This unusual trike was discovered by Steve in the Racing Tricycles gallery on Flickr:
Note: I have obtained permission from the owner to use these superb images.
The quality of the images is quite exceptional. As one would expect from a keen photographer.
Well equipped with very modern, quality accessories.
Including index gears and dual gear/brake levers.
Such an "aggressive" riding position suggests a keen cyclist. Certainly a tall one. Probably a 24" frame, at a guess. Relaxed geometry and a very pretty colour make for a very attractive and useful trike.
It would be difficult to imagine carrying such a large case anywhere on a bicycle. While a trike takes it easily in its stride. Brackets have been attached to the seat stays specifically to hold this particular case. Avoiding the extra weight of multi-purpose carrier rack and the necessary restraints for such a case. I am not an expert on airflow but angling the case probably helps here. The case sits in the turbulent air from the rider's, flailing legs. So is probably offers quite a low drag despite the increased frontal area it presents. I think we can safely ignore lift. ;)
This Franklin machine is well furnished with wide ratio deraileur gears. So hills are only a matter of slightly greater patience in twiddling a lower gear.
The friction aspect of this 2WD system will depend on the actual details of the layshaft bearings. I think one may safely assume there are a couple of low friction, journal bearings in there somewhere. Chains and sprockets are inherently efficient when clean and well lubricated. Often well up in the high 90s%. Again this is not of cardinal importance on a laden trike. For racing or Time Trialling one might well prefer a Trykit 2WD option. Rider fitness is always the most important factor here.
However, on the back of the sprocket block carrier a single fixed sprocket has been attached. This sprocket drives the separate layshaft via a short chain and another fixed sprocket. A third fixed sprocket on the layshaft drives the other, normally-undriven, trike axle on the right via a fourth sprocket. This final sprocket is presumably a freewheel. To avoid the chains being driven when coasting. Which would instantly wreck the entire rear end! Those tempted to copy such a 2WD layout, on a home-built trike, should remember this vital freewheel.
2WD is a very useful addition to any trike in avoiding severe torque steer. Not to mention a huge reduction in wheelspin in slippery or loose ground conditions. In snow and ice it can make the difference between a fairly normal ride and absolutely no forward progress at all!
The construction details of the Franklin 2WD certainly look competent at first glance. It seems well thought out and the overall finish of construction seems to be of a very high calibre.
I have seen similar layshafts on handicap trikes but not on a trike of this promised level of sophistication. The layshaft itself would have to be adjustable fore and aft. To take out unwanted slack in chain tension. Putting it all back together after routine maintenance might be a bit of a fiddle. Though secondary chain life should be considerably extended over the much harder working, primary chain.
An amplifier has had to be introduced between the handlebar lever and the brake mechanism. Without which the brakes were non-functional as supplied.
Overall the Franklin trike looks an attractive machine.
The shock loads from the rear wheels are all but vertical on the outer ends of the rear axles. The major tendency being for the chainstays to try and rotate upwards around the bottom bracket. Or the rear axle casings to fold up around an imaginary hinge at the centre of the axle due to the weight of the rider. Fortunately the widely splayed seat stays on a trike usually take care of these loads. Almost perfect triangulation being provided by these two simple, straight tubes.
The high cost of importing a new Longstaff with American import taxes and freight charges was considered too prohibitive. In retrospect a Longstaff would have been at least a third lighter but considerably more expensive.
Apparently the brakes were completely non-functional and the wheels built so loosely they were useless as supplied. The bike shop trashed a new pair of wheels because their staff couldn't remove them and literally beat them off with a mallet! The 2WD mechanism would not even hold its position under any pedalling loads. Even the rear sprocket block needed a support bearing after the axle bent. All this had to be repaired or modified before the machine could be used reliably.
An article on this subject, was published in the Spring edition of the Tricycle Association Gazette 2011. Which described the serious faults which made an expensive machine unrideable. It took major repairs and modifications, taking a considerable period of time, before the machine was reliable. It ended up weighing a considerable 45lbs! The investment: $4000! Ouch!
(Note: My bare, roadworthy, 27 speed, Higgins weighs only 31lbs. A roadworthy Trykit racing trike has been built weighing just 20lbs)
A review of the Franklin trike by its owner will appear in the upcoming Bicycle Quarterly. Presumably the Autumn edition 2011.(?)