Adventure Supermoto

[Neil W]

I have a real hankering to fit my Adventure with a set of 17 inch rims , I was planning to go down the proven route of r1200rt rims BUT having looked at a r1200r classic with spoked wheels I think it might be the way to go.
Question is has it been done before and has anyone got any links to photographs ?
Also some posts say the rear wheel needs machined to sort out alignment problems, does that mean that the r/rt/st models have a different bevel arrangement
I will be using a 120/70 front tyre and a 170/60 profile rear tyre

 

[DING-DONG]

If you use rt wheels you won't have to file the front calipers as they catch about 1mm on the edge of the caliper if you use r1200s or r1200r wheels, I've done several now and the rear wheel don't need machining at all, I've ran 6" on the rear with a 190 tyre .

My last one.

 

[Neil W]

That's the look I'm after , after the hols I'll be looking around for a set of wheels

 

[red line]

this is not my bike, but mine is 99% like this.... you also need to grind down the right foot of the center stand about 5mm and use a 5mm spacer to move the end can out.
the rear wheel is about 5mm out of alignment, but you hardly notice it. Not sure if this can be machined to correct as it seems the right side will touch the swing arm if you do machine it? maybe someone has?

 

[Bendy toy]

Ive got a pair of GS wheels on my GSA. They wont give the quicker handling of a 17" front wheel and they are no lighter than the wire spokes, but they are easy to clean and look great in a shiny black finish and ground clearance is unaffected.

Even small things like removing the centre stand and coating the crash bars in black make quite a difference

 

[Nutty]

this is not my bike, but mine is 99% like this.... you also need to grind down the right foot of the center stand about 5mm and use a 5mm spacer to move the end can out.
the rear wheel is about 5mm out of alignment, but you hardly notice it. Not sure if this can be machined to correct as it seems the right side will touch the swing arm if you do machine it? maybe someone has?

That looks nice. Black out the panels and rear carrier, and that would look fantastic.

 

[Nick V]

I was planning to go down the proven route of r1200rt rims BUT having looked at a r1200r classic with spoked wheels I think it might be the way to go.

I've been thinking about this... something that would save the hassle of finding a set of R1200S alloys would be to use the standard R1200GS front and rear hubs, and lace on a set of suitable-width 17" Excel rims - or similar.

Also some posts say the rear wheel needs machined to sort out alignment problems, does that mean that the r/rt/st models have a different bevel arrangement.

This is definitely the case if you're using a K1200S rear wheel. However, no one has yet been able to tell me by how much the rear needs machining...

If you're using an R-series rear wheel, this shouldn't be the case; IIRC, they all use the same gearbox casing (or at least very minor variations thereof), so the rear wheel should remain in alignment.

I will be using a 120/70 front tyre and a 170/60 profile rear tyre

With a 5.5in rim, I would stick to a 180/55. If you're using a 6in rim, you can quite happily use up to a 190/50 or 190/55 if you want to - I've had no clearance issues on my GSA, using a 6in K1200S rear wheel with 190/55 tyre.
And: at no point has the centre stand touched the wheel or tyre.

 

[Neil W]

Well just thrashed a 2013 caponord, 2003 falco and a 2013 1250 bandit (all solo) whilst two up on the gsa over the Grossglockner, what could it do with the 17" rims and sticky tyres

 

[Wreford Miles]

Well just thrashed a 2013 caponord, 2003 falco and a 2013 1250 bandit (all solo) whilst two up on the gsa over the Grossglockner, what could it do with the 17" rims and sticky tyres

oh my that tales made me go all faint... im not use to being in the pressense of such tallent

 

[Neil W]

Well got the 17 inch rims fitted (ex R1200RT) and it seems canny, but what is the consensus amongst those that have tried this regarding the best front mudguard to use.
I cannot justify the expense of a £200 aftermarket one if I decide to change it back.Will the r1200s/r ones fit

 

[Nick V]

Well got the 17 inch rims fitted (ex R1200RT) and it seems canny, but what is the consensus amongst those that have tried this regarding the best front mudguard to use.
I cannot justify the expense of a £200 aftermarket one if I decide to change it back.Will the r1200s/r ones fit

They may fit - but I don't think there are 'bolt-on' mounting points for these mudguards on the GS lower fork stanchions. And IMHO, they are as ugly as sin.

