Is your daughter going to jump the bike or ride it like a normal kid ? If the latter, I don't see why a hi ten frame wouldn't last. A bmx frame is short and squatty, definitely sturdy enough for the average 8 year old to ride to school or around the neighborhood. In that case a few pounds makes little difference, bmx's aren't built for speed anyway. And a 50 lb kid isn't going to abuse & destroy a bmx bike anyway. DK has an extensive lineup of products at Wal-Mart that are similarly tiered for pricing.