mountain vs road gearing?

Mountain bikes use low gears which are widely spaced. This gives more torque and control for riding on difficult terrain, and the ability to handle a wider variety of conditions.

Road bikes use higher gears which are closer together. This gives a higher top speed and makes it easier to get your ideal cadence (pedal speed).

Hybrid and touring bikes are usually somewhere in between, often using gears that are similarly spaced to a mountain bike but higher.

Deraillers work with a certain range of gears. They need to move from side to side while not hitting the sprockets nor preventing the chain from moving freely. The rear derailler has to take up the slack as you move from a big sprocket to a smaller one, and different models are able to take up different amounts of slack. An 11-21 cassette should be usable with either a road or mountain rear derailer, but an 11-37 cassette requires a mountain derailler.

The shifters are a different shape depending on the style of handle bar. Drop bar shifters are usually integrated with the brake levers, which is more complicated to make so pushes the price up, while flat bar shifters are separate.

Mixing and matching between road and mountain components is possible though any change requires checking compatibility. Most bikes use drivetrain components from the same group, but having road gears up front and mountain gears at the back, with either type of shifter, isn't that unusual.

Sometimes you see gearing expressed in "gear inches".

In those terms, for example, the traditional 10-speed from 30 years ago had a total gear range of 40 to 100 gear inches.

A modern road bike with a standard double often has a range of something like 40-119; with a triple you often see 31-117.

Mountain bikes, on the other hand, go as low as 21-88, something like that.

Gear spacing is a function of the total range on each chain ring, divided by the number of gears available on that chain ring. It's not accurate to make a general statement about the gears being wider spaced on a mountain bike than they are on road bikes. That depends on the bike.

Thanks for the information. I have a 2007 schwinn super sport. Here are the specs http://www.schwinnbike.com/products/bikes_detail.php?id=747

So do I have mountain bike gearing or road bike gearing?

Thanks

Neither. You have the high gear associated with road riding, 117 inches, while your lowest gear is way down there, at 24 inches, which is mountain bike territory. That's extremely wide gearing.

Some people like to talk about gears in terms of ratios, so that your lowest gear would be expressed as 28 x 32, or .875. Your highest gear would be expressed as 48 x 11, or 4.36.

To convert gears to inches, the formula is, # of chainring teeth divided by # of cassette teeth, multiplied by the diameter of the wheel. A 700 cc wheel is rounded off to 27 inches for this calculation.

Raleighroader said:

Neither. You have the high gear associated with road riding, 117 inches, while your lowest gear is way down there, at 24 inches, which is mountain bike territory. That's extremely wide gearing.

Some people like to talk about gears in terms of ratios, so that your lowest gear would be expressed as 28 x 32, or .875. Your highest gear would be expressed as 48 x 11, or 4.36.

To convert gears to inches, the formula is, # of chainring teeth divided by # of cassette teeth, multiplied by the diameter of the wheel. A 700 cc wheel is rounded off to 27 inches for this calculation.

Thanks for the information, very helpful

Raleighroader said:

A modern road bike with a standard double often has a range of something like 40-119; with a triple you often see 31-117.

Mountain bikes, on the other hand, go as low as 21-88, something like that.

Gear spacing is a function of the total range on each chain ring, divided by the number of gears available on that chain ring. It's not accurate to make a general statement about the gears being wider spaced on a mountain bike than they are on road bikes. That depends on the bike.

I took a look at the Shimano website, figuring that choosing mid-range groups for both types should give a good idea of what typical components are.

First the road group: for 105 cranksets they list 52-39, 50-39, 53-39T, and 50-39-30. For the cassettes they list 11-23, 12-25, 12-27, and 11-25.
I'll pick those that give the widest spacing, and assume a 700*25 tyre and 170mm crank:
Double: 53-39 and 11-25, 41.2-127.1 gear inches, so the highest gear is 3.1 times the lowest.
Triple: 50-30 and 11-25, 31.7-119.9, a range of 3.8
And the narrowest, just for amusement: 50-39 and 12-25, 41.2-109.0, a range of 2.7

As for the mountain bikes: the listed cranksets are 48-36-26 and 44-32-22. The cassettes are 11-32 and 11-34. I've picked the narrowest spacing, with a 26*1.9 tyre and 170mm crank: 20.9-112.4, a range of 5.4

Your comment in post number 3 of this thread makes it clear that it is the mountain bikes that you take issue with, so I had a look at some specs from some major manufacturers, which confirmed that I was being too conservative and should have gone with the wider combination. This has 16.7-103 gear inches, so the highest is 6.2 times the lowest.

Perhaps you were thinking of downhill bikes, with the outer chain ring replaced by a bash guard. The majority of MTBs aren't like this, if for no other reason than they are a bit like SUVs in that many never go off road, and a downhill MTB is a much worse choice than a cross country MTB on road. Not to mention that most of us like to end up where we started (perhaps counting the return as a separate journey), so if we go downhill we'll need to go up too. Anyway, 36-26 and 11-34, with a 26*2.35 tyre: 20.2-86.4 gear inches, so the highest is 4.3 times the lowest. The gears are still more widely spaced than on the road bikes, but it is close to what you say they have so it must be what you meant.

