Folding Bikes - Gear range for loaded touring

I wonder what gear range would be a wise choice? ATM I have a S-A 8-sp hub gear with 34-105GI. I have much better than average fitness (eg my RHR is 40bpm atm) and have absolutely no problem riding up big mountains; I just wonder if I should do something about the gearing for loaded touring? I am aiming for less than 15kg load. The bike is also 15kg (modded Raleigh 20) and I am 75kg. I commute about 56km every day of the year with this bike and a smallish load, perhaps 8kg. The tour is in Tasmania, 3 weeks of daily hills.

Please tell me I'm daft before it's too late...

Ooooh. A math problem!

You are comfortable with 34 GI with a total package of 98 kg. Your total package on tour would be 113 kg or 15.3% more. I would think that as long as the Tasmanian hills are no steeper than your "calibration" hills then if you reduced your lower gear by 15.3 percent it would all come out even. So you'd want a low gear of 29.5 GI.

So much for the math. The quesion of how much of that 15.3% you've got in margin is something only you can answer. You are close enough, maybe you can do it. But, you are going on what I assume is a vacation. The difference between "can do it" and "enjoy doing it" is all the difference in the world.

Personally, I would rather not subject my knees to a lot of punishment. If you can easily do a chainring, rear cog swap you could shift your range down 15% or more.

If Google earth is any indication, you really are in for some hills!

Speedo

I wonder what gear range would be a wise choice? ATM I have a S-A 8-sp hub gear with 34-105GI. I have much better than average fitness (eg my RHR is 40bpm atm) and have absolutely no problem riding up big mountains; I just wonder if I should do something about the gearing for loaded touring? I am aiming for less than 15kg load. The bike is also 15kg (modded Raleigh 20) and I am 75kg. I commute about 56km every day of the year with this bike and a smallish load, perhaps 8kg. The tour is in Tasmania, 3 weeks of daily hills.

Please tell me I'm daft before it's too late...

A typical touring bike will have gears that go down to the low 20s in gear inches.

I guess how much you want to lower your gearing will depend on whether you mind coasting downhill. My choice would be to be a little more cautious on a tour far from home.

Although I suspect that you might be limited by the SA-8 hub design and the possible combinations with your front chainring. Is it the case the the SA-8 hub has a 21 tooth cog? What is the smallest chainring you can fit on your crank?

you are going on what I assume is a vacation. The difference between "can do it" and "enjoy doing it" is all the difference in the world.
Speedo
Good point!:beer:

I would use 18" to about 80" but then that's just me!!

This is some good discussion. Vacation--my advice have the lower gears, i.e. lower 20s as the previous posters have pointed out

I have discussed these in the Downtube thread. Search my name.

Enjoy Tasmania. It's special.;) Go lite.

Yeah, I am limited (or almost completely stuck would be a better description) on the gearing. The front is the standard Raleigh 46T crankset, a change is hard what with their 26TPI bottom bracket cups. The back is already at the max size of 25T.

Nice math approach Speedo. That puts it completely on firm footing wrt what is possible. I hardly ever use the 34GI gear, so I am imagining that gear is "spare".

Good point of "can do it" and "enjoying it." Actually I enjoy pushing hard, but that would not be for the whole day, every day.

And let me reveal another crucial detail: My wife is also coming. Her fitness is sorta far behind mine, but she has been training very hard for this tour. We already know what hills we are going to face thanks to Google E; I have got the number for every day in terms of where the serious climbs for each day start, what the length and gradient of the climbs are. So at least mentally we are prepared, which I am imagining might be 50% of the total package? The other half being fit enough to actually do it.

Her bike (Yeah, rebranded Dahon Helios) has currently a gear range of 26-82GI. The plan is I will carry most of the stuff, she will only be carrying personal clothes, lightweight sleeping bag etc. She has been training with the loaded panniers for 3 weeks already. We started of with a 52T ring, then I got that down to 42 which was stupidly low. Then I put on a 46, which on a 10% slope she handled easily, and she tells me she virtually never gears down to the lowest one. So now I stuck a 48T on there.

