If you're struggling to get your fly down to the fish in fast-moving water, these rio mow tips are going to make your life a whole lot easier on the water. For anyone who has spent time swinging flies for steelhead or salmon, you know that depth is basically everything. If you're too high, the fish won't move for it in cold water; if you're snagging the bottom every cast, you're just wasting time. That's where these specialized sink tips come into play, filling the gap between a standard piece of sink tubing and a full sinking line.
The beauty of the MOW (Multi-Option Width) system is that it takes the guesswork out of casting heavy junk. Before these were a thing, most of us were just hacking off lengths of T-14 and loop-to-looping them onto our Skagit heads. It worked, but it wasn't always pretty. The transition between the heavy sink tip and the floating head was often clunky, leading to that annoying "hinging" effect where the line just collapses during the cast.
What Exactly Are We Dealing With?
When we talk about these tips, we're really talking about balance. Each tip is designed to match a specific weight class of Skagit line. You've got Light, Medium, and Heavy. The Light ones are built on a T-8 base, Mediums use T-11, and the Heavies use T-14. There's even an Extra Heavy version using T-17 if you're really trying to dredge the bottom of a canyon.
The genius of the design is that regardless of how much of the tip is actually sinking, the total length stays at ten feet. This is huge for your casting rhythm. If you switch from a 10-foot floating tip to a 10-foot sinking tip, your "anchor" stays relatively consistent. You don't have to adjust your stroke nearly as much as you would if you were swapping between a 5-foot and a 15-foot piece of level T-series line.
Decoding the T-Rating System
I remember being totally confused by the "T" numbers when I first started Spey casting. It sounds more complicated than it actually is. The "T" stands for tungsten, and the number following it tells you the grains per foot. So, T-11 means that every foot of that line weighs 11 grains.
If you're using a lighter Skagit head—say something under 450 grains—you probably want to stick with the Light rio mow tips (T-8). If you try to throw T-14 on a light trout Spey rod, it's going to feel like you're trying to cast a wet sock. It just won't have the "oomph" to lift that weight out of the water. On the flip side, if you're rocking a 600-grain head on a big 8-weight rod, T-8 might feel too light, and you'll find yourself "blowing your anchor" because there isn't enough resistance to load the rod.
The Magic of the 5/5 and 2.5/7.5 Splits
One of the most useful rio mow tips I can give you is to stop thinking of these as just "sink tips" and start thinking of them as depth controllers. The MOW series comes in various configurations: * Full Float: Great for skaters or very shallow riffles. * 7.5ft Float / 2.5ft Sink: Just a tiny bit of tip to get the fly under the surface tension. * 5ft Float / 5ft Sink: The "half and half" that works wonders in medium-depth runs. * 2.5ft Float / 7.5ft Sink: When you need to get deep but still want some buoyancy to help with the cast. * Full Sink: The 10-foot heavy hitter.
The floating section on these hybrid tips acts as a bridge. It keeps the back end of the tip from sinking too deep too fast, which helps the line track better during the swing. It also makes it much easier to "peel" the line off the water when you're ready to make your next cast. If you've ever tried to rip 10 feet of T-14 straight out of a deep bucket, you know it's a workout for your shoulders. These tiered tips solve that.
Matching the Tip to the Water
When you arrive at the river, don't just grab the heaviest tip because "the fish are on the bottom." That's a trap. You want to pick a tip that lets your fly swing through the target zone at a natural pace.
If the water is walking-pace fast and four feet deep, a 5/5 Medium tip is usually money. If you're fishing a deep, slow pool where the current isn't doing much to keep your fly up, you might actually need a lighter tip so it doesn't just plummet and snag a rock. It sounds counterintuitive, but slower water often requires a lighter sink rate to keep the fly "swimming" rather than dragging.
Casting Adjustments for Heavy Tips
Let's talk about the actual casting for a second. When you're using rio mow tips, especially the heavier T-11 and T-14 versions, your timing has to change slightly. Because these tips are dense, they dig into the water. If you try to rush your sweep, you're going to get a lot of spray and a weak D-loop.
You need to give the line a second to "set" after your initial move, but don't wait so long that the sink tip gets buried in the substrate. I like to use a slightly wider, more circular sweep when I'm throwing the heavier MOW tips. This keeps the tension consistent. If you feel a "clunk" behind you during the forward stroke, it's usually because your anchor (the tip) was too heavy or you didn't have enough power in your D-loop to lift it.
The Intermediate Option (iMOW)
Standard MOW tips have a floating back section and a sinking front section. But RIO also makes "iMOW" tips, where the back section is intermediate (slow-sinking) rather than floating. These are absolute game-changers for windy days or when you need a perfectly straight line from your rod tip to the fly.
Because the intermediate section sits just under the surface, it isn't affected by wind or surface chop. It provides a much more direct connection. If you're fishing for aggressive fish that might take the fly on the drop, the iMOW tips give you much better "feel" than the standard versions. However, they are a bit harder to cast because you're essentially lifting more "wet" line off the water.
Durability and Maintenance
These things aren't exactly cheap, so you'll want to take care of them. The loop-to-loop connections are the weak point. Over time, the coating can start to crack right where the loops join. I always check my rio mow tips for any signs of the core showing through. If the coating cracks, water gets into the core, and the tip won't behave the way it's supposed to.
A little tip from me: keep them organized. There's nothing worse than standing in the middle of a river with a handful of black sink tips and no idea which one is T-11 and which is T-14. RIO color-codes the loops, but those can fade or get dirty. I like to keep mine in a dedicated wallet with labeled slots. It saves a ton of frustration when the light is fading and the fish are finally starting to move.
Wrapping It Up
At the end of the day, using rio mow tips is all about making your time on the water more efficient. Instead of fighting your gear, these tips let you focus on the fish. You can swap them out in thirty seconds, adjust to a changing run, and keep your fly in the "zone" longer.
Whether you're chasing winter steelhead in the Pacific Northwest or swinging for Atlantic salmon in the Northeast, having a full set of these in your bag is pretty much a requirement. They aren't just accessories; they're the engine that drives your presentation. Just remember to match the weight to your rod, pick the right split for the depth, and keep your casting motions smooth. Once you get the hang of how the different lengths sink, you'll find yourself reaching for them every single time you hit the water.