Juggernaut Ultra FS

I'm considering purchasing the Juggernaut Ultra FS. There seem to be a lot of "Juggernaut" variants, and since they're different frames I'm not sure just how much experiences are shared. Some questions:

1) Standard seems to be the 26"x4" fat tires. In general, I'm more a fan of the 27.5"x3" (aka "Plus") size. I'll be both on and off road. Pros and Cons of each? I assume the gears are the same for both sizes, so what does that do for overall gearing? I assume the Fat tires are smaller in circumference, so the low gear is a bit lower than with the Plus tires - conversely the high gear with the Plus tires is higher than with the Far tires? Correct?

2) The Tektro Dorado E710 (discontinued I believe) is current standard. Seems a decent hydraulic brake system for a two-piston design. There's a $300 upgrade to the Magura MT5E - anyone have any experiences thoughts on the difference? I assume the 180mm discs are the same for both (and I might want to upgrade to 203mm discs in the front anyway).

3) Mikey's EBR review mentioned that "it would have been great to see some even wider hub spacing and perhaps extra gussets to reduce frame flex." This was May 2019, so I believe he was riding the latest frame geometry. How bad is the frame flex?

4) I know this is somewhat personal preference, but thoughts on the Wren vs Rockshox Bluto front fork - especially with the Plus size tires?

thanks in advance - I'd love to hear about anyone's experiences with this bike as well.


Active Member
the outer diameter of the 26x4" and 27.5" x3" are actually almost the exact same, so similar gearing/speeds assuming similar rolling resistance/tire compliance.

Tektro Dorado and Auriga brakes are fantastic and I doubt you will ever need more stopping power than these provide. The magura "upgrade" is for preference option and IMO overkill.

Frame flex issues, I didn't find any whatsoever on the latest generation, I test rode it in March 2019 and put up a review on reddit. Vast improvement over the previous generation tho.

Forks: Wren is a way, way better fat bike fork than the Bluto. Wren and Mastodon are the two best options right now and anything else can't touch em.
Thanks, Deafcat - good to know about the frame flex. Buying online is great and all, but for things like this, having the ability to test ride, or at least a window for return (like Evelo), is the best way to go.

The bike is heavy, though - 73 lbs and that's not even with the big battery. Configured as I'd want, the bike is pushing $5K, which is serious money. I did get to test ride a Luna Apex. Very powerful, full suspension and carbon frame. Probably convinced me I want the 27.5" Plus tires instead of full-on fat. At say 70 lbs with the battery removed, it's 10lbs over what my hitch mounted bike rack can handle. So, I may need to keep looking.

And, of course, I want to do the silly thing of putting a rear rack on the bike. There are some racks that mount to the seat post, which should work since I won't be putting much weight in there (spare tube, patches, mini-tool, a jacket, etc.), and there are some racks that mount to the swing arm. R&M's Delite is full suspension with a rack, but it has less power, frustrating Bosch limitations, and is even more pricey.

Anyone else have experiences on the Ultra FS they'd be willing to share?


Active Member
Most full suspension ebikes are quite heavy, this is a function of adding multiple shocks and associated extra parts... Some lighter ones do exist but they tend to be well over the 5 grand mark.

Biktrix does have a special rear rack for the FS, you could inquire about that... It is designed to mount entirely on the rear swingarm.

Far as weight goes: I stick with Hardtail bikes to eliminate several concerns (increased weight/complexity/maintenance). Fat and plus sized tires, combined with all the other technical improvements, have made hard-tails the new full suspension (and rigid bikes the new hard-tail!)


Well-Known Member
My Juggernaut rigid weighs 52 lbs (without battery) stripped of fenders, crappy front fork, racks.


Active Member
I think for most riding conditions, Tektro Dorados are very good brakes for the price point. If you ride your bike over over 30mph regularly upgrading to big rotors and 4-piston design helps with providing more braking power and modulation. Magura MT5 is what I eventually did on my fat bike. I think it makes sense for the front to be upgraded, but in retrospect, I could have just left the 2-piston setup on the rear as it didn't have any issues locking up the wheel with the Tektro brakes. The other downside of the Magura stuff is the cost of brake pads, unless you buy them in multiple sets from a German vendor, expect to pay $25-30 per pair of brake pads. For disc brakes I tried a few including Tektro, Magura, and Shimano. The Shimano IceTech RT-86 rotors are what I've been running. The two piece design makes them a little less prone to bending compared to other 203mm rotors.