I'm getting a lot more comfortable with the gearing on my Surly LHTD so now I'm wanting to experiment a bit. The question is, when is the best time to change the front gearing? Let's say I'm headed up a long and tiring hill with the chain on the middle gear (front). Should I wait until the chain is on the lowest gear in the back before changing the front to a lower gear? Or, should I change the front at some earlier point to avoid "cross chaining"? Please excuse my lack of knowledge and correct terminology but I'm truly a novice bicyclist.

Your question is a good one. Unfortunately, there is a one-size-fits-all answer. There are almost as many shifting strategies as there are cyclists! My advice is to experiment, and learn from trial and error what works best for you.

My opinion: it depends. Ideally, I change to the smallest chainring before pedaling gets really tough. I try to maintain a constant cadence of 80 or 90 rpm, and shift before it gets too hard to keep going at this rate.

If I am approaching a long, steep hill, I sometimes shift to the small chainring, adjust the rear so that I am pushing against resistance and am at my comfortable cadence, and then gradually gear down, one at a time, until I am in my second smallest (or smallest) gear.

Getting the front derailleur to shift is MUCH more difficult under load, so I typically shift to the small ring at the beginning of a climb and then shift the rear as needed for the cadence and effort I can handle as I proceed up the hill. That often means that when I do the front shift, I quickly shift a couple of cogs harder in back so there's still pedaling resistance.

While the chain isn't running parallel with the bike, this isn't cross chaining. The middle chain ring has, or should have all of the rear cogs available to it.

With practice you will be able to anticipate which chain ring is appropriate for an approaching climb that will suit your climbing style.

Brad

The front derailleur is trying to shift the part of the chain that is under tension as you pedal, the harder you pedal the more tension. The rear derailleur shifts the portion of the chain that is only under the weak tension provided by the cage springs. So, if you really needed to down shift the front because you waited too long, it might not shift while you slowly roll to a stop.

I shift the front several seconds before I will need that gear. I often will pedal harder for 2 or 3 revolutions to get a bit more momentum, then shift while I simultaneously ease up on my pedaling effort.

If you ever are pedaling hard and drop a chain during a front shift, you might have a really bad day. That is another reason to ease up on pedaling pressure when shifting the front.

I am just elaborating a bit more on the points made by Dfrost (below). The key is anticipation.

This.

Keep in mind we are talking about needing/wanting to use your lowest gears.

It's much faster and reliable to rear down shift when going up hill. (Key concept.)

If you are not in the small ring in the front and are in one of the lowest 2-3 rear cogs, shift-down in the front and shift-up in the rear BEFORE the hill get hard. (This basically gives you the same gear but set up for easy shifting when going up hill.)

There is a lot of overlap in gear range. A front shift is often equivalent to shifting 2-3 cogs in the back. (Key concept.)

Keep in mind that all this shifting takes some time. Also, you want to reduce pedal pressure when shifting the front (front shifts are slow). This means you want to anticipate the shifting and do it where you won't lose to much momentum.

If you ride in groups, you will often see people who don't use this technique have all sorts of shifting problems!

With practice/experience, you'll often be able to do this later.

You can often even use this trick within a pedal rotation if you time things right.

No, there is a basic principle and technique that cyclists should learn. Too many cyclists have no idea about it. (Experienced and competent cyclists might do all sorts if things but they, presumably, have the basics down.)

This is the correct technique (you are also shifting up in the rear to get the same gear). This is what the OP needs to practice and get good at.

OK, I get the picture, thanks for all the input guys.

I usually combine that with a double upshift on the rear. Pedal harder for two revolutions, double upshift on the right, single downshift on the left, ease up on pedals as you're shifting, then back on the power as soon as the shift completes. It probably took longer to type it than it takes to do it. And the same technique can work when going between rings on the way up...downshift two rear cogs as you're jumping up a ring in front.

remove your front derailleur and understanding when to shift will be immediate. IME, it's unnecessary.

What??? are you some kind of saddest? Why not just tour on a fixie?

Unless maybe you have the bucks to invest in a Rohloff Speedhub?

I said that earlier. Riders need to learn that particular thing .

A n-sec before it wears out.

Sage advice!!

OK, I gave it a go today and it worked just as advertised. My primary concern was to avoid cross chaining and was successful in doing so. I'm practically an old hand at it now!

I usually ride in the middle chainring. If I approach a hill that I think I might run out of cogs on, I'll shift to the small chainring. I don't use my large chainring unless I run out of cogs on the middle chainring.

I do this for all rides unless I'm focusing on training, in that case I will try not use the small chainring.

Or change it on a regular schedule, like the batteries in your smoke detector or motion sensor alarm.

How To Shift Your Bicycle's Gears

I had issues when I was learning on hard hills and new to being clipped in when I couldn't get the front to shift under load fast enough and was going slow enough that came close to falling. I almost always drop to the small chainring before heading up most moderate to steep hills and adjust the rear accordingly. I've had a few issues lately too where the chain dropped off dropping to the granny chainring under load leading to some very rapid unclipping as my bike grinds to a halt.

You can get chain catchers, like the deda dog fang. They are very effective in preventing chain drop. I'm running a 22-38-48 triple, meaning I have quite a drop from middle to granny, but it's very rare for the chain to come off with one of these devices.

+1, and it only takes about 10 minutes to install. Whether or not I installed it correctly or not, it has been on there for 3 years and has worked.

Read the terrain anticipate the gears you will need
Shift the front Down before you have to .. so you wont need to in the middle of a climb..
up shift in back , then as the hill gets steeper shift to lower gears on the rear , it will make them better ..

then Up shift the front at the crest of the hill as you start down the other side.

derailleur systems work easier when not pulling hard on the chain ,speed up and get momentum ahead for the shift
with a reduced chain tension.

I've never heard of this, but since I have this problem sometimes, I'm thinking I might get one! Thanks for the heads up!