Adventure Cycling Association Forum
Bicycle Travel => Gear Talk => Topic started by: parro on April 14, 2010, 07:35:22 pm
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We are planning a cross country tour (among other tours) and are in the process of deciding on a touring bike to meet our needs. There seems to be much debate about 700c vs 26 inch tires for touring in and out of the country. The other thing we are considering is having the S&S Couplers installed. If you have experience (good or bad)/information regarding either of these, I would appreciate hearing from you. I have done a fair amount of research but personal experience is valuable. Thanks.
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Tires: that's a religious argument for touring in the US. I think it's a matter of how tall you are, how much you are carrying, and what else you wish to do with the bike. I recently installed 700c on my do-everything bike (it came with 26") and it is an ecstatic thing.
S&S: if you want to get them installed on an existing frame, the places I have seen will only install them on steel or titanium bikes. Comotion is of the opinion that S&S should be installed at design time and advises against retrofits. Given the legendary handling of Comotion frames, I am inclined to believe them. Anecdata: I have talked with many people about their S&S couplers because I planning a purchase of a new tandem with S&S. Everyone has expressed only joy with the system. I have yet to hear one negative thing. Again, very second-hand information, so take it with a grain of salt.
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700 vs 26 is indeed a near-religious debate and like you-know-whats I have my opinion too. Personally I think that as long as you are staying in Europe and North America you are fine with 700s. Anywhere else I would go with Shrader valves and 26.
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I have S&S couplers on a tandem. As long as you don't lose the special spanner for tightening/loosening them, you will have absolutely no problems with them. On a long tour or somewhere out of the ordinary, I'd take an extra spanner. Check the couplers each morning before you take off, and they will be completely trouble free.
Bob
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I like 700c in the US and Europe and 26" in SA & SE Asia there are advantages to both. Here is the question. Fully loaded, how much more effort does it take to pedal a 26 inch wheel than a 700c wheel? How much speed do you lose? 2 or 3 mph over 3500 miles adds up.
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I have S&S couplers on three bikes: a Co-Mo single, a Santana tandem, and a Santana triple. Absolutely love them, and they make remote touring much more convenient. Not just the ability to fly more cheaply, but being able to fit in a smaller car, etc.
Regarding retrofits, I highly recommend Stephen Bilenky (http://www.bilenky.com/Home.html) in Philadelphia. I haven't used him for a retrofit on my personal bikes (they are all from the factory), but have used him for other frame work over the years (he just added a kickstand plate to my triple for example). He's probably the leading S&S retrofitter i the USA and does great work. I was just at his shop a few weeks ago and saw several frames in the midst of being "hacked," including a Titanium frame. All looked really well done.
One data point re: 26" wheels: they are much easier to fit into the 26x26 stock S&S case compared to 700c wheels.
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26" tires are easier to find in larger sizes (widths) - in NA and EU. On a single this probably doesn't matter. I'm coming at it from a tandem point of view. One thing to watch with 700c is clearance for fenders. Take a look at Bilenky's site - some beautiful touring singles there. And S&S is always an option there, as with Co-Motion.
If you're looking at a new bike, I can't see why you would retrofit S&S.
The S&S website also shows a list of folks who do S&S - there may be others beyond Co-Motion and Bilenky that do touring singles.
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I like 700c in the US and Europe and 26" in SA & SE Asia there are advantages to both. Here is the question. Fully loaded, how much more effort does it take to pedal a 26 inch wheel than a 700c wheel? How much speed do you lose? 2 or 3 mph over 3500 miles adds up.
With comparable tires, there should be no speed difference between either size. With the same tire, the 26" wheel will accelerate a little faster (spin up faster).
I will concede that the 26" wheel is a little more universally supported. If you ignore the availability of replacement tires, then I think it comes down to what kind of ground you need to cover. I am currently reading a blog about a couple doing a world tour. Currently they are in Mongolia, and conditions are so rough in Mongolia that if it were me, I would want to be riding a 26" wheel set. They are riding a 700Cs and actually blew out a Schwalbe XR tire. At the time, they thought they were stuck until they could ship in a new tire, but the local bike store (more of a market stall that a store) actually carried a 700C compatible tire. Apparently Chinese 28" rickshaw tires fit a 700C rim. I have no idea why you could buy Chinese 28" rickshaw tires.
