Don't do it. The Sigma stem is a poor idea, and since it allows for no steerer projection through the stem and has a low stack, if you use less than about 10mm of spacing under it there's no turning back short of buying a new fork. That's why they're basically giving one away free with every Alpha purchase.
Don't do it. The Sigma stem is a poor idea, and since it allows for no steerer projection through the stem and has a low stack, if you use less than about 10mm of spacing under it there's no turning back short of buying a new fork. That's why they're basically giving one away free with every Alpha purchase.