Top speed. Chain rings ?????

[boydj]

How often do you get the chance to reach these speeds and how much time do you actually lose? There's much more time to be gained by improving your speed up the hills.

 

[Doyleyburger]

Agreed !
But I am finding the hills ok which is something I DO NOT want to sacrifice instead of getting better top speed. If there was an option to change the gearing without sacrificing the climbing then I would be up for doing it. Never mind, was just wondering about it

 

[Rob3rt]

Not as aero as the people you are comparing yourself too. At those speeds, aero is everything!

 

[Nigelnaturist]

Well you can change the rear to a 11-25, change the inner ring to a 40th this will give you more range.

 

[AK9]

Is there significant difference to be gained by moving from a 12 to an 11?

 

[HLaB]

IIRC I fitted a SRAM 8spd 11-26t cassette to my Sirrus, in theory that will make you spin out less but as Rob says at high speeds its more about technique and aerodynamics; FWIW, the fastest I've been this year (45.6mph) was on a cyclocross with only a 48t big ring.

 

[Dusty Bin]

Agreed !
But I am finding the hills ok which is something I DO NOT want to sacrifice instead of getting better top speed. If there was an option to change the gearing without sacrificing the climbing then I would be up for doing it. Never mind, was just wondering about it

I'm pretty sure we did this exact same topic a few weeks ago. Did you ever find out what gearing your mates were on? My guess is that it will not be a lot different to yours.

 

[guitarpete247]

 

[Rickshaw Phil]

Is there significant difference to be gained by moving from a 12 to an 11?

By my calculations it'll give approximately 11 gear inches extra at the top end.

 

[Nigelnaturist]

By my calculations it'll give approximately 11 gear inches extra at the top end.

120" is a big gear to push even downhill.

 

[zizou]

When you get to the mid 40s mph there is more speed to be gained from technique and tucking in rather than continuing to pedal.

Is there significant difference to be gained by moving from a 12 to an 11?

It will certainly give you a bigger gear but whether there is anything to be gained from that is debatable. Eddy Merckx and others of his generation were on a max gear of 52x13 it didnt hold them back too much

 

[Paulus]

Moving up to a 53 chainring will increase your top speed a little, but, it will make it a bit harder, as would changing the rear sprocket to an 11. If you have the legs to power along in a 53/11 you need to join a club that specialises in racing.

 

[Rickshaw Phil]

120" is a big gear to push even downhill.

It'll be higher than that. More like 125".

 

[Nigelnaturist]

It'll be higher than that. More like 125".

Sorry I was looking at a 50x11 a 52x11 is 124.33" as you say.

 

[Rickshaw Phil]

Sorry I was looking at a 50x11 a 52x11 is 124.33" as you say.

Either way it's a big old gear and not necessarily the answer.

For @Doyleyburger, gear inches explained here so you know what we're on about.