bruce19

A little background before my question. I ride with a standard crank set (53-39) and a 10 speed Dura Ace cog set of 13x25. On a flat road, riding solo, I can do about 24-27 mph. One of the club members I respect and get advice from (a former racer at a high level) rides with a compact crank and suggested I consider it. We talked about gearing and chain inches and such and I've been mulling it over. Here's my question. Does it really matter if I mix and match cogs to either a standard or compact? Can't I achieve the gearing I need with either? One of the reasons I ask this is because changing out to a compact can be pretty costly and if I can get the same result with new cogs for the standard, why bother?

jppe

You are correct. No reason to change unless you are wanting much easier gears or you want to expand your gearing. If you can hold 24 mph on flats solo it sounds like you can handle a 53.

bruce19

Went out and counted cog teeth. Oops. Turns out the LBS said they were going to install a 25x13 but the actual count is 25x12! At this point I can spin that 39x25 fairly well when climbing thanks to a 12 lb. weight loss this season. But, I think I will go to a 13 or 14 just cause it allows me to spin with the rpms I like. I like to stay in the 90-100 rpm range and actually hit 110 rpm yesterday on a 30 mi. ride. That was a high for me.

tsl

I run standards or 52/39/30 triples on all my bikes, and I own a compact for one of them.

A compact isn't going to do a thing for you at the speeds and cadences you're talking about. Compacts give you lower gears for climbing. If that's not a problem, then you don't need a compact.

I absolutely detest compacts in 51 weeks of my usual cycling. My typical cruising speeds are in the 18-21 mph range, which makes me cross-chained in either ring. Worse, it means a front shift combined with four rear shifts when I go faster or slower. With my standard, my typical cruising speeds fall right in the sweet spot of my preferred 12-23 cassette, and I have plenty of cassette left over for faster or slower speeds.

As for climbing, I've worked long and hard and consistently on the HTFU part of it and can outclimb almost everyone I've come across on our local terrain. It was early season, but once, this old man on a standard left a racer on a compact puking on a climb. The point is that HTFU trumps gears.

In the 52nd week of the year--next week, as it happens--I ride the Highlander Cycle Tour, billed as the toughest century in the east, with up to 11,000 feet of climbing. Although I ride the metric route with only 7,500 feet of climbing. For that, I own a compact and 12-27 cassette. I'll install them on Wednesday the 5th, and remove them on Sunday the 9th.

GlennR

^^^^^^
Rochester is not level ground, my son went to school at Geneseo and I rode with him twice. He's a climber and leaves others in the dust, but then he's only 21.

It's impressive that @ 50+ you can climb so well and one day I hope to maybe keep you in sight. But until then, i'll ride my compact with a 11-28.

And yes... I need to HTFU. I'm working on it.

chasm54

Bruce, the answer is that unless you need the gears for climbing, I can't see why you would move away from the standard chainset. If you do need the gears for climbing, then a compact (or a triple) might be the way to go. The triple would bump the costs up still more, though.

When I came back to cycling I more or less defaulted to a compact on the advice of a friend who a) knew how out of shape I was and b) rightly wanted my aged knees to spin rather than mash. I currently have two compact set-ups - a 50-36 on the Giant TCR that I race, with a 12-25 cassette, and a 50-34 with a 12-27 on the other road bike (currently in bits). Obviously I can swap the wheels/casstettes between bikes easily enough. Of the compacts, I much prefer the 50-36. There's something about the 16-tooth drop on the 50-34 that just makes it more difficult to find the right gear when shifting up front, and gives rise to a lot of double-shifting. YMMV.

At some point I will abandon the compact on the race bike and revert to a standard, and save the other bike with a compact for long days in the hills. Were I starting again from scratch, I'd have one with a standard crank and one with a triple, because I like the fact that a triple can give you a big range while retaining nice tight ratios at the back.

And one other thing. If you can crank along at >24mph, why aren't you racing?

bruce19

I have thought about it. But only with regard to TTs. My club is going to have one next month and I'll probably give it a go.

