Beats me.
Probably it is more convenient to fix things up and make it work, instead of sending a 15kg, huge box back and forth?
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I’ve had three trainers from them now. The third one was apparently upgraded with the new bearings, or whatever their “upgrade” means - but it vibrates worse than the other two and has now developed a clicking noise.
That, and they lost the original trainer they originally said they were going to upgrade (which had the least amount of vibration..)
Pretty much over it.
Okay, since there’s some discussion over disassembly and replacing parts, I figured I’d share my techniques. Warning, I’m not affiliated with JB in any way and am a geologist, not a mechanic, so please don’t hold me responsible for any damage if you decide work on your own trainer lol. I also wrote this all in one go, so I apologize for spelling and grammatical issues.
Tools:
Dead blow hammer (2 lbs/1 kg), drift pin/punch (7/16 inch or ~11mm), spanner wrench, 3-in-one oil, loctite blue (#243), #2 phillips head screw driver, ratchet with 10mm socket, and c-clip pliers
Removing belt:
Remove bike, unplug trainer, remove six #2 phillips head screws holding side plate on, and set aside
Slide two fingers behind belt and begin to pry/twist the belt towards the edge of the flywheel pulley.
While continuing to apply pressure to the side of the belt with your fingers, take your other hand and slowly spin the drive pulley (the big carbon fiber one) counter clockwise to walk the belt off of the flywheel pulley.
Almost off – you want to slip the belt off the flywheel pulley rather than have it slip off the tensioner pulley (bearings) so the spring won’t release all at once.
Removing flywheel and shaft:
Pull belt and tensioner spring off and set them aside. Use your 10mm socket and ratchet to remove the flywheel pulley flange bolt. Hold the flywheel from the backside with your other hand to keep it from spinning while you remove the bolt. Set the bolt aside once removed.
Gently pry the flywheel pulley off, note there’s a key that fits in a slot formed by indentations on the flywheel shaft and pulley. The pulley looks pretty gnarly, but that is mostly rubber dust, oil, and some material transfer from the shims that I’ve added to align the belt on the inner groves.
Set aside the pulley and key.
Use gentle pressure on the end of the flywheel shaft to push it through the bearing. Mine has occasionally had a bit of galvanic corrosion that needed a bit of tapping with a drift pin and deadblow hammer to free. Try not to use too much force here because it is possible to “mushroom” the end of the shaft making it even more difficult to free. It’s also possible that pounding too hard will compress the bearings against the races and cause pitting (i.e., brinelling). A possible technique to prevent this would be to reinstall the flange bolt and tap it with the drift pin/deadblow hammer rather than pounding directly on the shaft.
I’ve found that once the corrosion is broken, then the shaft slides pretty easily and can be pulled from the flywheel side by hand.
Here’s the end of the freed shaft. Note the light ring of corrosion, likely caused by a galvanic reaction between the steel shaft, steel key, and aluminum pulley. A light coat of oil (NOT GREASE) on reassembly helps prevent this in the future. A light buffing with scotch brite pad will remove the corrosion and ease future disassemble/reassembly.
Here’s the flywheel side showing the two pairs of coils and optical speed sensor in the middle (green board), along with the nachi 5202zz bearing. The optical sensor tracks the white/black pattern on the flywheel.
Removing/replacing bearings:
To remove the 5202zz bearing on the flywheel side, insert a drift pin through the pulley side and lightly tap with a deadblow. Tap on one side of the bearing once, then rotate the drift pin to the other side and tap once again. You don’t want to hit the same spot multiple times because that will twist the bearing and make it harder to remove. Also, hard pounding will definitely trash bearing or reduce it’s lifespan substantially. Note the tensioner pulley assembly is out of the way in the picture. It’s removal is described below.
If you tap slowly, you can work the bearing out enough to pluck it out with your fingers. Alternatively, if you hammer hard, the bearing will probably pop out on its own.
In addition to the bearing, you’ll also find a bearing spacer tube that helps set the preload between the flywheel and pulley side bearings. Go ahead and pull it out. This picture also shows the optical speed sensor a bit better. The actual sensor is that black box on the green board if I’m not mistaken.
To get at the other flywheel bearing (nachi 6002zz), use a spanner wrench to remove the round spanner nut. This was pretty tight on mine (probably more galvanic corrosion/rubber debris), so work carefully and it will unscrew. This spanner wrench just happened to fit, and is one that came with one of my angle grinders. I found an adjustable spanner wrench at the hardware store that works too. Use light oil on reassembly, and you won’t have to put as much pressure on next time you need to unscrew the nut.
With the spanner nut removed, the tensioner pulley assemble should slide right off. You can access the two additional nachi 6002zz bearings that serve as the tensioner pulley by removing the c-clip with c-clip pliers.
