Why train on a lightweight roady?

[fenlandpsychocyclist]

Surely buying a expensive lightweight bike to loose weight is like going to the gym for a bit of
weight training and only lifting the bar?

What if you'd have bought a cheap fully kitted mountain bike at 16.5kg ... but then did the same
distance as you would have done on a 8.5kg road bike during every outing?
You'll probably ride at the same "perceived effort" but with the extra aero drag and hill climbing weight
the average speed will be less.

My garmin edge 800 has been set up with the weights of my three bikes.

If i ride a 30 miler at 70% of max heart rate, my 8.5kg road bike burns 900 calories (average 17mph).
If i ride the same 30 miler at 70% of max heart rate, my 13.5kg road bike burns 1300 calories (average 15.5mph)
Again, if i ride that same 30 miler at 70% of max heart rate, my 16.5kg mountain bike burns 1700 calories (average 13.5mph)

Basically by choosing bike 3 over bike 1, i'm taking 15% longer on a ride, but burning almost
double the calories.

As a side note, my garmin 310 watch gps seems to over estimate calories burnt ... i understand
it doesn't take into account heart rate whilst calculating calories burnt, whereas the edge 800 does?

 

[GrasB]

at 150w ave power with max & min power +/-20% of ave -

8.5kg road bike - 914kcal
13.5kg road bike - 922kcal
16.5kg MTB - 1064kcal (+7 kcal for weight only!)

 

[MacB]

at 150w ave power with max & min power +/-20% of ave -

8.5kg road bike - 914kcal
13.5kg road bike - 922kcal
16.5kg MTB - 1064kcal (+7 kcal for weight only!)

are you sure you're allowing for duration variance there?

 

[Andrew_Culture]

I can sort of see where you're coming from, but riding a MTB on the road is like being punished.

 

[ohnovino]

If you ride for the same time (not distance) and at the same level of effort, aren't you burning the same calories irrespective of what bike you're on?

 

[GrasB]

are you sure you're allowing for duration variance there?

These are the times using a real circular 28.7 mile course with 6.2m climbing/km assuming no wind at 15C:
Road bike @ 8.5kg - 1h 42m 25s
Road bike @ 13.5kg - 1h 43m 05s
Road bike @ 16.5kg - 1h 43m 25s
MTB @ 16.5kg - 2h 03m 15s

PS. My edge 500 is just on another planet when it comes to calories burnt if I've not got a power measurement.

 

[BrumJim]

I can think of two reasons:
1) Heavy road bike leads to increase in strength, and higher muscle mass, whereas lighter road bike leads to increase in stamina instead.
2) Being familiar about effort required. If you ride a heavy bike you will necessarily go up hills more slowly. So get back on a lighter bike, it all seems very different, and you either over-estimate the improvement in power/weight ratio and blow up, or you ride up at a familiar speed and loose time.
3) Because you can. (This one obviously doesn't count).

A while back there was a story about someone filling the frame of a lightweight bike with some sand in order to improve training resistance. The bike then got nicked by someone who it is assumed got rather confused as to how heavy this Top of the Range bike was.

 

[User16625]

I can sort of see where you're coming from, but riding a MTB on the road is like being punished.

Exactly, its also like doing a track day in a land rover. The way I see it is using a road bike you will go further and faster in the same time. I have never done 50 miles on my mountain bike like I have on my road bike.

 

[doug]

Riding a light bike is more fun so I ride it more often and further.

 

[fossyant]

Garmins tell porkies about calories.

Lightweight road bikes have their place, on a road. MTB's have their place, off road !

 

[Andrew_P]

Is there any allowance between enjoying the ride and seeing it as a chore?

 

[Rob3rt]

For enjoyment!

To get used to the bike you are going to race on!

Because having one nice bike is better than having a mediocre one and a shoot one!

Because most of the people who state they are "training" aren't actually training for anything competitive and thus the enjoyment of riding outweigh's the performance gain!

 

[Mr Haematocrit]

What if you'd have bought a cheap fully kitted mountain bike at 16.5kg ... but then did the same
distance as you would have done on a 8.5kg road bike during every outing?
You'll probably ride at the same "perceived effort" but with the extra aero drag and hill climbing weight
the average speed will be less.

As speed increases so does air resistance which is directly proportional to velocity. If you think about it, the faster an object like a bike is moving, the more frequently and harder said object will collide with the molecules in the air. It's these collisions that create air resistance. This means that for the lighter bikes top speed it will require greater 'perceived effort' to push it through the air.

 

[lulubel]

Because it's more fun to ride a light, fast bike.

 

[Peter Armstrong]

Plus you can go further on the road bike............