Fifth wheel trailer towing (trailer not level)
#16
05-24-2004, 03:16 PM
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Originally Posted by fellro86
I figured that is the springs causing that, as when loaded it shoulld be sitting level, so what you're saying is that in effect the are "jacking up" the rear fo the 350's?
#17
06-14-2004, 09:29 PM
#18
06-17-2004, 12:03 AM
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#19
06-17-2004, 12:20 AM
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Originally Posted by psdpower
So if I put a 6 inch block in the rear of my F350 does it become a F450??? Seriously changing block height changes the height of the truck not it's capacity. I know what you guys meant but some people may not just, thought I'd clarify.
#20
06-17-2004, 06:17 AM
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Originally Posted by johnsdiesel
Of course you can't just keep adding block height, but the added 2" does add "capacity" because it takes more weight for the truck to sit level. Also, we were comparing SRW trucks, not duallies. Everything on the F250/350 SRW is the same except for the blocks, so...
#21
06-17-2004, 10:56 PM
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Originally Posted by johnsdiesel
Of course you can't just keep adding block height, but the added 2" does add "capacity" because it takes more weight for the truck to sit level. Also, we were comparing SRW trucks, not duallies. Everything on the F250/350 SRW is the same except for the blocks, so...
#22
06-17-2004, 11:19 PM
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Originally Posted by psdpower
Blocks don't change the weight carrying capacity of the springs. Yeah with the same load and taller blocks the truck will be more level but that doesn't change the fact that the springs are over loaded. And there are so many different part numbers for rear springs on SDs, saying the block height is the only difference is not really true. If F250s and F350s had the same spring rate then they would be rated for the same payload (SRW). The frame and the rearend is the same so why would Ford even bother with 2 models?
Ford offers the 2 models probably because it is cheaper in some states to register a 3/4 ton truck and the insurance is less in some cases.
There has been a lot of confusion on this topic which is why there is now a post in the Super Duty FAQ. All of the information there is from Ford publications. Everyone in that forum got tired of digging up the same proof over and over again when these posts come up to prove that the blocks are the only real differences.
From the FAQ:
The question that seems to keep coming up week after week is
" What is the difference between a F250 and a F350"
Here it is:
There are 3 differences between the SRW 250/350...
1) F-250 vs F-350 badges
2) 2" rear spacer block in 250 vs 4" in the 350
3) *most important* GVWR for F350 SRW is 9900 in most states and the F250 8800 in most states.
From 99 to mid 2001 the srw trucks came with a Dana 50, Ford started using the Dana 60's on all F250/350's from mid 01 to present ,the front axle is identical on both trucks, including springs.
Springs in the Source Book are EXACTLY the same:
Front Leaf 250/350
3600lb 1.12"(thickness) 55.63"(length) 3.00"(width) 350(deflection)
4000lb 1.18"(thickness) 55.63"(length) 3.00"(width) 370(deflection)
4400lb 1.18"(thickness) 55.63"(length) 3.00"(width) 390(deflection)
4800lb 1.18"(thickness) 55.63"(length) 3.00"(width) 410(deflection)
5200lb 1.18"(thickness) 55.63"(length) 3.00"(width) 430(deflection)
6000lb 1.25"(thickness) 55.63"(length) 3.00"(width) 470(deflection)
Rear Leaf 250/350
6830lb 6(leaves) 3.86(thickness @ pad) 58.1"(lenght) 3.00"(width) 320/670/1209(deflection lbs/sq") 3603(rating@pad lbs/spring)
Rear leaf DRW
8250lb 6(leaves) 3.95(thickness @ pad) 58.1"(lenght) 3.00"(width) 350/730/1270(deflection lbs/sq") 4187(rating@pad lbs/spring)
" What is the difference between a F250 and a F350"
Here it is:
There are 3 differences between the SRW 250/350...
1) F-250 vs F-350 badges
2) 2" rear spacer block in 250 vs 4" in the 350
3) *most important* GVWR for F350 SRW is 9900 in most states and the F250 8800 in most states.
