SmallFront

I have no idea how to calculate "gear inch", but I run an Alfine 11s with 39T up front and 20T at the back on a 26" with Schwalbe 1.6" Supremes. The gearing fits me just fine. I mean, I can outspin myself down hills, but it doesn't matter. The (cargo) bike is like a freight train when loaded, and I don't have a need for more speed.

Before actually riding the bike in the highest gear I thought it might not be high enough, but I have come to realise that with the extra length of the bike compared to a normal bike, I can't go much slower without loosing the balance anyway, so even that is fine too.

Also, since the bike drag is a bit more than on, say, a race bike with drop bars, I find that at a certain speed the power needed to continue at that speed outweigh the advantage, if that makes sense.

donalson

sheldon brown does it for you ;-) https://sheldonbrown.com/gears/

Erick L

I misread the question at first. The lowest top gear I've used was 95" and it was high enough. I might go back to that or a little lower (~90") if i change my triple to a double. My current top gear is 108.5" and the only time I found it useful was to keep pedaling on long low-grade descents in the rockies/coast mountains without spinning like crazy.

wphamilton

I've never toured but I want to and I will when I get the time. When I mentally build my bike I think I could live with 90 gear inches, maybe even less if really loaded. I don't envision many long stretches of high speed time trialing or fast pack riding on tour - tell me if I'm wrong about that.

Tourist in MSN

Do I NEED a really high gear on a touring bike? NO.

But is it really nice to have some really high gears on those really long steady downhills? Absolutely. I have pedaled with a low effort/low cadence downhill on several tours for distances of over 20 miles on several occasions with a downhill grade of 1 or 1.5 percent. I really enjoyed having those high gears for that.

A steady strong tailwind is another reason some high gears are great to have. My highest two gears are 111.7 and 121.9 gear inches (559X50mm Dureme tire).

But the lowest gears are the must have gears. My lowest two gears are 19.3 and 23.8 gear inches.



Front, 52/42/24, rear 11/32 eight speed cassette.

MassiveD

Obviously those examples aren't going to happen, but some of the best riding you may do will be either hills, or even better a long flat, but sloped your way run with a tail wind. It is sad to waste it.

On the hills there is a caution element in there. For me, touring is not a danger sport, done plenty of those. But I just don't care to have a high speed accident in a foreign country riding a bike. Most touring bikes are not set up to control high speed decents flat out crazy. If I am going to burn it, I would rather do it on something more worth while.

But on the other stuff, the gear keeps pushing us into ever crazier racing inspired set-ups. It ought to be possible to have both ends of the spectrum with 10 speed hubs, or whatever we are up to now. I prefer 7-8 speeds, and the rational chains, and cheaper parts, but if I am running bar ends, and high gear counts, I should get a reasonable top end gear. If I was running brifters and tight spacings then maybe I would be for keeping the upper end low, still.

That is the trade-off on a rational basis, one is giving up efficiency for the once in a lifetime ride, but one needs the set-up that allows one to shift like a rat on crack. And one needs to be able to stop the bike at high speeds and high weights (if one is carrying some gear).

It's all a system: Big engine, little engine; terrain; light or heavy load; old gear, new gear; efficiency of shoe to pedal and spinner or cruncher. etc...

nun

To directly address the OP's question the lowest top gear I'd tour with would be around 65" so that I could ride at 15 mph doing 80 rpm. That's an acceptable touring speed on the flat and downhill I'd just coast. I've ridden 65" as a top gear on a tour and it was ok on the flat and pretty good for most of the hills too.

In reality I set my gearing up so that 70" to 65" is the gear I have when the chain has least angle as it's the one I ride most. 46/34 x 12/36 gives a nice range of 103" to 25", but I'd also be happy with a mountain double as low as 36/22 which would give a range of 81" to 16.5"

SmallFront

Thanks!

Darth Lefty 

A week or so ago I spent a couple hours building up a spreadsheet with a ton of different freewheels/freehubs, cranksets and tire sizes. The original impetus was planning changes to my own bikes - my Paramount bottoms out at 48 inches which is brutal with my bad ticker and steepest climb, my MTB-with-1.5-slicks tops out at 95 which is too little for my best downhill. I learned a lot. For instance...

