Higher gears with a compact

DavidJB

Hello,

I have a compact ultegra crank, trouble is I am doing time trials on it and tend to start spinning out if theres a downhill.

Is there anyway to get higher gears on the cheap without changing my crank?

Thanks

explosifpete

change to a cassette to one with an 11 tooth cog, what ratio cassette do you run atm?

rafletcher

If you're intending to keep TT'ing a compact is not the way to go. Replace it with a standard double as soon as. Apart from lifting the front mech higher, (and maybe adjusting limits) possibly fitting a longer front mech cable, and fitting a longer chain it's a straight swap.

Oh, and it's higher gears you want, not lower

explosifpete

if you change the cassette you just need to change the cassette.
also a 53 chainring with a 12t cassette (standard for most bikes) is a lower gear than a 50t (compact) running with a 11t

schweiz

As explosifpete says:

50/11 = 4.54

53/12 = 4.41

53/11 = 4.81

Also, to achieve 45 mph with 700C wheels:

50/11 = 125.6 rpm

53/11 = 118.5 rpm

You just need to learn to pedal faster. If you can spin at 118 then it's not much to get your legs going to 125.

DavidJB

Thanks all, the season is nearly over now and I'm thinking about getting a dedicated TT bike anyway...but the Mrs wants a house so not really time for new bikes Looks like a crank change is the best option!

If I change the crank I assume I can just use it with my current rear cassette?

Monty Dog

Very few TT courses require anything but the big chainring - running an 11-23 cassette with a 50 tooth chainring is going to be more useful that a 53 chainset and a 12-25. When you say 'spinning out' you probably mean 90+ rpm and you just need to learn to pedal faster.

markos1963

No need to buy a new crankset, Stronglight do a range of front rings with a BCD of 110mm.
Mind you very few testers would need big chainrings, just use a 11t cassette and spin harder.

rake

3+
you have no talent, go and learn how to pedal.

nmcgann

Monty Dog wrote:

Very few TT courses require anything but the big chainring - running an 11-23 cassette with a 50 tooth chainring is going to be more useful that a 53 chainset and a 12-25. When you say 'spinning out' you probably mean 90+ rpm and you just need to learn to pedal faster.

This is not practically possible for some people when they are racing at the limit of their power output. I count myself among them - power tails off over 90rpm and no amount of training has ever changed that.

markos1963

nmcgann wrote:

Monty Dog wrote:

Very few TT courses require anything but the big chainring - running an 11-23 cassette with a 50 tooth chainring is going to be more useful that a 53 chainset and a 12-25. When you say 'spinning out' you probably mean 90+ rpm and you just need to learn to pedal faster.

This is not practically possible for some people when they are racing at the limit of their power output. I count myself among them - power tails off over 90rpm and no amount of training has ever changed that.

Yes but the OP hasn't mentioned a figure for 'spinning out' he could be talking about 70rpm! Even on a 50/12 he would be doing well over 35mph before 'really' needing to worry and how many TT'rs do you know manage that? Not even the mighty 'Hutch' can.

rafletcher

rake wrote:

3+
you have no talent, go and learn how to pedal.

Very helpful - not.

You can 9as many TT'ers do) fit bigger front chainrings that 53, as has been suggested above. I don't know the max ring size that is available for a compcat though - but someone else will!

markos1963

rafletcher wrote:

rake wrote:

3+
you have no talent, go and learn how to pedal.

Very helpful - not.

You can 9as many TT'ers do) fit bigger front chainrings that 53, as has been suggested above. I don't know the max ring size that is available for a compcat though - but someone else will!

I got these on my TT rig(although I use a standard double and a 55t) very smooth running. You would have to fit a 39 or 42 inner as the jump from a 34 would be too big for the front mech.
http://www.spacycles.co.uk/products.php ... 0s149p1120

I only use the big ring because in race mode I can keep a straight chainline whilst riding, not because I can spin out on my compact that I previously used.