Lowering/Raising the forks in the triple trees

[markjenn]

I did this today and thought I'd make some observations for those who are considering lowering (or raising) the forks from the stock setting. I wanted to lower my forks so that their tops were near the top of the triple rather than three or four marks down as they are stock. This is to slow the steering a bit, raise the front end of the bike (for more comfort), and basically make the bike more suitable for my primary usage: sport-touring. (As an aside, I really liked the handling of the bike afterwards.)

As these things tend to go, what I thought was going to be a 15-minute job took a couple hours.

Step 1: Raising the front end of the bike

Obviously you want to raise the bike by the chassis so the forks are unloaded. If you have an exposed garage rafter or some other hard point overhead, you can use rachet straps to lift the bike, being careful with attachment points. Or if you have one of the Bursig stands, you're good to go as this stand lifts both ends of the bike by the chassis. I had neither rafters nor a Bursig, so I used my pit-bull front end stand that lifts by a pin that goes into the bottom of the steering head. I had to order a new pin from pit-bull. Either a #2 or #2T will work, although pit-bull says the #2T provides a little extra clearance.

To use a steering head stand, you'll need to remove a screw holding the brake-line junction assembly so you can move it aside - BMW in their wisdow placed this assembly right at a spot that blocks access to the bottom of the steering head where the pin goes.

Also, be aware that the forks will be very hard to turn after the lift and the stand will limit the degree of turning. For this reason you may want to loosen the difficult-to-access lower fork clamp bolts prior to the lift while you can turn the steering easily from side-to-side.

Step 2: Loosening the fork clamping bolts

There are 3 bolts that clamp the top and bottom triple to each fork leg - two on the bottom triple and one on the top. All are the same Torx size. I had quite a bit of trouble getting good access to the lower bolts on the bottom, especially on the right side where the steering damper interferes. They face directly forward and there isn't much room for a rachet with the fairing, headlight connectors, steering damper, etc. All I have is Torx sockets - perhaps if you have the right kind of Torx wrench it is possible to loosen/tighten those lower bolts from the top, or you might be able to remove the small plastic splash shield and get to them from the bottom. I punted and removed the side panels which come off fairly easily. With the side panels off, you can turn the forks to one side or the other and have good access, including the ability to use a torque wrench when you tighten things up.

Even if you don't need to remove the side panels, you may end up doing it anyway as anything you drop will have a tendency to disappear into the bowels of the fairing as happened to me.

Step 4: Loosen the handlebar pinch bolts

Straightfoward. You can do this step after the next if you're moving the forks down.

Step 3: Moving the forks

I wanted to lower the forks to raise the front of the bike, so I just left the top clamp bolts slightly snug and then tapped the forks down with a hammer and a block of wood. I'm sure tapping the forks up is equally simple. Afterwards, I tapped the handlebars up, keeping the tabs in the slots. All this is easy.

Step 4: Re-assembly

Obviously, just the reverse of what you did getting here. As you're torqueing the bottom clamp bolts, make sure you do them from side-to-side a few times - as you successively tighten each one of the pair, the other will need further tightening as they approach their final/equal torque.

Happy wrenching.

- Mark

[Joker]

Thanks for the info...I've wondered how many people have tried this. I would assume (with my limited experience) that by lowering the fork tubes as you did the result would be an increase in wheelbase which would improve stability (for sport tour riding like you mentioned) at a cost of agility. Any thoughts from your experience after the change? I was considering going the other direction. I ride 3/4 canyons 1/4 track with almost no tour type miles and I would like to have a quicker flicker.

[markjenn]

Originally Posted by Joker

I would assume (with my limited experience) that by lowering the fork tubes as you did the result would be an increase in wheelbase which would improve stability (for sport tour riding like you mentioned) at a cost of agility. Any thoughts from your experience after the change? I was considering going the other direction. I ride 3/4 canyons 1/4 track with almost no tour type miles and I would like to have a quicker flicker.

Yes, lowering the forks in the triple increases wheelbase and adds trail which helps stability and makes the motorcycle steer more slowly. Raising does the opposite. You can also affect things by raising or lowering the rear of the bike - here the affect is reversed - higher is less stable. The interaction between the two can get pretty complex and is a big part of the elusive "proper setup" that racers look for at the track.

