Tandems of the forum

Wheelset question:
The same way touring bikes at some point had 36 rear and 32 front, would it be acceptable for a tandem (Not likely to ever be madly loaded, even if there may be a front rack) to have 40 rear and 36 front?

@6pt is on 36/36 I think, so 36/40 with modern spokes and rims should be fine I'd have thought.

touring bikes at some point had 36 rear and 32 front

It was 32f/40r in the olden days, but the great unsung technological advance of the past few decades is spokes which have amazing fatigue life compared with those times. Today we design wheels for stiffness, and the strength looks after itself even down to 16f/20r on solo bikes with shallow and narrow rims. My trackdem has 36/36, and it probably has more load on it than a lot of touring rigs :-) It is going to depend on how much dish the rear has, mine is symmetrical but some race bikes use 130mm/10-speed solo hubs which make more demands on the stiffness side of the equation. Nonetheless, some people are happy to use 16/16 old school Shamals and WH-7700s for racing, both of which get past the stiffness hurdle with good bracing angles, the former by using >40mm deep rims and the latter by lateral crossing the spokes. In other words, there's a lot more to wheel design than just spoke count, but if your wheels are stiff enough they are almost certainly strong enough too with modern stainless steel spokes.

Nah, 40 40 for us. Still got some hairline cracks appearing around the eyelets on my 719s after 8 weeks of heavy touring :(

I started with 36 36 on mavic 319s and was getting through a rear rim in a fortnight. But that's cos I'm fat and we like carrying nice things with us.

Hopefully my 48/48s will hold up for another 20 years then.

32/32 on our tandem.

Mainly driven by the Rohloff (I believe there are 36 hole variants out there, but they are rare).

Alpine III spokes from memory.

We are a light team (120kg), and work on travelling reasonably light.

Thanks for all the answers.
Having no certainty as to whether the frame is fine, I'm trying to be economical in the build. Winston checked it, confirmed structural integrity as far as visual inspection allows and re tracked it the best he could without access to appropriate jig (a long one for tandem frames). He suggested I build the bike and see how it feels, then it may need further fine tuning, but probably not... The good old Sheldon Brown technique of running a string between head tube and rear dropouts, that I had a go at when getting the frame back, shows near perfect seat tubes alignment (as far as I could tell, half a millimeter out for the front seat tube, pretty much perfect for the stocker's) and the rear triangle is good as well (Winston mostly had to work on rear triangle and fork, not so much on the bigger tubes parts).
So, as I gather parts I'm trying to use as much from my spares as I can. I have a 1980s / 1990s front wheel, in very good nick, hardly any of the grey finish on Mavic rim braking surface is gone, Shimano 600 hub, stainless steel spokes, 36 of them... I was hoping to use it so I only have to build a rear wheel.
I'll do that for now...

Little spam...

https://www.lfgss.com/conversations/291043/#comment13146831

So we've got access to a touring tandem, and any future tandem purchase dreaming has been oriented towards a more racey option.

I've been offered this frameset and a few bits for free (well, postage) - it should be possible to get it to fit me and the back looks good for the stoker. Problem is it's 26" - worth trying to bodge it to 700c or a non-starter?

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Looks like it's a cantilever brake on the back, so not straightforward, you can't really use a different wheel size unless you can find a way of sorting out the rear brake. Do you have the fork as well?

Yeah i suspect that's the biggest of the many issues. But, y'know, free...

Mavic made an adapter to use 700C in 26" frames, basically a brake arch with extra studs at the right height. Something similar wouldn't be hard to design to take road brakes, in fact I may even have something in the CAD files, but it would be pricey and Dolan frames aren't. Do Conti still make 26x1 Supersonics? That would be pretty sporty without having to mess about, and smaller wheels are inherently stiffer, so you can cut the spoke count for the aeros

If it was me I'd probably stay with the 26" wheels (I'm assuming because it's free you don't necessarily want to spend lots of money) Nothing wrong with them, still easy to get tyres/tubes/rims (despite the popularity of 650B) and you can make strong wheels quite easily.

Shouldn't be too hard to shift if you can't make it work, no?

DEVELOPMENT - donor has some of those Mavic 26"-700c adaptors.

Fantastic news! Sounds like you have a new project

I did 26 to 700c once on a Dawes mtb frame, bit weird, but mostly an unusually high bottom bracket, not sure if ideal on a tandem... (I.e. balance when setting off / stopping)
In my case, I puppy killed canti bosses, and road calipers in rear bridge and fork crown worked just fine instead, any pictures of that Mavic adaptor please, for my education?
Edit... Sorry, just UTFS...
http://urbanvelo.org/mavic-700c-brake-post-adapter/

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So I've decided to pass on the Dawes tandem but it's still up for grabs (cost of postage only) - PM me if you want details.

Progresses of the weekend...
If, because that's what I got, I end up with large rings for the timing chain, would that be a problem (beside the heavier chain, and the fact it might look silly)?

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Allegedly large rings lead to a greater "feel" between riders...

More efficient (see Team GB track bikes)

Great!

Nothing wrong with larger timing chainrings, in fact they last longer, are slightly less draggy and are more stiff feeling as you have less leverage. However the downside is less ground clearance.

That Dolan is available as a full build - looks decent. £1799.

Would you mind posting the links to both the frameset and full build for the Dolan tandem? I promised I'd forward them to a friend but struggling with my phone and dodgy airport internet.