LS1 front brakes on G body spindle

[Northernregal]

Do you have them yet?

I got my cut down hubs back from the machine shop. They are flat now but not still without problems. I checked the lateral runout on the hubs with a dial indicator. One had 9 thousandths and the other had 3!
Not sure if I should throw in the towel or take them back to the machine shop. This is getting very frustrating.

They shipped today. So probably early next week.

 

[81cutlass]

This is going to be weird to think, but in my experience wheel runout side to side isn't a huge component toward tire shake.

My dad has a set of custom backspace for his 70's pickup and they have visible side to side runout, and the thing has no shakes.

I built my own 15x4.5 steel ralleys and got them sorta OK on side to side runout, even unbalanced they didnt shake.

If you look at many factory steel wheels the runout they have is frightening, and oddly enough they don't shake.

Mentally it's hard to comprehend, but I bet if you bolt them on and test drive it won't shake.

 

[roger1]

This is going to be weird to think, but in my experience wheel runout side to side isn't a huge component toward tire shake.
My dad has a set of custom backspace for his 70's pickup and they have visible side to side runout, and the thing has no shakes.
I built my own 15x4.5 steel ralleys and got them sorta OK on side to side runout, even unbalanced they didnt shake.
If you look at many factory steel wheels the runout they have is frightening, and oddly enough they don't shake.
Mentally it's hard to comprehend, but I bet if you bolt them on and test drive it won't shake.

It's not tire shake I'm thinking about. It's the runout measured at the rotor. I measured the lateral runout at the rotor with the dial indicator base attached to the caliper bracket. I measured 13 thousandths at about 1/2" in from the outside of the rotor surface. This is way more lateral runout than you want to see there. You would expect pedal pulsation and uneven wear to the rotors if run that way.

So that's when I removed the rotor to check and see if it was the hub causing that rotor runout and the answer was yes.

Edit:
I re-measured the amount of lateral runout when I tried trial and error indexed the rotor for the best reading. I torqued all 5 lugs down for this and it changed the measurements a little. Originally I said the number was .011 but turned out to be .013, so I made the edits to correct this reading on this and following posts.
I was able to get a rotor runout of .004 on the better of the two hubs with the indexing of the rotor.

 

[roger1]

They shipped today. So probably early next week.

I'm leaning towards buying these now.
Is it the 270-11043 hubs you have on order?
What lug studs did you order with them? Got a part number you can give me for those?

 

[81cutlass]

Rotors are made a bit wavy (I forget the amount but its in the .005ish range if I remember right) to "force" the pads away from the rotor to reduce friction. If the rotor was 100% parallel and flat the pads would always slightly drag on the rotor, the bit of wave pushes the pad off a few thousands, and you never feel it in the pedal.

It is tough to convince your mind that it is OK, but if you have the parts, it doenst take long to swap the hubs over if they do shake. I would put those on, take it for a drive, and if it pedal pulses you have maybe half an hour per side to remove the wheel, rotor and caliper, swap the hub, and put it back together. I would do that just to confirm that .011" face runout is or isnt OK.

 

[roger1]

Rotors are made a bit wavy (I forget the amount but its in the .005ish range if I remember right) to "force" the pads away from the rotor to reduce friction. If the rotor was 100% parallel and flat the pads would always slightly drag on the rotor, the bit of wave pushes the pad off a few thousands, and you never feel it in the pedal.

It is tough to convince your mind that it is OK, but if you have the parts, it doenst take long to swap the hubs over if they do shake. I would put those on, take it for a drive, and if it pedal pulses you have maybe half an hour per side to remove the wheel, rotor and caliper, swap the hub, and put it back together. I would do that just to confirm that .011" face runout is or isnt OK.

OEM maximum lateral runout specifications generally range anywhere from 0.0012” to 0.0025” measured ¼” in from the outer diameter of the brake rotor with zero being ideal.
I'm not going to run them with .013.

 

[roger1]

Message me, I can try and check tonight.
Or call wilwood.
UMI stocks them too

If you've seen my latest post and new issues I'm heavily leaning towards the Wilwood hubs now.
I may try to call UMI today. I'm just thinking they might be better ones to ask than Wilwood themselves.
Also, Northernregal is going to receive his soon and might be able to help too.

 

[MC96]

If you've seen my latest post and new issues I'm heavily leaning towards the Wilwood hubs now.
I may try to call UMI today. I'm just thinking they might be better ones to ask than Wilwood themselves.
Also, Northernregal is going to receive his soon and might be able to help too.

I can get into mine tonight if you want PM me about 7 to remind me, I just have to pull the caliper off so I can pull the rotor off.

Seems like depending on who you get at wilwood they either read off the website and tell you what you already know or will get your info and give you a call back with an answer.

 

[Northernregal]

The part number in the kit is 270-11043

My kit is 140-12837.

 

[roger1]

The part number in the kit is 270-11043
My kit is 140-12837.

I didn't know that was the kit you had on order. That hub will not work with LS1 brakes. It's designed for their bolt from the back rotor adapter.
The 270-12304 hub is the one UMI supplies in their C5/C6 kit and is the one that has a chance to also work with LS1 brakes.
It all comes down to the outer diameter on whether it will work though. I called UMI and they couldn't check that for me.
I'm presently waiting for a call back from Wilwood to see if they can give the OD or not. They publish all the other dimensions except this one.