- Mark

[redleader666]

What was the change in mm from before? Now how many from the top of the triple? How noticeable was change in steering? Does it hold a line better or still feel like it wants to fall in to the corner? Thanks.

[1000RR]

If you get a chance... try the following and let me know what you think... flip the rear eccentric from stock and drop the triple to 8mm below the top of the forks... Turns in nice and still remains stable under throttle, drive out is good... of course this is assuming you have the suspension set properly (sag/spring rate/etc.).

[kevin_stevens]

In retrospect, do you think your way worked best, or if you did it again would you pull the front wheel and move one fork leg at a time?

KeS

[markjenn]

Originally Posted by kevin_stevens

In retrospect, do you think your way worked best, or if you did it again would you pull the front wheel and move one fork leg at a time?

If this is directed towards me, I don't think there is any problem doing both fork legs at the same time or doing them individually as long as you end up even at the end. Obviously if the wheel is still attached, then the axle is going to cause the two legs to want to move more in unison, but the suspension gives the whole thing some slop. Unless I had the wheel off for some other reason, I wouldn't remove it.

- Mark

[markjenn]

Originally Posted by redleader666

What was the change in mm from before? Now how many from the top of the triple? How noticeable was change in steering? Does it hold a line better or still feel like it wants to fall in to the corner?

I didn't measure where I started, but it was the stock setting, which I think is about 3-4 rings showing above the triple. I'm now running the forks nearly flush at the triple.

The change in handling was about what I expected - not dramatic but noticeable. The bike is very steady in a straight line and seems to track more straight ahead after a bump - I can ride hands off the bars indefinitely with little effort. It does seem to take slightly more bar pressure to initiate the turn, and seems to track through corners with slightly less tendency to deviate from the chosen line.

Standard tradeoffs - not optimal for the track or extremely tight roads where you're slicing/dicing, but it still handles fairly nimbly. Seems more stable.

I should point out that I'm not a fan of bikes that tend to fall into corners at the slightest bar pressure and don't like highly triangulated front tires. I like bikes that are smooth and steady, take deliberate bar pressure to establish a lean angle and are completely neutral in the corner, not requiring any bar pressure to arrest the lean. I dislike handling that requires counter-steering after turn in to stop the lean from increasing.

I strongly suggest to anyone who is serious about their bike and its handling to take the side panels off and start fiddling with this stuff - make a change, go ride, make a change, go ride, etc. This is how you figure out what works for you riding style.

YMMV.

- Mark

[redleader666]

Originally Posted by markjenn

I didn't measure where I started, but it was the stock setting, which I think is about 3-4 rings showing above the triple. I'm now running the forks nearly flush at the triple.

The change in handling was about what I expected - not dramatic but noticeable. The bike is very steady in a straight line and seems to track more straight ahead after a bump - I can ride hands off the bars indefinitely with little effort. It does seem to take slightly more bar pressure to initiate the turn, and seems to track through corners with slightly less tendency to deviate from the chosen line.

Standard tradeoffs - not optimal for the track or extremely tight roads where you're slicing/dicing, but it still handles fairly nimbly. Seems more stable.

I should point out that I'm not a fan of bikes that tend to fall into corners at the slightest bar pressure and don't like highly triangulated front tires. I like bikes that are smooth and steady, take deliberate bar pressure to establish a lean angle and are completely neutral in the corner, not requiring any bar pressure to arrest the lean. I dislike handling that requires counter-steering after turn in to stop the lean from increasing.

I strongly suggest to anyone who is serious about their bike and its handling to take the side panels off and start fiddling with this stuff - make a change, go ride, make a change, go ride, etc. This is how you figure out what works for you riding style.

YMMV.

- Mark

Thanks for the response!

[chopt]

If you get a chance... try the following and let me know what you think... flip the rear eccentric from stock and drop the triple to 8mm below the top of the forks... Turns in nice and still remains stable under throttle, drive out is good... of course this is assuming you have the suspension set properly (sag/spring rate/etc.).

I suggest everyone try this set-up.