From 99 to mid 2001 the srw trucks came with a Dana 50, Ford started using the Dana 60's on all F250/350's from mid 01 to present ,the front axle is identical on both trucks, including springs.
Springs in the Source Book are EXACTLY the same:
Front Leaf 250/350
3600lb 1.12"(thickness) 55.63"(length) 3.00"(width) 350(deflection)
4000lb 1.18"(thickness) 55.63"(length) 3.00"(width) 370(deflection)
4400lb 1.18"(thickness) 55.63"(length) 3.00"(width) 390(deflection)
4800lb 1.18"(thickness) 55.63"(length) 3.00"(width) 410(deflection)
5200lb 1.18"(thickness) 55.63"(length) 3.00"(width) 430(deflection)
6000lb 1.25"(thickness) 55.63"(length) 3.00"(width) 470(deflection)
Rear Leaf 250/350
6830lb 6(leaves) 3.86(thickness @ pad) 58.1"(lenght) 3.00"(width) 320/670/1209(deflection lbs/sq") 3603(rating@pad lbs/spring)
Rear leaf DRW
8250lb 6(leaves) 3.95(thickness @ pad) 58.1"(lenght) 3.00"(width) 350/730/1270(deflection lbs/sq") 4187(rating@pad lbs/spring)
Last edited by johnsdiesel; 06-17-2004 at 11:29 PM.
#23
06-18-2004, 12:21 AM
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Go to Ford and try to order rear springs, they want to know cab configuration, bed length, and gvw. If they were all the same you could just walk in and say " I got a Super Duty give me some new springs". Who cares if the truck sits level if the springs are overloaded, there overloaded. A given spring will only support a given amount of weight regardless of whether it is sitting on the axle or five feet above the axle. Blocks cannot change the ability of a spring to hold weight.
#24
06-18-2004, 12:30 AM
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As I said, that is from the Ford source book. The blocks are different. Some are tapered and some are not depending on truck configuration. I find it diffacult to argue with the Ford source book.
Of course the spring can't handle more weight because of the block, but I'm talking about the truck sitting level which is a different issue. It does make a difference in the handling of the vehicle, because it will sit level with more weight on the springs.
The info you give at Ford or any auto parts store is automatic no matter what you are buying. When I bought my last fuel filter they went through the whole series of questions. The only information that they needed was that I had a 1997 PSD, not 4x4, super cab, longbed, etc.
If you dispute what I quoted from the FAQ please show me/us where it says something different in the ultimate source, the Ford source book. Otherwise it is not first hand information.
Of course the spring can't handle more weight because of the block, but I'm talking about the truck sitting level which is a different issue. It does make a difference in the handling of the vehicle, because it will sit level with more weight on the springs.
The info you give at Ford or any auto parts store is automatic no matter what you are buying. When I bought my last fuel filter they went through the whole series of questions. The only information that they needed was that I had a 1997 PSD, not 4x4, super cab, longbed, etc.
If you dispute what I quoted from the FAQ please show me/us where it says something different in the ultimate source, the Ford source book. Otherwise it is not first hand information.
#25
06-18-2004, 07:45 AM
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What everyone seems to miss is the blocks have nothing to do with load capacity of the truck. Yes the springs are the same, but the tire pressures are different from the 250 to 350. The blocks may be different but tire pressure is how they are getting the different weights.
Last edited by ownermsc; 06-18-2004 at 07:49 AM.
#26
06-18-2004, 11:35 AM
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The tires are the same load range E for both trucks. Yes, blocks do have to do with the load capacity. Ford would not design a truck that sagged when loaded to the maximum payload, therefore the extra height of the blocks allows the F350 to hold MORE WEIGHT before sitting level. So, in a sense the blocks don't add to the ability of the springs, but they do add to the ability of the truck to hold weight and sit level without sagging.
#27
06-18-2004, 03:11 PM
Along with tire pressure , the blocks do have something to do with load capacity.
