Gym123456

Hi-

New member, was looking for some info about fluid trainers and maintenance. I have a Blackburn TrakFLuidTrainer that I got from a friend and recently started using it as part of my knee rehab. While I was riding with a YouTube climb video, I noticed that as I pedaled harder in higher gears, the resistance increased drastically and it almost felt like bad ball bearings were causing it, but when I pedaled slower, it smoothed out and was normal until riding harder for a few minutes, when it started again.

Do fluid trainers have a maximum speed? The bike I was using is a Giant Sedona with 26" wheels and I wasn't pedaling exceptionally fast. Does anyone know what kind of oil is in these? No signs of leaking, the bike wheel and trainer hub turn freely/smoothly and the didn't feel heat sink on the trainer hub only felt warm, not hot.

Thanks in advance.

caloso

Fluid trainers are intended to increase resistance at higher revs, in order to mimic the aerodynamic effect of riding outside. https://www.cycleops.com/post/blog-1...istance-curves



If it ramps up gradually, and then much more sharply, then it's probably working as intended. If there's an abrupt change, then something may be wrong.

Gym123456

Right- I understand what they do and a bit of how they work (like a torque converter in an automatic transmission, it doesn't resist until the speed/pressure increase) but when it slows, it's drastic and happens after riding at a particular speed for over a minute. It also includes a vibration but as I posted, the bike's wheel and the trainer's hub spin smoothly. I called Blackburn and they no longer make trainer & their knowledge base isn't maintained, so the person on the call didn't know exactly what this problem could be.

Thanks

Feelgood1

Try reducing pressure on freewheel

Gym123456

OK, I have varied the pressure on the tire, no change. I removed the flywheel assembly from the base and opened it- seems as thick as 80-90wt gear oil and smells similar, too. I called Jensen Bike USA and the person who answered checked with some others who work there- they said it's 'thermodynamically neutral medical grade silicone fluid' which is also used in Kinetic brand fluid trainers. Does anyone know anything about the viscosity? Waiting for a callback form Kinetic.

Iride01 

Was your friend having that problem? Maybe that's why they got rid of it. At any rate, your friend ought to be able to tell you it what you are experiencing was normal for when they had it.

Gym123456

Not sure he actually used it, but I'll ask.

Gym123456

Well, I found out what is used in Saris and Kinetic trainers- Thermodynamically-neutral medical grade silicone fluid. Great- where do I get this?

burnthesheep

I mean, local to me there are 3 or 4 fluid trainers for $75 or less used on Craigslist. That's how I got mine years ago. Sometimes instead of deal with selling on Craigslist local bike groups someone may give one away they are tired of sitting in a closet.

They're a dime a dozen and mostly bomb proof, until it isn't. Then it's largely disposable and not worth your time IMO.

If you're digging into replacing fluid or bearings, you could go rake leaves for a few hours of your time instead for $10/hr and make up the money difference to buy a "known good" one off someone on Craigslist. Just saying that to mean that your time is worth something also.

Gym123456

I don't like the 'everything is disposable' mentality and since this doesn't have the above mentioned silicone, it's likely that someone changed it. Maybe someone sells some other kind of oil based on similar BS that's believed by people who like stupidly expensive audio cables- until I talk to my friend who gave it to me, I won't know.

I'm 64, I have a bad knee and two bad shoulders- I'm not raking anything.

I have seen a lot of trainers in local ads, but unless I get a chance to try it, I'm not buying anything. Besides- I like solving problems and fixing things.

Iride01 

Still not sure you have a problem with the trainer. What you describe seems normal. But I'm not there to experience it myself, so I'm not going to say for certain.

Gym123456

Just to be clear, it's fine for awhile and then, it becomes more difficult to turn the impeller and it feels almost like I'm on a washboard road or path. I had a wind trainer before and I hated it, but only because it didn't have a flywheel and it was noisy as crap. All I read and hear about fluid trainers is that they're the most realistic and of the non-stationary bike type, they're the most quiet.

I asked Jensen Bikes, Kinetic and Blackburn- the only one who told me anything useful was Jensen, but they didn't know the viscosity or where to buy it. Blackburn doesn't have any old info and it seems that a lot of the people who work there now are fairly new. Kinetic verified that it's Silicone fluid, but couldn't/wouldn't say anything about the viscosity.

Maybe it's time to call some plastic surgeons.......

