Brakes stop trucks. Not weight. A heavier diesel will need bigger brakes than a lighter truck to stop the same load.
Ford RAPTOR vs Diesel????
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Brakes stop trucks. Not weight. A heavier diesel will need bigger brakes than a lighter truck to stop the same load.
It all comes down to friction, both in the brakes and the contact patch between the tire and the road. Both are a limiting factors at some point.
If the tow rig does not weigh enough, you can have all the braking force in the world, but then the limiting factor is the foot print (weight per square inch) of the tires on the road and the frictional co-efficient of the road surface. Sure you can lock up the tires and with a light truck or even a heavy truck with big meats on it, it still is just going to just skid until the trailer's momentum is diminished to a point that the friction between the tires and the road can start grabbing.
With a small tow vehicle you have neither the braking capacity nor the weight / contact area to be effective. Just because you can tow with any vehicle, doesn't mean you should. FWIW
If the tow rig does not weigh enough, you can have all the braking force in the world, but then the limiting factor is the foot print (weight per square inch) of the tires on the road and the frictional co-efficient of the road surface. Sure you can lock up the tires and with a light truck or even a heavy truck with big meats on it, it still is just going to just skid until the trailer's momentum is diminished to a point that the friction between the tires and the road can start grabbing.
With a small tow vehicle you have neither the braking capacity nor the weight / contact area to be effective. Just because you can tow with any vehicle, doesn't mean you should. FWIW
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mike_s
Well-known member
True, a heavier truck will need bigger brakes. But that's not the point in having a heavier tow vehicle. If 2 trucks are towing a 7500 lb trailer, one truck weighs 5k and the other 8k which do you think is going to command the trailer and not be pushed around?
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The heavier truck will tow better. It will not stop better. If heavier vehicles stop better why can't my 2500 stop shorter than a Ferrari?
A heavier truck will have more psi to the ground than a lighter one, and therefore better traction. But it needs that increased traction to help stop its added weight.
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mike_s
Well-known member
But the point is, hook that Ferrari and your truck up to a 8k load, and your 2500 truck will stop far short of the Ferrari. It simply has more presence due to it's weight.
Here's something you can try at home... Hook your 4 place trailer up to your sportsman or razor ATV, get going about 20 mph and slam on its brakes. That trailer is going to shove that ATV down the road like a kid with a tonka truck. Now try it with a full size pickup truck. Bet it stops with no issues.
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But the point is, hook that Ferrari and your truck up to a 8k load, and your 2500 truck will stop far short of the Ferrari. It simply has more presence due to it's weight.
Here's something you can try at home... Hook your 4 place trailer up to your sportsman or razor ATV, get going about 20 mph and slam on its brakes. That trailer is going to shove that ATV down the road like a kid with a tonka truck. Now try it with a full size pickup truck. Bet it stops with no issues.
take your full size truck and loaded four place and slam the brakes.
Now throw 2,000lbs in the bed and do it again. You have way more "presence" and it takes a lot longer to stop that "presence". It's pretty basic physics.
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mike_s
Well-known member
Would be the similar as with the trailer, but would not skid. by your physics, if I had an engine with enough power, I could hitch on to a flat bed semi trailer with my duramax and tow my 8630 John Deere with the big boys. If you have a skid with 5 pounds on it, it's going to slide easier than a skid with 10 pounds on it. Given that most half ton and 3/4 ton trucks have the same amount of rubber contact patch on the ground, the same principal applies, a lighter truck with more weight pushing it (it's on the trailer, not the truck) is going to skid easier than a heavier one. I think the part that is confusing for some is the fact that the trailer doesn't increase the weight of the tow vehicle by the amount it weighs, but it does increase the total mass of the combination. 2 trucks with equal weights but one with monster wide tires will not stop equally either. The one with less ground pressure will skid.
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Take a stock suzuki samurai and measure the distance it takes to stop from 60 mph.
Now take that samurai put a huge lift and 44in boggers on it and perform the same test.
Or... i can save u time and tell u the results from Petersons 4wheel and off road.
The huge lift and 44inch boggers stops quite a bit sooner. Because of more traction. Even though it weighs more.
The little tires locked up and skid. The big tires would not lock up.
Now take that samurai put a huge lift and 44in boggers on it and perform the same test.
Or... i can save u time and tell u the results from Petersons 4wheel and off road.
The huge lift and 44inch boggers stops quite a bit sooner. Because of more traction. Even though it weighs more.
The little tires locked up and skid. The big tires would not lock up.
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mike_s
Well-known member
Interesting, I had the exact opposite result on my 94 GMC. 33x12.50s stopped it pretty good, the 38x15.50s I have on it now just like to slide.
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U went from 33 to 38 thats 15% larger. Rubber compound and tread play a big part also.
Samurai went from 28-44 that is 60% larger. that is 4 times the the amount u increased.
My point is there is a lot more than just weight that determines stopping distance and control.
Samurai went from 28-44 that is 60% larger. that is 4 times the the amount u increased.
My point is there is a lot more than just weight that determines stopping distance and control.
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Jaynelson
Well-known member
Lots more - brakes, tires yada yada. Mike s - the heavier truck will handle the load better in general than the lighter one, given equal suspension, brakes, etc. but given the trailer is braking at threshold (regardless of what it's hooked to), the lighter truck will stop faster with equal brakes and tires. Just as a lighter truck will accelerate faster given the same engine, trans and gears. No one adds weight to their race car to make it stop and accelerate quicker due to more traction.
Suzuki thing is somewhat comparable, but some different variables.
Suzuki thing is somewhat comparable, but some different variables.
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mike_s
Well-known member
The width is what makes the difference, not the height. Granted a 28 inch tie is probably not very wide anyways. The analogy still applies, is it easier to pull a sled with 2 kids on it or 1?
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Jaynelson
Well-known member
Actually...for acceleration and deceleration....the height plays a very large factor.
If you have a tire of a given size that has X amount of traction, and have a choice to upgrade to a tire that is 10% wider (but the same height), or 10% taller (but the same width.....the taller tire will have greater traction than the wider tire. Contrary to popular belief.
Now, in the real world - trucks of different sizes have different brakes, suspensions, tire sizes and types, etc, etc, etc, and all of that comes in to play. And I agree with you that a heavier truck in general is less affected by trailer towing, as the trailer is a smaller percentage of the overall weight. But for acceleration and deceleration, the formulas are very simple and lighter weight wins every time given all other variables are the same.
If you have a tire of a given size that has X amount of traction, and have a choice to upgrade to a tire that is 10% wider (but the same height), or 10% taller (but the same width.....the taller tire will have greater traction than the wider tire. Contrary to popular belief.
Now, in the real world - trucks of different sizes have different brakes, suspensions, tire sizes and types, etc, etc, etc, and all of that comes in to play. And I agree with you that a heavier truck in general is less affected by trailer towing, as the trailer is a smaller percentage of the overall weight. But for acceleration and deceleration, the formulas are very simple and lighter weight wins every time given all other variables are the same.
You keep referencing sleds and skids, are you assuming the tires will be locked up during braking?
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mike_s
Well-known member
Locked up, no. But even with ABS there is a percent of slippage. You learn that and see it when you goto accident investigation classes. Can't remember the figures exactly but there is a generalization for the percent of skid still present given vehicle weight and contact patch.
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