Modern Vespa

Putting Bitubo rear shocks on my 2007 GTS 250.

When I watch the Scootwest video I see the right side spacer being installed on the outside between the shock and the retaining washer/nut. This doesn't make sense on my 2007 250.

On my 2007 250, with the shock on the mounting shaft, there's nothing but threads left sticking out and the spacer is too large for the threads, it's more like a loose washer. If I put the spacer on first it fits perfect on the shaft coming out of the swing arm plate, but will push the shock out a little further, unlike the original stock shock. The original stock shock has the offset on the right, no spacer. The offset seems to be there to cover the shaft up to the threads. The bitubo mounted next to plate without a spacer seems to cover the shaft right up to the heads. I'm thinking I should I just leave the spacer off.

The bike in video is a newer 300 GTS. I'm assuming Bitubo makes these shocks and spacers so to conform to different models and configurations and there a few variations in installation of the spacers.

Does this make sense? Any help would be welcome.

Another look at the stock vs Bitubo

Another look at the shaft/threads without the spacer.

spacer is needed. from your last pic you can see the threads stop just short of the shock. try the spacer on the inside,

the pic of the stock and bit next to each other you can clearly see the thickness difference in them, spacer is needed to make them the same thickness

can you accurately measure the length of the smooth and the threaded parts of the shaft. I've got a 300 one sitting on the shelf and I'd be interested to compare.

definitely don't stick the spacer on the inside as that would make the centre line of the force incorrect. you want to match the centre line of the original.

are they the WMB model or the less common WMI?

the manual for the WMB and the WMI both show the spacer on the outside

your photo shows a tiny bit of the smooth part of the shaft visible so wiothout the spacer there would be horizontal movement -> bad. use the spacer

manual for the wmb:
https://www.sip-scootershop.com/download/article/1/pdf/3e10b214-2a22-4994-8915-3f8e9f4f909a/Montageanleitung_Mounting_Instruction_SC180WMB01-02_IEF+-+REV02.pdf?contentType=application-pdf

manual for the wmi:
https://www.easyparts.fr/documentation/12841/SC180WMI01V1_IEF_-_REV01.pdf

Ol as Dirt, you are correct, there is a very slight bit of smooth shaft showing.

SteelBytes, thanks for the links.

It's the WMB version. The manual you sent has a picture showing the spacer on the outside. The paperwork that came with the shock does not include that. It would have been helpful. The manual that came in the box does have a QR scan that takes you to another link but that doesn't show that picture either.

The picture in the link you provided clearly shows the spacer on the outside. When I tightened the nut the bushing compressed a bit and with the help of a screw driver I was able to center the spacer on the end of the shaft. It looks good now that it's torqued.

Big thanks!!