Lean Steer Adjustment

From SegwaySocial

by glen_d on segwaychat

Often owners of second generation Segways complain that that the leansteer frame flops around or is not centered. When this happens often the two brass wedge clamps are not aligned with the aluminum hub when you tighten the bolt. You can tighten the bolt, but moving causes the brass to shift and the bolt loosens.

Here's how you can resolve your problem. Go to most any auto parts store and purchase some anti-seize compound. Loctite is a good brand, and most any product they make will work fine. You should be able to find a small quantity for less than $10. Here's an example from Loctite: http://gsgindustrial.com/detail.aspx?ID=499

You're going to use the anti-seize to resolve a problem with the bolt and the brass wedge clamps. The steel bolt bolt head and threads gall against the brass wedge clamps as you tighten it. Galling is where a soft metal is distorted or abraded by forceful contact with a harder metal. A smooth surface is usually turned into a (microscopic) rough surface and friction increases dramatically. Galling interferes with applying the proper torque to the bolt. To avert this problem, apply a very small amount of anti-seize to the portion of the bolt head that contacts the brass block. Also apply a very small amount of anti-seize to the threads of the bolt. Loosely reassemble the brass wedge clamps, the bolt and the leansteer shaft on the Segway.

To tighten the brass wedge clamps, I use the following procedure to ensure the brass and the aluminum hub are aligned properly:

• Align the leansteer shaft as closely as possible to the hub and tighten the bolt finger-tight.

• Loosen the bolt the smallest amount possible that will let you detect a tiny bit of slop as you rock the leansteer shaft a very small amount from left to right. You should be able to feel the brass blocks contact the aluminum on the left then the right as you rock the leansteer shaft back and forth. Verify that the shaft and the wedge blocks are centered by confirming that the limits at which the wedge blocks contact the aluminum hub are approximately the same point left and right of center (the slop is even on both sides).

• As you are rocking the leansteer shaft back and forth, tighten the bolt the tiniest amount possible so you can detect a reduced amount of slop as you rock the shaft back and forth. Keep rocking the shaft back and forth a very small amount as you tighten the bolt the tiniest bit each time you rock the shaft. Repeat until you cannot detect anymore slop as you rock the shaft.

• Once all the slop is gone, your bolt will still be only finger-tight. Now apply the proper torque to the bolt (Segway says 11 NM or 8 lb/ft). If you are using a wrench that is 3" long, you'll have to apply about 32 pounds at the end of the wrench to approximate 8 lb/ft of torque.

• Rock the leansteer shaft from one extreme to the other several times. If you hear any clicking, the procedure has failed. Start over, ensuring that the shaft is centered when you start. The best way to ensure the shaft is centered is to confirm you have the same amount of slop left and right of center before you start tightening the bolt.

Two final comments. A lot of people don't realize that friction encountered by a bolt can result in improper torque. Torque specs are established in the absence of unusual friction caused by such things as galling or dirt. Anti-seize is designed to allow fasteners to be torqued properly. But don't use a lubricant such as oil or grease in place of anti-seize - this will allow too much torque to be applied and can result in damage to fasteners.

There is another issue that makes tightening the brass wedge blocks difficult. Just as the steel bolt galls against the brass, the aluminum hub galls against the brass wedge blocks. I don't recommend using anti-seize at this juncture though - it is the very friction at this junction that holds everything together.