I still have this notion that there are more road tires to choose from in the 700C size at US bike stores. Of course you can mail order Schwalbe's to fit almost any rim out there, including 27" rims.
I know of one person with S&S couplers. Yes his couplers came loose on a day ride, and yes he failed to check them before he rode. He decided that coupler were a pain. We have pretty much decided that if we can't drive the bikes there, we don't need to tour there. He did get a Bike Friday to take on business trips as it can be set up and torn down much easier than his S&S equipped Co-Motion Americano.
I remember visiting the S&S homepage in the last year. They make couplers that can be designed into any frame type, including carbon fiber. I think the only one you could retrofit was a steel frame since coupler is silver soldered on. I am pretty sure you cannot silver solder to aluminum, and I will confess that I have no idea what you can do with titanium. The S&S people were pretty adamant that you can retrofit any steel bike, and that the coupler will be stronger than the original tubing.
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I like 700c in the US and Europe and 26" in SA & SE Asia there are advantages to both. Here is the question. Fully loaded, how much more effort does it take to pedal a 26 inch wheel than a 700c wheel? How much speed do you lose? 2 or 3 mph over 3500 miles adds up.
I still have this notion that there are more road tires to choose from in the 700C size at US bike stores. Of course you can mail order Schwalbe's to fit almost any rim out there, including 27" rims.
I'm pretty sure that's the case. If you're talking loaded touring on so-so roads, then what you want is at the wide end of what's generally available in 700c, but at the narrow end of what's generally available in 26. On roads typical of the US, you're probably going to be fine with what's fairly widely available in 700c
I know of one person with S&S couplers. Yes his couplers came loose on a day ride, and yes he failed to check them before he rode. He decided that coupler were a pain.
We have couplers on our tandem. Yes you're supposed to check them frequently, but no, we don't check them daily. If properly tightened, they don't just come loose.
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I have couplers on my bike and love them. I only check them about once a week but once they are tightened the first time I've never had to re-tighten them. The only down side is riding in the rain. If you plan to ride in the rain you either need fenders or you have to take them apart to drain the water from the downtube. I rode in the rain once without fenders and found about 4 ounces of water in the downtube.
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The only down side is riding in the rain. If you plan to ride in the rain you either need fenders or you have to take them apart to drain the water from the downtube. I rode in the rain once without fenders and found about 4 ounces of water in the downtube.
A couple of solutions I read about when I was on the T@H tandem forum was putting a super-thick grease on the joint before screwing the collar over it, and the the other one was to put, well, ahem, roll a condom over the whole joint after tightening the collar. Both worked well.
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I've never had water in my tubes from the S&S couplers, and with a tandem and a triple both with couplers, I have a lot of tubes!
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I rode in the rain once without fenders and found about 4 ounces of water in the downtube.
I think I figured out your problem! ;D
The last time I rode in the rain without fenders, I was brushing grit out of my mouth for the rest of the day. It took three washings to get the grit out of my clothing and two showers to get it out of my hair. Road grit, in the rain, without fenders... it's like particulate osmosis. That stuff just gets everywhere!
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I have couplers on my bike and love them. I only check them about once a week but once they are tightened the first time I've never had to re-tighten them. The only down side is riding in the rain. If you plan to ride in the rain you either need fenders or you have to take them apart to drain the water from the downtube. I rode in the rain once without fenders and found about 4 ounces of water in the downtube.
I'm really confused. How do couplers increase the likelihood of getting water in the down tube?
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I'm really confused. How do couplers increase the likelihood of getting water in the down tube?
By themselves, they don't make a perfect seal; so if the front tire is throwing up a constant roostertail of water at the down tube, a little bit can get in, unless you take one of the measures mentioned above.
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I'm really confused. How do couplers increase the likelihood of getting water in the down tube?
