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Old 12-04-11, 05:28 PM   #1
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Problems with Trek FX+ intermittent power fluctuations

I am having problems with my Trek FX+ WSD. Yes, I have taken it to my authorized Trek dealer that sold me it, it is there now. I have felt that intermittently, the bike gives me resistance to pedaling, and/or the level of power assist provided at the various levels is inconsistent. Today I brought my bike in because it seemed to be not giving me that "kick" at level 3 and 4. The shop pointed out that the tires were low, but after pumping them up properly, it still didn't feel right. They test rode it and said they felt the assist, I agreed, but told them the assist was not up the level it HAD been at. This problem also happened 3-4 months ago, and they upgraded the software and the problem disappeared. Now I am thinking that the disappearance of the problem was just a coincidence, and the problem is really mechanical and not software related. I just have this gut feeling that the bike is not functioning consistently. I am going to call Trek on Monday to see what they have to say, but interested to hear about other people's experiences so I can alert my bike shop

One of the downsides to having a bike like this, is that there aren't a lot of them out there, this limits the amount of data that has been gathered on them, obviously, and it also means that your bike shop probably hasn't sold dozens of them. I live in the Bay Area, California, where there are lots of bikes and lots of money, the bike shop I go to is one of the more popular ones, and still, I learned today that only about 10 people had bought FX+ bikes. Whats frustrating is that I feel like because of the lack of experience, there are undiagnosed problems.

I am enjoying the bike when its working well, but sometimes I wish I had waited for all the bugs to be worked out.

Thanks, Anna
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Old 12-07-11, 03:35 PM   #2
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Good luck, Anna. I had a problem with spokes breaking & I went through the same thing. No one really knew what was going on. I emailed Trek with my issue & got some helpful responses from their customer SErvice department. The local shop was responsible for fixing it, but having talked with Trek, I was able to go in with a bit of knowledge into the situation & some likely root causes.
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Old 12-07-11, 11:21 PM   #3
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Does your ebike use BIONX system from Canada?
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Old 01-08-12, 12:35 PM   #4
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I have an FX+ and put over 7000 miles on it. There are 2 reasons why this ishappening.

1. The rear weal is not being tignented with a torque wrench to 40Nm.

2. When you had a firmware upgrade the BionX system runs in 3 modes. Thishas nothing to do with the level of asissit from 1 to 4. The old firmware onlyhad 2 modes. When I had the Trek dealer upgrade the firmware I had the sameissue as you. I am not sure of the correct terminology but basically the 3modes are

1. High Assist

2. Regular Assist

3. Low Assist

By default Trek sets it to level 2(Low Assist). You should have them changeit 1(High Assist).
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