986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Reason for one rotor being hotter then other?

Lil bastard · 03-23-2011, 01:27 AM

I don't see a problem. A mere 15 degrees (especially in the 100 degree range) isn't a big deal and doesn't point to anything in particular.

If you had a caliper or pad sticking, it would certainly be a bigger difference than you're seeing. One bearing may run a little hotter than the other due to different amounts of grease, different loads, etc.

I chalk it up to errors in methodology.

I assume you used a Pyrometer to check temps, likely an IR Pyrometer at that.

Well, you probably checked one side, then the other. If you checked the left 1st, then the right had additional time to cool.

Also, there is an innaccuracy in every instrument. Add to this that the Pyrometer can be fooled. If you had a light source on one side such as a floodlamp, halogen or even the sun, you're likely to get slightly different readings.

You're trying to pinpoint a variable speed vibration. These are almost always due to a tire/wheel imbalance. Have you roadforce balanced the tires/wheels? When?

If so, have you weighed them? How old (miles) are your tires? Are all 4 tires the same 'age'? When was your last alignment? 4-wheel alignment?

Alignments are not mileage dependent. Get an alignment, hit a pothole 1 mile away coming from the alignment store, and you need another alignment, or you'll have a vibration due to the differences one side to the other because of the pothole.

I don't think your issue stems from differences in temps one side to the other.

Cheers!

03-23-2011, 01:27 AM	#2
Lil bastard Registered User Join Date: Feb 2008 Location: Du Monde Posts: 2,199	I don't see a problem. A mere 15 degrees (especially in the 100 degree range) isn't a big deal and doesn't point to anything in particular. If you had a caliper or pad sticking, it would certainly be a bigger difference than you're seeing. One bearing may run a little hotter than the other due to different amounts of grease, different loads, etc. I chalk it up to errors in methodology. I assume you used a Pyrometer to check temps, likely an IR Pyrometer at that. Well, you probably checked one side, then the other. If you checked the left 1st, then the right had additional time to cool. Also, there is an innaccuracy in every instrument. Add to this that the Pyrometer can be fooled. If you had a light source on one side such as a floodlamp, halogen or even the sun, you're likely to get slightly different readings. You're trying to pinpoint a variable speed vibration. These are almost always due to a tire/wheel imbalance. Have you roadforce balanced the tires/wheels? When? If so, have you weighed them? How old (miles) are your tires? Are all 4 tires the same 'age'? When was your last alignment? 4-wheel alignment? Alignments are not mileage dependent. Get an alignment, hit a pothole 1 mile away coming from the alignment store, and you need another alignment, or you'll have a vibration due to the differences one side to the other because of the pothole. I don't think your issue stems from differences in temps one side to the other. Cheers! __________________ 1990 Porsche 964 Carrera 4 Cabriolet 1976 BMW 2002 1990 BMW 325is 1999 Porsche Boxster (gone, but not forgotten) http://i933.photobucket.com/albums/a...smiley-003.gif Never drive faster than your Guardian Angel can fly!