Long Travel BS Thread

This. The combined rate of the two springs is much lower than the typical single rate you see so you get a lot better ride comfort, and rollover of course, but once the primary spring is removed from the equation (divider hits the crossover ring) then you ramp up to whatever rate the lower spring is.

The problem is fitting the TLG of the two springs + spring divider and not going into coil bing during stroke. Hence @tetten statement of a 12” body and cutting out the bucket.

 

So... which one of us is going to be the unlucky bastard who cuts their coil bucket out first? My vote is @tetten because he is cheating off my test for his 4link.

Odds are... it might be me.. I should do the engine cage while I am doing the roll cage... and that would be the time to do a 12" shock body.

 

I support that. I will tell you it won’t be me. I’m going to see if I can shove them on an 8” shock and if it doesn’t work I’ll probably try a 550 lb spring and/or leave the 600 I’m running now. I’m pretty happy with my last valving change. Limited dirt miles on it but from what I ran yesterday while aired up Im not too disappointed. A couple things to tweak as always.

I’ve got other things that need attention before I complain too much more about the front suspension. Lol

 

I got it fam, I'll take some measurements tomorrow and make sure a 14" won't fit and order whatever will work

Pfft you just turned in your answers to the 4link test before me and our answers were mostly the same

 

Yeah.
Much truth to this. There is a reason I beams “just work “. For starters the obvious, you can run a larger 12-16” shock up front with duel rate springs .
Less known reason is ; most off the shelf 2.5” shock pistons work well on trucks at that motion ration / shaft speed . You can always tune your shocks by valving (replacing shims on the main piston) but at some point (typical high shaft speed) the openings / orifices of the main piston (as it was machined in the factory) will determine the dampening characteristics that cannot be changed . Unless you machine a custom shock piston.
So, It just so happens most of the shocks work great at that weight (pickup trucks) at the shaft speeds I beam trucks have. With our sorry ass little LT a arm trucks going 3.5” Over using a pathetic 8” shock …you have crummy shaft speeds that you have to tune for that weight & motion ratio.

if you think I’m talking nonsense , ride in a Tacoma with a LT kit and a “dialed” 8” coil
Over. Then ride in some sloppy I beam truck with 14” coil overs . That magical combo of weight , travel , shaft speed and motion ratio will yield a way better ride for all types of terrain. Even with some base factory shock valving.
It’s definitely possible to tune a 8” coil over on a LT a arm truck. But the Margins are very tight to make it work for small , medium and big bumps !

 

so what you both are saying is you’ll have figured out all of the intricacies on the test so I can ace it when ready???

 

I disagree with a lot of your statement. Shaft speed isn’t the issue with either setup. In fact, IFS suspension has a lot lower shaft speeds than a lot of other setups due to the high motion ratio. So it’s not really a piston flow issue.

What you are ignoring in your comparison is the amount of travel you have available between the two setups. With an IFS truck, you’ve got very limited wheel travel and even less shock travel but are tying to do the same amount of work. Even on an LT kit you’re trying to dampen all comp forces in 4-5” of shock stroke. Even less on a stock length.

With beams you’ve got plenty of travel to work with giving you a lot more freedom in valving, etc in addition to running a dual rate which was mentioned.

 

Lt kits both produce travel at around 14”


That’s right the A arm is slower shaft speed . To compensate you run thicker shims … oh but wait now these shims are too thick for light chatter and small bumps . Ok looks like I need bypass shocks to make up for this….


As opposed to i beam with ideal motion ratio for the off the shelf shocks (main piston design). Shims will help you tune low and medium speed shaft speeds . Once you hit something big it’s essentially the main working pistons openings that will determine dampening.


just PM that accutune shock guy on here. He will back up my story.

 

Yeah, not going to spend my time doing that. Your post tells me everything I need to know about this conversation.

Happy 4th everyone!

 

come on we all know the real reason is because there's tons of those I-beam Fords chillin in southwest junkyards for dirt cheap cause mechanics gave up on dealing with them pretty quickly and the powertrain options weren't that great and outdated pretty quick as soon as the turbo 7.3s started coming around. Just a buncha guys with rough riders dreams and beercan budgets overhyping em

 

I mean I’ve built both LT a arm and LT I beam set ups (not installed someone’s “kit” but from scratch) and it’s almost always much more difficult to tune shocks and get the spring rates correct for an A arm truck ( especially if using stock pivot points and running 8” c/o’s. )

 

you essentially rephrased what I said. So , yes you are right ….

 

@Tacoma1192 I tried to creep on your build thread, but it looks like it was updated in '18. What front end are you running and what valving in your shocks? Not sure if you have tried this, but opening up your free bleed will help (but also increase body roll).... If you've been over all of this then just ignore me.

A big thing a few years back for ultra4 guys was to utilize a "gold valve" (Fox shocks), it is essentially a free flowing valve to create a significant amount of bleed in one bypass tube. Such that at ride height your valving was minimal to help get rid of chop. Now the "secret" is to just to drill a bleed hole in your main compression tube that manages your compression at ride height. This of course requires adding a second shock (bypass)

 

No…. Nice try, but just no.

No arguing here. Just having a conversation. Lots of different perspectives when it comes to shock tuning.

 

the issue with increasing free bleed is it is bi-directional and effects the rebound side of the stroke as well. Not that this is necessarily an issue on all applications but it can change more ride characteristics than what you’re trying to focus on. Free bleed also decreases the low speed control which is essential for slower crawling.

A bypass is absolutely a good solution for this issue but as stated requires an additional shock and has other down falls.

 

I love reading all the different perspectives, I’m here to learn. Keep the discussion going

Shock tuning is a new science to me. I plan on doing my own revalves once I get my front kit together. Seems simple enough

 

If you have ever seen a shock dyno graph (for a linear valved shock) it looks like a straight line . With the Y axis as force and the x axis as shaft velocity. That straight line cannot be extended out to infinity…(you can’t keep adding thicker and thicker shims and expect it to behave linearly ). There is actually a specific region in that graph where it behaves linearly. By adding more or less shims you can make that line more or less steeper , with in that range. This is the key point and point I’m trying to make …. Outside that zone it is the main working pistons’ ports which set the upper and lower limits where that “linear zone” is .

there is a reason race teams make their own custom shock pistons. There is a reason trophy trucks don’t run cantilever shocks in the rear ( motion ratios ! Shaft speeds for that weight / shock combo )…. And again , there’s a reason I-beam shock tuning is easier than a 8” travel shock on our LT a arm trucks (despite being capable of 14”+ travel).


In theory , you can even get a 1” travel shock to work but it won’t be a simple as “just revalve it bro with sum thicker shims” .


This is not road car racing where there is essentially one driving style / shaft speed the shocks will see. In off roading at speed you have a very wide range of situations where the shocks will need to move fast or slow and respond accordingly . That response is not linear and goes beyond simple valving

you want ur LT a arms to work way better ? Cut out that coil bucket , install at least a 10” shock further out on the a arm so it sees higher shaft speeds …alternatively, keep your 8” shock fire up your cnc machine and custom make a new piston to accommodate. which is more practical and accessible to most people ? . You’re welcome

 

Or just pull out the compression valving out of your shocks, take a test drive around some where with the kind of chop and nuisance rocks you want tuned out and if it's still too rough there's nothing that can be done with the current springs on the vehicle and those need to be dealt with before even bothering with tuning the valving.

 

Being new to LT, some of your comments got me not sure if serious or joking.