Hey. I read the article here on slowtwitch about the gearings between the 53/39 and 50/34 cranksets. It looks like I may be better served by making the jump to the compact crank. I’m currently on a 53/39x12/25 and would think about the 50/34x11/23. They seem pretty similar but the compact would give a little wider gear range at the expense of a slight increase in gear spacing. I don’t really see that I’ll be in the market for a gear as large as the 53x11 for a while, so that’s why I was thinking that maybe the CC was a good option for me. The other option is to just ride what I’ve got and stop all this obsessive nonsense .
At any rate, and all that was long-winded just to ask, what would I need to actually get this drivetrain running on my bike? I’m currently on a TREK 5200 with 9spd Ultegra with 53/39x12/25. Will my current FD work? Would it sit too high with the smaler chainrings? What different chainring options do I have? So how about 2 scenarios
Keep 9 speed upgrading to CC
Switch to 10 spd while upgrading to CC
Thanks so much. I just didn’t want to get too deep into this only to realize that it was going to be a pain to make it happen.
Sort of depends on where you live…mountains, good idea…midwest…bad idea (or just not needed). I think the best way to look at a compact is if you do, or dont need a triple.
I am no teech weeny and there is a good argument to just stay with what you have but…
I own a 5200 triple, a Trek 5.9 compact and a P3 53/39, so I have really compared. I live on the coast where our only hills are bridges but I have a little condo in the NC mountains where I ride once a month or so (and where I leave the triple). I am spoiled to have the three bikes, but if I had one it would be the compact. I bought the 5.9 about 6 months ago. Shop tried to talk me into the compact, but like most others nay-sayers, I wanted no part of it, plus I liked the looks of the new dura ace. Then I signed up for a very hilly Three-Mountain ride and could not get to my triple. I blew the money to buy a 50/34 and a 12-27 and put them on the 5.9 for the ride. The 27 was rough, but ignoring that it worked great. I was so satisfied, that I left the compact on the 5.9 (moved new dura ace to the P3) with an 11-25. Shifting is not quite as smooth, but I am, otherwise, a total convert (FYI-I am 46 and don’t push a big gear). I think the big winners will come when the compacts filter down to the less expensive market where people generally don’t change out gear.
I recently did this on my tri bike for IMLP. Had Ultegra 9 speed with 12-25. Switched the crank to the FSA SLK Mega Exo compact 50-34. Had to take one link out of the chain, (and replaced the chain while I was at it) but other than that used everything else. You’ll just need to lower the front dr a bit.
I was even able to do it myself after going through the Park Tool School at my LBS last winter.
Yes, your front der. will work. You might have to lower is down a bit, or you might not. There isn’t a big difference in diameter between a 50 and 53.
Not sure why you said you’d get wider gear spacing on the compact. I thought it was tighter with less overlap and wider range. What am I missing. What I really like about the 50 is that you spend more time in the 12,13,14,15 range with tight spacing instead of the 14,15,17,19 you’d have with the 53 and 12-25.
I don’t understand the argument against compact if you live in flat areas/midwest. 50/11 is taller than a 53/12 and 34/23 is smaller than 39/25, so what exactly are you giving up??? Oh, that’s right… Nothing.
Unless you regularly ride at over 30 mph, in which case you might run a 53/11 why would any mortal cyclist use a 53/39 up front? That setup is practically obsolete for anyone paying attention. Do the math, 50/11 at 100 rpm is right near 35 mph.
Let’s review: Compact with an 11/23 gets your a wider range than a 53/39 and 12/25 Compact gearing gives less overlap Compact gearing gives you tighter spacing between gears thanks to the 11/23 or even 11/21 if you like Compact gearing gives you the option of running a 12/25 for the gnarly rides Compact gearing weighs slightly less
Isn’t the above true? And the cons are???
P.S. I’m entirely not interested in the one or two CAT 3 cyclist who do Time Trials, but don’t race triathlons that insist compact gearing is too small for them. Yeah, so? My comments are directed towards triathletes.
Yeah, that was my thought exactly. I couldn’t really see a scenario where I’d need the 53x11 very much, but having the increased lower and upper ends on the compact vs the standard 12x25 I’m running now seemed appealing. Mainly I was just wondering technically if I was getting into too much wrenching or if I could just slap some new cranks and cassette on there and go.
Live in Piedmont NC and ride in the mountains about 3 -4 times per month. I went from a 53/39 with a large of 26 on back to a 50/34 with a 25 large and it has made a world of difference. If you ride any significant hills (read 1-2 miles or longer) then a compact is a great idea. Alot of the Cat 1,2, & 3s around here have gone to the compact with an 11 in back. Hope this helps.
I just wanted to add to the pros of the compact crankset…
You’re not limited to running a 50/34. Some compact cranks are sold as 50/36 or 52/36. You can find small rings from 34-46 and big rings from 40-53+.
I’m I understanding all this correctly. My tri bike is a 53/39 with a 11/23 in the back. From what I’ve be reading, I’m thinking that all I have to do is buy the 34 to get the same thing as a compact crank. Is that all there is to it? It sounds like you need to adjust the derailler and maybe the chain. I thought for some reason you had to buy everything together.
From what I’ve be reading, I’m thinking that all I have to do is buy the 34 to get the same thing as a compact crank. Is that all there is to it?
No, there’s more to it than that. You’ll notice that compact cranks (and more and more standard cranks) give you a BCD size. This is the ‘spider size’, or the size (diameter?) of the drive side crank arm that actually attaches to the rings. Standard and Compact BCD sizes differ from manufacturer to manufacturer, I know for a fact that Campy Compact is a different size than FSA. If you don’t get the right BCD size ring, it won’t fit the crank spider. So, you need to make sure that the rings you’re looking for come in the right BCD size.
Next, there’s the issue of the maximum number of teeth difference between the ‘big’ ring and ‘little’ ring (relatively speaking) that the derailleur can handle. If you are able to find a 34 tooth ring in a standard BCD size, I don’t think your derailleur will be able to shift it…now I know a few people here will say “well, it’s all friction so I’ll muscle it over”…good luck, you’ll be replacing your chain FREQUENTLY, and probably the derailleur too.
So, need more than just a smaller ‘small’ ring. At the least, if you can find the rings in the right BCD size you’ll need both to avoid the maximum tooth difference issue (I know there’s a technical term for it, just can’t remember it right now). If not, you’ll need a new compact crank and adjust the derailleur.
