The new Battlax RS10 Racing Street from Bridgestone takes all their MotoGP know how to “offer all we need for trackdays” according to a recent release by Bike Buyers Guide in Ireland.
Better yet, they say that “Bridgestone have created a tyre with new formula compounds and a re-engineered tread pattern that improves acceleration and braking to the point of making them addictive!”
The new Battlax RS10 Racing Street has already been chosen as original equipment on the new Yamaha YZF-R1M and Kawasaki Ninja H2.
The Yamaha was recently launched at the Sydney Motorsport Park in Australia, and amongst the group of journalists was former AMA racer Ed Sorbo, now a serious tuner, writing for the Motorcycle Daily website.
Following his full day of testing, Ed gave his thoughts on the GP Belt technology which Bridgestone has taken directly from MotoGP and placed into the likes of the new Battlax RS10 Racing Street:
“Back when I was racing in the AMA 250 GP class, Bridgestone started building 500 GP tires, and about six months later we got new tires for my AMA class that were clearly better. GP racing really did lead to better tires for regular racers.
So when I pulled into the pits with a big grin on my face after one of my rides at Eastern Creek on the new R1 with Bridgestone Battlax Racing Street RS10 Type-R tires and saw Bridgestone Field Engineer Hisao Suganuma, I asked him if there was any tech brought over from their Moto GP tires to these tires. He said they did and they call it “GP Belt.”
One of the main reasons we use radial tires is that radial tires flex more than bias ply tires, giving a larger contact patch. More rubber doing the work means more grip and longer life (wear is spread over that larger contact patch). Tire companies long ago worked out how to make a radial tire keep a round profile so the bike can lean nicely. But it turns out there is a problem with the big flattened-out oval contact patch, i.e. the center folds away from the ground leaving you with, sort of, an oval shaped donut (see illustration).
Bridgestone’s “GP Belt” pushes back against this center folding giving you the large flat oval you want.”
“I asked how they figured out that the contact patch was folding away, leaving less contact pressure in the middle. It turns out Bridgestone has a machine that can measure the load of the tire contact patch. I think the difference between an oval donut and an oval pancake is clear enough for us to get the idea.
So, how does it work on the track? It’s relatively easy to make tires and suspension that work well when the suspension is loaded. Just think about how loose you feel when you coast around a turn. Stabilizing the tires and the suspension by braking or accelerating is the best way to make any bike work well. But in the real world we often ride on roads and tracks for the first time and we make mistakes, i.e., we get into turns too hot or too slow. Sometimes we even miss a shift.
So there I was riding an open-classer for the first time in many years on a new track after a long flight, a late dinner and less sleep than I wanted. In the first session, lots of coasting, lots of line corrections. These tires don’t care. The standard I want is to know what the surface is doing without being moved off line by any bumps or dips. I want to feel the road without being pounded by the road. This requires just the right amount of flex in the sidewall to take the edge off the bump, letting the suspension deal with the height of the bump but not all of the abruptness. The larger, more uniform contact patch spreads out the work of the tire and makes life better.”
For the launch, Ed also tested the Battlax V02 Racing Slick which had been fitted to the new R1M just for this event. The latest Bridgestone slick also uses GP Belt technology, and Ed reported the same behaviour from the slick, despite going that little bit quicker out on track with the extra grip and increased track knowledge.
Summing up he said “I love the feel I am getting from the tires, I pick my line and the bike goes there. What more could you ask for?”
Check out the new Battlax RS10 Racing Street here.