• MTB cassettes have very nice even spacing between shifts. Road cassettes generally have two sections, a tightly spaced top end with 1-tooth shifts in between ("corncob") and a nicely spaced low end that is like the middle of a MTB cassette.
• 8x11-30 has beautiful spacing. When you plot it up on a log scale it gives a nice straight slope. 11-28 and 11-32 are compromises on it; the 11-28 might be all the low end you need and allow for a medium cage derailleur, the 11-32 gives a lower low gear which you might want if changing from 26 to 29er for instance. 9x11-34 is the same spacing as 8x11-30 but with one lower cog.
• The ratio of the rings of a double, or the top two of a triple, are spaced about 4:3. This is equivalent to about two shifts on that nice MTB cassette spacing, so this is what allows that easy downshift when changing rings - just pull the triggers, go down one on the front and up one on the rear for the next gear. The bottom ring on a MTB or hybrid triple is about 3:2, needing two rear shifts. Another way of thinking of this is that an MTB triple crank gives you two more shifts off the top and three off the bottom of the range of the middle ring, or effectively a 13-speed bike when paired with an 8-speed cassette.
• You need to pay attention to the derailleur too. Wider gear range means more links of chain wrap and a bigger bottom cog requiring a long cage derailleur.
• Little changes can make a bigger difference than you might think. The switch to smaller slicks took 5% off the top gear of my MTB while improving efficiency - and so the top end is now way too low. I can't make the cassette go any smaller so I'm looking at hybrid / trekking cranks.
• In summary, 3x8 seems like a really sweet spot for go-anywhere bikes, like touring or commuting or hybrid or non-racing MTB. It's a definite improvement on 7-speed. You can get that 20-100 or so total gear range. You get a top gear you couldn't get with a 7-speed freewheel, like cycocommute said, and the bottom cog doesn't need to be a big ugly "Megarange" to get the bottom gear. The shifts are nicely spaced. The 9 and 10-speed systems are essentially adding gears in between the existing range, which makes for more but smaller shifts.

donalson

good read... I'd agree 8spd seems to be a great way to go especially on a longer tour, 6-8spd chains are avl at every walmart I've ever been in... if using similar quality the 8spd stuff has proven to be very reliable (I still know MTB friends that miss the reliability and strength of 8spd XTR drivetrain stuff)

one small advantage I can see moving to 9spd is the 11-36t cassette and then on up to the 10spd would be the 11-42... but in the MTB world a tight cassette isn't important and not having to drop to a granny ring for one small section can be a huge benefit (nothing sucks more then a dropped chain on a technical climb)... I know that at one point Jeff Jones was taking casettes and cutting them down to fit on hope and king SS hubs, wide gear ranges and a strong wheel where the benifits

djb

95 or so is the lowest I would want to be at the high end (what I have with a 42/32/22 and 11-28 eight speed mtn bike setup). The low on this bike is 19.5 and with more than 30lbs or so, and in really steep terrain, it would be nice having one gear lower at times.

I certainly agree with the comment about wanting to have as tight a cluster as possible, as I believe it is even more important with more weight on a bike, as the closer shifts are easier on ones legs, and how often we shift on a touring bike.

I do like having a higher high gear in the 110 range for the fun fast downhill blasts, and/or being able to still pedal on long downhills, but a closer set of low lows is always going to trump the comparatively few times we can go really fast.

Darth Lefty 

I tried those (in my spreadsheet, not IRL - modeling is cheap, testing is expensive). I think the main reason for them is to go with the move to 1x setups and 29er on racing MTB's. The wheels are as big as they can possibly be, requiring lower gears. I didn't like the look of them as much for do-everything bikes because the wide range cassette needs a double front but with an awkward in-between ratio to get the same top gear.

boomhauer

You are going to want a minimum of 90 inches at the top gear for one simple reason.
When on a long flat streach (like rail to trails riding) you will want to mix it up a little.
Instead of being seated all the time you will occasionally want to stand on the pedals.
If you don't have a high enough "high gear" you will find yourself spinning out quickly. Especially if on a paved surface with the wind behind you. (Think Nebraska)
I have an 87" top gear and sometimes wish I had one more high gear.

donalson

absolutely... a 1x10 setup on a MTB is what I pointed to as well... the rear cassette changes gears much more smoothly than even the best front (outside of maybe the internally geared crankset that was for DH/freeride anyway)... I used a 1x9 setup for a while and loved it but because of my heft I had to add a granny ring... this was before the 36 or 42t options on cassettes... just going from a 32 to a 34 made a huge difference... that one extra step to 36 would prob have kept me from going back to a 2x9 setup... I hope to get back into MTBing this spring and may try out one of the silly big 1x10 setups... we'll see lol.

I do recall seeing one guy though on a cat-trike type touring setup in OZ had a 42t out back... the need for the heavy trike and trailer with his load (as I recall it was outback type touring with no good food/water supply) and being unable to use body weight to his advantage on climbs had the gearing make sense for him.

SmallFront

I just filled in the thing, and with my hub, wheel, sprocket, and chainring, it looks like my gear inches are 109.2 at the heaviest, and 26.7 at the lightest.

