Sidecar outfits on BMW K-model basis

Motorbiking as a hobby that makes lonesome? Not with the sidecar riders: the whole family can tour together and so with ample luggage because a trunk is standard equipment. Outfits date nearly as far back as motorcycles and used to be a normal part of the traffic scene.  After WW II when cars were unachievable a rare mix of vehicles with canvas, plastic and plywood components, manufactured by several small factories, were supposed to satisfy peoples' urgent need for transport , so to one or the other a sidecar outfit seemed to be a more solid alternative. In those days many motorcycles were designed to pull sidecars and were equipped with the respective connection lugs. Suitable sidecars were offered by companies like Steib and could be fitted and taken off quickly. Due to the comparably low engine output, the elastic spoke wheels and the leading links front fork, there was no need to modify the motorcycle for sidecar use. Even then the sidecar enthusiasts had one obvious favorite: BMW.

Left: Still ten years after its debut in 1992 the EML K 1 outfit keeps being an eyecatcher. Especially the K 1 which is known to have little luggage space, improves with a sidecar not only in looks but also regarding its touring capabilities.

BMW keeps being one of the preferred suppliers when it comes down to adapting a sidecar. The procedure itself is different from what happened in the old days because except brands like Ural, Dnepr or Donghai no motorcycle nowadays is certfied for sidecar use. That means instead of the motorcycle manufacturer the sidecar outfit manufacturer certifies for the sidecar capability of the bike and offers model - related constructions.

The subframe

How does such an adaption look like referring to the K-Model BMW? The most important issue would be how to connect bike and sidecar. The early K- Models have a steel bridgetype frame with open bottom part where engine and gearbox serve as integral supporting component. Therefore an additional subframe is necessary, connecting the mainstand mounting lugs, the front engine mounts and the steeringhead, thus closing the open frame with a loop below.

Left: Subframe design by EZS showing the  K100. To the modified steering head the subframe is bolted on. With other manufacturers the subframe is fastened by clamps or braces to the mainframe.

On the subframe itself there are the four sidecar connection points. Suppliers like Peikert offer an ample choice of connection components allowing practically every kind of sidecar to be coupled. Interesting: even a bike like the K 1 featuring a wide area fairing can be modified in this way as demonstrated by Walter in 1989.

Rear suspension

The rear aluminum single swingarm of the K - Models is contemplated by most manufacturers as sufficiently strong. Others like HGT change the original for conventional steel swingarms. Due to the higher overall weight and the heavier lateral stress, reinforced struts are used. In any case the original wheels have to be changed  for car tire rimmed wheels; to different are the demands on solo and sidecar tires. The single swingarm allows fitting wider tires, with the older Monolever swingarm even narrower than the current Paralever- Version. The resulting track difference between front and rear wheel is with most outfits uncritical. Referring to standard wheel sizes for outfits:Using  15"- wheels plus 125 and wider cartires is common practice. Smart- wheel- dimensions are ideal for outfits and are therefore preferred in late designs. The smaller circumference makes for a small ratio- reduction. As the speedometer is triggered by a sensor on the rear wheel it has to be electronically adapted. The leftside muffler design fits the needs of a righthand sidecar outfit and avoids exhaust mods, at the same time keeping the exhaust fumes nuisance for the passenger to a minimum.

Front suspension

The original telescopic frontfork from K 75 to K 1100 would not stand the lateral strain of sidecar use, nor would the rims. That is why an optional use for both solo and sidecar riding with the K- series fork is not possible, except with the below mentioned "leaner"- outfit. Instead a special rim for cartire use is employed in a leading links fork with struts. As an alternative there are hub- center steering designs, for example the K 1200 RS RDS/Cocoon- design by Kalich. Advantage: separation of wheel support-, suspension- and steering- functions. In spite of the wide tires resistance on steering is low. On the other hand these mods are by no means cheap; the necessary single swingarm calls for a modified front brake system, in the case of the Kalich RDS a single brake disc with two four- piston calipers.

Left: The RDS K- 1200 with a basic price of 12300 Euro definitely does not belong into the beginners class. Those who are not scared out will get the best of technology. Hub-center steering is standard, the Cocoon sidecar can be ordered with steering system too and passengers enjoy a seat- width of 32".