Today I'm going to go out to find a level piece of road at least a mile long and see how fast I can spin the pedals in that 53x12. Never really paid attention to that before. It will be an experiment.

chasm54

53/12 is a bigger gear than Eddy Merckx used to ride on the road. Thirteen was as small as it got, then. He seemed to do OK.

AzTallRider

tsl nailed it.

The key criteria in the decision is whether your typical riding causes a lot of chainring shifting. It's a pita to always be right at the edge in between the big ring and the small ring. I use a 53-39 because of that, and because otherwise I'd spin out on fast stretches. I swap cassettes a lot, training on a wide range 12-28, and racing on 12-23, 12-25, or 11-25 depending on the terrain.

And since you are thinking about doing TTs, be aware that you will want the tallest gearing you can get for that. Many people go with a 54 chainring and an 11-xx cassette. I got the 11-25 specifically due to the needs of TTs, and am considering boosting my big ring to a 54. On a TT bike, if there is a tailwind or any sort elevation drop, you are well into the 30's, and many people use a lower cadence for TTs. You don't want to run out of gears on a TT, since maintaining a steady cadence is considered beneficial.

Homeyba

Not everyone rides like Eddy Merckx, just like not everyone rides like Lance Armstrong or Jan Ulrich. We all have a cadence that works for us as individuals which is why my gearing works for me and may not work well for you. Gearing is an individual thing that should take into account the riders cadence, strength (muscle and cardio) and what kind of terrain they are riding on not what anyone else is doing.

AzTallRider

However, we all share some basic physiology, and we all must abide by physics. The result is that competitive cyclists have cadences that fall within a fairly narrow range, and that range is generally higher than the range of non-competitive cyclists. Cyclists that want to be competitive (and I realize not everyone does) see their cadence gradually increase along with their skill and fitness. One of the quick and easy ways of knowing whether someone you meet on a ride is going to keep up is to evaluate their cadence. There is the occasional grinder that is also fast/strong, but it is rare.

chasm54

Hmm, I agree, but I think you may be responding to one of those rarities. Homeyba is plenty strong, by all accounts, and likes to push a big gear.

Actually, my Merckx reply was meant to be flippant. I don't know what gears he pushed in TTs. You're certainly right about needing tallish gears for the downhills, though, it's quite difficult to keep the power on as the road slopes downwards.

PatW

Well, I used to ride a 13-24 with a 53/39. I could hit 38 mph on the flat in a 53/13 and then I was starting to spin out a bit. Excepting down hills, I don't think that one is going to use any of the small cogs very often unless you have a really low cadence.

AzTallRider

I have a friend, built like linebacker, who we like to say "flattens the hills" rather than climbing them, and he does so at a really low cadence. His torque is off the charts, and hanging with him on the flats is truly challenging.

Mobile 155

I have both but in my case I prefer the compact for all around riding club rides and short road races with some climbing. But then that might be because I like tripples only slightly less than TSL likes compacts. For long flat or rodes with rollers my road doubble works fine. With today's 10 speed cassettes you can get some of the same gearing from the road crank as the compact. Looking at Saint Sheldon's gear chart you will see a 52x12 at 100 rpm and a 170 crank, I have short legs, gets you 33.9 MPH. Drop into a 50x11 and you get 35.5 at the same rpm. I believe you can get a 11x28 that will work with a road crank but I could never spin a 52x11 and I can just bairly hit 100 rpm with a 52x12 on the flats. That is just me however.

My road crank is matched to a Dura Ace STI, cranks and derailleurs. My compact is matched to SRAM Red. But I ride the compact about twice as much as the road crank because I can simply slip a climbing wheel and cassette on it for long climbs. I often change wheel sets depending on the ride we will be doing. Just my opinion however.

Homeyba

I'd probably qualify as one of those but in truth my cadence is all over the place depending on what I'm doing. I run pretty big gears sometimes (60/11) but not all the time. It just depends on what I'm doing. That's why I have a box of chainrings and cassettes that I liberally swap in and out depending on the event that I'm doing. If you show up at an ultra-distance race, I'm not too unusual there. There is some science that says the most efficient cadence is 60rpm+/-. You see a lot of long distance racers run big gears so that we can put it in that big gear and actually recover on the bike. I can put it in that big gear and cruise at 25+mph across Kansas but when I'm climbing in the Rockies or Appalachians I prefer to spin at a much higher cadence.

bruce19

I'm going to tell all my friends that I was compared to Eddy Merckx!

