56 or 63?

[tyler__820]

Ok brotherhood I know there is a search button and I have searched to my hearts content, so I'm asking everyone. Tommarow I will he going to the u pull it and was wondering if I should get 56" or 63" leafs for the rear of my truck? Any help and or advice would be nice. Oh and of course pic whoring is strongly advised!

 

[DeviousK5]

Ill play along. First what vehicle?whats your intended usage of the vehicle? What are your fab skills like?

56's are a bolt in affair if you have a shackle flip. 63's are not ,both the front hanger and the shackle flip will both have to be moved-unless you want an extra 6" or so of wheelbase.

I put 63's in the back of my blazer and plan love it. But on the other hand you never really hear anyone bitchin about the lack of comfortable ride or flex out of a pair of 56's.

Obviously the 63's hang farther back on the truck and will more easily get hung up on things.

Sorry no pics to whore(theres literally not a single pic of my truck here..Shhh dont tell anyone)

 

[sweetk30]

and few more bits of info.

if swapin in to a truck the saddle tanks wont fit anymore with 64" springs. the front hanger goes to far forward to keep the axle centered.

and 56" swap is easy if going from 52" flip the brackets left to right if flip kit. or if the extra holes are behind the rear hanger on the frame just pop the rivits and move it back 4" and bolt back up.

and yes we need more info for what you plan to do with this truck/blazer/burban

 

[ryoken]

the other thing to keep in mind is the rig will be MUCH more prone to axle wrap with 63's... the bigger the hp and tire the worse it will get... 56's here...

 

[tyler__820]

Oh sorry guys, well I have a one ton Chevrolet stepside, shortbox of course, it drives to the trails and never touches a trailer. Oh and I ditched the sadlle tanks and have installed a blazer tank and also have a shackled flip kit already on.

 

[1BEATK5]

I have 56's, and they work great. flex and ride well. easy to install since you already have the flip. thats me vote

 

[Stomis]

64s get my vote. I've got rear 56s and personally I dont think they have enough length to retain a decent spring rate and get good flex out of them.

 

[toomany]

I started my 64 swap last night. I can only move my rear hangers back so far (5"?) because of the way I cut my frame...so my wheelbase will be getting shorter.

 

[MJB774X]

springs

I'm planning on doing the swap too, I'd like to see some pics if anyone has them, I really want to go with the 63's but wrap has me concerned, I'm running a 396 with a 4 speed, I'd really like to move the axle as far back as possible, but I'd like to see what it looks like when the axle is pushed back a few or more inches on a k5, that pic would be nice too....I haven't been on here in years.. this site doesn't seem as active as it used to be.

 

[owenst7]

the other thing to keep in mind is the rig will be MUCH more prone to axle wrap with 63's... the bigger the hp and tire the worse it will get... 56's here...

You know, if people would quit trying to use the 3 leaf 64"s on a big truck, there wouldn't be this misconception. A K5 needs the spring rate of a 4 or 5 leaf pack, and the overload needs to stay in there. I have a 4 leaf pack plus the overload from a '95 4x4 3/4 ton and have zero wrap issues, even with a zero rate.

The 3 leaf packs that everyone uses because they think they will get a better performing suspension are meant for MUCH less weight on the rear suspension than a K5 has. It's not necessary, I have to bumpstop my springs as it is because they will easily compress beyond flat. The extra leaves don't effect droop because they aren't clamped to the main leaf.

Not to mention people remove the overload and wear out the main leaf. The overload is called an overload because it helps prevent the main leaf from being damaged when it is overloaded. Removing it will make it a lot easier to fatigue the main leaf, which in turn will increase axle wrap among other things. It's flat anyway, it's not like it does anything to the way the spring moves within its appropriate range of motion.

My 64"s are awesome, but it was a lot more involved than 56"s would have been because I had to punch out all those extra rivets. Main reason I went with 64"s was because it was a lot easier to find a good set at the junkyard. 56"s are usually pretty beat up due to being a lot older.

