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Old 10-12-2003, 08:44 PM   #11
RockyMtnRay
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Default Re:Gonna replace my Cherokee with a Tundra

Mike Laupp wrote:
Quote:
I don't understand the short wheelbase stability problem. I always thought that the tow vehicle wheelbase should be short in comparison to the trailer. I have never liked to back a short trailer with a long wheelbase TV. I would think that you would want a short wheelbase for twisty roads.
It's basically a leverage arm issue when it comes to stability, particularly in two situations: sway and steep descents on hairpin turns (where the trailer tends to cause the TV to oversteer and could go all the way to a jackknife). In either situation you're trying to prevent the trailer from pivoting the TV around it's rear axle.

The rear overhang (distance between the TV's rear axle and hitch ball) is the leverage arm the trailer can act on to push the TV around. The wheelbase is the length of the leverage arm you can control to counteract the trailer's leverage arm. The larger your leverage arm is relative to the trailer's leverage arm, the more control and stability you will have. A 5th Wheel trailer, because it connects to the TV right over the rear axle has a zero length leverage arm and therefore is almost totally sway proof. Most tow vehicles have fairly similar rear overhangs (3 to 5 feet) but wheel base varies tremendously.

As for backing, you're right. The longer the TV wheelbase is, the harder it is to jockey the TV around to push the trailer where you want it. And I am indeed going to have to deal with this since my street is fairly narrow in front of my driveway and the turn is a sharp right angle into a 18 foot wide driveway. With the Jeep, this wasn't a particularly difficult backing maneuver; with the substantially longer Tundra, it's going to be a bit of a challenge.

As for twisty roads (not involving descents), it's a mixed bag. Yes, a shorter TV wheel base means a more maneuverable TV. However, the trailer still wants to go straight and thus it will tend to cause the TV to understeer on level or ascending turns. So again, if your (the driver's) leverage arm is longer relative to the trailer's leverage arm, the TV will have less tendency to understeer. In my experience, the understeer issue is more important than how maneuverable the TV is.

Did I clarify things?
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Old 10-12-2003, 09:06 PM   #12
RockyMtnRay
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Default Re:Gonna replace my Cherokee with a Tundra

kdbell wrote:
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We are interested in your TV thoughts. My wife and I are just in the market for a TM (2027SL, 3023, or 3124KS) and I am collecting various owners thoughts about various TVs. I want to have adequate power to negotiate reasonable grades (6-8%) safely since we live in Virginia and camp in Western NC, VA, and WVA, but I don't want to over buy the TV and end up with one that is too thirsty to afford to feed when I'm not towing. By the way, what model TM do you have?
I am towing a 2720SL. Important difference between my situation and yours: I not only have the 6 to 8% grades (or more) but I also am encountering them at fairly high altitudes (often well above 10,000 feet). A normally aspirated engine (i.e. one that doesn't have a supercharger/turbocharger) only has about 50% of its rated horsepower at those elevations because of the thinness of the the atmosphere. So I&'m going to have to start with about twice as much rated power to still have bearable performance as you would.

All that being said, I would suggest you not go much below a 4.0 liter engine with around 200 hp or so. You can get away with good V6 (or other 6 cylinder). Or putting it another way, don't buy any TV that has less than a 5000 lb tow rating. From all my studies, the goal is to keep your trailer's weight below 80% of the the TV's rating...or about 4000 lbs. And a loaded 3023 is going to be pretty close to 4000 lbs.

An important, but often overlooked issue (especially if mountain towing will be common) is the axle ratio of the TV. Optimum for mountain towing is around 3.9 to 4.1...but those ratios produce notably higher engine RPM in daily driving and nick the gas mileage by 10 to 20 percent over the more common 3.07 to 3.5 ratios. Another important consideration is making sure the TV has the factory tow package (or all of its components)....specifically heavy duty engine coolant parts (radiator, radiator fans, etc.) and particularly a heavy duty transmission cooler. Towing really heats up automatic transmissions and if they're not properly cooled, they will fry and then die in just a few thousand miles.
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Old 10-12-2003, 09:29 PM   #13
RockyMtnRay
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Default Re:Gonna replace my Cherokee with a Tundra

efelker wrote:
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One internet service is a little different than most. In this case they use a handful of dealers where you go to pick it up. Take a look at www.carmax.com . Thsy do have Tundras.

