighter) and find out how much that affects it, although as its not driven the effect will more be about deceleration (braking)

mark if u can get me the weights of the camshafts, the dimensions of the quitening gears aswell as the camshafts and the speed average they spin at (say at 8k), its pritty simple

just use force= mass * velocity squared all over radius

and momentum= mass *velocity (but thats not rotating, just normal)

o and dymag? renthal? if your out there pm about picking up my free stuff for the advertising lol

[CMSMJ1]

I will get some stuff sorted mate ref the camshafts etc. I am curious to know what kind of figures it comes out with.

Heavy wheels on an MTB are useful when you are as cackhanded as me..and hav an addiction to jumping down large sets of steps

[Spike16]

tell me about it, my mate just got a new specialised stump jumper (£1500 aprox) for him to go across africa on, i took it down a 5 stair set and pringle the frong wheel lol, he wasnt happy lol

it was so bad the rim split all the way through, even the spokes couldnt be saved

but back to bikes...the camshafts will be interesting cos they dont have a large range of speeds (like wheels about 30-130) so it will more be about the force required to turn the camshafts at a certain speed, with smaller variations in speeds

does anyone know of a wheel that will fit the nc30 cheeper than dymag/magtek etc and is lighter than an nc30 wheel, bit like the 23 front..what about nsr250 wheels?

[CMSMJ1]

the 3 inch rims from NSR adn the RC30 will prob fit? 16 inch blade wheel does with some spacers..and I have one of them in the garage. Will weight it tomorrow as well...

[Spike16]

nah im talking rear, but go ahead and weight them, see which is the lightest oem wheel to fit an nc30

[Spike16]

mc28 hub looks similar

http://www.dreamgate.ne.jp/NSR/specs/MC28rearbrake.jpg" onclick="window.open(this.href);return false;

and the wheel is a 150/60/17 which would make it a decent upgrade to the nc30's

and arnt they HRC magnesium's standard

[tanuki]

The mc28 magtek is a direct bolt on to the 35 and 30 I should know I have a pair on my 35 its basically exactly the same wheel as a standard 35 but is obviously magnesium, if it any help the rear is almost exactly 1 kg lighter that the standard the same goes for the front when comparing to the standard mc28 front, but they will be lighter again than a standard 30/35 wheel as they are 3" as opposed to 3.5"

HTH