Alright here is the deal. I have read alot of archived threads about caster/suspension theory. But there seems to be no general consensus regarding caster's affect on tramlining. Many argue that adding positive caster (say by swapping the uca's on a dc2 and going from 1.0 degree to roughly 3.0 degrees positive) decreases the amount of tramlining. The argument is that increased positive camber promotes self-centering, thus the vehicle is less affected by uneven or rutted road conditions. Is this true?

I am aware that there are many factors that lead to tramlining, such as tire selection and bushing condition. But will adding 2.0-2.5 degrees of caster noticeably reduce my dc2's tendency to follow the longitudinal ruts and/or grooves in the road?

Thanks is advance! And sorry for my low level of intelligence.
-Conlan

 

Well swaping the UCAs was actually tested on an integra before in another H-T thread (sorry I don't have link). It turned out that bump-steer was significantly increased, and that is wasn't really worth the added caster...

As for your tramlining question, I can't really say...

 

So are bumpsteer and tramlining related? Or are they two seperate problems?

I found this...

BUMPSTEER causes your steering wheel to turn slightly as your front suspension cycles up and down, as when the car goes over a bump, or when the body rolls in a corner, or when the front end dives during heavy braking. This "self steering" happens because the tie rods and control arms are moving in different arcs. Instead of tracking with the lower control arm, the tie rod pushes or pulls the steering arm as the suspension goes up or down. That changes the steering angle of the wheel and makes the car respond exactly as if the steering wheel had been turned by a small amount.

TRAMLINING causes your front tires to follow ruts or longitudinal cracks in the road surface, forcing you to fight the steering wheel to keep the car going in the direction you wish. Tramlining is related to tire size and tread design. Some tires tramline very badly, and others not at all. High-performance, wide, low profile tires are often the worst. Tramlining can be reduced or eliminated by changing to a different tire design.

 

Not really related (as far as I know). The explinations you've posted are accurate (in my experience)...

 

Here is the link to the same thread in the Road Racing/Autocross Forum: (I just wanted a slightly different perspective)

https://honda-tech.com/zeropost...99121

A few have experienced reduced Tramlining from increasing caster. Any more?

 

Well, the results are in, but here is a little background info first... I swapped the UCA's this morning and took her in for an alignment. I took a look at my alignment specs from last week to see what my caster looked like before today's alignment. The driver side was -0.23, the pass. side was +0.43. I didn't even realize that my caster was actually negative on the driver side. For the record, before I put in the engalls kit last week the caster was +0.96 and +1.21. Also for the record, the car always experienced heavy tramlining, the worst on the freeway. And there really was hardly any difference in the amount of tramlining between the two caster settings mentioned above. So basically, the variance in caster was due to the design of the Ingalls camber kit, which allows for some slight adjusting to caster. If you can't picture how this is possible, look at the picture below, think of the left camber adjustment being offset the opposite of the right. As you can see the Ingalls kit can affect caster about a degree if not adjusted while paying attention to caster. (Here's the pic, but you probably know what I am talking about:



Anyways, enough with the BS. After the alignment was done (after sitting and giving directions to the H-tech ) with the UCA's swapped. The front caster went from L: -0.23 to +3.05 and R: +0.43 to +3.45.

First off, I have P/S so this first comment is kind of pointless for anyone without P/S. My initial impression was a slight increase in "effort" required to turn the wheel. (As expected) This was slightly more noticeable at low speeds, compared to higher speeds. (Obviously ) I actually like this feel better then what it was for before, but the difference probably wouldn't even be noticeable to most people.

Secondly, THE TRAMLINING WAS SIGNIFICANTLY REDUCED! (Thank God. ) From 5-40 mph tramlining is reduced, say 50%. (Enough to to easily tell) From 50+ mph tramlining almost doesn't happen. At a nice clip on the freeway, a section where the ruts used to pull mild/medium, I can now let go of the steering wheel and the car stays nice and straight. (Letting go=holding my hands an inch away just in case. So, no flamming.) On portions of the freeway with heavy ruts, like the far right lane or King County (very bad), tramlining is still there a little bit, obviously. But much less then before. Long story short, the faster you go the less the vehicle experiences tramlining. Before with normal caster, the opposite was true. I hated driving on the freeway, even through I drove 500 miles a week. Now it's like I am driving a whole different car.

Also, for those worried about bumpsteer I felt no noticeable increase in this behavior. Granted this was all street driving and I am not going to be an idiot. But where I am from there are alot of country roads where nobody is around. I got a good feel for what the car has/can do and I didn't experince any negative feedback, only positive. Many of these roads aren't the smoothest, so I feel it was a good street test at the least. Anyways, if you have any more questions or comments let me know. I am not the greatest with suspension theory/understanding/lingo, so I am sorry about any bastardization of the field. I hope this was helpful.

-Conlan

 

Awesome write up. This answers some of my questions regarding the "Swapping UCA's" trick and TRAMLINING. Out of curiousity, what are you currently running on your car, as far as suspension, wheel size, and tires?

 

Wow. Thanks for the follow up. This sounds like it could be a very effective mod for street cars. Sounds like a fun project especially if you have a "lifetime warranty" alignment...

Quick Question: Is it noticeable that your front tires are now located a little further back in the wheel well (not centered)? I have a bad caster setting (off 3*) on one corner of my CRX and the wheel is noticeably not centered...

