Hello, just bought a pair of Grivel G10 crampons and have a question about the fit - My boots are stiff leather / rigid sole Vasque's , size 13. I have the crampons fully extended but when I slide the front of the boot into the crampon, I am having a hard time getting the heel section of the boot to go all the way down. It will go down with some slight force and finnagling but is it supposed to be this difficult? There is a stainless steel metal strap and pin for the length adjustment underneath, I am wondering if there is a hole drilled in the heel end of the crampon right underneath this metal strap { where I can't see underneath it }, that might accomodate a seperate bolt and nut? If so, that would buy me enough length so the boots could be easily placed right into the crampons, but again I am not sure if using some force is normal? The binding is the new classic type. Extender bar is the rigid type, with up to size 14 stamped in the metal. This is what they look like and you can see the silver colored metal strap in the middle.

Sounds like you might need an extended bar.. but I'd say if you can cram the boot in there and it's snug and doesn't put excess pressure on your foot, that's where you want it. To answer the question - yes, you should need to use some force to get the boot seated in the crampon. Not a ton, but some.

This is why I like Petzl's bars... they've got half-measured holes for a more precise fit.

I just discovered { after reading some info on the Grivel website } that those metal strips with the pin can be removed. From there you can go up 2 sizes larger, but the holes need to be secured via a nut and bolt. I just tried it and the boots fit right in now, which still leaves me wondering though, am I better off with buying those flexible bars for my type of boots, or sticking with the rigid bars that came with the grivels? Soles on my boots are pretty rigid but do flex slightly in the front area. They are the Vasque alpine GTX boots.

If you plan on using the crampons with rigid soled boots, stick with the stock bars. If you plan on using them with soft soled shoes (approach shoes, running shoes) then you would want the flexi bars. FWIW, Steve House removes the steel spring/pin assembly and replaces it with a nut and bolt, secured with Loc-Tite, so this seems to be an acceptable practice.

If your crampons are properly adjusted and you put them on the sole of a rigid-soled boot, you should be able to hold the top of the boot and pick up both boot and crampon without the crampon falling off the sole, even without the straps (or lever lock in the case of automatic or hybrid crampons) holding them in place. That generally means that the crampons are quite snug on the sole of the boot, and require a small amount of force to attach to the sole. As Ben Beckerich said, it's some force but not a lot. Of course you will want to attach the straps/leverlock in actual use to keep the crampons securely in place.