`Leaner´outfits

"Soloriding with a sidecar", this could be the motto for what Ralph Kalich offers with his leaner outfits. The idea is not new: already in 1933 there were patents pending for leaner outfits. Basically there are two versions:  1. connecting the sidecar as low as possible to the motorcycle by means of two spherical joints close to the tires in the motorcycle's centerline,the sidecar is kept horizontal. 2. in a different way work suppliers like Side - Bike, where the sidecar leans over parallel to the motorcycle.The Kalich "Swing" outfit based on the  K 1100 RS shown below belongs to the first category. As the K 1100 practically functions as a solobike, the BMW frontfork and wheels stay unaltered. Luckily, you may say because removing two bolts and a plug the Beemer is separated from the sidecar and can be used legally as a solobike. Riding with the leaner resembles soloriding anyway. To the right you can angle down to 45 degrees without problems, to the left you take it down as far as tire adhesion allows, but CAUTION: when turning left the bike leaves by far the normal outfit silhouette.

Left: An unusual view offer leaner outfits like this Kalich-BMW K   1100RS with "Swing" sidecar. Regarding riding dynamics such an outfit is closer to soloriding than to riding rigid outfits. The mods to the bike itself are limited to fitting an auxiliary frame below the frame and in the centerline of the motorcycle. Interesting for families: optionally there can be fitted a second child seat in the boat. So one adult and one child are seated one behind the other. Total price for modification: 5555 Euro.

The “second half of the outfit”

Apropos brakes: of course sidecars have brakes which have to be coupled to the original brake system, normally to the rear brake.Talking about sidecar designs, there is an ample choice; narrow or wide, open or closed, from classic to modern....something for everybody. First you have to think about who is going to ride in the boat. An adult fits inside of course, but according to the boat a child older than three years could have a seat beside or in front of the adult. Compulsory in this case is a cartype child seat or for older children a set of bucketseat safety-belts. In spite of the belts helmets are compulsory which from the medical point of view due to the possible HWS- syndrome is highly questionable. Specs regarding seat width are sometimes little realistic. What do you get from a seat 33" wide if the boat gives you only 30" upper clearance? So don't skip the test seating session if you don't want the passenger to have his arms dangling outside the boat... Up to 300 l trunkspace can be found. Don't need that much luggage? Wonderful, then there is room maybe for an additional tank to improve endurance, a fuel rate of 10 l per 100 km being quite common with outfits. Naturally the size of the boat is related to the outfit's riding characteristics. The narrower the track and lighter the boat the sooner your sidecar will rise in right-hand turns.On the other hand big touring outfits like the Stoye RT by Walter have tracks  of 140 cm and an empty weight of 480 kg. Even if such a bigship is glued to the road in right-hand turns you shouldn't overdo it: the loaded sidecar will push the rear end to the outside of the turn. The outfit freshman should pass a training course anyway. Neither car- nor solobike- practice is of any use if you intent to "keep in line" the most asymmetric of all vehicles. Directions where to apply for training courses you get from the manufacturers of outfits, prices are, depending  on length and performance, from 125 to 420 Euro, training outfits included. Those who want to use their own outfits can contact the ADAC Nordrhein Tel. +49 2259 81158, where a one day course for members is about 85 Euro.

What does it cost to ride an outfit?

This question in the sense of minimum costs Volkmar Prietz from MOTEK tried to answer. He bought an accident-damaged K 100(EUR 1500), a used sidecar, a new subframe and a leading links fork:

  • Subframe € 950,-
  • Leading links fork € 1150,-
  • ”Smart”-rear wheel with adapter € 380,-
  • EML front wheel, used € 250,-
  • Sidecar, used, single seat € 750,-

Overall he managed to stay with this project, i.e. his private outfit, below the limit of 5000 Euro, nota bene: motorcycle included.! Definitely with this price you can't count neither on a flawless finish nor on extras lie tanks etc. Nevertheless remarkable, because at low cost (and a lot of unpaid work) an outfit for everyday use with 90 Hp and shaft drive was created. To have modified the own BMW by a specialist, with an not too expensive sidecar you look at 7500 to 10,000 Euro if only new parts are used. An alternative is to buy a used outfit on K- basis for about the same price; selling your solobike probably you won't have too add more than 5000 Euro.

Where do I get further informations?

On the link page of www. flyingbrick .de you find some outfit manufacturers, more directions and further infos you get with Motorrad Gespanne, the only german outfit magazine. There you can order also  "Das große Handbuch für Gespannfahrer" (general handbook for sidecar riders), a worth to read pocket-book with many informations about chassis technology, modification possibilities and manufacturers.

Translation by Peter Zettelmeyer