Low gear and speed.

[ray316]

I've been watching Tour de France and now watching ride London on T.V.
One thing that I cannot understand and I'm sure someone will answer is the gears they use on flat grounds and speeds they get up to using them.
A lot of the cyclists seem to be using the big ring on the front and low gears 1 to 3 on the back and get some real speeds on these gears.
Now I use these gears a lot on flat grounds and I am peddling at a high cadence but don't get anywhere near the speeds they do.
The cyclists on T.V don't seem to be peddling as fast as I am but getting better speeds,
How do they do this , am I missing something here..

 

[13 rider]

Pros tend to ride with bigger chain ring on the front 53/39 compared to most peoples compacts 50/36 only three teeth but it makes a difference . Am they may be a bit fitted

 

[Racing roadkill]

It's about the range of ratios they have available. Big rings, and bespoke cassettes.

 

[Citius]

Very few - if any - 'bespoke' cassettes around. OP - what bike are you riding and what gearing?

 

[potsy]

How long before somebody recommends the OP upgrading their wheels?

 

[User269]

Pros tend to ride with bigger chain ring on the front 53/39 compared to most peoples compacts 50/36 only three teeth but it makes a difference . Am they may be a bit fitted

54x42 more like. Oh, and the OP should upgrade their wheels.

 

[Racing roadkill]

54x42 more like. Oh, and the OP should upgrade their wheels.

With a Brompton wheel on the back, and a 32t big sprocket.

 

[mjr]

A lot of the cyclists seem to be using the big ring on the front and low gears 1 to 3 on the back and get some real speeds on these gears.

Are you sure they're in 1 to 3 on the back? I must admit, I've not been ogling the sprockets during the coverage.

Besides that, I agree with the above: the chainrings typically supplied on modern retail bikes aren't the current popular choices in races... Once upon a time, mass-market retail bikes were closer matches to what racers used. Readers of "Classic and Vintage" forum will know I've acquired a couple of 1980s bikes recently and the 10-speed came with a reasonable-ish 40-102" gearing, but the 3-speed also had 100+" top gear which left the bottom gear as a kneepopping 57"!

 

[mjr]

Are you sure they're in 1 to 3 on the back? I must admit, I've not been ogling the sprockets during the coverage.

Just did a bit of maths and actually, even if they were using typical 52+42 on the front and one of Shimano's higher-geared standard 11-speed cassettes on the back (which is reasonable as the Surrey hills aren't really mountains), then the third-smallest would be 21 teeth, giving roughly 27"x52/21=67" which seems a reasonable gear on the flat, giving 20mph at 100rpm cadence. (I know that's only rough because the wheels aren't 27" any more...)

 

[bpsmith]

19.5mph if they are using 700 x 25C tyres.