Flux line is confusing

New trainer time…I can get a Flux for 25% less than the Flux S - which i understand is basically the same. Then i noticed there is a flux 2.

Is there any compelling reason to buy a Flux S or 2 for RRP compared to a Older “regular” flux for 25% discount?

The original Flux is now Flux S.

Not sure of any mechanical or tech differences between the S and 2, but the 2 will accept long derailleur cages, whereas the original Flux and S will not.

1 Like

Flux S - slightly tweaked internal gubbins. Call it the Flux 1.5.
Flux 2 - an upgrade. Can simulate steeper hills; has better wattage floor; quieter; as @handynzl says, can accommodate different hardware

1 Like

Flux S = Flux, plus mechanical change to allow more room for long-cage dérailleurs. Unless you have one (a long-cage), no significant difference.

1 Like

The S does have the long-cage change.

1 Like

Flux is the original unit. Can’t accept long cage derailleurs.
Flux S is tweaked Flux. Can simulate steeper gradients and higher max power ceiling. Internals are apparently slightly different.
Flux 2 is new unit. Can simulate even steeper gradient, and higher max power ceiling again. Is apparently slightly more accurate, and the internals have been beefed up.


Thanks all, So given this is TR, and there are no hills to simulate, and i have a regular derailier - any reason for Flux 2 over the old Flux given its much cheapeR? i also use a quarq, so don’t care about accuracy.

On another note it seems the flux 2 cannot work with trainer road using bluetooth according to Dc Rainmakers video on Friday. I’m sure it will be fixed. Kind of lame though considering the trainer has been out for 2 months in Europe.

I ummed and arred over much the same choice, eventually going with the Neo 1 at 25% off.

I almost went Flux but eventually I will want to put the mtb on it so the derailleur size was a key factor. That and being really quiet!

GPLama broke 3 Fluxes in his initial reviews from 2? years ago, but one would think end of line stock are bug free. For the record, his Neo testing also resulted in a grinding of the magnets, so even the Neo isn’t without its issues.

What’s the worst could happen? Gets replaced under a warranty and you end up with a Flux S as there are no more Flux 1’s?

Can you justify that you’ll use it? It’s not just a fancy bike stand? If you went “yes…no…” to that, then pull the trigger mate.

I would recommend either upping to a discounted neo 1 or going elsewhere. I am currently waiting for tacx to come up with a warranty solution for my second broken flux. both broke the exact same way, started squealing and unable to hold target wattage steady. Second unit only lasted 16 rides before starting to squeal.

If you are constrained by budget here’s my understanding of the differences.
Flux S - new body to accommodate long cage derailleurs, slightly tweaked material internally to increase wattage floor control but not much different.
Flux 2 - New internals with a larger flywheel to simulate bigger gradients and have a lower wattage floor.

While the wattage floor and gradients sounds insignificant for TR, in my experience the Flux was a PITA. It couldn’t control precisely below 150w so in recovery intervals I found myself having to change gears and alter cadence to hold a 40 or 50% recovery interval. Vice Versa, it couldn’t hold max wattage in a low gear so I would then have to change gears up until I found a gear that it would comfortable hold 90-120% intervals.

I’m now hoping tacx will either refund me or replace my flux with a flux s so I can sell it and buy either a kickr or neo 1.

I agree with trying to find a Neo 1 if you can. I had 2x Flux and 1x Flux S fail within a total of 6 weeks. There’s some great deals on the Neo and it really is worth the extra money if you can stretch to it.

1 Like

Aye, this is my bug-bear at the moment. If I wanted to do 60 RPM it would be OK, but I like to spin between 85-95.

Also my Flux S is starting to squeal until it warms up.

I had this issue (Flux S), but mainly because of long gearing (2x7, shortest was 39x21). I updated my trainer bike to 10sp, and lowest is now 39x28, no issue - I can go below 80W at 90 rpm.

I am another user that has had the Flux (original) fail multiple times, I would look at either their Neo (super quite apparently) or another brand/option.

hard trainers are good to find if Wahoo and Tacx are out!

Already returned my Core and seems like Wahoo are having mass QA issues.

Unfortunately my equivalent is 34x25 :angry:

That’s pretty close to my 39x28 - you should be able to spin below 100W easily.