death wobble

5716 Views 32 Replies 7 Participants Last post by Heartecce, 1 mo ago

maddog3299

Discussion Starter · Jun 10, 2017

Just thought I would post this and hope that it helps someone else that might be experiencing the same thing. After I replaced my front axle setup on the 38 Plymouth last summer, I never really had a chance to drive it due to some other issues. Anyway. I took it out several times this year and noticed if I hit a recessed manhole cover or a good hole in the road at slow speeds, I got the dreaded death wobble. If you have never experienced it, dont. Not worth the wait. I though my lugbolts had come loose or I lost a caliper. My gawd. Scared the peewadding out of me. I took it to a frame shop and they recommended several changes. Get rid of the crap rod ends on the tie rod, reenforce the tie rod with angle iron, take a leaf out of the spring pack, and change the shocks. The old girl has some bounce in her step now and I dont weeble wooble anymore.

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1937Austin

· #21 · Feb 21, 2022

I personally would never use a 1" tube for the tie rod or drag link on a full sized car like your '55. I have a 1" on my Austin, but drag link and tie rod are very short, so they don't flex with the smaller 1" tubing. I used 1.25" on my Falcon, and my 39 Chev because both were around 115" wheelbase, but also had much wider axles that can flex with small diameter tubing.
I have seen too many wider axles with 1" tubing have death wobble caused by the tubing flexing, so I don't use it.

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mmhotrod

· #22 · Feb 21, 2022

1 inch or 1.25 as long as it’s chromoly steel. The bigger the better. What I got with my axle kit was a 5/8 tube so going up to 1 inch and chromoly is a substantial jump to more stability. That 5/8 tie-rod shook my electric fan right off the radiator not to mention I was out of control. Those big heavy tires on Brendon’s front spindles will definitely shock across on uneven pavement or bumps.

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1937Austin

· #23 · Feb 21, 2022

Wonder how your axle had 5/8" tube? If it was 5/8", then what were the heim ends? Or did it not have heim ends? Even my 1.25" OD tube uses weld bungs for 5/8" heim ends.

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mmhotrod

· #24 · Feb 22, 2022 (Edited)

1946Austin said:
Wonder how your axle had 5/8" tube? If it was 5/8", then what were the heim ends? Or did it not have heim ends? Even my 1.25" OD tube uses weld bungs for 5/8" heim ends.

5/8 was the inside diameter. I got my inerds and outereds mixed up. Lol
i bought 3/4 tie rod ends. I think. Ok tomorrow I’m gonna measure the the hole deal. It’s been 12 years and I’m old And confused. 🤣

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Tuske427

· #25 · Feb 22, 2022

mmhotrod said:
Is your tie rod mild steel or chromoly steel? If it’s not chromoly change it. Order a 1” with your exact length and thread you need from Morrison. If it’s mild steel it’s flexing after one side hits a bump or uneven pavement and sending the shock across back and forth causing the shudder vibration. The dampener prevents that from happening. I did that test. Purchased it after I removed the 5/8 mild steel and replaced it with 1” black pipe. Problem went away.
If you do have chromoly then your caster is just not enough like Vall had mentioned. You last mentioned the car was not tracking right so go more Angle. If it was me the steering dampener cure is insurance so I won’t wreck my car. Not a bad thing.

I currently have mild steel, as it's what I can weld with my MIG welder. it's 1.25" OD with a .25" wall thickness. this is what I used: TOYOTA Trail Gear 140266-1-KIT Trail-Gear Rock Assault Drag Links | Summit Racing

My caster is currently 7º

I'll take a look at the chrome moly tubing

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Tuske427

· #26 · Feb 22, 2022

I reinforced my steering arms today, thinking they might be flexing as they're just flat bar stock. Now they are I beams... Also ordered new shocks, thinking that my Competition Engineering drag shocks just aren't cutting it on the street.

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1937Austin

· #27 · Feb 22, 2022

I've used the exact same size and type of tubing you're using on many cars and not had flexing issues. With the larger diameter, and thick wall they just don't flex. I can climb under my car and grab the middle of the tie rod and pull as hard as I can and not get flexing. If I do the same on my smaller 1" tie rod on my Austin I get a tiny bit of flex, but the whole tie rod is only 36" long, so it's not been a problem on that narrow axle.
Hope the reinforced steering arms fix the issue.

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Tuske427

· #28 · Feb 22, 2022

1946Austin said:
I've used the exact same size and type of tubing you're using on many cars and not had flexing issues. With the larger diameter, and thick wall they just don't flex. I can climb under my car and grab the middle of the tie rod and pull as hard as I can and not get flexing. If I do the same on my smaller 1" tie rod on my Austin I get a tiny bit of flex, but the whole tie rod is only 36" long, so it's not been a problem on that narrow axle.
Hope the reinforced steering arms fix the issue.

Thank you, I hope so, too. I took it for a quick drive around the block yesterday and between the reinforced arms and adjusting the steering box it definitely felt better. I think I had the box a tad too tight so I loosened it a little. I also just ordered some smaller tires (60 series) as the car currently has 75's, as I would prefer something a tad smaller up front (more like the 2lbt car had). I photoshopped it and it looks good to me as well, and hopefully this will also reduce some of that gyroscopic force as was brought up elsewhere with my large tires. Another thing I'm doing is changing my shocks. I currently have drag shocks on there and they're probably not suitable for street use (just as the mfg claims, lol) sometimes I have to learn the hard way. Aside from these, my next options are a panhard bar, and that steering stabilizer shock.

What gets me with all this is I didn't have these issues when I first started driving the car. It has only recently occurred, so something (or things) must have loosened up to allow this to happen.

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mmhotrod

· #29 · Feb 22, 2022 (Edited)

mmhotrod said:
5/8 was the inside diameter. I got my inerds and outereds mixed up. Lol

ok I got the sizing I used. The heim end is 3/4” with 5/8 holes and the tube is 1” chromoly.
I don’t even remember what my kit gave me. All I remember is grabbing it in the middle and flexing it. When I got my Morrison piece I couldn’t Flex it.
the tie rod is like 50 inches long.

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1937Austin

· #30 · Feb 23, 2022

What width are your front tires now? A wider tire will have more issue with death wobble.

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Tuske427

· #31 · Feb 23, 2022

1946Austin said:
What width are your front tires now? A wider tire will have more issue with death wobble.

215/75R15. it's a 15x7" rim. The scrub radius shouldn't be too bad (it has some) as the kingpin axis intersects through the tire contact patch. It's not like the wheels sit outside of this..

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1937Austin

· #32 · Feb 24, 2022

Wider tires and wheels can have an effect on the issue, and those are fairly wide. I doubt it would be as pronounced is they were around 4.5"-5.5" front wheels, and a 185 or 195 tire.

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Heartecce

· #33 · 1 mo ago

I guess I will be finding out....I am replacing my tie rod ends with a heim type joints

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