After spending quite a bit of time over the last year riding on technical single-track trails like Kennedy Meadows and Frazier Park in Southern California I found myself wishing for a bit lower gearing on the 525. Even though it is the EXC model with the low first-gear the bike does still require quite a bit of clutching through the rock sections. In addition once you clear the technical stuff the bike doesn't seem quite happy to lug along in third, instead it requires a bit of shifting between second and third to keep it effective. On top of this when out in the desert riding in fast areas sixth gear doesn't offer all that much pull, especially if an incline or sand is involved.
To combat these issues I contacted Greg Burns at Ironman Sprockets, also known as Dirt Tricks. These are the same folks that provided our adjustable triple clamps on the bike. Ironman Sprockets has gained a reputation of making some VERY durable sprockets. In fact they give you a one-year wear guarantee that says if you wear your Ironman sprockets out in less than one year you will receive replacements absolutely free! The rear sprockets are laser cut on a CNC machine, then heat-treated and finally nickel-plated. As if this isn't enough of an effective sales pitch the sprockets are also much lighter than a standard steel sprocket and not much heavier than an aftermarket aluminum model.
After talking to Greg about what conditions I mostly ride in he helped me decide on going to 14-50 gearing from the stock 14-48. That combination should lead to less clutching in the technical terrain, close the gaps a bit between the EXC tranny gears and also allow sixth gear to pull a little harder. I agreed on the combo and the sprockets arrived a few days later in the mail. I also picked up a new chain at a local shop to go with the new sprockets and installed everything on the bike.
The first ride out was to the desert. Immediately I noticed more of a snap and the ability to pull the front wheel up easier while running along in 3rd or 4th through desert whoop sections. Out in the open I had a chance to use sixth for a bit and the bike does indeed pull a little harder, not crazy hard but better than stock. Back on the trails the bike required less clutching and I was able to use second and third more effectively with much less shifting. If I were going to be riding all single-track stuff I might even go one or two teeth bigger on the rear. Overall though I felt this was the right combination for the variety of riding conditions this bike sees.
Since installing and
riding with the Ironman Sprockets it has been over six months and they show no
signs of wear. I haven't even had to adjust the chain except for after the
change interval. If you are looking to close the gaps on your 525 EXC tranny, or
just looking for a reliable long-wearing sprocket set give Ironman Sprockets a
call. They sell complete chain and sprocket combos or just individual sprockets.