Inside Tech Building a hardtail frame that'll last a lifetime and is still light enough to ride isn't easy, but in the 25-plus years that we've been building mountain bikes, we've learned a thing or two. For the Hardrock we use a 100% proprietary, butted A1 alloy tubeset that is light, but still tough because we put the material only where it needs to be. Optimized Radius Engineering top and down tubes add even more brawn and still manage to shave weight.