Part 2: One-Armed Bandit (single fork) Lambretta | TECH
In part one we looked at why a single-sided Lambretta fork conversion could be a better option, in this part, we ride the scooter to find out if it is.
Is a mono-fork any better?
In trying to find the answer to this question for you I had to pilot Casa Performance’s race-winning SST265 endurance racer around a freshly-built Italian racetrack under the November sun. Not a hardship at first glance…
The flipside was that I’d be learning both a new track and a new 40hp scooter with sequential gearshift in the company of a load of really fast kids on tiny motorbikes. Let’s put it this way, Donald Trump’s ego wouldn’t be able to handle a loss of face this big. Certainly, there would be litigation claiming unfair practices from the tiny teens who barged up the inside at the hairpins.
If it wasn’t for those pesky kids
In my first session I really couldn’t comment on the forks because I was all at sea; trying to find my way around a new circuit while being dive-bombed by whippersnappers. I alternated between using too much back brake for the corners to putting my foot over the carb and making the engine splutter.
By far the worst problem (from what seems like a compendium of excuses) was the feeling from the fully slick PMT rear tyre. It felt for all the world like it only had 10psi in when I knew it was closer to 30psi. A 40hp Lambretta is a handful at the best of times, but the soft sidewalls of the PMTs deliver the same feeling as a puncture. On full gas the walls of the tyre distort, the back end feels like its sliding and your natural reaction is to shut the throttle. When you do that the tyre springs back to its normal shape and it causes the handlebars to flap. I’m sure from the grandstand it looked like I was trying to tame a bucking bronco. Or inept. Or both.
If you watch the last few seconds of the previous episode’s accompanying video in slo-mo you can see how a smooth rider like Luca Fuschini can adapt to these tyres. At the apex of the corner he lays down so much power that the tyre distorts and spins, laying big black lines before gripping and sending the front wheel into the air. The PMT slicks are worth one second a lap, if you can get used to them.
I couldn’t. Nor could I make any assessment of the fork while the scooter was trying to fling me off.
Thankfully Lorenzo had another rear wheel for me to try, fitted with a Mitas race tyre, as I’ve run before on my SS90. It made all the difference. Suddenly I could feed the power on through the long opening corner that leads onto the straight.
Weren’t you going to tell us about the forks?
OK, I’m coming to that. They make a massive difference to the handling. The advantage stems not only from having more suspension travel to use, but also from the fact that this travel is properly damped. Also, unlike the standard Lambretta set-up which is pro-dive (braking hard uses up all suspension travel), the Vespa fork design is dive-neutral (it only dives due to weight transfer, not the action of the brake). In this way you can brake hard and there’s still some suspension travel to deal with ripples in the tarmac. Personally, for the road I like the anti-dive Lambretta brakes which also behave in this way. Standard Lambretta forks with a good brake tend to go solid and pogo from one pothole to the next under braking.
As for cornering, the SST felt much more planted than I’m used to from a Lambretta. Unsurprisingly, the front end felt a lot more like my racing Vespa. As with all things to do with suspension and handling, the difference is one of ‘improved feel’ that is quite difficult to convey in words. On the track the big advantage was how much trail-braking you can use as you start to tip into a corner, allowing for later braking.
VIDEO | Sticky testing the single-legged fork
To be honest Pomposa’s pristine surface was perhaps not the best place to test these forks but I did manage to get a quick spin around the block on a much more typical Italian road surface (like the Luftwaffe had visited) and the difference was even more candid.
Essentially this fork does exactly what suspension should do. It keeps the tyre in contact with the road and the rider insulated from the bumps better than I’m used to on any Lambretta.
Road or race?
If you are thinking of using this fork for racing, then you first need to check if it will be allowed in your series (currently it isn’t in the UK for BSSO or BSEC). You could argue that through the modifications made by Casa Performance that these are intended specifically for Lambretta scooters. Good luck with that.
For the road, it’s a different matter. Anyone with a really quick engine will appreciate the difference in handling. If you are in a country – like the UK – where you could fit these to a road scooter without legislative problems, then you’ll love the way they handle.
I suspect two factors will limit the success of these forks
Firstly, there’s the cost: which will be 550 Euros for the Polini fork adapted with your choice of Lambretta stem. On top of that, you have a massive choice of fork links, hubs, wheels shocks and brakes covering the range from breakers-yard low-cost to break-the-bank high-end.
The second factor is the styling. There are plenty of people who would accept the price and the ride improvement if not for the fact that a single-sided Lambretta fork is the Devil’s work.
Even Mickey from Casa Performance admits that the look of the fork was initially a problem for him, now having ridden it and seen how it handles he’s slowly warming to it.
I’m sure that many successful arranged marriages work in the same way…
Additional photos: Mihaela
For more on the CP Polini fork conversion for Lambretta keep an eye on Rimini Lambretta Centre
or the Casa Performance section of the SLUK Shop.