• Welcome to the BMW R18 Forums. Member registration disables ads and allows you to post and share. Register Here.

The R18 sidecar thread

  • <i class="fa--xf fal fa-check "><svg xmlns="http://www.w3.org/2000/svg" role="img" aria-hidden="true" ><use href="/data/local/icons/light.svg?v=1775602443#check"></use></svg></i> Discussion starter Discussion starter Petrus
  • Start date Start date
P

Petrus

Well-known member
Joined
Jul 18, 2025
Messages
962
Location
Vva. del Rosario - Málaga - España
Visit site
Bike
R18, Nimbus Type C sidecar, Vespas
There seem to be half a dozen of R18 sidecar combis on the forum and at least two work in progress.

Since sidecars are something else, I thought it appropriate to open a separate thread and join the info. As such I will try put some of the links to other threads in here as well.

Point is case of them being something else is the bewildering variety of ways the chairs are mounted to the R18. I mean one specific frame and I have counted a DOZEN of different mountings!!
I have no info at all about how those are set up but the equally bewildering variation of guides about that make me not even wonder about that :ROFLMAO:

Now this thread is not, NOT about whether them's a good idea or not because that is neither here nor there and the bottom line is that they are not a good idea from an engineering point of view. They are an anachronism from the time a wicker basket seat was fitted to the side of a bicycle.
This however totally missed the point as the experience is totally different too in two aspects.
For one it is the asymetric everything and direct steering make it by a large margin most involving vehicle to ride/drive.
Secondly there is a weird social aspect to it: The general public thinks they are endearing, disarming and women in particular think them romantic.

Right; please share (y)
 
First link is to thread about a tool just about all will need to connect the sidecar electrics:

A

Thread 'Canbus installation for trailer plug (and other accessories)'

installing a canbus on the R 18 series is (as it turns out) a simple operation. I used the HEX ezCAN K1600 unit. See the attached installation guide that I and the tow-hitch installer wrote. On my Transcontinental I had a tow hitch made by TEXASSIDECARS. It is a bespoke hitch as no-one has previously manufactured one. I understand that TEXASSIDECARS are intending on producing this hitch commercially. In a nutshell - DO NOT install the canbus to the wiring loom under the seat. It is installed into the DWA (ALARM MODULE) which is located above the battery behind the left side panel. The...
  • Like

Next more generic:

laennecr

Post in thread 'Sidecar Riders and Installers...'

I had a crappy 98 Ural Deco that died. Took the sidecar off and hooked it up to my Classic. Texas Sidecar Company did a stellar job with the connection. As far as voiding the warranty that is not true. The sidecar easily detaches so the dealer can work on warranty issues; only one so far. Using a Hex EZCan for sidecar lights with no warranty issues as well. Hook it up and enjoy life. FullSizeRender.jpeg
  • Like

D

Post in thread 'R 18 TC & Sidecar'

Great question. I've been looking into this as well. There is a 2021 BMW R18 First Edition with Hannigan Heritage Sidecar by me - looks great. Here is a video when it was for sale - shows the mounting points etc

here

The most known ones have been the R18 with the watsonian sidecar.

I have not seen anyone with a R18B or R18TC and a sidecar. I'm not sure if the side bags allow enough distance / space to mount a sidecar.

Have you found out anything?

R2K

Post in thread 'Sidecar mountings'

Forgive me for invading your post without being able to answer your request. I thought you may be interested in my project with what you are pondering. I am having this Watsonian Squire Grand Prix built at Texas sidecar and mounted to my R18FE. I can confirm it will cost around $12K when all is said and done. This includes the dealer mounting of $1500.00. It will also end up taking at least a year to complete. I agree with you that it is a perfect bike for a sidecar with the added benefit of reverse. I have a Harley with a sidecar that does not have a reverse and I get along with...
  • Like

D

Post in thread 'R18 with Sidecar ''

Toyboy said:
One of the first, NOT the first. Looks awesome to boot. Seen it in person. Super shop as are the owners.
Click to expand...
Yeah,Watsonian sidecar made in England.They have been making sidecars for around 100 years.I checked into them.They look kinda like a Steib sidecar that were put on BMWs years ago.A friend of mine has one on a Sportster.After,he saw my rig he really got excited and now wants a bigger bike to purchase a Hannigan with the ECC.
The price on the Watsonian was not bad except for the shipping was gonna bump the price up quite a bit.Next,there is no entry door.Having bought a Hannigan...
  • Deleted member 939
  • Like

M

Post in thread 'Sidecar'

too funny...smart man on both counts though indeed a sidecar on an r18 would be way cool me thinks. I do though wonder if it would make a difference if one had a base R18 vs a B or TC model when it comes to suspension comfort. I had always thought, due to the sidecar rig, that the bike back end sort of becomes a hard tail (aka no really rear suspension else very little due to being bolted to a side car).

If such is the case wonder then if an R18 will give about as much comfort suspension wise as a B or TC when car is attached.

Please feel free to add if I missed one.
 
Last edited:
@R2K an me are the two currently with work in progress.
Quite different R18s, chairs and approaches. Love it; the different facets make the diamond!

