by Adam_Winstone » Mon Dec 08, 2014 7:40 pm
Please note: This is not just an issue of angle, it is also an issue of where the valve stem is located on the tube. Lambrettas rims meet in the middle with both halves being an equal depth, meaning that the standard Vespa type, which have an offset design, are not really suitable for Lambretta use. The correct tubes for Lambrettas have the valve stem off centre so that the stem can come up through the hole in the rim, without being pulled off-line by the inflation of the tube. Many/most of you will have noted how right angle valves often bend over badly so that they end up with the cap sitting at nothing like 90 degrees to the wheel alignment, which indicates that the valve is in the wrong place.
The correct off-set valve stem tubes are available from various places, including Just Lambretta, Scootopia (noted on Sunday at Peanut Duck), others (?).
A number of people have put tube blowouts down to the stress placed on the valve stem, when using the common (wrong!) tubes in Lambretta wheels.
Adam