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Short Wheel Base - why?

Paul Womack2020-10-03 09:51:32

Having been looking at second hand tandems, it appears that once upon a time it was deemed important that tandems have a short wheel base. It appears that Claud Butler is the best known example, but there are plenty of 1940-1960 tandems around with curved or split stockers seat tubes.

And yet there don't appear to be many SWB tandems post 1970.

Can anyone comment on the vices/virtues of a shorter wheelbase, under what circumstances they're desirable.

I admit to find a lugless Claud Butler SWB tandem gorgeous, but I don't want to buy one, only to find out that I've made a terrible mistake!

   BugBear

Paul Womack2020-10-03 10:10:13

Just measured my Claud Butler Majestic Two (common, I know).

Hub to Hub is 165cm or 65 inches.

   BugBear

 

Tim Dowson2020-10-03 22:55:53
Ultra-short wheelbase tandems may only 6" shorter but  handle almost like a solo, with smaller turning circles - good for weaving between cars in urban traffic. They may have been a bit lighter and stiffer than other tandems, especially mass-produced ones. They are easier to handle on a car or on foot, but can be cramped on the back  for any except small stokers (eg children..). Mechanically they can be difficult though as the chain line is problematic with many of the chainrings/sprocket combinations, not to mention positioning a front mech. on a seat tube that is both too vertical and too far forward for the stoker chainring assembly. There can also be very little space for wider tyres or for mudguards. Worth trying before buying..
Mark Silver2020-10-06 14:11:50

To the best of my knowledge, the fashion for curved rear seat tubes on tandems was invented in the early 1930’s by Maurice Selbach, a very innovative London framebuilder. Claud Butlers were pretty well the pre-eminent post-war tandem builder, and their top machines featured the curved tube, and all the best builders of the post war period seemed to offer such machines. Apart from Selbachs and Claud Butlers, I have machines made by Hobbs, Gillott, Higgins, Genner and Holdsworth with it.

The wheelbase of tandems with a curved seat tube is about three or so inches shorter than a straight tubed machine. The pre-war machines often have short top tubes as well, so bringing the distance between the wheels to as short as 58 inches. On one side, the handling of these machines is indeed just lovely, nothing ponderous or sluggish at all. But, and it is quite a big but, the stoker is sitting virtually on top of the rear wheel. So unlike a standard tandem where the riders are between the wheels, the stoker can find this harsh and uncomfortable.

Pre-war, the normal thing was to have cycles with a single gear, either fixed or freewheel. So having the short chain-stays that the curved rear tube allowed was of no consequence, as the chain ran straight. As derailleur gears became dominant, this became a problem. When multiple chainrings requiring a front gear changer became the norm, then the difficulty of effectively fitting such a mechanism to the curved tube likewise became a problem.

Claud Butler went bust in 1956, and at the same time the demand for tandems drastically declined as motor cars became available and affordable. My understanding of it is that relatively few tandems were made in the 1960’s. The curved rear tubes were no longer specially made by Reynolds, so my modern racing tandems are all straight.

I consider the appearance of tandems with the curved rear tube to be most pleasing, though there are exceptions such as some Gitane (French) tandems of the 1970/80’s. If your intended use is going to be single speed or hub gear, and your stoker is happy with a harsh ride (or maybe a sprung seat post), then a short wheelbase is the one for you. But if you want derailleur gears with multiple chainrings, and your partner isn’t keen on having their fillings rattled out then I’d not recommend.

Robert Powell2020-10-06 15:42:43

A plea from all the oppressed stokers in the world, please don't sit Us  on the back wheel, it's bad enough on a normal  Tandem as we are very much closer to the back wheel than the pilot is to the front.
 thanks Rob

Tim Dowson2020-10-15 15:41:13

Mark, I'd be interested to discuss with you a bit more about the Higgins uswb you mention, as I've not previously come across anyone else with one. Could you email me on tim.dowson@blueyonder.co.uk?

Paul Womack2020-10-18 11:11:10

If this forum supported "like" I would give several of them to Mark Silver for a stunningly informative and detailed reply to my question!

Colin Beckwith2020-10-21 22:10:57

There are many reasons why USWB tandems may be considered the zenith of tandem design. Some of the Higgins ones are particularly good - most are lighter and a little better executed than Claud's short wheelbase tandems. Some of the comments are a little wide of the mark. Our stoker is 5' 10" and not cramped on the USWB arrangement. However, our 1951 Higgins has a 61" wheelbase. I think our stoker would indeed notice the loss of 3 important inches to 58! We run 7 speed triple gears with braze on front derailleur. The indexing is ok. The light weight and responsiveness make for really enjoyable cycling. There is the usual upward cycle of light weight - includes lower profile tyres and lighter and less braking requirements. The other massive benefit is that it comfortably goes in the back of many hatchbacks and estate cars. No roof racks or trailers.

23C tyres are run at 90psi at stokers request and comfort is not an issue, I am advised.

On the Higgins , the mounting of the derailleur isn't an issue. Only half the rear downtube is flat. The braze on derailleur position is pretty normal. I've done a replacement and it went ok. 

Like Mark, I think ultra short wheelbase tandems are most pleasing. Maybe environmental imperatives will give them a new lease of life!