So far as safety’s concerned, we think that the introduction of tubeless rims for classic scooters was probably the biggest leap forward in safety for decades. However, we know that some riders remain unconvinced so let’s begin by setting out the case for going tubeless.
Feeling deflated
From their inception, scooters have been designed with convenience in mind. Most manufacturers adopted ‘car type’ wheels that could be easily removed and used split rims which meant that a tyre could be replaced at home without the use of special tools. This was incredibly convenient for owners who, bearing in mind road conditions of the time, were travelling at relatively low speeds and constantly at risk of punctures. In those circumstances inner tubes were an ideal solution and that’s why Vespa stayed true to the tubed design for so many years.
However, as road surfaces got better and average speeds increased, tubes started to make less sense. The reason for this is that when a tube is pierced it looses pressure instantly. This effect can be replicated by pricking an inflated balloon with a pin. Tubeless tyres differ because they’re stronger, and can hold a foreign object in place, meaning that deflation is slower. Going back to our balloon experiment, if a piece of sellotape is stuck to the surface of our inflated balloon a pin will pass through it without any rapid loss of pressure.
Not only are tubeless rims able to hold pressure more effectively, if a puncture does occur they’re manufactured with a ‘bead’ that helps to keep the tyre in place on the rim. The end result is a much safer ride and should a puncture occur, there’s a much higher chance of keeping a scooter shiny side up on tubeless rims than on inner tubes.
Finally, manufacturing tolerances are much finer on these rims than on standard pressed metal rims, meaning that a scooter’s handling can feel much tighter and responsive.
If you’re still not convinced consider this, there’s not a single mainstream motorcycle or scooter manufacturer that fits tubed wheels as standard…
Performance and convenience
When tubeless rims first became available they were simply scaled down versions of motorcycle wheels. These ‘solid’ rims are still very popular with our customers and have excellent performance characteristics. Unfortunately, they also have an built level of inconvenience in that fitting (or removing) a tyre is a more complicated process that’s best dealt with by using a professional tyre fitting rig. This is a service we can offer, but many scooterists prefer the convenience of being able to change tyres themselves and that’s where Pinasco’s split rims come into their own.
The problem facing designers who wanted to create a wheel that offered the safety of a tubeless wheel with the convenience of a split rim was how to prevent air from seeping between the two halves. Pinasco’s solution was to ensure that the joining faces were very finely machined and then cut a groove into the joining faces. An ‘O’ ring is inserted into this groove and when the wheel is tightened together this compresses to form an air tight seal. It’s an incredibly simple idea and very effective.
At this point it’s worth mentioning that the first generation of Pinasco rims had five securing bolts and these. together with the wheel mounting nuts meant that the rim was secured at intervals of approximately 63mm. In use, it was quickly discovered that this wasn’t enough to hold air for long periods of time and the number of securing bolts was doubled. The second generation rims are secured at intervals of 46mm and this has proven to be more than adequate .
Tell me about it stud…
One question were often asked is whether longer hub mounting studs are required and the simple answer to this is “No”.
The confusion around stud lengths is probably due to the fact that the first tubeless rims to be introduced for classics were designed for the Lambretta. As standard a Lambretta hub stud has around 11mm of usable thread with pressed rim being around 6mm thick. The most common Lambretta tubeless rim, manufactured by SIP, is approximately 15mm thick and obviously that was never going to work, so longer studs are provided.
In contrast a Vespa stud usually falls between 14-15mm in length with a standard pressed steel rim being 6mm thick. The Pinasco rim is approximately 7mm thick, so there’s no need to use longer studs. The loss of the 1mm is taken up by the use of serrated flange nuts, which are manufactured with ‘teeth’ that bite into the surface of the rim. We’ve customers that have completed testing of thousands of miles using this method of fastening without encountering any problems.
Fitting hints and tips
As the rims are designed with convenience in mind it should come as no surprise that fitting a tyre to them is a straightforward process. Having done this more times than we can remember we’ve come across a couple of tips that make things even easier.
Before describing these, it’s very important to stress that an inert grease such as silicone or PTFE is used during assembly. Other products can damage rubber components and reduce their effective life.
Just as with an inner tube it’s important that everything is lined up correctly. Make sure that the bolt holes are in line, the mating surfaces are free of any dust or grit and the valve stem notch is correctly matched on both faces. Before closing the rims, the O ring can be held in place with some grease, this makes fitting much easier and creates the best seal.
Speaking of the valve stem, this needs to be fitted before the wheel is assembled and can be tricky to pull through.There are specialist tools that make an easy job of this but for the home mechanic it’s possible to make a ‘handle’ using three zip ties. Get this in place and with a little lube the stem can be eased into position.
One thing that many owners don’t realise is that a tubeless rim will not fit on the under panel carrier. This can be solved by using spacer nuts and then bolting through the spare, but this can put strain on the carrier. A cheaper, but less elegant, solution is to carry a standard wheel as a spare together with a few zip ties. If a puncture does occur the tubed rim can be strapped to a carrier until the repair is completed. In a real emergency the tyre valve can be removed and tube inserted.
When fitting, it's vital that the tyre is correctly seated between the rim's edge and bead. When inflating the wheel it may be necessary to temporarily over-inflate the wheel assembly by a couple of degrees until the tyre 'pop's into place. If it doesn't go first time, deflate the assembly, pop a little lubricant down the side of the rim and try again.
Finally, as with tubes, the O ring is a consumable item and should be checked for wear each time a tyre is fitted, fortunately replacements are readily available from our stock.
Maintenance free?
Every week our workshop team is confronted with evidence that some scooterists still haven’t grasped the concept of routine maintenance! One part of an owner’s routine should be periodic checks of tyre pressures and that’s true whether or not they’re tubed or tubeless rims. Care does need to be taken with assembly, but again that’s also true of tubed tyres.
Safety and style
If you’re serious about your riding, we’d recommend an upgrade to tubeless rims and for our money, Pinasco splits are the perfect combination of safety and convenience; not to mention style! Thee are one of our best selling items and our stock levels continually change so whether your preference is for silver, black or shiny aluminium, for more information visit our web-store or give our sales team a call on 01226 203377.