A fellow I'm liaising with here who's also done the conversion is using a mudguard from an F800ST, held in place with thin stainless steel straps which loop around the lower stanchions to provide a mounting point. 5mm bolts, washers and nuts complete the picture.

It looks surprisingly good.

If you decide to go this route, you could pick up the same mudguard from an F800S or F800R.

 

[Nick V]

I completed my conversion this weekend.

K1200S rear wheel, R1200S front. No front mudguard mounted as yet (the standard guard looks really weird with a 17" front), but I've sourced a very lightweight one which originates (I THINK) from a Cagiva Mito 125. Looks good... we'll see!

A couple of helpful points for anyone thinking of undertaking this conversion:

1. The GS/GSA front wheel axle spacer will not seat properly inside the left-hand grease seal of a BMW 17" front alloy wheel. You will need to use the wheel axle spacer from the bike you pirated the wheels from.
2. If sticking with the standard 305mm front brake discs, you will need to shave the inside lower edges of both front brake calipers by 0.5 to 1mm. If you don't, the wheel's brake-disc mounting bosses will impact the calipers when the wheel turns.
3. After a little experimentation, I found that the following configuration gives the quickest steering with the most stability (85 Kg rider, 'one-up'):

• 190/55-17 rear tyre (Metzeler Racetec K2) set to 2.7 Bar (cold).
• 120/70-17 front tyre (Pirelli Diablo Supercorsa Pro) set to 2.3 Bar (cold).
• ESA settings: preload at setting 3 of 5 (i.e. two helmets). Damping at 'Comfort'.

She is a friggin' hooligan!!!!


Now I know what Jeremy Clarkson was on about when he tested the Bentley Continental Supersport, and called it 'an elephant with the reflexes of a water boatman'...

 

[Bendy toy]

Mine has black powder coated GS wheels so looks similar to this but handles exactly the same as it did with wire spoked wheels. Presumably the sportier looking wheels in the pic are also are lighter. The standard GS wheels and wire GSA wheels are a straight swap and weigh almost exactly the same. The backs are within 0.5Kg. The front alloy is 1Kg heavier than the wire.

 

[Nick V]

Mine has black powder coated GS wheels so looks similar to this but handles exactly the same as it did with wire spoked wheels. Presumably the sportier looking wheels in the pic are also are lighter.

I have a strong suspicion the front wheel would be substantially lighter (two inches off the wheel diameter means that much less metal and 'flywheel effect'). But the rear wheel above, being an inch and a half wider than the GS alloy, would be that much heavier...
S'pose the only way to tell would be to break out the scales.

The standard GS wheels and wire GSA wheels are a straight swap and weigh almost exactly the same. The backs are within 0.5Kg. The front alloy is 1Kg heavier than the wire.

I understand that on UK and European GSs, the 'standard' fitment has always been alloy wheels.
Here in SA, it's always been the other way round: standard fitment is wire wheels - unless the customer specifies alloy wheels.
I almost never see the 'generation 1' ('04 to '08) GS alloys here - they are good looking wheels indeed. I sometimes see 'generation 2' ('09 to '13) GS alloys.

Here, very few people outside of motor racing circles know what a Supermoto is, and to the best of my current knowledge, only one other person has done a Supermoto conversion on a GSA...

 

[Neil W]

I've now run my gsa on spokes, r1200gs alloys and r1200rt alloys wheels and then tried them back to back over the same route on the same day in similar weather. The bike is fitted with full maxton suspension.


Spoked wheels with matched Dunlop TR91 tyres the bike feels fine and handles well enough, when pushing on there can be a little bit of instability at the rear (may be due to tyres)

Standard r1200gs alloys fitted with matched Michelin Pilot Road tyres, the bike feels the same as standard but less instability when pushing on in bends. Again could be down to tyres but it just feels better.

