johnc510

Does anyone definitively know what the lug bolt size is for the 991 C2S? I can't seem to find the info and I searched the 991 forums. Saw one posting where 18mm and 19mm was mentioned.

I'm looking to accommodate stock wheel depth + 7mm spacer. I made the mistake of getting silver bolts with my RSS 7mm spacer and am looking to buy black bolts of the same size.

Also, I see a lot of lug bolts on eBay and Amazon but I want to make sure I'm getting quality bolts (not sure if they're all the same or not but I don't want to get inferior bolts). If someone can recommend a brand or actual link to bolts I should buy, that would be very helpful.

Thanks in advance!

johnc510

For example, would these work?

The one and only review of them was from someone who installed them onto a Cayman with spacers (but he doesn't indicate what the size of his spacers are)

FirstF80InSpace

Are you talking about shank length? I believe stock is 30mm. So you would need 37mm if you're going to be adding 7mm spacers.

johnc510

Thanks for your response. The bolt length is just one aspect of it. I also need to know the size of the bolt and thread size. For example, M14 x 1.5. There's also the hex size of the bolt head, which I believe is 19 mm. But again, these numbers are just what I believe/think the numbers are but want to know for sure before I order since there are so many sizes available out there - often off by 1 digit.

FirstF80InSpace

Believe it is M14x1.5. 19mm hex. I would contact Porsche parts just to be extra sure.

991carreradriver

+1

PCNA uses M14x1.5mm for the 5mm spacer. If he is running a 7mm is should be fine. I don't know if he can find a 1.7mm lug.

StormRune

The OEM bolt shank length is 28mm, but it is okay to go a couple of mm past that. The bolts you referenced in your Amazon link would work for 15mm spacers. For 7mm spacers you would want 35 to 37mm. The bottom line is just to add your desired spacer size to 28 to get the shank length, but 1 or 2 mm past that is fine.

Be sure to get ball-seat bolts (R14 if it is even listed), typical for bolts advertised as made for Porsche. M14x1.5 is also correct for the threads. The hex head (wrench) size is typically 19mm, but some including HRE have lugs with a different size head which doesn’t really matter as long as the threads, shank length, and ball seat are correct. If they aren’t 19mm, the in-car tool set won’t fit though... you’d want to carry your own correct socket if that concerns you.

johnc510

Thanks everyone!

Found my stock Porsche bolts and measured it (with a ruler since I don't own a caliper gauge) and I got 29mm for the shank length. As you guys recommended, I'll look for 37mm shank length, M14x1.5.

StormRune, thanks for the additional info on advising me on the ball-seat R14 bolts.