Towing Advice for Colorado

OK, I've really enjoyed this site and I've learned a ton! We've had our '98 2619 for a little over a year and have done a number of short trips here in the Midwest (Missouri) and a 2000 mile trip to Florida. We tow with a 2000 Mitsubishi Montero Sport, V-6, 5000# capacity, WD-hitch and we travel at about 3300 in the trailer, a 4-pack and all the misc. stuff you need for comfort. It's done fine on the gentle hills and flat lands we've used it on we get a respectable 17mpg and we absolutely love our Trailmanor! We're thinking of a week in Colorado next summer (mid-August) and would love some thoughts on 1. is it possible given my rigs limits 2. what modifications would be necessary to make it safe? 3. are there any routes that might be easier than others (coming in on I-70) and thinking about going through Denver, in and around the Aspen area and then down to Royal Gorge out to Col. Springs and then back home? Thanks.

Tim
I Live in Denver by the Morrison exit which starts the climb up I-70. There are Three 6% grades going westbound to Aspen, and a 7% grade eastbound at the Eisenhower tunnel.

The first is from the Morrison exit to Genesse exit. The second is getting to the Eisenhower tunnel and the 3rd is Loveland pass.
I have a 1999 4-runner 6 cyl towing a 3124KS. These steep grades will slow me down to 35mph in some places. You will be in good company with all the 18 wheelers.
Be sure to take your truck out of overdrive... all the way up.

A good place to stay is the Aspen/Basalt campground..full hookups ..
http://www.coloradodirectory.com/aspenbasaltcamp/

[RockyMtnRay]

Originally Posted by Tim2619

OK, I've really enjoyed this site and I've learned a ton! We've had our '98 2619 for a little over a year and have done a number of short trips here in the Midwest (Missouri) and a 2000 mile trip to Florida. We tow with a 2000 Mitsubishi Montero Sport, V-6, 5000# capacity, WD-hitch and we travel at about 3300 in the trailer, a 4-pack and all the misc. stuff you need for comfort. It's done fine on the gentle hills and flat lands we've used it on we get a respectable 17mpg and we absolutely love our Trailmanor! We're thinking of a week in Colorado next summer (mid-August) and would love some thoughts on

Answers to your questions...

1. is it possible given my rigs limits

Yes, though as noted above with only about 220 ft-lbs of torque you will be down to to around 30 to 35 mph for extended periods with the engine revving very high in 1st or 2nd gear. Most of the 5 to 6 percent grades going west on I70 are 5 to 7 miles in length...and the upper one on the east side of the Eisenhower tunnel has a 55 mph left lane minimum speed for about 12 miles. That means you will be in the right lane crawling behind the Semis at 25 to 30 mph the whole way. Also keep in mind that you will climb 6000 feet coming out of Denver to reach the entrance to the Tunnels. Going eastbound there are two very challenging 7% grades on I70 that are respectively 10 miles in length (Vail Pass) and 8 miles in length (western approach to the Eisenhower Tunnel). Because of its seemingly unending length, steepness, and altitude the western approach (going eastbound) to Vail Pass has garnered a lot of unhappy comment and infamy on the various towing forums at RV.NET.

One thing you can do to make the mountain crossings much less traumatic is to do them as early as possible in in the morning when the air temperature is much lower. Cooler air is much denser so your engine will make substantially more power and your vehicle will be much less likely to experience an overheated cooling system or overheated transmission. Because the air here is very thin and dry, Colorado has very large diurnal (night/day) temperature swings...often as much as 40 to 50 degrees. In the mountains the temperature at dawn (even in August) will be around 35 to 40 degrees; by noon it will be around 70 to 75 degrees. I seldomly have seen disabled cars/trucks/motorhomes along the roadside during early morning crossings of the Divide but, by afternoon, the roadsides on both sides of the high crossings (like the Eisenhower tunnels) have numerous vehicles that have become disabled due to overheating.

