Conversion to 11 inch front & rear
- at SIP Scootershop
A conversion option for various classic Vespas, both largeframe and smallframe.
The following Vespa models can be converted to 11"
In principle, all those who ride an open 10" rim:
Tyres
110/70-11 front & rear, with SIP 11'' 2.5 rim
For front mounting, a 3mm spacer is required to prevent dragging on the fork. For rear mounting, the rim also fits on the original crankcase. The 3mm offset can, but does not necessarily have to be compensated.
A tuning cylinder with 51-54 mm stroke is recommended. The exhaust has to be partly adapted, racing exhausts and SIP banana exhausts fit without modifications.
Vespa 150 GS VS5T
Tyres
110/70-11: front & rear, with SIP 11'' 2.5 rim (front and rear) or 3.0 rim (rear only)
120/70-11: rear, with SIP 11'' 2.5 or 3.0 rim
130/70-11: rear, with SIP 11'' 3.0 rim
The 11 inch conversion for Vespa in detail
3.00-11
The rim with the size 3.00-11 is the king solution in wide tyre conversion! Our wide tyre rim 3.00-11 comes with two specially developed balancing bushes for the engine swing arm pivot. Further spacing by bushes or with a ring is not necessary! To compensate for the wheel offset, the engine swing arm pivot must be shortened by 10 mm on the right. This moves the engine to the right. Optimal for the use of tyres size 110/70-11, 120/70-11 to 130/70-11.
2.50-11
The ultimate solution for wide tyre conversion! The revised version comes in a harmonised, smoothed design. The rims cause a slight track offset of 4 mm. This means they can be mounted without compensating bushings or similar. At the rear axle these 4 mm can easily be compensated by a small offset of the engine. There, however, they are not noticeable in the driving behaviour even without this offset. With a 110/70-11 tyre, the rims can be mounted on classic Vesps without any problems. The 120/70-11 also fits the rear axle of the Largeframe models.
Which tyre should I choose?
Apart from the width, the height of the tyre is also decisive, as it influences the transmission ratio of the rear tyre. A 110/70-11 tyre has almost the same rolling circumference as an original 3.50-10 tyre, but a 120/70-11 tyre is 4% longer.
Tyre | Width | Circumference | Percent |
|---|---|---|---|
110/70-11 | 110 mm | 1322 mm | 1 % |
120/70-11 | 120 mm | 1365 mm | 4 % |
130/70-11 | 130 mm | 1407 mm | 8 % |
Other decision criteria
Of course, the tyre type must also be considered. Whether classic tyres, all-weather tyres or sports tyres, there is a wide choice here. In addition, the load capacity and speed index play an important role. We recommend our comprehensive Guide to tyres.
How do I mount an 11-inch wide tyre?
Customers ask - SIP answers
"If I want to run a wide tyre on the rear, do I have to saw off my engine swing arm pivot?"
If you shorten your engine by one centimetre on the right side and add the bushes on the left side, your engine moves a bit to the right. This creates air for the wide tyre and allows tracking to the front wheel again. The modification can be reversed by simply putting the bushes on the other side. Both can be done easily with common tools. You don't need to be a locksmith to do this. A hacksaw and mesuring tape are sufficient. If you don't want to touch your original engine, you can also modify a new PX crankcase and put the original engine on the shelf.
