| Author | Message | ||
     Christian S. Hansen Prolific User Username: enquiring_mind Post Number: 200 Registered: 4-2015 |
Has anyone determined the weight distribution on a Shadow II? What I mean is, if you were to split the car in half along it length, how much weight would be in the front half and how much in the rear half? Total weight is in round numbers 5,000 pounds, but how is it distributed? I am not referring to weight on the axles since the axles are not the same distance from each end of the car. Front axle is nearer to the front than rear axle is to the rear. Clearly the front "half" should have more weight since it contains the engine compartment, whereas the rear "half" has simply a rear seat and boot. Problem is that when I put it into a 20 foot long trailer, there is way too much weight on the trailer tongue, but not enough room to move the car to the rear to take the weight off the tongue. Obviously if I turn around and back the car in, that will shift the weight to the rear since the heavy half of the car will be at the rear rather than at the front of the trailer. It is a matter of distributing the weight properly over the twin trailer axles and keeping too much off of the tongue. Anyone been there, done that? | ||
| Mark Herbstreit Prolific User Username: mark_herbstreit Post Number: 149 Registered: 5-2005 |
Don't do it like this. Think I'd prefer a flatbed!  | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 513 Registered: 4-2012 |
I would load the car on the trailer and then use sand bags to balance the weight happy towing. Richard. | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 514 Registered: 4-2012 |
Christian remember to keep more weight on the front of the trailer to keep it from wagging its tail. Richard. | ||
| Christian S. Hansen Prolific User Username: enquiring_mind Post Number: 202 Registered: 4-2015 |
I neglected to specify that it is an enclosed cargo trailer. I am well aware of weight distribution, but the problem is too much tongue weight rather than not enough. Sand bags won't work as I am already over, or at least close to, the max gross vehicular weight. It is a 7000# trailer which means that it has two 3500# axles. Shadow is 5000#. Trailer empty weight is about 3000#, but some of that 8000# total is on the tongue, not on the axles. I would guess that there is about 1500# on the tongue, if not more. 500# to 700# (typically about 10%) should be proper. The weight drops the hitch level a full 4" and almost lifts the front axle of pulling vehicle off the ground, which leads to poor steering ability!! Today I tried picking the tongue up with my Bobcat skidsteer loader which can easily lift 1500# and it would not budge the weight. The "problem" is the location of the axles on the trailer...too far to the rear. In order to balance the car in the "nose in" position, I would have to remove the rear drop down door and move the Shadow a few feet to the rear. The boot would be sticking out the open end of the trailer by a foot or two which would probably catch the eye of every Highway Patrol Officer who looked my way. I hate making explanations to guys in uniforms with flashing red lights on their patrol cars!! Normally old white guys driving Rolls-Royces are not even on their radar screens, but no doubt that stunt would provoke them! | ||
| Jeff Young Prolific User Username: jeyjey Post Number: 253 Registered: 10-2010 |
If the trailer axles are a bit behind the trailer box’s centreline, it’s certainly worth trying the Shadow back-to-front. | ||
| Christian S. Hansen Prolific User Username: enquiring_mind Post Number: 204 Registered: 4-2015 |
Jeff... Yes, no doubt that is the solution, but that revolves back to the original question as to the balance of the weight distribution of the car itself. If for instance the weight is equal on either side of a halfway point between front and rear of the car that is 50/50 weight distribution (visually on the standard sedan, not LWB, about at the rear edge of the driver door) then turning the car around would have no effect. If however the weight distribution is 60/40, that is, of the 5000# total, 3000# is in the front half and 2000# in the rear, then turning the car around would theoretically shift 1000# to the rear. I will do that experiment over the weekend and then try using the Bobcat again to see how much easier it is to lift the tongue. I was just curious if anyone else had already done such an experiment, or knew the answer. Thanks. | ||
| Christian S. Hansen Prolific User Username: enquiring_mind Post Number: 207 Registered: 4-2015 |