AzTallRider

From the reading and listening I've done, I think it depends on how much torque is involved. As a general rule, higher torque limits the reps you can do, hence the benefit in spinning at higher rev's, and lower torque, to generate the same power output. But there is also the theory that "tired muscles are slow muscles", and adherents to that advocate slowing cadence over the course of a long hard ride. Yet another factor is that many of us recover best by spinning at low torque. In fact, a study I read showed that to be the single best method of recovery they tested, beating ice baths and compresses. But it was at ~80w, which is really low power. Personally, I'm going to be triple digits when the power requirement isn't too extreme, and in the mid 90's if I want to maximize my power. I take about 10rpm off when I'm OTS.

Homeyba

I'm going to have to give you a better answer when I get home from work but I will say that I tried to train myself to spin a number of years ago. I can tell you there is no way I can recover on the bike with a triple digit cadence. I did get to where I can comfortably spin at 90rpm but as soon as I got in a race and got tired, I'd revert back to a slower cadence. Sometimes that'd be 150 miles or 300 miles into a race but it always happened. Now I don't really worry too much about specifically where my cadence is. I vary it depending on how I'm feeling and what I'm doing.

John_V 

Boy, I'm sure glad I don't race and don't have to worry about all those different cassettes. However, I did get to (and held) 24.8 mph for just over a mile this morning trying to outrun the rain (which I failed to do). That was on a compact at a 50/14 gearing and around 85 rpm. I don't seem to last very long at higher rpms and do much better at cadences of upper 70's to mid 80's.

BikeWNC

If you need slightly easier gears going to a compact crank will allow you to get that and keep a bit tighter range between gears on the cassette. Often people, myself included, use a compact with a wide range cassette which can make the jump between gears a bit too much in some cases. Ideally we could all have the perfect selection of gearing with close ratios covering the full range required (and not use a triple which is clunky IMO). However, until they make a 15 speed cassette I don't think that will be possible. So pick what works best.

bruce19

So today I went driving around my town (Lebanon, CT) to look for a flat piece of road approx. 1/2 mi. long. The idea is to experiment with different gear combos to see how many rpms I can manage in each. I actually drove around with a 4' level and found a road with about .4 mi. of "relatively" level roadway. As soon as I can I will try it both ways to see how fast I can do it and to see what my max rpms in each combo might be. I feel like I'm doing a science project.

AzTallRider

It takes practice/training to get a cadence up.

Sounds fun!

chasm54

From what I have read, 60rpm is roughly where you are most efficient in terms of generating a given amount of power for the least possible amount of oxygen burned. In other words, it is the cadence at which you are placing the least strain on your cardiovascular system. It therefore makes sense that you recover on the bike at that cadence, but the cost must be potential fatigue in the legs.

bruce19

So I finally went out and did my experiment today. To recap a bit....I'm trying to determine whether my 53x39 crankset and 25x12 (10 cog Dura Ace) are appropriate for my age (66). weight (185 lbs) and fitness level.

I went out with a 4' level and found a piece of road that is relatively flat. I'm guessing it's 0.5% up or down. This road is 6 mi. from my house so that was my warmup. All runs were done on the hoods and not in the drops. The first run I did was both ways on the road in 53x12. And the result is......26 mph on what I assume is the down slope at 76 rpms and 21.8 mph at 63 rpms on the upgrade. There was a noticeable breeze coming directly from the side. Nothing problematic but noticeable. I then ran in different cogs on the down slope only.

53x13......26.5 mph@83 rpm
53x14......27.0 mph@90 rpm
53x15......27.0 mph@98 rpm

My take away from this is that I probably don't need the 53x12 and 53x13. Maybe I don't even need the 53x14 for the riding I do. Just wondering if anyone has any insights or opinions about this. I should mention that sitting and spinning up to 110 rpm is not a problem for me.