Mr Nice wrote:

Neosophist wrote:13mm is the ISO / DIN size head of the M8 bolt.

An M8 bolt will have a 12mm head if your using a JIS bolt to match the rest on the bike... (will stop you having to dig out a 13mm spanner/socket when every other bolt on the bike is 12mm)

So is the difference between the UK spec and the JIS just the different Hex Head size? Are there any grade differences too, as in material used to manufacture the bolt (different steel)? I've no idea what grade the frame is either, so I want to use something that will match and not react.

What length of bolt are we talking, allowing enough to secure the tax disc?

20mm will be long enough,

i dont have any JIS (give or take a few left that i plan to change) all of mine are Stainless Steel A2 allen key bolts.
just waiting on my subframe bolts i order over 6 months ago.

So in short, I'm basically after a M8x20mm stainless steel bolt of my choosing (allen or hex head)?

Shouldn't have much trouble finding something at the motorfactors over the road then if that's the case. I've a spare 13mm spanner in my works tool box which I can just leave with the bike tools under the seat, and I'm pretty sure there's some random allen keys knocking about somewhere too.

It's something I want to get done for the weekend as I'm going for the Wirral Egg Run. Don't want to alert Cheshire's Traffic Plod to the fact I've not bothered to display my disc

and