Bike porn

Dammit asked about energy turned into heat, and i gave a slightly trolling answer. The key bits were assuming negligible pedalling, and 'on average'. The average is taken over the whole descent, including the bits where the riders aren't braking...

In more detail:
mass - the MTB is heavier, but both bikes are light compared to their rider, so the difference in total mass is small.
energy - i'm assuming no pedalling, just looking at the gravitational potential energy, so with a bit more mass the MTB has a bit more energy to get rid of, but it's close.
Rolling resistance - the sum of all the non-braking constant forces that resist motion. The MTB has more, but the work done against it is resistance force x distance travelled against it. With the road bike's much longer path length of descent, it's not clear which will loose more energy this way.
Drag force - air resistance and any other forces that go roughly with the square of speed. To calculate the work done against it you can integrate it over the path length of the descent. It will be much larger for the road bike because even though it's more aero, it goes much faster and further.

Brake heat energy - what's left of the starting potential energy after the above have been accounted for. It's clear the MTB will have more.

You're answering a more relevant but slightly different question about how hard the brakes have to work.

I don't have an understanding of physics capable of properly discussing this I guess.

I was working on the assumption that you could ascribe (say) 600W to each rider as the acceleration they gain from going downhill.

The MTB rider is going to put a lot of that into rolling resistance, the suspension, the air resistance of being in a upright position and so forth.

The rider is still going to be hitting 65km/h I would think, for brief periods, but the rider will take much longer (proportionally) than the roadie to get there.

The roadie is going to be more "efficient" in using the 600W to go faster- they'll lose a lot less, essentially.

They're also likely to be adding significant power of their own, especially out of hairpins.

They'll be hitting ~90km/h, frequently.

I suppose, thinking as I write this, that the MTB will quite possibly brake for much more of the descent than the road bike, putting a lot of constant heat into the brakes whereas the road bike will put a much larger amount of heat in, more infrequently.

So I suppose the question is of the two which would exceed the brake systems ability to shed heat before the rider gets to the bottom- i.e. which one goes over the edge when the brake fluid boils.

what is the finnish/paint on this? I've seen Sizemore bikes looking a bit the same.

ezra is fond of tool blacking.

Gun Blue'd. Used for rifle barrels and such. Got a bottle at home from trying to do it on a frame but the finish didn't really turn out that great.

http://www.ebay.co.uk/itm/Birchwood-Casey-Perma-Liquid-Gun-Blue-Rifle-Care-/360124459541?pt=UK_SportingGoods_Hunting_ShootingSports_ET&hash=item53d9172a15

thx. Ill look into it

Lovely bike, I'd prefer chromed rather than matt silver bars though

thx. Ill look into it

Here's kind of a guide. http://www.flickr.com/photos/reefflop/4708058308/in/photostream/

bikepack.pl is cheaper I think.

And a much bigger pain to gain access to.
And often too small.
And are you really going to notice a couple hundred grams?

Another millionaire wall hanging..... No pedals = not a bike!

no?
pic above it had no pedals, is that a bike?

or a wall hanging?

needs classic cranks for sure, looking to buy it

pedalroom

That's the loveliest bar shape I've seen, would loce to know the make.

^^I love bikes as much as the next man, they are beautiful machines and should be ridden, even if only on dry sunny days (rarely!). It's the lack of any intention to EVER fit pedals and actually oil a shiny chain that pisses me off. The buy pristine everything/put together with white cotton gloves/polish inside of threads/hang on wall culture means many less bikes to ride and pushes prices up.

many less bikes to ride and pushes prices up.

The Chinese are making millions of new ones every year, and they keep getting better and cheaper.

HVZ Steel. A russian brand. HVZ is an acronym for Harkov Velocipyed Zavod/Harkov Bicycle Factory...

That's the loveliest bar shape I've seen, would loce to know the make.

nice

^^I love bikes as much as the next man, they are beautiful machines and should be ridden, even if only on dry sunny days (rarely!). It's the lack of any intention to EVER fit pedals and actually oil a shiny chain that pisses me off. The buy pristine everything/put together with white cotton gloves/polish inside of threads/hang on wall culture means many less bikes to ride and pushes prices up.

This bike builded for indoor/outdoor cycling track only, not for street

^^I love bikes as much as the next man, they are beautiful machines and should be ridden, even if only on dry sunny days (rarely!). It's the lack of any intention to EVER fit pedals and actually oil a shiny chain that pisses me off. The buy pristine everything/put together with white cotton gloves/polish inside of threads/hang on wall culture means many less bikes to ride and pushes prices up.

don't get pissed over things like this,
Life is too short

This bike builded for indoor/outdoor cycling track only, not for street

My track bike's only ever been used on the track. I still find the fact it has pedals quite useful though...

Enough already! One of the few compensations for advancing senility is becoming a grumpy old git. I won't physically post the 'no pedals' comment on another bike, but I will have in spirit.....

"feisty fellow you are"

Yoda

For me & saarf:

tell 'em son
x
nb

saw a loverly Mapai t'other day, was Cristal so bottom of the line, and vendor another mercenary dog so swerved it

That is huge, photo angle I think made it look very laid back.