One practical example of the different routes to Rome is the upper front mounting:
The very best engineering solution for that mounting just looking at that best mounting is to mount it up high and in the case of the R18 frame means using the two bolts joining the frame.
This however has two other engineering disadvantages:
- the higher the mounting the longer the strut thus the larger the resulting forces.
- because of the way the frame cradle bends, the higher also means further in and in effect the exhaust pipe being more difficult to clear. Bending the strut would make it clear but also weaken the structure.
Hence various solutions.
And that is just one mounting.

Right and then there is the Hannigan lean control. The consequence for the mountings is fundamental: They must in effect all be hinges. Structurally 'solid' hinges. By Jove what a challenge.

Did I write I love it?! :ROFLMAO:
 
And than the sidecar itself.

Although the recommendations state that light bike light chair, heavy bike heavy chair, that again is a half true rule of thumb. The logic is obvious as the centrifugal forces of a heavier bike are greater. The crux though is that the sidecar chassis needs be strong enough. Depending on the centre of gravity of the tractor it can be advantageous to balance a lighter weight chair with ballast as that can be put where it benefits the dynamics best.

Another good example of half true rule of thumb is the track width. Again the recommendation goes light bike, narrow track, heavy bike wide track. Again yes but... A wider track means the chair will lift later but all the forces will have a longer lever length and on the road it means more push and pull effect of the chair.
Also a wider track goes hand in hand with needing more toe in, meaning more tyre scrub.
Sometimes the manufacturer of the sidecar recommends a track with so that it is that then ;) Give or take a few% :ROFLMAO:
 
Here' s the tech specs of mine;

velorextechspec.jpg

It specifies 102.5 cm track width whereas the previous model was 105 cm. Seems a bit narrow so checking up on that.
For reference, the track width of the current IMZ Ural rig is 112 cm. and the old ones were 102. My Dnepr was 105. The ground clearance and c.o.g. of these is higher than than of the R18. It may thus even be correct. Also my chassis is 75 mm lower than the standard 562 chassis to match the R18.

The MZ ETS250 had 110 cm.
My Nimbus comes at a whopping 115 cm. but then is un-sprung and also has rather a lot of lead for such.

@laennecr
I hope you can provide some measurements/specs on your rig as it is an interesting combination of Ural with R18 done by experienced specialists.
 
Last edited:
and for ANYONE with WHICHEVER sidecar rig I suggest downloading and reading;



and next there are three free downloadable documents form Hal Kendall

Downloadable Guides & Articles -- Cycle Sidecar - Affordable Motorcycle Sidecars :: Providing high-quality motorcycle sidecars since 1999 – Cozy Sidecar & Sidecar Parts | Where To Buy Sidecar for Motorcycles | Motorcycle Sidecar Accessories | Univers

www.cyclesidecar.com www.cyclesidecar.com


Most likely cheapest to send the files to your local print shop for double sided printing and have them bind them too.

Enjoy.
 
Last edited:
Sourced lead ingots of 12,5 kg each. Collecting 3 this week. 37.5 kg of ballast placed behind the seat to the outside wall seems enough. Will fit them over a single central bolt through the floor with a winged nut on top.
 
Cool :cool: in hot red. Seriously special looking indeed.

Good illustration of what I pointed out about the upper front mounting. This is a special one from Watsonian and (y) but it needs a bent tube to clear the exhaust. Also just that one mounting would cost me close to 300€ :oops: to get here.
Not sure how what I have in mind will pan out. I will try find photos of two alternatives I have seen.

Notice they did not fit a steering damper. I am quite chuffed I did when the opportunity arose, anticipating a possible sidecar.

I have not told my wife I bought the Velorex. I mentioned my intention some time ago and she said no. So, not using any shared money and that is it.
 
Found them.
It is using the ubiquitous generic frame tube clamp design used by all.

Here is the high fit I would want to try achieve.


FrontUpHoog.jpg


Here is the low version which I do not like.
On a side note; why would one want the crash bars on a rig? :unsure:


FrontUpLaag.jpg


Both these riggings illustrate an aspect of many solutions which I would like to try avoid:
The accelerating and braking forces are by the motorcycle frame. They are longitudinal.
The struts of the mountings are mainly transverse, i.e. at right angles with the frame thus forces.
Hence quite large bending/rotating stress on the connections.

Now I am totally aware that I am OCD about this but the R18 is a heavy dude with a lot of torque with the large forces continuously alternating directions.
 
Speaking of interesting.
On the forum we have an Ural chair rigged up to thhe R18.
Found an Ural with a Velorex boot replacing the original one. Reason being the owner had it lying about and thought it looked better. Bones effects being lighter and a bit sleeker for the air.

UralVelorex.jpg

The different facets....
 
btw is there a simple way to delete the side stand kill switch so I can delete that side stand? Like connect the two wires if there are?

p.s. found it; there are apparently sufficient riders with this gripe for the after market to offer plug ins.

Hmm. Deleting buddy seat, passenger pegs and hangers, sidestand... almost compensating the boot weight :ROFLMAO:
 
Last edited:
The HEX EZcan is at customs. As expected the tax, handling charges + tax on that plus shipping and tax on the shipping do add up; 130€. Bl@@dy Brexit. Could not be helped though because bl@@dy BMW CANbus.
 
with the ingots curing :ROFLMAO: adjusted the valves. Yes in the sidecar thread because the tub side is ever so much easier to do before fitting that. The RH cyl. was pretty much within spec. but set it in mid spec anyway, The LH cyl. all four were a bit too wide.
 
You must log in or register to reply here.
Back
Top