T/C rods - how do they work?

[cmathews]

I was admiring the wonderfull front suspension of my car yesterday and found this thing I had heard of called the T/C Rod. I have a lot of experience with double A-arm and modified McPherson strut systems (upper control arm - found on Honda's) but have never seen a T/C rod before. What does it do? I tried moving the car up and down to be able to tell, but the suspension is too stiff to move it far enough by myself to tell what it is trying to control. Also, does anyone know what the T/C stands for?


Chuck

[240meowth]

it holds your wheels in place, so when you accelerate the wheels don't fall into the door...  also it's for some kinda suspsion thing for steering.

[cmathews]

I don't know how it would affect steering much. It seems to attach to the subframe and the lower control arm.

Chuck

[240meowth]

trust me, when mine passanger side tension rod broke, i couldn't turn left...  and i need to run on spaire tire 'cause it's smaller, or else the wheel would be rubbing against the inside of the fender

btw. anyone know where to get s13 silvia front end parts?  i need it...

[adey]

T/C stands for (if I remember correctly) Tension Control. I'm not sure exactly what it does, but I believe it does have something to do with steering and alignment.
Bent T/C arms are often the result of some intimate contact with a curb. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> &nbsp;
sorry I can't help out much more w/ what it does!

[mrdirty]

If the lower control arm was completely rigid fore and aft then it wouldn't be necessary; but since it is not, you need an additional member to keep the wheel from rotating (slightly) about the lower control arm toe (I think it's the toe that on the inside?!?). Anywho, it keeps your wheels from moving front and back under braking, cornering and hitting bumps.

[bbp]

the TC rod triangulates the lower control arm. &nbsp;It connects the lower control arm to the body of the car. &nbsp;Many cars have some form of a T/C rod. &nbsp;I remember my CRX had something similar.

It will affect the steering if the bushing inside is worn out. &nbsp;When this bushing wears out, it will allow the lower control arm to move back and forth under braking and acceleration.

bbp

[cmathews]

So, if you changed it out for an adjustable one, would it affect anti-squat as well as caster? (PDM made an adjustable T/C rod on the 240sx listed on their own site)

http://www.pdm-racing.com/features/240sx2.html

They did, however, tell me that it was not avaliable for purchase.

Thanks,
Chuck

[sykikchimp]

I've never heard of anti squat, but with a an adjustable T/C rod you Can adjust caster. &nbsp;The T/C rod is what keeps the Caster aligned correctly by controlling the Tension on the Lower control arm. &nbsp;It basically keeps the Lower control arm from moving back and forth. &nbsp;A lot of postive caster makes it easier for the car to track straight without a lot of adjust ments made to the steering. &nbsp;For eample a Shopping cart has a LOT of caster. &nbsp;the wheels kindof Drag behind the connecting point to the vehicle. &nbsp;now to imagine negative caster, have you ever turned the front wheels of a shopping cart around and tried to keep them that why while pushing it? &nbsp;Not easy. &nbsp;Having some caster is good because it allows for more error while cornering in a drifting type situation. &nbsp;
That's why the 240sx is such a great car to drift. &nbsp;I think from the Factory they have 6-7 degrees of caster. &nbsp;It's what allows you to throw the car sideways, and let go of the wheel, stay on the gas, and the car will straighten itself out. &nbsp;TOO Much caster, and it will reduce turn in speed, and make the car harder to handle.

Understand?

-charles

[sykikchimp]

fyi - there is a thread called "Akerman steering" that talks about slip angles on the rear tires. This technically is what forces the "Trailing" front wheels to straigten out the car in a high speed drift. (why you can let go of the steering wheel and the car tends to go back the other direction)

(I believe SCC calls this "Friction Circles" in the May 2002 edition.. YES, the one with the $3000 Silvia conversion)

[RS13]

if i'm not wrong, t/c stands for 'tension/compression'

[HippoSleek]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (bbp @ May 10 2002,07:15)</td></tr><tr><td id="QUOTE">the TC rod triangulates the lower control arm. It connects the lower control arm to the body of the car. Many cars have some form of a T/C rod. I remember my CRX had something similar.

It will affect the steering if the bushing inside is worn out. When this bushing wears out, it will allow the lower control arm to move back and forth under braking and acceleration.

bbp</td></tr></table><span id='postcolor'>
You rule. &nbsp;period. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/cool.gif" border="0" valign="absmiddle" alt=':cool:'>

I've been trying to explain this to someone (since my bushings are shot) and have been doing a horrible job. &nbsp;This is simple and to the point.

chimpie - it's not just for drifting. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'> &nbsp;In addition to being able to allow caster adjustments, adjustable tension rods also come with a pillow mount instead of a bushing. &nbsp;This is supposed to enhance road feel through the wheel b/c you have metal-on-metal contact in place of a bushing. &nbsp;Also, the characteristics that make them functional for drifting apply to every other type of driving. &nbsp;(OT: saw Planet of the Apes last night and really thought about you... no sh!t. &nbsp;Weird)

I'll let you all know what I think in a couple weeks, after I get my East Bear units on (they should be on their way now! <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'> )

[240racer]

any anti-squat that would be in a suspension is done to the rear suspension. &nbsp;If you did something to change the pitch of the car on the front suspension it is usually called anti-dive. &nbsp;

tension compression is correct. &nbsp;The rod is under tension when you are braking. &nbsp;It is under compression at other times, mostly when bumps are involved, if it were a front drive, then it would be when you were accelerating.

think of a regular a-arm lower link suspension, the T/C rod is just the forward link and the lower link is the rearward link. &nbsp;Both are need to hold the hub fore/back.