Iride01 

<grin> If that is to discuss silicone then maybe one knows something useful for fluid trainers. However if you haven't seen one already, your knee needs an orthopaedic specialist or perhaps just a decent physical therapist.

I don't get along with trainers. I only use them just to keep my legs moving when I can't get outside. I seldom pull much resistance on them and stay in the low ratio gears.

Carbonfiberboy 

The weird looking fluid you found in there doesn't sound right to me. It should be clear or nearly so. I've used a fluid resistance unit on my rollers for 25 years. Something went wrong with the original fluid in it - it got too easy, like the viscosity had gone way, way down. I drained out the old stuff and replaced it with silicone oil treadmill lubricant. That was about 15 years ago and the resistance has stayed consistent over the years. That oil is easy to find online.

I get my resistance unit too hot to touch. Resistance on a bike can be expressed as watts. Useful resistance starts at about 100 watts, so you want your resistance unit to feel like it's had at least a 100w bulb in it.

I ride my rollers more than I ride outside, several hours a week. IME nothing really happens fitness-wise until I've been riding for 45'. That's when the good stuff starts. Also the leg pain if you're not used to it, but that's just part of the "good stuff."

Gym123456

I went to an orthopod around Aug 1 and he didn't think surgery was necessary, although I should have asked more questions about getting some kind of timeline for recovery. I don't expect pinpoint accuracy, but someone must have crunched the numbers to get some kind of high/low average based on age, effort during therapy and outside of it. The stationary trainers at the PT place all have a flywheel and one is a Peloton- once I found that I was able to function on a bike with my knee, I bought a MTB and that was great until the weather turned.

I never used my wind trainer- hated it and became very bored but with the videos that are available now, it holds my interest pretty well and I'll keep using a trainer as long as it works properly. I don't want to drop $1500 or more for a Peloton but may look into one of the other smart trainers, to be able to ride in higher gears and work on cardio & strength.

Gym123456

How thick (WQRT viscosity) is the lubricant? I did see it all over when I searched for it.

I expect some burn and being huffy-puffy after/during a ride- that's part of the experience. If I only wanted to see trees, birds, etc, I could drive in the woods.

Carbonfiberboy 

Haven't the slightest idea. It's not real thick, similar to mineral oil. Doesn't matter that much since you don't have a power vs. speed calibration graph for the trainer, (I don't think).

So what was the doctor's diagnosis? My experience with doctors is that an actual diagnosis can be difficult to get since then the doctor actually has to order tests, look into the problem, and come up with a scientific answer. They're rather not do the work - or maybe not stick their neck out that far?

Gym123456

Might be time to go to a shop that sells fluid trainers so I can spin the wheel and compare the resistance/feel.

Carbonfiberboy 

The thing is, you don't really care about the precise thickness. If it's a little thinner, you spin the wheel a little faster in a higher gear. No big deal. For a long time, I ran my rollers with an essentially empty fluid unit. Man, I was fast!

Gym123456

By design, the faster the impeller spins, the harder it is to move in any fluid but the oil that's in there is very thick. I would have assumed it would be thinner since even an automatic transmission's oil doesn't need to be in order for the torque converter to work properly.

Carbonfiberboy 

Quite so. Something went wrong with that oil, who knows what.

PeteHski

Well that's 2 months of potential quality indoor training gone while you ponder over this. I would consider treating yourself to a smart trainer. They are not that expensive these days (especially wheel-on models eg. Kickr Snap) and plenty of used and refurbed ones around. It would be a better experience all round. I do take your point about the waste mentality, but it just seems a bit counter-productive in this case.

FWIW I've had several different indoor trainer setups over the years, everything from those crappy wind trainers you mentioned right through to the latest smart trainers and only the latter have really cut it for me. Everything that came before soon became relegated to a clothes stand. Not saying a fluid trainer isn't a viable option, but I wouldn't spend much money or effort on one that wasn't working properly.

Gym123456

I used it, it just had this issue and I ride every time I go for therapy so it's not my only option.

burnthesheep

I didn't understand how it's wasteful to get a different used unit, not buy another new one. If someone is going to chuck it anyway, how is that waste? Folks post on our local ride group a lot "come get this if you want it, because next destination is the waste bin".

I appreciate the resourcefulness, but don't agree that anything is being saved.

Local bike Facebook group or Craigslist, $30, done. No waste. No more trips around town hunting for parts or fluids or what have you.

PeteHski

Okay, but the word "quality" was perhaps more pertinent