Ron_Gratz
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Re: WDH - how much does it reduce tongue weight?
rbpru wrote: I recall a post showing a WD hitch add with a front wheel drive Oldsmobile Torinado with the rear wheels removed towing a travel trailer. If the WDH manufacturer added enough weight behind the TT's axles, the TT could have had a negative tongue weight. If the TT has enough negative TW, the WDH doesn't need to transfer any additional load from TV's rear axle to the TT's axles. More likely, the TT's negative TW would be chosen to leave a small amount of rear-end sag (perhaps an amount of sag similar to that produced by 1000# TW} and the WDH would be adjusted to eliminate that remaining sag. Ron1KViews0likes0CommentsRe: Too much WD bar?
Huntindog wrote: My setup has worked very well for many years and tens of thousnds of miles... I'm not gonna stress over this "new" thinking. This is not "new" thinking. IMO, the idea of basing WD bar rating on TV cargo plus TT tongue weight it is a holdover from 50-60 years ago and does not apply to modern tow vehicles. Ron719Views0likes0CommentsRe: Too much WD bar?
In theory, a WDH can be used to cause some of the weight of TV cargo plus TT tongue weight to carried equally on the TV's front and rear axles with the remainder of the weight transferred to the TT's axles. For example, 30% of the combined cargo plus tongue weight could be carried on the TV's front axle, 30% on the rear axle, and 40% on the rear axle. This approach to WD was commonplace 50-60 years ago when the typical tow vehicle was the family sedan. WDH manufacturers recommended that WD bars be rated for combined TV cargo (usually cargo carried in the TV's "trunk") plus the TT's tongue weight. It was assumed the bars would be adjusted so that equal load would be added to the TV's front and rear axles. Now, most TV and WDH manufacturers do not recommend the "equal squat" approach. Instead, they usually recommend that between 0% and 100% of the load which was removed from the TV's front axle should be restored via WD. IOW, there should never be any net addition of load on the front axle, and there could be a front axle load reduction equal to as much as 40-50% of tongue weight. Obviously, if you load the WD bars so the TV's front axle is subjected to zero net load, the bar load will be much less than if you adjust them to transfer a load equal to 30% of cargo plus tongue weight to the front axle. If you follow the modern approach of restoring not more than 100% or removed load to the front axle, there is no need to size the bars based on cargo plus tongue weight -- using tongue weight alone is more than adequate. If you follow the recommendation for a 50-60 year old family sedan, you might want to base the bar size on cargo plus tongue weight. Ron720Views0likes0CommentsRe: Second Opinion, and a few questions
Aron wrote: So, here's my situation: my tow vehicle has a payload of 1364 lb (per the yellow sticker). Wheelbase of 119", and estimating 60" between the ball and rear axle. I don't have a trailer yet, but I'm currently considering one with a dry weight of 5160 lb (GVWR of 6500 lb). I don't have good measurements on the distance to the rear axle. The trailer is 28'3" long, with an approximate 24' box, so I'm assuming (based upon photos) that the axles are centered or slightly behind the midpoint of the box, which would give a distance from ball to axle midpoint of approximately 195". I'm thinking of purchasing a Blue Ox Sway Pro 10,000 GTW, 1,000 TW hitch (shipped weight of 96 lb according to the website). It appears that the spring arms are 29" long. So, assuming that I can properly tension the spring bars to provide a full 2000 lb of load, that should generate approximately 297 lb of load applied to the trailer axles, correct? If I'm remembering my statics correctly, that means that 297 lb of load from the tongue would not be applied to the payload of the tow vehicle, correct? So even if I load the trailer to full 6500 GVWR, and load the trailer tongue to 780 lb (12%), I should not exceed the payload of the tow vehicle, correct? (1364-96-780+297=785) My family currently weighs 585 lb, so that still leaves me with 200 lb of payload buffer in case I can't tension the WDH fully, or if the trailer axles are further back than I think. And assuming that they grow another 100 lb or so, I would still have a 100 lb buffer. And that looks like a worse-case scenario, because I also wouldn't be fully loading the trailer to capacity. Does all of that check out? Or is there a flaw in one of my assumptions? Thanks! With a TT which is 28' overall, I would recommend a tongue weight percentage of 13%. For a TT weighing 6500# the corresponding TW, at TW% = 13%, would be 845#. Based on your dimensions, a TW of 845# would cause a load of approximately 845*60/119 = 426# to be removed from the TV's front axle with no WD applied. If you want to follow Ford's WDH-adjustment spec which calls for restoring approximately 50% of the load which is removed from the front axle, you would need to adjust your WDH to restore about 213# to the front axle. Again, using your numbers, to restore 213# to your front axle would require the WDH to be adjusted to transfer about 213*119/(60+195) = 99# to the TT's axles. The corresponding load applied by each WD bar would be about 99*195/29/2 = 333#. If you used 1000# rated WD bars and adjusted them to transfer the previously calculated 297# to the TT's axles, the corresponding load transfer to the TV's front axle would be about 297*(60+195)/119 = 636#. This is significantly more WDH load transfer to the front axle than is specified by Ford. Ron531Views0likes0CommentsRe: Second Opinion, and a few questions
Aron wrote: There's one piece of Ron Gratz's WDH thread that I'm still not clear on. I understand all of the physics/math involved, but it's just assumed that the two 1000# spring bars generate 2000# of "load". Is this supposed to be representative of a system such as a 10,000 GTW/1000 TW system, or one more like a 20,000 GTW / 2000 TW system? A pair of 1000# WD bars (two bars rated at 1000# each) typically would be used with a tongue weight in the neighborhood of 1000#. The amount of load applied to the bars is determined by how "stiff" the bars are and by how much you make them "bend". The magnitude of load which could be transferred to the TT's axles would be determined by 1) the combined chain load applied to the two bars, 2) the effective length of the bars, and 3) the distance from ball to midpoint between TT's axles. Assuming a load of 1000# applied to each bar, effective bar length of 30", and ball to axles distance of 200#, the amount of load transferred to the TT's axles would be approximately 2*1000*30/200 = 300#. Let me know if you have specific questions about how to determine trailer-induced load acting on the tow vehicle. I'm always happy to crunch some numbers. Ron530Views0likes0CommentsRe: Anderson no sway hitch
hvac wrote: I drop the coach on the ball and then tighten to just around 5 threads showing. then drop it all the way. It seems to perform best with that number showing, but honestly with air suspension on our eco diesel I have not even used the chains and it tows great around town or on country roads. Highway and semis need the anti sway effect and and it does a great job. ---Salt and mag chloride get caught in the triangle/shaft and man it can squeal like scared pig. WD 40 spayed carefully on that region works but be careful not to get near the ball, as that is your anti sway. If you use the Andersen hitch without the chains, you will get no "anti sway" effect. This is explained very well by our Moderator in this post. You can go ahead and put WD 40 or a lubricant on the ball. Just don't use so much that it runs down onto the friction material. The sway resistance is not generated between ball and coupler. The sway resistance is generated between the ball shaft and the friction material -- but only when the chains are used to force the ball shaft to rotate relative to the friction material which holds the shaft. Ron369Views0likes0CommentsRe: Look at my hitch set up please....
lukenick wrote: ---I do believe they sell the Eaz lift Recurve R3 and R6. Those would also work out great for my situation because the round bars go on top. Let's see if they will swap it for me.--- Seems to me the Recurve would be the ideal hitch for your situation. Ron462Views0likes0Comments
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