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Conversion kits: chassis for Lambretta, Classic and Modern Vespa - at SIP Scootershop

The chassis can and must be modified for a variety of reasons. The more powerful the engine, the better the chassis should be. The older the scooter, the worse it is from the manufacturer. Even with original engine setups, touring is only limited fun. And another reason should not be neglected: the appearance. Many of the conversion options catapult the scooters from the mainstream to the extravagant, and that's not a bad thing.

For which scooter models are there conversion kits for the chassis?

Chassis conversions are very special and not possible on every scooter model. To make this complex topic easier to understand, we recommend limiting the vehicles to your scooter category or scooter type. For example, if you are looking for a conversion kit for a Vespa 180 SS, select "Classic Vespa" in the category and "Vespa 160 GS/180 SS" for the vehicle type. Now you will only see the products that are suitable for this Vespa.

Vespa PX/T5/Cosa/LML Star

The Vespa Cosa 125-200 run on 100 mm wide tyres as standard. On these models the tyres fit with the SIP 2.50 rim:

  • 100`80-10 : front & rear

  • 100`90-10 : front & rear

Ape 50

Modern Vespa

Vespa GTS/GTS Super/GTV/GT 60/GT/GT L 125-300 cc


What chassis conversions are available for scooters?

Conversion to 10'' 110-130 mm rear tyres

The classic wide tyre conversion for large frame Vespas. The rear wheel can be converted to a width of a fat 130 mm or the mighty tyre circumference of a 120`90-10 tyre. Modification of the engine swing arm pivot is required.

Conversion to 10" 100-120 mm front & rear

The rim and tyre of the Lambretta can also be converted.

Conversion to 10" 100 mm front & rear

100 tyres are about 1.2 cm wider than the standard 3.50-10" tyres on most Vespas. If you want to safely use this first stage of wide tyres on a Vespa, you will need slightly wider rims to ensure a secure fit on the rim flange.

Conversion to 10" front & rear

With an original 8" or 9" tyre, potholes become pitfalls, you sit up in curves and the Vespa flutters at high speeds. A conversion to 10" tyres brings a significant improvement here. Conversion forks, conversion rims or brake drum conversion kits are the solution here.

Conversion to 11" front & rear

The rim with the size 2.50-11 and 3.00-11 is the king solution in wide tyre conversion and the youngest child of the SIP wide tyre conversion kits. The 11" conversion is discreet, coherent and only noticeable at second glance.

Conversion to 12" front & rear

Glorious Basterd - Life begins with 12". Weeks of development and many, many prototypes were necessary to develop a conventional solution for the Vespa community. Problems such as toe, steering behaviour and frame spacing were successfully solved. The result is a better chassis quality due to more ground clearance and optimised directional stability. In addition, the 12" wheels are an absolute eye-catcher and extend the gear ratio.

Conversion to 13" front & rear

The GTS rides on 12", which is good and sporty, but also just standard and doesn't knock anyone's socks off. With the conversion to 13", a chassis optimisation is achieved that is not only a visual treat, but also provides driving pleasure. The most stress-free conversion is possible with the SIP rim 13" with ABE even for 140 mm wide tyres.

Conversion to ZIP/ET4 chassis

When using a PIAGGIO ZIP SP steering column, the suspension arm is positioned on the left side. The larger choice of high-end shock absorbers (all from the PIAGGIO ZIP) with a large fluid reservoir external, the shortened wheelbase and the modified geometry are the major advantages of this steering column. Added to this is the strikingly changed appearance.

Conversion from 10" to 8" at the rear

This conversion is especially popular with the old Wideframes.

The top brands of conversion kits for the chassis at SIP Scootershop

Here, the SIP brands are of course at the forefront, because it's not for nothing that Performance & Style is in our logo.


SIP PERFORMANCEtubeless rims, brake drums, wide tyre conversion kits, conversion forks, tyres - everything we could think of over the years to build cool and rideable customs.

SIP SERIES PORDOIthe SIP Custom GTS PORDOI has been specially ennobled. The parts can be found under the logo

SIP LEGAL: In order to highlight the extra homologated articles in the flood of SIP products, we have marked them with the SIP LEGAL logo

PRO SERIES: When smaller tuning companies deliver ideas or implementations, they belong to this label.

Customers ask - SIP answers

"Can I do the conversions myself or do I need a specialist workshop?"

As with most conversions on classic scooters, you can do it yourself. The conversions are not so complicated that you need to be trained as a bike mechanic. Many of the kits are ready to install. However, you should not have two left hands. But the beauty of Vespa and customising is that it's model building in a big way. If you are unsure, lack tools or simply don't have the time, then we recommend going to a tuning workshop. We can also recommend one if you don't know any in the area.