Wednesday, January 7, 2015

Informational Series Part 3.2 Rack Spacers (Angle Spacers)

Welcome to chapter 2 of part 3.  If you haven't read chapter 1 yet please do so before reading this chapter.  There is some vital information that will need to be understood in order for this chapter to fully make sense.  Here's a link for chapter 1:

Now that you've read that, it's time to continue on with where I left off and begin spreading the knowledge of rack angle spacers (both slip on and bolt on) how they work, what they can do for you, and what things they will change.

Chapter 2 starts now! Lets begin!

If you're a drifter, know a drifter, seen videos of drifting, or maybe just saw a picture of a drift car.  Surly you've noticed how much steering angle a drift car has.  When drivers were new to the sport or maybe you're just starting out you've probably tried looking up how to get more angle out of your stock steering setup.  Upon that search you more than likely discovered rack angle spacers and saw a pic of a tiny little 5-7mm thick ring.  I'm sure you probably saw that and thought, "what in the world is this for and how does this give me more angle?"  Heck I'm sure some people might have even questioned if it gives you more angle at all.  Rest assured, they do work, and you do get more angle from them.  There are a lot of factors that go into how much they add but just know, a spacer will almost always give you more steering angle.

If you actually read chapter 1 like I told you to before reading this and you paid attention to what it said, then you found out all about how a steering rack works to turn the wheels.  This is something you will need to know and understand in order to learn about how rack angle spacers work.  The first ones I will be talking about are the basic slip on spacers.

A slip on rack angle spacer is the cheapest and most simplistic thing you can do to add more steering angle to any car that uses a steering rack.  In fact this is my number one recommended modification for drifting.  I strongly urge everyone out there to utilize an angle spacer because they do make a lovely difference.  A lot of modified and aftermarket steering knuckles are designed to work with an angle spacer in order to get the maximum amount of steering angle.  So yes, even you guys with modded or aftermarket knuckles you should be using these if you want the max amount of angle.

How a spacer works is simple.  For a slip on one it will be installed on your inner tie rod where it bolts onto the rack.  This will in turn work like an extension to the rack and give it the ability to travel farther.  More rack travel means you can turn the wheel more, the more you turn your wheel the more steering angle you get.  It's as easy as that.

Here's a picture of what slip on rack angle spacers look like.

Just unbolt your inner tie rods, slap these on over the threads like you would a washer and bolt your tie rods back on the rack.  I recommend using some thread locker while you're at it too since you'll need to remove the metal locking clips and not as much of the tie rod will be threaded into the rack anymore.  Then all you have to do is re align the front otherwise your wheels will be toed in on a rear steer car and on a front steer it would be toed out and you're good to go!

In the above example you can see what an angle spacer would look like once installed.  Sitting on the end of the rack

Here's another example of rack angle spacers installed on a rack. In this one you can see the amount of extra amount they add to a steering rack.  Now lets take a closer look at what they do when turning.

Lets start with the top two in this pic. Both racks are set straight, the top one is without spacers and the bottom one is with spacers.  With the spacers on the rack you'll notice the inner tie rods sit out farther, so what you need to do when installing these is thread your outer tie rods on farther so they sit in the right position with your wheels straight.  In the example you can see the outer tie rod pivots (the outer circle coloured in purple) line up between both racks because the outer tie rods on the rack with spacers were threaded in farther.

Now lets focus on the bottom three.  Turning the racks left you'll notice the one without spacers stops where the rack ends, the inner tie rod being the stopping point preventing it from traveling any farther.  The second one down you'll see when turning the wheel the same amount the rack angle spacer provides it with more room to travel.  Notice how the outer tie rod pivot points are aligned at this point.  Both were even when straight so when turned the same amount they remained even with each other.  Then we have the bottom rack, this one was turned even farther thanks to the angle spacer which fits inside the casing and acts as an extension to the rack.  This is where you see the added travel in action.  The outer tie rods have now traveled a farther distance, I've drawn some comparison lines to show this.  However big the spacer is will determine how much extra travel the rack will have.  The more travel you have the more you will be able to turn your wheel and get more angle from your steering.  One thing to point out, is that there is a limit to how much you can add.  There are only so many teeth ground into a rack and at some point when turning there won't be any more teeth and the pinion gear will jam on the rack itself.  Thankfully for the S-Chassis and some other cars this isn't an issue as from the factory the amount of additional teeth in the rack are enough to allow for a lot more travel.  I don't know the exact amount but I believe it's somewhere in the 20mm range.

Time for the downsides to slip on angle spacers.  For starters the threads on inner tie rods are only so long, so this means you can only make the spacers so thick.  The thickest ones I've seen on the market are 7mm and that doesn't leave a whole lot of thread left on the tie rods so I wouldn't go anything past that or you could risk having too few of threads holding your tie rods on and risk stripping out your steering rack having the tie rod pull out of it.  So that's one downside, but thankfully companies have started to catch onto this, some tie rod makers are now putting longer threads on them to compensate for this, others have even started making tie rods that have a built in angle spacer to them.

Here you can see an example of some tie rods that offer built in angle spacers vs factory tie rods.  At this point if you happen to have a pair of these you could add a slip on spacer as well to get double the amount of extra travel.  Of course this sort of thing won't work with all setups.  Almost every aftermarket knuckle will run into the bump stop well before you would use that much travel so don't think you can take your 65 degree steering angle setup and slap a pair of extra spacers on there to get more lock.

