Taming a Noisy Tacx Genius Trainer

This winter I noticed my Tacx Genius growing louder and louder until it eventually became such a nuisance that I contacted Tacx support.  As it turns out, Tacx trainers have a tendency to become very loud over time.  The trainer’s colic protest is due to the fact that the small roller is not a piece of solid metal, but rather a thin sleeve that is wrapped around a urethane core.  12 holes in the sleeve keep the metal sleeve connected to the core – much like the old dot-matrix printers that used paper with a tractor-feed along the sides.  Over time, this “tractor-feed” begins to wear when the temperatures of the metal cause expansion and the urethane heats up causing the tractor-feed to lose it’s grip on the metal sleeve.

This has been a known issue for more than 8 years when Tacx began making turbo trainers with the tractor-fed metal sleeve design.  To diagnose my trainer, I learned that a relatively quiet Tacx trainer can produce upwards of 88db @ 55kph if inflicted with the disease. After downloading a sound level app on my phone, my fears were confirmed as my Tacx Genius had it bad: 100db max, 92db average, and soft-pedaling uphill still produced a horrific minimal noise level of 86db.  Very bad indeed.

Why Tacx continues to employ this system is outside the scope of this article. I contacted Tacx and they immediately understood the problem and said the issue would be covered under warranty.  Great!  Just a quick visit to my nearest Tacx dealer would steer me onto quieter virtual roads!  When the dealer contacted Tacx to process the warranty, however, they said the warranty had expired for my 2.5 year-old Tacx Genius but the replacement part is available for the bargain price of ~$400 (+ international shipping, duties, tax, and a month-long wait). Thanks to the Tacx user forum, a DIY option surfaced that might be a quick and cost-effective fix.

The original solution was posted back in 2008, many years before the Genius was released, and it worked well for the Tacx Fortius in which the tractor-feed plugs wear down to almost nothing – allowing the metal sleeve to freely rotate around the core.  A user from Leeds in the UK using the screen name of “Techno” is often credited for dreaming up the (now famous) remedy known as “The Epoxy Fix“.  The repair involves drilling through the tractor-feed holes and refilling the plugs with a fresh infusion of epoxy.  On the Genius, it’s not obvious that the tractor-feed is worn out.  The sleeve does not rotate or rattle but it does appear that the sleeve or the urethane has been disfigured such that the sleeve shifts on the core as the tire rolls along.  With the Genius, it almost feels that the urethane core has shrunk and the pocket of air between the metal and the plastic causes 1mm of movement.  If you press your finger hard on the Genius roller, you can hear a faint “clunk” as the metal repositions itself.  At 100+ revolutions per second, this innocent pin-drop noise explodes into a 100db Symphony of Destruction.

It’s a little daunting to drill through the heart of a very pricy indoor trainer, but once Tacx deemed my Genius a bastard child, I knew it was time to get dirty and venture into the dark alley of DIY.   It is unclear if the Epoxy Fix is the medicine my Genius needs, but it certainly can’t hurt as 100db will ultimately lead to bigger problems, likely in the direct form of hearing loss not to mention indirect pain caused by aggravated family members or neighbors.  While the forum thread covers all aspects of the repair, it does lack step-by-step photos which would have been helpful, especially to gauge the difficulty of the repair, so I’ll document the steps I took.  I’m sure it will be of value to someone.

---

Step 1: Gather your materials.
– Grab Tacx’s flagship model, the Genius. The louder the better:

Tacx Genius

The focus here is on repairing the thin metal roller with small “tractor-feed” holes that allow it to grip the polyurethane core:

This is the “tractor-feed” or “polyurethane plugs” that help the sleeve grip the plastic core. On this Genius, the tractor-feed doesn’t look too bad, but there are some signs of wear:

Noisy Tacx, check.  Tractor-feed wear or “click” when pressed with your thumb, check.  Now you’ll need to locate some epoxy.  The key here is to find one that works well with polyurethane, has at least a 15 minute work time, and will withstand some heat.  Most of the epoxies I found at the hardware stores I visited were 1 minute and 5 minute versions.  It took a few different stores, but eventually I found a 20 minute work time epoxy.

You will also need:
– A drill with 4mm bit (or 5/32″ bit)
– Some tape for keeping debris from getting inside the motor and resistance unit
– A toothpick
– A needle
– Safety measures to protect yourself from the epoxy which is nasty stuff (gloves, eye-protection, mask, and a well ventilated room that you can quarantine off for a day – the smell is something you’ll want to be able to escape from so a basement, garage, or workshop is recommended… try NOT to do this in your family’s kitchen or living area)

Step 2: Tape off all areas of the trainer with the exception of 4 holes (you can only work on 4 holes at a time, so you will need to break the process up into 3 parts to get to all 12 holes).  The tape will help stabilize the roller and keep the epoxy from getting inside the trainer.

Step 3: Drill out the 4 holes with the 4mm (or 5/32″) bit.  The plastic is soft and drills through easily.  Continue until you feel resistance as the bit will eventually hit the metal axel.

---

Step 4:  Apply the Epoxy
When adding the epoxy to the holes, I used a toothpick and a pin to apply.  You can be as messy as you want and use the taped areas to scrape off access epoxy or to scrape more into the holes as needed.  Use the needle and swirl the epoxy into the hole to ensure air is not trapped inside.

---

Step 5: Level off the epoxy, leaving it a fraction of a millimeter higher than the metal roller.  It doesn’t have to be exact at this point.

---

Step 6: Wait 20-30 minutes.
Step 7: Remove the tape from the metal roller.  The epoxy will be rather ugly and there might be some on parts of the metal sleeve which is fine.  You can easily remove the epoxy with a rotary tool with a wire brush bit.  In subsequent rounds, I learned it was best to keep the tape on the trainer’s black plastic body for this step to prevent debris from getting inside the trainer.  You will definitely need to wear a mask for this step.  This stuff oozes with nasty chemicals – such that one would almost expect to get cancer with longterm exposure.

---

Step 8: Finished! (This set).  Remove all tape.

---

Step 9: Turn the roller and expose a new set of 4  holes and repeat the process (return to Step 2-8) until all 12 holes are complete.

---

Step 10: Wait at least 24 hours before riding. Enjoy the pain and misery of riding indoors with newfound appreciation and splendor.