Wheel Bolt Length

I'm just about to fit a set of aftermarket alloys to my MK7 Golf GTD. The wheels are Rotiform IND-T in Silver/Machined and the specs of them are 18x8.5 ET45. Tyres are Michelin Pilot Sport 4 in 225/40-18. These wheels use a radius bolt seat, the same as the OEM wheels.

I'm trying to figure out if I need longer wheel bolts and if so how much longer. The OEM bolts (27mm thread length) when fitted to the OEM Nogaro wheels protrude from the mounting face of the wheel by 19mm.
When these bolts are fitted to the Rotiform wheels they protrude by 16mm so with a 3mm difference one would say I need bolts with a 30mm thread length to match the amount of thread available on the OEM set up but... having done a good bit of research the minimum amount of rotations that is recommended for a 14x1.5 wheel bolt (stock bolt for VW) is a minimum 7.5 turns. So I checked this with my OEM wheels and I only get 6.5 turns from initial thread engagement to fully tightened at 120NM. With the Rotiform wheels I only get 5 turns. So neither are 7.5 or above, not even the OEM setup??

Can anyone advise here?

I did contact Rotiform directly and they gave me an a totally useless answer - they said I should be O.K. using the OEM bolts but if I had any concerns with the amount of thread engagement I could buy longer ones. Great info I'd like to be a bit more solid than "should be O.K." when it comes to attaching wheels to my car to be honest and I can buy longer bolts? Thanks for the the tip... I would have thought that the manufacturer would be able to confirm on what is required.
I also contacted three Rotiform dealers for advice by email and not one replied.

Thanks.

The rule of thumb for me is to have at least 10mm of thread going into the hub. The hub can take a lot of extra length so being too long is usually not an issue, just extra weight.

I run OZ wheels and they tend to have thicker discs than the OEM so I have to use longer stud bolts. I bought several different lengths at ECS Tuning along with various spacers and I just stick the bolt through the wheel while off the car and measure at least 10mm sticking out the other side. This is the same procedure when I check bolt length while using spacers.

Hope this sheds some light.

Thanks for the info.
Only 10mm? Do you know how many rotations that gives by any chance?

Yes, 10mm has always been enough for steel lugs and bolts for me. If you do auto-x maybe you might want to go a tad more. It's hard to tell how many rotations as I use my electric driver and follow up with a torque wrench.

On my Japanese cars, I use 13-15mm for those duralumin lugs which are a lot softer than steel.

Anyone else care to chime in on this?

JHWP said:

Thanks for the info.
Only 10mm? Do you know how many rotations that gives by any chance?

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10mm with a 1.5mm pitch = 6 2/3 turns.


I need conical bolts and Discount tire included Gorilla 17018 (1" shank) with my new wheels and I'm only getting 5 turns as well. I'll be exchanging for 17020 (1.25" shank) which should get me 9 turns. Possibly a little overkill but I'd feel a lot better about it and could possibly run 3mm spacers in the rear if I wanted.

I'm not sure why I am not getting this calculation on my set up
7.5 turns on a 1.5mm pitch thread equates to approximately 11 - 12mm of load bearing thread needed to achieve this. I have 19mm of load bearing thread available with my OEM set up, yet I am only getting 6.5 turns from initial thread engagement to fully torqued at 120NM.

OEM Nogaro wheels on my car
OEM 27mm thread length bolt (19mm protruding on inside of wheel) gives 6.5 turns
Based on this and a 1.5mm thread pitch moving 1.5mm for every revolution -
28.5mm would give 7.5 turns

Aftermarket Rotiform IND-T wheels on my car
OEM 27mm thread length bolt (16mm protruding on inside of wheel) gives 5 turns
Based on this and a 1.5mm thread pitch moving 1.5mm for every revolution -
28.5mm would give 6 turns
30mm would give 7 turns
31.5mm would give 8 turns
32mm would give 8.5 turns

I'm still in the dark with this one. Am i missing something??

did you take into account the fact that the rotor thickness does not have any threads?

i will be following this as i am waiting for snow to melt before i install konigs on the gti. same questions for me, is the aftermarket wheel "thicker" than oem. i know i need to replaced the studs with conical ones but wonder about the lenght...

I’ve been wondering if there is an official VW spec for bolts as well.


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I ran same wheels in 19x8.5 specs with stock lug bolts. Never had an issue.

OP what did you end up doing? Found this discussion as I'm trying to buy the right bolts for my new wheels. Thanks.

morgan said:

OP what did you end up doing? Found this discussion as I'm trying to buy the right bolts for my new wheels. Thanks.

Click to expand...

You might want to try and send him a PM since he hasn't been in the forum for 7 months.

I've never put this much though into my wheel bolts. As long as I got 5+ full turns with my bolts...I'd use them. With my Neuspeed wheels...I just used the stock bolts up front and got bolts that were ~5mm longer for the rear since I used 5mm spacers. I always based my bolt length off the stock 27mm.