I read with interest the numerous posts on our Intrepids and thought I would try and pass on some information about them. It always amazes me how much people know about a combination that they have never driven. I have likely driven more combinations of tow vehicle and trailer under more conditions than anyone but I still have to get behind the wheel to know for sure.
If you will bear with me through this, you may find some information you can use no matter what vehicle you choose to tow with. Understandably many of you have concerns about using a sedan to tow with and if 27 years ago someone had told me we would be towing with cars with 212 cubic inch engines that were 3' shorter and 1000 lbs lighter I would have been sceptical as well but for us it has been a gradual process.
Unlike many people in the industry we have always travelled and used Airstream for vacations and for many years we picked up all our units up at Jackson Centre. As well we always have combinations set up here for test drives which is something no one else does. If those demoís donít work well we donít sell many Airstreams. Here around the Great Lakes it is almost always windy and it makes for a great learning exercise. Mr Matheson who started Eaz-Lift was a friend of my fatherís partner before our store opened in 1970 and impressed upon us how important precise hitch set ups were so we have always been very particular about hitchs. Every combination that leaves our place is setup precisely on a level pad in the shop. This is very important no matter what your tow vehicle is and yet if I walk down a row of 100 trailers at the International Rally I will not find 5 conventional hitches set up optimally.
In the 70's we were like everyone else when it came to selecting a vehicle. You bought the biggest car with the biggest engine and if you came to our store in 1976 you would have found a huge Pontiac with a 185 HP455cid engine connected to an Airstream for test drives. The 1977 cars were 2' shorter and 800 lbs lighter with only 350 engines (which turned out to be 170 HP) we wondered how would we ever tow with them? We brought in a 1977 Caprice and connected it to a 31. Iíll never forget the look on Dads face during that first test drive, he was amazed because it handled fantastic compared to anything we were used to. Trucks bothered it about half what they did big old cars it gave outstanding fuel mileage and had more power. This was because it was not using all its power just to pull itself. This was a real awakening for us. Here everything we had ever assumed about tow vehicles had just been thrown out the window and so we started to challenge other assumptions we had made. Looking back now we know that though the car was 2' shorter the wheel base was only reduced 5", the tires were smaller but the wheel rims were actually larger and the suspension had been tightened up the body structure strengthened all these factors combined to make a much better handling tow vehicle. We started to see if we could improve it further for example the tires looked small so we put on a size larger. Well the handling went out the window the power and mileage were reduced so we decided to try a low profile performance tire and everything improved as time went on we added suspension sway bars improved shocks and eventually had those Caprices refined about as far as they could go. We did not keep track of numbers in the early days but I would guess that we set up several hundred of those Caprices. In 1982 Dad entered a Caprice and 34' Airstream in Trailer Life Magazines fuel economy challenge and easily won his class with 14.47 MPG most other combinations of the same size turned in about 8. Funny it was called the first annual economy challenge but they never had another one.
In 1985 they were downsizing again the full size Oldsmobile had a 231 cubic inch V6 but with multiport fuel injection so it equalled V/8 Caprice for power, it was 2' shorter again but it also was getting rack and pinion steering, independent rear suspension and way shorter rear overhang. I thought we should get one to try out and a long term test but Dad did not see the point since the Caprice worked so well. I ordered one anyway, it arrived while he was away on a trip so when he returned there it was connected out front. He came in about 2' off the floor saying something about I told you not to order one of those followed by something about my genealogy. I just said ďdrive the carĒ he came back hooked and I rarely got to drive that Oldsmobile. That Olds towed Airstreams over Independence pass in Colorado to California, Newfoundland, Florida and did hundreds of test drives and by the way that same Olds is still on the road with 200,000 miles on the original drive-train. This carís performance really blew us away, the multiport injection did not lose near the power at elevation that the old engines with carburetors did mileage was 15 towing if you took it easy but 30 mpg was easy solo though the peak horsepower and torque were no higher than the V8 the power-band was much wider so performance was better. However it was the handling that really amazed us. Trucks could literally sneak by without you knowing they were there, the rack and pinion steering communicated road feel back to you so you did not inadvertently induce sway and the body structure was like a brick allowing the hitch to do an ideal job transferring weight. When we put a hitch on these cars the front of the hitch is between the back wheels instead of being on the last 10" of the frame like truck hitches are. Because we fasten the hitch over such a wide area, the installation is extremely solid and free of the flex that gives you the surging ride in many vehicles. In our own tests our hitch will withstand more force than any factory hitch that we have tested. We have set up more than 500 GM front drive cars for towing since 1987.