By themselves, they don't make a perfect seal; so if the front tire is throwing up a constant roostertail of water at the down tube, a little bit can get in, unless you take one of the measures mentioned above.
Wow. They seem like the teeth ought to mesh well enough to make a perfect seal. But I have fenders, so I guess I haven't actually done the experiment.
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So is there any consensus as to whether 700c actually ride faster than a 26inch? It would make sense. Another thought is that a 26 might actually give you a lower center of gravity increasing stability.
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So is there any consensus as to whether 700c actually ride faster than a 26inch? It would make sense. Another thought is that a 26 might actually give you a lower center of gravity increasing stability.
Neither is true. 700c will have ever so slightly less rolling resistance in the tires, but ever so slightly more wind resistance-- not enough difference to matter. Lowering the center of gravity would require lowering your panniers (which might be marginally dependent on wheel size), and more importantly your body whose CG height is determined by your position and how high the bottom bracket, seat, and bars are. That all starts with the bottom bracket, which has to be high enough to avoid pedal strikes in the turns, regardless of the size of the wheels. The height of the seat follows that, and the height of the bars follows the height of the seat.
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I'm really confused. How do couplers increase the likelihood of getting water in the down tube?
If the threads are properly greased, they don't.
Another vote for the S&S couplers. I have a CoMotion single factory fitted with them and they are a perfect addition to a travel bike. No downside at all except cost and a very minor weight penalty. You do have to check them for tightness every so often but that's no worse than checking that your brakes work before a ride.
As to a retrofit, of course Co-motion recommends you buy a factory-fit frame, they make them and don't do retrofits. I've also heard very good things about Bilenky's retrofits but they aren't cheap.
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Better frames have weep holes in case you get water in the frame. Look down by the lugs. There are ways to get water in a frame, and I would not dwell on the coupler.
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Just one thought from a novice is coat the inside with linseed oil or frame saver and forget about it.
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I have a Bianchi Volpe with 700c WTB All-Terrainasaurus' on them and a Novara Safari with 26" Conti Town & Countrys. I make better progress into the wind on the Volpe, but it also has drop bars, where the Safari has that "butterfly" thing. Maybe it's an illusion, but I feel I "eat up" more road on the 700s. Both the WTBs and the Contis are wide enough to use on dirt/gravel roads, although I would give the T&Cs a slight edge for handling in those conditions. As for 700s being any faster, I did my fastest bike speed ever, downhill on the Safari, (39.7 MPH) and just last weekend working as a medic on my Trek MTB with 26" All-Terrainasaurus' on it, did 32.7 responding to an emergency call at the event we were working.
When we were in NW Russia in '97, our guides all had 700x32 tires and we were on Trek MTBs with their then stock tire on them. The guides had a hard time going slow enough to allow us to keep up. That being said, on their website now, (http://home.onego.ru/~pashkov/index.html (http://home.onego.ru/~pashkov/index.html)) I see equal numbers of mountain and touring bikes. For the Lewis and Clark Trail this summer in South Dakota, I plan on using the Volpe again.
Ride safe,
Hans
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I think the case for 26" in certain parts of the world is a little too anecdotal. It seems reasonable and is probably basically true (I've lived in Asia, and you see way more 26" and odd 650-ish sizes than 700), but I have to wonder how true it really is in practice. Seems like half the travel journals I read on CGOAB describe having to order tires no matter where they are. When cheapo tires are picked up locally, they are often described as unsatisfactory and short-lived.
It would be really interesting to do a proper survey of tire use and availability in Asia, South America and Africa
Anyway, the issue didn't stop me getting a 700c (aka 29er) "expedition" touring bike.
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Add another yes vote to the S&S couplers. My wife and I have them on our Co-Motion NW Tours and have had no issues so far; of course, we've only had the bikes for about 1 1/2 years, but....... they've been to Europe twice now. ;D
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I suppose I could search for the website, but can anyone tell me what S&S couplers are? Sounds kinky!
