Vespa 8″ Disk Brake

Going faster is nice but I’d argue that being able to stop is even nicer. To have “balanced” performance options in the past typically meant a 10″ wheel conversion or a stronger spring and shock, neither of which are great options. For a Vespa VBB the “Holy Grail” of stopping power is a front disk brake.

I got mine from Saigon Scooter Center, although I’ve seen others that look like it on the internet, offered by other sellers that I’m not familiar with.

THIS IS NOT A PROJECT FOR A NOVICE! It requires welding, metal fab, painting, mechanical and problem solving skills to install. I provided feedback to the seller, he hopes to provide some directions so hopefully future versions of the brake are more user friendly.

The photo above shows the brake. It’s really quite a package; it is a disk brake, stub axle, pivot arms and speedometer pinion all together.

I have a vintage Italian made VBB; I can trace the provenance back to when the scooter was new. This brake kit was made for 8″ Asian-origined Vespas (think VBC Sprints) with a different stub axle design. As a result I had to work through several issues to even do a trial fit. Here’s a list of the problems I encountered and what I did to resolve them:

VBB pivot pin is too shortPurchase pivot pin setup for “1970’s” style axle
Shock bolt does not fit holeReam out the hole with a 10mm oversize reamer
Corrected pivot pin does not fit holeReam out the hole with a 12mm oversize reamer
Pivot pin needs a 6mm bolt and plate to retain pinPurchase pivot pin holder
No instructions on anti-dive arm attached to brakeSolution is to fabricate a lug and weld it to the fork. Purchase pin/ bolt and nut to secure the arm to the fork.
Wheel doesn’t turn freely because brake bleed screw is too tall.Remove brake bleed screw and plug hole. Purchase combination banjo bolt/ bleed screw
Brake pads rub on drum causing metal shavingsGrind down brake pad backing plate
Moving the bleed to the banjo bolt end means you need to remove the caliper to bleed the brake properlyDisconnect, bleed, reconnect
Speedometer pinion hole is too big for original VBB speedo cableSwap out original pinion or replace speedometer with one with larger hole

Let’s look at some of the key installation steps:

Fabricating the anti-dive mounting post:

Handlebar Modifications:

I purchased a combination MMW brake perch. It’s one of the most beautiful scooter parts I’ve ever seen. I used Spiegler modular brake connectors and lines so I could rout the line through the steering fork and minimize the hole I had to drill into my one-piece alloy headset.

Hub Setup:

The key things here were routing the line through the fork (it doesn’t quite fit, I had a lengthy session with my Dremel and a series of grinding stones). The Spiegler system lets you use different connectors to get the hose angle connection dialed in without kinks.

It’s all installed. What’s next? I’d still like to do more testing with it, especially since the centerline of the hub has shifted left 7-9mm from the original. I don’t think it will affect performance (after all the engine isn’t centered in the bike and the difference is within the contact patch of the tires) but I want to be sure. The setup doesn’t allow me to reuse the fork cover from the old bike. I have some ideas on how to fix that, so stay tuned.