Road Cycling - When to shift???

This may seem like a stupid question, but here goes -

I am a bit confused about when to shift into what gear and when to go from small to large chainring. Aside from the obvious, "when it feels like you need to".

I am thinking of getting into racing this season and want to be as efficent on the bike as possible. Also, I don't want to be the idiot who screws up my teams pace line or a lead out by ending up in a gear that will cause an unexpected change in pace for the rest of the guys.

I have read the gear ratio charts and even figured out what mine are. Now all I need is a degree in mechanical enginering in order to understand the stuff!! What I am interested in finding out is what is the optimal shift "pattern" to use. I see that some cog/chainring combinations give me essentially the same gear, but I am not clear on when to use what. What I have been doing is shifting to the 53 ring and dripping back two cogs in back when I do so to keep from having too big a change in cadance or effort turning the cranks. Is this the right approach or is there something more scientific I should be doing?

Until now I have just done what feels right to me because most of my riding has been solo and I haven't had to worry about screwing up anyone else. Also, I have ended up walking up hills some times because I either shifted to too low a gear and lost all momentum or didn't shift in time and couldn't get into a low enough gear before it got to the point that I couldn't turn the cranks. This was on a triple commutor with MTB front crank and Ultegra 11/23 in back. I just got a Lemond double (another reason for wanting to ride more efficently and smoothly) which rides very differently due to the different gearing.

Any advice would be helpful.

You want to avoid cross chaining where you're in your big chainring up front and biggest cog in back. Or vice versa. The idea is to keep your chain as parallel to the bike as possible.

As for when to shift. You shift when you're RPMs drop too low or get too high. There's no formula for when to shift. It's one of those things you just learn how to feel and do.

Go out some day and work at keeping your RPMs at a certain level, say 95. Then just shift as needed to maintain that. That's all.

If you can get in a group ride. You can get in the back and watch the person in front of you. Do some wheelsucking and learn.

Shift down before you need to. Anticipating the hill and spinning into it works for me.

You should easily feel when to shift up. If you ever start bouncing in the saddle, shift, you have lost your smooth, efficient spin.

As you stated, there is some overlap between small and big ring. Picking between similar gears on the big and small ring depends on what is up ahead. If a climb or headwind leg is up ahead, use the small ring. If a descent or tailwind leg or a town line sprint :) is coming up, use the big ring. If you don't know what's up ahead or no changes are expected, stay on the same ring.

Are you a big gear grinder or a high RPM spinner?

This will also determine which ring you sholud be on. If you have put yourself in the position that you have to walk a bike up a hill you definitely need some time in the saddle. There should be no excuse for that, the bike is more than able to shift under load.

Down here it's so flat, you don't need a small chain ring to race.

Are you a big gear grinder or a high RPM spinner?

This will also determine which ring you sholud be on. If you have put yourself in the position that you have to walk a bike up a hill you definitely need some time in the saddle. There should be no excuse for that, the bike is more than able to shift under load.

I am more of an "inbetweener". Untill I knew better I just spun in the 60-70 range. I have been working on uping my cadance and not have an average of about 85-90 (my old legs don't seem to like 100-120 much & and it takes me over LT too quickly at this point)

I think "excuse" is not wanting to destry my drive train and not being preparred for the steep grade of the hill that I end up on. I am talking about a situation where I am standing and still can't get the cranks going enough to back off a bit to shift. I ride alone in the wee hours of the AM and I don't want to taco my drive train and have to walk home.

Thanks for the input

I've never ruined a drivetrain, nor seen one ruined by shifting under load. They're designed to do so.

It seems to me that you have to kick back just a bit to shift under load but you may need more experience to know how to approach a climb so you don't get stuck like that. There is this fine line where you want to shift down. You kind of pick a target on the pavement ahead shift down and you may spinning a bit fast but in a few seconds you'll be rite where you need to be for the rest of the climb. Also during a long shallow climb you may want to shift to a harder gear and stand for a bit than shift back down and sit. For sprints jump a few gears harder get up off the saddle and push to the comfort level of the gear you choose. Find rolling hill terrain to ride in and you'll do a lot of shifting. In a pace line if you are leading choose the gear that you relly have to push in but when in the middle or back often times you'll just be spinning easy or freely but don't be tempted to change to a harder gear b/c the pace will come back to where it was and you'll just have to switch back...

I might have let off a bit before shifting and not even known it. It doesn't require much though.

yea I think with a enough experience it happens naturally, it really does'nt take much...

Sounds like I need a training partner so I can work on maintaining cadance AND speed. It would also give me someone to work on paceline stuff with.

I have plenty of hills and "rolling" hills. The one I invariably end up walking is a 1/2 miller with about a 10 or 12% grade (oh, and there is not approach to it!! You start it from a standstill because the approach is from a stop sign with a right turn onto the hill (can't just hit it and go, too much auto traffic for that). I am sure with repeated effort I can get over it and who knows after all the hours on the trainer and my new bike it may be much less of an issue.

Thanks for all the feedback!!

everyone has a 'confidence' gear. a gear that feels right no matter what the circumstance. work from there.

-if it is mostly flat by you, change to a 11-21 cassette. the gear increments are small and gear shifting can be smoother.

-i shift mostly by feel/cadence.

-it helps to know your route.

-it helps to be able to actively recover

-about that steep hill ---> most people start out spinning too fast in a gear that is too easy. this leads to a higher heart rate faster thus producing lactic acid sooner. the key is to build up momentum without 'spinning out'. so the crucial gear shift comes about 1/3 to 1/2 up the hill when you go from sitting to standing. this is when you need to be at your best.

-i find that the most common mistake is people shift down when they get a little winded instead of gearing up. i feel people get winded in the first place by not being in as high a gear as they can be efficient in.

This thread is interesting, keep up the recommendations.

You ever see someone riding down the street and want to scream "shift!!!" at them 'cause they're either pedaling at 200 rpm or 35?

I shift when I want to change gears ;)