I am so uncertain...

It sounds like your wife is reasonably dialed in. I would recommend that you carry along that 42 on the trip until you see how she is actually performing in the hills. Making sure your wife is happy is key. If Momma ain't happy, ain't nobody happy. You could mail it home to yourself if she doesn't need it.

I'm going to go out on a limb and make an actual recommendation: Take your 20 as it is.

I don't know Tasmania, but all the big climbs I've ever done have the following characteristic: you have a miles long grinding climb which is hard, but tolerable, and then you get a shorter (mile or mile and a half) kicker at the top. With your described fitness level I would bet that you have no trouble on the run up climb. Worst case you will have walk the kickers at the top.

I would guess that you can bring another bike, but your 20 is the "other love of your life". It would suck to leave her at home. For you I think the trade off is that the pleasure of bringing your 20 on tour will outweigh the pain of potentially hooffing it through the tops of the passes.

Speedo

Speedo, heheheh, you're very perceptive. I have also been thinking I will simply load another chainring on her crankset and derail by hand if the necessity comes.

Here is my Raleigh Twenty, prepared for the tour:

http://members.iinet.net.au/~jdekter/Raleigh20/twenty final.jpg

Another bottle cage still to be mounted, and I will probably set the stem to the highest position. A coupla days before zero hour I will also put a Big Apple on the rear; I took it off and put a cheapie on for commuting - it wears too quickly.

Jur,
I know it's too late for this tour, but you can always purchase the Phil Wood cups and see if you can source a UN72 bottom bracket. I know it's a little more expensive, but cheaper than going with the all Phil Wood set up. Have a great tour,
Juan

Thanks Juan. I have considered the Phil Wood option, and in the end the desite to keep the original crankset won over. So I guess I am realllllly stuck ;)

Plus after this tour I will be building up a Swift folder, so perhaps the R20 will suffer a bit of cannibalising and fall back on some of the original parts, all of which I carefully kept.

(Carefully kept = lying around somewhere in my garage on various horizontal surfaces)

Go as low as you can go with your system. There will always be some hill late some afternoon that will hurt if your gears are too high. There are gearing systems that can give you gears in the single digits. Mostly for sand, snow, and hill climbs. Not for tour. With a loaded bike and a 14% grade you are just more efficient simply walking up that part. I have bought 4 successive tourers and now have a 22-32-44 in front and a 12-34 nine speed in back. Find if parts sold in Aussie land will work with your bike.

Thanks Juan. I have considered the Phil Wood option, and in the end the desite to keep the original crankset won over. So I guess I am realllllly stuck ;)

Plus after this tour I will be building up a Swift folder, so perhaps the R20 will suffer a bit of cannibalising and fall back on some of the original parts, all of which I carefully kept.

(Carefully kept = lying around somewhere in my garage on various horizontal surfaces)

Jur,
My Twenty was my first project bike. Before it, all I knew how to do was to change a flat. If I found another one, I would be sure to keep all the parts I took off. Like an idiot, I tossed most of the parts, not thinking I might want to use them again. Oh well, live and learn.
Juan

It sounds like your wife is reasonably dialed in. I would recommend that you carry along that 42 on the trip until you see how she is actually performing in the hills. Making sure your wife is happy is key. If Momma ain't happy, ain't nobody happy. You could mail it home to yourself if she doesn't need it.

I second that motion!

So you can't fit a chainring smaller than 46t on the R20? Bummer.

Speedo, heheheh, you're very perceptive. I have also been thinking I will simply load another chainring on her crankset and derail by hand if the necessity comes.

This sounds like a good idea, because you ride all the time your body has adjusted to the constant joint stress where as if your wife keeps pushing for 3 weeks she may suffer. I know I did initially with our hills.
Goodluck and I hope you enjoy your visit to Tassie.