chris846 wrote:Seeing as this thread is (still) about the possibilities of fitting wider rear wheels to a K, I'll add this because some future reader might find it useful.

The 5-spoke (best looking wheels ever) rims fitted to the K1200 are a common choice. They can be hard to get hold of, compared to the very similar looking wheels fitted to boxers from the same era. Most times though, people find they can't use boxer wheels for two reasons: boxer wheels have disc mounting posts cast onto the spokes (Ks don't - the disc is sandwiched between the wheel and the hub), and boxer wheels have too much left offset (sometimes described as 'A' and 'B' wheels - is this to make up the space for the 'missing' disc?)

Well, the problematic extra offset on a boxer wheel can itself be 'offset' by leaving out the k series disc, and using a boxer disc mounted on the wheel. I did this with a 5" boxer rim (there are 5.5" options out there too) and, with a bit of adjustment to the swingarm pivots, it was possible to get the left offset down to just 3mm.

This itself isn't without a bit of grief; the boxer disc has a smaller OD, but a boxer rear caliper is correct for this, and (in typical BMW style) fits straight on the caliper mounts on the bevel drive (K & boxer bevels are very similar). I had to shift the caliper and disc over to the left (spacers on the caliper, machined a bit off the disc mounting posts) but this was to clear a wider, non-standard shock, dunno if this would be necessary with a standard shock.

Yes Chris timely advice / warning. I went down that route as well when I was investigating all the options 10 years ago !  For some reason [?] the Oilhead 5 spoke Wobblies were cheaper than the Kay wheels. Maybe as much as 25%. There was no research already done  back in the day that I could refer to - so platforms such as this are invaluable to peeps today who might not want to be in the "let's all be different together" club.

I think the answer to this debate [?] is that those who have obviously tried out this format and come to the conclusion that in their view handling is compromised [ Ben Kingham still there ? ]will not want to repeat their experience and those of us who like to tinker and experiment - will.

Did I ever mention fitting the Wire spoked GS wheels to my Kay ............ probably best not to go there. 

"Did I ever mention fitting the Wire spoked GS wheels to my Kay ............ probably best not to go there.  "

Go there please!  Or start it in a new post if it isn't relevant to this thread.  This will be part of a K project which just made it past the approval stage with my Department of Finance.

Woodie wrote:"Did I ever mention fitting the Wire spoked GS wheels to my Kay ............ probably best not to go there.  "

Go there please!  Or start it in a new post if it isn't relevant to this thread.  This will be part of a K project which just made it past the approval stage with my Department of Finance.

Woodie,

think I've ruffled enough feathers on this thread ......... I'll see where else it could be aired [ wire wheels ].

My BIGGEST problem is that I AM the original computer dummy. I'll have to wait for a passing 6 year old to school me on posting pix. BTW - have ANY of my pix shown up ? I followed the "nick it off another site" advice - some from the BM Riders forum and others from the Do The Ton [ DTT ] forum, where I am a regular poster.

Woodie! Take a look at these russian guys. They explain it really well, just turn on the subtitles translation, they also have some useful info on the channel as well. Good luck!

https://www.youtube.com/watch?v=Ua2OaaCFhkk

Thank Artyomka, greatly appreciated!  He makes it look so easy.    My own version of that will likely be full of cuss words and scraped knuckles.

I'm successfully using a 5X17 K1200RS rear wheel on my K12-engined Big Block (with no shim). It has plenty of clearance with the prescribed 170/60ZR17 tyre fitted (A Pirelli), and I could almost get away with a 180/55ZR17. There is a practically imperceptible amount of offset using a Paralever swingarm on a '93 K11 frame. The bike does not 'need' the slightly wider rubber for anything better in the handling department. It'd only be about the look.

I am intrigued by the various uses of GS tubeless wheels on K bikes which I've read about, however.

