Indoor Bike Improvement #9 - Let's Talk About Sweat

9 of 10 - A Sweaty Problem

When I added fans to my indoor bike, I thought my problems with sweat had been blown away.

There was less sweat on the floor mat but it still dripped from my chin directly onto the bike. I didn't give it much thought until I read that many people were seeing rust on their indoor bikes. After observing moisture patterns for a month, I came to realize: Sweat on my Stages SB20 bike could be an issue.

I don't think sweat problems are unique to my brand of bike. Many of the issues and fixes described here will also apply to other brands.

Sweat Patterns

In my case, about 20% of sweat production falls over the handlebars, 50% in the middle of the frame and 30% nearer to the seat post.  

Depending on your physical measurements and riding style, you may see sweat distributed in different proportions.

Where does Moisture Go?

Ideally, sweat should go nowhere. You wipe down your bike after each ride and the problem is solved. 

The reality is: You can miss some spots. Sweat also flows freely during your ride. And oh yeah, you might not always remember to do a wipe down.  

Sweat Infiltration

After about a year of riding, sweat collected under my bike's plastic cover. It was a mixture of salt brine (bad) and small bits of rubber from the belt drive (expected). Interior metal surfaces (steel and aluminium) showed early signs of corrosion.

I also noticed that some sweat falls onto my flywheel through the water bottle cages when I am standing or on the drops. It is sprayed in all directions, including inside the plastic cover and onto the metal feet.

Solutions

I ended up trying several solutions that you might find useful depending on your situation and DIY aspirations.

1. Drip Guard

Indoor bike sweat guards are a good option.  To avoid covering the bar tops, I attached them to the water bottle holders. 

I noted a couple of issues:

a) No protection on the forward side of the handlebars over the flywheel.

b) This sweat guard was not long enough or wide enough to protect the top of the plastic cover - particularly near the seat post.

While this solution will be suitable for many riders, I wanted to see if I could further improve moisture resistance.

2. Breathable Handlebar Tape

The Stages SB20 bike ships with water resistant handlebar tape. This adds some moisture resistance. 

FWIW: I think this type of thin and rigid tape was chosen by Stages to help their under-tape "blip buttons" work better.

I switched to traditional cork/foam tape. After using it for a couple of years, I'm confident this type of breathable tape traps less moisture and resists corrosion better than the OEM tape.

3. Moisture Redirection

Sweat that finds its way to the sides of the plastic cover can flow into the holes around the cranks and inside the opening behind the flywheel.
  
I used closed-cell weather stripping to redirect moisture away from the cranks and flywheel.

The results have been surprisingly effective. Sweat now only collects as small drops on the floor pad under the bike.

4. Caulking (and duct tape!)

The upper edges of the plastic covers allow sweat to get inside. This is especially true in my case where the majority of sweat from my chin drips between the handlebars and seat tube.

A few months ago, I applied window caulking to the upper seams on the plastic cover. I also added a small piece of black duct tape along the seam where the plastic shells come together. It worked! Moisture infiltration has stopped.

Issue: Caulking needs to be cleaned off and re-applied each time I remove the plastic cover. Not a big deal, but I did find something better. I describe that fix further down the page.   

5. Moving the Water Bottle Holders

None of the solutions provided so far stop sweat from dripping directly onto the flywheel.  Here are changes I made to better deflect moisture.

a) Moved the water bottle cages rearward eliminate the bike leg gaps. With the addition of a small bead of caulking, sweat is now directed down the outside of bike legs.

b) Added rubber sheets to the cover holes and cut-outs in the bottle cages. This prevents sweat from going through the bottle holders.  

c) Moisture is now prevented from directly dripping onto the flywheel

6. More Weatherstripping

As mentioned earlier, I wanted to improve on the caulking solution (#4 above).  

I applied weatherstripping along the inside of each of the plastic covers. 

The result is removable covers with excellent moisture resistance.

It looks good too.

Final Comments

I think improving sweat resistance is critical. I got lucky when I ignored the issue for a couple of years.  Rust and corrosion had started. I have certainly slowed it down after making these changes. 

I now wipe down my bike after each ride since sweat still drips down the sides and under the bike. None gets inside the plastic cover or onto the flywheel ⛔️. 

Parts List

• Closed cell weatherstripping 
• Breathable handlebar tape
• Bike sweat guard
• Rubber sheets (for water bottle cages)
• Caulking
• Duct tape