WTF with those measurements. What are they from, The pick up?? I measured my 32 for track width and came up with 56" If you are generous and only remove 2" for the pivot stuff., you have an A+B measurment of 56-2 /2= 27" The spring is assumed as a 29.5 so 1/2 is 14.75. You have to remove 1" from that because the arm does not pivot right under the center of the spring. 14.74-1=13.75 for the B dimension Load factor = A+B/B= 27/13.75 = 1.96 Pretty close for a guess. Also what I said in the first place. You called me out to explain my "theory". Well there it is. I'm done
Measurments are from a 1932 Ford I have here on the table. 56" C-C on the wheels, halved is 28 = A+B (not including the pivots are actually moved out by an inch so 27") 34" eye to eye on the spring at installed dimensions, halved is 17 = B 1000(28)/17=1,647 1000(27)/16=1,687 1000(26)/15=1,733
You have to remove room for the joints in the middle. At least 2" . Prob. 3 I have never seen a 34 " spring for a deuce. Most are 29.5" Don't measure to the spring hangers in the axle, only to the center of the shackle in the spring. The spring would not connect at the same B dimension as a standard axle. 1" must be removed from the B dimension also because the axle half is shortned that much.
I edited it. Do you need a picture of a 34" spring? I have about 6 of them. I also have a few dozen axles around here with perch pin bosses for the shackles that measure 35"+ inches depending on which spring perch used.
It's amazes me all these places the make suespension parts aren't coded to aws or astme standards. Luckly nobody got hurt cuz you can't replace a life with a free product upgrade. Just my 2 cents
Andy, this is the car I am using for reference material. In reality, shouldn't we be using the actual connection of the spring to the axle instead of the the length of the spring, because the shackle is just extending the point of load.
Please send pic of 34 " spring. I have a pile of 31.5 stock springs. Need a pic? These are the longest I have seen. How would you use a 34 " spring on an axle with 35 " perch bolt centers?? LOL You need to edit some more. The B dimension need to be shortened the 1" also as the axle does not come to the center of the spring. Keep working on it.
NO!!! The shackle is free to rotate. It can pull in and push down The pull in load is transfered to the center pivot. Only the free to rotate end of the spring counts. You can replace the shackle with a wood block and the forces remain the same.
That spring dead flat is 34" long in the picture above. The way I have always measured springs because it doesn't take into account for arch. For the purposes of figuring spring rate this is vital information as is the number of leaves, width and how the ends are treated. The installed width with the shackles, perch to perch is 34.5". This number is a constant as is the 56" track. The only thing we are debating here is the inner fulcrum length and it's effects. I am going to fight you on this because the shackle and perch is very important here. The shackle is no different than a pushrod and rocker arrangement. The load is figured from the point of contact, not the end of the spring. We could put a 10" spring in this and run a 12" long shackle and the point of contact would still be the same. To remove the shackle and place it directly on the axle would change the point of contact and then change A dimension. A is a constant 11" Moving the fulcrum end of B outboard by one inch only shortens the B side of the fulcrum. A+B=AB (11+17=28, from center, no fulcrum) (11+16=27, from fulcrum moved out one inch)
I thought we did cover the intent of the original post pretty well. Or are we just waiting for the official response from Brent? Maybe he will chime in with a popular response from his competitor, something along the lines of "he used his brakes while driving over railroad tracks" or other fun excuse.
PM me the details if you like. The suspension should be able to take a pretty good pounding from bottoming out. It however cannot take repeated abuse from springs that are too soft of shocks that are too long unless it is designed to do so. So far I have not seen an aftermarket hot rod suspension designed to do so.
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