Thread: How hot do the cassette and chain get?

1. How hot do the cassette and chain get?

Just curious, how hot would a cassette and chain get from the friction of normal riding? Obviously there are many variables like lubrication type, cleanliness of lube, what gear ratio is being used, and so on, but does anyone have a general idea of what temps the drivetrain might reach?

Thanks.

2. If you could measure a temperature difference from friction I'd be amazed, there'd be more temperature gain from sitting in the sun, there's not much friction in anything other than the chain plates. Bikes are quite efficient in the drivetrain.

The brake discs on the other hand can get warm enough to raise a blister and melt some grease in the left side bearings.

3. A good chain transmission can be 95 to 99 % efficient.

Bikes are good chain transmissions.

A rider might put out 200 watts steadily.

So friction woould account for about 2 to 10 watts.

This amount of heat is released by small semiconductors, with a 5 to 10 C rise.

As above the chain as enough surface area to release this heat at a very small temperature rise <<1C.

4. Thanks fellas. That all makes sense.

5. Friction?

Not much friction going on. The cogs and chainrings are spaced enough that the sides of the chain don't rub. If it does it's cause your drivetrain isn't tuned properly.

As far as the interior of the chain goes, the teeth of the cogs and chainrings grab the chain and push forward. Again no friction, just the initial contact when the teeth grab the chain and start pushing.

I doubt there is any significant temperature gain. Just being out in the sun is all the heat your going to get. In the winter your tongue will probably stick to the chain its that cold. Throw some lube on the tongue to unstick yourself and tell me how it tastes

6. Originally Posted by Gondo
As far as the interior of the chain goes, the teeth of the cogs and chainrings grab the chain and push forward. Again no friction, just the initial contact when the teeth grab the chain and start pushing.
Any high school physics teacher would tell you that there is a fair bit of friction going on in this scenario, it's just not what you normally think of friction as (two hands rubbing together).

7. I was just trying to figure out if the thermal stability of silicone lubricants would be an advantage in bike lubes. I am a silicone chemist who likes to ride. I am thinking of making my own silicone based lube for my bike, just for fun.

8. Heat is not an issue with bicycle drivetrains.

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