Touring - Gearing question.

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View Full Version : Gearing question.


a1rabbit
04-20-10, 08:51 PM
I have an old road bike that was given to me recently so that I can start riding before I get a touring bike. It's been a long time since I've been around bikes and so I'm unfamiliar with how different gear ratios will feel when peddling.

This bike is fine on level and slightly hilly ground, but once I'm going up hill it takes a lot of effort. Now I know I've not ridden in a long time and some of the issue is to do with my body needing to get into cycling shape again. I'm curious as to how much of it is me, and how much of it is because of the difference in my low gears.

I went to Sheldon Browns site and used his gear calculator to the best of my ability, but I have no idea how it relates to real world effort. The bike I have is an old Panasonic (86) DX-3000. The bike I'm looking to get is the Surly LHT, maybe the trek 520.

The DX-3000 has 52 and 42 teeth on each front cog, while the rear freewheel has 14-15-20-24-28 teeth.

The LHT has 48-36-26 teeth on the front cogs while the rear cassette is sporting 11-13-15-17-20-23-26-30-34 teeth.

I can already tell that the LHT will be easier for hills given that the smallest front cog has 16 less teeth than the Panasonic, while the largest rear cog has 6 teeth more than my current.

Below are the generated numbers from Sheldons calculator.



Gear Inches

DX-3000
Teeth 52 42
14 3988 79.1
15 91.5 73.9
20 68.6 55.4
24 57.2 46.2
28 49 39.6

Surly LHT
Teeth 48 36 26
11 119.2 89.4 64.6
13 100.9 75.7 54.6
15 87.4 65.6 47.4
17 77.1 54.9 41.8
20 65.6 49.2 35.5
23 57 42.8 30.9
26 50.4 37.8 27.3
30 43.7 32.8 23.7
34 38.6 28.9 20.9


Given that I don't understand that at all, what will the percentage of difference be?

Thanks!


sunset1123
04-20-10, 10:33 PM
The percentage of difference will be largely on the bottom end, and you will have about a 50% reduction in gearing going from a low gear of almost 40 inches to a low gear of around 21 inches. In real world terms that equates to spinning up all the hills that you are mashing up right now. 21 inches is a low enough gear for me to pull 60 lbs of stuff up 6% grades all day long.

Cyclebum
04-21-10, 03:54 AM
The stock gearing combo on the LHT is ideal for most. If you can spin up a long 6% grade with a load, then your granny is low enough, assuming you're in reasonably good cycling condition. Don't make gearing combo decisions until you are.


TurbineBlade
04-21-10, 05:36 AM
A 39" gear is pretty tough for steep hills with a load. I find that (on my Surly LHT) a double with 38/52 and a 12-32 cassette is good enough. That gives about a 30" low gear.

If you swapped just your current freewheel for a 12-34, you would notice quite a difference going up hills in that low gear. This isn't easy to quantify, but I promise you'll notice. Note that this will probably require a long cage derailleur to handle the big 34t cog (I use a cheapo Tourney Megarange for $20 myself).

I have a 22/32/44 mountain triple crank but don't use it at present because I don't carry a lot of weight at present.

BigBlueToe
04-21-10, 07:54 AM
It's not good to need a lower gear and not have one. I'd put a 24-tooth granny on that LHT. (I did so on mine and I'm happy I did.)

John Nelson
04-21-10, 08:22 AM
Steep hills are hard, no matter what your gearing or level of fitness. Nothing is going to smooth out a steep hill. But it will get less hard as you get into better shape.

jimmuller
04-21-10, 09:04 AM
I went to Sheldon Browns site and used his gear calculator to the best of my ability, but I have no idea how it relates to real world effort...

You got some nice answers but I'm not sure they addressed your question. Some historical perspective might be useful.

In the "old days" (the 70's bike boom) a general purpose 27"-wheel bike came with 52/40 in front, and a freewheel of 14,17,20,24,28 for a gear range of 38 to 100. A more performance-oriented bike might have 52/42 in front. A beginning rider might find 38 not low enough for steep hills even without a load. Any gear above 90 would be used rarely if at all. Most relaxed cruising woud use the range of maybe 60 to 80. When triples and 6-speed freewheels became available the lows might go down to the low 30's or even high 20's. A typical newbie rider would find 38 not really low, but something in the 20's certainly was. A stronger rider coudl take a hill with a 38 that a newbie couldn't. Even a 35 feels lower than a 38, but to a newbie rider it will still feel too high on a steep hill with a load.