Closest to you is Milwaukee & Chicago. From what I can see, their prices are about 2 to 3K under MSRP and about $400 - $800 under invoice. If that's too far to go to pickup, what you might do is use their quote to get you a good local price. It's the old, "Can you better this deal?" approach.
Ed...

Yeah I looked into Carmax but there are two problems with Chicago/Milwaukee dealers. First is the distance...based on what my business partner experienced, I should be able to do almost as well with a dealer somewhere on the Colo Front Range (i.e. within 70 miles) using one of the other services (particularly Carsdirect)...and won't have the cost and hassles of making 2500 mile roundtrip (an unbelieveably boring one too, I might add). The other problem is that all of these services work off of dealer inventory...and midwest dealers are very unlikely to have in stock a Tundra equipped for Colorado: 4X4, Toyota Racing Development (TRD) Off Road suspension package, skid plates, 3.91 limited slip differential, etc.....and are less likely to have any with the Towing Package. Almost all the Tundras sold here have all of these packages and options.

Now what Carmax does have that the others don't is below invoice pricing. Only extremely high volume dealers can afford to dip down into this "manufacturer holdback" zone...and sell vehicles with only a couple of hundred net profit. If I can do as my biz partner did and get one at the Carsdirect price, I'll be paying right about invoice cost. If I do direct negotiations, I'll probably be lucky to get within $1K of invoice (though still $2K below MSRP). I put in a request for bid from Carsdirect.com this morning; hopefully I'll hear from them sometime tomorrow.
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Old 10-13-2003, 07:31 AM   #14
CC_Turtle
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Default Re:Gonna replace my Cherokee with a Tundra

We currently pull a 2027sl with a 6cyl toyota tacoma.. the tacoma has 190 hp.. i have been thinking about adding a supercharger for more hp and more torque.. has anyone done that or have any thoughts on that? the supercharger would add about 70 hp and more torque (can't remember the amount) thanks!
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Old 10-13-2003, 08:04 AM   #15
mjlaupp
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Default Re:Gonna replace my Cherokee with a Tundra

[quote author=RockyMtnRay link=board=20;threadid=1436;start=msg10106#msg1010 6 date=1066014411]
I am towing a 2720SL. Important difference between my situation and yours: I not only have the 6 to 8% grades (or more) but I also am encountering them at fairly high altitudes (often well above 10,000 feet). A normally aspirated engine (i.e. one that doesn't have a supercharger/turbocharger) only has about 50% of its rated horsepower at those elevations because of the thinness of the the atmosphere. So I'm going to have to start with about twice as much rated power to still have bearable performance as you would.
[/quote]
Ray,
You might want to consider the Gear Vendors Under/Overdrive as an answer to the power problem.
www.gearvendors.com
MJL
p.s. Thanks for the info on TV wheelbase.
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Old 10-13-2003, 09:20 AM   #16
RockyMtnRay
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Default Re:Gonna replace my Cherokee with a Tundra

Quote:
You might want to consider the Gear Vendors Under/Overdrive as an answer to the power problem.
Interesting, thanks for the link. I'm impressed....these guys actually understand the issues involved in modifying a 4X4 drivetrain...such as increased angle of the rear driveshaft (reduces reliability of rear U-joints, introduces vibration), lengthened front driveshaft (more vibration at higher speeds), and reduction of ground clearance in the center of the vehicle. Unfortunately they only make kits for the Ford/Chevy/Dodge full size 4X4 trucks...nothing for Tundra.

And in any case, it's probably not going to be necessary...most of the steeper climbs in the Rockies (those over 6%) are usually only 5 to 8 miles in length and often have low speed limits (35 to 45 mph). I'm confident the Tundra V8 has enough horsepower, torque, and engine/tranny cooling capacity to handle my TM on these grades considering that my TM's weight is just over half of it's rated towing capacity. Actually my Jeep, with it's 4.0 L I-6, could have handled these climbs if it had the heavy duty radiator and 4.10 gears instead of the 3.07 gears.