Forgot to give chassis number for 1979 Shadow II SRK37338. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1930 Registered: 6-2009 |
Christian, Just given the significant difference in these cars between the front springs and the back ones I strongly suspect that your 60/40 toward the front is quite likely to be true. I've not seen many cars that have quite the difference that the SY series cars have between the front and back springs. These cars are not, in my experience, fun to tow for a number of reasons. I've only ever had LRK37110 under tow and on a flatbed trailer where the tongue rested on a hitch in the middle of the towing truck's bed and I was not the driver.  Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1262 Registered: 5-2012 |
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| Christian S. Hansen Prolific User Username: enquiring_mind Post Number: 208 Registered: 4-2015 |
Brian...Yes, indeed. That hitch method is I believe called a "fifth wheel" or gooseneck, and does allow for a greater tongue weight since that weight is more evenly distributed between the front and rear axles of the towing vehicle. The problem has now become a moot point due to the occurance of the second problem in less than an hour and twenty miles of driving my new toy. Yes, honeymoon over. Today the radiator top tank burst its seams. Steam and antifreexe all over the entire engine bay and soaking the under bonnet padding. This brings back up the horrible "overheating or not" issue from a year or so ago with my MPW coupe. I'll start another thread on that issue. Geoff...Your photo simply proves that some people should not be allowed out of their cages! It is not that cars cannot be towed, after all it is simply weight in an artistic shape. The task at hand is to arrange the operation such that accidents like this do not happen. Improper weight distribution is quite often the cause. Weight too far to the rear = insufficient tongue weight and resultant fishtailing which can quickly become uncontrollable. Too much weight on the tongue is the same as over loading the rear axle of the towing vehicle which pivots the weight off of the front axle, thus diminishing the ability to steer and likelihood of losing traction on slippery surfaces or when turning. If weight is properly distributed, gross weight towing capacity of the tow vehicle is not exceeded...simply burning out the transmission, or flogging the engine due to insufficient power to maintain speed or crest hills...and finally proper braking system on the trailer without which the brakes oon the tow vehicle burn out, with the attendant undesirable consequences, towing is quite safe and matter of fact. Towing is however NOT something that can be left to "trail and error" in which case the "error" part of that equation becomes evident!! | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1264 Registered: 5-2012 |
Christian One thing that has interested me is when you see RV vehicles towing a small car. This is not something you see in the UK, however I suspect it might be a common sight in Australia. How does that system work? I assume the car must be manual (stick shift) or else it would damage the transmission. Could it not be used for towing a Rolls, with the prop shaft disconnected? How does the steering work? I'm asking as you obviously have a good knowledge of what is involved in towing cars. Geoff | ||
| Christian S. Hansen Prolific User Username: enquiring_mind Post Number: 211 Registered: 4-2015 |
Geoff... Yes, I beleive you are correct in terms of the manual versus automatic aspects. It is my understanding that the rear seals get damaged due to lack of lubrication while towing for reasons I am not entirely clear on...something about the transmissioni actually having to be functioning to pump lubrication fluid to that area. As to the RR, having just acquired another toy, and having just read the owner manual last night, it did caution against towing, but then said it was OK if speeds kept under 45mph and distance less than 50 miles, but then advised to remove the prop shaft in order to be sure to avoid issues. As to the steering issue, apparently the steering wheel gets tied off in the straight ahead orientation and then as the tow vehicle turns, the lateral forces on the front wheels tend to cause the axle to turn just a bit to follow the curve and then straighten out again as the tow vehicle straightens out. If however the front axle is not so secured, it will turn all the way over to the lock and then not recover. I'm not sure how having a steering column internal lock would work as it does not allow the wheels to turn as a curve is sensed with the result being that the tires would be scuffed around the turn. Maybe a bit of scuffing is for the best as preferable to the wheelspulling all the way to lock and then not recovering. Years ago I tried pulling a vehicle with no steering lock mechanism and simply a rope holding the steering wheel and had difficulty with the tires moving to the lock position and not recovering on sharp turns over irregular terrain, so considered it impractical. Maybe the steering lock solves that problem. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1549 Registered: 6-2006 |
