What is your ground clearance with your hitch

[p220sigman]

I added the Airlift 1000 with onboard compressor to resolve the low clearance issue with our 4 bike rack. It doesn't raise the rear when unloaded that I can tell, but it resolved the scraping issues. We have since added a pop-up camper and I've found it to be helpful there as well. We don't get much front rise with the camper attached, so I have just run the bags with no weight distrubution up to this point. We do scrape occasionally with the camper, but that may also be because the drawbar has a part that sticks down a little below the bottom of the receiver. Overall, we have been very happy with the system. I keep about 5-10 PSI when empty and 30 when loaded.

[brian_bp]

Our 06 Sienna has a Class III hitch with 2" receiver from U-haul. It scrapes periodically even when the van is unloaded when going up moderately sloped driveways etc.

U-Haul sells multiple brands - it could be one of at least three different designs.

After more than 7 years, I still have no problem with the receiver scraping; mine is the OEM unit, and while the 1.25" box opening helps (allowing 3/4" more clearance), there are other design features which help as well.

We haven't dared to load it with the boat yet, and are worrying about the hitch clearance when loaded, as the rear suspension seems rather soft and easy to bottom out when loaded (not to mention its too low for my liking unloaded!). It already drops quite low when loaded with 4-5 people and 2 bikes on a bike rack....

Bikes on a rack stick out rearward and thus have much more of an effect on rear axle load (and thus rear ride height) than you might think.

We are thinking of getting some slightly longer/taller/stiffer rear springs to lift the rear end up; do those exist and can be easily fitted? Do AWD models use higher or stiffer springs to get better clearance?

Taller and stiffer springs will be too tall and stiff when not hauling or towing, although in the rear they would be easy to install. Yes, the AWD uses a slightly taller spring... at both front and rear; if only the rears were changed, the empty van would be tilted forward.

How good is the air-lift system, does it raise the van's rear higher even when unloaded?

The air bags (Air Lift or Coil-Rite) work well. They are not intended to raise the height beyond stock, only to maintain near stock height despite added load. They have no effect when only minimally inflated, which is the biggest advantage of air suspension.

Lastly, would it be worth investing in a new set of 17" wheels to upgrade the 16" (CE model) to get better ground clearance?

No. As with most vehicles, all of the factory-available wheel and tire combinations have about the same overall diameter. The 17" wheels are obviously 1" larger in diameter than the base size, but the tire sidewalls are about 1/2" shorter (60% of 225 mm instead of 65% of 215 mm), so the net effect is about the same overall diameter for the same gearing and clearance.

[speedkar9]

After more than 7 years, I still have no problem with the receiver scraping; mine is the OEM unit, and while the 1.25" box opening helps (allowing 3/4" more clearance), there are other design features which help as well.

You've got the LE with larger wheels? A smaller hitch and larger wheels may yield more ground clearance than my setup.

In my opinion the 2nd gen Sienna's stock rear-end is too low, for my liking at least. (We've had a Previa :P )

Do you think I could get stiffer/taller springs to lift it up by say 1.5-2"? I want it to be higher than OE when unloaded - it would look much better to me. I've called around local shops and all they can offer is the silly air bag that replaces the spring - which I don't really like the idea of.

An Airlift 1000 would work only when the vehicle is loaded- I still scrape when unloaded.

My clearance is ~7.5" which is a tad smaller than the ~8" people have posted here.

Here's what the rear looks like right now on my driveway:



Here is the hitch- as you can see its battered up by the scrapes and hits its got in the past 3 months:



Here is the underside:



Here is the 7.5" of clearance I have. The vehicle is unloaded at the time of taking these pics:

[brian_bp]

I've called around local shops and all they can offer is the silly air bag that replaces the spring - which I don't really like the idea of.

The air bag (Air Lift or Coil-Rite) does not replace the spring, it is added inside the coil.

Here is the underside:

There's the problem: it isn't the Curt or OEM designs, which bend the crossmember forward to provide better clearance at the end plates. Although the tape measure shows clearance at the receiver box, that doesn't seem to be the problem. The corners are often more of a clearance problem, because the worst interference situation occurs at the corners when traversing a diagonal dip.

Personally, I would change receivers before messing up the suspension.

[p220sigman]

You might check to see if you have an upfitter for handicap conversions in your area. I think they swap out the rear springs judging by one that I see around here. The rear sits much higher than stock.

[07sienheaven]

I originally had a S Quality class 3 frame mounted hitch before and I got so tired of the van scraping. Even with my airlift 1000 at 25psi unloaded and unloaded, I would scrape a lot on any driveway incline. So I returned my hitch and got my money back, and paid to get a welded on class 2 hitch in my van. I actually have about the same ground as the bumper because the hitch is welded along the rear cargo floor and reinforced at the front and back. Its definitely a much different design, but it is strong (strong enough to recover a 6500 lb truck) and more importantly, no more scraping

[brian_bp]

... paid to get a welded on class 2 hitch in my van. I actually have about the same ground as the bumper because the hitch is welded along the rear cargo floor and reinforced at the front and back. Its definitely a much different design, but it is strong (strong enough to recover a 6500 lb truck) and more importantly, no more scraping

I won't challenge the validity of a design that I have not even seen, but the idea of welding a hitch onto a modern vehicle is scary... especially when that vehicle has a very sound set of integral hitch mounting points designed into the structure.

Horizontal and vertical forces are very different design challenges for the structure, so the ability to tow three tons with a rope (or cable or chain or strap) does not necessarily imply that the hitch is capable of safely carrying even 5% of that as hitch weight.

Can we see some photos? Maybe a separate topic would be good, since a custom hitch receiver is a notable subject by itself, aside from the ground clearance question.

