Adventure Supermoto

[Nick V]

I thought the wheel was designed to rotate one way, the arrow mark on your rear wheel will now point to the rear, do you not think from a design/strength point of view that it is unwise to change this?

Not at all.
Plenty of automotive alloy wheels have a leading/trailing spoke arrangement. Most are non-unidirectional. Mounted to cars, these would be 'trailing' when mounted on one side, and 'leading' when mounted to the other side.

A bonus is that the wheel is less likely to develop stress cracks in this arrangement. Mounted on K-series, the spokes are under tension on the move. Mounted on R-series, a K-series wheel will have the spokes under compression.
In any case, there are nine or ten GSs and GSAs running around with K-series rear wheels in Johannesburg alone (two of which I own, and two more of which I've ridden at very high speeds without incident).
You have to remember that aluminium-alloy wheels are over-engineered for an approach of added safety through redundancy. Most current BMW Motorrad alloys are made by Brembo - a 'high-prestige' automotive component supplier. You can imagine the negative publicity and loss of customer faith if word got round that Brembo wheels had started developing cracks - even in 'abnormal' use.

I believe that in this case, the directional arrow cast on the rim is an attempt to make the wheels 'idiot-proof'. For a conventional K-series mounting arrangement, it serves as a warning not to bolt the wheel to the hub from the wrong side. (Before anyone says "FFS... no one would be stupid enough to do that...": I've seen it done more than once on cars.)

 

[vitomoto.gs]

Re. the offset: I've had the opprtunity to compare an R1200RT rear wheel and K1200S rear wheel back-to-back on the same GSA.
Oddly, it's the R-series wheel that has the most offset. The K-series wheel seems to be tracking more-or-less dead straight.

Okay let's open this up one last time to settle on what wheel has the best center alignment on a '04-09 R1200GS

How do you explain the K-wheel being better centered than the R-wheel when...

Double checked everything, the standard 1200gs alloys are a 4.00x17 with a 32 mm offset which appears to run on centre.
The r1200rt rear wheel is a 5.5x17 rim with a 44 mm offset , on the gsa it runs 6mm offset to the nearside (left).
If it is correct that the k1200gt rim a 5.5x17 has a 39mm offset then it will actually be worse , on the gsa it will be running 11mm offset to the nearside.

... Neil did this calculation?


The real question: K or R for best alignment?


Ps: Hi all, this is my first post on the forum, and already would like to thank you guys for your extensive research on this topic! cheers!

 

[Nick V]

The real question: K or R for best alignment?[/I]

I don't know about anyone else who's ever run wide 17" alloys on a K25, but I've never felt any negative handling effects from differences in centre alignment these wheels have.

So, the real question isn't 'K or R for best alignment'. The real question is: Does it matter?

I'll qualify that: At one time, I was running two different K25 GS Adventures. One had a K1200S rear and R1200S front wheel. The other alternated between two different sets: K1200S front and rear, and R1200RT front and rear.
The biggest differences in handling that I noticed came from experimenting with taller profiles on the rear (on 6"-wide wheels, I went from 180/55-17 to 190/55-17). Even then, the difference wasn't massive.

1. Stop worrying about academic differences.
2. Choose a set of wheels and tyres.
3. Get out there, and ride it like you stole it.

 

[vitomoto.gs]

So, the real question isn't 'K or R for best alignment'. The real question is: Does it matter?

Hey thanks for the quick reply!
I read this thread about three times over haha, so i understand what you're saying. I'm just fussing about the aesthetics.

From your experience, which rear wheel looks best centered?
Although you don't experience significant difference in handling, surely one of both must be the more centered one?

 

[Nick V]

I'm just fussing about the aesthetics. From your experience, which rear wheel looks best centered?

IMHO, as far as aesthetics go, a set of R1200S wheels would look best of all.
There's a catch to that - I live in South Africa, and the R1200S was considered Yesterday's Papers by the local 1000cc superbike crowd even before it was launched. (Fools. Fools, the lot of them!) As a result, it never sold well here. K1200Ss and K1300Ss were more popular, and as more and more got crashed, more wheels started finding their way onto the market.
I have never had a rear R1200S wheel.

Although you don't experience significant difference in handling, surely one of both must be the more centered one?

To be honest, I've never paid much attention to that side of things. My #1 concern is how well my equipment works - not how it looks. I use my K25 to wait in lay-byes on the local mountain passes, then chase down passing sports bikes.

 

[vitomoto.gs]

IMHO, as far as aesthetics go, a set of R1200S wheels would look best of all.

Thanks! Although this reply got me kinda confused, since before i read:

But the K-series rear wheels give a great deal less offset - so little, in fact, that you can't see it from the back. By contrast, the offset of R1200S/ST/R/RT wheels on the GS is so obvious that it actually looks a bit scary.

Care to clarify? I'll shut up after, i promise!

 

[Nick V]

Thanks! Although this reply got me kinda confused, since before i read:



Care to clarify? I'll shut up after, i promise!

The offset measurements look scary on paper. And they look even scarier 'in the flesh'.

But while you're riding the bike, you can feel nothing out of the ordinary.
There is no misalignment at the steering head. There is no difference in feel between steering left and right. There are no frightening handling quirks.
After a while, you start feeling a little embarrassed that you thought there was anything to worry about in the first place.

I'm looking forward to seeing your conversion!