280z Steering Wheel Vibration

[Patcon]

What centers the wheel on a Datsun? The hub bore or the lug nuts? I had always thought the lug nuts centered the wheel. If thats the case the hub or wheel could be relieved so it sits flush. If thats not the case then it gets tougher and the machining needs to be more precise

[Ownallday]

5 minutes ago, Patcon said:

What centers the wheel on a Datsun? The hub bore or the lug nuts? I had always thought the lug nuts centered the wheel. If thats the case the hub or wheel could be relieved so it sits flush. If thats not the case then it gets tougher and the machining needs to be more precise

I know Z cars are lug centric and not hub centric. If the wheel is less than 73mm then in that case means the wheels wont sit completely flush against the hub? Or am I missing something.

[Zed Head]

Seems unlikely that 0.4 mm would be a factor but it should be easy to find out.  There should be damage on the inside edge of the wheel where it was crushed against the hub weld.  If you see damage, you should be able to file away 0.2 mm around the inner edge of the wheel hole to create a clearance chamfer easily.  A few swipes with a round file.

The pattern on the back of the wheel is also a good indicator of seating.  The spot behind the lug nuts is where the force is.

https://www.ebay.com/itm/186288432645?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=fN_3lKgHSjG&sssrc=2047675&ssuid=bBzFtXzvTQO&widget_ver=artemis&media=COPY

[Ownallday]

7 hours ago, Zed Head said:

Seems unlikely that 0.4 mm would be a factor but it should be easy to find out.  There should be damage on the inside edge of the wheel where it was crushed against the hub weld.  If you see damage, you should be able to file away 0.2 mm around the inner edge of the wheel hole to create a clearance chamfer easily.  A few swipes with a round file.

The pattern on the back of the wheel is also a good indicator of seating.  The spot behind the lug nuts is where the force is.

https://www.ebay.com/itm/186288432645?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=fN_3lKgHSjG&sssrc=2047675&ssuid=bBzFtXzvTQO&widget_ver=artemis&media=COPY

Noted, going to be removing the wheels and looking into everything sometime next week. My wheels look like the lug holes have been repair sometime in the past I'll have to post some pictures of that. The only thing I have yet to replace in the front at this point is the wheels and tires (going to swap wheels and tires with a friend in two weeks if it's still isn't resolved), the steering rack, and the wheel hubs. Still haven't got rid of the vibration to this day.

Also even though I replaced my struts and have lowering springs, not sure if it can still be that because if the road is perfectly smooth the wheel doesn't vibrate at all, but if there is any very minor road imperfections is when it vibrates at nearly any speed so it varies with road surface.

[Blitzed]

Read my post from 5/1/2023. Tried everything vibration would not go away. The stock (I said stock) Z suspension control arms with rubber bushing were designed for max 28lbs -30lbs tire air pressure on narrow tires. You're probably running a wider tire with a manufacturer suggested air pressure of 32lbs or 36lbs.

I don't race but have been told most car drivers will reduce air pressure on the track. So just reduce your air pressure to 24lbs in the fronts and 24lbs in the rear and see if the vibration goes away. If so, begin to add pressure 2lbs at a time to find the tipping point with the tire pressure / suspension and the vibration. 

I'm running 25lbs fronts and 26lbs in rears on the street (15 60 205), no vibration. Is the car harder to steer at low speeds, yes but the steering wheel is much more enjoyable at driving speeds.

Took it a step further and had the wheels (rim), tire, hub and rotor dynamically balanced (single wheel dyno) on the car. Downside, wheel must remain in the same position on the car, mark on the hub and no rotation. 

Good luck. 

[Ownallday]

3 minutes ago, Blitzed said:

Read my post from 5/1/2023. Tried everything vibration would not go away. The stock (I said stock) Z suspension control arms with rubber bushing were designed for max 28lbs -30lbs tire air pressure on narrow tires. You're probably running a wider tire with a manufacturer suggested air pressure of 32lbs or 36lbs.

