at which gear and cadence?

Question

Note: I’m using a set of Shimano 105 50/39/30 crank, combining with a 12-27 (12,13,14,15,16,17,19,21,24,27) cassette.
My friend, Yin drives a 2002 Honda Civic DX, with a 1.7L, 115 horse power engine and a 4-Speed automatic transmission.

Scenario: I’m a very zealous cyclist and enjoy taking on difficult challenges. My friend, Yin and I take the same route to work, which is a quiet rural road. There is a stretch of a six mile straightway (flat side road). She promised to keep her engine below 2500 rpm, which would limit the engine from reaching optimal torque.

So I’m wondering if it is possible to keep up with her car?

If so, at which gear and cadence?

Answer 1

Kate,

I love the way you are always thinking about drafting. Very cool!

Limiting her RPM while accelerating will allow you to keep up with her for a time. Ultimately, though on a flat, straight road, your buddy's Honda is going to get to its highest gear. When she gets to high gear, at 2500RPM, she will probably be going 65+mph.

Drafting a vehicle will allow you to go much faster than otherwise since once you get over 20mph, or so, most of your effort is going to moving yourself through the air. At some point, though, you will not be able to pedal any faster. I tend to find I spin out my bicycle's gearing about 45mph. (I have 53X12 gearing.) Above this, my bottom begins to bounce off the seat and, of course, I don't have the endurance to keep the cadence for long.

You need to work toward developing a super, smooth pedal stroke that allows you to maintain an exceptionally high cadence for a long period. With your bike's 50X12 gearing, I suspect you will spin out your gearing somewhat below 50 mph.

So, let's look at the math.

There are 63,360 inches in a mile. Your 700C wheels have a circumference of about 83 inches. Thus, a mile will require roughly 63360/83 = 763 revolutions of your wheel. In your highest gear, your rear wheel rotates 50/12 = 4.167 revolutions for each revolution of your crank. To go 60 miles per hour, you must be able to crank: 763/4.167 = 183 RPM. That's tough!

To go a more sedate 40mph, you must pedal 122 RPM.

Hope this helps.

Answer 2

Without doing any calculations, there is no way that you will be able to keep up with the car. The six mile straight is the deal breaker. The only possible way for you to be able to keep up would be in traffic.

EDIT: The asker didn't ask about drafting, she asked essentially as if she were "racing" the car... this is how I interpreted the question. If the car driver just went and shifted at 2500 RPM, the car would blow a bicycle away.... the bicycle would have absolutely no chance. Now, if the car driver seriously slowed down and allowed the bicycle to catch up and the like... the asker would have no problem drafting off the car.

Answer 3

What the Blazes is a 4/4 cadence???

A guy further above appears to have done some maths on the subject, I haven't checked if he is correct, cos to be honest with you, I'm not in the mood for it!!!

Ok - you're 'zealous' and competitive, but remember you are on a bike and you're mate is in a car!

Try to develop your riding, without compairing yourself to cars, they are very different and can out 'do you' in many respects - exception being heavy traffic!

Give it a go if you really feel you must - but what are you trying to prove????


.

Answer 4

I agree with the 1st answer. 2500 rpm in a car on a flat strait away with no traffic, the car could accelerate faster than you and reach freeway speed in short order. My car would be going in excess of 75mph at 2500 rpm.

Answer 5

try a 14-24 with a 4/4 cadence.