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(http://www.sandsmachine.com/p_ssbtc2.jpg)
It's a very solid tube joint that can be assembled and disassembled any number of times. With these in key places on the frame (normally one at the rear of the top tube and one near the bottom of the down tube), this bike:
(http://www.sandsmachine.com/p_com_r1.jpg)
fits into this 26"x26"x10" suitcase:
(http://www.sandsmachine.com/p_sns_c1.jpg)
(See http://www.sandsmachine.com/ )
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On the day I got water in my downtube I was on a supported tour. I had just crested a summit and it started to rain, hard. It was about 3 miles downhill to the rest stop so I rode as fast as I safely could. I was throwing up quite a roostertail. No one was expecting rain so we were without rain gear or fenders. Lets just say me and the bike were wet and dirty. After that I got fenders for the bike. That ended the problem.
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One thing that doesn't seem to get mentioned in the 26" V 700 debate is weight, the smaller wheelset and tyres must give a saving of some kind.
Damn. Now I'm going to have to go and buy a set of accurate scales to check this out!
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26" gives a slight reduction in weight and slight increase in rolling resistance, but not enough to matter. The slightly better spoke bracing angle on the 26" does make for a stronger wheel with the same number of spokes though.
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This 700C vs 26" is an interesting one to me. I have a unique position in that my bicycle can take 700C and 26" because it has disc brakes. I have two custom wheelsets, that are roughly the same build, although the weight nod goes to the 26" wheelset because of lighter hubs and lower spoke count. Using the same tires originally (Panaracer t-serv), the 700C wheels give me a higher average speed on my daily commute, ~13.8 MPH vs ~15.6 MPH.
Now this is purely anecdotal and not something everyone can try on their own steeds. But I know what the wheels do for me on my bike.
Similarly, Co-Motion gives 700C the speed advantage in tests, although now I can't find a link to the article that was on their site.
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Fitting my bike into a suitcase sounds very appealing compared to the cardboard bike box I've got it in right now ready to fly out in a couple of weeks. But 23 kg would still be 23 kg whichever way you pack it.
On the tyre size issue, isn't what you call a 700c wheel the same as a 28 inch? What does 700c refer to? After reading 'The Man who Cycled the World' I can see some of the advantages and disadvantages. He rode on one of the best bikes around - Koga Miyata - and still his double-rimmed back wheel - a 28 inch - broke spokes and had to be re-built at least twice during his trip. Maybe gave him a few more miles per pedal, but evidently a weaker wheel when loaded it seems.
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On the tyre size issue, isn't what you call a 700c wheel the same as a 28 inch? What does 700c refer to?
Yes, 28" is the same size as 700c, and the MTB world calls them 29". There used to be a 700A, 700B, and 700D too, but the common one left now is 700C. They all had the same outer diameter of the tire (close to 700mm), but to get there, the smaller cross section tires took a larger-diameter rim. 700A had the biggest diameter of rim, with a bead seat diameter (BSD) of 642mm. 700B had a BSD of 635mm, and 700D had a BSD of 587. Today we use the same C rim size with a 622mm BSD for all of them, so you can use a range of tire widths on the same wheel.
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After reading 'The Man who Cycled the World' I can see some of the advantages and disadvantages. He rode on one of the best bikes around - Koga Miyata - and still his double-rimmed back wheel - a 28 inch - broke spokes and had to be re-built at least twice during his trip. Maybe gave him a few more miles per pedal, but evidently a weaker wheel when loaded it seems.
He blamed the wheel breakages on a combination of rim brakes and over tensioning of spokes. He also said that if he was doing something like this again, he'd use disc brakes.
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Since the discussion includes S&S couplers, I should also note that 26" wheels are way easier to pack in a standard S&S 26x26x10 case. 700c fits, but you have to deflate the tires usually and the wheels take up more room in general.
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Just came back from a ride on my 26" Safari; The 700 Volpe is in the shop getting ready for next week...I think. Reports (from friends in the area) are, due to flooding last month, that the county road on the L&C 7 miles south or Marty is still out, meaning we may have to divert on dirt roads around or carry the bikes over. (We have a SAG van, so we are not riding fully loaded. The van will have to divert around.) Given that change, should I stick with the Volpe, or take the safari instead?
