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Discussion Starter #1
If I change pad compounds, do I have to get new rotors? SRAM suggests that but I fail to see why.
 

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No. It’s hard to kill rotors.

I use these pads, as good or better as OEM and far cheaper.

Truckerco are great. Only pads I use. Far better than Shimano pads and waaayyy cheaper.

You can get them on ebay and Amazon, both with free shipping. I don't know if they charge shipping if you order from their website.
 

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Russian Troll Farmer
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Well, if you go for metallic pads, a lot of the cheaper rotors say "organic pads only", so maybe that's what they are talking about. Metallic pads will chew up a soft steel rotor pretty quickly.
 

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'brifter' is f'ing stupid
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They advise new rotors just like car shops will when replacing pads. Disc brakes work by depositing a tiny bit of pad material on the rotor when bedding in the pads. If you change pad compound you should at least clean/sand the rotor to remove as much pad material as possible. I've never really had any issues doing this.
 

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They advise new rotors just like car shops will when replacing pads. Disc brakes work by depositing a tiny bit of pad material on the rotor when bedding in the pads.
That's not why they advise replacing car rotors. Rotors are normally turned/resurfaced with a few mils removed from each braking surface because the rotors have uneven wear and those small ridges decrease stopping power and shorten pad life. When rotors get too thin they're more susceptible to overheating and the caliper pistons can over-extend. Sadly, some cars nowadays don't design their rotors to be resurfaced. And if we're talking about ceramic pads, then I have no idea....
 

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They advise new rotors just like car shops will when replacing pads.
Huh? Usually car rotors are resurfaced at least once and are only replaced every 2nd pad replacement - at least on my cars. The exception is if the rotors are badly scored.
 

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Russian Troll Farmer
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Huh? Usually car rotors are resurfaced at least once and are only replaced every 2nd pad replacement - at least on my cars. The exception is if the rotors are badly scored.
On REALLY expensive cars with 'carbon brakes', the pads and rotors are both replaced at the same time. I've worked on cars for better than 45 years, and every time I've resurfaced my rotors, they end up either warping or going undersize before the replacement pads are at 50%. So, for the last 5 years or so (at least since being able to find decent, low priced parts online), I've replaced my rotors every time I've replaced the pads. It's quicker, works better, lasts longer, and only costs a bit more.
 

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On REALLY expensive cars with 'carbon brakes', the pads and rotors are both replaced at the same time. I've worked on cars for better than 45 years, and every time I've resurfaced my rotors, they end up either warping or going undersize before the replacement pads are at 50%. So, for the last 5 years or so (at least since being able to find decent, low priced parts online), I've replaced my rotors every time I've replaced the pads. It's quicker, works better, lasts longer, and only costs a bit more.
I guess there is one more reason I don't own REALLY expensive cars. My last car needed new pads at 50K miles and new rotors at 100K miles. It probably helps that I drive a manual, so I downshift a lot to slow the car.
 

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Come to think of it, I know the last two brake jobs I did, I did not get the rotors turned. 2010 Accord and 2007 F150 4x4, had not issues
 

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Come to think of it, I know the last two brake jobs I did, I did not get the rotors turned. 2010 Accord and 2007 F150 4x4, had not issues
I don't put a lot of miles on cars, but my general experience would suggest that you will need new rotors when you need the second set of pads. Sometimes you need rotors with the first set of pads and sometimes you don't. This is with Subarus and Hondas.

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I don't put a lot of miles on cars, but my general experience would suggest that you will need new rotors when you need the second set of pads. Sometimes you need rotors with the first set of pads and sometimes you don't. This is with Subarus and Hondas.
Yep. The rotors are usually resurfaced with the first pad change unless they are scored badly. By the second pad change, there usually isn't enough rotor material left for a resurface.
 

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I guess there is one more reason I don't own REALLY expensive cars. My last car needed new pads at 50K miles and new rotors at 100K miles. It probably helps that I drive a manual, so I downshift a lot to slow the car.
How many miles before you needed a new clutch? Pads and rotors are a lot cheaper to replace than clutches. I have nearly 200K mi on mine and attribute this to NOT using it for braking.
 

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How many miles before you needed a new clutch? Pads and rotors are a lot cheaper to replace than clutches. I have nearly 200K mi on mine and attribute this to NOT using it for braking.
Last car I bought new and traded in at 120K miles with the original clutch still in it.

Downshifting will not make your clutch wear out faster unless you ride the clutch. The vast majority of clutch wear happens when starting from a stop and from poor clutch habits. Having to start up on hills a lot doesn't help either.
 

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Last car I bought new and traded in at 120K miles with the original clutch still in it.

Downshifting will not make your clutch wear out faster unless you ride the clutch. The vast majority of clutch wear happens when starting from a stop and from poor clutch habits. Having to start up on hills a lot doesn't help either.
Unless you rev-match, downshifting will absolutely put wear on the clutch. Of course the degree of wear varies with how it's done.

Slow down with brakes, not engine.
 

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Unless you rev-match, downshifting will absolutely put wear on the clutch.
And the transmission.

Downshifting to get maybe 10% extra life from your brakes (wear items) at the expense of transmission (and clutch) wear doesn't make a lot of sense.

Energy isn't created or destroyed. Only transformed from one form to another.
Engine / transmission braking must convert all the forward energy of your vehicle to friction and heat... within the engine / transmission. That's wear.

Brakes do the same thing. But dissipate the heat to the air. And they are relatively cheap and easy to replace.
 

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And the transmission.

Downshifting to get maybe 10% extra life from your brakes (wear items) at the expense of transmission (and clutch) wear doesn't make a lot of sense.

Energy isn't created or destroyed. Only transformed from one form to another.
Engine / transmission braking must convert all the forward energy of your vehicle to friction and heat... within the engine / transmission. That's wear.

Brakes do the same thing. But dissipate the heat to the air. And they are relatively cheap and easy to replace.
Maybe in theory. All I know is that I have been driving manual transmission cars for decades and the death of my cars has never been the transmission or clutch. The only clutch I have ever had to replace was on a car I bought used - release bearing was shot, but surfaces were still good. Transmissions and clutches are designed to take this. Granted I don't do crazy shiat like downshift into really high rpms. I knew a guy who used to do that and he literally ripped one of the synchros off a gear. That's just stupid.
 

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Your car will slow down when you let off the gas, no need for downshifting. Brakes will last almost 2x as long.
You see a traffic light or stop sign, let off the gas .5 blocks away if 30mph, .5miles if 70 mph.
Take your time, you will get there. Don't be like those "people" trying to run you over.
 
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