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Why the hell do people in SUV's slow down to a crawl(34 posts)

Why the hell do people in SUV's slow down to a crawlpurplepaul
Apr 26, 2003 7:43 PM
when going over a pothole? I mean, aren't those things, when they're not flipping over, supposed to be able to traverse streams and mud puddles?

Here in NYC, where most people seem to have gone over to the dark side, traffic jams can happen simply because their 4 ton SUV's are too delicate to go over a bump in the road.

Stop the insanity!
Yeah and...Spoke Wrench
Apr 27, 2003 5:34 AM
when you pull up to a traffic signal, how do you guess which line of cars is going to move faster? My rule of thumb is that the faster they look standing still, the slower they go down the road.
Yes the suspension is strong...hycobob
Apr 27, 2003 12:30 PM
but not as strong as a thousand pot-holes. They will go out of alignment too, just like those old Yugos in your local landfill; only they aren't disposable.
Did a column on that once; got hate mail for weeks...cory
Apr 27, 2003 8:20 PM
I'm a newspaper columnist, and three or four years ago I did a column on that--"You spend 35,000 bucks for a vehicle that's supposed to go anywhere, and then you have to slow down to 2mph and baLUMP, baLUMP, baLUMP, baLUMP over a speed bump my Honda will take at 45..." I got mail for weeks either telling me I was a d!ckhead or explaining how the sophisticated suspension system of today's SUVs (right, like it's SO different from a '50 Dodge pickup) was calibrated blah blah... Might be time to do that again.
regardless of the vehicle...why would you want to abuse it? (nm)ColnagoFE
Apr 28, 2003 7:02 AM
No abuse involved--it's within the design parameterscory
Apr 28, 2003 7:37 AM
For it to be abuse, you'd have to be asking the POS to do something it isn't designed to do. Vehicle suspension is designed to absorb bumps, and they sell those things on their offroad image. You're saying they won't handle parking lot speed bumps?
Are cars desinged to handle speed bumps are 45MPH?Kristin
Apr 28, 2003 7:45 AM
Even if your off-roading your not doing 45 MPH. And I think its debatable that SUV's are designed for off roading anymore. I would trust a true Landrover (jeep body) to that, before I'd trust and SUV.
It might handle themColnagoFE
Apr 28, 2003 8:20 AM
but it isn't GOOD for them and they will break down sooner. I save the big impacts for read off-roading when you don't have a choice.
yup, studies show potholes cost in damage to carsDougSloan
Apr 28, 2003 9:13 AM
What potholes cost drivers

Drivers in the Detroit-Ann Arbor area spend an average of $1,416 extra over the lives of their vehicles to Þx damage to their cars caused by poor road conditions, the highest average in the country, according to the Surface Transportation Policy Project in Washington.

AAA Michigan estimates pothole damage repair costs at:

Tires: $50 to $150

Tie rod: $50 to $150

Control arm: $150 to $300

Wheel alignment: $50 to $150

Ball joint: $75 to $150

Wheels: $50 to $500
But SUV's aren't cars, they're light trucks.purplepaul
Apr 28, 2003 9:47 AM
And advertising studies show that the typical SUV buyer wants to be seen as rugged and outdoorsy. So, again, why would mister or miss rugged individualist slow their gargantuan truck down to 1/2 mile per hour to gingerly cross some pavement that cars don't even slow down for? Perhaps SUV's aren't well suited to city driving.
Apr 28, 2003 10:03 AM
I don't do it, nor have I observed "slowing down to 1/2 mile per hour." Seems like a false premise to me, at least in general.

I explained my theories, nonetheless.

If the measure of suitabity for city driving is driving through potholes at the speed limit, then Hummers (the originals) are probably best.

Kind of a paradoxpurplepaul
Apr 28, 2003 11:43 AM
They're so heavy they cause more potholes than cars, yet they must slow down, so they're slower than cars.

Pisses me off.
you must really hate 18 wheelers then (nm)ColnagoFE
Apr 28, 2003 2:25 PM
Not really. At least they have a reason for being so big. nmpurplepaul
Apr 28, 2003 2:38 PM
sure about that?DougSloan
Apr 29, 2003 7:17 AM
You have several potential false premises there.

1. Do SUV's cause more potholes? Any proof of that, other than intuition? Could well be that potholes have a dozen other causes, and vehicle weight is only one factor. Plus, there could be a threshold where vehicle weight starts to become significant; big difference between cars/SUVs (2,000-6,000 pounds), and then 80,000 pound trucks. Many SUVs aren't even as heavy as some sedans, too.

2. They "must" slow down? No, they are not required to. Believe me, I know.

Yes, I'm surepurplepaul
Apr 29, 2003 9:46 AM
1. They're significantly heavier than your average car so, therefore, they contribute more to road wear. Unless, of course, you believe that a heavier vehicle can tread more lightly than a lighter vehicle. Most SUV's are significantly heavier than cars because they have to be in order to get around government fuel economy standards.

2. I said they "must" slow down based on the behavior of so many boneheaded, rugged, outdoor-type drivers here in NYC who simply cannot bear to have their precious off road truck encounter any vibration that should make it absolutely clear that they're not, indeed, the rugged outdoor type.
Apr 29, 2003 10:02 AM
My point was that roads may be designed to suffer no damage whatsoever from cars, light trucks, or SUVs, and it's only the heavy trucks and other factors (like freezing, salt, etc.) that cause problems. Your assumption could well be false. Do we really know one way or the other? Or, even assuming that heavier will always cause more damage, is the difference between a 4,000 and 6,000 pound vehicle a 1% difference in actual wear within the otherwise useful life of the pavement, anyway? That is, is the difference truly significant, or are all of us just speculating?

