As we all know, the day of the felt soled boot is numbered, I still keep a pair around for fishing in drift boats, rafts and on ladders, but rubber soled boots will one day be the only thing we can use in rivers and lakes due to AIS (Aquatic Invasive Species). Rubber soles plain and simple suck for traction on rocky river beds like the Truckee River, especially when considering the rocks are wet and covered with algae. Enter the hardened metal boot stud or cleat. These screw inserts can be attached to most rubber (or felt) boot soles and are often infused with carbide for durability and added traction. They work well for the most part, however, like anything else, they wear down over time and need to be replaced. 
Now then, in our local stores, replacement studs go from $30-40 and replacement cleats go up from there; they tend to last me anywhere from 6-12 months and the studs end up costing as much as the boots do in time. 
I found an affective and affordable stud replacement developed by the motorcycle ice racing industry. This product is manufactured by Kold Kutter and because ice racing motorcycles require several hundred studs, they produce these in large quantities at reasonable prices. 
I've tried the 3/8 inch, #8 Pro Series screws and have had good success with them thus far, I'd suspect the 1/2" screw could work as well, but have yet to try it. 
They simply attached via a 1/4" socket or flat head screw driver.
At $20.55 per pack of 250, they cost 12 cent each as opposed to Simms studs which cost $1.50 each or cleats which cost $2.00 each.
Pros:
- Large quantities so you can switch them out regularly and maximize traction
- Very affordable costing less than a 10th of what the Simms product costs
- Great traction (I couldn't tell any difference in traction)
- Rust resistant
Cons:
- Subject to abrasion. Despite having a macro hardness or "Rockwell Hardness" of 52 Vs Simms products which only have 45, the Simms "micro hardness" or abrasion resistance is better due to carbide chips impregnated in the studs.
This one is pretty easy, Kold Kutter all the way. even if they wear down in 4 months Vs. 6 for Simms, they're so cheap, I can swap them out without breaking the bank. Also, Simms only comes with 20 per pack, so you're left trying to figure out how to best place 10 studs per boot, with Kold Kutter, you can grab a cordless drill and go to town, put 20 or more per boot. You'll find a point where you add too many and actually begin to loose traction. Hope you found this useful, and if you end up trying these out, let me know what you think.
