IS THIS POSSIBLE?

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montage

God Almighty
Location
Bethlehem
Pushing tin said:
next put larger chain rings on, the higher gears will get you a higher top speed for the same effort


For the same effort? ....surely you can reach a higher top speed for more effort...otherwise everybody would be fitting HUGE gears :biggrin:
 
montage said:
For the same effort? ....surely you can reach a higher top speed for more effort...otherwise everybody would be fitting HUGE gears :biggrin:
Innit.
 
Mountain bikes are slower than road bikes primarily because the riding position is less aerodynamically efficient. At twenty miles an hour on a road bike 80% of your energy is being used just to overcome wind resistance. The remaining drag is split pretty evenly between rolling resistance (tyres and tubes) and mechanical (chain, bearings etc) drag. Anything you can do to reduce your aero drag will make you go faster for the same effort, it's why drop bars exist. Coefficient of drag (Cd) is the combination of frontal area and shape. There is bugger all you can do to significantly change your humanoid shape but you can reduce your frontal area by dropping your bars, by moving your arms inward within the profile of your torso and losing your baggy clothing.

All other things being equal the difference in rolling resistance between a 700c X 24mm and a 26" X 1" tyre is so tiny as to be virtually unmeasureable.
 

Mr Pig

New Member
mickle said:
At twenty miles an hour on a road bike 80% of your energy is being used just to overcome wind resistance.

Years ago I discovered that if I was pedaling down a slope and doing anything over 20mph, if I stopped pedaling and tucked down as small as possible I went just as fast! It's fun rolling past people who are peddling furiously ;0)
 

Cubist

Still wavin'
Location
Ovver 'thill
mickle said:
Mountain bikes are slower than road bikes primarily because the riding position is less aerodynamically efficient. .

And this depends on the type of MTB and the set-up. There are so many generalisations being made that you forget that MTB's are no longer just one genre of bike. Mine is a XC set-up, and my saddle is about three inches higher than the headset. On flat trails it's quick enough, and on road descents it'll do over 40mph. With 80 psi slicks on my 7 mile commute averages about 18mph. The down side is that on technical descents I have to drop the seat or scoot back over the rear wheel to stop the faceplants.
I wouldn't be able to do anything like that on my son's bike, as its geometry is far more upright.
 

Angelfishsolo

A Velocipedian
I 'train' with a triathlete a few days a week and it was very interesting to note that he covered a Ten mile route on an 'ultra lightweight XTR MTB with slicks' faster than he could on his Specialized Comp.
Cubist said:
And this depends on the type of MTB and the set-up. There are so many generalisations being made that you forget that MTB's are no longer just one genre of bike. Mine is a XC set-up, and my saddle is about three inches higher than the headset. On flat trails it's quick enough, and on road descents it'll do over 40mph. With 80 psi slicks on my 7 mile commute averages about 18mph. The down side is that on technical descents I have to drop the seat or scoot back over the rear wheel to stop the faceplants.
I wouldn't be able to do anything like that on my son's bike, as its geometry is far more upright.
 
Location
Rammy
montage said:
For the same effort? ....surely you can reach a higher top speed for more effort...otherwise everybody would be fitting HUGE gears ;)

once you've worked up the gears at the same rate as you would on any bike you'll have a higher top speed due to a higher gearing

road bikes have higher gearing than hybrids and mountain bikes, and it doesn't take more effort to get going and up to speed, yes there is a slight advantage with rolling resistance and weight, but the principal remains.

how often do you use the tiny crawler gear on a mountain bike when on road? so why not get rid of it, make the 32t (middle) the smallest and fit a bigger chain ring on as the third ring?
 
Cubist said:
And this depends on the type of MTB and the set-up. There are so many generalisations being made that you forget that MTB's are no longer just one genre of bike. Mine is a XC set-up, and my saddle is about three inches higher than the headset. On flat trails it's quick enough, and on road descents it'll do over 40mph. With 80 psi slicks on my 7 mile commute averages about 18mph. The down side is that on technical descents I have to drop the seat or scoot back over the rear wheel to stop the faceplants.
I wouldn't be able to do anything like that on my son's bike, as its geometry is far more upright.
Drop the seat?? Poof.
 
Location
Rammy
mickle said:
Drop the seat?? Poof.

some people are fond of their genitalia as it is
 
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