Ok I'm brand new to the forum, and diving right into modding my '86 K100.  I've got a line on a "K1200rs GT 17x5" rear wheel..  Almost made the mistake of picking up a much cheaper R1150 wheel before reading up on all the offset and brake mounting differences..  So my newby question is how close of a fit is this wheel to a standard k100 swingarm?  still learning about these bikes so please be patient with me and my ignorance!  Looks to me like the other examples I'm seeing here are with a later style rear drive? Are there some limitations to the older drives such as on my bike? I'm not afraid of some modifying..  There is a well used set of Tig welders, milling machine and lathe in my shop..  just dying for a more fun use than building milk processing equipment.  Looking forward to getting to know all of you on here!

K1200RS had as standard a 5x17 rear wheel for 170/60ZR17 tyres, and, later in the model run, as an option a 5.5x17. The K1200GT only ever came with a 5.5x17 rear wheel for 180/55ZR17 tyres. The 5" version will fit on a Monolever swingarm but there's barely enough room to slide a red pubic hair through there due to reinforcement casting on the inside centre.  But it can be done. The 5" version fits a Paralever, no dramas (see Big Block).

The wheel will foul on the monolever swingarm, but you can add left offset with additional spacers (but check the bolt length). How much left offset are you prepared to tolerate? - it'll be in the order of 5-10mm, which won't really be noticeable in riding, but the visual effect of the measured offset is doubled. You might also need too take your hacksaw/welder to the centrestand, but it sounds like you'll enjoy that  .

IMHO the way forward is a paralever back end. They look better, they are better, and they out-perform a monolever by a factor of about a billion. Downside is they add wheelbase (about 35mm), it can be a costly conversion, they add weight, and they add complexity which isn't really needed for steady touring use.

Found it again!
This is the bible for wheel swapping:

http://www.largiader.com/parts/wheels.html

Ok that wheel swap guide is super helpful, thank you!

The new wheel has a 5"x 17" in the casting, so I think I'm on the right track there..  I think if I can stick with the monolever rear at least for now I will.  This will suck up enough disposable cash without me looking for ways to spend more!  There is always a stage II on this kind of build, no?   I came across a picture somewhere (lots of rabbit holes on the internet!) of a monolever that had been clearanced slightly, removing the casting seam.. Is there any space internally to extend this clearance?  or is the driveshaft close fitting?  Also saw a reference to offsetting the swingarm at the other end to compensate?  This build will hopefully be about KISS, but I'm more about fabricating fixes than buying them.

Not sure about taking any metal off the monolever - my guess is that rib is there for a reason. Yes you can put the offside 'fixed' swingarm pivot in a lathe and move the swingarm rightwards, but this is only very slight and gains no more than a few thou.

An alternative wheel could be the 4.5"x18" 160 section tyre three spoker fitted to the K1100RS - slightly narrower than a 5", easier to clean than a snowflake 4-spoke, but not as lovely to look at as the 5-spoker you're thinking of.

@suzi Q. The link to the bible of the wheels (and the whole web) is spectacular. 

 I will tell you what I am working on.  
On a K100 8v I am installing the 5 spoke wheels of an R1150r.  I didn't know the difference between boxer and K1200 tires. 

 On this rim I have milled 10 mm on the seat.  He's still very stiff.

  I have mounted the disc for that rim by removing the original from the K100. 

 I have not changed the cap of the final group like in the video.  This makes the transformation more expensive.  And in Spain they are not easy to locate. 

 Just milling brake caliper  holder a bit (on the brake caliper) has been enough.

  Comprobé con un láser la alineación del conjunto con el chasis y salió bien. Pero al hacer una doble verificación con algunos rieles calibrados llevándolos de la rueda trasera a la delantera, todavía encontré que había 2 mm de retraso. 

 Puede que esto no importe como dices. Que bmw diga un retraso de 10 mm como correcto me parece más una excusa. 

