Stock height rear shock length

[perry]

24.5” eye to eye On rear, 2012 screw, stock suspension

 

[fitzmotor]

Perry, Thank you very much, that is the info I needed, now I can go about setting the shock up.

With 23.75 being the shock travel center, that means Ford (if I have my measurements correct) set the shock travel up for 6.4" compression and 4.9" rebound, 11.3" total, (that's shock travel) the overall suspension travel has the 12.1", which would be 6.8 compression and 5.3 rebound/droop, that makes sense.

If anybody has any info that I flubbed up my numbers, please chime in, I'd rater be wrong than believe wrong info.



Thanks again.

 

[Christyle]

What does the static piston location on a normal shock have to do with it's ride quality? Your shock is built for your application. You won't bottom out your shock if you have your factory bumpstops still in place, regardless of where the suspension has sagged/been modified to. If you installed lift springs, that would be different, as you're almost out of extension at ride height. By cutting your shock shaft, you're guaranteeing that you will now top out your shock on certain road conditions, unless you've installed something to limit the droop. Hardly any application is set for perfectly equal compression/extension. If you were really going to be taking such a drastic step as cutting and re-threading a shock shaft, why would you not be actually taking cycling measurements of the springs, shocks and bumpstops as a SYSTEM, rather than just cutting a shock shaft because you think your truck is lowered? Asking for information from random people on the internet for such an important step seems like something I would CERTAINLY be doing myself.

Additionally, going through the hassle of cutting and re-threading the shock is pointless on this application unless you know where the internal bypass holes are, as you may end up setting your static piston location incorrectly, and making things worse.

 

[fitzmotor]

Thanks for your input, a bit abrasive, but forgive me I'm just a old gear head who overthinks things, to me it's simple, lower truck, shorter shock, that's all.
To me shock rework is also simple, nothing drastic really, not for me, but I take stuff apart and rebuild it for a living.
In the racing world for example, (no I'm not racing my truck) if you make a change to a chassis, you make sure all the relating parts are reset to match.
Sorry to have this post go the way it did, I tend to get overly technical, to a fault.

Thanks

 

[Christyle]

And I tend to be an *******, to a fault.... I cut my forum teeth on some rough and unforgiving boards, so I tend to revert back to it from time to time on unsuspecting victims.

Your scenario is correct, but not the way you'd like to apply it here, I think. Did you lower your truck, or do you think it's lowered? To know how to adjust the rest of the factors, you need to know what the initial change was. I'd use the ride height measurements given by MTF as your baseline of where you should likely be. Look at what springs you have (factory with a block?) Is your bumpstop the factory kind? Also, if you only shorten the shaft when your suspension has been modified, you'll still have the same issue of bottoming, but instead, it will be the end of the shock body on the eyelet of the shock. The piston bottoming and the body-eyelet bottoming cant be too far apart, so just fixing one may not solve your problem.

 

[fitzmotor]

I have considered all the things mentioned, I am 2" lower than MTF, my truck is level.

I should have posted my question differently, like I just wanted to get back to stock, I bet I would have got more positive info.

I really appreciate the helpful info, I didn't expect the all the other info, but I should have thought it through.

The Raptor is a fantastic truck, I love mine, I understand the loyalty towards it, you cant imagine how many times I've heard "YOU LOWERED A RAPTOR"

I should have been mindful of the people who wouldn't get what I'm doing, I am a fabricator by nature, I build all sorts of heavily modified stuff, you should see my 75 F350 Screw, or my 65 Mustang, even my ebike, I cant leave anything alone and after 20 yrs in the racing industry I just cut, chop, modify, machine up anything needed, just like you would on a racecar.

So please accept my apology if I came across sounding insensitive to the design intent of the Raptor.

 

[Christyle]

I don't care how you modify your raptor, that's your choice, I just didnt understand the method you were choosing to achieve it, and was trying to keep you from making a costly mistake. The shocks on a raptor aren't normal, they have internal bypass holes, so it's just a little different than your average shock, as the static resting point of your piston and the amount of the travel you plan to use has a large impact on the way the shock operates. Plenty of people buy a raptor for the looks and not for the functionality, so adjusting the intended use of the truck isn't new, so no offense taken there.

 

[fitzmotor]

The purpose of shortening the shock shaft would be to put the shock piston back in it's original location, the proper location in relation to the bypass holes, that is the whole object of this like I stated originally.

It's the only thing that matters to the shock performance, the travel will indeed affect the suspension performance, but only when when you run out of travel.

If it was a concrete queen you could have a 6" travel shock, and if the piston were in the proper location, it would perform just like 12" travel shock, until you ran out of travel.

I know I'm being redundant here , but it seems like it's a point that's getting lost.

As for cost, I have 2 shafts that have rock dings down at the very end of the shaft, the guys at Forged Offroad sent them to me for free, I just had to pay $20 shipping.
The dinged area will get cut off. As a note, they also cut shock shafts to suit a given application, it's not really a big deal.

 

[fitzmotor]

The info back from Fox was the shock will operate between 60/40% or 40/60% compression/rebound.
That translates to a minimum installed length of 22.6 eye to eye shock length 40% comp, 60% rebound.
And a maximum installed length of 24.9 eye to eye for 60% comp and 40% rebound.
The shock specs are 29.5 extended, 18.0 collapsed with 11.5 travel, all this is if I have done my math correctly.
The email from Fox made it seem like specs were not as critical as I was thinking.
So my starting point of 21.0 was indeed too low, I am more after the 24.9 length, which I think I can achieve without cutting the shock shaft, I made a top mount extender which gave me 2.0 higher mounting, now I have to lower the bottom mount just under 2.0 and I will be good.
I have gotten away from the shock shortening idea, it will be easier to replace them without having to machine everything, and being able to buy new rears for $350ish each, it's a no brainer.
Here's the upper mount, I should do a drop one for the guys who lift them.