We know the springs are the same from a 250 to a 350(fact) so with the taller block, ford gets a higher capicity rating for the 350's.
The spring rate doesn't increase because of the blocks, but on paper they are able to obtain a higher rating.
We know the springs are the same from a 250 to a 350(fact) so with the taller block, ford gets a higher capicity rating for the 350's.
The spring rate doesn't increase because of the blocks, but on paper they are able to obtain a higher rating.
#28
06-21-2004, 10:00 PM
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Tire pressure is not how they increase capacity either, both 250s and 350s come with the same load range E tires. As far as the spring issue goes, Ford lists 5 different part numbers for 250 and 350 4wd SRW trucks. Two for 250s and 3 for 350s. None of the part numbers are the same. I don't think Ford would give the same part 5 different numbers. Still think I'm wrong? The computer clearly states the part numbers are not interchangeable, as doing so may adversely affect the trucks payload. Info came from a trusted friend who is also the parts manager at the local Ford dealership. Class dismissed.
#29
06-21-2004, 10:26 PM
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Post from the source book like was done already. Class is in session. Parts were already listed directly from the source book. Can you do the same?
No offense, but the last parts manager I dealt with ordered the wrong part for my truck twice.
No offense, but the last parts manager I dealt with ordered the wrong part for my truck twice.
Springs in the Source Book are EXACTLY the same:
Front Leaf 250/350
3600lb 1.12"(thickness) 55.63"(length) 3.00"(width) 350(deflection)
4000lb 1.18"(thickness) 55.63"(length) 3.00"(width) 370(deflection)
4400lb 1.18"(thickness) 55.63"(length) 3.00"(width) 390(deflection)
4800lb 1.18"(thickness) 55.63"(length) 3.00"(width) 410(deflection)
5200lb 1.18"(thickness) 55.63"(length) 3.00"(width) 430(deflection)
6000lb 1.25"(thickness) 55.63"(length) 3.00"(width) 470(deflection)
Rear Leaf 250/350
6830lb 6(leaves) 3.86(thickness @ pad) 58.1"(lenght) 3.00"(width) 320/670/1209(deflection lbs/sq") 3603(rating@pad lbs/spring)
Rear leaf DRW
8250lb 6(leaves) 3.95(thickness @ pad) 58.1"(lenght) 3.00"(width) 350/730/1270(deflection lbs/sq") 4187(rating@pad lbs/spring)
Front Leaf 250/350
3600lb 1.12"(thickness) 55.63"(length) 3.00"(width) 350(deflection)
4000lb 1.18"(thickness) 55.63"(length) 3.00"(width) 370(deflection)
4400lb 1.18"(thickness) 55.63"(length) 3.00"(width) 390(deflection)
4800lb 1.18"(thickness) 55.63"(length) 3.00"(width) 410(deflection)
5200lb 1.18"(thickness) 55.63"(length) 3.00"(width) 430(deflection)
6000lb 1.25"(thickness) 55.63"(length) 3.00"(width) 470(deflection)
Rear Leaf 250/350
6830lb 6(leaves) 3.86(thickness @ pad) 58.1"(lenght) 3.00"(width) 320/670/1209(deflection lbs/sq") 3603(rating@pad lbs/spring)
Rear leaf DRW
8250lb 6(leaves) 3.95(thickness @ pad) 58.1"(lenght) 3.00"(width) 350/730/1270(deflection lbs/sq") 4187(rating@pad lbs/spring)
Last edited by johnsdiesel; 06-21-2004 at 10:35 PM.
#30
06-21-2004, 10:46 PM
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Sorry you've had bad luck with your parts guy but mine has never steered me wrong. You stated in an earlier post that the "source book" info was posted by another FTE user. How do you know your not just passing along another person's misinformation. I was looking at the computer while my friend looked up the part numbers, so my info is first hand. I was in a hurry and didn't copy down the part numbers even though I had a feeling I might need them. I'll have him print the info for me and post it when I get it.