 Tampoco cuestiono lo que dices de los pilotos que han corrido con ruedas de retraso. Pero en el capítulo dedicado a las ruedas del libro "chasis" de Jhon Robinson se le da la máxima importancia (y lógicamente estoy de acuerdo). 

 Como es una moto que voy a preparar por completo y tengo que desmontar todo el motor para llevarlo a la pintura en polvo, lo voy a aprovechar y voy a fresar esos dos mm en el cárter. Moviendo todo el motor 2 mm hacia la derecha. 

 ¿Tendría que hacerlo? No. ¿Lo voy a hacer? Si. 

 Es más una cuestión de hacerlo perfecto. Delante he montado una impresionante horquilla de 58 mm de Benelli Tornado. 

 La última Boldor que hice montando 120 y 180 perfectamente alineados, la moto se sentía como una Honda cb500.  

Además de montar en un monstruo de 750 radios, llantas Paul Smart. 

 Y también me he dado cuenta. Intento poner fotos. Mantengo este hilo muy atento. 

Gracias a todos por tanta buena información.

I have a spare 5"x17 1200RS rear wheel if anyone want to give me and offer. Good condition.

warmshed wrote:I have a spare 5"x17 1200RS rear wheel if anyone want to give me and offer. Good condition.

The best place for this is in Buy & Sell on the forum

"I've got a 5.5" x 17 wheel in my K with a 180 section tyre using a Mono rear end."
i would be very interested in talking to anyone who has done this conversion as all i'm getting at the moment is conflicting responses, some say its impossible others say it can be done and have done it!
i've been informed that you can fit a 5" wheel to a monolever 4 stud. others talk of machining 20mm of the hub? i do have people that could do this sort of thing but before i chuck flipping great wadges of cash at it i would like opinions on people who have already achieved this
alaways gratefull for any help or advice
cheers guys
ming

You can do anything.
But does it worth it?
Big wheels are just a fashion no road bike needs.
Even on race track, during the classic endurance races I was involved, we could see old BMWs and Moto Guzzis with narrow tyres much more rapid than Hondas or Kawasakis GG with big tyres...
The wider it is , the more angle you need to corner the same curve at the same speed.

But if you absolutely want to alter the perfect handling and balance of the genuine K100, then take a ruler and use it.

I have various wheels for my K1100 and tried both the wider and narrower ones. 

It is very much the case for me that the wide ones are harder work, narrower ones are so much nicer to ride, more precise.

92KK 84WW Olaf wrote:I have various wheels for my K1100 and tried both the wider and narrower ones. 

It is very much the case for me that the wide ones are harder work, narrower ones are so much nicer to ride, more precise.

Ride performance is not the goal of cafe builders.  Why do you think you never see one actually being used to ride someplace?

Actually, road performance is also the goal of the cafe racers I build.
And use...

El objetivo de lasncaferacer en sus inicios fue precisamente para lograr motos más rápidas.
Puede que algunos no le den importancia a construir una moto funcional.
En mi caso el orden siempre es: Segura, fiable y por última bonita

Sorry ..

The objective of the caferacer in its beginnings was precisely to achieve faster motorcycles.
Some may not give importance to building a functional motorcycle.
In my case the order is always: Safe, reliable and lastly beautiful

ming above you have a message from me.

It is impossible to mount a 5" rim with 170 centered on a k 100 monolever.

You will have a minimum offset of 4mm with respect to the front.

There are many things that you have to change to get those 4mm. More centered is impossible.

You could only move the motor 4 mms to achieve it.

This was an assembly that I did for myself and that I did not finish. In fact I have passed all the modification to a k from a client.


And to get those 4 mms with enough clearance between tire and monolever you have to mill it and remove the nerve, and more.

once the nerve is removed and even the cardan shaft you have 5 mm.

But of course. you don't want to remove them all.


The problem with using the brake caliper on the R1150R is that before the brake pads wear out, the caliper will touch the shock.

Anyway, that's my experience.