newbie question

[john74]

im a bit confused about use of gears. I come from a mtb background and have been bitten by the road bug but im slightly confused about use of gears on the road for example. I did a 40 mile loop using only my middle chainring 39t (triple chainset) then the following day i did the same 40 mile loop using only my large chainring 53t.
The first ride i got home and i was sweating rather alot but my legs felt fresh.
The second ride i was hardly breaking a sweat but my legs were done in and average speed was only 1.75mph up on the previous ride.
So my question is what is the correct system to use?

[Feline]

Personally I make full use of both front and rear derailleur and use all of my 30 gears on most rides  

Someone will be along in a minute to tell you that you only actually need 1 gear!

[mattc]

Hi John,

Why don't you use your gears the same way you do off-road? (I presume that you don't ride at a constant speed off-road OR on-road!).

Or for that matter, how do you ride the MTB on tarmac?

Matt

[bobb]

If you're using a geared bike you should be aiming to keep your cadence as constant as possible - I guess that's what gears are for! Most n00bs push way too big a gear with a very slow cadence - but you're not a total n00b if you've come from mtb. I believe a fast cadence is more efficient muscle wise, but you need the aerobic fitness to keep it up.

[john74]

I dont think i would ride fast enough to spin out on a 39x11.

on the mtb im a bit lazy middle ring for off road unless really tough.
large ring for road.
i have strong legs but my lactate threshold doesnt seem that high.

cadence in the big ring about 60rpm
cadence in middle about 90-100rpm

[john74]

Thanks bobb thats sort of what i was wondering  about efficiency but i dont think i explained the question very well.

[MSeries]

If you're using a geared bike you should be aiming to keep your cadence as constant as possible - I guess that's what gears are for! Most n00bs push way too big a gear with a very slow cadence - but you're not a total n00b if you've come from mtb. I believe a fast cadence is more efficient muscle wise, but you need the aerobic fitness to keep it up.

 92rpm apparantly

[Alouicious]

I dont think i would ride fast enough to spin out on a 39x11.

on the mtb im a bit lazy middle ring for off road unless really tough.
large ring for road.
i have strong legs but my lactate threshold doesnt seem that high.

cadence in the big ring about 60rpm
cadence in middle about 90-100rpm

You shouldn't be using 39 x 11 on a triple.

There will be a 53 x X that will be of similar development ( or inch length in the old money ).

Draw up a table on a spreadsheet of ring vs sprocket. The sum is ( ring / sprocket ) x 27 for inch gear length. You will notice 'overlaps' where small to small and large to large are redundant. Also middle ring to smallest and middle ring to largest will be redundant.

You will need to ride round loads to find what pedaling speed ( cadence ) suits you. This is not a waste of time because the further you ride, the more muscle conditioning you do.

Don't be fooled by only riding for twenty five miles. This distance is only a 'warm-up' and after this distance, your legs should be humming.

[vorsprung]

If you want to feel fresh use a smaller gear and spin faster
If you want to go a bit faster use a bigger gear

Going 1.75mph faster is quite a bit faster maybe that is what made you "done in"

But surely you know that anyway, MTB work like that too, it's not road bike specific

[Alouicious]

If you want to keep the same speed in whatever gear you choose, you must produce the power for it.

If you want to feel less exhausted, tuck down with your hands on the drops and bend your arms to get your chest near horizontal. This way, you'll have to shift less air to go the same speed, so power requirement will lessen. Also this way, you can ride faster for no increase in power input to the rear hub.

That's what the lower part of the handlebars are for.

1.75 mph increase with relation to what? If its a 10% increase, you were needing to produce a 20% increase in power. No wonder you got knackered.