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Grinding and Punching Limits

post #1 of 8
Thread Starter 
I'm downsizing from 27.5 Krypton Pro's to 26.5 Il Moro's and need more toe room. After reading the recent threads "Best approach to making room for big toe" and 'Grinding vs. Punching". I'm wondering what is the maximum space that an experienced bootfitter can create? You hear these stories of racers downsizing two or three shell sizes... How much wall thickness can be removed? How deep a depression can be punched? Does thinning the wall by grinding make it easier to punch a deeper bulge, or just increase the risk of a split? The Dalbello site lists the shell material as D-62 polyethylene. Does anyone have experience punching this material?

I made some rough wall thickness measurements in my old Krypton shells by drilling 1/16" holes at the big toe contact point and the center of the heel and used a bent paper clip as a crude depth gage by feeling with my finger when the tip of the wire was flush with the inner wall. The toe thickness was 1/4" and the heel was 5/16". I'm guessing it would be OK to remove half of the wall thickness near the big toe and hoping it could also be punched out an additional 1/4". Perhaps more than half of the wall thickness behind the heel could be removed (without additional punching) to shift the foot back a little.
post #2 of 8
With punching you are just streching the plastic that is around that point, I've had some spot punchs hold that are 15mm. If you are stretching a general area (width, not a bump) then maybe up to 20+.

grinding: you can remove about 50% of the thickness of the shell in that place, but punching after that you have to be slow and careful. as the area is thinner and will heat up fast, and you have less plastic to pull from.

follow all the other advice to more toe room too (socks, foot beds, heel back) etc first,
post #3 of 8
Thread Starter 
Thanks for the info. It sounds to me that a good strategy to gain room in front of my big and second (Morton's) toes would be to skip the grinding and go for a maximum local punch. The toebox width is fine and the other toes have plenty of space up front. If this material has a memory and won't hold a deep punch, then maybe try grinding 50% of the wall thickness.
post #4 of 8
Well, mcleanro, I would be cautious doing any stretching at the toe of the boots because this radius is a DIN standard and changing that external radius shape of the boot may affect binding release in some models. I personally prefer grinding at the toe and hold my finger on the outside while grinding on the inside to feel when and where the grind is thinning out the material thickness. I will grind until I can flex the plastic with my finger or thumb if needed.

As Mosh pointed out in another thread, if you are desperate for more toe room you can actually thin out the heel pocket to allow the foot to move back more.

You should be able to get into a 26.5 Krypton if your feet are up to a size 10.5 without too much work. My foot is 11.5 on a brannick and I can comfortably ski a 27.5 Krypton without any toe grinding.

good luck!
post #5 of 8
also don't forget that many of the liners are actually quite a bit shorter than the shell in recreational boots. (I'll leave that determination up to you and the shop guys that have the experience). You can gain quite a bit just by stretching and removing the padding on the liner. and you really should do this before trying to expand the toe area.
post #6 of 8
good point Dchan!
post #7 of 8
Agree with everyone. You can get extremely large punches reliably in the medial and lateral forefoot area and elsewhere. But be careful about considering those numbers realistic in the toe area itself.

As for stories about racers. I've heard them myself. But I work with some Canadian National Team members and what I've heard and what I've seen are two different things. I've yet to see someone that measures a 27 for instance skiing in a 25.
post #8 of 8
Thread Starter 
Thanks guys for the excellent info and advice. I forgot about the binding interface when considering toe punching. I do have some Look and Salomon bindings that contact the toe box in addition to the sole lug.

I had the bootfitting done this weekend and ended up only needing some grinding in the outside corner of each toe box to fit my size 10.5 feet in the 26.5 shells. The translucent material made it easy to mark the contact points for grinding. With the liners removed and my bare feet and footbeds in the shells, the fitter marked the contact points with chalk on the outside of the shells.

The stock Intuition foam liners that came with the Il Moro's are short lasted and jammed my toes when I first tried them on. They can be lengthed by heating in a convection oven (rather than in-the-boot heaters) although maybe not as readily as other models that don't have heavy fabric reinforcing the sole. I haven't tried molding the stock liners yet, since for now I've fitted the Il Moro's with my old size 27.5 Zipfit Plug liners.
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