Tandems with two sets of gears?

Because the pedals would clash.

Cheers, T i m

Is that really the case Tim? I've looked at several online images of tandem bikes and there would appear to be lots of clearance between the swept diameter of the pedals even allowing for feet/toes overhanging. I could imagine some balance problems with unsyncronised power strokes perhaps. Bob

You can get tandems with independent drive - both driving an intermediate shaft via a freewheel. Though tandems have got longer as people understood how to use big tubes to make a strong frame.

However I suspect different gearing would feel dreadful as the riders went in and out of phase.

I was thinking being out of phase would make the overall drive smoother, especially going up a steep hill, where a normal bicycle is very uneven.

Being 90 degrees out of phase is preferred by some teams - as you note, it makes the load on the drive train components easier. But only some teams - others, like us, don't like it. It feels wrong.

Note that's permanently out-of-phase, ie still pedalling at the same rate. Different gearing would being you in and out of phase, which would be worse.

I think it can be yes.

On our tandem and two riders with feet the same of mine, they might still just miss (I've just checked). ;-)

But then the cranks for the stoker are slightly shorter ...

I just think it would look funny?

Cheers, T i m

Your mind does hop about a lot these days. You almost want something like a reverse differential so that the power can be shared. Brian

Would that not depend on the spacing though? Brian

It could do yes, but the chances are Tandems were smaller (shorter) than they can be today and therefore they were more likely to clash.

Once the precedence was set ... ?

Cheers, T i m

Funny you should say that ... I was looking at a tandem pedal boat the other day where the two crew sit facing each other and pedal in a recumbent style and both pedal forwards driving the same prop courtesy of a small reverse diff. ;-)

Cheers, T i m

My aunt just bought a tandem, and I thought it insane that they both have to pedal at the same speed.

If you do a google image search (sorry Brian), all the results have the pedals nowhere near each other. I would have thought if they were close enough to touch, the two riders would be uncomfortably close together (or comfortably if they were naked).

Quite, they are all about as far away from each other as the length between the bottom brackets will allow with the pedals in sync.

And they used to be like that and even today on my fairly modern tandem, if the pedals were 180 degrees out of sync and with both riders with feet as large as mine, they would nearly touch and could easily touch if you were getting you feet in / out of traps whilst pedaling.

Cheers, T i m

I don't understand that sentence. Did you say something in reverse?

I've never known a tandem like that. Do you have a picture or a link to that model?

Nope. Basically I was saying that if you rotated one crank 180 Degrees to be as you suggested, the rider and stokers feet would probably clash at some point.

Like what?

This is a classic example (not us or our tandem).

Imagine the riders right foot at the 9 o'clock position, her heel could easily be on the middle of the 'o' of 'Thorn' and if the stokers foot was at the 3 o'clock at the same time, that could easily be halfway over the 'h'. Put traps on those pedals and if she was pulling her foot out backwards whilst they were pedaling ...

Cheers, T i m

You said "as far away as the brackets will allow" which would be a very long distance. Didn't you mean as close as they could be without touching the pedals in sync? And the pictures to me look like 180 degrees out of sync would still leave a gap of about a foot (12 inches not a cyclist's foot).

That close.

They should miss with a 6 inch gap as long as nobody's foot comes off.

Also, interesting foot position, I always put the pedal into the arch of my foot, all the power comes from my upper legs, not pivoting at the ankle.

No, it will be the size of the frame.

No, it would be dependant on the size of a frame.

Ok. I have a tandem, I have a foot (or two), I've measured both and told you what I *measured*. So, what you think it looks like is of no consequence.

So you can't see the pictures properly then?

Nope. Measure it up accurately and you will see you are wrong.

And that's why you are asking the stupid questions.

Cheers, T i m

Which can be any size. But the pedals will be precisely frame size apart. So the allow part doesn't make sense.

I've seen the photo you showed me, their feet wouldn't touch.

Yes I can, it's you hat's seeing them wrong.

You even agreed with me by telling me the letter they'd line up with, so they'd miss.

No, that's why my foot doesn't slip off the pedal.