Then we have downside number 2.  This one is an interesting one, it can be bad and it can be good.  It really depends on the car and the setup as a whole.  These do effect bump steer, its a very very small amount with just a slip on spacer but it is there.  However with knuckles that move the arms location out, that would make corrections to the bump steer changes the spacers made.  So as you can see, it can be bad or it can be good.  Either way, a small slip on spacers change is so little you won't even notice it.  Especially if you're running a heavy spring and don't have a lot of front suspension travel, as you need to have travel in your suspension to have bump steer.  The other thing to note about it, is the bump steer change it makes adds toe out.  This means as you hit a bump the wheels will toe out with suspension travel.

Lets talk about bolt on angle spacers now.  These work in the exact same way as a slip on spacer (giving the rack more travel) however with the bolt on ones you will actually bolt a machined spacer onto the end of your rack and then your tie rod will bolt onto the other end of that spacer.  These spacers offer much more travel than a slip on spacer.  The one pictured above is equivalent to running a double spacer setup.  Majority of bolt on spacers come with one machined spacer that bolts onto the rack (usually meant to be installed on the passenger side) and one slip on spacer that's to be installed on the opposite side of the rack.  There are also some other ones out there I've seen for different cars that put a bolt on spacer on both sides of the rack.

For the one above, its a single sided bolt on, and at this point you've probably noticed that the spacers aren't exactly equal in length. It's true, they aren't equal length, the bolt on spacer is 3 times the spacer thickness as the slip on one.  So when installing these the rack will need to be re centered.  This will leave your steering wheel crooked, so you'll have an extra step of having to unbolt your steering wheel clock it however many degrees you need and bolt it back on center.  You NEED to do this if you want your steering wheel to be straight when the rack is centered.  Otherwise one of two things will happen, the first one being you'll have to drive with a crooked steering wheel, the second being if you get an alignment with your wheel straight you'll have more steering travel on the one side so your turning will be off balance and your bump steer will also be off balance between the two sides.  Either way those will both have an effect on your driving and make you suck, so make sure you center your rack and center your steering wheel with it!!! 

Here we have a nice little comparison going on.  No spacer, slip on spacer, and bolt on spacer.  With this one you can really start to see the difference that angle spacers can make and what the differences look like between the two angle spacers.  Keep in mind, none of these drawings are to scale.  Something you'll notice is the change in tie rod length, as you add more to the rack with the spacers the tie rods become shorter.  If you turned all three of these racks the same amount of turns all three would be at the same position, then with the slip on spacer you'll get another tooth, and with the bolt on spacer you'll get two more teeth.  I marked an area with two red arrows.  You'll notice the bolt on spacer rack has been re centered, when straight it has 4 open teeth it can turn left where as the other two only have 3.  Then at full turn the rack without a spacer traveled 2 teeth distance, the one with slip on spacers traveled 3 teeth distance, and the one with the bolt on spacer traveled 4 teeth distance.  This same thing would be true when turning right.

As you can see, the same amount of travel is achieved (I didn't draw the teeth on the rack even from side to side so ignore how sloppy it looks >.<).  If you look at the outer tie rods you'll notice the difference in travel is the same as the example of turning left.  So you can see that no matter what way you turn as long as you center the rack with the bolt on spacer it'll have the same amount of travel turning both directions even though the bolt on spacer is three times the size of the slip on spacer that's install on the opposite side.

Now once again, it is time for the downsides.  A bolt on spacer isn't as forgiving with it's downsides as a slip on one is.  A bolt on effects the bump steer a lot more than a slip on one.  They have over double the effect, so at this point you're going to start to notice the change.  This of course is bump out.  There is some hope however, it's not a perfect solution but it is a commonly used fix.  Bump steer adjustable outer tie rods.  I will talk more about these in a later post but for now I will leave you with this.  On the S-Chassis and many other cars if you adjust the outer tie rod down a little it'll reduce your bump out under suspension compression, possibly reducing it enough that you won't be able to notice it that much.  Like I said, I'll talk about this in a later post and I'll explain how and why when the time comes.

I personally have put a bolt on spacer on a car before.  In fact, the one pictured above is the exact spacer I had installed.  This one was put on my girlfriends old car as it's a very inexpensive way to add a lot more angle without needing to make any modifications other than cut a little length off your inner tie rods and possibly grind down a bump stop.  They worked great on her car, and they have worked good for many other people.  They just have that bump out problem, if you keep your stock outers on the car it's something you will notice although it's still something that can be drifted on without too much issue, so don't let this downside discourage you if this is something you're interested in.  Try it out for yourself and see if it's something you are able to work with.  If you've got too much bump steer going on and find your car feeling like it's understeering you can always nab up some outer tie rods to make some adjustments to help with the issue.

Another thing to note, that might not effect everyone, is that with stock knuckles you'll find you more than likely will have to grind down your bump stops.  With this it's possible you might run into an over centering issue.  I've seen this happen before, so if you're installing these and find you need to grind down your bump stop in order to fully utilize the added angle these can achieve, do it a little at a time to make sure you wont have an over centering issue!

Moving on now, lets talk about downside number 2.  This one doesn't apply to all bolt on spacers as some of them get installed on both sides of the rack.  However for the S-Chassis style ones, that's not the case.  Only one side gets bolted on.  When this is the case after you center your rack your inner tie rod pivots will not be centered as the bolt on spacer will have some extra material on it for you to put a wrench on and to provide some area for the inner tie rod to thread into.  This added material will effect the bump out more on that side then it will on the other side.  This will make for an unbalanced bump steer setup so when turning one direction you might feel more of the effect than turning the other direction.  If you look closely at the drawings of the bolt on spacers you'll be able to see that the inner tie rod that's on the same side as the bolt on spacer is slightly shorter and the inner tie rod pivot point sits out farther.

I hope this helped everyone learn and understand how rack angle spacers work and the differences they can make.  Now we can move on to the final chapter of part 3!

Happy readings and I'll see you next post!

No comments:

Post a Comment