It is the bushes and bearings that get damaged. Manual gearboxes use splash to lubricate themselves but auto boxes use pumped transmission fluid. Without the engine running there is no oil feed. Some rvs have hydraulic pumps that feed to quick coupling connectors that lubricate the box but most are manual or have box types that can be towed. So unfortunately you will need to disconnect the propshaft when you hook up your Rolls. A Frame towing relies on the cars castor angle to self centre the steering so the steering wheel is left free to rotate. Some cars just will not self centre as noted. I think many BMWs are like that. Reversing is a bitch though! I used to collect and deliver Shadows and Spirits in London when my workshop was down there. Short distances and low speeds. If seeing a Rolls didn't attract enough looks . . A driverless one caused plenty of double takes.! | ||
| Jonas TRACHSEL Frequent User Username: jonas_trachsel Post Number: 87 Registered: 2-2005 |
To tow a car behind a RV you need an A-frame hitch. The "legs" of the A fixed to the car to be towed somewhere under the bumper. Works as the two axle trailers (not twin-axle where the axles are close together) behind lorries of olde. | ||
| Jonas TRACHSEL Frequent User Username: jonas_trachsel Post Number: 88 Registered: 2-2005 |
How to determine the center of gravity is a simple static calculation, but you need to know the load on each axle. Assuming weight distribution is 60:40 front to rear then the wheelbase length is reverse equally divided by the center of gravity 40:60 front to rear. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1024 Registered: 9-2004 |
Use the cars spec and use this for the trailer nose wieght.will work on two or four wheel trailers for get all the other ways. Bathroom scales will work under the jockey wheel as well. https://www.amazon.co.uk/Milenco-2691-Calibrated-Caravan-Trailer/dp/B004W17D94/ref=sr_1_3?ie=UTF8&qid=1465297514&sr=8-3&keywords=nose+weight Use rachet straps on all four wheels to hold car firm on trailer with out damage to the sub frames unless it has a tow bar for the rear. | ||
| Randy Roberson Grand Master Username: wascator Post Number: 688 Registered: 5-2009 |
Gooseneck is the best possible tow setup. You need more weight in front to avoid the sway. You need plenty of tow vehicle and trailer; at the limit or above greatly increases risk of catastrophe and it happens all too frequently in our hobby. Witness the 1936 Phantom III lost in Europe end of August this year, only the latest. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1407 Registered: 5-2012 |
Hi Randy I would be interested to read this but the link does not work Geoff | ||
| ross kowalski Prolific User Username: cdfpw Post Number: 122 Registered: 11-2015 |
Four down "toading" towing does not require anything holding the steering wheel staight as a matter of fact it makes it worse. The wheels have to unlocked. There are a select few toading autos which all have output shaft mounted pumps.There grand lists of toading cars on RV websites. Can you tow the other kind of auto, sure but you have to keep the engine running! | ||
| Randy Roberson Grand Master Username: wascator Post Number: 690 Registered: 5-2009 |
Geoff I never could get the link right. A hobbyist bought a '36 PIII at a dealer in the Netherlands and left for Switzerland towing it on an open trailer behind a Range Rover. He did not get far. This happened late August and alittle searching should turn it up. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1409 Registered: 5-2012 |
Hi Randy Found it. A tragic sight. http://www.liveleak.com/view?i=6d6_1472413402 Geoff | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 374 Registered: 4-2015 |
