At Josh‘s suggestion, I pulled the foam out of the front tires on my RS10 last night and noticed a big difference in how it takes on obstacles. Hopefully I’ll get it outside this weekend to see how it really handles, but it looks like a good mod to make if you’ve got a stock crawler that could use more grip. I was worried that the crawler would look odd driving around on “flat” tires, but the sidewalls of the stock RS10 tires are rigid enough that you only notice the tire flex when it’s crawling over an object.
A little time-saver tip: You only need to remove one wheel ring to pull the foam out. I learned this after removing both rings and the wheel on the first tire. The second foam removal worked just as well removing one ring and then peeling the tire back to get to the foam. You’ll need to be careful when removing the foam this way as there’s a greater chance the foam will tear, but take your time and you’ll be ok.
Another bit of advice; check out this video (or others like it) on how to mount a tire on a headlock rim. It’s a different (and much easier) animal than mounting tires and foams to standard R/C wheels.