Juggernaut Duo 3 update with some warnings for big folks (read: fat and over 300lbs)

Bjaardker

New Member
Region
USA
Hey there everyone. I've got just over 100 miles on my Juggernaut Duo 3 and wanted to give a few updates. Just so we're all on the same page, a little bit about myself. I'm a mid 40's guy who is 6'0" with a 30" inseam and weighs 340 lbs. I used to be an avid recumbent rider (30-50miles daily), and wanted an e-bike to ease back into the cycling life.

1) With the 19" stepover frame and 27.5 tires I BARELY fit this bike. Riding is comfortable, but when I come to stops I've either got the stepover bar crammed into my crotch while I'm standing on the very tips of my toes, or I'm stepped off to one side with one foot on a pedal at the top of the crank and the bike slightly tipped over.

2) The RST Renegade Spring fork is clearly not made for the weight limit the bike is built to handle. Even with the preload set to full, I'm bottoming out the shock on the slightest of bumps. Just sitting on the bike the fork is compressed to over 50% of the travel. This is a major disappointment and I'm left to locking out the front fork and riding with no suspension.

3) The Cane Creek Long Travel Thudbuster seatpost suspension as sold by Biktrix comes with an elastomer meant for someone around 150-180lbs and has a max weight limit of 250lbs. When you go to the separate accessories page for the Thudbuster these weight limits are shown, but I just added it from the "build your bike" page and had no idea. I've since purchased the extra firm elastomer (250 max weight) and it's very comfortable and seems to be working, but I worry that I'm well beyond the weight limit and it will eventually break.

Other interesting tidbits and thoughts:
  • The battery screen in the display doesn't show any information, so there's no way to get details on the life and health of your battery and cells. I contacted Biktrix and they said that screen just isn't going to work and it's functioning as intended.
  • The kickstand is placed fairly far forward and and blocks the pedals from rotating.
  • Because of the way the SOC display works, I haven't found any way to tell if the secondary battery is working outside of removing the primary battery and turning on the bike.
  • Even as fat as I am, this bike goes like a bat out of hell and I find myself regularly cruising along ~18-20mph in PAS 2.
  • The throttle is fantastic for getting moving when you're sharing the lane with traffic and you were stopped at an intersection.
The issue with the fork is my biggest complaint at this point. Hopefully at some point I'll be able to save enough to replace it with something that will work for me.
 

Pulsar

Member
Region
USA
City
DFW
I have a duo 3 as well. Been happy with mine and had no issues. The stock RST front fork is not that great for its a spring type only and not air pressure or hydraulic type. I carry less weight so mine is adequate and rarely bottoms out so for my daily riding it’s good enough. If your running both batteries, turn the switch off on the external battery and you should see a slight voltage change. Ride for a while on the internal battery then flip the switch back on for the external battery and you should see voltage go up slightly as the dualizer manages both batteries so that way you have faith both batteries are in the circuit.
 

theemartymac

Well-Known Member
I'm similar to you in size and measurements, and you've certainly figured out the main points the hard way.

Now you might be able to just upgrade the spring in the fork as well. It's still an entry level fork, and you aren't going to make the overall fork any stronger, but you should be able to reduce and/or prevent the bottoming with a heavier/firmer spring and may even find you can noticeably improve the overall ride because the preload isn't maxed out and the sag is correct. Ultimately, upgrading to a mid-range air model will probably give you far more adjustment range as well, but primarily improve the bottom-out performance as compressing air has a naturally increasing spring rate (the more you compress air, the harder it gets to compress it further).

There is a chance your LBS won't want to touch a cheap fork as they aren't generally intended to be upgraded, but if you pop the spring out yourself and just bring it in, they may be able to measure and order a reasonably compatible firm model. Or you can do it yourself online, but you would have to find one with compatible dimensions and a 'firm' rate. Last option would be to shim the stock spring (ideally with a second bit of spring), which generally reduces travel, but pre-loads the pre-load so-to-speak, giving you more upward adjustment range on the pre-load dial. There are stories from the old days of guys using stacks of quarters to shim the top of the spring on the fly.

RST Fork Disassembly
 

Ninja_Surgeon

New Member
Region
Canada
I think the only way to get the "Battery Information" in Bafang displays to show anything is to use a battery that comes from Bafang. And they don't have much to offer for high capacity batteries which is unfortunate but a trade off to be made.