I think this really depends upon the type of tire you have as well as the riders ability. Take Moto GP for instance, they lean a lot more (by training, lack of

I think this really depends upon the type of tire you have as well as the riders ability. Take Moto GP for instance, they lean a lot more (by training, lack of fear and other factors) than a street rider would. Part of this is tires. They use tires that are more rounded and don't really have a noticeable sidewall. I have Michelin Pilot 3's on my bike and I feel safer leaning more with then the stock tires that were on the bike. As a side note, my bike is more upright than most, so this has a lot to do with my ability to lean. I feel very comfortable leaning farther on a bike where I am not already leaning really far forward to begin with. Note: I have a 2012 Triumph Street Triple. My wife has a 2012 Triumph Daytona Ultra sport. Mine is more upright, hers is a significant forward lean.