rolling resistance

[oberun]

Hello. I am about to buy my first road bike. I went to the store today and sat on the one I want. (I'd say what it is but you would all laugh) I was just wondering just how much of a difference it will make going from a mountain bike to a road bike for my 15 mile ride to and from work. Also does spandex make a big difference? Thank you.

 

[ABG]

Hello. I am about to buy my first road bike. I went to the store today and sat on the one I want. (I'd say what it is but you would all laugh) I was just wondering just how much of a difference it will make going from a mountain bike to a road bike for my 15 mile ride to and from work. Also does spandex make a big difference? Thank you.

Well getting skinny, "slick tread" tires - on the order of 20 mm - 28 mm - will actually make you go a bit faster. I doubted this when I was first told that replacing my 45 mm tires with 25 mm ones would actually make me go faster, but it really does. I find myself frequently in somewhat higher gears. Or maybe it was just a placebo effect.

Mountain bikes are usually heavier than road bikes. I think the average mountain bike is 35-40 pounds, whereas the average road bike is about 25 pounds. Expensive ones are 20 pounds and less, even. So that'll make a difference too.

Now the only thing is, are you OK with the drop handlebars?

 

[Phill P]

My girl friend didn't believe me that going from a MTB (which had slicks) to a road bike would make a big difference........but I was proved right (again.....)

Aero dynamics and rolling resistance of road wheels is vastly better. The high pressure tyres make getting upto 30kph (19mph) a breeze for a fit cyclist, and the extra aero advantage of less frontal area, and in most cases less spokes, means pushing on past that point to higher speeds becomes viable.

If you look at places in north western europe you'll see most people ride 700C wheels on thier commuter bikes. If it wasn't smoother and faster everybody would have changes decades ago.

MTBs have smaller diameter wheels for handling and weight advantages (for a given tread). However there is a growing fashion for 700c or 29" MTBs which suit some trails and conditions (ie not too much braking and accelerating on bumpy but not wheel destroying trails).

 

[oberun]

I thought the drop handles were low. It was more of shock than anything, but I think I am going to like it alot though. I usually ride like I had those nifty time trial handles. I I get about 20mph average on my current bike. (Motiv cross creek) And the bike I want does have the 700c tires. I think I will love it. Thanks

 

[Archibald]

i average a casual 20-24kmh on the mtb when commuting, compared to 30+ on the road bike.
i find that my cadence is much higher on the road bike too for some reason when i'm feeling comfortable in the ride.

 

[gclark8]

i average a casual 20-24kmh on the mtb when commuting, compared to 30+ on the road bike.
i find that my cadence is much higher on the road bike too for some reason when i'm feeling comfortable in the ride.

Two things, measure the crank lengths, the MTB will be longer. Check seat tube angles, the Road Bike will be steeper. Two reasons for higher cadence and easier pedaling.

 

[mikesbytes]

There are a number of reasons that a road bike is quicker than a road equiped mountain bike and each one of them adds a little to the overall result. One that many seem to overlook is wind resistence and the biggest object on the bike is the rider and hence why road bike riders are hunched over to provide lower wind resistence. The more upright position on a mountain bike is designed to give the rider maximum control on off road surfaces and aerodynamics is not particully important off road, unless you are a manic.

In regards to the tyres, the rolling resistence is largely dependent on the air pressure and skinner tyres do not give less rolling resistence than fatter tyres of the same construction. Often quality road bike tyres are being compared with lower quality mountain bike road tyres which isn't a fair compairsion. A top quality mountain bike road tyre will actually have less rolling resistance than the equivilant road bike tyre as it will be wider. However the skinner road bike tyre wins because a skinner tyre has better aerodynamics.

Anyway forget the science and enjoy riding your bike.

 

[oberun]

Nah I love the science. I thought that wind resistance was a big thing since I am akways hunched over anyway. I can't stand to ride sitting up on my bike. I just lean on the handlebars with my hands over the front tire. Thanks again guys.

 

[DiabloScott]

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Hey, my dog's name is Oberon!

 

[mikesbytes]

Hey, my dog's name is Oberon!

Hey Diablo, Isn't it the middle of the night in the US? I'm just back from the Saturday morning ride, but we are about 3/4 of a day ahead of the US.