TMonk

a 39t would have worked too, and you can use it outside of climbing!

redlude97

I like to do that with my 36T small ring on my compact.

TMonk

Even better.

As I mentioned previously, when riding solo, I use my 39t up to 23mph. Anything much smaller than that is going to result in an annoying amount of cross-chaining.

tntmoriv

Biggest reason is probably the $400 set of dedicated double SRAM Shift/brake levers, they are double only. And compact crank expense. And bottom bracket. Live and learn. On the other hand I am pushing earlier in the season to get into riding shape earlier.

Leinster

You obviously ride at a higher cadence than I do if you're doing 23mph in a 39x13 or 14.

By the time I'm in those gear inches, though, I'm in my 50x17 or 19. Granted there's a gap there that an 18 would fill, but I don't find that I miss it.

I think your "Good job He-Man" comment is a thing compact users themselves also have to get over in their own minds when they switch. With a 52 or 53, the big ring was only for when you were hammering. With my 50, when you pass me on your 39 you might not realise that I'm still just cruising. I'm not in a hurry until I've shifted to the 16.

redlude97

Thats only 100rpm in a 39x13. A 39x13 is good up to ~28mph

Leinster

Like I said, riding at a higher cadence than me.

I left the 13 in in case he didn't think small to 2nd is cross-chaining, but with a 10 speed, to me it is.

Funny enough, back in my 6spd days, I used to ride 42-16 all the time.

TMonk

My SS/FG bike is geared 42/16. That's a great gear.

bbattle

The people that say they spend too much time shifting front rings on a compact don't need to go back to a 52-39, they need to get a 48 or 46T chainring.

Say you've got a 50-34 crankset with a 12-13-14-15-16-17-19-21-24-27 ten speed cassette and a "moderate headwind" comes up. You find the 50-24 (55g.i.) too high so you shift to the 34-19(47g.i.) That would put you in the middle of the cassette. If the equivalent gear was to be found on the 52-39, you would need to use the 39-24(43 g.i.) or the 39-21(49g.i.) combinations. Just a gear or two over on the cassette. I suppose most people people with 52-39 are spending most of their time on the 39T ring as they could then shift to 39-19,17,16, etc. as the headwind died down. This would explain why they'd run out of gears on the compact, they were trying to mimic their old habit of staying in the small ring.

So, if you end up with a compact crankset on your new bike, swap the 50T ring for a 48T.

39-12 is about the same as 50-15 but with the traditional, you'd need to shift to the 52T ring while on the compact, you're in the middle of the cassette with 3 gears to go higher or 6 gears to go lower.


I have several bikes; some have compact and some traditional; I use the big ring on the flats, little ring on climbs. With a compact, I'm spending 95% of my time in the big ring; with the traditional, 85% on the big ring.

Or I ride my singlespeed. It's all good.

mercator

I've got compact cranks on my lemond and cx bikes, and I find myself only shifting the front for steep and/or long hills. As a result I find I have a tendency to mash at a lower cadence on those bikes.
With the 53/39 on my main bike, I use the 39 quite a bit more and at a higher cadence (I hope).

TMonk

^
yep

RollCNY

It is funny, in that this shows the difference in people's riding style. My SS is 47/16, with a bailout flip flop 18. 47/18 is a pretty close match to your 42/16, and I find it annoyingly low unless I am doing a ton of climbing or riding all day into the wind.

f4rrest

Am I the only nut with 50 39 in front?

redlude97

What stops you from shifting?

Dunbar

This will exacerbate the problem of spinning out at speeds above 30mph. I can spin out my 50/12 on a regular descent that I do. And I don't accept the advice to just spin a higher cadence when I'm already doing 100+ rpm. I don't think there is a perfect solution out there. A 39 is more versatile than a 34 on flat ground but in my case requires a ridiculously wide cassette to get low enough climbing gears.

redlude97

A 36T is your friend

Dunbar

I think a 52/36 (or even a 50/36) with an 11sp 11-28 cassette might get me very close to my 10sp 50/34 12-27 setup but with versatility of the the 39. The problem is the non-trivial cost associated with buying an 11sp group set. That's a lot of money to spend to reduce front shifting by a small amount. However, ignoring the costs, it does look like a good solution.

redlude97

what about 50/36 with a 10 speed 12-28 or 12-30? That could all be had for under $150 for a chainring and a cassette

mercator

Not enough hills

redlude97

Sounds like you need a 46 or 48 if you have to mash the 50

Dunbar

Going from a 34x12 to a 36x12 only gets you ~1mph on the top end. The 36x11 is basically equal to a 39x12. Meaning you have a bit of head room if you're cruising at 20mph and need to sprint to make a light or something similar. 34x12 is basically spun out at 20mph which makes it pretty much useless on flat ground. And going for a 10sp 11-28 cassette means I sacrifice the 16t cog in the middle which I would really miss.

I have a grocery getter with a 50/39/30 and 12-30 10sp cassette so I get some real world comparisons to the compact crank on my "real" road bike.

BikeCalc.com - Speed at all Cadences for any Gear and Wheel

redlude97

Yes, but 36x13 gets you 20-25mph which is very useable on the flats, compared to 19-24mph with the 34. That 1mph difference is in the sweet spot for flats

Dunbar

36x13 is 19.6mph at 90rpm. I'm starting to think about an upshift at 90rpm. Nothing worse than attempting to sprint and realizing you're out of gear.

Long Tom

SO much strurm und drang over the oppressive burden that apparantly is shifting front rings on a compact. Get ye to the 6800 store, people!

Wrenchy Veloski

As a roadie & mechanic, I made the following faces* whilst reading this entire thread:
and *Some emoticons are not present in the available menu to complete the full spectrum.

However, despite a seemingly evident lack of applying Rule #5 , the thread was very enlightening and thanks goes to all. Hoping to add something equally positive...

I have 53-39/38, 52-39, 51-38, and 50-34 setups (sorry no road triples). Each has a purpose relative to type of ride, frameset, wheels, current budget, etc. There is obviously a lot of gearing overlap, and things boil down to personal comfort zones (muscle fibres ), as many of you have stated. I do recommend practicing the ability to have an effectively versatile cadence that can change between at least 10-15 rpm.

I very much require the 11t outside of sprinting; more so with lower count "big rings". The only cross-chaining I would not recommend is the small-small combination; it's a slightly bigger reach than big-big, and because the chain might rub on the front big ring beside it causing noise/wear. (if it doesn't rub go for it!) Everything else is fair game, and most front brifters even have trim clicks available for that purpose. Use all your cogs! A 34t inner will get you "lower" (small cogs) on the cassette during hard climbs, and leaves more bailout gears. That being said, get out there and try 35, 36, 37 in 110BCD, and 38 in both 110 & 130 BCD, and 51 in both 110/130 - they are all available. (51-38 on 130 is my stiff secret weapon)

KNOW YOUR GEAR INCHES or GEAR+CADENCE SPEEDS. This leads me to a small, but I feel, important point that my colleagues have agreed upon as well: The smaller the diameter of your front ring, the lower the torque of the lever i.e. crankarm. So, the radius length from BB center to chainring tooth gives more torque when longer. This feels, for me, that the SAME GEAR INCHES are delivered with more power/ease using 53t than 39t. For all you Sagan-esque 'sprinter/climbers' and rouleurs, go for the 52-36/37 or 53-38.

Alright, that is all. Sorry for the very long post: I don't post a lot. In the end, time in the saddle is what really helps; ride lots.