 

[ryoken]

i knew you'd reply... my prior argument still stands, it's not a misconception... it's simple physics..

you may not be having an issue, but generally over the decades, a longer spring has been shown to have way more tendency to wrap.. how much hp are you running?

 

[owenst7]

i knew you'd reply... my prior argument still stands, it's not a misconception... it's simple physics..

you may not be having an issue, but generally over the decades, a longer spring has been shown to have way more tendency to wrap.. how much hp are you running?

Weak motor, rock crawling with 40s though. HP wouldn't be relevant here, torque would. I would notice if there were wrap issues, I've spent a lot of time monitoring it because I can't afford driveline yokes.

It's funny you reference physics. I am a materials engineer with an emphasis in metallurgy and mechanical, and there's automotive engineers that agree with me. Not to mention I've done this whole thing once or twice just like you

We should agree to disagree here, but if you drag physics in to this, I will keep setting the record straight for the sake of the correct use of physics being displayed here.

Point is for the OP, if you decide to run 64"s, you're going to have axle wrap issues if you don't get a leaf pack for a heavier vehicle. Still flexes well, just don't make the mistake of grabbing a light duty pack and ending up with bad wrap issues. And ryoken, it is a misconception that 64"s will have bad wrap issues. They don't have to. A guy could run more leaves and not have that issue, like I've explained. My '96 that I've plowed with for the last 15 years doesn't have any axle wrap issues, even with an 800 lb plow and 1000lbs of gravel in the bed. 64"s are so flat that it's not going to noticeably impact the vertical travel.

 

[ryoken]

whatever dude.. your just smarter than me......

 

[NorCal_Chris]

longer spring = more prone to axle wrap.... period.

people dont run anti wrap bars on 63's just because it is fun. Hell there was a guy out whhen i was wheelin with a yota on 37s. 3 leaf 63s with overload and he was having BAD axle wrap on the rocks.

I would just do the 56's They will flex plenty good for you and less work to get them in there

 

[blazinzuk]

I have not seen a huge amount more axle wrap with 63 than with 56, ther is alot more to how much a spring will wrap than just its length, doesn't apply here much becausr neither spring is military wrapped or has extra leaves. My 63 do wrap but oddly enough not nearly as much as the toy guys using them. Mine do have an extra leaf in them but are totally shot after about 2 years of hard use.

In all reality a traction bar should be in the cards because all leaf springs will wrap.

I say whichever you find or want to do, traction bar will eliminate the big issue.

The 63 do droop out just a bit more than the 56s do

 

[boz42]

Both springs are impressive. I run 56's front & rear. I have no complaints.

They 63's are easier to find now, the 56's are easier to fit. In my mind that is really the only difference.

I am running 1/2 ton 56's both front & rear. They are a bit harder to find. I could not run the 56's rears without an anti-wrap bar.

PIC WHORE:

Only pic I could find showing the profile. My rear axle is moved back 5" or so. I am runnning my rear 56"s long side forward. The front is still sitting on 48" long 4" leafs in this pic.

56's front & rear:

 

[tyler__820]

Ok so i made my trip to the junk yard, and got me some new springs. i got mine off a mid 90's 1/2 ton suburban but i measured them and they were 59 inches long eye to eye? wtf well i guess ill settle in between 56 and 63.....

 

[Hogback Fabrication]

Ok so i made my trip to the junk yard, and got me some new springs. i got mine off a mid 90's 1/2 ton suburban but i measured them and they were 59 inches long eye to eye? wtf well i guess ill settle in between 56 and 63.....

Suburbans are different than pickups, they use ~60" rear springs.

 

[sweetk30]

well everyone b!tchen back and forth made you settle in the middle i see.

 

[tyler__820]

Huh i did not know suburbans had diffrent sized springs,guess i learn something every day, but on a side not i cant wait to get them in and improve further on my already decent flex.