How Accurate is the Wahoo Kickr Snap
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- Опубліковано 23 лип 2024
- Let's compare power data from the Wahoo Kickr Snap indoor smart bike trainer to the 4iii Shimano Ultegra R8000 Precision Left Side crank power meter. In this video I will present power data from a few different tests including average power from 1 minute at 100 watts, 200 watts, 300 watts, and 10 minutes free-riding in Zwift.
Testing notes (for those who are curious). The Kickr Snap was warmed up for 10 minutes prior to performing a calibration spindown via Zwift. I am using a trainer tire and verified pressure was 110 PSI. The knob on the Kickr Snap was rotated two full turns after making contact with the trainer tire. The 4iii power meter was calibrated via the featured Garmin Edge 520 plus prior to testing.
I'm hoping I will be able to perform this test again with a dual sided power meter for a more accurate comparison, but for now the numbers are correlating well between the 4iii and Wahoo. - Спорт
Nice job. Thanks. Just received a new Snap a few days ago. First time as a recreational cyclist I have measured power. Could not believe how hard 200w felt! 190w FTP to start. I would think that power at the pedals is around 15w more than at the tyre. 5w drivetrain loss and 10w rolling resistance. Perhaps wahoo snap allows for this and adds it on. Will eventually get a stages left side PM or perhaps Favero Assioma . Then will run Snap off that for consistency on road and on trainer. I think as long as the snap is consistent, then it will help to boost power. Hopefully when I get Stages I will get a 10w surprise power boost!
I was wondering if the Kickr Snap does that myself, based on what I measured it appears to take the losses into account. Perhaps the spindown measures the losses at the tire and rear hub. But that should still leave 5 or so watts from the drivetrain. I started pairing my new PM to Zwift just so I dont have to run a spindown all the time but the Kickr Snap's power has been consistent as long as you calibrate often
I've been using a Kickr Snap for a little over 3 years. Initially, I used a road tire and I needed to use 2.25 turns on the knob to stop slippage. After I destroyed the road tire I bought I Vitoria tire similar to the one you have and found that I only need 2 turns. I pump the tire up to 100psi. Maybe I'm imagining it, but I think the slightly lower pressure and slightly few turns reduces wear prolonging the Kickr's life.
If you pump the tire up to the same pressure each time, rotate the knob the same amount each time and the ambient air temperature is the same then I don't see the point in calibrating frequently. If something changes, eg. replace something in the drive-line, or the room temperature is a couple of degrees different, it's probably worth doing. Even so, +/- 3% is a range of 6 watts per 100 watts (97-100-103, 194-200-206) which can mask minor calibration errors. So I don't get too picky about it. I'd rather spend the time riding than calibrating.
ps. tip for you: use a piece of tape, or something, to mark the "zero-point" where the roller touches the tire. That makes it easy to count 2 turns and position the knob in the same place each time.
The tape isnt a bad idea! I agree, id much rather not stop to calibrate :)
How about using the power meter on crank/pedal to pair with swift and control trainer’s resistance. I am not sure if this is a good idea or if it would make a ride easier/harder.
Hey great video! Do you need a cadence sensor to get on zwift if you have the kickr snap?
You don't need a cadence sensor, but it's a nice addition
Is the snap a quiet trainer compared to other wheel on trainers? Would you recommend a trainer tyre while using it to help reduce noise?
I have a video "how loud is the Wahoo Kickr Snap" you can check out. I havent tried any other whe on trainee so i dont know how it compares. Definitely recommend a trainer tyre to both reduce noise and save your road tyres from wear.
@@socalgravel thanks, I'll check it out. 👍
Did you check on Wahoo app whether firmware was updated and did you do a spin down on the app as well? Tyre pressure should be 100 psi and 2 and half turns of tyre resistance to stop slippage. I've found the snap a better option than belt driven smart machines as they tend to get too many problems
I set it up with a little higher (110ish psi) but its the pressure meter from my bike pump so probably not very accurate. 2.5 turns, and yeah just confirmed the firmware was up to date. Not tried the belt driven machines.
Do you think there is value of upgrading to a Kickr or Kickr core or would you just buy the Kickr climb and keep the snap?
Is it a good trainer? Can I ride 10+ on it? Is it worth the price?
So you think your weaker leg is pushing more power when rested than your stronger right leg? Sorry but that just doesn't seem right. I have the exsact same setup (Kickr Snap - 4iii Precision Left side) and exsact the same result. Kickr snap is reading lower from 10 to 20%. And I wouldn't trust its reading compared to 4iii. Here's why. You said correctly the kickr snap is the reading on the end of the power transmission and it should read a little lower but not anything 10 to 20% to quote one internet page.
''Experts say that overall drivetrain power loss is approximately 2-3%. Therefore, keeping the math simple, if you applied 200 watts to your pedals, the pedals would see all 200 watts. The hub however would see roughly 194-196 watts.''
Personally, I think it just a poor design they could add average power loss from the drivetrain to match the power that it's coming from the power meters from the front of the drivetrain, the whole shebang about turning knobs two or two-and-a-half turns and 80 to 100 PSI just doesn't make sense if you're measuring 100 to 150 watts there shouldn't be any difference no matter what tire or pressure you use, the important thing is that there is no slippage because Kickr snap is reading/measuring the speed of the flywheel the power number comes from the calculation.
Why I know Kickr Snap is the wrong number, let's say you're in erg and have 80 cadence and 150 watts when you shift to a higher gear and up the cadence, KIckr will adjust the resistance and you'll still have 150 watts maybe a little more for a very short period but on your crank, you will see correct and instant power spike. and therefore you have power loss on your trainer. So if you have a session with lots of intervals and cadence changes etc the power difference will be higher.
What really worries me is how GP lama tested snap and got all those numbers much closer 1 to 2 watts ( around 300 watts) for 20 and 30-minute power.
I will do more tests but it could just be a faulty unit.