One thing that's mandatory on the descents is to put the transmission in a lower gear (2nd gear on most automatics) before starting the descent. If you try to hold your speed down with only the brakes, you are guaranteed to have overheated and fading brakes long before the bottom. The saying hereabouts is that overheated brakes will kill you!

2. what modifications would be necessary to make it safe?

A very high quality brake controller like the Tekonsha Prodigy that provides proportional braking regardless of road grade. Regular pendulum based "inertial" controllers over brake on descents. And "time-delay" controllers are a disaster waiting to happen.

If your Montero has an automatic transmission and doesn't have an external transmission cooler, it's absolutely mandatory that you have one installed. The extended (20 to 30 minute) periods of high RPM, low gear operations that you're facing will create enormous amounts of heat in an automatic transmission...if you don't have a good external cooler, you are guaranteed to cook/kill the transmission.

If you have ever experienced higher than normal engine coolant temperatures while towing, you should investigate having your radiator replaced with a heavy duty model. Mountain towing (especially in the afternoon and at low speed) places a huge demand on the engine cooling system.

Have all driveline lubricants replaced (ideally with synthetics) before trying this trip...specifically engine oil (recommend Mobil1), transmission fluid, and differential fluid (at least the rear). All components will be enduring very high temperatures and high quality lubricants are needed...synthetics are better because they're less likely to break down at high temperatures.

3. are there any routes that might be easier than others (coming in on I-70) and thinking about going through Denver, in and around the Aspen area and then down to Royal Gorge out to Col. Springs and then back home?

Going west, no...the 5 to 6 percent grades on I70 are less steep than any other route.

However, going east from Aspen, I strongly recommend you leave I70 onto US24 towards Leadville at the Minturn exit (about 5 miles west of Vail). This will take you across the Continental Divide into the upper Arkansas River valley via Tennessee Pass and let you avoid both very challenging eastbound climbs on I70 (Vail Pass and the western approach to the Eisenhower Tunnels). US24 has a steep (~7% grade) though quite short initial section over Battle Mountain Pass but from then on the grades are quite gentle and Tennessee Pass itself is hardly noticeable. Tennessee Pass was the "water route" that the Union Pacifc railroad used for its main line across the Continental Divide and railroad grades seldomly exceed 3%. Just continue to follow the Arkansas river valley downstream via US 24, US 285, and US50 to reach the Royal Gorge. This is not only an "easy" route but it's also highly scenic as there are about a dozen "14ers" (14,000 feet or higher mountains) lining the west side of the Arkansas valley.

Don't even think about going east out of Aspen via Colorado 82 over Independence Pass. This road has numerous narrow spots (total road width of about 12 feet for both lanes) and a length restriction of 35 feet...it's very much not recommended for trailers. There are also several miles of very steep grades (over 8%) on both sides with hairpin curves. And it's very high...about 12,100 feet above sea level. Mid summer blizzards and icy road conditions...even in August...are a distinct possibility.

HTH

Thanks all....I was thinking in that direction regarding the synthetics and the tranny cooler. Also, when towing up and down these steep grades is it preferrable to use 4WD? Thanks again...

[RockyMtnRay]

Originally Posted by Tim2619

Also, when towing up and down these steep grades is it preferrable to use 4WD?

NO! Absolutely not! You don't/won't need it, it could destroy your drivetrain, and it puts even more load on your engine.

First, grades in the 5% to 7% range are not at all steep from a traction point of view...a 7% grade is only 1 feet of rise in 14 feet of road; a 5% grade is only 1 feet of rise in 20 feet of road. Your rear tires (especially when loaded down with several hundred lbs of cargo and tongue weight) have more than enough traction to easily move your rig even on wet pavement and way more than enough traction on dry pavement. Only if the road surface was very icy, muddy, or snow packed would you have any traction problems on 7% grades...and icy/snow pack conditions, while not unheard of at 11,000 feet during a summer storm (even in August ), are pretty rare and would last only an hour or two at the most. (Storm avoidance, BTW, is yet another reason for early morning travel...95% of Colorado's summer storms are of the afternoon thunderstorm variety.)

