Modern Vespa

Hello!

We were just replacing the front brakes on my husband's GTS 300, and one of the bolts for the brake caliper decided to be unhappy. (Stripped the head when putting it on.) Bolt is on, and probably going to be uncooporative about coming back out for the next break change. We'd like to have spare bolts around, in case of a repeat, but paying $15-20 for a pair of bolts seems... excessive. I know the bolt is a M2 x 18, but I'm curious about the thread pitch. Does anyone happen to know the correct pitch, so we can just pick up a box of the right size from Ace?

Thanks!

I don't think M2 is right.

Looks like M8x18, and only a couple bucks each?
https://scooterpartsco.com/gts-300-brakes-c-3637_3643_3801/bolt-for-brake-caliper-m8-x-18-tcei-p-36454.html

The bolts that hold the caliper to the bracket are M8x40

Part 13

Take the bolt to Ace Hardware, they have nuts and bolts of many sizes and thread pitch mounted on a board. You will be able to find a match!

Sorry, typo'd. Yes, it is a m8, not m2.

My concern is the thread-pitch (distance between the ridges). Last time I took a screw from the Vespa to ace, we found the right size/length, but the thread pitch was wrong. Couldn't find one with the right pitch.

I can't take the current screw in, b/c it's actually on the brake.

I'd rather buy a box of the screws for less than 2 screws + shipping from scooterwest, if I can!

M8 1.25 is what you're looking for

wheel bolts are the same pitch if you need to take one in with you.

but rest assured that it's 1.25

If you're going to do this, I'd suggest you also make sure they are of the same grade. Brake mounting bolts will almost certainly be high tensile steel, not standard carbon steel.

https://boltdepot.com/Fastener-Information/Materials-and-Grades/Bolt-Grade-Chart

The problem with buying the correct parts (which usually are excessive in price), is you will never know if it really did prevent a crash and a catastrophic hospital and/or repair bill.

It looks like this is the right answer, and Scooter Partsco is a reputable supplier that many of us use.

Wrong length as i showed above

Depends on the GTS. The M6x16 bolts are the ones that screw the caliper into the steering stem. The ones you found attach it to a bracket, which then attaches to the steering stem. The simple way to figure out if these are the correct ones or not is to measure the one that did actually come out, because the OP has at least one that came out. If it's the stubby, short ones, everyone who pointed out the part on our site is correct. If it's the 40mm ones, you are correct. Problem solved.