[07sienheaven]

... paid to get a welded on class 2 hitch in my van. I actually have about the same ground as the bumper because the hitch is welded along the rear cargo floor and reinforced at the front and back. Its definitely a much different design, but it is strong (strong enough to recover a 6500 lb truck) and more importantly, no more scraping

I won't challenge the validity of a design that I have not even seen, but the idea of welding a hitch onto a modern vehicle is scary... especially when that vehicle has a very sound set of integral hitch mounting points designed into the structure.

Horizontal and vertical forces are very different design challenges for the structure, so the ability to tow three tons with a rope (or cable or chain or strap) does not necessarily imply that the hitch is capable of safely carrying even 5% of that as hitch weight.

Can we see some photos? Maybe a separate topic would be good, since a custom hitch receiver is a notable subject by itself, aside from the ground clearance question.

I absolutely agree with you, and I am/was just as skeptical about the idea as the next guy. My confidence in the hitch design continues to increase each time I tow with our van. I have logged about 2 hours so far towing 2500 lbs. with this hitch and I also have the lifetime warranty from the local shop themself. We here are some pictures for reference...

[fibber2]

Isn't that an interesting arrangement! I see that it is tied into the subframe just behind the rear axle. What provides side-to-side bracing at the bumper region?

[07sienheaven]

The hitch is welded to a 3/8 in plate that is then bolted to the rear sidewall of the cargo "tub" just in front of the rear bumper. Yea I agree, it is an interesting design and only time and use will yell how good of a design it is. Like I've said, I have towed with it and also used the hitch for my bike rack and I have had no flexing issues. The hitch is also backed by a lifetime warranty, so that helps a little. My last hitch was definitely strong and seemed very capable as I even pulled 5000 lbs with it for a short trip. Interestingly, although I bolted the old hitch to the weld nuts according to spec, when I took the hitch off, I could tell the bolts were already loosened a bit, scary. So I think any hitch design has its pluses and drawbaks. With a bolt on hitch, as is common, some drawbacks may be the bolts possibly coming off, the weld nuts failing, torsional bending and cracking, etc. For a welded on unit, there may be strength issues, failed weld spots, etc. If you think about it, all hitches on a sienna rely on a welded on component, for a bolt on, you are relying on six 3/4 inch weld nuts that are supposed to even ly distribute the weight of the trailer resistance and tongue mass. With a welded on unit, the weight is evenly distributed along all the weld points and the frame its welded on too. Remember, the Sienna is a passenger vehicle before it is a tow vehicle, it is a unitbody framed vehicle. I doubt that the "frame" section in which the weld nuts are located is dramatically thicker or stiffer that the of the other areas of the unitbody. That "frame" section on the van is still supposed to crumple as a crash absorber, so it should not be likened to a pickup truck frame. Although, with all that in mind, I would still say, our Siennas are more trucklike and capable than most people give credit to. It definitely tows much better in all respects than my old Nissan V6 pickup that had a 5000# tow rating.

[brian_bp]

Thanks for the photos!

I see that it is tied into the subframe just behind the rear axle.

The Sienna doesn't have a rear subframe; this hitch is welded to a structural point which is designated for jacking up the rear of the vehicle, so it certainly is strong (and in the right vertical orientation) ... although I don't know if the hitch tube is stiff enough for this purpose, or if continued cyclic loads for hours at a time are a concern (compared to brief and occasional nearly constant loads of supporting the rear of the vehicle on a jack).

The hitch is welded to a 3/8 in plate that is then bolted to the rear sidewall of the cargo "tub" just in front of the rear bumper.

So the entire vertical load of the rear hitch mount - which is substantially more than the load on the ball - is pulling down on the floor at this point. Would I put a concentrated 500 lb load against the back of the cargo/seat well? I'm not sure, but I do see the logic of the design.

The bolting in of the plate avoids metallurgical issues with welding, but is an invitation for tearing. I hope it has several well-fitted bolts.

The longitudinal (horizontal rearward/forward) loads are very unlike what the structure was designed to handle at those mounting points, and would certainly be better handled at the "frame rails". I'm undecided whether or not I am concerned about this.

[brian_bp]

That "frame" section on the van is still supposed to crumple as a crash absorber, so it should not be likened to a pickup truck frame.

I believe that the hitch attachment points are forward of the planned crush sections.

[fibber2]

The Sienna doesn't have a rear subframe; this hitch is welded to a structural point which is designated for jacking up the rear of the vehicle...

Sorry if referring to it as a subframe bothered you. More correctly it is identified as Rear Floor #4 CrossMember Assembly with Jacking Point. Net is secondary to the side rails themselves, this is one of the more structural sites in the rear of the vehicle, and a good starting point for an alternate hitch mount design. Still, I do share Brian's reservations about using the Body Lower Back Outer Panel and the Rear Floor Pan & braces for the rest of the mounting.

For safety's sake, I would do a regular inspection of the welds for signs of deterioration. Painting might also be a wise idea to reduce corrosion.

[07sienheaven]

hey guys, just want to give an update on this special hitch design I have. 400 miles of towing with amongst our 2500lb ready to travel popup trailer, 3500lbs towing my civic on a tow dolly (a lot of hitch weight with a front heavy car), pulling 3 trips with a 3700lbs GVW uhaul 12ft trailer, and rescuing 3 stuck vehicles (including a 6500 lb cargo van) and the hitch is hanging strong. Most of all, I LOVE that our van doesn't scrape like it used to, love it, love it.

[springoflife]

Is ground clearance only an issue on "newer" Siennas? I have a 1999 XLE with a Class III Reese hitch (2" box). I have 11-1/2" to the lowest point of the hitch!