When to change from a compact
 

I picked up my first road bike in October and it has a Compact Crank on it (50/34 in the front & 11/25 in the rear). Half my rides are of rolling hills & the other half are mountian climbs (as big as east coast mts. are considered). When I first picked up the bike, I spent a lot of time in the smaller gear (front) building strength, etc. Now it seems I spend most of my time in the Large ring, except for the serious climbing up a hill. I have found that I rarely am in the 34-25 gear unless I have absolutely spent myself racing someone up the hill. Also, going down the mountains, when I am in a 50-11, I can't spin fast enough for the gears to grab (around 41 mph). So there are 3 gears that I rarely use do to this.

Is there some formula out there that I can calculate what the idea gears that I need? I don't want to over step myself and change to 53-39 and have it be to difficult for me. Equally, if I am never using gears, then I feel like I am wasting. Any thoughts or advice would be great.

Yes. I tried to use the search function & I don't know if it's the computer I am on (I visiting family for the holidays) or the website, but the search function is not working for me today or yesterday.

There is no math needed here, but you can use Sheldon Browns gear calculator if youd like (google it). It will tell you what rpms you will need for a given speed in each gear.

If you want a bigger gear, you'll have to go to the 53-39 and keep the 11-25 cassette. The 53-11 gear will give you another mph or 2 before you spin out. The 39-25 will be pretty close to your 34-23 and since you don't use the 34-25, you wont miss that lower gear. In addition to adding to your highest gear, you may get a little less cross chaining and better shifting with the standard set up.

Sounds like you're fairly strong and better suited for a standard double.

It all depends. Try not to think of compacts and triples as training devices, but rather tools for different purposes. I still ride a compact because I climb some long and steep climbs.

If you're not using your easiest gear combination very often, you can find harder climbs to challenge yourself, or up your gears. For the latter, you have options:
- Change your front chainrings for a 52 and a 36 or 38
- Get a new standard crank with 53/39
- Change the rear cassette to a 12-23 for closer gear choices or 11-25/11-23 for faster descents

Change when you have an actual reason to replace the equipment.

The difference is hardly worth the effort of changing an already-built bike.

+1

I tried out a compact chainset. Ran into the same issues. Haven't been tempted to go compact again since .. I suppose the curiosity was satisfied. If I need lower gearing, I just pop on the 12-27 and I'm good. Isuspect you'll be equally as happy with something similar (maybe an 11-28 in your case, since you like that extra 1 mph going downhill).

700x23c tires, pedalling at 120rpm.
42.6mph with a 50-11
45.2mph with a 53-11

or basically, that's a big hill.

If you're comfortable with your compact set up, I don't see any compelling reason to change it. The best cat 1 racer in the Pittsburgh area uses a 50/36 compact.

I'd be willing to bet that the cat 1 racer friend in Pittsburgh doesn't have to climb too many long hills during his road races (sure he might for training); the point is that his needs are most likely different from the casual rider who just happens to be a bit strong.

Just saying ..

I'm not sure I follow you. The racer I'm referring to does use a compact.

From an old rider....So what if you are in the large ring most of the time? That's not unusual at all. The small gain in your largest gear is not too significant except on the longest steepest downhill. Stay with the compact until its time to replace due to wear. IF you are not spinning at 90+ rpm work on your cadence.

That's what I mean. Just because he does use a compact crankset as a racer doesn't mean Joe Weekendrider has to ..

Do you really need to pedal downhill in a 50x11?

I used to think about this stuff a lot until I got a fixed gear.

Az

Same here... ....but that doesn't mean that I'm going to toss out my geared road bikes...:D

I just bought a fixed gear bike and damn is this thing such a blast to ride. Uphill, downhill, just pedal harder. I've already taken it all around San Francisco and can get up and down most of the hills.

As far as swapping cranks, it would be a lot easier to start with an 11-23 or even an 11-21 cassette.

