Specialized FATBike Wheelset – Start into a new series

Specialized FATBike Wheelset – our start into a new series

DT Nabe, Guide RS Bremse, XX1 Kassette, H.E.D. Felge. Herrliche Aussichten!

FATBike wheels – we're gonna give you some insights!

Hier geht's zur Deutschen Version!

Well… After wrote so much about FATBike tires we thought it's time to have a look at a tire's best friend: the wheel. Most FATBike riders stick with the OEM wheels that the manufacturer has installed. How sad is this! There are a couple of very interesting alternatives in the market today which make your FATBike lighter, smarter, faster or simply much more expensive. A good example for all three is shown above.

We will feature a whole series of articles on this topic whereas we will dedicate one article to each wheelset. But don't worry, there are not too many around…
Our intention is to give you all information you need about weight, sizes, conversion kits / fit and price. And we will take a look at potential tubeless capabilities. For the latter we will give you a rating which is strictly subjective, highly unprofessional and looks as follows:

  • 100%: Perfect! It's all nicely prepared to throw that nasty old rubber hose over board. The rim seals tightly and tire is strongly fixed. Everthing is in place out of the box. Nothing to buy, nothing add. Just go!
  • 75%: Good to go! The rim might not be perfectly sealed or needs some rework. Technically its all there but you may have to buy some additional stuff to get it going.
  • 50%: Worth a try! Tire is well fixed in its position but might need some more pressure to stay in place. You have to buy plenty of tubeless ingredients to make it happen.
  • 25%: Hmmmm… The wheels are not indicated for tubeless use and lack some important features. However with some workaround it could work. We don't recommend to go for it as it may not be reliable under all everyday circumstance.
  • 0%: Get out and buy yourself a tube! You will be wasting your time.

The fact that we start with Specialized is fairly simple: there's not much to say about the FatBoy SL wheels so there was space for this introduction. And we chose to move from low to high price. That doesn't mean we go from cheap to high-class. Value for money will be a separate topic.

The Specialized FatBoy SL FATBike wheelset

Specialized FatBoy SL Vorderrad

Specialized FatBoy SL front wheel

Okay, enough of introduction. Let's get down to business. Specialized now offers their race proven FATBike wheelset in the aftermarket. And as indicated above they do this for a fairly reasonable price. Unfortunately they currently limit the offer to one application. This directly leads us to the first chapter.


Passt, aber leider nicht überall. Die Stout Nabe

It fits. Sadly not in every bike. The Stout hub here shown in an OEM application

The Specialized FATBike wheels are built around a 135mm QR „Stout“ front hub and a 190mm QR „Stout“ rear hub. There are no other hub sizes available at the moment. Same is for the axles: while in their OEM applications Specialized has a full range of QR and through axle combinations as well as a 150mm front hub available the aftermarket product is currently limited to quick release.
The good news: the cassette body can be converted to a SRAM's XD driver so you can go with a 1×11 application.

The technical stuff

Alunippel, Unterlegscheiben, riesige Löcher und keine "Tubeless-Rille"

Aluminum nipples, nipple washers, huge cut outs and no „Tubeless-Grooves“

Specialized rims are a single wall alloy construction with huge cutouts. The spokes have an offset of approx. 38mm to compensate the hub width. This lowers bending forces on the hub flanges and nipples. The latter are made of aluminum as well.
Spokes are double butted stainless steel.
The front hub is equipped with two cartridge bearings; its rear pendant comes with four cartridge type bearings plus an aluminum cassette body to lower overall weight. The latter can, as said above, be swapped against a SRAM XD type version.
Both hubs are compatible with 6 whole brakes disks only.

Sizes and weight

Rim width (inner) 86mm
Rim width (outer) 90mm
Front wheel weight ~1.250 gram
Rear wheel weight ~1.410 gram
Front hub 135mm / QR
Rear hub 190mm / QR
No. of spokes F/R 32/32
Cassette body Aluminum, 10 speed or SRAM X type
Price 449,- Euro (XD conversion kit 99,- Euro)

Look and feel

Gebürstes und eloxiert: die FatBoy SL Felgen

Brushed and anodized aluminum: the FatBoy SL rims

The Specialized FATBike wheels leave a good overall quality impression without pretending to be highly precious or sophisticated. The anodized surfaces of both, rims and hubs are what you can expect for the money: robust and lasting but not particularly beautiful. Their weight-to-stability ratio however is outstanding: it is pretty hard to bend the wheels and after 2 years of tough riding we never had to true any of our wheels. If you have to do you will definitely benefit from the nipple washers. A very high quality detail! The bearings run smooth and easy when new but become a bit harsh after a while.

Kritsch: die sehr dünnwandigen Felgenhörner

Critical point: thin-walled FatBoy SL rim edges

The very lightweight rims plus aluminum nipples (which come in black, unlike shown on some of our pictures) keep the critical rotating mass low and support good handling and strong acceleration.
Their width of 90mm makes the tire pretty wide as well which might negatively impact handling and overall rolling resistance.
However the very thin rim edges (approx. just 1,7mm wide) are the only real downside the Specialized FATBike wheels have. Whenever roots or rocks punch your wheels the rim edges eagerly bite trough any type of tube we ever tested and are prone to be bent.


Schwer abzudichten und bietet keinen zusätzlichen Halt für den Reifen: die FatBoy SL Felge

Hard to seal it off and has no edges that hold the tires in place: the FatBoy SL rim

25%. Single wall construction and huge cut outs make it hard to seal the rim. The rim well is plain, there are no grooves to secure the tires in their position. This might cause the tire to snap out of position and loose air in hard corners. We heard about some guys who ride their FatBoy SL wheel tubeless but the rims are not really prepared for that kind of use.

Pro and contra

Stout Hinterradnabe

Stout rear hub

+ very good value for money
+ great weight-to-stability ratio
+ lightweight rims for good handling
+ good build quality in its details

– sharp rim edges need extra attention
– hard to install tubeless
– strongly limited compatibility

So what?

1,4 bar. Und keins mehr! Sonst...

1,4 bar. That's it! Don't dare…

Thumbs up! The Specialized FatBoy SL FATBike wheelset is a great way to upgrade your old FAT brick and boost handling and stability – IF you belong to the lucky few who own an oldschool 135mm/190mm QR FATBike. To fully unlock their potential Specialized should offer the FatBoy SL wheels in the full range of today's applications. As wheels are very solid and offer great value for money more riders might choose them for their FATBike.
If we had a wish how to improve this great wheelset it would be this one: beef up the rim edges and blunt them a bit. Also a pair of grooves within the rim well would support tubeless application.
The rest is what we like the most: a lot of wheel for the buck!

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