OTOH, if I had a Ram 4X4 with a Cummins TD...and was trying to haul a 14,000 lb 5th wheel up these grades, you bet I'd be in line to buy one of these over/under kits.

Quote:
p.s. Thanks for the info on TV wheelbase.
Most welcome. Being a sports-car fan...I drove a 240Z for 10 years...I'm pretty acutely sensitive to understeer and oversteer issues on mountain roads. Before I sorted out the WDH issues on my Jeep/TM combo, I was running with lighter-than-unhitched weight on the Jeep's front tires...which amplified any tendancy toward under- and over-steer. As I noted at the beginning of the thread, I never experienced any loss of control due to trailer-induced oversteer in tight, steeply descending turns but I had a sense (mostly from the "scrubbing" sound of the tread) that the front tires were definitely fighting substantial oversteer forces. And that was on just an 8% grade. Trailer induced oversteer (especially on descending turns) can become very nasty very fast because it's self-amplifying.
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Old 10-13-2003, 11:38 AM   #17
mjlaupp
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Default Re:Gonna replace my Cherokee with a Tundra

Ray,
I ran into some oversteer problems with my F150 / 2720SL combination. Read: short wheelbase - standard cab - short bed, the same as an Explorer. Most of the incidents occured at moderate speeds in turns with a decreasing radius. At a given point the truck would dive to the inside of the turn. I was always able to correct for the oversteer and eventually learned which seemingly innocent curves to watch out for. After replacing the shocks and adjusting the WDH I managed to minimize the number of excursions. I was going to add heavy duty anti-sway-bars to the truck when I finally realized the source of the problem. The truck was factory equiped with P series passenger tires (for ride comfort). The relatively thin passenger car radial sidewall construction was letting the tread roll under in the turns. My next step was to replace the truck tires with ones that were LT rated before the next RV year.
I ended up replacing the tires along with the truck. Probably won't be able to check out the performance in the Ozarks until next spring.
MJL
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Old 10-13-2003, 01:03 PM   #18
RockyMtnRay
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Default Re:Gonna replace my Cherokee with a Tundra

Quote:
I was going to add heavy duty anti-sway-bars to the truck when I finally realized the source of the problem. The truck was factory equiped with P series passenger tires (for ride comfort). The relatively thin passenger car radial sidewall construction was letting the tread roll under in the turns. My next step was to replace the truck tires with ones that were LT rated before the next RV year.
Mike...

Yep, you nailed it. Now that you mention it, having high quality Goodyear Wrangler LT tires on my Jeep is probably what's been saving my skinny butt so far. I'm really glad you mentioned this issue with the P-Series tires...Toyota (like all the other manufacturers) is equipping the Tundra with P-Series tires for better ride quality.

I think one of the first things I'll do after I get this vehicle is head over to a tire store and get the best deal I can on a swap for good Goodyear Wrangler LT tires. It'll probably cost me around $150 to $200 per tire but it'll be worth it for safety (and off road traction). I'll gladly trade a bit of ride comfort for the strength and stability of real truck tires.

Quote:
I ended up replacing the tires along with the truck.
Well, that's one way to get new tires. I assume you're enjoying the new F250.
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Old 10-13-2003, 03:04 PM   #19
mjlaupp
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Default Re:Gonna replace my Cherokee with a Tundra

[quote author=RockyMtnRay link=board=20;threadid=1436;start=msg10115#msg1011 5 date=1066071830]
Well, that's one way to get new tires. I assume you're enjoying the new F250. [/quote]
Oh yesssss! More room, quieter, better ride, more features and more power ;D
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Old 10-13-2003, 08:15 PM   #20
kdbell
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Default Re:Gonna replace my Cherokee with a Tundra

Ray,
Many thanks for your great information on towing a 2720SL at high altitude. While we are quite familiar with the towing requirements for a pop-up, your information was extremely helpful to our decision process for finding a tow vehicle.
thanks again and happy towing.
D&K
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