Jump to content

Runout of wheels


wvumtnbkr
 Share

Recommended Posts

Good Day!

 

I am adapting some new brake hardware to the front of the car as well as running new wheels.

 

When I get everything bolted together, I can see about 1/8" of runout on the tire.  I am about to go to harbor freight to get a dial indicator to check the actual wheel.

 

Is this alot?  it seems to be there on my new brake setup and old brake setup.  New wheels, old wheels, etc....

 

Im a little worried this is kind of a lot of runout (Out of round).

Link to comment
Share on other sites

Hmmm...  like when I spin it, the tire moves up and down.

 

Not hub centric.  None of my wheels are actually.

 

Several different pair of aluminum wheels.

 

I never noticed it before, but I'm not sure if it was there before.

Link to comment
Share on other sites

Suspect you've answered your own question, try again with some kind of hubcentric ring in there.

 

OTOH, everything has a tolerance. I know that some of the colored dots that you see marked on the side of tires indicate runout, so maybe some research into that would give insight into what's typical/acceptable.

Link to comment
Share on other sites

20 minutes ago, ABR-Glen said:

Suspect you've answered your own question, try again with some kind of hubcentric ring in there.

 

OTOH, everything has a tolerance. I know that some of the colored dots that you see marked on the side of tires indicate runout, so maybe some research into that would give insight into what's typical/acceptable.

Not sure I answered anything.  I'm still trying to figure out if it matters.

 

This car has been racing for about 10 years without hub centric rings.  

 

Never had a vibration or anything.

 

Can somebody check their car and see how much movement they get?

8 minutes ago, tommytipover said:

I'm sure you've loosened the lugs, wiggled everything and re-torqued?

 

Yep.  Even tried et style lug nuts.

Link to comment
Share on other sites

I have more info...

 

When bolted on, the rotor has .002" of side to side run out.  Pretty good, I would think.

 

The wheel has .125" and it visibly wobbles.  I have tried 2 oem wheels and 1 aftermarket wheel.  All about the same.

 

I'm wondering if the hub is somehow bent.  However, I would think the rotor would wobble too if that was the case.

 

I have another 2nd gen front end here (on a first gen car).  I'm gonna check the wheels on it.  If they are nice and true, I'm gonna swap hubs and see what happens.

Link to comment
Share on other sites

yessir!

 

I got out the actual, real dial indicator.

 

I measured stuff on the first gen and the second gen (same wheel, same wheel spacer, etc...)

 

The runout I measure side to side is about .005" on the 1st gen.  it is about .010" on my car.

 

The "vertical runout" is about .025 to .035" on my car.  I still need to mount the wheel on the 1st gen and measure it.

 

I am absoultely shocked that I can see that much runout and think it is WAY more.  I even took the dial indicator and put grease on it and measured teh smear mark with a set of calipers.  Sure enough, it is only .025 to .035" (the reason I am giving a range is because it matters where the indicator is on the wheel).

Link to comment
Share on other sites

I wouldn't worry about it.  As someone who has watched 1,000s of tires spin up on a wheel balancer, I'll can you they're very rarely smooth.  All tires have some level of "hop" when free spinning.  Untill it gets really out of control from a bent wheel or failing tire, it's rarely anything to make a stink about.  Thats why they make road force tire balancers, to try and account for radial runout.

 

If you're worried it's the hub, mark the low or high spot on the tire, then rotate it one set of lug holes and retest.  If the hub is bent the low/high spot will move in relation to your mark.

 

Ive run into quite a few bent hubs before, and usually they'll cause odd brake noises and feelings before tire vibrations.  Like worn out pad ears, or a "clacking" or rythimic "wering" sound when the pedal is lightly applied.

Edited by SonsOfIrony
I can has proofread
  • Like 2
Link to comment
Share on other sites

If the wheel balances and you can't feel anything when driving the car, it is fine.  I mount and balance my own tires and have multiple wheels like that.  I just put them on the rear to make sure.  Never feel a thing.  Kind of surprising, but.....

  • Like 1
Link to comment
Share on other sites

2 hours ago, DaveH said:

It could be that the rotor face isn't square.  The rotor mounts to the hub face, the wheel mounts to the rotor face.

True.  However I tried about 4 different rotors as well.

 

I'm satisfied where I'm at now.  I put my wheels on the other car and they were the same.  That car never had vibrations.

 

I guess I just never noticed it before.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...