Axle minimum overhang - why?

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Axle minimum overhang - why?

Postby SantaFeTrailer » Thu Jul 13, 2017 11:05 am

Folks,

I am considering replacing the drop axle on my 5x8 CTT with a straight axle and running wheels to match my TV. The current drop axle (Dexter 3500 w/ brake flanges but no brakes) has an overhang (distance from center of spring perch to face of hub) of about 7.5". The new axle I am looking at (Dexter 3500 w/brakes) has a listed minimum overhang of 14", which seems excessive - it would put the inside of my tires about 8-9" away from the sides of the trailer.

I haven't been able to unearth an explanation of the minimum overhang requirement other than what Dexter gives: "Minimum Overhang dimensions are based on zero offset wheels and physical clearances; and are determined by suspension type, wheel and tire combination." Note that this response seems to indicate that a flat 14" minimum overhang requirement doesn't really mean anything if they don't know the wheel and tire types.

I asked Southwest Wheel the question, and they say only "Toyota rims are not approved for this axle.  The center bore, offset, and capacity will cause problems."

I have done plenty of research and feel comfortable about the center bore (Toyota rims are lug centric, and I found lug nuts that fit the Toyota wheel but also fit the trailer hub studs). I can see offset being a problem if it resulted in an overhang *greater* that the allowable spec (it won't). Capacity isn't an issue at all (remember, 5x8 CTT).

So... does anyone want to tell me that there is a real reason for the minimum overhang and I will die a firey death if I just order the axle?'

'Thank you.
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Re: Axle minimum overhang - why?

Postby working on it » Thu Jul 13, 2017 12:16 pm

SantaFeTrailer wrote:Folks, I am considering replacing the drop axle on my 5x8 CTT with a straight axle and running wheels to match my TV. The current drop axle (Dexter 3500 w/ brake flanges but no brakes) has an overhang (distance from center of spring perch to face of hub) of about 7.5". The new axle I am looking at (Dexter 3500 w/brakes) has a listed minimum overhang of 14", which seems excessive - it would put the inside of my tires about 8-9" away from the sides of the trailer....
  • Dexter's 14" overhang is the total from both sides (14"=7"+7"). Your present axle would've been listed as having a 15" overhang.
  • axle overhang description - Redneck Trailer.PNG
    axle overhang description - Redneck Trailer.PNG (68.65 KiB) Viewed 202 times
    how overhang is determined
  • I ordered a straight, no camber, w/brakes & E-Z Lube, 3500 lb axle from Dexter, giving them my spring center measurements. I was sent an axle that was exactly what they said it would be, from an earlier thread
    working on it wrote: I sent an inquiry via e-mail last Saturday, giving my specs (based on the Dexter ordering measurements, found on the Redneck site). A rep responded Monday, saying that Dexter could not build/weld one to my specs, and that I would have to extend my hub face from 61.25" to 63.75" before they would weld the spring seats on. After responding to that, by asking what spring center measurement would match the 61.25" hub face, he answered 47", on Tuesday. I am stuck with a 48.75" spring seat distance, having already built to that spec, so I dragged the wife out to the garage when I got home from work, to help me accurately measure wheel and hub face expansion alternatives. I had her hold a wheel vertically (using a square, for accuracy) with the tire at the maximum distance outward (while still under/inside the fender), while I measured the hub face gained from moving the wheel to that maxed-out position. Luckily, the Dexter-quoted 63.75" is exactly that!
  • axle specifications.png
    axle specifications.png (249.42 KiB) Viewed 202 times
    the decimals are wrong; actually .70 is .75
  • My original measurements were my attempt to duplicate what my first axle set-up was, but that was without brakes. Dexter needed extra overhang in order to add them. It oly added a little to the width, and still had my tires sitting under the fenders (when I bought larger, wider LT tires later, I had to add fender flares).
  • tire clearance first axle vs second axle.png
    tire clearance first axle vs second axle.png (323.02 KiB) Viewed 202 times
    some added width, with extra clearance
  • Since you already have 7.5" overhang, per side, see if 14" total will be enough, or specify more when you order the new axle.
  • 2013 HHRv,"squareback/simple" TTT, semi-offroad? 4x8, 2000+ lbs travel weight
  • featuring: 3500 lb Dexter axle w/brakes & HD leaf spring system > riding on General Grabber 27x8.5-14LT tires, LED lighting inside, A/C & heat, AGM battery 12vdc, 110vac from extended run generator onboard or park power, Coleman dual-fuel stove & Northstar lantern
  • 147697148333
  • 148599125895148106
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Re: Axle minimum overhang - why?

Postby SantaFeTrailer » Thu Jul 13, 2017 1:52 pm

Thank you Working, very helpful. I appreciate it.
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