To remove the last flywheel bearing (the 6002zz behind the tensioner assembly), tap at it from the other side as before using a drift pin, or alternatively use a bearing puller. This picture shows how I use the drift pin to evenly distribute pressure along the inner race.
Lastly, remove the wave spring in the flywheel pulley bearing housing.
This wave spring applies preload to the 6002zz bearing (along with the bearing spacer and pulley flange bolt).
So there you have it, the mechanical guts have been mostly disassembled. Top row shows the spanner nut, tensioner pulley arm, two 6002zz bearings, and c-clip. Bottom row shows the flywheel and shaft assembly (note the small spacer still on the shaft, this is very important for accuracy/resistance), 5202zz bearing, bearing spacer tube, wave spring, 6002zz bearing, flywheel pulley, key, and flange bolt.
Reassembly:
Give all moving parts a good wipe down to remove any rubber debris from the belt, dust, or corrosion. Contamination is one of the main causes of bearing failure.
Pop the flywheel bearings back into the housings, being sure to include the bearing spacer tube in between and wave spring behind the pulley side bearing. I use a light coat of oil in the bearing housings and to aid with future insertion and future disassembly. If the bearings won’t slide in, you can tap them in being careful to keep the drift moving. Alternatively, a block of wood can be used to distribute the pressure and help prevent brinelling.
With the flywheel bearings back in place, I apply a light coat of oil (NOT GREASE) to the flywheel shaft and slide it back into place. Don’t forget the spacer at the base of the flywheel shaft.
Reassemble the tensioner arm assembly (put the two 6002zzs back in place and secure with c-clip) and affix it to the trainer using the spanner nut. Remember, use some light oil on the threads of the spanner nut to aid with future disassembly. Optional: Here you can seem some small shims that I use to push the flywheel pulley out a hair and align the drive belt with the inner grooves.
Pop the flywheel pulley key into the groove and slide the flywheel pulley into place over the shaft.
Apply a thin coat of locktite to the threads of the flywheel pulley flange bolt and toque to spec (~10 ft lbs, 15 Nm).
To reaffix the belt, guide it through the flywheel pulley and around the tensioner pulley (be sure to reinstall the tensioner pulley spring, hooks facing up). Then loop the belt around about 1/3 of the drive pulley and leave the rest slack behind the drive pulley, passing between the plastic shell and drive pulley.
Here’s a view from behind, showing the slack belt looped partly over the drive pulley and then routed down towards the space between the plastic shell and drive pulley.
Last angle from above, showing the routing of the slack part of the belt. Clamp the belt drive pulley where it wraps over the back using finger pressure.
Then, while continuing to clamp the belt where it loops off the drive pulley, simply rotate the drive pulley counter clockwise towards the slack end about 1/3 of a turn. The drive pulley will begin to take up slack and tighten the spring until the belt is wrapped around all pulleys.
View from the front, you can see the spring beginning to stretch as I rotate the drive pulley counterclockwise.
All done!
If there is any misalignment at this point on the drive pulley (and there usually is), just spin the drive pulley the opposite direction (clockwise), and it will usually work itself out. You can also use finger tension to guide the belt (as during belt removal).
Check and verify that the belt is correctly routed through the drive and flywheel pulley groves.
Reattach the side plate (6 phillip head #2 screws), reattach bike, plug in trainer, and complete a spindown.
The only major issue that I faced after reassembly is some bearing humming that sounds like a thumping at lower speeds. This always happens to me when the pulley flange bolt is not tight. Be sure to torque to spec and use loctite. I think there’s just enough play between the flywheel pulley and shaft (as a result of the key interference fit) to cause issues if the pulley bolt backs out.
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Thank you very much for taking the time to write this great guide. I shall be saving this for future reference!
My JBV arrived Jan 21st and I’ve been using it daily since. Things have been running pretty well up until this past weekend. I took the bike off the trainer for my first outdoor ride of the season. When I put the bike back on the trainer, I did a firmware update in the JBV app, and now I’m noticing resistance issues and I’ve had one drop out so far.
Before the firmware update, if I plugged in the trainer and started pedaling before connecting and starting a ride in Zwift, it would be easy pedaling with little to no resistance. Now it feels very hard to pedal until I actually connect and start shifting. Even when the ride begins on gear 8, there is way too much resistance, but as soon as I shift up or down it feels like the trainer wakes up and corrects the resistance, although the gearing still feels a little harder than it did prior to the update.
