Tandem axle... how much wheel travel?

[mdk]

For a relatively mundane tandem axle setup, how much wheel travel will there be?

I'm trying to figure out how much space there must be above the tires for them to go up during extreme articulation. I can't find that information anywhere. I read somewhere you should have clearance for 4 inches of travel, but that doesn't seem like a whole lot. I've been through Dexter's online documents, and a bunch of parts sites and elsewhere, but nobody seems to have this listed.

[Redneck Teepee]

Hope this will help you.

[bobhenry]

Well if dimension "D" says the snubbers hit the frame at 4 - 4 1/2 inches that probably gonna be the max HUH !

[48Rob]

That chart is a good starting point, but you need to measure the setup you actually have, as it may be different.

Measuring between the axle and frame, or "U" bolts and frame will get you close (choose whichever one will contact the frame first).
I always add another inch - inch and a half for the possibility that the outer edge of the tire could rise even further if the wheel on the other side dips into a pothole while the first encounters a speed bump, etc.

Rob

[mdk]

That chart is a good starting point, but you need to measure the setup you actually have, as it may be different.

Measuring between the axle and frame, or "U" bolts and frame will get you close (choose whichever one will contact the frame first).
I always add another inch - inch and a half for the possibility that the outer edge of the tire could rise even further if the wheel on the other side dips into a pothole while the first encounters a speed bump, etc.

Rob

LOL! That's the problem. This is on paper, not real life, and so measuring after the fact can't happen. Was hoping someone had real life experience with a pair of 3500 lb and/or 2000/2500 lb axles and knew how much wheel travel they really have. This is a design for rougher roads and navigating the occasional speed bump and ditch. It's tandems, not for the weight, but for stability and low stress on the tires over rocky / gravel / dirt roads.

I'm expecting a maximum weight of perhaps 3000 lbs, but want the tires to have no more than 50-60 percent of their maximum weight on them and one axle to not "give" if the entire weight gets shifted to it over an obstacle.

[48Rob]

Sorry, didn't see the part about not having them yet.

Point still stands; different setups will have different amounts of travel.
If someone gives you exact numbers, they will work perfectly if you replicate that setup, if not...

Shackle length, spacing of "U" bolts,spring rate, trailer weight, etc, can change the amount of travel.
If you research it and set it up as close as you can, you can use longer shackle links to give yourself extra clearance if needed in the end.

Rob

[mdk]

Sorry, didn't see the part about not having them yet.

Point still stands; different setups will have different amounts of travel.
If someone gives you exact numbers, they will work perfectly if you replicate that setup, if not...

Shackle length, spacing of "U" bolts,spring rate, trailer weight, etc, can change the amount of travel.
If you research it and set it up as close as you can, you can use longer shackle links to give yourself extra clearance if needed in the end.

Rob

on a related question... What's the best way to ensure your alignment is as good as it can be? My thought was a template for the hangers, and then if you have any misalignment it will be production errors in the parts or a slight offset in the tracking, rather than the axles not being parallel to each other.

[Dale M.]

Sorry, didn't see the part about not having them yet.

Point still stands; different setups will have different amounts of travel.
If someone gives you exact numbers, they will work perfectly if you replicate that setup, if not...

Shackle length, spacing of "U" bolts,spring rate, trailer weight, etc, can change the amount of travel.
If you research it and set it up as close as you can, you can use longer shackle links to give yourself extra clearance if needed in the end.

Rob

on a related question... What's the best way to ensure your alignment is as good as it can be? My thought was a template for the hangers, and then if you have any misalignment it will be production errors in the parts or a slight offset in the tracking, rather than the axles not being parallel to each other.

Use a ruler.... Measure from coupler to end of axles... You are forming a triangle with the two long sides equal distance (length), and center of base (axle) should be center of trailer bed... Second axle just follows first axle if all dimensions for first axle are correct...

Dale

[48Rob]

From the center point of the ball/tongue ball cavity to the front of the lead hangers.
Or said another way, from the point of the triangle out on both sides to the spring hangers.

Rob