Rear tire width

[Guest]

What is the general consensus as far as tire width vs handling here? Specifically in the rear?. I ask because when I got my second 750L it had a 140 or 150 on the back and I was amazed at the difference in handling when I installed the proper 130. The bike was much more nimble and easier to lean into the corners etc. My 850 is due for a new pair of shoes come spring and was wondering if there is any benefit to running a 120/90-17 on the rear or if altering the factory sizes would cause instabilities that I am as yet unaware of. Thanks.

[eil]

General recommendation is this: take the stock tire size from the owner's manual or service manual. Convert to metric. If the stock size is not available, get the next higher size or two. When you increase one tire size, increase the other by the same amount so as to not upset the handling. So if you go up 10mm on the rear, go up about 10mm on the front as well. Doesn't have to be exact, but relatively close.

So in your case on the 850, I would say see how much bigger the front is from stock, and then get a rear which is (approximately) that much larger from the rear stock size.

[ShadowFocus603]

The rear is stock right now at 130/90-17 but if I am interpreting you correctly I am better served by running that size (which is factory) rather than downsizing lest I create handling inconsistencies. The front is stock as well at 90/90-19.

[Grimly]

Mine both came to me with 130/90 on the rear and for years that's all I ran, but I came into the odd tyre bargain of things like 140/80 and 130/80, both of which fitted and handled fine. The 140/80 just fitted, the overall tyre size was still about right and because it was a radial, the improved handling and grip outweighed any downside there might have been from going wider (anyway, wider tyres became more mainstream later on). The 130/80 was turning around 5% faster for a given road speed, but it wasn't noticeable and the handling was fine.
One thing I did, and wouldn't care to repeat, was fit a too-tall front tyre. Caused horrible understeer until I got used to it, but it was always ready to throw me into the weeds and as soon as I could, I got rid of that.

[Big T]

stock is the to go. Some Japanese engineers spent a lot of time figuring that out for you

[Steve]

The tires that will work the best for your bike will be a 130/90-17 on the rear and a 100/90-19 on the front.

Yes, the smaller tires might make it steer a bit quicker, but it might also be a bit TOO quick.

The 100 front tire will slow down steering response just a tad, but it also removes virtually all of the error from the sepeedometer.

.

[ShadowFocus603]

Thanks for the inputs. I'll stick with stock come spring and enjoy the ride.