280z Steering Wheel Vibration

[chaseincats]

17 minutes ago, Zed Head said:

You could have a bent hub flange or axle.  It happens.  Setting up a crude runout measuring device would tell you.  Jack up a wheel, place a block some kind next to, put a stick on top and place the end close to the tire.  Spin the tire and watch the gap between the stick and the tire.  Do the sides and the tread.

Mine would definitely hit the block of wood as they go around but I think it’s the wheels as some move not than others.  I made my wobble better by finding which ones were more oblong than others and put them on the back.  Maybe try his test and do the same?

[Zed Head]

Actually, it's better to put your pointer next to the rim for side to side wobble.

And, you can also take the wheel off and use a more precise indicator on the flange itself.

Or you can clamp a long lever on to the flange so that the movement is amplified, and use a less precise indicator.

Many possibilities.

 

Edited April 21, 2023 by Zed Head

[Blitzed]

Yeah, the rabbit trial has been long and expensive redoing parts/service twice in two years, new wheel bearings, nope, new tie rods, nope, reset the tension rod preload, nope, rebalanced the wheels and tires (counter), nope. realigned front end, nope. Every suspension bushing was replaced 2020 (rubber). took the car to Mike's Z shop, owner drove the car on the freeway, inspected the front end on a rack for a week, could not find a issue that would cause the shimmy. 

Only part untouched, the rack. 

Will check the hub trueness.

 

[chaseincats]

1 hour ago, Blitzed said:

Yeah, the rabbit trial has been long and expensive redoing parts/service twice in two years, new wheel bearings, nope, new tie rods, nope, reset the tension rod preload, nope, rebalanced the wheels and tires (counter), nope. realigned front end, nope. Every suspension bushing was replaced 2020 (rubber). took the car to Mike's Z shop, owner drove the car on the freeway, inspected the front end on a rack for a week, could not find a issue that would cause the shimmy. 

Only part untouched, the rack. 

Will check the hub trueness.

 

Back when I lived in CA I took my car there too - great guys

[dutchzcarguy]

Another tip would be, take a wheel off and look if the bushing of the lugnut fits perfectly the holes in the rim. I have seen lugnuts with a to small diameter and it gives a lot of (balancing) problems.

[chaseincats]

Building on the above, did you ever try the acorn style lug nuts?

[Blitzed]

Thanks for all the suggestions. The issue is defiantly rotational, as above 70mph it begins to fade, still there but not as strong. Just have to drive 80mph all the time :).

Found the shop to fix the issue. Lucked out and found two guys running a shop who came from the aerospace industry. Designed wheels and tires for NASA vehicle's and speed record cars in Bonneville. Walk into the shop (tiny old building) and they just finished a week at the Long Beach grand prix truing wheels and tires.

https://www.natejonestire.com/

They listen to my story and said you're battling unsprung tension? The service is cheaper than new tires, will report back after. 

[Blitzed]

Hi All,

Trying to correct the vibration feedback in the Z's steering wheel is one of those problems you can chase down a rabbit trail and add additional dollars redoing services, unless you find the correct service / shop. 

Drove the Z to Solvang, CA this past weekend for the Datsun Roadster Classic (they include Z in the show), 340 mile round trip drive and the steering wheel vibration at 60+ drove me crazy the entire 300 + mile drive.  Below 60 MPH puts you in the slow lane/ truck lane on the highway's which is also the roughest lane on the highway which compounded the issue. 

Took the Z to Nate Jones Tire in Signal Hill CA today. Wow, what an eye opener. Nate is an 80 years old, racer, builder and great resource. The service included truing the wheel (rim and tire) on the car. 

Frist tire pressure, Nate knew the Z's stock suspension was designed with a tire pressure rated at 28lbs max. I was running 36lbs on 205. Tires have too pressure for the suppression. He knocked the fronts down to 26 and rears to 28. Suggested with the mass of the tire, could run as low as 24 in the fronts and 26 in the rears for (dry) highway travel, track add 4lbs front and back.  

Next removed and rotated all tires with the valve steam to line up over a stud location. This became the static mounting location for the wheel, on and off, must mount in this location ,no future rotation. until the tire is shot

Jacked the front up and rolled a custom machine (looked like a lawnmower base) and attached to front tire. Hit the inside edge of the rim lip with a small grinding blade, knocked down any shimmy / wobble imperfection in the wheel (rim) during rotation. 

