gearing, roadies vs MTB

[Ty G]

Rookie question here.  I know that MTB gearing is a wider range of gears to give some high and some low while road bikes are geared closer together.  But, what does that mean in the real world?

If I were to grab a road bike and ride it on the same road I generally ride my MTB, would I go faster with less effort?  Would the hills be harder/easier? 

I know the ideal thing would be to find a roadie and see for myself, yet I ain't got one and don't know anyone with one.

Thanks, Ty

[sunset1123]

You would go faster with less effort mainly due to the reduced rolling resistance of the road tires. There are some road groups with surprisingly wide range gearing, and it would be hard to imagine using the lowest gears on a mtb on the road at all.

The real reason road groups are usually closely spaced is to be able to more easily keep a given cadence and adjust the gearing to match the terrain. Changes in steepness are smaller on the road than on a mountain trail, so the gears are closer.

In the real world a mountain bike will be slower on the road, and a road bike will be faster given the same power input. Lots of factors involved in that, but that's it in a nutshell.

[stumpbumper]

Great answer 

There is also the difference in bike weight to consider.  One of my road bikes, a Cervelo R3 with a carbon-fiber frame, weighs 17 pounds versus 27 pounds for my Stumpjumper FSR Comp mountain bike.  As you mentioned, the increased rolling resistance of those wide 26" knobbies versus narrow tires with no tread is a big factor.  In fact, I think it is a much bigger factor than the 10-pound difference in weight between my two bikes.  I say this because I have a LeMond road bike with a steel frame and even though it weighs four pounds more than the carbon bike, my average speed is the same on both and that applies to riding in both mountainous country as well as rolling hills. 

I don't believe the difference in gearing alone between a road bike and a mountain bike has any bearing on speed.  I have another steel-frame road bike rigged up for really brutal climbing but I also occasionally ride it in easier country.  It has a triple chain ring, a 12-34 cassette and a mountain bike derailleur.  In other words, it is geared the same as a mountain bike.  It also weighs the same as my other steel-frame bike and my average speed on it is exactly the same as on the other two road bikes.             

[Ty G]

Cool, thanks for the replies.  Living here in Texas, my only training in distance has to come from riding the wide shoulder of a local highway.  And I was wondering about roadies and speed the other day when a few of them and I crossed pathes.  I rode 30 miles last Sunday and found it very doable with the east Tx hills.    I reckon one would need to find a good balance between speed and mountain for training for things like the routes of Co and the Divide.

[Thumby]

Ty, if you want to put on some miles I would find yourself a road bike, or a cross bike, one that will take up to a 35mm tire.  You can hit any road surface in East TX with that.  11-28 in the rear, and a triple up front would be a bonus.  If you are on the cheap you can find some 1" slicks for the MTB and marvel at your new speed.