Hi,

Has anyone successfully driven a 3G RDX with SH-AWD on a beach with soft sand?

This would be stock Advance tires with air let out, no modifications to the vehicle. Curious if SH-AWD behaves close enough to 4WD for driving in the sand, and also a little worried about the ground clearance.

Thanks!

 

I was thinking about this recently too, as I explored the option of getting a vehicle beach permit to get access to some of the less crowded areas in NY. I think it would perform well - the AWD system is very good (at least in the snow, where I put it to the test) and I don't see why it wouldn't do just fine in the sand. I think the ground clearance is probably fine - it's on par with any Subaru and only a inch or two less than "serious" off road vehicles.

 

Not my RDX but I just saw this...

RDX on Beach

Seems to be OK on the beach.

 

Over the years, I've been on the sand at various locations in NC with an older Honda that used the FWD+RW assist "Real Time" AWD. Since I stayed on the hard-packed areas, it was mostly like driving on a sand covered road.

BUT, everytime I've been on the sand, I've seen people stuck. The ingress/egress areas tend to get soft and this is usually where the tow trucks wait with well-used tow straps. People who drive in snowy climates probably due better since they tend to fully understand the importance of momentum and maintaining speed in low traction conditions. Sometimes I've had to get a running start to make it to the tarmac with sand scraping underneath for much of the exit dash.

Even though the SH-AWD system is magnitudes more sophisticated than on-demand systems, there's no substitute for common sense and/or proper tires. As long as you stay on the hard stuff you'd be fine. If you don't, SH-AWD probably won't matter much.

 

Hmmm. I had no trouble on sandy forest service roads around Santa Fe a couple months ago, but those were relatively hard compared to fluffy beach sand. The tires aren't very wide and the front differential is fully open except for whatever funkiness the brake-based traction control wants to do. And as wisely noted by DJA123, momentum is a terrible thing to waste when you don't want to stall out and dig in. So brakes aren't such a good thing compared to true locking differentials like you might find on a "serious off-road vehicle" ( which would also have wider tires and more ground clearance ).

Which is to say, if one of the front wheels starts to spin and dig itself into soft sand, your chassis will be on the sand in no time. There's really not very much ground clearance to spare before you will be trying to plow the beach with the front air dam.

Letting out some air to increase the contact patch of the tires is a good idea. Just make sure you have a pump to get them back up to spec before you hit the highway. And it's best to let out the air BEFORE you get stuck!

Might wanna take along a six pack in a cooler in case you need to make friends with someone in a "serious 4WD vehicle". And it's always good form to have your own tow strap if you're testing the limits. Instant cred, even if the car turns out to be a wus.

 

I hadn’t realized that the torque vectoring only applies to the rear wheels, not the front, but that does seem to be the case. Still the TV would help a lot in snow/sand conditions even if it’s just the rear, I would think.

l do remember in my old CRV that traction control was anathema to icy conditions, especially at low/no speed. I don’t know how the much more sophisticated system on the RDX handles things, but there’s still a button for turning VSA off.

Also, to clarify my earlier confidence, I absolutely think the RDX is less capable than some other SUVs. And even “serious” SUVs get stuck in the sand, mostly because of driver over confidence (“I have a Wrangler so of course I can drive anywhere!”) and the Internet is full of videos of Jeeps getting towed out just before the tide comes in... or not getting towed out in time. Don’t be that guy. Be cautious, have the right equipment (shovel, traction mats,etc) and know the tides.

 

I don't think overdriven torque vectoring per se will help at low speeds in low traction conditions, but the limited slip capability that's part of the package is definitely a plus. "Torque vectoring" is now a massively overused and under-understood term, throughout the industry, and it's usually used to mean "limited slip".

The early version of the higher end Honda/Acura AWD rear diff, the VTM-4 diff, has a locking function that can be used at low speeds ( rear diff only ), and that's very helpful. That's one of the reasons I still have a 2005 MDX in my fleet.

But AFAIK no-one has a limited slip or locking front diff for a transverse transaxle ( FWD based ) AWD setup. You need a center differential and independent front and rear diffs to make it work, and that goes along with a longitudinal engine and transmission.

But not every vehicle with a center diff longitudinal AWD/4WD has true limited slip or locking front and/or rear differentials. Many ( most? ) now use brake-based traction control, for cost and weight savings, and efficiency. And it's not the same, especially for low-traction conditions.

 

When you get older ( like me), you won't even think of doing something like this.

I did drive a company car on the beach in Florida once. Probably coated the undercarriage with sand and salt.

 

You mean liking driving on any northern road in winter?

But full immersion in an ocean, or being dragged through sand dunes by a tow truck, not so much.

 

I drove my SH-AWD RDX in SNOW mode on very deep sand in Florida. It went over deep sand with ease, even uphill. Later, on another beach three cars got stuck on shallow sand. One of them was Mercedes sedan with rear wheel drive (empty trunk), second was VW Beetle and the third one was rear wheel drive truck. I just couldn't believe that truck with big tires can get stuck in shallow sand, but it did (no load over rear wheels). Whole bunch of people couldn't push them out until a guy with 4-wheel drive truck helped them.

Many AWD SUVs drive rear wheels only when front wheels slip. RDX drives them all the time with torque proportional to load over axle - heavier front gets a little more. It can move up to 70% of torque to one or both rear wheels, because they are driven 3% faster than front wheels and each of them has separate clutch.

 

Taking these vehicles into soft sand created an unsurprising outcome. I imagine many warm climate drivers -- who have never driven in low traction situations -- don't understand how this can happen.

Yeah, the SH-AWD is very impressive engineering; gobs beyond on-demand systems. I use the SH-AWD mode in the MID display as my default just to watch the competence of the system. I can see why they give us the option to watch the show.

 

I'm amazed at how the car handles and corners in heavy rain. I haven't gotten it to under-steer yet. But I'm not gonna try TOO hard.

I don't know about snow because we haven't had any. I haven't picked up a snow shovel in two years. By the time I ever get the car out in 6-10' of snow, my Continentals will probably be half shot and it won't be a fair test.

To take it on the beach, I'd need a permit here. I've done it briefly with my '03 Pilot and it was no problem, even without airing down. But I didn't like the salt and sand in everything. I just wouldn't do it with my RDX. I don't want to be the source of entertainment for the other 4-wheelers.

 

In 6 to 10 feet of snow, the tires aren't gonna be the only problem.

In 6 to 10 inches of snow, it depends on whether the snow is light and fluffy or wet and slushy. Dense wet snow is a challenge, even with appropriate winter tires, because of the limited ground clearance. When you start floating the chassis on the snow, you lift the weight off the tires and lose traction. Directional control is pretty good, but it gets hard to maintain momentum. Turning off VSA can help at low speed, because it allows the tires to claw ahead more. Not all wheel spin is bad.

On sand, it could be just the opposite. Moist compacted sand may be fine, but dry powdery sand may offer little traction and allow the tires to sink.