New rear tire

[chris900f]

I have 8700km on my bike now and while the front tire shows little sign of wear, the rear was getting pretty thin.

I wanted to try out a 140/70/17, because that is the smallest size you can get in most of the good brands if you want to switch to radials. I thought it best to try on a budget bias, in case I didn't like it (and to match the front bias BT45), before investing in more expensive sport rubber front and rear.

I ordered a Shinko SR016 bias ply, it is a dual compound tire. The price was very good at just $108 CAD. I'm not expecting amazing performance, but I went for an 80km ride today. It was very hot today, so a good time to scrub in a new tire. Did mostly highway and a few things came to mind. These observations are really more about the tire size than the tire's comparative performance to others, but so far it seems like decent rubber at an affordable price.

The 140 changes the rear ride height somewhat--on the centerstand, the tire is only about 1 cm off the ground. This feels a little odd at first, but not too bad--probably something you just get used to over time. I feel more on-top and less in-the-cockpit than with the (worn) 130.

The ride is a bit more cushioned.

I haven't really pushed the corners yet, I'll try more after I take it to a parking lot and scrub in the edges a bit more.

The gear ratio is slightly higher because of the increased diameter. This is actually what I like best about the 140. I generally like the 15t front sprocket better than the 16t stock. I'm not really worried about cruising at 7000 rpm, because the short-stoke twin doesn't really start to breathe until 4000rpm.
The slight increase in gear ratio is about 1/2 a-front-sprocket-tooth worth. So at 100kph indicated the tach shows a hair over 5k and 120kph is a hair over 6k, but standing start take-offs don't "feel" much different.

TLDR: The Shinko SR016 seems like good value, the stock sizes probably handle a touch better, and the small increase in gear ratio knocks a few hundred rpm off your highway speed, without too much of a compromise in low-speed acceleration.