When the Intrepid was introduced Chrysler had designed in many ways the ideal tow vehicle they just didnít know it. They widened the stance, lengthened the wheelbase and shortened the rear overhang. As well the 214 Horse Power 212cid engine has 4 valves per cylinder which lets you have your cake and eat it to, it has great low end torque but also plenty of horsepower when necessary, as well they gave it an overbuilt transaxle and a 3.67:1 final drive ratio. Our 1994 Intrepid currently has 84,000 very hard miles on it on the original drive train with the vast majority of these miles towing which includes a thousand test drives, hundreds of runs down the drag strip and plenty of trips elsewhere.
Of coarse you can purchase many vehicles with much higher tow ratings but many of them are inferior tow vehicles. Some vehicles with 8000 lb plus ratings are literally dangerous with a trailer on unless you use a Hensley or Pul-Rite and even then they are marginal. Some vehicle segments all have the same rating. For example every mini van ever made by every manufacture carries a 3500-lb tow rating, it is hard to believe that all those vans have identical towing prowess. If you dig into it further, you will discover that there is no standardized test for determining tow ratings. If there was, I donít really know how you would develop it. A 8000-lb 34' Airstream with six 12" brakes, independent suspension and a low centre of gravity easily out stops and out handles a 5000-lb conventional trailer. It tows easier as well since it has half the wind resistance. On our slalom test we can run the Intrepid with a 34 & Hensley through almost as fast as some vehicles with high tow ratings but also high centres of gravity can go through solo.
Of coarse these days everyone wants to sue everyone else and the RV industry is afraid of getting involved with towing issues and have turned it all over to the vehicle manufactures who really are in a tough position. When I set up an Intrepid I have control of the entire process or I donít do it. We know how it will be wired, we only install positive acting brake controls Hydraulic, Jordan or the equivalent, I know the towing dynamics of the trailer, we have control of the hitch system and how it is set up and we test drive every combination. The vehicle manufactures have none of that control. Knowing what I know about how poorly the vast majority of trailers are set up how lousy most brake controls are and how badly balanced some trailers are, if I was a vehicle manufacturer, I would rate everything zero I would not want anything to do with this industry. When someone comes along with something that can vastly improve the safety like Hensley the RV industry treats them like dirt and wishes they would go away. Even Airstream who could double their sales if they would just option and recommend a Hensley and a good brake control to their customers are scared to death of towing issues. At one of my diatribes at dealer meeting I said you all run around here talking about movie star Airstreams and how neat Airstream are to look at just donít ask any of you to demonstrate towing one. But enough of that.
So if tow ratings are not a reliable measure of how well vehicles tow then you would need a better system for assessing vehicles. Over the years we have developed a 6-step process that we go through.
Step 1) Is torque for initial acceleration and steep hill climbing. This is a relatively simple calculation where you multiply the engineís torque by the first and final drive ratios and then divide by the tire radius. This tells you how much torque you can lay on the road. We divide the weight by this number and we would like to come out less than 7 lbs per foot lb available. If I lived in a very hilly area and was constantly pulling steep grades I might want this down around 5 lbs.
Step 2)The question I get asked all the time is ďwill it tow it in the mountains?Ē My usual response is donít worry about the mountains itís the 3 days across the prairies into a 25-mph head wind that are often the challenge. Where as weight only has to be addressed when accelerating or climbing aerodynamic drag has to be overcome every foot of the way. For this we need horsepower and more importantly enough horsepower at cruising speed in direct gear. Towing an Airstream with a sedan we would like to have at least 100 horsepower at 55 mph in direct gear, 140 if towing with a truck, 180 for a conventional trailer and 200 for most fifth wheels. Interestingly the rolling resistance and Aerodynamic drag of the Intrepid and Airstream combination is only slightly more than a heavy duty truck solo.
3) Will the chassis of the tow vehicle be overloaded? For example we cannot tow a 34' slide-out on an Intrepid because with 1500
lbs of hitch weight it overloads the carís suspension. Most Airstreams if set up properly only put 150 - 200 lbs per tire on the tow vehicle. This is a much bigger issue with fifth wheels where so much weight is carried on just the back axle of the tow vehicle.