R1200 RT wheels fitted with new Bridgestone BT21r tyres 120/70zr 17 and 170/60 zr 17 , the bike loses no inline stability at higher speed , at walking pace the steering feels heavier and not quite as sharp (bit like a slightly flat front tyre). In bends the bike flows better and is more stable and controlled dropping into corners.
At higher cornering speeds there is no instability and the bike feels more planted.Being a GSA there are no ground clearance problems

The main advantage is a lower seat height.

I took advice from here and picked up a secondhand F800st front mudguard, it fits straight on using four 48mm stainless P Clips and looks standard.

 

[Bobbin-Man]

In bends the bike flows better and is more stable and controlled dropping into corners

Any idea how much of this is the smaller wheel, and how much is caused by the fact that the steering head angle will have been increased because the front end has dropped by around 1"? ie. trail will have been reduced.

 

[Nick V]

R1200 RT wheels fitted with new Bridgestone BT21r tyres 120/70zr 17 and 170/60 zr 17 , the bike loses no inline stability at higher speed , at walking pace the steering feels heavier and not quite as sharp (bit like a slightly flat front tyre). In bends the bike flows better and is more stable and controlled dropping into corners.
At higher cornering speeds there is no instability and the bike feels more planted.Being a GSA there are no ground clearance problems

The main handling 'quirk' I've noticed on mine so far feels worst on the very twisty, very low-speed, bumpy back roads in the hills near my house.
When below about 35 to 40 Km/h, the steering feels a bit weird - almost as if the handlebars are now set too far forward in relation to the headstock.
You're right - in a way, it feels like a slightly flat front tyre. The bike seems to turn 'with a mind of it's own' when you've committed.
It feels like IT is choosing the degree of steer and angle of lean - not you.

It could be worse on my bike, as my choice of tyres has been very racy indeed. I'm currently using a 190/55-17 Metzeler Racetec K2 on the rear; this has a very steep profile indeed, and could be contributing to the low-speed instability. (However, with the same tyre fitted at the rear, the bike did not do this with a 19" alloy and 110/80-19 Bridgestone Battlewing.)
It would be very interesting to see what gain in stability, if any, would be made with no change in tyre dimensions, but a switch to Michelin Pilot Road 2s or Pilot Road 3s.

But at normal roadway speeds, this disappears. Slicing 'n dicing in between traffic is easier - very fast changes of direction now feel like the bike has more composure and precision. It feels like it's saying to you: "What are you swinging the 'bars so hard for? You only needed 60% of that effort".
I'd bet that a lot of this is down to the reduced inertia of the 17" front.
Very high-speed leaning turns still need some work, though.

Neil, what tyre pressures are you running? And under what load conditions?
Also, what year-model is your bike?

I took advice from here and picked up a secondhand F800st front mudguard, it fits straight on using four 48mm stainless P Clips and looks standard.

That would have been me.
P-clips are rather difficult to get hold of here, though...

 

[Nick V]

So now, I have two GSA supermotos in my garage... I've converted the Camhead as well.

For this bike, I used a set of R1200RT wheels in original silver paint.
For being something which, overall, is substantially the same as my '09 Hexhead 'Moto, the two bikes feel very different indeed.

Some observations I can share at this point...

