Wheel bolt length

O.K. stupid question time. cf_emoticons__BangHead: I'm trying to fit a set of ats classics to my mk1 instead of the wellers that are on there.

The problem is that the wheel bolts are too short  as the classics are thicker metal.

How do I know which length of wheel bolt to order without ordering one of each?

Cheers for the help. 

The bolts you have that are too short, do they just grab a thread if so just measure the length of that bolt and add on the extra length you want. If the are too short to even do that. Pop the bolt in the wheel and measure the distance from the end of the bolt to the face of the wheel that sits against the hub, add that length to the existing bolt length and then add on the extra needed to go into the hub, they are m12 x 1.5 I think so 5 threads would go 7.5mm into the hub.

Cool,

 I didn't want to get bolts that were too long as it'd be a waste of 30 quid.

Cheers.

My bolts were too long so I just ground them down to the required length, its an easy fix if you do happen to buy bolts which are too long.

  Just logged in to ask the very same question!
So if I needed an extra 5 treads on top of the existing original lenght, how long would the new bolts have to be?  
     I don't mind doing my own homework but if it's been done already it saves me the bother and much appreciated,   cheers

Original bolt length plus 7.5mm would get the length you want if you are after another 5 threads. But as fathammer has said go long and cut/grind down, better that way than too short

35mm it is then,

Cheers again people.

they may be tapered thread rather than ball seating as per VW wheels, to check squish a blob of blutak or similar into hole and note shape

if tapered then try BMW wheel bolts, perfect size for most VW with aftermarket wheels and have 17mm hex head as per OE

Excellent. Thanks all.