Originally Posted by JohnJ80

^this



Because of this.

I have a background is fitting ski boots for alpine racers where a lot of similar problems occur but the fit is even more precise.

What happens when you put pressure on your foot is that the arch natural changes shape to act a little like a suspension system. That's great for walking but if you have high arches and they are subjected to the pressures found in cycling (and alpine skiing) they will compress downwards and cause fit issues in the shoe. Your shoe lacing is fairly static and is generally tightened when you're not pressuring the foot so when you do pressure it, the arch starts to compress and the shoe is then loose. That can lead to all sorts of mischief in fit and foot position. Obviously, if you tighten your shoe to the point where that won't happen, you're going to be in a lot of pain over the long haul if you can even stand it in the short haul.

Frequent problems with this "loose in the shoe under power" phenomena is that your foot will slide to the inside or outside often causing pain that is hard to make go away by fooling with other things. If you properly support the foot, the sliding stops. In ski boots, this is critical for good edge control. Often times when someone with a high arch but no insoles but the crappy stock ones in their ski boots goes to a custom insole, they start catching and edge everywhere because they now have edge control that they didn't have before. For beginning racers, this is a very big deal and a major speed trick.

The solution is to fill in under the arch - hence the need for insoles. The insoles need to match your arch closely. If, for example, you have a high arch and you put in a low arch support insole, you'll have problems to the degree that there is space between your arch and the insole. So getting this fit right is important. To a lesser degree, you can have the same problem with the metatarsal arch (google it and look at the foot anatomy). Often that needs support as well and is frequently the source of the hot pain in the front of the shoe/ski boot. There are insoles out there with a metatarsal arch "bump" that can be huge in helping problems in the front of the foot.

What I do is by SOLE insoles. They are heat moldable but I think their method of heating up the insole and standing on it is silly because you compress the arch when you really want the arch supported. What I do is get out a heat gun and spot heat the areas that I want to form and then manipulate the insole with my fingers and the handle end of a screwdriver. That permits me to get a metatarsal arch that I want and I generally have a pretty good fit to their high arch version. You can get them in thin version for close fitting shoes like those for cycling.

The other arch that has worked really well for me is one from Sweden called ICEBUG. They have a very thin version with a prominent but soft metatarsal bump. Use these in my Sidi carbon soled shoes that are a very close fit and they work great.

J.