Compact question: 35 or 34?

[MallyG]

I'm ordering a compact chainset for my new bike, and have been asked if I want a 36 inner ring or a 34. When in Italy recently, I saw that almost all were 50/36, so I expressed a preference for this. Am I right?

[Climb01742]

I'm ordering a compact chainset for my new bike, and have been asked if I want a 36 inner ring or a 34. When in Italy recently, I saw that almost all were 50/36, so I expressed a preference for this. Am I right?

for most terrain -- except for alpine climbs -- a 34 leaves you undergeared far too often. and a 50/36 maintains the 14t gap that makes shifting better. if it's a dedicated alpine climbing set-up, i'd opt for 34. but if you plan on using it at home and on climbs, a 36 seems the better choice. good luck.

[Dave]

The 50/36 basically trades one top gear ratio for one at the bottom end. The percentage difference between the rings is still close enough to avoid additional cogs shifts after every chainring shift. Using this compact is not significantly different than just choosing a cassette with one cog lower on each end.

The 50/34 gives you the equivalent of nearly two extra cogs on the low end (a 34/25 is almost as low as a 39/29) but this advantage is not free. Every time you shift between the two rings, one extra cog must be shifted to produce the same gearing progression as a 53/39.

[Ken Robb]

my 50/34 FSA compact is shifted perfectly in my DA 10spd drive train with 12/27 cassette..

[Steve800]

Unless you primarily ride in the mountains, I would stay away from compact. I have Campy Record 34/50 with a 11-23 cassette. For the mountains it's great, but for rolling hills and the flats, it's horrible. Always getting locked out in both chainrings, which forces you to do a lot of shifting. I am going to keep my compact for the mountains, but am going to change to a 39/53, 12-23.

steve

[Ray]

for the reasons noted above. If a 36 is low enough to get you over whatever you climb and you need a 50 on the high end, the choice is clear. If you need a 34 for climbing, go with a 48 big ring. This is my setup - I'm a B rider and a B- climber and I need the low gears. The 48 big also allows me to spend a LOT more time in the big ring and the 14 tooth jump keeps the shifting pattern reasonable when you change rings. I'm perfectly happy with a 48x12 big ring (same as a 52-13), but would find a 48-13 a bit low, so I wouldn't use this with a campy 13-29, for example.

You just have to know what gears you need.

-Ray

[jeffg]

with Campy, you really have to think of whether a 39x29 will be enough. With Shimano a 48/34, 12-27 is a fabulous option for the mountains. Once you go 50/34, you start losing gear spacing and it only makes sense for a 13-29. Otherwise, a standard double with a 13-29 is better than any compact solution with a 12-25, or 13-26. I could imagine a 50/34, 13-29 for Ventoux, Mortirolo, etc. That really is an Alpine solution, however, and not great for riding outside the mountains. If you do go compact, I would recommend a 12-25 and no more than a 14 tooth difference for normal riding and saving 12-27, 13-29 for the mountains.

[Climb01742]

jeff is wise. i'm leaning toward a shimano 34/48 for mt washington, with a 12-27. interestingly, i found out with a PMP crank you can go to a 32 upfront.

[jeffg]

now that PMP makes their own chainrings you have more options. PMP or FRM can give you down to a 30. Consider it for Mt. Washington. That is one mother climb ...

[Climb01742]

yep. the 32 intrigues me. i'd rather have the option of spinning, rather than be forced to grind. especially at the top of washington, where it kicks up.

any long-range weather forecast for your ventoux ride? what's the temp difference bottom to top?

[MallyG]

I have a 53/39 with a 12/25 setup on my Legend. To be honest I am never in 53/12, and find that - on the whole - 39/25 gets me up most things. However, on the Barbotti I really envied the guys who were taking the top of the climb (18-20%) easier than I was. They all seemed to be on Compacts. I just felt I missed another lower gear. Of course, you could say, why not get a 13/27, which is what I did prior to l'Etape. My problem here was that we couldn't get the short Campy derailleur to work with that cassette, so I ended up having to switch to a medium or long one. I also found that there was a bit of a jump in the lower gearing which affected my rhythm. In the end, I went the whole hog and put on a triple, which gave me all the gears but all the weight (also, and I know this is only aesthetics, I hate the look of a triple!).
So, what I hear is that the concensus seems to be to keep the jump between front chainrings to 14, so either go with a 50/36 or 48/12.
In which case, as the majority of my riding is in the UK - with a few continental rides thrown in as a challenge - I'll probably stick with the 50/36. As I said earlier, that seems to be the most popular choice with the Italians, and they seem to know a bit about cycling (and aesthetics, come to think of it!)

[Climb01742]

mally, i think you'll be happy with the 50/36. on flatter terrain, you'll use your 50 more, i think; and on tough climbs, the 36 will come in handy. now...if only the storck would arrive. :crap:

[MallyG]

mally, i think you'll be happy with the 50/36. on flatter terrain, you'll use your 50 more, i think; and on tough climbs, the 36 will come in handy. now...if only the storck would arrive. :crap:

If only, if only, if only....
I anticipate that the bike will arrive in time for me to ride on Sunday June 19th... which happens to be the date of my daughter's Bat Mitzvah, so I can't ride!!!! Doh!!!!

[SMUGator]

I'm running FSA 50-34 and DA 12-25. It's a good combo. I'm still dialing in the upshift on the front, but everything else is spot-on. For me, 34-25 isn't overkill for 15-18% climbs.

[jeffg]

I'm running FSA 50-34 and DA 12-25. It's a good combo. I'm still dialing in the upshift on the front, but everything else is spot-on. For me, 34-25 isn't overkill for 15-18% climbs.

I use a 48/34 with either a 12-25 or a 12-27 with Shimano to have better gear spacing. A 52-13 equivalent is enough for me.

Campy just drives me bonkers for compacts due to the cassette options. To get anything meriting buying a compact you need to drop the 12, which makes the top end a 50x13 at best, and a 48x13 if you want to keep better gear spacing. The result is that I run a 13-29 with a standard double, but will reach for the Shimano-equipped bike at the margins since a 34X27 is that little bit lower.

Mally: Why not get standard Campy with a medium cage RD and then you can run either a 12-25 or a 13-29 depending on terrain? A 39X29 is just a tad lower than a 34X25. If you don't like the gear spacing of a 13-29, I doubt a compact will improve that much. It looks like a 39X29 should be enough for you, unless you want to climb Mt. Washinton ;)

[inGobwetrust]

I recently switched to a compact on my Vanilla and after 2 weeks switched the 34 out for a 36 and am very happy with it. It seems that it shifts better than it did with the 34 and I don't need to switch to the big ring nearly as much. Most of my ridiing is in very hilly terrain and I still seldom need to go all the way down to 36-25.

[53-11]

I'm ordering a compact chainset for my new bike, and have been asked if I want a 36 inner ring or a 34. When in Italy recently, I saw that almost all were 50/36, so I expressed a preference for this. Am I right?

I'd run the 50/34 so you can get away with the tighter cassette. I'm not a fan of 3T jumps that's why I say let the chainrings give you the spread (not the cassette).

If You have problems with rub (due to whatever confounding frame factors-chain stay length,etc) then go to the 36T.

P.S. Has anyone here tried the IRD compact front derailleur with either 9s or 10s Shimano?