Step 4) Will the vehicle last? For this there is no substitute for long term testing, generally the transmission is our biggest concern but since the same transmissions are often used across many model lines we can apply what we have learnt about one vehicle to another. For example the most popular vehicle we have used in years is the Ford Windstar Van. We have set up over 300 of these since 1998. It uses the same transaxle as a 265-Horsepower Lincoln so the 200 horse V6 will never have enough power to harm it. Some vehicles need more cooling capacity which is fairly easy to do with a larger radiator.
Step 5) Handling and stability: This we divide into two areas, one is evasive manoeuver and cornering stability, the other is straight-line highway stability. For example if you tow a fifth wheel it feels very good running down the highway passing trucks, cross winds wonít bother it, they just feel good. Try and run a fifth through the slalom or try and run it quickly down a twisty road with a few frost heaves and all of sudden it does not feel so good anymore. The high centre of gravity, the high pivot point make if quickly become unstable.
When we do our testing the best handling combinations have four wheel independent suspension, Well matched tire & wheel combinations and a low centre of gravity. Instead of assuming how something will work, take it out on a track and measure slalom speed lane changes and then you will see what really performs.
Most full size trucks and SUVís have live axle rear suspensions sitting on leaf springs that are 44" apart fastened to frame rails that are only 38" apart. Even though the tire stance is 66" the suspension stance is only 44 inches wide. When you have independent suspension, the stance is projected out to the tire stance or 62" in the case of an Intrepid. Having a wider suspension stance keeps the vehicle much more firmly planted in aggressive manoeuvres. The other benefit of independent suspension is low unsprung weight. That big live axle weighs a lot and it has to move over every bump in the road when it is moving quickly up over a bump it has enough momentum that it does not move down right away so on a bumpy road the tires are not planted on the road nearly as consistently. As well with independent suspension you can actually have stiffer springs without making the ride feel harsh.
The Intrepid has a much lower centre of gravity than any truck or SUV. In all the hundreds of front drive sedans we have out there I have never had a customer roll a trailer. I have had a couple drive off the road to avoid things another was not paying attention and went into a corner too fast and lost control but they always have slid to a stop. It seems when people do similar things with a truck they almost always roll the combination and what is more interesting if you look at how the hitches are bent during the accident it is often the truck that rolls the trailer not the other way around. An Airstream will slide sideways on dry pavement and stay on its wheels a truck or SUV will not. When you can show me a formula one car with its centre of gravity 18" off the ground Iíll change my mind on this one.
On the Intrepid the tires are 8.5" wide on a 7" wide rim on many trucks you will find 10.5" wide tires on 6.5" wide rims. You want the tires to match the rim width for two reasons. One is that for straight line stability the tire does not sway. Walk up to the back of a new BMW STS or Benz and try and push the back of the car side to side, it wonít move and inch. Next find a truck with 265 tires on it and you will be able to move it a few inches side to side. In an emergency manoeuver the wider rim keeps the tread on the pavement where it will do you some good the narrow rim may be better for off road but in an emergency manoeuver it will not keep that big balloon truck tire flat on the pavement the rim just gets lost in all that rubber. Again this is not rocket science, look at any good road or sports car and you will see a rim that closely matches the tire width. Does it make sense that an 8600-GVWR truck should have a smaller wheel that a 5000-lb Intrepid?
Often people talk about wheelbase like it is the only thing that matters in towing and I must say when everything else is wrong it sure helps with straight line stability. It does not help in an emergency manoeuver as the vehicle has to be turned more aggressively to accomplish the same change in direction. Wheel base and overhang are pretty directly related if you donít believe this try towing a fifth wheel with the pin a foot behind the axle and anyone with a Pul-Rite can tell you what the effects of reducing overhang are. We measure overhang as a percentage of the wheel base and it gives us very accurate comparison, a vehicle with 120" wheel base and 40" of overhang will handle every bit as well as a vehicle with 150" wheel base and 50" of overhang if everything else is equal. If you like to get into State parks and tight campsites that long wheel base will cost you. I can park a 34' with the Intrepid in sites where you would not park a 28' with a long wheel base truck.
Certainly an Intrepid is much lighter than a 3/4 ton truck 4000 vs 6000-7000 lbs. The heavier weight does help with the straight line feel somewhat but it is almost detrimental in aggressive manoeuvres. If all that weight was down near the road where it could do you some good it would help more. On handling the other thing to think about is that you will likely drive your tow vehicle far more miles without the trailer than with it. As a solo vehicle there is no comparison in accident avoidance capability.
Please see the next post for step #6