Thanks for the replies.
From research that I have done it seems that V.W. OE wheels/bolts are indeed R13. Oddly, when I measure the outside diameter of the bolts on the widest part of the curved section it measures 23mm. 23 divided by 2 equals 11.5. 11.5mm is a bit off 13mm and obviously closer to 12mm
I test fitted one Rotiform wheel using my OE bolts. These particular wheels are indeed ball seat but it is unclear as to which type. The ball seat is definitely bigger then that of my OE bolts. When test fitting, the bolts only make contact in a very small area closest to the edge of the bolt hole in the wheel. They do not seat correctly. Please see pictures below. The dark black circle you can see is where the bolt has mated with the wheel and the rest of the seat on the wheel is clean and untouched with no contact made.
I reached out to both Rotiform directly and several Rotiform dealers. Firstly, Rotiform's customer service is extremely poor. I am literally weeks chasing them around with follow up emails to get the information out of them. I originally asked them to confirm what bolts were required. Their answer was "Your stock bolts should be fine but if you are not happy with the fitment you can buy different ones".
They have since told me they are R13 but I am unsure that this is true. I contacted ECS Tuning by email three times over a two week period and never got a reply. (I have also emailed them about other products several times in the past and never once recived a reply). I talked to them via live chat yesterday and the person I was speaking to did not know the OE ball seat radius of V.W. OE wheels or of the Rotiform wheels so could not confirm either, pretty useless... as a nice add on, in order to start the live chat you have to give your email address. Two minutes later I get an email saying "Thanks for signing up for our newsletter" I didn't want to sign up for their newsletter and it didn't mention anything about signing up for their newsletter at the time of supplying my email address to start the live chat. They have sent me four sales related emails now in less then 12 hours. Spam, spam, spam. I unsubscribed this morning
I have also been told by another Rotiform dealer that the stock bolts are correct and a different Rotiform dealer has told me that the stock bolts are not correct and that I need R14 radius bolts. This dealer was very sure that they require R14 and R13 (OE) will not work correctly. I was also told by another Rotiform dealer that they require 60 degree conical bolts which is totally incorrect. It seems that the people who should know the answer to this simple and very important question do not know. I would like to confirm and make sure that I am using the correct bolts to hold the wheels of my car to my car. I find it hard to believe that doing this is so difficult and that there is so much conflicting information between the manufacture and dealers of the brand. Disappointing to say the least.