What a shame. People like that are the ones who give being an idiot a bad reputation. The good news is that the trailer looks to be in fine shape still. I hope that my assessment is not too blunt, nor too cruel, but it appears that the trailer was too small, the PIII was not tied down properly, and of critical consequence due to the axle(s) of the trailer placed at the center of the trailer (see 21 seconds and about 34 seconds) it was probably impossible to get proper weight distribution...i.e not enough tougue weight. It is not clear if there are two axles on the trailer or only one. For the weight of a PIII, two axles with at 7000# capacity would have been absolutely necessary. If the trailer had only one 3500# axle, that PIII would have been a severe overloading and another error which could have led to a broken leaf spring or blown tire, although in those cases probably would not have had these results. The fish tailing caused by too much weight to the rear becomes uncontrollable so quickly that I would bet that was the cause here. Again, what a pity. | ||
| Martin Taylor Frequent User Username: martin_taylor Post Number: 57 Registered: 7-2013 |
https://www.facebook.com/Trustmeiamamechanicalengineer/videos/822426531232285/ Some good info on towing in general | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1166 Registered: 5-2015 |
I dont tow any cars I have them put on the back of a purpose built truck. Which is properly insured with a skilled operator. seen lots of trailer accidents. To find weight split front to back, go to public weigh bridge and pop the front wheels on only then the back and do the arithmetic. I think its near 50/50. if the car is jack up via the jacking ports front and back wheels will lift off on the side being jacked. thats about centre of car. | ||
| John Beech Experienced User Username: jbeech Post Number: 33 Registered: 10-2016 |
I read this thread with interest because I recently brought Tootsie home from south Georgia to central Florida on a flatbed trailer without a hitch (pun intended). And I thought everyone knew the answer. Anyway, I believe the answer lies before your eyes because Rolls-Royce engineers in their wisdom fitted a pocket in the sill where the jack is fitted and it's where - in my opinion - the CG of the unladen automobile exists. Or close enough for government work. We used this as the datum when loading Tootsie and the hitch squatted the perfect amount. This, admittedly is a judgment call, but one that has served us well for not just decades but generations because Keith and I both learned the art of loading and towing from our respective fathers. And the lore of loading and towing is well distributed throughout America because we, as a nation, are a group of people that routinely tows boats, trailers, cars, household goods, etc.  | ||
| ross kowalski Prolific User Username: cdfpw Post Number: 176 Registered: 11-2015 |
John, Is that a u-haul trailer? | ||
| ross kowalski Prolific User Username: cdfpw Post Number: 177 Registered: 11-2015 |
https://www.youtube.com/watch?v=fWd8ml9mFMo | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 418 Registered: 4-2015 |
John... "I thought everyone knew the answer... Perhaps you misread the original question that precipitated the thread, so I restate: Yes, the factory has placed the jacking point such that it is at the 50/50 point where half of the vehicle's weight is ahead of that point and half behind it so that when the vehicle is jacked at that point the entire side lifts up and is balanced fore and aft (assuming no dead bodies or bags of cement in the boot!). On the other hand, the ORIGINAL question was whether the "measured" midpoint...that is, the length of the vehicle divided in half...coincides with the "weighted" balance midpoint (the jacking point). My suspicion was that they are not the same points given that more of the total weight of the vehicle is in the front engine compartment than the boot. I did not have a vehicle with which to check at the time the question was posited, but if you observe yours and determine the measured midpoint of the length and compare it to the location of the jacking weighted balance midpoint and report back, that would provide the desired answer. Thanks. | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 421 Registered: 4-2015 |
Ross... That video is a perfect illustration of the problem that the naive set themselves up for by having insufficient tongue weight and is undoubtedly exactly the fate that befell that PIII. The fishtailing happens so quickly that it is truly shocking. | ||
| John Beech Experienced User Username: jbeech Post Number: 34 Registered: 10-2016 |