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After reading 'The Man who Cycled the World' I can see some of the advantages and disadvantages. He rode on one of the best bikes around - Koga Miyata - and still his double-rimmed back wheel - a 28 inch - broke spokes and had to be re-built at least twice during his trip. Maybe gave him a few more miles per pedal, but evidently a weaker wheel when loaded it seems.
He blamed the wheel breakages on a combination of rim brakes and over tensioning of spokes. He also said that if he was doing something like this again, he'd use disc brakes.
Unlikely. If the stresses from rim brakes were the cause of broken spokes - the front ones would break also (most of the braking in extreme stops is on the front) - it is always the back ones. The combination of driving forces, too much weight, uneven tension from wheel dishing, and not enough spokes is why tourists have broken spokes on the back. Spoke quality and hub design make a difference also. The best modern wide based cassette hubs (135mm) with properly rounded holes and slight inward angles on the flanges combined with 36 quality spokes and an expert hand-build will stand up well to touring loads up to about 150 pounds on the rear wheel. Above that, expect broken spokes or go to a 40 spoke tandem wheel.
There may be some slight truth to the theory that mountain bike rims (26) are "better braced" than 700's - but that also means that the spokes are leaving the hub flanges at a more acute angle - which contributes to breakage. Mountain bike hubs at 135mm spacing have a slight advantage in dishing over 130 road hubs. It's easy to spread the rear forks on a steel frame to 135.
As has been mentioned by other posters - if the rim construction and tire construction is the same between 26" wheels and 700C wheels - the circumference will be less and the spokes shorter for a slight overall weight advantage for the smaller wheel. The inertial weight advantage will be very slight as the smaller diameter wheel also has accelerate faster to reach the same road speed. The very low hub rolling resistance will be slightly higher for the smaller wheel at any given speed and the smooth surface rolling resistance of the tires (assuming identical construction) should be identical. On rougher surfaces the larger diameter tire should have a slight rolling resistance advantage. All taken together - the overall difference is so small that it hardly matters on a touring bike.
What makes the difference is that the tire construction is almost never the same. It is very difficult to find really lightweight thin tread 26" tires in a 1 1/4 (32mm) or 1 3/8 inch (35mm) size. For that matter it is fairly difficult to find tires of that description in a 700c. So what happens is that the 700c tourist ends up buying a narrower tire that needs to be pumped up harder and the 26" tourist gives up and buys a wider tire that has much thicker than optimal tread thickness and doesn't roll as well at the appropriate pressures.
My opinion is that the ideal touring tire for lighter tourists and loads is 32mm (save the 28's for credit card touring only) as the rider and load gets heavier 35mm tires are ideal. 38mm is only for the heaviest loads or if you expect to be on dirt a lot. The really wide knobby mountain bike or cyclecross tires are for dirt only - way too slow to make mileage on a tour and all wrong on pavement.
I was talking with two young men from England yesterday on the American River Bike trail in Sacramento, California. They were on their second to last day of a cross-America tour. With over 3,000 miles on their clocks they had each broken one spoke (32 spoke wheels) and worn out their rear 32mm tires (and replaced them with 28's). All their camping gear was on the back wheel and they were lightweight riders. If they had used front lowriders, and rotated their tires halfway through, they might have done the entire tour trouble free.
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He blamed the wheel breakages on a combination of rim brakes and over tensioning of spokes. He also said that if he was doing something like this again, he'd use disc brakes.
Unlikely. If the stresses from rim brakes were the cause of broken spokes - the front ones would break also (most of the braking in extreme stops is on the front)
+1. Disc brakes put a lot more stress on spokes.