1. My earlier statement that the GSA front-wheel axle spacer won't fit a 17" alloy was wrong. It seems that at some stage, someone fitted a non-standard grease seal to the left-hand side of the front wheel I used on the Hexhead.
2. I also found out, quite by chance, that the lower A-arm fitted to the Hexhead is also from an R1200S (it's threaded for fitment of a steering damper). Looking at the two bikes side-by-side, one can see that the steering-head angle is steeper on the Camhead, which has it's original A-arm.
3. My tyre choice for the Camhead was much less racy. I'm using a 120/70-17 Pilot Road 3 on the front and a part-worn 190/50-17 Pilot Road at the rear. Cold pressures are 2.5 Bar front, 2.9 Bar rear. This bike feels a lot more stable at low speed than the Hexhead. When the time comes to replace the rear, I'm going for a 180/55-17 Pilot Road 3. With a brand-new rear, I anticipate even greater things from the handling. (I am now also more-or-less completely convinced that a 190/55-17 Metzeler Racetec is not an ideal rear tyre for this conversion - the profile is simply too steep. I have very little choice on the Hexhead, though, as with the non-standard gearing and a 180/55-17 fitted, the ASC malfunctions.)
4. I also found my personal best solution re. the front mudguard. I simply cut down the original mudguard, made sure the finish of the edges was 100%, and spaced it down towards the front tyre by about 40mm using appropriate spacers and longer 5mm screws. I plan on doing the same with the Hexhead.
5. Don't think you'll be able to do this conversion and keep the standard exhaust silencer... it's simply too wide. Save a lot of grief: ditch the standard exhaust and go for the slimmest aftermarket silencer you fancy.
6. With R1200R/RT/ST wheels, you don't need to 'shave' the inside edges of the front brake calipers as with as an R1200S front wheel.
7. A tip for anyone thinking of using R1200S wheels: know that not all rears are 6" wide - the 'default' width is actually 5.5". The 6" wheel was a factory-mounted accessory.

I really can't understand why more of the faster riders don't do this conversion; it's actually very straightforward.

 

[Wilsdorf]

I have a R1200S, along with my GS - what does the shaving mod look like? Also, what mods would I have to carry out to put the rear on - it is a full fat 6 inch rim.

It would be fun to swap the wheel around occasionally to enjoy the sticker rubber on 17's - plus, as I have both bikes it's probably cheaper to mod the brakes etc. than buy a spare set of wheel and tyres.

Do I need to alter the side stand and centre stand? As I would not be carrying a permanent alteration - I carry a passenger on the GS for around 50% of the time - but guess with 17's on it I'd be riding faster solo.

 

[Nick V]

I have a R1200S, along with my GS - what does the shaving mod look like?

Unfortunately, I can't post pics. But to give the best picture I can: think from the perspective of looking at the bike head-on.
If you face the front brake calipers from this position, and imagine the ASCII drawing below as the view you would see of the front end of the left-hand caliper (i.e. same side of the wheel as the ABS wheel-speed measuring ring)...

..................-------
.................| _ |
.................| | | |
..............X -- --

(Disregard the dots - they are only there because I can't space the ASCII characters properly without them.)

...then the 'X' is the point at which you will need to file or sandpaper off about 1mm-worth of metal from the caliper (at a 45-degree angle).
You will also need to do this to the right-hand caliper - again, at the points closest to the wheel (i.e. as a mirror-image of the drawing above).
This is done so the calipers will not contact the brake-disc mounting points of the R1200S front wheel.

Also, what mods would I have to carry out to put the rear on - it is a full fat 6 inch rim.

If you still have the standard exhaust, you will need to ditch it - it will not fit. Go for the narrowest exhaust silencer you fancy.
My '09 runs a 6" K1200S rear rim with a 190/55-17 tyre - with the Tornado exhausts I run on both bikes, I haven't yet had any clearance issues.

You will definitely need to cut the inside of the left-hand centre stand 'foot' by at least 5mm; maybe more. The best way to find out is to fit the wheel, then put the bike on the side stand with the centre stand up. Have a close look at the stand foot clearance on either side of the rear tyre sidewall to get an idea.

It would be fun to swap the wheel around occasionally to enjoy the sticker rubber on 17's - plus, as I have both bikes it's probably cheaper to mod the brakes etc. than buy a spare set of wheel and tyres.

It will... but bear in mind that the GS/GSA use 305mm front brake discs.
Unless you want to fool around with machining adaptor plates for the 320mm brake discs that come on the R1200S, you will also need to transfer the GS discs to the S front wheel...

Do I need to alter the side stand and centre stand?

Centre stand... see above.
Sidestand... probably not, but then I don't know what profile your rear tyre is, what your suspension settings are etc.
I haven't had an issue with either of my bikes. If you find that yours is now sitting too far upright on the stand, you may want to try giving it SLIGHTLY more of a 'bend'.