By these standards the DX3000 ratios you posted are typical performance numbers. That low will feel too high, load or not. Given enough miles you might think differently, but it's still not ideal for carrying a load uphill. I wonder about the cluster 14,15..., whether it is really 14,17... And I seriously doubt you can push the 3988!

Those Surly gears are hugely different. The high is way higher than anything you'll use except downhill and with a tailwind. More importantly to you, the low will make a giagantic difference. It isn't a matter of percentages but subject experience. With the lower gear your legs will not develop lactic acid burn as quickly. Instead, you lungs will be your limiting factor. Your own ability to lift weight uphill will still be the problem, but at least your legs won't limit your first.

acantor
04-21-10, 09:15 AM
Steep hills are hard, no matter what your gearing or level of fitness. Nothing is going to smooth out a steep hill. But it will get less hard as you get into better shape.

Having an extremely low gear makes a significant difference, and can compensate when one's fitness level is not where one would hope it would be! Over the years, I have installed increasingly lower low granny gears on my bicycles, and with each change, steep hills become easier.

Consider a 22T granny, a size that is widely available. If you can find 20T, and your front derailleur can handle it, consider that instead. There is a huge difference between climbing hills with a 6% or 8% grade, and climbing hills with a 12% or 15% or 18% grade. The hills do exist; in one area where I tour, there is a legendary 20% hill, which so far, I have not attempted!

It is no fun struggling against gravity and wishing for that extra low gear. Some people may warn you that it is impossible to stay upright when riding in an ultralow gear. This is not my experience. I have never felt unbalanced when riding in my lowest gear.

John Nelson
04-21-10, 09:47 AM
The lower the gear, the slower you go, and the slower you go, the longer it takes to get up the hill (i.e., it seems to take forever to get up that hill). Also, at low enough gearing, your speed slows down enough that it starts to become difficult to control a heavily loaded bike (at least for me--the previous poster apparently has no such problem).

jimmuller
04-21-10, 11:03 AM
The lower the gear, the slower you go, and the slower you go, the longer it takes to get up the hill.

There is another phenomenon too which may be my imagination but I suspect is real. This runs counter to conventional wisdom so I expect to get disagreement, but physics supports this argument.

As your pedals swing past top/bottom you have less forward thrust. During that time your total momentum carries you forward, sort of the way a car's flywheel and mass carry it between piston strokes. On the flat you may lose a little speed during this part of the pedal stroke but only due to wind drag. You can actually rest your muscles a tiny bit during this portion of the stroke. On a hill you lose speed due to gravity, the steeper the hill the more you lose. As the hill gets steeper the experience is that you have less time to rest, i.e. the percentage of the time your muscles are working goes up even as nominal pedal load goes down due to a lower gear. As you go slower you have less speed to give up so you can less afford the speed loss, but the rate at which gravity drains it away goes up with the steepness. It has the effect of seeming to give diminishing returns on lower gears. Sure, the load seems to go down but the level of effort required doesn't!

Any mass on the bicycle or rider is more stuff that has to be carried uphill, so it's a bad thing in general. But a gram of rotating mass on the wheels has a small benefit that a gram on the frame doesn't. People don't like to ride with heavy wheels because it reduces acceleration on the flat, and no one intentionally makes a bike heavier. But for some speed/steepness ranges, if two bikes weigh the same but one bike's weight is more in the wheels, that bike will seem easier to get up the hill. At the top of the hill both riders will have done the same amount of work, but one will have had more available resting time (i.e. periods of lower loading) during the climb. Depending on spinning style that could be a benefit. It may even mean the ability to go up on a higher gear. At the very least it is a subject thing that surprises newbies who may end up wondering why that super low g

ironwood
04-21-10, 11:13 AM
What type crankset do you have on the Panasonic? If you have a Sugino or SR crank with 110mm chainring bolt diameter, you might replace your rings witha 46-34 combination. Some of these cranks might also be drilled to accept a granny, and if you can find a proper spindle, you'll have a nice climbing combination.

If hills are too steep, there's nothing wrong with dismounting and pushing your bikie up the hill.

sunset1123
04-21-10, 11:21 AM
^ ^ ^

This is something fixed gear riders have talked about for a long time. I know my first big climb on a fixed gear was an eye opener... I couldn't believe I was climbing the same steep section of trail on a 58 inch gear that I would have previously used a 42 inch gear on my SS. The 'in-between' areas of the pedal stroke just sort of disappear on a fixie.

