SLOWROADIE84

Hello fellow roadies. Im new to this site and found myself continuously hitting google to search things and I always end up on here. Decidied to just register.

This question has been answered before Im sure but I cannot find a definite answer from all the searching. So I apologize ahead of time if I somehow missed the magical answer Ive been searching for.

I follow a few people who race around town on Strava. Since they are stronger than me I always try and see how close I cant get to their times on segments. Last week climbing Glendora Mountain Road I took a new approach to how I excecuted the ride. Basically I ditched my "low gear high cadence" mentality while climbing and decided to lower my cadence and somewhat mash up the climbs using my 50-24 set up most of the day. Checking my garmin my cadence was almost -20rpm from my usual 80-85rmps up that climb, but I got all kinds of PR'S. Shaving some of my segment times by 5 mins and my avg speed on segments by 1.5 mphs.

So Im thinking, this could be better for me. but not so good for my drivetrain being almost at the end of my gearing on the big chainring.

Would it be more efficient to be on the 34t and use say a 19t in the back? Will I lose power? I guess I could just try I just wanted some input.

Thanks and sorry for the novel I just wrote!!

xjustice09x

At the same rpm you would be moving faster in 50-24 than 34-19. If you could maintain a higher rpm for longer in the 34-19 that gearing may be better.

You can play around with gear calculators to analyze different scenarios. here is one https://sheldonbrown.com/gears/

jmX

I think it mostly means you were slacking off with your high cadence in the low gear, and shifting to a steeper gear basically means you can't slack off as much and are forced to push yourself a bit more. This would all be apparent if you had a power meter.

For the 40-60 minute climb that GMR is, you're almost certainly best off working at a cadence in the range of 80-100. Whatever gear that is for you, use it - and stop taking it easy at high cadence. Since GMR is such a long and steady climb I think it's the perfect place for you to experiment...just choose one gear harder than you normally would and see if you can keep 85rpm or higher for 10 minutes or more. If you can, go up another. Repeat until the sweet spot is found, and come back to brag about your new Strava PR's next month.

If you were talking about a 1 minute climb, none of this advice would apply.

f4rrest

34-16 or 17 should be your closest equivalent.

That's a fun climb, and it sounds like you might prefer a standard road double instead of compact.

rpenmanparker 

To directly answer your question, yes the non-cross chained gear combination is better overall for your bike. If the ratio is the same as 50/24 then the results will be the same too. 34/19 is as close to 50/24 as you can likely get on any common rear cluster. The difference from 50/24 will be negligible. Just do it.

carpediemracing 

The 34x19 is a lower gear (48") vs the 50x24 (56"). It's about one shift worth, maybe two. You can use that Sheldon link above to calculate your gearing. You'll probably notice some overlap.

Strava is allegedly pretty reasonable at guessing your power numbers on a climb, if your weight (and overall bike weight) is accurate.

For a given power output on a given day you'll go the same speed. It doesn't matter what gear you use. If it takes, on a given day on your GMR climb, 250 watts to go 10 mph then it takes 250 watts to go 10 mph. You can use any gear you want but if you're going 10 mph it's 250 watts (or whatever wattage/speed for a given day). This means you can use the gearing to shift feel of the work from spinning (personally I have a hard time with spinning - over 85 rpm - and working hard) to pushing (which I find much more natural - 60-85 rpm). I'm normally comfortable sitting in a group at 100-110 rpm so it's not like I don't spin, it's just that under pressure on a longer climb I prefer to push more. For shorter climbs even more so, using muscular power to roll over a hill (so keeping it in, say, a 53x15-17 instead of shifting into a 39x19-21 or something like that).

carpediemracing 

Also the straighter the chain is between the chainring and cassette the better. You can lift the rear of the bike and pedal in both the 50x24 and the 34x19. You'll probably feel some difference in resistance when turning the pedals.

I'll use the big-big (53x25 or 53x23 for me) for short durations but if I'm making a steady effort, like in the wind, and I find myself shifting into the big-big or even the big-second-biggest, I'll shift into the small ring and find an equivalent gear.

OldsCOOL

Get a road double and tool for removal, swap in that road crankset and see what that 39 will do.

hueyhoolihan

won't a compact crank carry a 39t chainring?... maybe not. things change.

cthenn

So if you are 20 rpm's down from a usual 80 rpm's, that's 60 rpm's and that's way too big a gear, esp. for climbing. As someone pointed out, you may have been slacking or taking it easy in your previous rides. I'm actually surprised you PR'd by that much mashing 60rpm's...that's pretty hard. Try a combination with your small chainring, but a couple of cogs smaller in the back.

Compact is 50/34. Mid compact is usually 52/36. 39 only comes on a standard crankset (at least when buying new).

Icculus21

25 or 6 to 4?

OldsCOOL

I've climbed a few hills with that.

SLOWROADIE84

I think youre right about that. It gets pretty easy to slack in those lower gears if you arent trying to chase anyone.

According to one of the main segments that have most of the climb. Strava estimated that my avg. wattage was 165 with an average cadence of 65 and an avg speed of 11.7. I'm 5'6 130lbs. Im not sure if thats decent. Seems pretty damn low to me. But then again I know very little about power.



Thanks for all the responses and it seems like the way to go would be to experiment with the small chainring/higher gear combo to keep my drivetrain happy. hopefully my times will improve too!

SLOWROADIE84

Actually I wish I could swap the 50t for a 53t but unlike the DURA ACE crankset, my Ultegra crank won't fit a standard big ring. Different BCD'S. I would like the best of both worlds. I should have thought of that before upgrading!

carpediemracing 

You can do some steady grades (not necessarily as long - a few minutes is fine) and do some experimenting with how hard you can go. For power some of the time steps are one minute (60 seconds), 5 min, 10 min, 20 min. You can take 95% of your 20 minute time and that's approximately your FTP. You can find a variety of hills or use just one hill but go really hard for a minute or 5 minutes or whatever and see what Strava says (note landmarks and make the various things private segments).

For me, for example, when I do Palomar I'm really hard pressed to do more than 155w for the 2 hours it takes me to climb the whole thing. It very slow for me, since I'm a good 40+ lbs heavier than you, and only an inch taller. My FTP - theoretical sustainable power for an hour - is about 210-220w, which is low. It seems about right since I can barely sprint if I do 200w for an hour. At 160-180w I am fresh enough to make efforts at the end of an hour. However these power levels were enough to get me up to a Cat 2 on the road.

What you'll find as you get more experienced is that you can really bump up the power curve in a particular area, like the 1-5 min range, or the 5-10 min, or 20-60 min, etc. You'll also really increase your sub-60s power number (hard to measure using only Strava, it's too inaccurate). The sub 60s power increases are as much a combination of learning how to pedal as well as overcoming mental limits. I think all riders looking to improve should do some massive gear hill efforts. It teaches you that you can actually use some crazy gears to get up the smaller hills.

This is how I learned:
https://sprinterdellacasa.blogspot.co...ic-and-me.html

Hope this helps.

redtires

Wait a sec here....are you using the brand new four arm cranks? If it's a five arm crank w/ a BCD of 110, you can get any size chainring you'd like. I wasn't a fan of the new Shimano crank design to begin with and if you can't get other sized rings for...I'm even less of a fan.

SLOWROADIE84

Yeah at least for the front chainring you can only use ultegra specific chainrings. The design is pretty different from other cranksets you know?