Add a GS Torque Arm to your R Bike

Found an R1100GS torque arm through IBMWR for $65. The stock R-R arm is 385mm center-to-center; the GS unit is 365mm.

It's actually a really easy switch to make.

First, obviously, put the bike on the center stand and since you're going to be pushing/pulling hard on rear components, you'd be smart to secure the front wheel to the center stand so you can't rock the bike foward off the c-stand.

I ditched as much weight as possible from the rear end to bias the bike forward - side cases off, seats off, etc.

Since both bolts & nuts are the same on my bike, all I needed was a 16mm socket, a 16mm box-end wrench, and a torque wrench for reinstallation.

Loosened both nuts and removed the rear bolt. Notice the final drive fitting has what looks like a stainless steel insert that semi-floats inside some kind of rubber bushing. The rear end of the torque arm fits OUTSIDE this spot on the final drive; the FRONT of the torque arm has the same steel-and-rubber insert that fits INSIDE the fitting on the transmission. Impossible to get the torque arm installed backwards.

To get the front bolt out, I had to depress the brake pedal and hold it down to get to the bolt. If my footpegs weren't lowered, requiring the brake pedal to be adjusted downward, it would have been a lot easier/faster to get out. It wasn't hard, just slowed me down a tad as I don't have that Third Arm attachment yet. I understand it's a Special BMW Tool(tm) soon to be available.

Swap out the torque arms, being sure to put the stock one down and not pick it right back up, then re-inserted the front bolt and made the nut finger-tight.

To get the rear bolt back through the new torque arm and the fitting on the final drive, I had to push UP on the back of the bike. Luckily the side case mounting bar provided ample acreage for grab & push. Once I got both bolts mostly tight, I checked the torque specs (43 N-m) and used the torque wrench to get them in properly.

I like this kind of abstracty picture, that's all

So that's what I did today instead of ride a nice 250-mile loop out VA 55, across the mountains, and back across US 33.

BTW the red glow in some of the pix is my t-shirt. Kind of cool.

Anyway, a quick test-ride (scofflaw that I am!) to the gas station, up US 1, and back home through the other end of my neighborhood does indeed show increased ride height; my unofficial estimation would be that the 20mm shorter arm gives approx. 1.5 to 2 additional inches of ride height at the seat level. I could tell in my knees *immediately*.

I couldn't really blaze it through my residential area, but even at 25-30 mph in 2nd gear turning in felt tighter in both directions.

Before:

It's not exactly the same angle and lighting but it's kind of close...

I didn't give half a thought to what I did with the original torque arm - I just tossed it in the back of my truck where I keep my tools.

I had to work on my truck yesterday...and found a new use for the old torque arm.

(the hydraulics on my hood have never worked properly...now I can work under the hood without holding it up with one hand!)

What does this do for you?

Turn-ins on the bike feel a lot tighter, like I don't need as much linear/forward movement to make the same turn as I did before...not sure if that's what is actually going on, that's just what it feels like. I like it a lot. The 850 is a relatively low-powered bike and I'm a really big chunk of humanity, so anything that firms up the ride and tightens the line a bit is a plus in my book. I've compared it to dropping the forks in the triple clamp on a "normal" bike, as it has basically the same effect.

I think the idea of an adjustable torque arm is pretty trick... but honestly how often would you really adjust it? How often do you adjust your shocks to mediate weight changes (passenger, luggage, etc.)? Or even your tire pressure? I'd say if you're a tweaker, always adjusting those things to match your riding condition, then an adjustable torque arm is probably a good idea. Otherwise it seems like overkill.