A very large gear is very handy when dealing with extended descents. If you're maxing out your gears then you can use higher gears, up to perhaps 50-55 mph. Usually it's better to sprint and then tuck though, since you slow when you are pedaling (versus a nice tuck). Problem is then people expect you to be good when it goes uphill lol.

It's useful even at slower speeds, say down to 35-38 mph, because you can use the big gears to accelerate or move up without digging into your aerobic or muscular reserves. I love scooting by riders who are spinning uncomfortably fast on a slight downhill and I use this tactic all the time in both group rides and races.

I used to run a 54x11 but now run a standard 53. I loved the 54 because if a guy behind me copied my cog selection, I'd have a bit more top end compared to him. Depending on how things go I may get another one for 2008.

Regarding Cat 1s and compacts, one does not necessarily make the other. For example a lot of pros used them too, but that doesn't mean we should run out and get one too. A good strong rider I know moved up to Cat 2 in 2007 (he was a 5 in 2006 I think). He has an insane aerobic engine and spins like a mofo all the time. I'd be spinning up a hill in a 53x16 and he'd be spinning his 34x12 or so (at that point he was still a 3). I thought he made a mistake and forgot to put it in his big ring (I did that once, did a very fast crit in the small ring, a 45T, realizing my mistake at the bell lap). Since we'd talked previously about tactics and techniques (my first observation and his correction led to his first win), I rode up to him and discretely pointed out he was in the small ring. He looked at me like I was crazy and said that's what he wanted. If I was rolling around sitting in the field I'd blow up spinning at 120-130 rpm, but he liked that. He later bridged a 30 second gap on his own in very windy conditions - so his high rpm thing didn't bother him too much apparently.

I'd see if there's a way to trade someone a compact for a standard or some other relatively inexpensive way of doing it.

cdr

Right. Many people avoid compact cranks because they think their use signifies weakness or noobishness. My point was that, when confronted with hilly terrain, even exceptional cyclists often opt for lower gearing.

Just curious: what kind of compact are you using?

If you're already running 110mm bcd then you can buy a 52/39 combo for your current crank.

Check FSA's site here:

http://road.fullspeedahead.com/fly.a...id=100&pid=155

I run a 50/36 myself...although the shape I'm in currently has me poking around my garage looking for my 34t.....:(

I rode a 50x34 compact last season. When I swapped the 12-xx cass for an 11-xx, wow! Lots more descending speed. It was fun to pedal away from the pack on the downhill. Totally worth it and I don't think you have to sacrifice anything because isn't there an 11x25 cass?! If not, make one by combing two cass and selling the "left over" cass.

are you running campy?

If you want more gear why not look at FSA and get a bigger(more teeth) chainring.

....and with that fixed gear you have an excuse not to do any big hill climbs or riding in the mountains....what a convenient solution. Wimp :)

When to change from a compact.
 

Simple Answer.......................Never

I have two carbon bikes, one w/compact Campy Record, one standard Dura-Ace.

The Compact crank has too many advantages to list.

The smaller ring creates the opportunity for major climbing without a 3rd ring.
The 50T ring allows for closer together ratios, from gear to gear. Great for finding the perfect cadence.

The only disadvantage is spinning out of your top gear while running downhill. You don't spend the majority of your riding time going downhill. I live in the foothills of North Georgia, and there is very little flat ground.

The major crazies are so worried about running in big gears, doing everything the same. 80% of your gear ratios are available on both chainrings. You might be a couple cogs apart in the rear, but they can be amazingly close. Look at Sheldon Brown's charts. You can probably run up to 20-25 mph in a 50-11. You can jump into the big ring for flats and downhills. I ride in the big ring most of the time, but when climbing long and strong, it's great to have the bottom end to work with. In the Tour de Georia, several pros ran triples or compact cranks on the climbing days.

Unless you're a flatlander, I can't see much use for chasing bigger gears, unless you're racing. I have seen 49 mph on both my bikes. Don't need overdrive.