Help me decide between 14" or 16" coilovers

GearHead11

Well-Known Member
Joined
Jul 10, 2013
Location
Winston Salem
Looking at linking my truck and am trying to decide between 14's or 16's. I've been speaking with Ryan at Accutune and he was saying that since 16's need longer springs you have to go with a lighter rate resulting in some body roll whereas there are more spring rate choices with 14's so you can go with a firmer spring (if I understood him correctly). I'm shooting for a 25-26" frame height with 5-6" of uptravel. I primarily crawl so I would like the extra travel of the 16's but I'd like to be able to be stable and go fast when I want as well.

Coilovers are a completely new topic to me so I'm learning as I go but there's tons of knowledgable people on here and I'd like to hear what you have to say.
 
My only reservation with 14's is I wheeled with a guy who had 14's and a 4wu kit at URE and I really wasn't impressed with the travel he was getting when he flexed on poser rock.

On the other hand, my reservation with 16's is since I'd have to go with lighter springs I'm worried it might be a bit slinky like with my inboarded 63's.
 
Remember with 16s you need a 18" lower spring to be politically correct. A 14" CO you need a 16" lower spring. There's no law that states this outside of Pirate. Take that with a grain of salt. Unless you're in a full tube chassis buggy with no body panels and can lift any tire 60+" off the ground it's a waste of money. Go 14.
My 6.0 buggy on 42s had 16" Foxes F/R and barely used 13" of travel on either corner. Pics speak volume.
IMG_20150403_220409920_zpsjejhuomf.jpg
 
GearHead11 said:
My only reservation with 14's is I wheeled with a guy who had 14's and a 4wu kit at URE and I really wasn't impressed with the travel he was getting when he flexed on poser rock.

On the other hand, my reservation with 16's is since I'd have to go with lighter springs I'm worried it might be a bit slinky like with my inboarded 63's.
Click to expand...

I would be after more usable travel rather than a ramp champ.
 
This is a buddies truck that has me wanting to run 16's. His truck works really well. Granted he's on beat 37's and with me running 40's I may not need the extra droop since my tires would reach down just as far on a shorter coilover..

Nate Tacoma.jpg
 
Nate tacoma 1.jpg


Like I said, this is uncharted territory for me so I'm just going off of quality builds that I know of.
 
I know. He's at 21" to the frame too and still has 6" of up. He had to notch the bracing under the hood to clear the hoops
 
Chris_Keziah said:
14's, I doubt you would ever use the full travel on a 16" up front. For the rear suspension you could go 16's but I wouldn't for the front.
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This. Your front is climbing the obstacle, vast majority of the time you don't need all 14" of travel much less 16". I would definetly do it in the rear as the longer you have tires on the ground the more it's going to help get the vehicle up the obstacle.
 
You need the length travel shocks that are slightly longer than the amount of travel that the suspension is capable of.

How much misalignment can the steering take?

How much pinion angle change is allowable at what amount of travel?

How much travel before your a/s values go haywire?

These are all design points that will affect the travel amount greater than the length of the shocks.

You want slightly longer shocks than what is useable, so that you can bumpstop and limit strap the shocks before bottoming and fully extending the shock.


As far as springs, take a look at what's available. These are just the common rates from PAC. Check their site for specifics.

16 in rates are very similar to the available 18 in rates.

auploads.tapatalk_cdn.com_20160324_e1425e968c6f66641ee9b9e441dedd43.jpg


auploads.tapatalk_cdn.com_20160324_07ce85122aa0cb76474d31c81f8f713f.jpg


You want a 2" longer main spring than the shock travel amount so that at full droop, the dual rate slider stays completely on the shock body.

Some people flip the slider over with shorter springs, but this can crack the slider when adjusting the dual rate slider stop as a means of controlling body roll and the step up rate.

The slider is designed for the short end up.

With fox and king, and 2" longer main spring, the secondary spring is the same length as the travel amount.

Swayaways are shorter and require a 2" shorter than shock travel secondary spring, while using a 2" longer main spring.

My point is, spring selection is a good point to picking shock travel, but is secondary to amount of available travel due to steering or driveshaft bind.

Here is the link my spring rate calculator for when the time comes. Thanks to @ol'Jeeps for hosting. [emoji106]
http://metalwerxdesign.com/files/springcalculatorv2.xlsx
 
That's a lot to process but I think I'm following. Steering will not be a limiting factor as I am full hydro. I do not have the other numbers because it's not linked yet. My plan was to buy everything I will need before I start cutting
 
Mac5005 said:
You need the length travel shocks that are slightly longer than the amount of travel that the suspension is capable of.

How much misalignment can the steering take?

How much pinion angle change is allowable at what amount of travel?

How much travel before your a/s values go haywire?

These are all design points that will affect the travel amount greater than the length of the shocks.

You want slightly longer shocks than what is useable, so that you can bumpstop and limit strap the shocks before bottoming and fully extending the shock.


As far as springs, take a look at what's available. These are just the common rates from PAC. Check their site for specifics.

16 in rates are very similar to the available 18 in rates.

View attachment 213531

View attachment 213532

You want a 2" longer main spring than the shock travel amount so that at full droop, the dual rate slider stays completely on the shock body.

Some people flip the slider over with shorter springs, but this can crack the slider when adjusting the dual rate slider stop as a means of controlling body roll and the step up rate.

