Big tires are only part of the Plus size story. Without the solid base of a wider rim, big rubber will never live up to its potential. That meant the creation of a new category of wheels. Yes, Plus bikes have been around for years (mostly 29+), but the availability of components has been fairly limited.
Fortunately for brands like Sun Ringle, it seems to be pretty easy to miniaturize a fat bike rim to create the perfect platform for mid size tires. So it should come as no surprise that the Mulefüt 50 SL shares all of the features of the Mulefüt 80. Maybe the only surprising aspect (or not) is how little there is to complain about…
Like all things Plus, rims are all about that width. Specifically the 44.4mm internal width on the 50mm wide rim. That seems to be the sweet spot for getting the most out of Plus size tires and they performed well with the WTB Trailblazer 2.8s. The 50 SL wheelset is available in both 27.5 and 29″ versions, but was tested here in 27.5″.
Sort of a single wall/double wall hybrid, the single wall rim has two channels just under the bead seat that form dual wall tunnels to give the rim additional strength.
In spite of the cut outs, the Mulefüt 50 SL is a perfect tubeless ready rim. The aggressive bead seats for the Sun Ringle Tubeless Ready System make the tire really snap into place. This can make the tire difficult to remove, but it’s a necessary feature when you plan to run tubeless at low pressures. Regardless of the pressure I could not get the tires on the Mulefüts to burp or slip. The tires also seat very easily for an effortless set up. In order to make the tubeless seal there is a nylon rim strip that covers the rim cutouts, then a single layer of tubeless tape similar to others on the market. That is all that’s needed and it has provided a solid seal since day one.
Everything needed to go tubeless is included with the wheels, even sealant.
The Mulefüt 50 SL certainly isn’t the lightest wheelset, but you cannot fault them for durability. Low tire pressures mean the occasional touching of the rim on rocks and roots, and in spite of many twangs that would make any rider cringe, the rims are still without flat spots or dents. More impressive though, was the time a giant stick flipped up into the front wheel and caught on the fork sending me straight over the bars (while climbing). The force was great enough to break the stick in half and flip the bike almost instantly, yet the only damage to the wheel was a bent spoke. Considering the rim is single wall where the brass nipples seat, I was amazed it didn’t pull through the rim. The wheel didn’t go out of true either.
If you read my SRAM GX 1 review, there seems to be a bit of a pattern with plus tires flicking large sticks directly into the spokes. I’m not sure if this is a Plus-specific thing or something due to the tread pattern of the WTB Trailblazers, but I have never had an issue with so many sticks getting caught in the wheels.
At the center of each wheel is a fairly basic yet quality 32h Boost hub* with sealed bearings and 6 bolt disc mounting. The free hub is available with either Shimano/SRAM 9/10/11 or SRAM XD standards each with 3 pawls for 10 degree engagement. The hubs sound louder than the average 3 pawl free hub, but no where near as loud as a King or I9. The wheels are built with Wheelsmith Double butted j-bend spokes and brass nipples.
*Wheels are available with 100×15 or 110×15 front and 142×12 or 148×12 rear hubs. They are sold individually in case you have a bike with mixed standards.
Personally, I have zero complaints with the Mulefüt 50 SLs. None. As shown above, they are on the heavy side, but those weights do include the full tubeless set up. This method of weighing fat bike wheels (and rims) has popped up a few times recently – to fairly compare rims with cut outs to those without, they should really be weighed with the necessary elements to run tubeless.
As noted in the Hayduke review, the wheels and tires hide their weight quite well. Whether that’s due to the added momentum, grip, or ride quality is hard to quantify, but you would probably never know you’re riding a pair of wheels that weigh in at more than 2300g. Would I appreciate a lighter wheelset? Sure, but not at the expense of durability and ease of setting up tubeless. The biggest weight savings would probably come from the hubs which wouldn’t have much effect on performance.
If this is the starting point for Plus wheels there is probably more that can be done in terms of weight, but the Mulefüt 50 SLs deliver all the Plus size durability and performance you need for $564 for the set (wheels sold individually).
