Length vs weight

There is one thing I will add to this, but my thumbs don't have many rules, is a little deal about axle scrub. Going up to a triple axle you really want to watch getting into really tight turn arounds ecspecially loaded. Three axles really do not pivot very good on hard surfaces and also, be mindful of the tail swing. I have seen many near misses, and most of them have been at fuel pumps. Just use a little forward thinking. You will definitely like the tri running down the road, but not so much when it comes time to replace tires.

rexlion wrote:
The OP's sig shows that they have a 5th wheel. So I take it they have traded for a longer 5th wheel. Therefore the discussion about TT towing is not applicable.

People add/change their signatures mid thread...

Personally the rules of thumb about a bumper pull COULD be modified to 5w trailers also. But add in another about 4-6' for being farther forward over the axel vs behind x amount of inches. Or as I also mentioned, heavier chassis rigs can handle longer trailers vs lighter ones.

BUT, we are now into how big/small one can go, going by chassis strength if one will call it that. Then one needs to power it according to how and where you will drive the rig too. Reality is, choosing a given tow rig for a given trailer needs to have MANY factors/rules of thumb to come up with a proper tow rig for any of us. What works for me, may not work the person reading. When I had kids. many would say a 6500 lb trailer could be towed by a half ton. Well, by the time I put 4 adult sized teenaged kids, spouse nd myself in a typical half ton crew cab, I was at gvwr with 1200-1300 lbs of family wt, add in the dog, 150 lbs including crate, hw, rack, canoe, a bike or two or 6.....I needed some 3000 lbs of payload in the TV. That my friends is NOT a half ton twuck! A SW 350 or 25 series truck yes, but not a typical 15 series truck ability.

Marty

JBarca wrote:

tsetsaf wrote:

New trailer is a triple axle.

New trailer is 7' longer.

Truck is rated to handle the weight; should there be any concern about the length?

Hi,

What is the new trailer length? and do you know the TW% of the GVW of the trailer?

Triple axle generally implies higher weights, this many times comes with much longer length.

It may be better if we know what trailer you where up sizing to.

John

H'mm, Towing a 5th wheel. Well that little tid bit would of helped.

We at least had a good review of rules of thumb about a bumper pull...

rexlion wrote:
The OP's sig shows that they have a 5th wheel. So I take it they have traded for a longer 5th wheel. Therefore the discussion about TT towing is not applicable.

Bingo. The new trailer is 44' and has a gvwr of just over 15k. Three 5200 lb axles. Have not scaled it, obviously, but the current owner has the same size truck and judging by the sag it is pretty close on the king pin weight to my current rig. I am not concerned about the weight just the additional 7' of length. Seems to be a non-issue (other than manueverability).

The OP's sig shows that they have a 5th wheel. So I take it they have traded for a longer 5th wheel. Therefore the discussion about TT towing is not applicable.

It is all physics in the end .
A 7 foot longer trailer is a longer LEVER .
The length behind the trailer axles is uncontrolled weight which is trying to throw you off the road .
By having a heavier ROCK ( tow vehicle ) the LEVER has to work harder .
By having a higher percentage of length between the TT axle and the hitch you have more controlled weight and mitigate some of the Leverage behind the TT axle .
Having a Heavy payload Tow Vehicle one can concentrate more controlled weight onto the hitch.
Having a Lighter payload Tow Vehicle restricts the amount of tongue weight allowed to be concentrated on the tow vehicle .
A 9200 # GVW tow vehicle towing an 8200 # trailer is better than an 8200 # GVW tow vehicle towing a 9200 # trailer .
The further aft the trailer axles are in relation to the total length of the trailer the better handling the setup will be .
This is shown dramatically when towing boat trailers which have their axles placed considerably more aft because most current design boats have their engine weight concentrated at the stern .
The best trailer towperson can be helped by good choices in a heavier payload TV pulling a shorter / lighter TT .
Especially if he is taking a nap while letting his kid / wife spell him on a long trip for an hour or so .

tsetsaf wrote:

New trailer is a triple axle.

New trailer is 7' longer.

Truck is rated to handle the weight; should there be any concern about the length?

Hi,

What is the new trailer length? and do you know the TW% of the GVW of the trailer?

Triple axle generally implies higher weights, this many times comes with much longer length.

It may be better if we know what trailer you where up sizing to.

John

While we are on rules of thumb for towing and distances, this one I have a belief in when it applies to towing on the ball behind a TV used for a TT.

"The rear over hang (center of rear axle to center of tow ball) of the TV should not exceed 1/2 the TV wheel base."

There was not any other clarifie'rs to this given as to how long the trailer had to be or what frontal or side area.

Another one was that the trailer weight not be larger than the TV weight. Again no mention to trailer size in relation to the TV.

Many rules of thumb fit a certain set of circumstances that make sense at the time they where developed. When the rule is given again years later, the circumstances most times are not given when the rule is delivered. As time goes by the rules stay however the conditions they are used under do change. Some stand the test of time, others can be quite outdated.

I myself would be breaking the weight rule as the TT outweighs the truck. Not by a lot, but the trailer still wins.

Ron Gratz wrote:

blt2ski wrote:
MIN WB for ANY trailer is 110" ie up to 20'
Then you need 3" of WB per 1 additional foot of trailer length

First -- the "rule of thumb" does not say a TV with WB less than 110" cannot tow any trailer. It just uses 110" as an arbitrary starting number for the "relationship".

Second -- the "rule of thumb", which frequently is attributed to the RV Consumer Group, says 20' TT for 110" WB, and then add 1' of TT length for each additional 4" of WD -- not 1' for each 3".
IOW, all those people with 130" WB Suburbans should not be towing trailers longer than 25' and a 157" WB pickup should not be towing more than 29' (if you want to believe the "rule").

Third -- AFAIK, nobody has ever produced any data or analysis to substantiate the "rule".

Ron

Oh so I am off an inch, not that it matters, I knew it was something like that. As as noted by the fellow with the smallish jeep.....not sure I would use this rule as a hard and fast rule either. If 110" equal 20', to me one would subtract the same WB length ratio going down. So if one has a 102" WB rig, you would limit yourself to 18' or there abouts. RV consumer group was the one to bring this rule out a number of years back.

I also believe if one is going to follow this rule per say. then one needs to figure out the how far behind the RA one is to start with, lengthen as it gets closer to the RA centerline, subtract as it gets farther away. If you have a typical car or half ton truck chassis, this works, if you have a typical 8000-10K 8 lug rig, you can lengthen it some, a dot class 3 some more, on up to a class8.

I am also not sure anyone HAS tested this rule of thumb, or the 2x grawr that I mentioned either, other than someone in the past has noted that these ratios seem to work in some shape or form.

I'm certainly NOT one to follow these at all times.

Marty