Sorry for yet another question about compact cranks. Can someone tell me the difference (i.e. benefits or disadvantages) of using compact cranks versus a, say, 27 cassette? FYI, I live in Alaska, so climbing is a major part of riding (and I don’t want a triple).
Thanks!
Todd
I use compact cranks AND a bigger cassette. My combos are 48-34 in the front, and 12-26 in the back. With this, I can ride up long steeper climbs at 15 kph at 90 RPM and still keep my HR under 140 bpm if I want to ride in the hills and keep the ride hilly. I went to a smaller large chainring so that I can basically stay in the large ring for entire races (most of my races are done on rolling courses). With the 48x12, I’m at 60 kph at 110 RPM or so. Any faster than 60 kph and I coast. With the 48x26, I’m down near 20 kph at 80 RPM or so. I’m on 700 wheels.
Personally, I think most bikes are “overgeared” for the average age grouper. We really don’t have the engines to make good use of the 53x (12-15) combos, so all these gears are wasted, which is why I went smaller and now use all gears.
What Paul said 100%. I used to think they were the dumbest thing ever(along with compact frames, and integrated HS)
I have totally converted to the compact cranks and have set up a bunch of MOP and women on the compacts and they love it. If you live and ride in pancake town you might not need the small gears, but in the hilly places they rule. Now I am living my biggest nightmare. I ride a compact bike with compact cranks. At least it has a King headset. If you train alone and aren’t racing, I like the 48/36, or 48/34 set up even better than the 50.
The thing I like most about the 48x34 set up, is that there is also some overlap. I get laughed at by some of my friends who are 56-58 min 40 K TT types, but I have no problem keeping up. I figure that my engine is far in excess of 10% lamer than Lance, so there should be no issue using gearing that is 10% smaller 
Do you guys use the compacts with 650c?
on a slight tangent, I am getting a compact put in this Saturday and I have the choice among various FSA models (I think energy, the megaexo one and possibly a 3rd). Besides not going for the carbon one ($$$) is there any significant difference between the various BBs? Is one better than the other?
I have been looking at gearing calculators and I’m starting to agree that a 48 would work better than a 50, in this case what do you do, do you just buy the 48 chainring separately or are there compacts already with the 48? Is changing the ring something I can do or do I need my lbs to do it?
48x34 on 700s. It would be ~ like 50x36 on 650.
Dev
anyone have problems with the chain rubbing the large chainring. I just got a 50/34 and ride a 12-21. when I’m in the 34-14,13,12 the chain rubs the big ring
when I’m in the big ring I’m at the 21,19,18 cogs. these are pretty bad chain lines.
I’m thinking of using an 11-23 for better lines. what would a 48 chain ring get me?
I have chain rub on the 48 /12 (smallest sproket) only, but don’t normally ride that gear or the big front /big rear cross over either. (old habits die hard because I was told that about 30 years ago I think). Never noticed bad chainline on the 48/19,21,23. I don’t usually in those gears. I seem to use the 34(or 36) 14-25 and the 48 17-12 most of the time. I need to study the charts better and get back with you. I could see (thinking about it) that going smaller in the front could effect chain line/cross over angles. Just not too sure what the answer is. G
I figure that my engine is far in excess of 10% lamer than Lance, so there should be no issue using gearing that is 10% smaller
That’s awsome! Best logic I’ve heard yet.
Kevin
Who’s your LBS? I can’t speak of the different splined bb’s (I’m a tapered square guy myself), but whoever’s doing the job for you ought to be able to provide you with reasons as to why you might choose one over the other.
I went with a Miche compact/bb combo and am quite pleased with it, aside from thinking that the 34 is a little hard to use in the rolling hills. It’s nice to have when I’m slogging up a mountain, but I think I can get by with a 36 and have a better range of gears for general riding. I might not be able to spin up a major climb @ <140bpm like Dev, but I can stand the whole damn thing anyway! 
Deda is apparently now in the compact game as well, and from what I’ve seen, they look pretty sweet.
With the 48 you get excellent chain lines. On the flats I am in the 48x15, 16 and 17 very often. These gears are excellent for cuising around with a nice chainline and when I get the tailwind, I might even drop it to the 14, but rarely the 13 or 12, unless I have solid downhill
my lbs is tri-action, I haven’t yet spoken that much with Greg about this (I’ll go in tomorrow morning) so I’ve been doing some research to be able to actually have a meaningful discussion about it (without everything flying over my head). I think he has only FSA compacts in, so I’ll likely go with one of those.
Climbing is definitely one of my weaknesses (the other two are descending and flats ) so having the 34 for Cypress/Seymour (and Richter) is definitely something I’m looking forward to very much, especially being able to put on a 12-27 when I’m feeling very wussy (as opposed to day-to-day riding which will be a 13-23).
I’m also much more of a spinner than a masher and that’s why (together with the bigger overlap) the 48 route is appealing to me.
I had a FSA Elite PRo Compact on my Kestrel and will have the same on the r2.5. Both are ISIS bb’s previously I have only had (Campag) square taper bb’s, I had to replace one bb in all that time and mileage, and that was three years on my Centaur equipped cross bike. I had to replace the ISIS bb on the Kestrel after 100 miles, looking through old post it seems that for some reason (in ST’ers experience) ISIS bb are prone to failure earlier than other types. My advise would be to spec the highest quality BB you can afford.
Do I take it your are racing at Penticton this year? If so we must met up.
I’ve been reading on things and I think I’ll go with the megaexo bb if at all possible, we’ll see what’s in stock as well.
I am still not sure about IMC, everything was going heavenly till mid-February then I had some major health issues and I’ve been back into training for only about a week: lost TONS of fitness (obviously) so it’s a 50/50 shot, I’m going to try the NB 1/2IM in Victoria and based on that I’ll make the call if I’ll withdraw from IMC or not (it would really suck if I had to but hey, what can you do, it’s not like I could help getting sick).
Ha, my problems started in Mid Nov with excruciating pain in right shoulder when swimming and ended up with severe siatic type pain in Christmas week and my back locking up. Told in mid-fe that I have congenital spondylosis and therefore have lost 4 months of base training! I have a 1/2 IM race Sunday week as the final test to see if I can race at PEnticton.
Good luck in Victoria, when is it?
heh, it seems we both need some good healing vibes
NB is on the 19th so I still have 3 weeks to get ready for the suffering, if I manage to do it without self-destructing on the bike (hilly, that’s one reason why I’m getting the compact, last year I was definitely overgeared) or the run (like last year, where I screwed up the nutrition on the bike) I guess I might manage IMC (although without any sort of time goals obviously).
Good luck for your 1/2, where is it?
A small Victorian seaside town called Weymouth in Dorset. Ever heard of it? It’sa very low key affair of about 250 entrants but is good value for money and only a 40 minute drive from home.
nope, haven’t heard about it, but then I’ve been to England only once so you shouldn’t be surprised (spent 3 weeks in Salisbury with a few day trips to London and the Isle of Wight).
40 min drive sounds quite nice for a 1/2IM!
“spent 3 weeks in Salisbury with a few day trips to London and the Isle of Wight”.
Well, if you lived in Salisbury, you will know Bournemouth and the Bay. I am in Southbourne on the bay 10 minutes jog on the prom from Bournemouth and can see the Isle of Wight from my kitchen window!
“40 min drive sounds quite nice for a 1/2IM!”
Perhaps I shouldn’t add that IMUK is only 50 minutes drive from home.