Fork Compression when Strapping it Down.
 

Loaded bike in back of truck tonight. Taking it on vacation while pulling camper. Wondering how much one should compress the forks on a HD Lowrider? Seemed to ride fine for the short distance I tested it.

I compress them a few inches but nothing crazy, no need to blow a fork seal. I also use 4 straps up front though, and 2 in back.

A couple of inches usually works. Use a rear strap just to keep the back end from walking around. When you strap the front down, give the bike a bounce and see if it's stable side to side; if not tighten the straps a bit more. Compress just enough, too much and you can blow seals.

When I used to transport my Vulcan 750 in my pickup. I just compressed the forks about 3-4 inches, and never had a problem.
Last year my bike wouldn't start, so I called the AMA road service. They sent a guy with a nice rig that pulled the bike up. Then he put some cups on the handlebar ends and started ratcheting . And ratcheting . And ratcheting. And I kept thinking WTF is he doing. But he had just been bragging about how they towed for Harley dealers, and I felt stupid calling him out.

He tows me a half mile to go my Indy, and lets the bike down and my Handlebars are bent down about 6 inches. I complained to the AMA, and the tow company paid for the $135 repair. Next time I will speak my mind.

Not at all. I strap my road king where the front fender bolts to the fork and strap rear tire from jumping from side to side.

Compress it enough the front end can't bounce but don't bottom it out, too loose and the bouncing will work the straps loose over time.

Make sure that the front wheel can't move side to side and, the straps won't come loose from the bars. A couple inches should be enough.

If you find yourself doing this a lot consider a wheel chock. It helps eliminate all doubt.

Esp from these guys--Condor

I am going to be original here and say...a couple inches.

I've hauled bikes thousands upon thousands of miles tied down in the back of a pickup since 75. Cranked 'em down so they won't fall over and have never, repeat NEVER, blown a fork seal. To those that think tying a bike down with the forks compressed more than 2" will blow a seal, I guess bottoming out on a ride would blow the seals then, huh?