CONSTRUCTION DETAILS OF TANDEMS.
Nearly all makes adjust the front chain by having the front crank-hanger bracket and bearings made eccentric, so as to take up the slack of the chain, and a few of the makers have adopted this same system at the second crank-hanger bracket, others varying this by adjusting the rear chain at the rear fork ends as usual. The makers who furnish their tandems with the chains both on one side claim that this type of construction is the best because in the event of the frame becoming bent or out of line the chains will more readily adapt themselves to the new conditions. Those who use a chain on both sides say that the power is transmitted more evenly by this method, and that therefore the frame is not so liable to be sprung out of line as where the pull is all on one side of the frame. However this may be, a majority of the makers put both chains on one side, and the makers of the National (who have a combination of both systems) claim that their three-chain system applies the power evenly through the frame instead of on one side, and that this system relieves the stress upon the bearings by making both sides do the work instead of allowing one side to run light, and that the use of three chains overcomes the stress of the usual long chain, and permits the riders to run the chains as loosely as on a single wheel without danger of either chain jumping the sprocket when riding fast. Racing men who have ridden the National say that there is no sway whatever in the wheel, and that it gives a more even and steadier pace than is usual in tandems and is easier to hold and follow. The idler used on the National is an ingenious piece of work, being a double ball bearing, the usual idler in ordinary construction being an open plain bearing on a stud. There is practically no strain on this idler, as the pull of one chain is offset by that of the other; it is not used to hold the chain down, but serves as a sort of loose pulley connection.
WOLFF-AMERICAN TRIPLET.
The only juvenile tandems made are those made by the makers of the Elfin. They are a part of their regular output, and are made in both diamond and combination styles, the heights of frame running from 16 to 22 inches, and the weight from 28 to 35 pounds. The little gears run from 50 to 67 inches. These little Elfin tandems are distinctively juvenile in all their parts, the head, saddles, pedals, handlebars, grips and tubing are all miniature in size, making its measurements as nicely proportioned as a regular adult’s wheel, and the name “Elfin” has been well selected for the product. These little tandems are sold for $50.
Tandem chains are very much lighter than in former years, some makers using as light as 3⁄16 chain all over, but the majority of them use 3⁄16 for the front chain and ¼-inch for the rear chain. The combination tandems on the market are furnished usually with 20 or 22-inch front frame and 24-inch rear. Diamond frames are furnished either in 22 or 24-inch frames, 22-inch frames being in line with the prevailing fad of low frames, and therefore the most popular. Gears run from 80 to 120, the popular stock gear usually furnished being about 84, with 7-inch cranks.
On the [Wolff-American tandem] the diagonal stay carrying the seat-posts are not raked at the same angle with front fork and head. The middle steering post, however, is raked at the same angle as the head, thus permitting the rider in front to have more room for a better position in pedalling. The Wolff-American tandem is fitted with a very powerful rear brake. It consists of a lug which is brazed in the centre and underneath the main upper tube in front of the rear rider. From this lug a lever is hinged; this lever carries an adjustable wire rod to the brake spoon which is hinged on the bridge between the rear forks. Pulling up on this lever draws a powerful spoon against the rear tire. One of the advantages of this brake is that it does not affect the steering as a handlebar brake does.
The “World” tandems have an extra lower chord running from the front diagonal stay to the rear diagonal stay, which is in turn braced by two braces running from it to the lower chord of the frame. On the Dayton tandem an extra tube is carried from the head underneath the main upper tube and which intersects the diagonal tube and runs from there to the rear crank-hanger bracket. This construction produces a very stiff and rigid frame. On the Stokes convertible tandem an extra tube runs from the upper part of the head intersecting the front diagonal stay and the rear steering tube and is then brazed to the lower main tube. The Eldridge diamond tandem carries an extra tube from the front diagonal tube to the rear crank-hanger, and this same method of construction is followed in the Clipper convertible tandem.
In the Niagara tandem the top tube is paralleled by a tube placed about six inches below it, running from the front diagonal tube to the rear diagonal tube, the rear steering post intersecting it. On the Winton tandem the upper main tube is not continuous, there being an open space between the front seat post and the second steering post, this being braced, however, by a tube which runs from the front seat pillar, bracing the middle steering post, and running to the crank-hanger bracket. The Geneva and the Demorest are of the same construction.
