Rear shock length and shaft ujoint stress

[rafalc]

Answering another post here on the forum got me thinking... I got new 13" rear progressive shocks with the HD spring. With me on the bike, the center of the rear wheel is significantly lower than where the main shaft exits the engine (I would say 2-3 inches lower). The service manual does not talk about the "rake" limits for the rear.

Ideally there would be close to a straight line going from the main shaft (engine side) all the way back down the swingarm at normal ride weight. Should I be concerned about the stress on the U-joint? How are your guys' rear rakes/angles look? I'm thinking of maybe exchanging for 12.5" or 12" shocks.

[The emperor has no clothes]

That's about normal. Nothing to worry about.

[Jims99]

Not sure about the bike angles, but I know for automotive drive shafts they recommend an angle. If too straight, it can cause the ujoint to bind easier Under load.

[hubcapsc]

The pinion joint is kind of a "swivel joint" to take care
of the swingarm action...

-Mike

[pancho]

The bike is designed with 13 in. shocks. With the bike loaded and rider/riders, the proper geometry is had when the shock preload is adjusted so there is 1 to 1 1/2 in "sag" in the rear shock. (learned this through reading many other posts relating to this and the attachments provided therein looking to solve a new seat issue) Although you are probably correct about the ideal condition of the driveline, our bikes run an angle at the u joint as you noted. I wonder if you have the proper "sag" in the rear shecks as you are running the HD versions.