changing from a 52/36 and 11/25 to compact 50/34 11/28
 

I did a search, probably didn't word it right but had no luck in finding an answer tho I'm sure it's been discussed ad nauseum.

Is it possible to convert my R5 to the same gearing as on my Roubaix. I ride lots of rolling hills and the Roubaix seems to work much better for me, I find myself leaving the R5 at home most of the time.

THe R5 has 52/36 and 11/25 which I believe is called semi-compact. the S-works Roubaix has 50/34 and 11/28 which is compact.

So is this an easy change? I would guess besides the cassette and chain rings you'd also need a new chain?

Thansk!
Chris,

Again sorry I couldn't find in a search but I tend to be inept at wording searches! :)

Should be an easy change; IF your rear derailleur (RD) can handle a 28T cog.

The 36T ring indicates that you most likely have 110mm BCD cranks, so you just need to purchase a new 50T ring. For now, I would recommend trying the 50/36 combination with 11/28 cassette.

Going down two teeth on the big ring, if the chain is newish, I would leave it when trying on the 11-28 (if you could get a 11-27 or 12-27, so much the better - as the total tooth count is the same 52+25 = 50+27). You may find you like 50/36 better than 50/34. On one of my bikes I went from 50/34 to 50/38 - much less stress on the knees when shifting front rings.

+1, 2 teeth on a 52 ring is less than 4% change; also agree that a 12-tooth small cog is more useful than 11, or at least should give an additional useful cog in the middle.

As long as your rear derailleur will accommodate a 28t cog you should be fine. You will likely have to move your FD down. You may or may not need a new chain.

Just get a 12-27 cassette and save your money.
You'll get about the "desired" gearing and not have to mess with the front rings/DER.
50-50 chance you'll need a longer chain.

That all depends if the "desired" gearing is a granny gear for hills. 34-28 is a lot easier on the legs uphill than 36-27 in my experience.

Rather than approxiamting or doing mental calculations, here's a calculator which makes it easy to compare two sets of gearing choices: kstoerz.com | visual drivetrain comparison tool

OP stated "...I ride lots of rolling hills and the Roubaix seems to work much better for me..."
OP didn't state he has a difficult time getting up the hill(s).
My suggestion will seem to work better too and is a hell of a lot cheaper.

thanks everyone for all the very useful info! I opted to let the bike shop change out to the 50/34 and 11/28 so my r5 will be geared just like the roubaix. For the predominant roads I ride, rollers, the compact gearing is much better. I found myself seldom riding the cervelo because of it. Hoping to get it back. Since I've got around2500 miles on the chain, rings and cassette I went ahead and opted for new parts. Probably overkill but way I wanted to do it.

Chris

Don't look back. You did what you were comfortable with. Now get out there and enjoy your season

Put 150 miles on it this week, so glad I made the change, now I'm actually happy to get out on it!

My previous bike has a triple 52/43/30 and my new bike has a compact 50/34 11t-28t. I am happy with the 34 on the new bike but cant seem to get use to the 50. Feels like I am peddling too much and not moving enough but when I change gear, it seems too hard. I feel like I need a gear in between. I am now considering changing to the semi-compact 52 on the new bike.

a lot depends on what type roads you're on. I ride on a lot of moderate sized rollers and I just never like 52/36 on the R5, rode it again last nite and love the change. I'm going to have the pinarello I ordered which comes semi-compact to compact.

The most important 6" in cycling is between the riders ears, if that 6" is happy the whole rest of the mess comes around hehe.

Bill