The Columbia combination and diamond frame tandems are of the same general design as the 1897 models, except that it has been deemed advisable to have the frame connections of the external joint style instead of making them flush joint, as last year. On the diamond frame they run an extra tube from the lower part of the head, and this is connected to the front diagonal tube at a point about eight inches above the crank-hanger. This tube then runs horizontally, intersecting the second steering head, and ends at the rear diagonal stay, from there, however, a second pair of rear forks running to the back stays. This same construction is followed out in their combination frame, with the exception that the front part of the frame is of the double loop pattern, as in their single wheel. The Iroquois tandem has the same open construction at its front diagonal and second steering post as the Winton, heretofore mentioned.
WOLFF-AMERICAN
TANDEM.
The Tribune tandem has an extra tube, which parallels the main upper tube. On the Pierce double diamond tandem an extra tube runs from the middle of the head and intersects the front diagonal, and is brazed to the rear crank-hanger. The Henley diamond tandem has the upper main tube paralleled by an additional tube, which runs from the lower part of the head to the rear diagonal stay. On the Andrae tandem the chain adjustment is effected by means of eccentrics in both hangers, thus doing away with the slot in the rear fork ends, which has a three-eighths-inch opening, in which the three-eighths-inch axle is fitted perfectly, so that the rear wheel is perfectly centred at all times, even under the greatest strain. The method of placing an extra tube running from the top, or near the top, of the front diagonal stay to the crank-hanger bracket is in almost universal use, so that it is easier to name those who do not employ this method than to name those who do. Among the notable exceptions to this method of construction are the Columbia, Niagara and World.
Very few of the makers of tandems have made any great changes in their ’98 construction, the majority of the tandems shown being their ’97 product, somewhat improved in detail only. Handle bar fastenings are about nearly divided between the old-fashioned pinch bolt and the newer idea of internal clamp fastening. Some difficulty has been experienced in previous years in holding handlebar stems and seat posts securely in place on tandems, many of the makers not having used connections heavy enough and stiff enough to withstand the double pull that a tandem gets at these points, and the purchaser of the 1898 tandem should look well to the construction at these points before purchasing.
CLEVELAND
TANDEM.
The tires used on tandems differ somewhat from the ordinary tires in use, being somewhat thicker and heavier, and are usually stamped “Tandem” where they are branded. The average size in use is about 1¾ inches, but some of the makers furnish them as large as 2 inches. The dropped crank-hanger fad does not prevail to so large an extent in tandem construction as in the single construction. Sizes of tubing used show a slight increase in diameter over that used in making single bicycles. The majority of brakes fitted on tandems are of the lever and spoon pattern, working on the front tire. Hubs, rims and spokes are made heavier, and the three-plate crown seems to be a popular one among the makers who use the double-plate crown on their singles. The Adlake has a quadruple-arch fork crown.
On the World tandems and multicycles the crank-hangers are hung in a swinging bracket, which are held in place and adjusted forward or backward by a set screw having lock-nuts to hold it in place, and which is connected back of the hangers to the lower main tube of the frame.
On the Geneva tandem the front bracket is a special device of theirs which consists of a tubular bearing barrel sliding in an oblong hanger fastened with set screws in front, with caps over the ends secured to hanger with lock-nut.
The Demorest tandem has the rear seat and pedals very much higher than the front seat, so that the rear rider can look over the head of the front rider. It appears to be a revival of a similar type that was made last year by the Crescent people, although it is not carried to such an extreme height as it was on the Crescent. Wheel-bases run from 65½ to 75 inches, the average wheel-base being about 69 inches. Weights run from 40 to 50 pounds, the average being about 44½ pounds.
TINKHAM CAB.
On the [Defender Midget] the seat post is inserted into the handlebar clamp, this doing away with the necessity of an extra fastening. The makers of the National, the Defender and the Dayton make single steering tandems. The Peerless is furnished with an automatic rear hub brake. At the Philadelphia Cycle Show was shown a chainless tandem, having on it a [Hildick Spur Gear], which has already been described by us in the article on chainless bicycles for 1898. The great points in tandem construction are weight, rigidness, ease of draft, length of wheel base, steering and the proper position of the riders. Nearly all of these points have been conquered by the makers, so that the art of tandem cycle building has well-nigh reached perfection.