Trinity765 wrote: ↑Fri Mar 11, 2022 2:31 pm
To Spin or anyone........
I once followed two riders, both of them were on the same bikes with the same tyres. They both went into each corner the same distance apart and remained the same distance apart throughout. One rider however was leaning a lot more than the other. What were they doing differently and who had the greatest advantage?
Most likely body position - lean body in, bike sits more upright.
If you do the maths (and I don't have the book which gives you the formula to hand at the moment) you'll find that there's a tiny advantage to be gained by leaning in (and thus lowering the combined Centre of Mass of bike and rider) but it's really only of any interest at the fine edge of race pace if you hang off like a gibbon. On the road it's not worth worrying about, and that means lean in or sit up only changes the part of the tyre on the deck. The forces involved are almost the same.
Ironically, the road rider sitting upright and leaning the bike over more might have more grip since most rear tyres are dual compound!
But the thing you always have to remember on the road is that what you do on the bike doesn't ultimately control grip. The road surface does. It doesn't matter what you are doing with your body or the bike mid-corner if the surface isn't generating any grip for the tyre to stick to. That's why track sessions are all very well for getting a feel for what the bike is doing under you but it doesn't mean you should translate that new lean angle confidence to the road.
FWIW I'm generally slower in corners than some riders, but quicker either side - I had a very frustrated RoSPA instructor behind me on a trip to the Pyrenees some years back on a bike with about double the HP. He commented that every hairpin I was holding him up but he couldn't seem to get past me either.
It was easy enough to explain. He was trying to hold max speed and lean round the hairpins which meant pinpoint accuracy. I was using Point and Squirt.
Where he was rolling off the throttle and beginning to lean in, I was still upright and going deeper in by using the brakes to get the bike slowed. The lower mid-turn speed meant I could use a positive steering input to get the bike turned more rapidly, which meant I had the bike pointed where I wanted to go next earlier in the corner. With the bike upright again sooner, I was on the gas earlier whilst RoSPA bloke behind was still trying to get out of the corner because he was on that wide, max lean line. It took him ages to get the bike stood up again and to be able to use his extra 75 hp, by which time I was long gone.