So, when you people were mentioning 90-100 or thereabouts, I thought to myself "Ouch, I'm not that hardcore", but it looks like my heaviest gear is in the ballpark, which makes me happy (which is sad, lol).

djb

and just to give a rough idea of the top gear on my two bikes, the 95 g.i. has me spinning out at about 50kph or a bit more (at what cadence I have no idea, pretty fast though)
while the other bike with 700 wheels and a 50/12 at 111.5 g.i. spins out at about 70kph (again, no idea of cadence, but pretty much max, whatever that is for me)

to put things in perspective, all the times that I have gone faster than 70k, it had nothing to do with the gearing, ie the bikes were not geared to go anywhere near the speeds, so it was simply by the bike being able to get a good head of steam on its own and letting it run due to the steepness of the hills, good road surface conditions and favorable winds.

As has been written numerous times before, it is very rare to be able to pedal at more than 40kph for more than a brief amount of time (or at least where I live) so hence why the oft touted 100 g.i. is still a fairly reasonable figure to use as a benchmark.

SmallFront

Super, I'm not used to thinking in these terms, but that helps me a bit further.

SparkyGA

19 to 100 equivalent on my Rolhoff. Very rarely use either end of the spectrum during touring.

djb

Thats interesting Sparky, as on every tour I have done on any bike, I have always used the low end of the gearing, 19, 21, 24 g.i. very very often. Obviously it depends on the terrain and just how steep and long hills are, but in really really steep stuff, I certainly would want no less than 19, and a bit lower would be helpful depending on how much weight. We all know all these factors are so variable, but here is an example--last year in Costa Rica with my mtn bike loaded with about 25lbs on rear (no front bags) on the really steep stuff I knew that if I did have another 10 or 15 lbs on board (a tent, cooking stuff, extra food and water would easily get to this) I would have wanted to have one lower gear than its 19.5 (thats with the 22 granny and 28 largest cog in rear).
I'm a reasonable climber and a light rider, 140lbs.

cyccommute 

Too high. I use a 20/34

SmallFront

I guess that's true, but if your lightest gear is light enough, I don't see the harm of carrying that low-rpm gear. In my case, with an Alfine 11s, I can't use a much smaller gear than what is there, because the bike is so long, and if I am going to move the bicycle in under me, while poking uphill, I have to move a bit farther than on an ordinary bike (if that makes sense). With that said, I guess with a derrailleur setup it is possible to fine-tune each of the cogs so instead of a super-heavy cog, you have less variation between the various cogs.

SmallFront

I guess that's true, but if your lightest gear is light enough, I don't see the harm of carrying that low-rpm gear. In my case, with an Alfine 11s, I can't use a much smaller gear than what is there, because the bike is so long, and if I am going to move the bicycle in under me, while poking uphill, I have to move a bit farther than on an ordinary bike (if that makes sense). With that said, I guess with a derrailleur setup it is possible to fine-tune each of the cogs so instead of a super-heavy cog, you have less variation between the various cogs.

Edit: I don't get this: Regardless of how I do it, my reply pops up above the post I'm replying to.

LeeG

If one thinks of choosing gears like gears for an old truck with 75hp it becomes pretty obvious that a gear you can only use going down hill where aerodynamic drag is huge is simply taking up space. It's not like that little engine is going to be pushing the vehicle to higher speeds because it's running at lower rpm. Loaded touring bikes are like little trucks with tiny motors.

bradtx

rwpshaw, The 23" low, most likely, will be okay. Nothing wrong with walking a bike up a hill if need be.

On this forum most touring bikes are assumed to be expedition level rigs capable of toting +40 lbs. of added weight over various terrain. Less weight and/or flatter terrain won't require a deep, granny low.

Brad

Tourist in MSN

We came to a number of similar conclusions. When I set up two of my touring bikes I went with a road triple with a small granny gear and an 11/32 eight speed cassette.

If you continue with this research, two more steps you might consider is to:
- Remove the cross chained gears. I run a triple and 8 speed cassette. But my spreadsheet uses only the 6 gears that are the least cross chained for each chainring. (Big chain ring, only use the smallest 6 cogs, middle chainring, only used the 6 middle cogs, etc.) Thus, my setup results in 18 gears that are actually used, not 24.
- Focus on lots of gears where you will spend most of the time. When loaded down with camping gear, I spend 80 or 90 percent of the time in a gear inch range of 50 to about 85 inches. So, I want a lot of gear choices in that range. My setup with 52/42/24 front and 8 speed cassette of 11/12/14/16/18/21/26/32 provides 7 gears within that range of gears where I will spend the most time. I spend very little time in the lower gears, but those are critical gears to have, the result is that I have wider spacing between those lower gears.



You commented that the big two chainrings on a triple have about the same range as two shifts on the cassette. That would be two step gearing. My setup has one and a half step gearing - meaning that one shift between the middle and big rings is the same as one and a half shifts in the rear. Thus I do not have the redundant gearing that you would have with two step gearing. With a slight change of grade or wind, I commonly will simultaneously shift both front and rear to shift to the next higher or lower gear on the graph.