The slider is designed for the short end up.

With fox and king, and 2" longer main spring, the secondary spring is the same length as the travel amount.

Swayaways are shorter and require a 2" shorter than shock travel secondary spring, while using a 2" longer main spring.

My point is, spring selection is a good point to picking shock travel, but is secondary to amount of available travel due to steering or driveshaft bind.

Here is the link my spring rate calculator for when the time comes. Thanks to @ol'Jeeps for hosting. [emoji106]
http://metalwerxdesign.com/files/springcalculatorv2.xlsx
Click to expand...
He's right he was paying attention when i was just having fun lol i have 14s and can use all of it but 16 would be to much I have never been in a situation where I thought more down travel would have got me to the top of the hill coilovers make going fast a lot more fun
 
GearHead11 said:
View attachment 213530

Like I said, this is uncharted territory for me so I'm just going off of quality builds that I know of.
Click to expand...
The times we've talked and you never asked the coil over questions...tsk tsk.[emoji41]

Looks like your friends coilover is hitting the frame and bowing the shock on full droop...but it may just be the pic.
 
Also, don't let the soft springs of either size shock scare you too much. Much of the body roll can be tuned out in the shocks, as well as setting up the geometry of the links to combat body roll. Also, don't discount the use of a sway bar, they're not just used to combat sway but also to tune the opposite end of the trucks suspension to do more work...
 
mcutler said:
The times we've talked and you never asked the coil over questions...tsk tsk.[emoji41]

Looks like your friends coilover is hitting the frame and bowing the shock on full droop...but it may just be the pic.
Click to expand...

Haha was just tossing around the idea of linking but im set on doing it now so I'm trying to ask the right questions.

mcutler said:
Here's some reading for you,

the spring tech thread - Pirate4x4.Com : 4x4 and Off-Road Forum

Geometry. My post KOH bi annual suspension thread. - Pirate4x4.Com : 4x4 and Off-Road Forum

Suspension geometry for GETIN IT! - Pirate4x4.Com : 4x4 and Off-Road Forum

Settle in, have a coke and a smile, and eat some brain food...

Call me if I can help.
Click to expand...

Looks like I've got something to do on my day off tomorrow. I'll give you a call when I get through all that, thanks!
 
Got on the ramp at Gulches yesterday. I'm pulling pretty good travel on leaf springs already so I think I'm going to stick with 14's considering my 14's in the front aren't even fully extended here

awww_tacomaworld_com_media_img_20160326_105710268_510046_full_e7b788536b28f1921245f08734929b0d._.jpg
 
Just catching up on this thread.

I agree that 14's are the right size for the front of your Tacoma. (As you've chosen).

If you run 5" of up travel, a 14" travel shock gives you 9" of droop, which is a lot. With a 16" travel shock you have 11" of droop, that's more droop travel than some rigs have as total travel. It works well for a lot of people, but I also think it's not really necessary.

When you start to run 7" or more of up travel a 16" travel shock starts to make more sense.

If we stick with the 1" preload rule in the front (which has been a good rule of thumb for a long time), your spring rate has to be drastically softer to maintain preload with 2" of extra droop. With 14's you'll run 150/200, with 16's it would be 125/150.

The reduction from 200 to a 150 lower is a 25% softer spring rate. In addition, we will valve rebound softer to accommodate the lower spring rate.

As we can see, more droop = more body roll.

Here is an article I wrote about this subject: Shock & Spring Selection For Off-Road Handling Without Sway Bars
 
Start cutting and order a Barnes kit, Build it at full bump and go from there. Keep a 4/3 link calculator handy if your not comfortable with link setup. 1 inch to and fro made a noticable difference. o_O


My vote is for 14s... Articulation is a double edged sword...easy to get yourself in more trouble then it's worth,
 
I ordered 14's. I'm thinking about going with a 4 wheel underground kit. The geometry is done and all I have to do is locate the brackets. Would make it very easy and keep downtime minimal as wheeling season is ramping up. Debating on ordering a full width diamond while I'm at it..
 
Yes and yes, a buddy of mine has the 4WU kit on his Toyota and the whole kit is tits. He said it was really easy to set up and everything fit perfect first time.
 
TRD said:
As we can see, more droop = more body roll.

Here is an article I wrote about this subject: Shock & Spring Selection For Off-Road Handling Without Sway Bars
Click to expand...

In that article, some very misleading wording jumped out at me.

"...in the example below, going from 2″ of preload to 1/2″ of preload resulted in a 19% increase in spring rate."

Changing the springs is what increased the spring rate. Preload does not change spring rate; preload is just preload. A spring with a rate of 100lb/in (for example) and 1/2 inch of preload still has a spring rate of 100lb/in. You just have to overcome that initial 50 lb. preload amount to get the spring to travel, and then you still have a 100 lb/in spring rate. So it only shifts the force versus travel line (linear spring rate), it doesn't change the slope of that line (which would mean a change in rate).

I know you know this already, but the wording killed me...
 
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Fabrik8 said:
Changing the springs is what increased the spring rate. Preload does not change spring rate; preload is just preload.
Click to expand...

Preload is tied to droop travel and spring rate. If you change preload and leave droop travel alone, then your spring rate must change. So by increasing preload you end up with a 19% lower spring rate (in the example).

I'm happy to change the wording, but not really sure how else to say that more concisely, or more clearly.
 
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