We can find exceptions to the rule (eg single speed and fixed gear bikes, whether road or mountain), but I still say that MTBs tend to have wider spaced gears than roadies.

cycle life said:

Thanks for the information. I have a 2007 schwinn super sport. Here are the specs schwinnbike.combikes detail.phpOpen ↗

So do I have mountain bike gearing or road bike gearing?

According to the component manufacturers your gears are mountain bike parts, though at the front they are as "road-like" in terms of number of teeth as MTB gears get, and you have road wheels which are bigger than most MTB wheels so push the gear ratio up a bit too. Your bike is a hybrid, fitting somewhere between road and mountain bikes, and while there is a lot of variation in hybrids depending on which parent they favour yours is not unusual.

Anth, you are correct. The modern mountain bikes have higher top gears than I remembered, giving them greater gear range than most road bikes.

Cycle Life, the gear range you have, and the bike you have, is aimed at the rider who isn't in top shape, but who is using his bike to help get there. Your 117 inch top gear and 700 cc wheels are designed to give you the possibility of good speed, while your very low low gear is designed to keep you from blowing up on big hills.

Your bike may be just the ticket for you for many years. Or, you may get into such good shape that you just never use those lower gears, or maybe even that you quit using your smallest chainring. At that point you will be a candidate for a road bike with drop handlebars.

Raleighroader said:

At that point you will be a candidate for a road bike with drop handlebars.

I ride a road bike with drop bars and ive got plenty of weight to lose, and hills are my enemy (but im getting a LOT better at them as well).

Of course, i have a Triple crankset, it will be a long time, if ever, that i step down to a bike with only traditional road gearing (2 chainring crank). My mountain bike ive thought of taking the low and high chainrings off, installing a bashguard and calling it a day however. i almost never use anything but the middle... Road bike i use all 3, mostly the big ring unless its windy (aerodynamically challened body of mine..) or im climbing.

while my mountain bike has much more hill-friendly gearing (something like 22T chainring, 34T cassette), you do end up spinning out using that gear, its only good for wheelies really 🙂 or really, really steep hills...

Any help with this dilemma would be much appreciated.

I'm a roadie, but with every birthday, the hills get a bit steeper. I've currently got a 105 triple with a 30 small ring (which I don't use alot, but occassionally it saves my life and keeps me riding.) I'm looking at new bikes (again/still/constantly) and am very tempted by the new Compact Cranksets. So I'm trying to figure out how a compact compares to my triple. How would a 50/34 with a 12-27 cassette compare to a triple (50/39/30) with a 12-23 cassette? What will give me the lower gearing, and will the difference be significant?

I'd really appreciate some expert advice. Thx

Rick Reas said:

Any help with this dilemma would be much appreciated.

I'm a roadie, but with every birthday, the hills get a bit steeper. I've currently got a 105 triple with a 30 small ring (which I don't use alot, but occassionally it saves my life and keeps me riding.) I'm looking at new bikes (again/still/constantly) and am very tempted by the new Compact Cranksets. So I'm trying to figure out how a compact compares to my triple. How would a 50/34 with a 12-27 cassette compare to a triple (50/39/30) with a 12-23 cassette? What will give me the lower gearing, and will the difference be significant?

I'd really appreciate some expert advice. Thx

Well, here is some amateur advice, but it's free, so take it for what it's worth. With a 50/34 compact crank with a 12-27 cassette, your lowest gear would be expressed as 34 inches. That's about as low as you can go with a compact double. Your highest gear with that setup is 50/12 x 27 = 112 inches.

If we contrast that to a typical road triple, we have 52-42-30 on the front, and anywhere from 12-23 to 12-26 on the back. Sometimes you see 12-27 on the back, but not all rear derailleurs can handle the 27 sprocket. Again using gear inches, that yields a highest gear of 117 inches, and depending on which cassette we have, a lowest gear of 35.2 (your current lowest gear) to 31 inches. If you mounted a 12-27 cassette on the triple, your lowest gear would go down to 30 inches.

Practically speaking, at the low end a "gear" is about three inches. For example, in the small chain ring on a triple with a 12-25 cassette, the three lowest gears are 32.4, 35.2, and 38.6 inches. Each step up is about three inches.

At the high end, a "gear" is about 8 or 9 inches.

If we follow the comparison of the 50/34 compact double with a 12-27 cassette, to a 52-42-30 triple with a 12-23 cassette, we have a high gear comparison of 117 to 112 inches, which is not even a full "gear" of difference. We have a low gear comparison of 35.2 to 34 inches, which again is not even a full "gear" of difference.

Your main problem is that you have only a 12-23 cassette on your current bike. You would give yourself one new full lower gear by switching to a 12-25 cassette (35.2 would drop to 32.4), and you would give yourself almost two new lower gears if you switched to a 12-27 cassette (35.2 drops to 30).

If you want a new bike anyway, but you keep your old one as a backup, it still would make sense to switch cassettes if you are having trouble with your local hills.

Hey Raleighroader,

Thanks for the great info!

It appears that a Compact with a 50/34 coupled with a 12-27 cassette provides essentially the same range of gears as my current triple (50/39/30 x 11-23.) So I'd basically lose nothing by going to a Compact, but I could actually gain a couple gears by simply swapping out my cassette to a 12-27.

That's great info as I decide what set up I want on a new bike and/or modifications I could make to my current ride.

I really appreciate the help. Thanks.