Cannondale Slate/650b
 

I'm really into the idea of a 650b gravel bike, particularly for better toe clearance. Does anyone have good recommendations or experiences with a 650b gravel bike? I also really like the looks of the Cannondale Slate, but for $3000, I'm a bit reluctant. I'm also not sure how well the lefty fork (with only 30 mm of travel) would really work.

I have a slate 105 which I paid $1500 for and I really really love it. I mainly ride it on the road (probably 80%) with slicks on and it's much quicker than I was expecting, I think I was only down about 1mph average on my regular routes. Roads are so smooth with it, I have so back and shoulder issues and with this bike I was comfortably able to ride twice the distance that I could on my old fancy kevlar 17lbs road bike. I'm thinking of getting a second site of wheels for it with some grippier tires, the tires are very difficult to mount, easier to just swap wheels. The slicks are great on crushed gravel type paths and hard dirt paths, but you get into loose stuff, larger gravel, or heaven forbid mud and they are pretty useless. I really like the lefty, plenty of travel for me especially with the big fat 650b tires
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I love my Slate. My only gripe was limited stem availability because of the 1.5inch steerer but I have remedied that with the Project321 1-1/8 steerer conversion. I have Byways and they are plush on the road and offer somewhat decent grip offroad. I am getting a second set of wheels made though for some Donnelly X'Plor MSOs for when I will be riding mostly dirt.

Haven't had any trouble with the Oliver so far. You don't have to ride on dirt or gravel to notice it working either. Riding a crappy paved road you feel it doing it's job.