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[TNCreator]

Just for fun and curiosity, I checked the bike with IR after a chill ride, not much speed but a few dynamic starts at the green light.

the only surprising thing here is how the front tire is hotter than the rear despite the fact that it does not do much in this kind of riding.

the air temp was 20°c (68°F)


motor (90°F)


battery (73°F)


rear caliper (100°F)


rear tire (85°F)


front tire (91°F)

[Grauteufel]

Narrower contact patch? Softer compound? The fronts have to experience more loads, I know on the missus’ bmw it goes through front twice as fast as rears.

[Specter]

That's a heavy fucking battery pack you got on those bikes.   You stop and it will load the shit out of the front tire, which is smaller, thinner.

On my racing bike i have to run it about 5 pounds higher to handle that massive load it is going to get when i come into a turn and want to go from 110 to about 60 in a few seconds.   The front tires get a lot of a workout and they are smaller,  so yes they will tend to get hotter under circumstances.  It's nothing to worry about really unless the thing is baking hot,  then you may have it way under inflated.

Aaron

[jotjotde]

That are interesting data! Thanks for that!

I often thought about why the front tyre is usually smaller than the back tire. As Aaron pointed out, the front is stressed more heavily when braking, so that is not the issue.
Is the higher temperature the wanted effect (better grip)?

[T.S. Zarathustra]

Most likely the higher front temperature is due to the front tire being narrower. With the same weight/load a narrower tire will heat up faster due to less surface area for cooling.

Shame you didn't get a photo of the break disks.

[Pard]

That are interesting data! Thanks for that!

I often thought about why the front tyre is usually smaller than the back tire. As Aaron pointed out, the front is stressed more heavily when braking, so that is not the issue.
Is the higher temperature the wanted effect (better grip)?

[Pard]

Very cool pics and data!

Put on a set of tire pressure monitors. 

https://my-fobo.com/product-family/FOBO_Bike_2

You are looking for about 20% Psi increase rear cold to hot, and 10% Psi for the front.

The rear wheel should be getting hotter than the front if inflated properly.  The pressure settings will need to vary based on tire used, surface upon which you are riding, temp of the surface, and style of riding.  In very cold temps, the tire pressure will barely increase even when riding quickly.

I run 35 Psi rear for Q5s tires, and 42 Psi front set cold, to get that 20% increase rear /10%  increase front when hot. 

The rear tire is always hotter.  Cooling airflow to the front tire helps keep it cooler as well, while the rear gets less of that.

[jotjotde]

Nice video. Thx for posting that, again I learned something 

Isn't using higher pressure for the front than the rear contrary to what you usually see?
My driving instructor recommended 2.5/2.7 bar front/rear (36/39 psi) and I found that feels way better than the factory recommendation (2.9 bar/42 psi front and rear).

[Pard]

Nice video. Thx for posting that, again I learned something 

Isn't using higher pressure for the front than the rear contrary to what you usually see?
My driving instructor recommended 2.5/2.7 bar front/rear (36/39 psi) and I found that feels way better than the factory recommendation (2.9 bar/42 psi front and rear).

Yes, many bikes have a factory recommended rear tire pressure higher than the front.  A Ninja 400/500 is 28 front and 32 rear Psi. 

Depends on the bike, the tire, and the mission.

Can't go wrong with factory recommended pressures, but deviation from that recommendation is fine so long as you have some way to monitor the results before you go too far out of specs.