LGT Front Rotor Difference - 2005 vs 2006+

I went to get rotors for my 2005, figured I would go with OEM this time. I found it interesting that 2005's had a different part number then 2006. Since my 2012 needed rotors too I got both sets and got a chance to compare them.

 

2005 Part Number: 26300AG001 (Made in Japan)

2006+ Part Number: 26300AG02A (Made in USA)

 

2005 Rotor (26300AG001) vs 2006+ Rotor (26300AG02A)

Both are brand new, 26300AG001 came in a sealed bag, while 26300AG02A was just in the box, hence the rust on it.

http://legacygt.com/forums/attachment.php?attachmentid=262350&d=1519532794

http://legacygt.com/forums/attachment.php?attachmentid=262352&d=1519532794

http://legacygt.com/forums/attachment.php?attachmentid=262351&d=1519532794

 

Side comparison: Notice that the holes seem bigger on the 2005 rotor

http://legacygt.com/forums/attachment.php?attachmentid=262369&stc=1&d=1519533690

 

For comparison sake, here is a Centric rotor side:

http://legacygt.com/forums/attachment.php?attachmentid=262368&d=1519533258

 

 

Front:

2005 has fully machined surface

http://legacygt.com/forums/attachment.php?attachmentid=262353&d=1519532794

 

2006+ is finished differently and not to the edges

http://legacygt.com/forums/attachment.php?attachmentid=262361&d=1519533258

 

 

Back:

2005 once again is fully surfaced

http://legacygt.com/forums/attachment.php?attachmentid=262354&d=1519532794

 

2006+ rear is surfaced to the outside edge but the center is not

http://legacygt.com/forums/attachment.php?attachmentid=262362&d=1519533258

 

 

Weight

2005: 21.4lbs (don't mind the paint chop, digital camera hates LCD display)

http://legacygt.com/forums/attachment.php?attachmentid=262356&d=1519532794

 

2006+: 22.8lbs

http://legacygt.com/forums/attachment.php?attachmentid=262365&d=1519533258

 

For comparison sake here is a 37k mile Centric

http://legacygt.com/forums/attachment.php?attachmentid=262367&d=1519533258

 

You saw that right, 2005 rotors are 1.4 pounds lighter then 2006 ones! But why...

 

Total Thickness: Same for both so that's not it

2005: 29.7mm

http://legacygt.com/forums/attachment.php?attachmentid=262355&d=1519532794

 

2006+: 29.7mm

http://legacygt.com/forums/attachment.php?attachmentid=262363&d=1519533258

 

Thickness of each side

2005: Front 8.3mm, Rear 8.5mm

http://legacygt.com/forums/attachment.php?attachmentid=262360&d=1519533258

 

2006+: Front 9.6mm, Rear 9.8mm

http://legacygt.com/forums/attachment.php?attachmentid=262364&d=1519533258

 

Another interesting bit, 2006+ has balancing cuts, both of the 2005 rotors didn't

http://legacygt.com/forums/attachment.php?attachmentid=262366&d=1519533258

 

Overall I think the 2005 rotors are nicer quality (and not rusty!). Plus they are much lighter, not only do they save you 2.8lbs in unsprung weight , they save you that much in rotational mass. I think these might be a great upgrade for those looking to shave every last bit of unsprung weight. Aluminum control arms cost much more and save you less in unsprung weight.

A lot of heat gets dumped into the rotors quickly when you brake hard. When not braking the heat radiates out. Extra weight is extra heat capacity / storage. Heavier / thicker rotors are less likely to overheat the brakes if they are being pushed to their limits. Nice to have the light or heavy rotor option to chose for what you're doing with the car. You can always start with the light rotors and switch to the heavier ones if you're getting into brake fade (likely from heavy track use.)

For daily driving a lower mass one would be better because it will heat up faster, thus warming up brakes faster (especially brakes that need heat in them to work). But at the same time it will dissipate the heat quickly too, which might put it back into the cold zone.

 

Also for track duty, while heavier mass one will stay cooler longer, once it heats up it won't be able to loose heat nearly as quickly either, thus staying much hotter for longer time.

 

This is actually similar to air to air intercoolers their core's mass debate. On one side a dense core will stay cooler longer, but once it heats up it's gonna take it a long longer to cool back down too, especially when it comes to a heat soaked TMIC.

I agree. The LGT brakes are large for a vehicle this size / hp. For 99.9% of applications the lighter rotor is probably the better choice.

 

If brake fade / failure from the rotor being too thin was a safety issue, Subaru very likely would have upreved the 2005's to the thicker rotors as well.

Also note Subaru decided to add weight to the rotor for the newer models. Manufacturers want to remove weight where they can, they didnt add weight to the rotor for no good reason. May have been to use OE parts in some race class, who knows..

 

For the other small window of people tracking their cars with more and more hp, they will eventually run into the upper limit of the brakes. Even with race pads, fluid, etc. The heavier rotors will help here. Good explanation here on thermal mass / heat capacity, http://www.racingbrake.com/v/main/rotor_is_important.asp

Interesting. I am looking to get front brakes refresh, and would prefer OEM rotors. Looks loke 2005 is the way to go.

 

Thanks for sharing.

I agree. The LGT brakes are large for a vehicle this size / hp. For 99.9% of applications the lighter rotor is probably the better choice.

 

If brake fade / failure from the rotor being too thin was a safety issue, Subaru very likely would have upreved the 2005's to the thicker rotors as well.

Also note Subaru decided to add weight to the rotor for the newer models. Manufacturers want to remove weight where they can, they didnt add weight to the rotor for no good reason. May have been to use OE parts in some race class, who knows..

 

For the other small window of people tracking their cars with more and more hp, they will eventually run into the upper limit of the brakes. Even with race pads, fluid, etc. The heavier rotors will help here. Good explanation here on thermal mass / heat capacity, http://www.racingbrake.com/v/main/rotor_is_important.asp

 

They did change country of origin. Which means they changed who manufactures their rotors. Perhaps the old rotors had better metal structure, thus didn't need as much mass to be as good. New US made ones might have inferior iron thus they need to beef them up to prevent them from cracking/overheating.

 

Neverless, that was a good read!

Also to note something I just dealt with 3 weeks ago, is my car is an "06" built in 11/05. Come to find out when I had to replace the calipers, brackets and hardware I had to order 05's. The 2000-04& 2006-12 used a smaller components. The 05 model uses the above larger/ thicker rotors and also calipers and ect.

 

The difference that I noticed was 20mm on mounting locations, and the rotor "slot" on the caliper and bracket was 15mm's wider.

You probably got non turbo ones for 05-09. My 2012 2.5i (non turbo 4 cylinder) with 17" wheels, uses the same size as our GT's, which is the same as GT and 3.6r's in 2012.

Thanks for the interesting comparison!

They did change country of origin. Which means they changed who manufactures their rotors.

 

 

This. Plain and simple. It meets the specs given.