undisputed83

Is that a big deal?

norskagent

Not on dry pavement, probably not on wet also.
Sheldon: "With tires for road use, it really doesn't matter, since tire tread patterns serve no function on hard surfaces.
Tires with "V" patterns are common for motorcycles, and are generally installed so that the point of the "V" hits the road first. This is to help "squirt" the water out ahead of and to the side of the tire contact patch, as a protection against hydroplaning . Since hydroplaning is impossible on a bicycle, there's no need to observe this custom."

BCRider

On bicycles the manner of how the lap of the rubber and belting is done is why some require a directional arrow and others do not. With those types it's best to orient the arrow correctly so that the splice receives the forces in a manner that smooths it down On others it's intended to ensure that the tread is oriented the optimum way. I tend to pay far more attention to this on off road tires with knobbies than I do with road tires. But if there is an arrow I like to follow it unless there's a clear reason not to. For example using a rear specific tread on a front for some reason. In that case I'd reverse it for both the tread AND joint issues.

On the other hand if you did it accidentally and are at all worried about it your time would have been better spent unmounting and remounting it the right way. If you see that as a torturous adventure fraught with danger, daring and risk then you likely need the practice to learn to do it better and quicker and again it would be a good reason to just turn it around.

Retro Grouch 

1. It doesn't matter.

2. But every bike rider who looks at your bike is going to notice and laugh at you.

benda18

fix it the next time you flat

Doohickie

Well... okay. It's not that bad...

CliftonGK1

You can use it as an excuse if you get dropped. "Aw man, this tire's on backwards. That must be what was slowing me down..."