Rear axle running temperature

[GM6VXB]

Got a new toy, infra red thermometer. Really for other jobs
where a normal thermometer is not suitable.

Just done a 20 mile run before tomorrows rain and on
return home checked the rear axle temperature.
Axle was 29C with ambient temperature of 9C (hot for NE Scotland !).
Temperature taken just next to diff filler plug.

Wonder if this seems about right and if anyone else has checked theirs.
I suspect about right, but always worth checking against others.

Martin, GM6VXB

[Chris KC]

Congratulations Martin, you seem to have found a new thing to worry about!

I know it's a lot easier to drain axle oil after a run, so it must run warmish. If it were too hot to touch I'd raise an eyebrow.

[Steve Jones]

I've had an infra red thermometer for some years. It's useful to confirm that my beer is at the best temperature

Steve

[Reckless Rat]

Ignorance is bliss!

[Duncan Grimmond]

I got one of they infernal red thermometisers and used it to help me to worry about the temperature differential between the cylinders of my Vee-twin BSA trike...

[Colin Morgan]

I agree with the general sentiment - we perhaps don't want to know.

However, a quick back of the envelope calculation shows the following.  Assuming the axle is in equilibrium at 29 C in an ambient temperature of 9 degrees, and has an area of 0.65m2, about the same as a 9" sphere, and it is cooled by the air flowing past plus thermal radiation, then it would be losing about 400 watts by forced convection and about 70 watts from radiation - so about 500 watts overall.  For an average engine power of 8 bhp or 6 KW this suggests a loss of about 8% - which isn't unreasonable for an axle/differential?

[GM6VXB]

Thanks Colin.
I forgot about convection cooling so happy the axle is running at about the right temperature.
While trying to see if adjusting the two thrusts would quieten down a noisy axle, I got the lot up
to 39C, no cooling so explains why it went so high.

Axle BTW even though a new crown and pinion is (to me) noisy even though I have done all the
adjustments three times and replaced the crown bearings which were in good condition anyway.

I suppose just keep driving and wait to see if there is a big bang !.

Martin.

[Graham Barker]

Ah. The Big Bang Theory - run it 'til it busts.

[Dave Mann]

I find my hand is a good temperature sensor, if it's so hot it hurts something is wrong.