Split ring adjusters on Coilovers

This recently came up, so I thought I would start a dedicated thread about it. I really think the manufacturers of coilover systems need to be called out on this. Nearly every manufacturer of these systems has now gone to a single split ring preload adjuster utilizing a pinch bolt lock. In the past, at least Fox used a two ring system: one solid adjuster ring and one lock ring. Now they have abandoned that simple and effective design too. Even OME, who I generally respect for their good engineering, is using this crap split ring system.

I can only presume that they have done this to save 2 or 3 bucks on systems that sell for $1,500 or more! In the process, they have created massive problems with the adjustment process, and damage to countless shock bodies.

The problem is that when the pinch bolt is loosened, the threads expand and become loose on the shock body. If the ring is just expanded a couple of thousandths of an inch, then the ring can move without danger of stripping the threads. Any more than that, and the diminished thread engagement puts the system at risk of stripping, or complete failure. With the load on these rings, knowing how much is too much is impossible. Adding to this problem is the fact the sharp edge of the split in the ring becomes a cutting surface, much like a thread cutting die. A quick search of the interwebs shows that hundreds (maybe more) have stripped their shock bodies trying to adjust a coilover that is sold as "adjustable".

Sounds like a huge warranty problem right??? WRONG! The answer that these manufactures have devised to sidestep responsibility for this abomination of engineering design, is to stipulate in the fine print that NOW the units are only truly "adjustable" when removed from the vehicle with the springs held by a spring compressor! How the hell does that qualify as "adjustable"??? The job of preload tuning, that used to take minutes on the truck, with nothing but a spanner, now stretches into many hours, and requires tools that few people have. For what?? Saving that couple of bucks?? Sure, lots of people take the risk and just adjust them on the truck, but you have to be very careful not to over loosen that bolt! If you somehow misjudge, or simply just have no idea of the risk you are taking, then you just trashed a $1,500 coilover, with NO warranty recourse. This is criminal.

There are only two ways to make these adjusters correctly:

1. Most obvious is to go back to using two simple rings, and add the 2 bucks to my cost if you really have to have it.

2. Make a very beefy split ring with a tapered cut at the split interface to prevent gouging the threads, and build a limiter into the ring so that it cannot expand beyond the minimum diameter that would allow for moving the ring. It should be completely safe to remove the pinch bolt entirely. The ONLY function of the pinch bolt should be to lock the ring. Nothing else!

I took the time to write this because this crappy practice really needs a light shined on it. If we just accept this junk, we are part of the problem. Fox has told me that the solid rings are no longer available. A very long search turned up a supply of them at Poly Performance. Until these manufacturers step up and fix this, the best we can do is replace these rings at our expense. I have no idea how many of these PP has, or if they can get more. Fox denies that they exist. I have two sets hidden away just in case they do actually disappear. I think King uses the same ring, but PP can probably help confirm fitment on other units.

Also of note is that the new OME system appears to use a finer thread on their bodies. I don't know of any source for a solid ring for their shock body. Frankly, I would love to try their BP-51 system, but no way am I forking over money for that problem. They need to make that right first.

Here is the link for anyone interested in the solid rings: https://www.polyperformance.com/fox-2-5-coilover-shock-preload-ring-234-00-233-c

My experience with Poly Performance has been very good. Hope this prevents someone else falling victim!

EDIT: installation of the double ring system does require you to disassemble the shock. Not a great design either.

 

bump for useful info

 

Great info..........had no idea.

 

Except apparently some coil overs use neither.

J

 

Having nearly slipped my own lock ring on my foxes, I agree!!!!

 

Nice too know the faults of this design.

 

So as long as you don't try to adjust your coilovers your shocks should be fine.

 

Never had issues on my Foxes or Kings while adjusting the split collars while it was on the truck

 

Split rings have always worked nicely for me, no galled threads and no stuck rings. Theyre performance car/truck parts so you have to use your own common sense to adjust them. And the aluminum ring isn't cutting threads on steel and aluminized steel threaded shock bodies cause you know... Material hardness and other pesky physics principles. Hey since we're analyzing tiny differences like they were what sunk the Titanic. Why can't you check ATF with a dipstick on new Tacomas?!

 

Probably same reason why the Tacoma doesn't have rear disc or power seats.