Ross, yes, it is indeed a U-Haul trailer, and in my opinion it is a fantastic piece of design engineering. The ramps conveniently slide and stow within slots in back (there are latches to lock them in place and nylon straps to aid easing them out and into position. It's equipped with an inertial brake setup and thus, there's no need to equip the customer with an accessory electric brake controller (with which our tow vehicle is equipped but that few ordinary vehicles may have). Securing the load is easy because it's equipped with a ballistic-nylon webbed-strap system that slips over the front tired and ratchets in place to capture and secure them such that setting the parking brake has you ready to go - though we used additional straps because we're familiar with both Murphy's Law and Sod's Law. Meanwhile, the structure is made of galvanized steel for long life, it has dual-axles for added safety in the eventuality a tire fails, and the best part? It cost just $83 for the one-way rental. Frankly, unless you tow very, very regularly, I fail to see why anyone would possibly want to own a trailer. Not when they could rent this instead. Very much recommended. Christian, I measured Tootsie (SRX6816) and from the center of the jack point to the furthest aft part of the rear bumper is 112" and to the furthest forward part of the front bumper, she is 93" long, or 205" overall length. The midpoint, or 102-1/2" is quite obviously not in accord with the jacking point. Add to it, the wheelbase is 120" and the jack point is 58-3/4" aft of the front axle versus the exact midpoint of the wheelbase, e.g. 60". Thus, the jackpoint is not at the vehicle overall length midpoint, nor the wheelbase midpoint. It's not even close. Last thing, in my estimation Tootsie is possessed of a 3-body trunk (in today's units), or four 1969-vintage bodies. Cavernous even by the standard of a Lincoln Continental or Coupe DeVille. | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 682 Registered: 4-2016 |
John, Huge trunk (or boot as we call them here in Oz) For sure, but compared to Australian made cars going back ages, I really lacks depth. We could certainly fit 6 here, double stacked rows of 3, even wrapped in shag pile carpet!! I struggle with a big esky in this boot, so had to purchase different more lower squatted type coolers. | ||
| ross kowalski Prolific User Username: cdfpw Post Number: 185 Registered: 11-2015 |
John, I agree about the u-haul car carrier, I use them whenever I can. They are $54 for 6 hours here in MA which if you pick it up at the right time is actually all night! I recently picked up a xj6 with one and my friend who went along sold his 22' double axle the next day. He figures he spends that in registration. They have two drawbacks as far as I can see. the first is that because they strap in the front wheels, you cannot adjust the tongue weight on the tow vehicle or the weight distribution on the trailer. It is OK to play free and loose with tongue weight and weight distribution with little loads, but with real loads it becomes real serious. My f250 was doing farm duty recently towing 19,000lb loads on a double axle. It is really nice to have the flexibility of moving the weight fore and aft to get a safe ride. The second is they have a weight limit of 5k which makes them only good for passenger cars. Unless you have to move a Grosser in which case it is easier to change residences than to move the car. What I like best is the fold down fender. I have crawled out of many a window on equipment trailers doing car duty. I had to borrow a 1500 chevy v6 with only front brakes to get the Jag the other day as a friend was borrowing my truck. The pickup was a little light for the job, but was able to do 55 the entire way with no problem (though I did a lot of transmission braking) Also, regarding trailers I towed truck bed on a toy harbor freight utility trailer the other day with negative 2 or three pounds on the hitch. It had a miserably short tongue to axle distance as well. It was fine to 45 then instantly started wagging, 44 fine, 45 yikes. I guess it goes to show how quickly one ends up in a ditch with something like this. | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 316 Registered: 11-2015 |
John and Robert, You are right about the jack point being very close to the CG and weight distribution being near 50/50. I forget the deal here, but I jacked the car with both wheels off and it lifted evenly. Based on the tires on the roof and the huge rubber leaning on the bumper, I am guessing that I was mounting smaller tires.  Also, here's the picture of the incorrectly loaded trailer I moved that pickup bed on. It actually pulled up on the tongue.  | ||
| Patrick Ryan Grand Master Username: patrick_r Post Number: 1205 Registered: 4-2016 |
Ross, The "there I fixed it guy" We need you here in Oz. |