Second, unless your Montrero has "full time 4WD" or "All Wheel Drive", using 4WD on dry or even wet pavement is a sure recipe for destroying your driveline. The problem is that regular (part time 4WD) has a transfer case that causes the front and rear driveshafts to turn at the same RPM. However on every turn, however slight, the front and rear tires make different arcs and therefore have slightly different RPMs. Because the strain that builds up between front and back can only be relieved by tire slippage...which is minimal on high friction surfaces...huge stress builds up in the front and rear differentials as well as in the transfer case. The usual result is destroyed front differential spider gears.

Third, engaging 4WD adds a substantial (around 5% to 10%) parasitic drivetrain power loss. The very last thing you need when your engine is working hard is to add even more parasitic loads. (As a side note, I recommend you plan on turning off your air conditioning when you start these climbs...the AC adds a parasitic load to the engine and dumps heat in front of the radiator, both of which are very bad).

With 4 wheel brakes on the Montero and brakes on the trailer, you certainly don't need 4WD for a descent. But you must use the engine braking (through the rear wheels) to save the wheel brakes from overheating on descents.

Your major challenge is not at all a lack of traction but rather a lack of power (compounded by the altitudes) combined with a need to overcome gravity as well as the usual rolling resistance/aerodynamic drag. At 6000 feet (e.g. the west side of Denver), your engine will have only 80% of the power you're used to having; at 11,000 feet (e.g the altitude of most Colorado passes as well as the Eisenhower Tunnel entrances), your engine will have only 60% of the power you're used to. IOW, you will have lost a whopping 40% of your engine's power just when you need it most for the steepest grades.

If you want to simulate this, completely remove 2 or 3 of your engine's spark plugs and try to tow your trailer up the steepest grade you can find in the Ozark Mountains. You'll find that it can be done...but the highest speed you can reach is about 35 mph and to achieve even that your throttle pedal will be on the floor (your right leg will get very tired) and the engine will be revving at 4500 RPM (or higher) in 1st or 2nd gear the entire time.

With suitable preparations (e.g. transmission cooler and high quality lubricants), your vehicle's drivetrain will readily survive this abuse and you'll be able tolerate the slow speeds and unaccustomed engine noise on a one-time trip. Those of us who regularly do this kind of towing usually do as I did and upgrade to a tow vehicle with a high power V8 and low (high numerical) axle gearing.

once again, thanks....your info is really helpful. Can't wait to experience CO for myself. Tim

[fcatwo]

We have a friend here in our Texas RV park who used to crank his cam-type Reese WDH down so tight (to make sure the anti-sway feature worked) that his rear wheels would sometimes spin starting off on hills. His 4WD would bail him out but he finally decided a little more weight on the rear might prevent the horn blowing he would hear while getting into 4WD. Must have worked because he hasn't mentioned the problem in a couple of years. The few bucks it costs to weigh our axles when loaded is IMO some of the best money we can spend on our RV hobby.

Thanks so much for all the great infomation. I'm new to the forum and wanted to thank all for the helpful advise. I was really concerned about using our Montero for a tow vehicle but followed everyone's advice and took the pludge. I love our new Trailmanor and our Montero pulls it beautifully. Thanks, Guys!

A sidebar to this: Since I live and work in the upper Arkansas River valley, I totally agree with RockyMountainRay's route recommendations. If you make your trip as planned and come through Buena Vista, stop by the Flyfishing shop that's on Hwy 24 across from City Market and look me up. It'd be great to meet up with you! I'll give you the inside scoop on area's best stuff. Ask for Carol. (Invitation also open to any TM'er coming thru the Salida or Buena Vista, CO area April 1-mid Sept.)

-Fishcat
Colorado Flyfisher (with ArkAnglers Flyshops and Guide Service)