How to determine axle location?

[Tackett]

I'm about to start a 5' x 10' TD, heavily influenced by the Grumman II. I've searched, and haven't seen an answer yet - how do I determine where the axle goes if I don't know how much things weigh?

Thanks,
Tackett

[halfdome, Danny]

I'm about to start a 5' x 10' TD, heavily influenced by the Grumman II. I've searched, and haven't seen an answer yet - how do I determine where the axle goes if I don't know how much things weigh?

Thanks,
Tackett

I found this in sdtripper2's Index at the top of the page where all the goodies are listed. Danny


Axle placement
http://www.tnttt.com/viewtopic.php?t=4709
http://www.tnttt.com/viewtopic.php?t=1223

[angib]

A universal number you could use if you've no other information is to put the axle 37.5% of the body from the back - with a 10ft long body, that's 45" from the back of the body. Note that the measurements are from the back of the body - if your frame is shorter than the body, it won't be 45" from the back of the frame.

If you want to put a lot of heavy stuff in the galley, reduce that dimension to 42" (=35% of length). Or, if you want to add a heavy tongue box, increase the dimension to 48" (=40% of length). If you want a heavy galley and a tongue box, leave the dimension unchanged.

This can only be an approximation - you may need to alter where you carry stuff in the trailer to get the balance right.

Andrew

[Tackett]

Thanks for the info, guys.

I like the ballpark figures, as it's really hard to measure the weight of something that isn't built yet.

[wannabefree]

I went with about 40% and am glad I did. One thing you can do is plan on not deciding where to put the battery until the trailer is built. I ran heavy gauge wire to the front, center, and rear of the trailer so I could put the "ballast" where it gives me the best effect. I'm not done yet, but it's looking like the back end will be the spot.

[aggie79]

I went with about 40% and am glad I did. One thing you can do is plan on not deciding where to put the battery until the trailer is built. I ran heavy gauge wire to the front, center, and rear of the trailer so I could put the "ballast" where it gives me the best effect. I'm not done yet, but it's looking like the back end will be the spot.

That's what I'm doing too for the same reason. Also, sometimes we will carry bikes on the back of the teardrop, and when we do, Ill move the battery to the tongue box. (I plan on adding a battery selector switch so I don't have too much electrical work to move the battery.)

[Tommy2tone_1999]

Don't mean to hijack the thread, but it is under the same topic. I'm thinking that it's gonna be difficult to place the axle for me. I want to build a 5x8 BenRoy on a 4x8 HF trailer. This means I have to get it right before I put it together because I have to cut wheel wells for the floor and walls. Any pointers to help me ?

[bobhenry]

By lengthening the tongue you can adjust the balance point without moving spring perchs. I have "chubby" built on a modified harbor freight frame and he dances at 65 mph indicating some balance problems here is the fix I intend to use to fix it.





Thanks again to Harvey " NOBODY"

Get the frame ready to tow and back it down the driveway if it is a pain in the ass to back up it will be a bad boy on the road. ( my opinion)

[madjack]

Bob, don't wanna bust your bubble but lengthening the tongue will not appreciably affect the wheel/tongue balance point...unless you add a 20' tongue and then the weight of the steel will make a diff...the only way to appreciably affect the balance is to move the axles or redistribute load...my "rule of thumb" is to place axle at 3' on an 8' trailer and move back 4"s for each foot of length added...that gives a 44" placement on a 10' unit...pretty close to Andrew's numbers.....................
madjack

[Tommy2tone_1999]

Is that 3' from the back of the trailer?

[madjack]

Is that 3' from the back of the trailer?

...from the back of the body...not frame...............................................

[Tommy2tone_1999]

COOOOOOL Thx

[prohandyman]

Tackett
This is how solved the problem. Adjustable mounting plates. One welded to the frame and one welded to the spring mounts, and a series of holes thru both so I can shift the axle after the trailer is complete to obtain the tongue weight I want. Of course this only works if you mount the fenders after selecting axle location.

[bobhenry]

Bob, don't wanna bust your bubble but lengthening the tongue will not appreciably affect the wheel/tongue balance point...
madjack

adding 32" to the tongue greatly changed the tongue weight.

control when backing was greatly improved.

general towing also improved.

How would the tongue weight increase dramatically if the balance had not been altered.

Just asking

[madjack]

Bob, adding 32" to the tongue, added 32" worth of steel weight to the tongue weight...and that's all...of course, all of the steel involved in the lengthening is added as well...the weight on your wheels has not changed except to possibly going up VERY slightly...lengthening the tongue, changes the geometry in relationship to the wheels and this will give an increased ease in backing(longer tongued trailers back easier) and better handling...basically(and within reason) longer tongues are better than short ones for most applications.................
madjack