Preventing BB Corrosion from Sweating on Trainer?

Hey all, I have a Trek Domane setup on my Wahoo Kickr for TR workouts, and I am on my third BB90 in five months (keeps corroding from sweat). Nothing is worse than feeling that side-to-side play and bearings grinding mid-interval…

I have the tools to replace the BB90 – it’s a terrible bracket standard that leaves the bearings way too exposed, but it’s all I got until I can afford my next bike (happy to take suggestions for a good trainer frame).

I routinely wash my bike and I generously use Park Tool HPG-1 on my BB bearings and spindle. However, my sweat must be radioactive because I notice the corrosion within a few weeks of BB installation.

Other than keeping the BB clean, well-greased, and ensuring torque on the left-crank (12-14nm), I am open to suggestions for preserving the BB90. How do you guys and gals keep sweat away from the BB without affecting crank rotation, if at all possible?

Thanks a ton, and FIVE STARS always to the TR team and this awesome forum!

What is your fan situation? If you are sweating and dripping enough to kill BB’s, I’d guess you could benefit from .ore and better fans. 2 or 3 of the Lasko Performance fans and even cold air can make a huge difference.

Do you have anything like the sweat catchers in use? They can sometimes catch dripping sweat.

Essentially, eliminate sweat as much as possible first, then control any of it that remains to keep it from reaching the BB.

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Most likely this is the source of your corrosion.

It’s really hard to see how you could sweat enough to destroy bottom brackets. How does it even drip in to there? And if you are sweating that much then you need another fan.

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I have one pretty strong ground fan, but I see how optimizing the fan situation would be a good preventive measure.

Temperature probably gets to around 85 degrees in the room I use for training. I’ve heard the team mention Lasko fans several times on the podcast. I’ll try a couple out and possibly a sweat guard, if necessary.

Thanks a bunch, Chad!

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For reference, I am a heavy sweater outside when the heat is up. I train at 70*F or less in my cave, have 3 fans with 2 of those ported to pull cold air from outside anytime it’s cooler outside. All that leads to me rarely having a single drop of sweat hit the floor in even hard workouts.

At 85*F I would melt and be pouring on the bike. If that is the case for you , I think more cooling could reduce sweat and maybe help power too. :stuck_out_tongue:

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I don’t know how you do it in an 85F degree room. My trainer room is about 50-55F now and I still start to feel warm without a fan going.


I wrap a wash cloth around my seat post and junction of the seat stay, seat tube, and top tubes. I secure it on the rear with three clothes pins. I drape a second wash cloth over the top tube and tuck it under the edge of the first cloth. Everything is tight and does not touch my legs. It catches all of the sweat and stops it from going into seat tube and further down to bottom bracket. I remove these and wash or air dry outside after each ride. This has worked very well for me and protected my bike for the long term.

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Good to know. I’ll definitely try your suggestions out!

That’s a GREAT idea to port the fans against the window – thanks again, Chad.

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Shawn, thanks for the advice. Glad it’s worked well for you – I’ll give the washcloths a try.

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