I don't race but have been told most car drivers will reduce air pressure on the track. So just reduce your air pressure to 24lbs in the fronts and 24lbs in the rear and see if the vibration goes away. If so, begin to add pressure 2lbs at a time to find the tipping point with the tire pressure / suspension and the vibration. 

I'm running 25lbs fronts and 26lbs in rears on the street (15 60 205), no vibration. Is the car harder to steer at low speeds, yes but the steering wheel is much more enjoyable at driving speeds.

Took it a step further and had the wheels (rim), tire, hub and rotor dynamically balanced (single wheel dyno) on the car. Downside, wheel must remain in the same position on the car, mark on the hub and no rotation. 

Good luck. 

Thank you, yes I have psi right around 32 psi. I'll try an reduce tire pressure and see what results I get with that. I run a 225/45r15 and I have the technotoytuning control arms and tension rods. Maybe the combination with higher tire pressure and my hankook Rs4 the tire tread catches into the road surface aggressively? Anyways I'll reduce it to 25psi and see what the results are next week. Thanks for the tip.

[chaseincats]

23 hours ago, Ownallday said:

Thank you, yes I have psi right around 32 psi. I'll try an reduce tire pressure and see what results I get with that. I run a 225/45r15 and I have the technotoytuning control arms and tension rods. Maybe the combination with higher tire pressure and my hankook Rs4 the tire tread catches into the road surface aggressively? Anyways I'll reduce it to 25psi and see what the results are next week. Thanks for the tip.

I don't think PSI especially that minor change would affect much outside of making flat spots on your tires more noticeable (do you have any?).  The FSM I believe says your car should be sitting at 28 psi.

[Ownallday]

9 minutes ago, chaseincats said:

I don't think PSI especially that minor change would affect much outside of making flat spots on your tires more noticeable (do you have any?).  The FSM I believe says your car should be sitting at 28 psi.

I've tried anywhere between 30psi to 35psi and no difference. To the eye and feeling with my hand there are no noticeable flat spots. And I've already tried balancing the tires at work at least 10 times.

One thing I will say is on the driver side I can here a slight click or tap noise when moving the tire in the same manner if you were to check for wheel bearings. However I cannot get that noise with the wheel off the car. This might be leading me to believe that the wheel studs might be ever so slightly too long and the lug nuts aren't 100% pressed against the wheel to the hub. The car has extended studs and were cut slightly but maybe they weren't cut enough for the wheels I have. I have a 5mm spacer coming so I can check when that gets here.

[Ownallday]

Quick update. Adjusting the tire pressure had no change or effect any where between 25 psi and 35psi with the steering shake. I finally got my wheel spacers that are also hub centric and no change to the vibration either. I went to double check for play and noise when moving the hub and even with the tire off I get a small clunk/thump sound when moving up and down. My wheel bearings and ball joints (Part of the TTT control arm) are maybe only two years old at best with less than 15k miles on both. You guys think the hubs could be bad? I am almost at the point now where I am just going to order TTT hubs with new bearings. Two videos of the noise below.

Yes I know the surface rust on the rotor looks bad btw. Going to fix that soon.

 

 

 

[chaseincats]

Have you tried the tapered lugs like I tried?  They fixed my shake.

[Ownallday]

33 minutes ago, chaseincats said:

Have you tried the tapered lugs like I tried?  They fixed my shake.

My lug nuts are tapered. I'm using the same lug nuts my friend used when he was running these wheels and he had no shake.

[Zed Head]

Your wheel bearngs are loose.  Even though there is a somewhat complex process for setting tapered wheel bearing preload, you can get really close just by tightening them by hand.  Pop that cap off and turn the nut until it's hand tight. 

Your aftermarket lugs are so long it wouldn't be a surprise if they were bottoming out in the nut. That rust and corrosion on the hub should not be there, where the nut is supposed to be clamping the wheel down.  That's a sign that the wheel is not seating on the hub.