techno toy tunning tc rods

[kully 560]

has anybody used these tension rods ? and if so can you give a report as to pros and cons. looking to be able to adjust my caster .I only found these so far .there rods bolt up metal to metal on frame support , no bushings used .

I do not know if this is bad as far as feed back in steering wheel or does it not make any difference between using a urthane bushings ,or the metal on metal the way these bolt on to frame thanks kully

[Mike W]

I just completed a total refresh of my front end, including brakes, master cylinder and booster, as well as an upgrade to the Techno Toy Tuning t/c rods.

They are an extremely well built upgrade to the stock t/c rods and also do give adjustability to caster. I did get a little concerned about using them after I read a number of nightmare stories where t/c rods were breaking due to the use of poly bushings on the rods. You are correct that the TTT rods bolt up to the frame member with no bushings at all, and that caused greater concern given the lack of any flexibility at the mounting point. Based on my concerns I did talk to Gabe at TTT about this. I believe that he is the owner as well as the designer of many of their products, and he assured me that I did not need to worry about this under any normal driving situation. He told me that the hime joint will absorb the energy from normal impacts and these would not be transmitted to the frame in any great amount.

So I installed them and set them at the closest setting that matched the OEM length. I had the car aligned right after this installation as I had also changed my rack and tie rod ends, but it turned out that the caster was pretty much where it was supposed to be so I really didn't get the benfit of having this adjustable.

I have only driven the car for less than 100 miles sinced I completed all of this work, but I can say for certain that responsiveness, tightness, etc are much better than before. I am not able to tell you the contribution of the new t/c rods to this improvement as there were so many other things that I changed / upgraded at the same time.

Finally, I can tell you they look great as well.

I've attached a few pictures so you can see them being installed on my car.

Mike.

[kully 560]

thanks for your reply mike. when I purchase the 260z in 1979 I did not notice it was in a small accident and my caster is off about 1-2 degrees on the drivers side. so I purchased a caster adjusting kit from msa auto about 15 years ago and now the rubber bushings are starting to crack and split apart . now these bushings are no longer made so I can not replace them,so I am looking at these tc rods with deep interest. do you or can you tell me is there any feed back in the steering wheel ? I understand you only drove it for about 100 miles thanks kully

[donplau]

I installed these in my 75 280. I also went with their lower control arm set. After I got the car aligned the tech stated the the rack was in good shape. I was wondering what he was saying as I always thought I needed a new steering rack. I was amazed of the responsiveness and tightness of the steering. Road feel through the steering wheel is noticeable, not obtrusive. Driving over bumps (city/highway) the steering wheel does not jerk though. With these two items I do not need a new rack. Before there was too much play n the steering wheel.

Btw, I had previously installed the aluminum/delrin camber adjusters in the control arms. I would not recommend these. I had a knock in the rear that I could not figure out for years. I took the metal camber adjusters out and installed poly bushings. Result , no more knocks.

[gogriz91]

Thanks for asking this question, I just picked a set of these myself and am ordering the AZC steering knuckle/bump steer spacer combo. I couldn't help but think that a stouter piece than stock without a bushing would beat the daylights out of the frame but Gabe says no and there's someone else on here or Hybridz has said he's had a set for a couple of years and they work great.

[John Coffey]

He told me that the hime joint will absorb the energy from normal impacts and these would not be transmitted to the frame in any great amount.

Not true. Rod ends, spherical bearings, and/or heim joints are designed to directly pass through all loads. Except for the thin Teflon or Kevlar liner, they are an all metal connection.

[John Coffey]

You guys do not understand the loads that go in through the TC rod. The rod does not take 100% of the loads from the suspension hitting a bump. That is taken by the spring. The TC rod just locates the LCA and handles part of braking loads.

[Jeff G 78]

No John, but the TC does take the longitudinal loads when a front tire encounters an impact event like a frost heave or the vertical face of a pothole. On a track where there aren't many impact events, the TC loads aren't terribly high, but on the street, I'd guess they could get very high. Here in SE Michigan with countless frost heaves and potholes, I would think that the loads into the body could get rather high with the TTT TC rods.

[John Coffey]

No John, but the TC does take the longitudinal loads when a front tire encounters an impact event like a frost heave or the vertical face of a pothole. On a track where there aren't many impact events, the TC loads aren't terribly high, but on the street, I'd guess they could get very high. Here in SE Michigan with countless frost heaves and potholes, I would think that the loads into the body could get rather high with the TTT TC rods.

Remember, the tire is rolling and will roll over the bump (unless its a curb) and that act of rolling moves the tire up and compresses the spring. That's where the majority of the load goes. What other force is causing the spring to compress?

BTW... Rubber TC rod bushings are better for a street car. By letting the tire move backwards just a bit, the tire can more easily move up and transfer the impact load to the spring.

[John Coffey]

On a track where there aren't many impact events, the TC loads aren't terribly high

FIA curbs are pretty big bumps and I used to run over four or five every lap at Buttonwillow - more at Streets and Sears Point. Even had special valving in the Penskes to allow the suspension to compress quickly at high shaft speeds. Ran stock TC rods with the Aluminum/Delrin bushings. Never broke one.

[Jeff G 78]

Remember, the tire is rolling and will roll over the bump (unless its a curb) ...

Have you been to Michigan?

Our frost heaves can be brutal and act almost like curbs. The potholes are exactly like curbs. Most around here are 3-4" deep with vertical walls. I agree with you otherwise, but I still think MI roads would tear my body apart if I had TTT TC rods. Right now I have poly TC bushings and the impact harshness is ridiculous. On roads without abrupt vertical features, the ride is completely acceptable.

[Jeff G 78]

FIA curbs are pretty big bumps and I used to run over four or five every lap at Buttonwillow - more at Streets and Sears Point. Even had special valving in the Penskes to allow the suspension to compress quickly at high shaft speeds. Ran stock TC rods with the Aluminum/Delrin bushings. Never broke one.

Again though, FIA curbs are not sharp edged, so the loads will be almost entirely vertical.

I'll ask my coworkers that design suspension for a living and ask them what kind of longitudinal loads we see on potholes. As an aside, I had to run a test once where we disabled the ABS and hit a pothole at 45 mph with the brakes locked. After three passes, the front wheel centerline was noticeably pushed back and the front subframe was bent. This was on a production car. Needless to say, we saved that test for the end of the vehicle's useful life.