trainer trouble

About this time last year in the depths of a British winter I decided it was time to go Zwifting. However before you can run Zwift you first need a smart trainer so the research started. I very quickly decided that I was not going to spring for an expensive direct drive trainer, I felt the money would be better spent elsewhere, so it was the current crop of wheel on trainers that was my focus.

After a while I decided that the Wahoo Kicker snap was the best of the bunch. It is a robust unit, easy to set up and good features and ride quality. Just over a year later I still stand by that decision, but you need to be aware that I am on trainer number 4, the other 3 having been returned faulty. If you want to know how I got here, then read on.

Trainer No 1 was a first generation Wahoo Kicker Snap and all seemed fine initially. I was running it connected to my MAC via a Garmin ANT+ dongle that also connected to my Garmin heart rate strap and cadence sensor. I did notice some issues with the signal dropping out to the MAC but initially it wasn’t a major issue. However as I got more accustomed to the trainer and Zwift and pushed my workouts harder the signal dropouts became more of an issue. Clearly something wasn’t quite right . . .

Thinking that the issue might be the distance between the ANT+ chip and my sensors I bought a 3m USB extension cable so the ANT+ chip could be right next to the trainer, but still I suffered drop outs.

About this time I also started to notice that if I just controlled the trainer with my iPhone as I sometimes did to do a  Spindown Calibration, there did not seem to be any issues with the signal. So this made me think that the Kicker Snap was fine and hence the problem was with Zwift.

So I contacted customer support at Zwift. I was having other issues with Zwift at the time  and was in email correspondence with their technical support team so I thought I’d ask them.

We went though the usual diagnostic questions; are there any other strong ANT+ transmitters near by? Are you sitting on your microwave oven? Do you live next to a military radar base?

Eventually they put me on to a very useful web site called ZWIFTALIZER. If you have any Zwift issues you need this. It can analyse your Zwift LOG files and crucial provides data on the various ANT+ signals your computer is getting. I saw some interesting Data;

zwiftalizer 2

The data connection was quite terrible with lots of drop outs from all of the sensors and  the signal from the Kicker was especially poor, the data connection was failing about 50% of the time. The data connection from the cadence sensor and heart rate strap whilst still not perfect was much better. I thought this rather strange, how could the signals from small battery powered devices be better than that from the mains electricity powered kicker?

It now made me suspicions that there was a problem with the Ant+ signal from the Kicker (remember the blue tooth signal seemed just fine)

So I passed the data and details of my set up to Wahoo customer support.  They suggested that the 3m long USB extension cable might be too long and the problem might be signal loss in the cable. I had not considered that so I did some tests with a 2m cable and a 1m cable. Here are the numbers;

Heart Rate Strap vs USB Cable Length

3m – Rx Fails 23%

2m – Rx Fails 5.6%
1m – Rx Fails 1.2%
Cadence Sensor vs USB Cable Length
3m – Rx Fails 10.98%
2m – Rx Fails 1.6%
1m – Rx Fails 0.95%
Wahoo Kicker  vs USB Cable Length
3m – Rx Fails 48%
2m – Rx Fails 40.33%
1m – Rx Fails 41%
Looking at the data from the cadence sensors and heat rate strap you can clearly see that signal quality is severely affected by cable length, shorter cable giving a marked reduction in signal failures.  The conclusion here is that a 1m extension cable is enough. A 2 or 3 m cable may get the chip closer to your sensors but any improvement in radio signal transmission is out weighted by signal loss on the cable.
The other conclusion was that the ANT+ signal from the kicker was clearly rubbish. Changing the cable made no difference to the signal quality.
Faced with this data Wahoo agreed to a replacement Kicker on the spot.
Now at this point I was jolly glad I had bought the Kicker from a bricks and mortar shop, Sigma Sport in Hampton Wick, UK as it happens. The Kicker is a big beast in its box and having to arrange return postage to an online retailer would have been a real pain.
Wahoo contacted Sigma Sport directly to confirm that the unit was faulty and should be replaced and so one evening I stopped by the Sigma Sport store and they had unit Number 2 ready for me.
Unit Number 2.
Well this unit was no better, in fact it was worse. This was another first gen unit and the signal strength issue was exactly the same. I can only conclude that the first gen units have a weak Ant+ transmitter in them. But also this unit was mechanically defective. The roller was not on straight so the whole thing vibrated as you rode it. So after another trip to Sigma Sport it was on to unit Number 3
Unit Number 3.
This was a second gen unit and Wahoo have clearly upgraded the Ant+ transmitter as the signal strength was spot on with almost zero transmission failures.  See below for the equivalent Zwiftalizer data and look at the difference.
zwiftalizer
However before I checked the Ant+ signal I had discovered another problem. After setting up the trainer and mounting my bike I climbed aboard and almost fell off. Something was not right. Taking a step back and looking at the bike the problem was clear. The bike was not straight. I checked I had everything set up correct but for some reason the Kickr frame was not true and level. Since there is no way of adjusting it other than placing a block of wood approximately 2cm thick under one of the legs there was nothing for it than another trip to Sigma Sport and unit Number 4
Unit Number 4
I am pleased to report all is well with no 4.
Great Ant + signal
Not wonky
no vibration
Oh yeah!
So to go back to my opening statement, I still think the Kicker is a great trainer but clearly Wahoo have not got it quite right. If you buy one, I recommend you buy from a bricks and mortar shop and get them to set it up and test it before you take it away. The vibration and alignment issues indicate that quality control at Wahoo is not where it should be.
Also don’t be tempted to buy a second-hand first generation unit, the ANT+ unit is not up to the Job. I see wahoo is also selling reconditioned 2015 Edition units on their website at a substantial discount over the 2017 model. Given the issues I had with the ANT+ unit on these earlier models I would recommend you stay well clear.
I would also say that throughout this experience the customer service from Zwift, Wahoo and Sigma Sport has been excellent and I am very grateful for their help.
Now for a go at The McCarthy Special . . . .

Leave a comment

Blog at WordPress.com.

Up ↑