 

I added caster by shimming the two bolts that hold the front lower control arms together. You can barely notice that the wheel is more forward than stock. Not as much as it will be if your suspension is bent. If you add caster using both methods, your wheel will probably be in the top corner on the bumper side.

So people are now in favor of swapping the UCAs? Is it neccessary if you use the camber kit method?

Steering effort without PS isn't too bad just adding a degree or so of caster. In fact, steering effort w/out PS in general doesn't matter above 5mph.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94eg! &raquo;</TD></TR><TR><TD CLASS="quote">Wow. Thanks for the follow up. This sounds like it could be a very effective mod for street cars. Sounds like a fun project especially if you have a "lifetime warranty" alignment...

Quick Question: Is it noticeable that your front tires are now located a little further back in the wheel well (not centered)? I have a bad caster setting (off 3*) on one corner of my CRX and the wheel is noticeably not centered...</TD></TR></TABLE>

I'm running 4.3* caster, and yes, the wheels are visibly pushed back into the wheel wells. Instead of centered, the gap in front is easily 1" larger than the gap behind. If you want caster and are that worried about cosmetics, than the Whiteline caster kit will move the bottom of the upright forward, instead of pulling the top back like the UCA swap does. I've got SPC UCAs, swapped and adjusted for max caster.

Now, I went with a higher caster setting to try to get more rotation from the car, and make turn in better with a daily driver friendly alignment setting. Unfortunately, I changed many things at once, so I can't truely say how much the caster alone added. I will say that turning effort has definately been increased. Turn in is amazing compared to before, but I have more front camber, less rear camber, and less spring front and back at a higher ride height than before, so I can't judge the casters value alone, if any.

In regards to bumpsteer. I haven't driven the car stock in some time, but at 3" lowered and stock caster I had much more bumpsteer than 2" lowered and 4.3* caster. In fact, for a lowered car, I would think more caster could reduce bumpsteer. We get bumpsteer on lowered cars, because the rack is lowered compared to the uprights, and the tie rods are at an angle, higher at the wheel. Since the Civics and Integras (other Hondas too possibly, I just don't know) connect the tie rods behind the upright, adding caster would bring the tie rods closer to horizontal. Doing so will also definately change the ackerman as well though. I have no clue if this change is good or bad though.

 

i did this by accident and notice alot quikcer turn in also. but the steering was really heavy. i dont have power steering.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnjoyTheRideDC2 &raquo;</TD></TR><TR><TD CLASS="quote">Out of curiousity, what are you currently running on your car, as far as suspension, wheel size, and tires?</TD></TR></TABLE>

Koni Yellow's (middle setting)
H&R Sport springs
Heavy *** 17'' MOMO GT2's
205/40/17 Yoko ES100's

I have a one finger gap (1/3'') between every wheel and the fender or quarter panel.

Keep in mind I am running an H22 with most major mods shown in my sig.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94eg! &raquo;</TD></TR><TR><TD CLASS="quote">Wow. Thanks for the follow up. This sounds like it could be a very effective mod for street cars. Sounds like a fun project especially if you have a "lifetime warranty" alignment...

Quick Question: Is it noticeable that your front tires are now located a little further back in the wheel well (not centered)? I have a bad caster setting (off 3*) on one corner of my CRX and the wheel is noticeably not centered...</TD></TR></TABLE>

To bad they will notice that you swapped the LCA's when they see that your toe and caster changed a ton since your last alignment. I tried this, Honda made me pay for half of a new alignment. Which I thought was fair because my caster in the front was within "spec" on the first alignment and didn't need to be fixed, the rear camber on the other hand needed a camber kit to even out camber. So they would have in theory redone my rear alignment for free if they needed to install a part.

The difference in tire position is minimal. I never really looked before, but now my wheel gap looks about 1/2'', maybe an 1'' closer to the rear of the vehicle. I had to look hard to even notice it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slim9300 &raquo;</TD></TR><TR><TD CLASS="quote">I had to look hard to even notice it. </TD></TR></TABLE>

I did too, I was just curious...

About the alignment, that sucks that they won't redo it even if you make changes. I thought thats what it was for. I guess a lot of people (myself included) would abuse it if that was the case...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94eg! &raquo;</TD></TR><TR><TD CLASS="quote">I did too, I was just curious...
I guess a lot of people (myself included) would abuse it if that was the case... </TD></TR></TABLE>

For sure! And I would include myself on that list too.

 

So if my driver side front is catered 1.7+ and the passenger (same front) is .28+ what is my problem. I drive the car and for some reason over rough surfaces the car feels like it going to get thrown to the left. Is this due to the to the caster causing it to tramline? I was told by people befire I could never adjust caster. so this adds new light to my little problem with the car.


Great thread

 

If your caster is uneven from side to side, the car will always want to steer towards the side with less. That's because positive caster wants to steer towards the center of the vehicle. If the other tire does not have that same caster, it does not produce the same force to resist...

Depending on what vehicle you have, you have to figure out which wheel is "out of spec" based on the manufactures tolerances. Since the caster is off, look for one of your front wheels being "off center" in the wheel well. On my CRX, the passengers side is clearly pushed towards the rear of the car about half an inch. Since I have less caster than stock on that corner, I know the LCA has been bent back because that is the only way I could get this result.

Here are some examples:

Wheel pushed rearward + more caster on that side = UCA has been bent back
Wheel pushed rearward + less caster on that side = LCA has been bent back
Wheel pushed forward + more caster on that side = LCA has been bent forward
Wheel pushed forward + less caster on that side = UCA has been bent forward