On December 27 we joined a group of 4×4 geocachers for a caching run in the Dale mining district east of 29 Palms. This is a belated report on that trip—just after returning I came down with a serious cold that knocked me for a loop.
Desert mud
(About the mud. There was only one mud puddle, but it is a badge of honor for 4x4s to be covered in mud. I took this photo the next day. The mud originally completely covered the windshield and headlights.)
Now for a few details.
I think the number of vehicles was fine for a 4×4 run. The route was chosen well so that the turn-around points had enough room for all the vehicles to maneuver. Geocaching with that many vehicles, however, is problematic. With the caravan sometimes stretching out over a mile, those at the end of the line had no opportunity to hunt for a cache. By the time they arrived to park, the leaders had already found the cache, signed the log with the preprinted sticker, replaced the cache, and were ready to go again. On several caches, I never had an opportunity to even get out of the truck.
The route pushed the capabilities of the Ridgeline. On some of the rocky sections I repeatedly scraped the bottom. An after the run inspection revealed no visible damage, but still… It was disconcerting to hear those scraping noses from underneath. There were two or three sandy hills to climb, and despite airing the tires down it was a struggle. On one hill that had been chewed up pretty well by the time I tried, the Ridgeline bogged down three-quarters of the way up. I chose another route and made it—barely.
In retrospect, I could have done better. It’s a matter of understanding how the Ridgeline works (which I did theoretically, but not practically). The Ridgeline has 4-wheel independent suspension. It is primarily front-wheel drive, although when required, variable torque can be applied independently to each rear-wheel. Left and right-side clutches on the rear axle provide the desired torque to each rear wheel. All this is managed automatically by the Electronic Control Unit (ECU).
Likewise, wheel spin is controlled by the ECU. Using the Variable Torque Management (VTM), the drive-by-wire throttle, and the ABS brake system, the Vehicle Stability Assist system attempts to prevent wheel slippage (and does a darned good job of it—when we hit a sand pit at 70 mph on our way to Eureka Dunes in Death Valley the VSA kicked in and kept the track straight as an arrow). The problem is, the VSA is so good that in slippery conditions (like climbing a sand hill) the only way the ECU can control wheel spin is by throttling down, and it will do so until the engine stalls.
To counteract this, the VSA can be turned off by the the driver and the VTM can be locked in. So this should work, except for a safety feature which the driver can’t override. The Ridgeline also has a Tire Pressure Monitoring (TPM) system. Inside each tire is a wireless sensor that will alarm on the dash if the pressure drops below 25 psi. When the ECU detects this, it will not allow the VSA to be turned off.
Since I had aired down, I couldn’t disable the VSA and so couldn’t get full throttle performance when I was climbing the sand hills. A little research now tells me that there is an under-hood fuse that can be pulled which will disable the VSA (hmmm—maybe it also disables ABS). People who have run the Ridgeline in sand say it makes a world of difference.
The caching caravan