Apr 29, 2003 10:18 AM
that a 50% increase in weight will have a significant impact on road wear. Certainly semis will create the most wear, but they are few in number relative to cars and "light" trucks. All vehicles will contribute to road wear. Heavier ones will contribute more than lighter ones except, perhaps, on cobble stones which don't really exist in this city any more. But if they did, I'm sure your average SUV would be crawling over them, afraid their tires will explode and doors will fall off. Then again, since SUV's are so prone to flipping over, perhaps it's best for them to crawl. I just wish they'd not do it in front of me.
guessing about speculatingDougSloan
Apr 29, 2003 10:24 AM
So, by the same reasoning, and since "All vehicles will contribute to road wear," a 250 pound guy on a bicycle will wear the road twice as fast as a 125 pound rider? Therefore, the road, with only bikes on it, will then last 50 years instead of 100 years?

guessing about speculatingpurplepaul
Apr 29, 2003 11:25 AM
If only roads around here would last 50 years. Of course a 250 pound bicyclist wears out the road faster than one half his weight. Who knows what the rate difference would be. My point is, SUV's, which were designed to be used off road and for hauling heavy loads are not a good choice for moving one person around the city.
SUV design and CAEryder1
Apr 29, 2003 5:10 AM
This thread makes me chuckle a bit as does knowing that the SUV's I help design will only see the loads they are capable of for about 4% of the customers out there. All the SUV's (even the light small ones) at my company (to be nameless) are held to the same durability requirements as the big pick-ups. I do design and CAE on frames and suspension components. The loads are huge. The durability circuits are brutal - 30 mph over broken concrete with holes like a foot deep, it's hard to even keep the vehicle in control over the surface. This leads to the heavy vehicle and poor gas mileage. The big ladder frame of an SUV needs to be beefy enough to handle these rediculous loads that hardly any typical user will see and needs to be stiff so, it will be less noisy and more car-like ride (more weight). All this so some yahoo can look tough and percieve they're safe. The bright spot is working on the hybrids that will come out. I hope they sell..........
speaking of hybridsDougSloan
Apr 29, 2003 7:13 AM
I saw on TV yesterday the new Toyota Prius; bigger, more powerful, AND better gas mileage, 55 combined. Coming out in the fall.

speaking of hybridsryder1
Apr 29, 2003 9:40 AM
This is an area where the Japenese will eat the lunch of the big three. With very tough reg's at home, they've been perfecting hybrid technology for years while we've been caught up in making bigger and bigger SUV's. Once our hybrid finally comes out, I'm not sure people will pony up for an extra $4k to get a mere 38 mpg for a small SUV. We'll see.........
I'm a-guessin' you work for Ford...girchygirchy
May 1, 2003 7:17 AM
As far as I know, they're the only domestic manufacturer coming out with a small hybrid SUV any time in the near future. I'll certainly consider it when it comes time for me to purchase a new car, but knowing me, I'll probably go for a Mazda6 or RX-8, perhaps a WRX. The only thing big vehicles (trucks and SUVs) are good for is work, IMHO.
Aren't they moving away from ladder frames though?ColnagoFE
Apr 29, 2003 8:03 AM
I know the new Explorers use a don't have leaf springs in the rear. Seems like SUV manufacturers are finally realizing that people mostly use these for hauling boats and kids on road and not off-road.
Aren't they moving away from ladder frames though?ryder1
Apr 29, 2003 9:33 AM
New Explorers use an independant supension or "4-bar" with an upper and lower control arm similar to a car. Just one more way to make a truck ride more car like but, it still has to pass all the same requirements for durability, towing, etc. Better ride but, more expensive. As far as frames, most SUV's like Explorer size are still full frames however, smaller ones like Escape are unibody. Unibody's make the vehicle lighter and have a lower step in height (more friendly for heels and skirts) however, you won't be hauling your boat or trailer with one.
Because they know it buggs you....asphalt assault
Apr 28, 2003 7:15 AM
...With the price of any car these days it just does'nt pay too thrash 'em.

$$$ spent on car repairs means less $$$ to spend on bike stuff.
I've never seen one brake for a pothole. They're usuallyKristin
Apr 28, 2003 7:27 AM
too close to my a$$ to see it coming!!! And I'm not a slow driver. I do a consistent 8-10mph over.
stiffness vs. durabilityDougSloan
Apr 28, 2003 7:32 AM
I don't think it's a matter of durability or "can it take it," as most SUVs are built more durable and designed for bumps, beginning with tires with taller sidewalls, then longer travel suspension, etc.

However, I think many don't bomb through potholes and speed bumps, not because of durability concerns, but because SUVs are usually sprung more stiffly so they don't bottom on really rough terrain, meaning the jolt to the body is higher.

Also, rear solid axle trucks/SUVs have a lot of unsprung weight, so the suspension reacts more slowly to wheel movement, which transfers more of the bump to the chassis and ultimately to you. This can make them more rugged, but less comfortable.

If you are driving your Honda Accord (or whatever) through potholes at the speed limit, you are probably greatly accellerating the wear on your suspension, bushings, shocks/struts, and tires. Alignments will likely be needed more often, and when the car gets old, it's going to creak like a retired NFL lineman in the morning.

They are locating and engaging their 4WD function. (nm)czardonic
Apr 28, 2003 9:03 AM
or grabbing their Starbucks cup so it doesn't spill nmDougSloan
Apr 28, 2003 9:42 AM
or taking it slow so the DVD player doesn't skip. (nm)czardonic
Apr 28, 2003 9:47 AM
LOL. That was a good one. (nm)purplepaul
Apr 28, 2003 9:43 AM
There's more utility in a screwdriver with no handle...No_sprint
Apr 28, 2003 10:25 AM
than *most* SUVs.