Stock lug bolt size vs maximum bolt size

saCusa

Active member
Joined
May 20, 2020
Location
USA
TDI
mk.IV Golf BEW M5
Hi there,

I am aware that the stock lug bolts on these cars is 27mm in length. I'm looking to replace them with conical seat, longer bolts for aftermarket wheels, but I need to know something first before ordering the new lug bolts.

What is the longest length of lug bolt that I can fit on my wheels (with no spacers) before making contact with other objects behind the hub, such as the ABS ring, sensors, etc?

Reason I ask is because I may use 5mm spacers with my new wheels, or I may not. ECS has a wide selection of bolts, but the specific size I need are not in stock at the moment (35mm, playing it safe, but can't wait 10 business days for them to restock) and I need these bolts by next week at the latest! I was going to order 38mm bolts instead. These bolts will definitely work with 5mm spacers in place without issue, but just in case I went to another wheel that didn't require a spacer, I don't want to have to order a whole new set of bolts. Would these 38mm bolts cause any interferences behind the hub, even if I decided to run without a spacer?

Thanks
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Take wheel off. Measure it.
There is not much room back there. I would be surprised if there was 4mm of room before you contact the knuckle with the bolt face past the back of the hub.
Male sure you get the proper shape for your wheels.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
You can use the stock bolts with 5mm spacers. I think the safety standard is 4-6 rotations of the lug bolt before it seats in the wheel. I've used stock length bolts many times with 5mm spacers with no issues.
 

saCusa

Active member
Joined
May 20, 2020
Location
USA
TDI
mk.IV Golf BEW M5
Take wheel off. Measure it.
There is not much room back there. I would be surprised if there was 4mm of room before you contact the knuckle with the bolt face past the back of the hub.
Male sure you get the proper shape for your wheels.
You know, I did measure the rear last night and assumed I would have the same leeway with the fronts, but now I'm reading that the fronts are a bit more spacially challenged than the rear.

For the rear, I measured 35mm from the face of the hub until it made contact with the ABS sensor at the 12 o' clock position. Playing it safe, I can assume 30mm from the face of the hub is OK. Accounting for wheel thickness, perhaps ~10mm, that should allow me to use a 40mm wheel bolt at maximum without any spacers. Unless there's something closer to the hub than the ABS sensor that I didn't see, then that would be unfortunate.

I just looked at an image online of the front hub to kinda.. guess.. that it had clearance. But now I'm reading all over that the fronts have far less space than the rear. Damn.

You can use the stock bolts with 5mm spacers. I think the safety standard is 4-6 rotations of the lug bolt before it seats in the wheel. I've used stock length bolts many times with 5mm spacers with no issues.
Unfortunately I cannot use my nice wheel bolts that I had ordered a year ago for my Ariettas because they're ball seat, and my new wheels are conical seat. They won't fit, or they could cause damage, or perhaps an unsafe condition. I'm interested in none of that!



Edit:
Well I must have got a bunch of tunnel vision, not sure why I limited myself to ECSTuning website. I found the correct length for half the price on Amazon. Booya!
 
Last edited:

PakProtector

Veteran Member
Joined
Jan 5, 2014
Location
AnnArbor, MI
TDI
Mk.4's and the Cummins
It could be that the clearance is not circumferentially the same. Roll the tire around by hand to make sure nothing is going to make hard contact before lowering it for a test drive. I seem to recall running bolts way further in in order to do a better job of securing the rotors to the hubs whilst removing the axles( screw driver between the brake bits thru the vented rotor ). And it rolled over just fine...but do be sure... :)

Douglas
 

saCusa

Active member
Joined
May 20, 2020
Location
USA
TDI
mk.IV Golf BEW M5
It could be that the clearance is not circumferentially the same. Roll the tire around by hand to make sure nothing is going to make hard contact before lowering it for a test drive. I seem to recall running bolts way further in in order to do a better job of securing the rotors to the hubs whilst removing the axles( screw driver between the brake bits thru the vented rotor ). And it rolled over just fine...but do be sure... :)

Douglas
Yea I think I'm going to veer away from using the over-extended bolts, and go with the 33mm from Amazon. They all say powder coated, though, and I don't like that so much. Are the ECS black bolts powder coated as well? They state Zinc, is that some other form of coating that holds up better to tools? I have a feeling the powder coating will crack and break off.
 
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