Ball Seat Lug Bolts
Thread Starter
Junior Member
Joined: Dec 2010
Posts: 32
Likes: 4
From: Millstone Township, NJ
2009 SL63, 2009 ML550 4Matic
Ball Seat Lug Bolts
I purchased a set of aftermarket wheels that use ball seat lug bolts which I assume are similar to my stock wheels, but after ordering a new set of lug bolts from EZAccessory.com, I noticed the radius is much different on these compared with the stock lug bolts. Conical lugs are pretty straightforward because there are standard cone angles, but it looks like there are multiple radiuses with ball seat lug bolts.
Is this a big deal? It seems like it would be since they are so drastically different. Looking at the wear on my stock lugs I can see a lot of contact there. With the lugs on the left the contact area would be much less if the ball seat on the new wheels matches the radius on the stock wheels.
Is this a big deal? It seems like it would be since they are so drastically different. Looking at the wear on my stock lugs I can see a lot of contact there. With the lugs on the left the contact area would be much less if the ball seat on the new wheels matches the radius on the stock wheels.
Thread Starter
Junior Member
Joined: Dec 2010
Posts: 32
Likes: 4
From: Millstone Township, NJ
2009 SL63, 2009 ML550 4Matic
I see this question has been raised before with not much input, so hopefully sharing what I discovered tonight will help shed some light on this issue. Almost all conical lugs are pretty much 60 degrees, nice and easy, but I've found there are many different radius options for ball seat lug bolts. The radius is the curvature of the seat. I've seen anything from 12mm to 17mm which is a pretty big difference.
Call this excessive, but I'm glad I did it. The seat on the my new wheels was so deep it was impossible to measure, so I took a clay mold of the wheel seat, measured it with a digital caliper and did an overlay in Photoshop with both the aftermarket and stock lugs.
As you can see from the picture, the aftermarket lugs seem to be a good fit, while the stock E550 ball seat lug bolts (right) would have only made contact with the very outer corner of the wheel seat, and would have almost certainly damaged the wheels over time.
The wheel seat on my new wheels measures 25mm in diameter, and the EZAccessory.com lugs measure 24mm in diameter which should be a perfect fit.
So, as if it wasn't complicated enough to say 14mm x 1.5 pitch x 25mm shank, now you also have to look at seat radius as well.
Call this excessive, but I'm glad I did it. The seat on the my new wheels was so deep it was impossible to measure, so I took a clay mold of the wheel seat, measured it with a digital caliper and did an overlay in Photoshop with both the aftermarket and stock lugs.
As you can see from the picture, the aftermarket lugs seem to be a good fit, while the stock E550 ball seat lug bolts (right) would have only made contact with the very outer corner of the wheel seat, and would have almost certainly damaged the wheels over time.
The wheel seat on my new wheels measures 25mm in diameter, and the EZAccessory.com lugs measure 24mm in diameter which should be a perfect fit.
So, as if it wasn't complicated enough to say 14mm x 1.5 pitch x 25mm shank, now you also have to look at seat radius as well.
MBWorld Fanatic!
Joined: Jan 2004
Posts: 5,939
Likes: 178
From: Seattle WA
99 E320
yes, you do need to pay attention to 1) diameter, 2) length, 3) ball seat even
when entertaining interchange between MB rims. the ball seat on the left
appears to be 12R, versus 14R on the right.
over in the 210 forum, we find that folks are frequently purchasing rims from
later model with 14R and trying to get by with reusing their existing 12R ball
seaters and end up with something more like this....
fortunately we found a source of hybrid lug bolts which feature a 14R ball seat
on a 12mm diameter bolt. pretty neat. unfortunately, there is no cure should
you require a 12R ball seat on a 14mm dia bolt. yes, you should keep the surface
bearing factor as was intended
when entertaining interchange between MB rims. the ball seat on the left
appears to be 12R, versus 14R on the right.
over in the 210 forum, we find that folks are frequently purchasing rims from
later model with 14R and trying to get by with reusing their existing 12R ball
seaters and end up with something more like this....
fortunately we found a source of hybrid lug bolts which feature a 14R ball seat
on a 12mm diameter bolt. pretty neat. unfortunately, there is no cure should
you require a 12R ball seat on a 14mm dia bolt. yes, you should keep the surface
bearing factor as was intended
Last edited by raymond g-; May 22, 2012 at 02:31 AM.
Senior Member
Joined: Sep 2007
Posts: 435
Likes: 6
ml55, Ml63, Porsche, C63S ED1
yes, you do need to pay attention to 1) diameter, 2) length, 3) ball seat even
when entertaining interchange between MB rims. the ball seat on the left
appears to be 12R, versus 14R on the right.
over in the 210 forum, we find that folks are frequently purchasing rims from
later model with 14R and trying to get by with reusing their existing 12R ball
seaters and end up with something more like this....
fortunately we found a source of hybrid lug bolts which feature a 14R ball seat
on a 12mm diameter bolt. pretty neat. unfortunately, there is no cure should
you require a 12R ball seat on a 14mm dia bolt. yes, you should keep the surface
bearing factor as was intended
when entertaining interchange between MB rims. the ball seat on the left
appears to be 12R, versus 14R on the right.
over in the 210 forum, we find that folks are frequently purchasing rims from
later model with 14R and trying to get by with reusing their existing 12R ball
seaters and end up with something more like this....
fortunately we found a source of hybrid lug bolts which feature a 14R ball seat
on a 12mm diameter bolt. pretty neat. unfortunately, there is no cure should
you require a 12R ball seat on a 14mm dia bolt. yes, you should keep the surface
bearing factor as was intended
