Low Watts when climbing

I am noticing a major problem keeping up my watts when I am climbing on Zwift. On the flats and short hills, I have been normally riding around 180-210W. My FTP is currently 188. The other day, I did the Mountain 8 route on Watopia and went up the Tower Climb. This was torture from ground level, all the way up to the pass, and then onto the tower, all the while it was nearly impossible for me to maintain 150W. I refused to give up and finished the route 20 mile ride, and 2200 feet of elevation. My average speed was a pathetic 9.8mph! I felt absolutely destroyed at the end of the ride, worse than I have felt doing a century in the real world.

I am no pro rider, nor am I a speed demon, but I did 6 real world centuries last year, including 2 100 mile gran fondos, one with over 10,000 feet of climbing that featured category 2 and 3 climbs. Nothing I did in the real world was as tough as that Watopia pass/tower climb. I live in an area with hills, hills and more hills, and a typical ride for me will feature 2000-3000 feet of climbing. I have a hill around the corner from my house that has sections of 19-20% and 13-15% for stretches. This is something I can climb on a regular basis (sometimes doing repeats) without feeling like I have been through a war afterwards.

At someone’s suggestion, I lowered the training difficulty. I had it at the default of 50%. Here is something else I don’t understand. At 50%, the 13% Tower Climb should have felt like 6.5% to me, right? Absolutely no way. It felt like 13%.

So I lowered it to about 35%. I did 2 London loops last night with the Box Hill climb. No improvement. Much easier hill vs Tower, but the same results. I just can’t produce the Watts and it feels like I am riding in quicksand. I was doing a race, and people just passed me by like I was standing still. Again, I don’t think I am a special rider, but I am not that slow.

I have a Wahoo Kickr Snap smart trainer.

Any help would be appreciated.



It could be the Snap or it could be your low FTP. However having previously owned a Snap and having no joy getting accurate power out of it, it could easily be that. What I found with the Snap and the replacement Snap (after I exchanged it) it was power was way off what my power meter reported e.g.

150 watts on Snap = 120 watts on power meter

180 watts on Snap = 180 watts on power meter

200 watts on Snap = 240 watts on power meter

250 watts on Snap = 350 watts on power meter

300 watts on Snap = locked up the back wheel.

So the Snap was applying far too much resistance and it got worse as the power target increased. No amount of spindowns / advanced spindowns could do anything. I eventually got a refund and now ride a Hammer. Power is fairly cose to my power meter.

Wahoo support when they could be bothered replying to me were appalling and blamed my power meter. Well I have a new power meter and power is the same as the old one plus both were close to the Hammer’s power.

i was having trouble with too low of watts on a snap, and it was actually due to wheel slippage.

use the wahoo app to do a spin down, and make sure the spin down time is in the 15 second range.

mine was in the 25 second range (which means i needed to tighten the knob). after getting it into the 15 second range, my watts went up by 30ish, and everything just felt better. i was toast trying to get to 200w before this, and now i can hit 350w if i put in some effort.

if your snap was too hard to pedal, though, that could be a different issue – a spin down might help, but it also could mean something is wrong with your snap. at the very least, unplug it, reboot your computer, then turn them back on after 5 mins of downtime.

I just did a spindown on my Kickr Snap and it took 15.5 seconds.

Wahoo recommends that the spindown be approx 10-12 seconds. They also recommend tightening the wheel 2 turns before running your calibrations.

I had some issues with power and these went away when I modified the insides of the SNAP. I moved the sensor closer to the flywheel and I added more reflective tape on the flywheel.  However, doing this will void your warranty so if possible you might try returning the unit.

I’ve just bought a Snap and signed up to Zwift and I’m struggling to accept the data I’m getting from the Snap on my Zwift recording.

I did a 65 minute find tonight, peddling hard for all of it. Zwift tells I covered the rather feeble distance of 20km in the hour which just can’t be right as I was going balls out for the entire session. 

I also noticed that on some parts of the ride I was doing as little as 2Km/hr and at other times 80km/hr with no apparent difference in effort.

I may well not have the Snap calibrated properly so any advice on how to do this is appreciated. 

I was using a Garmin Edge 1000 until yesterday when it died (the second one to do so in under two years!). Like someone above, I have the power turned right down on it (to about 20%) as at 50% I could hardly turn the crank! 

I’ve got ERG on when recording in Zwift.


I have the same issue with a Tacx Bushido. Very, very, frustrating.