Newbie Questions

[eevul]

Hi...first let me introduce myself.

ATM ive been riding for about 3 months now, i took it up as an activity to loose weight. I tried running but the various aches in the knees/shins kinda dictacted that i try something else. Im down from 315 to 247 or so, and loosing. Anyway, when i first started my average speed was 10.5. Today i did a 12.7. The question i have is, the bike im using is a $68 mountain bike from walkmart. Since ive come to enjoy bike riding so much, i will soon be buying a road bike! The question i was wondering about thogh is how much faster will a road bike be? I was entertaining the fantasy of doubling my speed, but i know thats not going to happen, but what can i expect, if anything?

Thx!

M

 

[Sprinter_989]

You will be flying compared to a mountain bike. If your really enjoying riding I would strongly suggest getting a road bike. You will get faster and faster with each ride

 

[lostmyshape]

well... eventually you could double that speed, but don't expect that right away... if you get a decent road bike you will see a couple mph increase for sure!

more than that, you'll feel like you're going a lot faster. the best difference (i think) is that it feels like it takes a lot less effort to accelerate... which is fun... and going downhill... you'll love it! better than more speed, i expect you'll get more satisfaction out of a faster, more resposive bike.

and if you stick with it, those goals of 22-24mph ARE reachable.

have fun!

 

[kmurnane]

Originally posted by eevul
Hi...first let me introduce myself.

ATM ive been riding for about 3 months now, i took it up as an activity to loose weight. I tried running but the various aches in the knees/shins kinda dictacted that i try something else. Im down from 315 to 247 or so, and loosing. Anyway, when i first started my average speed was 10.5. Today i did a 12.7. The question i have is, the bike im using is a $68 mountain bike from walkmart. Since ive come to enjoy bike riding so much, i will soon be buying a road bike! The question i was wondering about thogh is how much faster will a road bike be? I was entertaining the fantasy of doubling my speed, but i know thats not going to happen, but what can i expect, if anything?

Thx!

M

Eevul, there’s good news and bad news. Based on the belief that it’s better to have a realistic outlook than to be expecting too much and end up disappointed and discouraged, here’s the bad news first. - you’re not going to go as fast as you would like, at least not for a while anyway. Look at the physics. As your velocity increases, rolling and mechanical resistance increase linearly at a fairly gentle slope. Air resistance, on the other hand increases exponentially with the *cube* of velocity. Yikes! That means several things. First, fast cycling is all about overcoming air resistance. At about 12 mph half the effort you are putting out is being used to overcome air resistance and half is being used to overcome mechanical and rolling resistance. By about 20 mph approximately 80% of the effort you are putting out is being used to overcome air resistance. Note that these speed and effort points will vary depending on factors like the size of the rider and the position you’re riding in. The bigger you are and the more upright you are the worse it is. Second, after a point the faster you go, it becomes increasingly harder to go even faster. It is much harder to increase your speed from 16 to 17 mph than it is to increase from 15 to 16 mph. Likewise, it even harder to go from 17 mph to 18 mph than it was to go from 16 mph to 17 mph. And it keeps getting worse. Doubling posted best of 12.7 mph gives 25.4 mph. The pros in the peloton of major stage races like the Tour de France ride about this speed. On a ride of any appreciable length you are unlikely to ever ride this fast. Right now you are the point where mechanical/rolling and air resistance are roughly equal. It’s going to get progressively harder to go faster from here on although it’s still pretty easy up to about 15 or 16 mph.

Now for the good news. Your road bike will probably be much lighter than your mountain bike. This will make a big difference, especially on hills. If you do any hill climbing the benefits of the lighter bike will be immediately apparent to you. Another benefit is that mountain bikes are all wrong for speed riding. The upright position means you catch a lot of wind which will slow you down immensely. Also, the position of your seat relative to the pedals puts you in a position that is far from ideal with regard to generating the power you need to go fast. On a road bike your body is in a much better position to put power into the crank. Since you have trained thus far on a mountain bike there will be a changeover period where you will be bringing new muscles into play which will make it seem harder. Don’t get discouraged, your legs will get stronger in the new position and your speed will increase. There are a lot of other advantages to a road bike as well such as more positions for your hands on the bars to reduce fatigue and numbness in the hands and a much more comfortable position for longer rides of several hours.

You wrote that you’ve come to enjoy riding a lot. That’s all it takes, really. If you love to ride you will continue to ride. Your speed will go up, your weight will continue to come down and you will have a terrific time. You’re not going to go as fast as you’d hoped on the new road bike but you’re going to go fast and more important, you’re going to love it.

--Kevin

 

[jhuskey]

First off a Wal-Mart bike has crappy components and weighs a ton. A good road bike will shift better and respond better. Changing the tire from big off road tires to high pressure tires will increase your speed at least two mph. I know this from experience. You can coast downhill on a road bike about as fast as you can pedal a mountain bike. You may however find yourself expending just as much energy without realizing it but will be achieving faster speeds.Stay with it, set goals but enjoy the scenery along the way.