npenn wrote: Missing the point IMO, everyone jumped the TV to TT length and skewed the post as it was the only calculation of any importance.
Not everyone was claiming that TV wheelbase and TT length was the only calculation of importance. The OP asked about TT weight. The wheelbase/length debate began with this statement in the fifth post: Wheelbase ratio to trailer length first critical decision. Look online for this ratio but in a simplified form "if your TV has a wheel base of 110" you can tow a 20' trailer and you can safely tow one additional foot for every 4" of wheelbase".
The point is -- "wheelbase ratio to trailer length" is not the first critical decision. The first critical decision should be selecting a TT which is within the TV's towing weight limits.
Quote: We can argue forever about origin, old school, but totally ignoring this ratio is a big mistake. New construction of todays TT are making them longer and lighter, which allows smaller and lighter TV to keep within their GVW while allowing the TV to TT length ratio to rapidly increase. Alarming actually, even with new technologies in the hitch, aerodynamics, suspension, and other aspects of the TT design, bad decisions could easily be made which impact the safety if the TT length is totally ignored as suggested.
I don't think anyone is suggesting TT length should be totally ignored. People are just questioning the validity of the "old formula". There are many people who exceed the formula by 5-7' or more and appear to be doing it safely.
Quote: The bottom line, using the existing formula is a very good starting point (until a new one is calculated), then factor in, new technology hitches, paying attention to TV sizes, matching the TT to TV aerodynamics, and a good deal of common sense, a safe towing environment is sure to be the out come.
IMO, the proper starting point, which seems to be missing from your list, is making sure the TT weight is within the TV's ratings. Unfortunately, when people cite the wheelbase/length formula, they usually don't mention the other factors which should be considered.
I've towed my ultralight in some pretty bad winds. Never had a sway problem even with my previous short wheelbase TV (I don't believe the short WB is NG for towing garbage).
Proper weight distribution and hitch setup is what does the trick.
Now you are always going to feel "push" from high winds, towing or not, but that is NOT sway and nothing will prevent that. Don't confuse the two.
Sway is a continuing oscillation of the trailer caused by the initial "push". If you just feel a single nudge to the side when hit by a gust of wind, that is not sway.
Ron Gratz wrote: IMO, the proper starting point, which seems to be missing from your list, is making sure the TT weight is within the TV's ratings. Unfortunately, when people cite the wheelbase/length formula, they usually don't mention the other factors which should be considered.
Ron
It really doesn't matter if you consider the weight rating of the TV first and then the length-to-wheelbase ratio, or the other way around.
The point is that both are important factors in determining the suitability of a TV/TT combination. If the TT is too heavy for the drivetrain or structure of the TV, the TV is going to suffer. If the weight is too much for the TV to safely tow, then the combination will be unsafe. Likewise, if the TT is significantly longer than suggested by the 'old' formula, the stability of the combination will suffer.
As for modern trailers and modern TVs . . . trailers haven't changed in their basic design since the horse and buggy days. The are boxes sitting on ladder frames sitting on the simplest & cheapest possible leaf spring suspension. A softer suspension will make the trailer ride nicer but that does nothing for making it more stable in cross winds.
Yes, the TV's are better BUT much of the reason a modern 1/2-truck makes a better TV than a 40-year old 1/2-truck is that it's simply a lot heavier. Sheesh, my wife's 2002 F150 weighs 500# more than our 1988 F250. And my 2500HD weighs 2,000# more than the old 3/4-ton Ford. In other words, if you think the modern TV is so much better, then pull a large & heavy TT with an old F250 and then with a modern TV of the same weight. I'll bet the old F250 does a better job of it.
IMHO, the fineries of the definition of sway don't matter. If you're pulling a TT and get hit with a gust of wind that moves the TT sideways enough to be a problem, it's little consolation that it only got blown off the road once & not several times.
Bottom line: if you ignore any of the factors involved in the TV/TT relationship there will be consequences. You might not notice them, but that might just say more about how well you're able to listen to your rig. And not getting into an accident doesn't prove that the combination is safe any more than saying that Johnny's mom let's him do it makes it OK.
Steve & C. J.
"Gracie" the Rough Collie & "Bo'sun" the Bichon Frise
Deus Ex Machina wrote: I've towed my ultralight in some pretty bad winds. Never had a sway problem even with my previous short wheelbase TV (I don't believe the short WB is NG for towing garbage).
Proper weight distribution and hitch setup is what does the trick.
Now you are always going to feel "push" from high winds, towing or not, but that is NOT sway and nothing will prevent that. Don't confuse the two.
Sway is a continuing oscillation of the trailer caused by the initial "push". If you just feel a single nudge to the side when hit by a gust of wind, that is not sway.
Gman22 wrote: ---Where did this formula come from.....honestly? It's been kicked around on the internet for years as if it's gospel.
My thoughts on the subject can be found here. The following is an excerpt from that post:
IMO, we have no clear understanding as to how TT length affects TV/TT yaw stability. However, IMO, it is pretty clear that there are four primary factors which do affect stability. These are:
Tow Vehicle Weight
Tow Vehicle Wheelbase
Hitch Overhang (distance from TV rear axle to ball coupler)
TT Weight The "guideline" attributed to RV.ORG ignores three of these four factors. My guess is that the "data" which were used to formulate the "guideline" might have contained some correleation between TV weight (which might be correlated to TV wheelbase) and TT weight (which might be correlated to TT length).
One could then take an "average" wheelbase for a range of TV weights and take an "average" length for a range of TT weights and come up with a wheelbase-length relationship for "safe" and "unsafe" TV/TT combinations. However, correlations that might have been appropriate for TV/TT combinations which existed in the 1950/60s (or whenever the unknown data were collected) might not be appropriate for combinations in use today.
Bluwtr49 suggested that the "guideline" is ultra-conservative. I agree. IMO, staying within all the TV manufacturer's weight ratings is the primary consideration. If you do that, then the TT length probably will be acceptable also.
Ron
That's what I'm saying. Not to mention COG, moment of inertia, and the placement of the TT axles. BTW Steve, not all trailers ride on cheap leaf springs, a few things have improved since the horse and buggy, and *some* RV makers are progressive enough to use them.
Offline