The drop out I experienced was near the end of a climb towards the end of the ZG25 Queen route during a race. I adjusted myself on my saddle which caused my cadence to drop for a moment, but the connection completely dropped. I was still pedaling but going nowhere. I was able to reconnect through the menu, but this was super frustrating during a race. I always connect to my iphone via bluetooth, because the one time I tried connecting straight to apple tv I lost connection. That was a few weeks ago prior to updating. I haven’t tried connecting to apple tv again since then because it’s not worth the risk of losing connection in the middle of a ride. But this recent drop out happened while connected to iphone via bluetooth, so it wasn’t a wifi issue. It’s only happened once so far, so right now I’m more concerned about the resistance issues.
Wow, thanks for the write up! I’ll probably try mine again at the weekend with a slightly firmer “tap” to see if that loosens the freewheel.
on my side everything seems to be going pretty well just problems with cadence in freewheel or it takes me a while to come to zero. I have not had any loss of wifi I am on the last update. my first concern was the power because the Assioma developed about 15/20w less on 300w and I had first blamed the Victory without really looking into the question of the Assioma and I concluded in the end that the problem was the Assioma pedals which were not well calibrated as a base because I did a static weight test and it was missing about 3% on each pedal. I did a competition on zwift and the Avg power of the Assioma 299w vs 304w jetblack. everything is back in order. I hope this can help someone who compares the power of well calibrated with a static weight of the Assioma because in my head I really think that it was super well calibrated since I bought them recently.
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The gears are feeling better now, but I’m still getting resistance when pedaling before starting a ride in Zwift. Once the ride starts, the resistance goes away and it feels like the usual 8th gear when starting a ride, but this never happened before the update. There was never any resistance on the trainer until I began my ride and started shifting. Has anyone else experienced this? I’ve made sure that my skewer isn’t too tight, but I can’t imagine that being the problem because before the update, my skewer was much tighter than it is now with no issues.
I noticed this last night when I tried to warm-up in the pen before a race. It felt a lot harder to get the flywheel up to speed. I’ve been on the latest firmware for a while now, but Zwift updated last night, so I’m wondering if it is something to do with Zwift rather than the trainer firmware.
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My trainer started on firmware 4.13 (received near the end of January) and has always had high resistance until the World loads and virtual shifting activates. It doesn’t cause any issues for me, and I figured that was just normal. It’s not like there is really a correct resistance level before we’re fully loaded into the World.
yeah it’s not a big deal as long as the resistance feels right once the ride starts. it’s still feeling much higher for me. i would normally use gears 17-19 on a descent. 20+ only on steep descents. i just finished a ride where i was in gear 13 and 14 on my descents. 15 was too much resistance which is crazy because normally i’d be in 15+ on flat or even a slight climb.
Once the race started could you still feel increased resistance? I’ve been running 1.85 up until today, but it still felt like the resistance was higher after the update. Even just pedaling on the trainer without Zwift open, it feels sluggish and hard to pedal, whereas before there would be no resistance until I started a ride in Zwift.
It’s hard to say really, as it was the Queen stage of the Zwift Games so it was an awful, hard race right from the start.
4.13 felt more stable to me. With firmware 4.15 I’m getting dodgy cadence and problems super tucking again. I’d stick with 4.13 if you haven’t already updated, until they release another update that supersedes 4.15.
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Yeah, sadly this seems to be the case. I held out on updating for a while, then finally made the change earlier this week. I’ve now had to power cycle twice to get Zwift to connect over WiFi and am seeing phantom watts when coasting downhill that prevent supertucking.
3rd dropout now since updating to 4.15 from 4.13 on Tuesday. This one was at the end of a ride. Powercycle and going back to the pairing screen seemed to fix it. I’m a little worried that this could boot me from a race.
Any way to roll back firmware?
I don’t think there is any official way to roll back the firmware. I think some-one managed it further back up this thread using third party software. Are you able to use Bluetooth instead of WiFi? That’s what I have been told to do by JB and I haven’t had a dropout so far.
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Thanks! Got the chasing milan-san remo race tonight. They boot you if your trainer isn’t connect so I guess bluetooth it is. Bluetooth has racemode right, or just wifi?
Going be crazy with bluetooth connections though. Let’s see, I’ll have the trainer, two controllers, heart rate monitor, headphones, and then my crank power meter to garmin for dual recording. Not to mention mouse and keyboard.
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Got the firmware rolled back! Thanks for the reminder.
Here’s the dropbox link for the 4.13 firmware (took a while to correctly transcribe from the images up in this thread):
And the firmware uploader for android:
Took about 1 min to upload, and immediately rebooted to 4.13. Interestingly, I know longer see an option to upgrade to 4.15. Wonder if they pulled it?
BTW, I’m up to 3,323 km on the trainer. It’s had its ups and down for sure, but overall satisfied. The price to features ratio can’t be beat, that is if you’re willing to do a bit of tinkering.
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