J_Climacus

I'm sorry for the title typo it should be 52/39 and 12-23. and Tl;Dr: will I run into any functionality problems (shifting issues, etc) by using a 52/39 crank with a 12-23 cassette?

I am building a bike with 9 speed campagnolo parts. The parts are off someone else's bike, and the sprocket sizes on the crank are not standard for what the crank set was designed for. It is a 52/39 crank but the big ring indicates it is supposed to be paired as 52/42. It has a 12-23 cassette. What I want to know is: is this crank set and cassette functionally pairable? Will I run into anything like shifting problems by using this pairing?
​​​​
Thank you in advance for the help. I think this is probably a dumb question but I can't find the answer and I really have spent a long time looking. I also tried Sheldon's calculator but I don't understand what it's telling me. And every piece of research I find is asking if a given gear ratio is good for *riding* but I just want to make sure my combination is functionally compatible. I am a casual rider and definitely not a racer so I feel confident I can make whatever gearing I have work for me.

CliffordK

It should be fine. Obviously the front derailleur height will have to be set to the crankset, and the rear derailleur body tension screws will have to be adjusted.

You'll need some power for steep hill climbs. Not impossible for many cyclists, but not comfortable for some. Standing hill climbs?

3alarmer 

.
...depending on what front derailleur you choose to use, most of them will accomplish this shift. The very old ones will have more trouble with it. 12-23 in a 9 speed cassette is more of a race gearing. AS a casual rider you are probably better off with something wider in ratio. But if that's what you have already, and don't want to buy another one, it ought to work. Make certain that the chain rings on the crank will fit into the narrower 9 speed chain.

J_Climacus

It's all campagnolo record 9 speed. The second generation - shifters are 1998 and derailleurs, from the look of them, are 98-99 or thereabouts. When you say something wider, is there a specific 9s cassette range I should be looking for as a casual rider on a 52/39 to make the shifts compatable and smooth? I would prefer a casual well rounded gearing - not race oriented. The initial research I'd done had led me to believe the cassette wasn't too crazy but maybe I was wrong.

tFUnK

Pretty standard gearing for race bikes back in the day. The pros probably still run this for flat stages.

cxwrench

You're fine. It will work great. No need to change a thing. Most cranks with a 39 also had a 53. Most 52t rings are 110 BCD not 135...is that 52 actually a Campy ring? No need to look at different cassettes, the close range gearing will always shift better than wider range. Don't overthink this, your bike will shift very well.

J_Climacus

Thank you so much for taking the time to respond with this. Very reassuring and exactly what I needed to hear. Thank you!

FBinNY 

The ONLY issue MIGHT be smoothness on front shifts.

The shift gate on the outer ring is phased to lift or drop the chain best with the companion 42t inner. So, unless you're lucky, the shifting will be a bit less than ideal.

How much worse is unpredictable, and you won't know until you try. If you are unhappy with it you can try rotating the inner ring one mounting bolt position, and repeat until you find the one that shifts best.

However, the worst case isn't that bad, so there's no reason not to go ahead.

Hondo6

FWIW: 52/42 was a pretty common front chainring combo with various different BCDs in the 1980s and before. In particular, as I recall it was a standard Sugino and Shimano combo for 130mm BCD.

Also FWIW, Campagnolo did at one time make 52T chainrings in 135mm BCD. Not sure if they still do or not.

maddog34

i put about 20K miles on a 53/39 setup... 12-23 then 12-27 on the rear wheel.... still working fine.

J_Climacus

Yes, it is actually a campy ring. I can't post a photo because I don't have enough posts yet, but both chainrings clearly say campagnolo. The inner does have a slightly different silver color, however.

cxwrench

Doesn't matter. Just ride it.

SJX426 

The Racing T, 9 speed all, are 52/42/30 or 50/40/30. first two on a 135 BCD. I have considered replacing the 52 with a 53 because my rear is 13-26 and 52/13 is a bit short down hill.
At the same time, I have a 10V Ergo so am considering just replacing the cassette with 12-25 10v.
P1050228 on Flickr

Kapusta

Rear shifting will be fine. I’ll defer to others on the front. Gearing range will depend on the rider and where they ride. 39/23 low gear is way too high for me where I ride, but might work for you where you ride.

J_Climacus

I found a copy of the old 1998 campagnolo catalog (can't link due to 10 post rule), and it appears as if this was actually a standard ratio offering by Campagnolo. I am not sure if it was the 52 or the 39 that ended up being replaced at some point, but I at least feel good knowing that this was "normal"! I have probably a lot of time in front of me since the bike this will go on is with a framebuilder to do some repair and respacing of the rear triangle, so I may still look for a different crankset, but now it would only be because the new one I could find would be in better condition and *not* because I was worried about compatibility issues.

Thanks again for everyone's help!

alcjphil

Campagnolo over the years has offered 52/39 chainrings often. I have an Ultra Torque 52/39 10 speed crank that I bought years ago as an upgrade. In fact, I bought 2 of them as Campagnolo was clearing them out at bargain basement prices. I have since moved on to compact cranks which I now need since I am no longer as strong as I once was. I gave one of them to my son and have the other one in my storage room

rm -rf

Front shifting
I think that most 9,10,11 speed cranksets have specific grooves and pickup rivet pins on the big ring to make the shift to the big ring quicker and easier with the two original matched chainrings -- the locations of the grooves and pins are supposed to work best with that specific small chainring. I'm guessing that other non-standard combos are reasonably good, though.