About the spoke-bracing angle though-- that makes the wheel a lot stronger, and is why tandem wheels are so much stronger, and famous wheel builder Peter White (http://www.peterwhitecycles.com/wheels.asp) insists that 36 spokes are virtually always enough for a tandem when the wheel is built right. I found out about him on the tandem forum where everyone raved about his trouble-free 36-spoke tandem wheels, including for loaded touring. To get that wider spoke bracing angle though, tandem wheels use 145mm or 160mm dropout spacing, not 130 like road bikes'; so you can't just put a tandem rear wheel in a single road bike or even a touring bike. Decades ago when tandems' rear dropout spacing was 135 or less, they had a lot more wheel trouble even with 40 or 48 spokes. To further press the point about bracing angle: For the last 9 years, Santana has been selling 16-spoke tandem wheels which have proven to be very reliable. The dropout spacing is 160mm, and the spokes from the right flange go to the left side of the rim, and vice-versa, to improve the spoke bracing angle.
(http://www.santanatandem.com/images/Exo%2710-600.jpg)
The inertial weight advantage [of the smaller 26" wheel] will be very slight as the smaller diameter wheel also has accelerate faster to reach the same road speed.
No, it's the same number of feet per second. RPM itself is not the issue. The myth of rotational weight is exploded in this (http://biketechreview.com/reviews/wheels/63-wheel-performance) wheel-science web page though. You can see for example in the middle of the first table that the wattage savings in the uphill portion of a training ride if you cut the front wheel's rotational inertia in half (an absolutely huge reduction!) is only 0.004%. IOW, it doesn't matter.
The very low hub rolling resistance will be slightly higher for the smaller wheel at any given speed
very low, yes-- totally negligible.
and the smooth surface rolling resistance of the tires (assuming identical construction) should be identical.
It's a hair higher with the smaller tire, due to more energy being wasted by the slightly sharper bend at edges of the contact patch; but yes, the difference is too small to matter.
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He blamed the wheel breakages on a combination of rim brakes and over tensioning of spokes. He also said that if he was doing something like this again, he'd use disc brakes.
Unlikely. If the stresses from rim brakes were the cause of broken spokes - the front ones would break also (most of the braking in extreme stops is on the front)
+1. Disc brakes put a lot more stress on spokes.
About the spoke-bracing angle though-- that makes the wheel a lot stronger, and is why tandem wheels are so much stronger, and famous wheel builder Peter White (http://www.peterwhitecycles.com/wheels.asp) insists that 36 spokes are virtually always enough for a tandem when the wheel is built right. I found out about him on the tandem forum where everyone raved about his trouble-free 36-spoke tandem wheels, including for loaded touring. To get that wider spoke bracing angle though, tandem wheels use 145mm or 160mm dropout spacing, not 130 like road bikes'; so you can't just put a tandem rear wheel in a single road bike or even a touring bike. Decades ago when tandems' rear dropout spacing was 135 or less, they had a lot more wheel trouble even with 40 or 48 spokes. To further press the point about bracing angle: For the last 9 years, Santana has been selling 16-spoke tandem wheels which have proven to be very reliable. The dropout spacing is 160mm, and the spokes from the right flange go to the left side of the rim, and vice-versa, to improve the spoke bracing angle.
(http://www.santanatandem.com/images/Exo%2710-600.jpg)
The inertial weight advantage [of the smaller 26" wheel] will be very slight as the smaller diameter wheel also has accelerate faster to reach the same road speed.
No, it's the same number of feet per second. RPM itself is not the issue. The myth of rotational weight is exploded in this (http://biketechreview.com/reviews/wheels/63-wheel-performance) wheel-science web page though. You can see for example in the middle of the first table that the wattage savings in the uphill portion of a training ride if you cut the front wheel's rotational inertia in half (an absolutely huge reduction!) is only 0.004%. IOW, it doesn't matter.
The very low hub rolling resistance will be slightly higher for the smaller wheel at any given speed
very low, yes-- totally negligible.
and the smooth surface rolling resistance of the tires (assuming identical construction) should be identical.
It's a hair higher with the smaller tire, due to more energy being wasted by the slightly sharper bend at edges of the contact patch; but yes, the difference is too small to matter.
Great informative post, what is your thoughts on mags compared to spokes regarding momentum?