Tow Vehicle

[peterh]

Is there really any difference in the front wheel drive and the AWD when towing something as light as the 13ft. Scamp?

I think that depends on what kind of AWD you get. On my Hyundai Santa Fe (and many other AWD vehicles, Subaru being the only exception I know of) only a minimal amount of energy is transmitted to the rear wheels most of the time. Before significant energy is moved to the rear wheels, the front wheels have to be spinning freely, and this kind of drive mechanics is of little help when you're towing because you've already lost traction on the front wheels where the loin's share of your power will always go.

The other thing about AWD on the Santa Fe (and many other vehicles) is it actually reduces your towing capacity. My AWD Santa Fe has a maximum tow capacity of 2200lbs; the FWD version can pull 2700lbs. (Assuming electric brakes.)

--Peter

[Patrick M.]

One frequently identified downside to the AWD is that it eliminates the underfloor storage space for a spare tire, so run-flat tires are used instead, which are expensive and have their own problems.

OT: Click and Clack discussed run-flat tires in their column today. Totally convinced me that this is something to avoid like the plague. Short tire life, very expensive to replace ($250 each), and requires special equipment to mount not yet widely available.

Of course, if one has lots of money and wants the benefit then maybe a good idea.

[peterh]

OT: Click and Clack discussed run-flat tires in their column today. Totally convinced me that this is something to avoid like the plague. Short tire life, very expensive to replace ($250 each), and requires special equipment to mount not yet widely available.

Of course, if one has lots of money and wants the benefit then maybe a good idea.

Might be true for some vehicles, but clearly not all of them. None of the AWD vehicles we looked at in 2001 had run-flats, and the Santa Fe we bought had a full-size spare.

--P

[Candi Woods]

Essentially, they are SUV/wagon and van versions of the same vehicle, and I believe that Sienna's longer wheelbase makes it the better tow vehicle; it certainly met our requirements better. For now, if you were to want a hybrid, the Highlander would be the only choice among these two, although there is a hybrid version of the Lexus SUV/wagon which also shares the same components.

Interesting...when I asked the salesperson about the difference in wheelbase between the Highlander and the Sienna he said it was "the same". Next time I'm bringing my own tape measure and checking it for myself. At any rate, the Highlander was too small for what we needed.

Thanks for sharing your personal experience, it's been quite helpful. Since we live where we get snow every winter I think the AWD is a good choice. I do hate those tires, though. Nowone in our town can fix them and the dealership is too far away to drive a flat into it. Imagine getting a flat tire somewhere in the middle of nowhere and the man at the local tire shop has never seen anything like it, much less knowing how to fix it. Bad News.

Candi

[Candi Woods]

Might be true for some vehicles, but clearly not all of them. None of the AWD vehicles we looked at in 2001 had run-flats, and the Santa Fe we bought had a full-size spare.

--P

The AWD versions have run flat tires standard on all of them. There is no choice. YOu get the AWD, you get the run flats. You could pay to have them removed but then you have no place for a spare. However, there's plenty of cargo space in the back to store it, it's just ugly and might mess up your carpeting.

Candi

[Chester Taje]

I have never heard of "Run Flats".Are they those stupid spair tires which are smaller than regular tire.?

[Candi Woods]

I have never heard of "Run Flats".Are they those stupid spair tires which are smaller than regular tire.?

My technical knowledge is limited but, they are a special tire that is made to be driveable even after they become flat. Of course, the driveability is not ideal and is only for emergency cases until you can get to a shop that can repair them. Except, most shops don't repair them so you may have to drive many more miles than you would have otherwise, just to get your tire fixed! Maybe the idea will catch on and many places will begin to repair them. But it's not forseable considering their cost.

Candi

[Andrew Gibbens]

Most run-flats will require replacement in the event that you actually use them as run-flats, by driving on them after losing pressure. However there is some dispute over this. The problem seems to arise because you can't see visible damage inside the (reinforced) tyre sidewall, as you can if a normal tyre has been driven on when flat.

There is even some uncertainty about whether it is safe to repair the tread area if punctured.

Most run-flats are significantly harsher-riding than normal tyres and some manufacturers fit softer bushes in the suspension to compensate, so you get harsh and wobbly!

It's not encouraging, is it?

Andrew

[Frederick L. Simson]

OT: Click and Clack discussed run-flat tires in their column today. Totally convinced me that this is something to avoid like the plague. Short tire life, very expensive to replace ($250 each), and requires special equipment to mount not yet widely available.

Of course, if one has lots of money and wants the benefit then maybe a good idea.

link to an earlier run flat tire discussion

This was my conclusion, too.

I have never heard of "Run Flats".Are they those stupid spair tires which are smaller than regular tire.?

Those are "Limited Duty Spares" a.k.a. "Doughnuts" which were meant to improve fuel economy by reducing the amount of weight of the vehicle.

[Brian B-P]

I think that depends on what kind of AWD you get. On my Hyundai Santa Fe (and many other AWD vehicles, Subaru being the only exception I know of) only a minimal amount of energy is transmitted to the rear wheels most of the time.
...

The other thing about AWD on the Santa Fe (and many other vehicles) is it actually reduces your towing capacity. My AWD Santa Fe has a maximum tow capacity of 2200lbs; the FWD version can pull 2700lbs...

Good points, Peter, to keep in mind when considering other AWD vehicles. I was referring specifically to the Sienna, which has a centre differential and 50/50 initial torque split (all wheels truly do drive) and the same tow rating regardless of AWD versus FWD. There are many ways to do AWD, and Toyota has pretty well done them all. Subaru specializes in all-wheel-drive, and does a fine job of it, but they're far from the only ones. The British invented high-performance on-road all-wheel-drive, and Audi popularized it.

Some vehicles have higher ratings with AWD (likely due to suspension tuning differences, or better stability in low traction conditions), and for most trucks the towing capacity is just reduced by the weight of the extra drive hardware. For the Sienna, the extra weight would reduce the cargo you can carry, and indirectly reduce the maximum trailer weight in combination with lots of cargo, which may be a consideration for Candi.

Might be true for some vehicles, but clearly not all of them. None of the AWD vehicles we looked at in 2001 had run-flats, and the Santa Fe we bought had a full-size spare.

I was referring specifically to the Sienna. This space-for-a-spare problem is likely one reason that most minivan makers do not offer AWD, especially since they are now making the seats fold into the floor. The other vehicles with run-flats are typically sports cars with big tires and too-small trunks (not typical towing candidates).

Candi, it sounds like you have a good handle on the run-flat tire situation. You do have the option of carrying a full-sized spare (and if you carry it all the time, using normal instead of run-flat tires), but the only good place to put it (if you don't want it on the roof rack) is in the well behind the wider side of the third row seat, which would then not be able to fold down into the floor... kind of like having some other brands of minivan

[Andrew Gibbens]

Those are "Limited Duty Spares" a.k.a. "Doughnuts" which were meant to improve fuel economy by reducing the amount of weight of the vehicle.

OK, I'm drifting off topic here, but you can think yourself lucky if you have one of these space-saver spare tyres. In order to save even more space, my car is equipped with a special collapsed, uninflated space-saver tyre - inside the centre of the spare wheel is an electric tyre pump that has to be used to inflate the spare tyre prior to use!

Andrew