Gearing
That gearing is perfect for fast riding on fairly flat roads. But it will be difficult on steeper climbs.

At a low 50 rpm: the 39F-23R lowest gear is 6.5 mph.
At that 50 rpm: A more modern 34F-28R is 4.7 mph.
That 34-28 is 28% easier, about 3 rear shifts.

(Most riders I know, including me, have a low gear of 34F - 32R. at 50 rpm: just 4.1 mph. A huge 37% easier. My group "likes" hills now!)

~~~~
From Mike Sherman's gear calculator. Link to this 39-52 and 12-23 setup.

Speed ranges of each gear combination for a typical flat road cadence range. The big chainring in black, small chainring in red.
How to read this chart: see the black bar labeled "19", that's the 52 chainring and the 19 cog -- at 82 rpm, it's about 17mph. At 95 rpm, it's at 20 mph. It's useful to see how the gear ranges overlap.




~~~

compare to my 11-speed 34-50 and 11-32 at the same cadence range. a wider cassette range and more usable gearing at lower speeds. Fewer shifts within the 20-25 mph range, though. If I'm going over 20mph, I'm maxed out and trying to find the exact cadence I want, shifting up and down to pick it.

cxwrench

Did you bother to read the OP's very first post? I've bolded the parts you obviously didn't pay attention to. Your reply w/ all that information and those visuals is great, but it's not what the OP was looking for.

J_Climacus

To be fair, they did answer that stuff in the beginning of their post, and I did find the other extra context helpful, even if it wasn't what I explicitly asked for. For over a decade now my bike has been either a fixed gear or an old 6-speed with a single chainring up front, so having a 9x2 will be a totally new experience for me. Part of the reason I assumed I could make any gear range work is that, well, if I have only had 6 speeds and been making it work, surely I will find some gears that work when I have 18! But I did find this writeup to be helpful and I appreciate the time that was taken to write it.

redshift1

I'm sorry for the title typo it should be 52/39 and 12-23. and Tl;Dr: will I run into any functionality problems (shifting issues, etc) by using a 52/39 crank with a 12-23 cassette?

I run this gearing in my 90's Cadex alum. frame ( I'm using 8-speed ) and have for years, and with the number of cassettes I have, it looks like I will be running it for many more years....

Shifting is no problem and the only issue that may concern you is hill-climbing. My friends use what look like granny gears to me in their cassettes. It's tough sometimes to get up the steepest hills with the 39/23 low gear but so far it hasn't stopped me. I'm in my early 60's and still managing this gearing. And it's nice on the flat to have one tooth difference between many of the cassette sprockets.

Hondo6

Mechanically on the bike, that gearing shouldn't pose any functionality problems at all.

However, if you have any knee problems that relatively high gearing (and possible resulting lower cadence, particularly under heavy load during climbing) may cause your knees functionality issues in the future.

When less experienced in cycling, I used to "grind" at low cadence almost exclusively. I can't say for sure, but I believe that contributed to my needing to get a knee scoped to clean up some frayed cartilage.

Do keep a close watch on your cadence. Grinding puts much more stress on your knees' internals than spinning.

smd4

High gearing? When I got my Dura Ace crank in 2002, I was surprised that 53/39 was the current accepted gearing, instead of 52/42. I felt I was being a little wimpy with that 39.

Hondo6

OP said he's running a 12-23 cassette. If you're climbing hills, 39/23 (lowest the OP has available) is IMO pretty high gearing.

Can you do it? Sure - if you're young and/or strong enough. And if you're young and/or strong enough, you can keep up a reasonable cadence while doing so.

But if not, your cadence gets low - and that puts a lot of internal shear stress on the knee cartilage. Not a good thing if you have knee issues.

redshift1

OP said he's running a 12-23 cassette. If you're climbing hills, 39/23 (lowest the OP has available) is IMO pretty high gearing.

Can you do it? Sure - if you're young and/or strong enough. And if you're young and/or strong enough, you can keep up a reasonable cadence while doing so.

Despite having had this gearing for many years, I would agree with this. I remember choosing the 23 maximum in the cassette as my lowest gearing ( with 39 front ) about 10 or more years ago because I was more concerned about having closer ratios at the other end of the cassette to aid flatter roads riding. Its nice to have 1 tooth separation between sprockets where you do most of your riding. Also I only have an 8 speed set-up so I chose to limit the lower gearing side of the cassette. Back then I remember attempting a fairly long very steep winding hill with the 39/23 gear and it was very tough. I made it but it was all about maximum force being applied to the pedals at almost a standstill in some places. If you are a very strong rider, you may be ok with it but it won't be the fastest way up the killer hills and it will be hard on you. But it also depends greatly on how hilly your ride is. These days my usual 50 km ride route happens to only have limited steep hills in it. If your route is pretty flat, it will be fine.