Developing the smoothest, most circular spin with power all the way around is one sure way to make it up hills without losing speed and progressively having to slow down and gear down.

a1rabbit
04-21-10, 11:37 AM
You got some nice answers but I'm not sure they addressed your question. Some historical perspective might be useful.

Thanks for your reply, explained a lot.



Consider a 22T granny, a size that is widely available. If you can find 20T, and your front derailleur can handle it, consider that instead. There is a huge difference between climbing hills with a 6% or 8% grade, and climbing hills with a 12% or 15% or 18% grade. The hills do exist; in one area where I tour, there is a legendary 20% hill, which so far, I have not attempted!

Wow, a 20 sounds super small! I asked about a 22 or 24 tooth cog at one of the shops here and the guy looked at me like I was crazy. He rides rode bikes. He said he's never needed anything that low for any incline. I told him he looks to be about 25 years old and has probably ridden nearly everyday of his life. Compared to myself who has barely spent more than 10 minutes on a bike in the last 10-12 years! (Until recently). I asked if he's ever toured and carried a large load, he said no. I'm glad they don't stock the bikes I want, I don't think he was being rude though.

sunset1123
04-21-10, 12:01 PM
Wow, a 20 sounds super small!

Because it IS super small. Gears like this can be useful when having to climb up a short wall, or a long grade that just goes on for days... but then, you have to question the 'you just might need it' philosophy a little. You have the responsibility for planning your route. If you are careful, and route plan well, there shouldn't be any 'surprise' 15% grades along the way.

Also, there is no harm in walking. Bicycle tourists seem to feel self-conscious about walking for some reason... and the old argument about how spinning up a hill is always going to be faster than walking... admittedly true. But walking is a nice break for your butt, uses different muscles in your legs, and is a much more upright posture for sightseeing.

Right now I'm running a 34/44 up front... this summer I'll take a shiny new 30/46 up front, and if it gets too steep for that, then my two-foot sightseeing gear is ready to go.

acantor
04-21-10, 01:40 PM
Gears like this can be useful when having to climb up a short wall, or a long grade that just goes on for days...

I wish I had had a 20T instead of a 24T granny when I crossed the Swiss Alps. I began in Zurich, and rode south for two days toward the mountains. There were hills along the way, but nothing that my low 24T-34T gear couldn't handle.

Then I hit the Gotthard Pass. It took me nearly two days of riding to reach the top. Except for a two or three km flat bit near Amsteg, it was UPHILL ALL THE WAY. I was so exhausted when I reached the top I could barely stand. I needed almost a week to recover.

The next chance I could, I switched the 24T granny to a 22T.

acantor
04-21-10, 01:44 PM
I asked about a 22 or 24 tooth cog at one of the shops here and the guy looked at me like I was crazy.

I noticed 24T, 22T, and 20T cogs at Mountain Equipment Co-op two weeks ago.

BengeBoy
04-21-10, 01:51 PM
I just wanted to give you a simpler answer to your original question -- how much of a difference will I feel?

Your lowest gear on the Panasonic is 39.5 gear inches. You can see that the Surly has 5 gears lower than that.

Start riding up a hill on the Panasonic that forces you to shift down into your lowest gear. Keep going for a bit. Now imagine that you can shift down 5 more times.

Another, even simpler way to think about it -- while many folks differ, 20 gear inches is an easy benchmark to remember if you want really low gears on a loaded touring bike. The Surly LHT comes with 20.9 low, right out of the box. You're done.

spinninwheels
04-21-10, 02:06 PM
I thought that when I had my 24x34T I wouldn't need anything smaller, but when I put on my Rohloff, I did.

I have a touring chainring (38), and a commuting chainring (44). Paired up with the 16T rear sprocket, it gives me 1 gear inch smaller than the aforementioned gearing. And considering some of the loads and hills I've tackled, I love it.

The only problem with that small of a gear is that you have to be able to control your balance rather well (I've climbed at speeds of only 4-5 kmph).

spinninwheels
04-21-10, 02:15 PM
If you are careful, and route plan well, there shouldn't be any 'surprise' 15% grades along the way.

I've found that those surprise 15% grades appear in cities and towns more than on highways.

