change to compact gearing

[aqaleigh]

Hi

I have a Boardman 2008 ultegra with 20 speed gearing and 53/39 double

my problem is I want to change the gearing to enable me to do more sportives

The compact gearing suits me fine - so here is my question

WHAT IS THE BEST VALUE FOR MONEY WAY TO CHANGE THE GEARING TO SOMETHING MORE SUITED TO THESE LONGER RIDES (like the compact gear ratio)

answers please

 

[canamrider]

You've got to change the crankset to a compact crankset (50-34 is normal). Lower the FD to fit the 50T big ring. You may need to shorten the chain because your new 50T big ring is smaller than your old 53T. I'm not familiar with Ultegra RD but when I did this on my Campag Chorus set up, I also went to a medium length RD. I'm sure someone else on the forum has had experience with Ultegra as changing from standard crankset to compact is pretty common. It's a pretty straight forward change in my experience.

 

[GrasB]

aqaleigh, You'll almost certainly need to shorten the chain by 4 or 6 links. Then you'll need to work out the BDC of your crankset, if it's 110mm (unlikely) then you can use your existing crankset & just buy a new 34t inner & 50t outer chainring. If it's 130mm then you'll have to buy a new crank set.

As for the rear derailleur, typically a short arm derailleur will have a 29t capacity the typical setup for this is 34/50 chainrings with a 12-25 cassette, however you can use a 12-27 cassette if you have 34/48 or 36/50 chainrings.

 

[jimboalee]

Someone will surely post Mssr Merckx's famous quote.

 

[MacB]

Someone will surely post Mssr Merckx's famous quote.

ah, go on Jimbo, don't keep us in suspense

 

[jimboalee]

I've looked this bike up on the net and got 19.5lb weight.

A 39 x 25 is 42". That's 10" lower than the witchcraft. It should get up a 14% hill. It might get up a 16%.

If it can't, the rider needs to train a bit harder.

 

[MacB]

I've looked this bike up on the net and got 19.5lb weight.

A 39 x 25 is 42". That's 10" lower than the witchcraft. It should get up a 14% hill. It might get up a 16%.

If it can't, the rider needs to train a bit harder.

I quite like a 30" lowest gear and would rather have a bottom end of 20" than a top of 120"

 

[GrasB]

I've looked this bike up on the net and got 19.5lb weight.
A 39 x 25 is 42". That's 10" lower than the witchcraft. It should get up a 14% hill. It might get up a 16%.
If it can't, the rider needs to train a bit harder.

For those who like to drop the inches early & spin? There are a few inclines around here where I can make it up on the middle chainring but it's faster to drop to the bottom & spin.

 

[BJH]

You can't just swap the rings - Shimano do an Ultegra branded compact in the old and new range, or FR700 Compact crank.

 

[jimboalee]

I quite like a 30" lowest gear and would rather have a bottom end of 20" than a top of 120"

It was a subtle way of saying "The bike is designed for a reasonably fit rider to get through a roadrace stage without embarrassment".

There's no need to go swapping to a 'compact'.

If 'spinning' is your thing, get a triple and convert Chris's roadrace bike to a sports bike in one fell swoop.

Someone posted a link on another thread to Tacx turbo trainers' sessions page. The 'Power' session had 50 and 60 rpm intervals. This is NOT spinning, It's training for POWER, which is what's needed on all road bikes.

50 rpm is where you base your climbing ability and power.

 

[GrasB]

You can't just swap the rings - Shimano do an Ultegra branded compact in the old and new range, or FR700 Compact crank.

It really does depend if you have a 110BDC or 130BDC crank or not. I've got 34, 36, 38, 48, 50, 52 & 53t 110BDC chainrings, that gives me lots of flexibility with a 'compact' crank. Shame I decided to go triple in the end .

 

[Randochap]

I'm guess in Jimbo is referring to the Cannibal's famous dictum "Don'y buy upgrades, ride up grades."

But I believe if you need some lower gears for long distance, get 'em. I'll concur with Jimbo that you might as well just get the triple. That way you can get a truly low gear, w/ 30 or smaller inside and no big jumps between rings. I use a nicely spaced 30-40-50. Don't worry about the high; no need for anything over a 50T big ring.

I have a full page on gearing for long-distance @ VeloWeb that discussed the pros and cons of triples vs compact.

 

[adscrim]

What range is on your current cassette? Assuming the bike came with 12-25, why not change to 12-27. The 39/27 ratio is much the same as 36/25 and only slightly longer than 34/25.

 

[jimboalee]

Hi

I have a Boardman 2008 ultegra with 20 speed gearing and 53/39 double

my problem is I want to change the gearing to enable me to do more sportives

The compact gearing suits me fine - so here is my question

WHAT IS THE BEST VALUE FOR MONEY WAY TO CHANGE THE GEARING TO SOMETHING MORE SUITED TO THESE LONGER RIDES (like the compact gear ratio)

answers please

THE best Value For Money way is to train to get that bike up a 20% hill using the gears it's already got.

 

[calvjones]

I'm guess in Jimbo is referring to the Cannibal's famous dictum "Don'y buy upgrades, ride up grades."

.

Given this doesn't translate from French or Flemish, did he ever say it?