 

Do people actually like power seats, every vehicle Ive had them in made me want manual. Power is slow. I just wanna reach the back for a minute not wait for my seat to load.

 

So your saying the O.p didnt adjust his correctly ?

 

He's absolutely right that if you loosen a split ring too much with coil tension on it that it will jump. But they also adjust nicely if loosened just a tiny bit. Chances are he loosened it too much because he wasn't attune to how much force it can take to turn them with weight on them (can take quite a bit).

 

Makes sense

 

Never had any issues. I’ve had both as well.


Likely user error.

 

The point is, coil over adjustment should be a zero fail proposition. It should not take a master tech or an engineer to understand how wrong this can go. The pinch bolt can feel very snug, but that is because the adjuster ring is under intense pressure. When I adjusted mine, I found that I could not judge how much the adjuster ring had been loosened, and I am an experienced mechanic, and a mechanical engineer. I had to take the unit off the truck and find the lock point with pressure off the ring. Then I only loosened the pinch bolt 1/4 turn to adjust the ring.

Whether one person gets away with making an adjustment, or suffers a failure has nothing to do with the FACT that this is a very poor design, that has been substituted for a PERFECT design to save a couple of bucks. Two solid rings, one larger adjusting ring and one smaller locking ring is far stronger, and will NEVER jump a thread. ANYONE can adjust it, on the truck, without a $750 spring compressor. The double rings also give the seat much more strength in actual use too.

The people who haven't had issues with these adjusters are far more lucky than skilled. When THEY have the problem, THEN it will be a design issue. Till then, is someone else's problem. People who have issues most likely did not have the bolt tight enough. That is true, but they also most likely had every reason to believe it WAS tight enough. This crappy design is a trap that people will continue to fall into, for absolutely no good reason.

 

You are getting two threads mixed up. I did not have a failure because I realized the problem as soon as I looked at it. I took measures to make sure it didn't happen. This thread is just to inform people, hopefully to keep them from experiencing a failure. In a perfect world it might even lead to changing the way these systems are designed. That won't happen with just one voice.

There is another thread that just started with a guy who has the problem I am trying to warn people about. His are King coilovers. I guess we will see how his claim goes.

 

I've only had dual ring setups on my race car.

While I understand how a split ring can/should work, and needs to be cared for, I'd much prefer a dual ring. Less fidgety to deal with at the track.

I'm sure most truck users (other than actual race trucks) are more the set it and forget it type. Maybe a few tweaks during early days of ownership to hit a personal sweet spot and they are done.

I'd even go so far as to bet a huge number of installs are done in a shop, set in a shop to some pre recommended position and never touched again. Meaning it doesn't really matter to those owners.

But overall, I agree with @badger

I'd gladly pay a couple extra bucks to have dual rings.

 

When racing cars, trucks or motorcycles suspension will always change from track to track and rider to rider.
Suspension in racing is huge and can cause you to be the fastest guy or the slowest guy. In my opinion if you
aren't racing for money or a championship set your suspension at the height you want or need and let it be. No
reason to be adjusting these shocks like the pros do between races.

 

Consider this:

"Class of fit" is an engineering term that describes how well threaded components fit together. Generally they fall into 3 classes (1, 2, and 3). Class one is a very precise fit for things like focusing adjusters or other very fine tolerance items. It is also a high strength engagement. Class 2 is generally used on good quality fasteners. It provides ease of assembly while retaining adequate strength. Class 3 is a very sloppy fit that is only used in applications where neither strength nor precision are required. A loose thread is VERY weak!! The difference for instance between a class 1 and a class 3 thread on a 3/4-10 bolt is just .0069". Class 1 to 2 is just .003". On a 2 1/2-12 thread, the maximum pitch diameter tolerance is .0082 for a class 2 fit

Now consider the pinch bolt scenario: If the bolt used to pinch the ring is a 1/4-20, then each revolution of the pinch bolt is .050". That translates to .016" at the pitch diameter of the shock body. That means that one half turn of the pinch bolt takes you from tight (locked) to a class 2 fit, which is probably the minimum that can support that load safely. Any more than that and you are in dangerous territory! That is how sensitive this is!

This can cause a failure the very first time you try to adjust it.