Next trued the tires. We all let our cars sit for extended periods, this can create flat spots that will cure it self over time and miles. The equipment shaved grooves in the tread (top not side wall) and trued or rounded the tire. 

Next rolled another unit to the tire and applied a counter weight ring on the outside of the rim. Than rotated the tire and wheel (on the car) at high rpm. With a several feelers hitting the rim edge inside and outside and a strobe light he picked up the balance position of the wheel and tire at high RPM. Applied weights. 

The end result, vibration in steering wheel gone, vibration in car gone and a quieter cockpit. Great experience with I fear is dying expertise.  

 

 

 

[Patcon]

It's always good to find an expert!

[chaseincats]

On 5/1/2023 at 9:19 PM, Blitzed said:

Hi All,

Trying to correct the vibration feedback in the Z's steering wheel is one of those problems you can chase down a rabbit trail and add additional dollars redoing services, unless you find the correct service / shop. 

Drove the Z to Solvang, CA this past weekend for the Datsun Roadster Classic (they include Z in the show), 340 mile round trip drive and the steering wheel vibration at 60+ drove me crazy the entire 300 + mile drive.  Below 60 MPH puts you in the slow lane/ truck lane on the highway's which is also the roughest lane on the highway which compounded the issue. 

Took the Z to Nate Jones Tire in Signal Hill CA today. Wow, what an eye opener. Nate is an 80 years old, racer, builder and great resource. The service included truing the wheel (rim and tire) on the car. 

Frist tire pressure, Nate knew the Z's stock suspension was designed with a tire pressure rated at 28lbs max. I was running 36lbs on 205. Tires have too pressure for the suppression. He knocked the fronts down to 26 and rears to 28. Suggested with the mass of the tire, could run as low as 24 in the fronts and 26 in the rears for (dry) highway travel, track add 4lbs front and back.  

Next removed and rotated all tires with the valve steam to line up over a stud location. This became the static mounting location for the wheel, on and off, must mount in this location ,no future rotation. until the tire is shot

Jacked the front up and rolled a custom machine (looked like a lawnmower base) and attached to front tire. Hit the inside edge of the rim lip with a small grinding blade, knocked down any shimmy / wobble imperfection in the wheel (rim) during rotation. 

Next trued the tires. We all let our cars sit for extended periods, this can create flat spots that will cure it self over time and miles. The equipment shaved grooves in the tread (top not side wall) and trued or rounded the tire. 

Next rolled another unit to the tire and applied a counter weight ring on the outside of the rim. Than rotated the tire and wheel (on the car) at high rpm. With a several feelers hitting the rim edge inside and outside and a strobe light he picked up the balance position of the wheel and tire at high RPM. Applied weights. 

The end result, vibration in steering wheel gone, vibration in car gone and a quieter cockpit. Great experience with I fear is dying expertise.  

 

 

 

Wish I still lived in CA - I'd be at his door at 8am tomorrow morning haha

UPDATE: I bought some acorn-style lug nuts and noticed the wheel studs centering themselves as I tightened them.  I then spun the wheels on jacks and the tred seemed to not wobble which is a good sign (although I never did this test before).  I will take the car out this week and get a final answer if lugs are the solution.

Edited May 30, 2023 by chaseincats

[chaseincats]

The lugs are the solution, that is all.

[Ownallday]

Thought I would give a continuation and update to what I have found. I may have found the solution to my problem! Years ago my friend gave me his Enkei 92 Wheels from his Datsun 240z and this is what I have been running since then. I have just discovered the 280z hub bore size is 73mm while the Enkei 92 wheel bore size is 72.6mm!!! My wheels are not 100% flush against the hubs is what it looks like I am seeing here! After replacing nearly everything I think this might be it, but what is confusing is other people have used these wheels without problems apparently like my friend. Can someone give any insight? I might buy a hub centric wheel spacer to make sure this is the problem before buying other wheels as I just bought Watanabe wheels but they don't fit currently over my brake calipers and even then it shows Watanabe wheels are 63mm or 70mm so that's saying these wont fit either?