NoReg
04-21-10, 02:22 PM
I think the historical perspective can be misleading to a point because in the past(70s in my case) stuff weighed less, and people would do weird stuff like walk.

On the weight thing, think of oversized tubes, corduras, sleeping bags vs. a blanket or using hostels only; down vs. polarguard, etc... They carried a lot less toys, no expresso makers, loungers, cell phones, locks, and on and on through the endless list. Most people weren't fat. Apparently the steel wheels were an advantage on the uphills, though I guess not if they were pushing...

My mom and dad toured back in the forties, he toured on a single speed she had an English "racing bike" with a 3 speed hub gear, and drops. It was still around when I was a kid. People in Ireland even in the 70s could often be seen pushing their bikes up long hills. Normally when one came across a local cyclist they were walking, since in a given day one spends a lot more time walking up hills than tearing down them.

Also, to add to BB's point. It isn't just about the 5 more gears down, it is also about the narrower spacings (if you so choose) that will allow you to spin at optimal levels over a larger percentage of a trip. My own recipe for touring gears is a low gear, and as many usable in-between gears as possible, and not much in the top end. That is what you will use out touring, though you may prefer more top end when testing the bike, and riding unloaded in general. On the road, unless I have a grade or a tail wind, I don't use the large chainring much at all. Without a load on the road I hardly use the small chainring.

a1rabbit
04-21-10, 03:00 PM
Still getting great replies, thank you!

Is it possible to just swap the stock LHT 26t with a 22t or a 20t? Will the chain and derailer be ok with that?

Are bolt patterns always either 4 or 5 bolt? Or are there other patterns too?

Also, if it's a five bolt pattern, which I think the LHT is, are all brand cogs drilled the same standard distance from hole to hole?

BengeBoy
04-21-10, 03:25 PM
What you need to find out is the BCD (bolt center diameter) of your inner chainring. See Sheldon Brown's site for details. If I'm not mistaken, your inner chainring is probably a 74 BCD (Sheldon explains how to figure this out).

Then, you need to find out if a 20T, 22T or 24T chainring is available in your BCD. You don't have to worry about whether it's 4 bolts or 5 bolts; if it's 74 BCD it will be correct.

As for whether this will work -- probably. What you're concerned about is the difference between the middle chainring (36T) and the inner chainring (20T). You're looking at a 16T difference, which can sometimes get tricky.

Just based on user comments here, I think the Surly LHT is fairly forgiving -- systems with STI shifters can be tricker (in my experience); bar end shifters tend to be more forgiving.

Nothing is free, though -- I think you will suffer some degradation in shifting performance as you increase the size difference between the middle and inner chainrings. I personally have done conversations on several triples that "sort of" worked, but as the differential increases things get steadily trickier. You'll also increase the risk that the chain will drop off the inner chainring entirely when you shift down from the middle chainring to the inner -- you can install a little device called a "dog fang" or "chain catcher" to help prevent this from happening.

If it were my money and my bike, I would leave the bike stock, or ask the shop to swap it out to a 24T inner chainring (if available) and leave it alone. I would be surprised if you really need anything lower than that unless you are pulling stumps, while riding uphill, with a load of anvils on your back.

jimmuller
04-21-10, 05:02 PM
I like the suggestion to leave the bike alone. It already has a huge range of gears.

Here's an interesting figure for you. A cadence of 90 in a 119 gear means you are doing almost 32mph. Using the standard rule that wind drag is proportional to the square of the speed, it takes more than twice the energy to go any particular distance at 30 as at 20. And since you are doing it in less time, the power output required is 3.375 times as great. Most people can do 20 with no trouble. Most can't do 30. But ask yourself, if you can make it to 30 at all, perhaps because you are going downhill or have a tailwind, it is worth the energy to pedal at that speed? Unless you are racing or trying to catch a ferry you might choose to save your energy for when the hill levels off and your speed drops. PP1's point is on-target. You will use the gears you have, but the extremes will be needed only in extreme situations. So why start tweaking the bike now? Wait and see how your riding develops.

a1rabbit
04-21-10, 07:55 PM
I probably won't change anything until after I buy it and get to know the bike and what I need, chances are it will be perfect as is. That's why I was wondering if I can just swap it up if I decide to later, or if I'd have to buy more than just one new cog.

