So I started last summer with a gallon of Maxima 10w40 synthetic oil from CA cycleworks, and I thought it would be enough for a second change this spring...nope. I can't find it in any of the local stores here, and if possible I would like to avoid having to orde another gallon online for what would be maybe a quart's worth to finish my current oil change.
Is there a risk with mixing in a different brand of 10w40 synthetic oil?
It will be fine as long as you use a same/similar spec oil
I a perfect world it's probably best to stay with the same brand, but due to necessity I've mixed and matched oil many times and never had a known problem with it. That includes various combinations of viscosities and mixing synthetic and dyno oil too.
Bob