Why train on a lightweight roady?

[airbrake]

Almost doubling the weight of a road bike makes a <1% difference in leg load on a rolling terrain ride overall....

That's true - if you can find flat / rolling terrain where you never have to slow down or stop for anything or anybody.

 

[BikeLiker]

I was making the assumption that the wind velocity was a constant and that the only velocity changing was that of the mass of the bike.

I believe that if you hit a 30 MPH head wind with one bike, and then hit a 30 MPH head wind on the same bike but at a higher velocity the increase in wind resistance is proportional to the velocity as stated in newtons second law, I believe this law is valid as the mass is not changing.

Net force on object = mass on object x acceleration

What is your reasoning, behind your perspective, just curious.

Whether the velocity of the air mass changes or the velocity of the bike changes is irrelevant, it is the relative velocities of the two that matter. Because air is a fluid it is viscously coupled to any object it flows around - the air doesn't stop when it hits the rider but slows them down according to the friction factor. In the drag equation (http://en.wikipedia.org/wiki/Drag_equation) the only value that changes for a fast and slow rider is v. As v is squared in the equation then the drag force will increase proportionally with the square of v, unless you go onto the drops then A is reduced also.

 

[albion]

Mudguards, 40mm Marathon XRs + panniers surely make my bike quite a bit over 16.5KG.
The Tyneside/Durham area with its waggonways and old rail tracks is surely 'hybrid country.'

I'm sure that most of us 'leisure it' and do not think of it as training.
My extreme 50 miles of road going out and 50 miles on the return.

A maximum of 50 miles on the hybrid is more the norm.
I'd really hate to have lack of route choice/increase puncture risk with a road bike.

 

[Nebulous]

I've got a 10kg roadbike, my leisure/ training bike with spd-sl pedals and I've got a 14.5kg tourer, my commuting bike, with flat pedals. The difference between the two is less than I would like it to be, and sometimes its pretty much sod all.

My roadbike was off the road for about 3 weeks earlier this year, not long after I got my tourer, so it was pressed into action for some longer runs. There's a Strava segment I've been determinedly working at off and on this year. 2.9km rolling terrain, up quite a bit first and then down at the end. I've done it 30 times almost all of them on my roadbike, and my best time is on the tourer.

 

[fenlandpsychocyclist]

Performance can 'stagnate' if we use our muscles in the same way - such as on the same bike on a particular loop. It's known that off-road riding on heavier bikes with increased drag improves performance on the road. I've forgotten most of the science behind it, but the benefits are there.
You could argue that using a heavier road bike would give your muscles similar challenges - and there's no reason why heavier bikes can't be fun to ride either - provided they are set up well.
In principal, change is good - and as we all know 'change is as good as a rest'

That sums up my thoughts exactly!
I have two sets of wheels for my mountain bike.
Its 3 minutes work to swap from lightweight rims with slick tyres, to my heavier rims with sticky knobblies.

I recently tried a 30 mile tarmac ride on sticky knobblies (2hours 45 mins) and i was still aching 2 days later from it.

On the other hand i did a 100 miler the other week on a normal road bike setup (7 hours 10 mins) ... and just had a very slight
ache in my left knee the next day.

In my opinion the first ride "broke some muscles" hence the aching from them whilst they healed.
The second ride on the other hand was a case of "no pain no gain".

As for the enjoyment factor ... its back to the mountain bike and "offroading" along tracks parallel to my normal training routes.

Each to their own eh?