If I would need to buy more than just a cog, such as a new derailer, other cogs, new chain, etc. Then I'd think twice before buying stock components and just get it done at the shop if they are willing to swap parts while they build it.

Another question is this. I might make a thread for it later since it's not to do with gearing.

In Canada the LHT is the same price as the Trek 520. In fact, at some stores the price goes WAY up from the US, most stores want $1799 Canadian for the LHT. We get charged an arm and a leg because we only have one company in Canada that imports the bike. I can drive across the border and get it for 1100, plus taxes, come back and declare the bike, pay duty and Canadian taxes and still stay under $1400 Canadian. Our dollar is on par right now too. It hurts paying so much more for the bike than my American friends.

The Trek 520 is $1399.

I've been talking to the guy at a bike shop that's fairly close to me and he said he'll sell me the LHT for $1399, which is about the same price as if I went to the US and got it.

Given that, should I keep looking at the LHT since the Trek is actually a more expensive bike, typically, than the Surly?

I'll be spending some time this week comparing components on each bike and then let it come down to the ride. I do like the Trek warranty better.

Once I have my money in hand I'll go see him, probably test ride both if he has them in the right size.

The Surly really is a hard bike to get in Canada, most places can't get them, many don't even know the brand.

LHT in Madison
04-22-10, 06:04 AM
On gearing, I have a triple road crankset (52/42/24) and eight speed rear cassette (11/12/14/16/18/21/26/32). I prefer the road crankset, although I rarely use the highest gears I like to pedal with a slow cadence on long shallow downhills instead of coast and it is nice to have really high gears for those rare occasions. This combination gives me 24 theoretical speeds.

I avoid cross chaining to avoid premature wear on the components. I don't use the smallest rear two cogs with the smallest (24t) chainring, don't use the largest two rear cogs with the largest (52t) chainring and with the middle (42t) chainring do not use the smallest or largest rear cogs. This results in a total of 18 gears that I actually use. In my case there is another reason that I do not use the smallest two rear sprockets when I use my 24t chainring, the derailleur does not take up all the slack in the chain.

From smallest to largest of the 18 gears that I use, gear inches with my 37 X 700c tires is as follows: 20.7, 25.5, 31.6, 36.8, 41.4, 44.6, 47.3, 55.2, 64.4, 68.4, 72.5, 79.8, 82.9, 89.8, 96.7, 102.6, 119.7, 130.6. The upshift from the 24t to 42t chainring is not a smooth shift, but I rarely need the lower gears that use the 24t chainring so I don't have to make that upshift very often, so I can live with it.

This gives me everything I want from steep uphills to steep downhills and I have no duplicate gear ratios, there is reasonably good spacing between each of the gears with no large gaps.

I tried a 20t chainring (using a Mountain Tamer Adapter that allowed smaller than 24t on a 74 BCD) but I was unhappy with that experiment.

I am building up another bike right now, I plan to use the same size chainrings and cassette.

spinninwheels
04-22-10, 06:43 AM
I've been talking to the guy at a bike shop that's fairly close to me and he said he'll sell me the LHT for $1399, which is about the same price as if I went to the US and got it.

Is that Mighty Riders on Broadway? Ed is a pretty good guy to deal with.

staehpj1
04-22-10, 07:37 AM
On gearing, I have a triple road crankset (52/42/24) and eight speed rear cassette (11/12/14/16/18/21/26/32). I prefer the road crankset, although I rarely use the highest gears I like to pedal with a slow cadence on long shallow downhills instead of coast and it is nice to have really high gears for those rare occasions.
I too like to have some high-ish gears, but something like a 46/36/24 with an 11-32 cassette shifts much better and at 112.9 gear inches is still plenty high enough for me. I suspect that most folks would be happy with a much lower top gear.

a1rabbit
04-22-10, 01:23 PM
Is that Mighty Riders on Broadway? Ed is a pretty good guy to deal with.

It's not, I tired calling both of their locations about 6 times and I always get their answering machines telling me their too busy or not there. I just gave up. :(

Must be a really popular place, I called during business hours.

spinninwheels
04-22-10, 01:45 PM
There can be quite busy, especially this time of year. I usually just went down there and spoke to Ed in person. I know for a fact that they carry Surly, because I was drooling over a Big Dummy that was hanging on the wall back in 2008. And from what I'd read, Big Dummies were hard to get.

As mentioned, you might be able to get a frame and then build your own bike.