Front Rotors
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Tourer
Joined: Jan 2017
Posts: 378
Likes: 100
From: PA
Front Rotors
I just got back from a long(ish) tour, York Pa to Niagra Falls to meet my brother, then to Americade in Lake George, a visit to Maine, dropped back in New Hampshire to climb Mt. Washington, then a day at Laconia before riding back to Niagra Falls then home.
I live in one of those states that holds you hostage to yearly inspections, I ride to the dealership and they inform me that bike has failed it's yearly inspection due to the front rotors being warped. We had no rain at all on the trip, but I suppose it's possible that they cooked on the way back down from Mt. Washington. The thing is, my rotors are only 15 months old and have about 8k on them. I do plenty of riding in the rain but none of my old bikes ever had a problem with this, I'm hard pressed to believe that I'm on my 3rd set of rotors in 4 years of ownership of my SG.
Is this typical life expectancy for OEM rotors?
Would it be worthwhile to upgrade to floating rotors?
Thanks!
I live in one of those states that holds you hostage to yearly inspections, I ride to the dealership and they inform me that bike has failed it's yearly inspection due to the front rotors being warped. We had no rain at all on the trip, but I suppose it's possible that they cooked on the way back down from Mt. Washington. The thing is, my rotors are only 15 months old and have about 8k on them. I do plenty of riding in the rain but none of my old bikes ever had a problem with this, I'm hard pressed to believe that I'm on my 3rd set of rotors in 4 years of ownership of my SG.
Is this typical life expectancy for OEM rotors?
Would it be worthwhile to upgrade to floating rotors?
Thanks!
HDF Community Team
Joined: Nov 2012
Posts: 6,189
Likes: 2,419
From: USA
Well, you're in a bit of a catch 22, and probably the easiest thing to do is to simply let them replace the rotors.
You can take the bike back and measure it yourself, then try to argue with them about your readings. But it's their reading that legally counts, since they are the inspection station.
You can also take the bike back and use hammer to tap the rotor back flat. It works, I've done it on simple single plate rotors before. Then you take the bike back for a re-testing. Pretty easy to get a rotor flatter, pretty hard to get a rotor to within a tight spec.
You can take the bike back and measure it yourself, then try to argue with them about your readings. But it's their reading that legally counts, since they are the inspection station.
You can also take the bike back and use hammer to tap the rotor back flat. It works, I've done it on simple single plate rotors before. Then you take the bike back for a re-testing. Pretty easy to get a rotor flatter, pretty hard to get a rotor to within a tight spec.
Stellar HDF Member
Joined: Jun 2009
Posts: 3,423
Likes: 421
From: Northern, Ohio (Yuck!)
Let me tell you a secret...
Heat warps rotors.
When you come to stop your disks are very hot because they have been converting your momentum into heat via friction. Now you sit at the stop light with the front brake pistons pushing these incredibly hot disks into your rotor with great force. A large amount of heat is being transferred to 1 spot on the rotor while this happens. So is it any wonder the rotors often warp?
Don't worry though. The fix is easy. Every time you stop do this simple thing. As soon as you come to complete stop let the bike roll forward or backwards about 6" before stopping to wait out the light. The heat bleeds off the disk very fast (it is designed to do that) and those couple of seconds and 6" are all you need to prevent warping.
I warped the front on my RGU at 7000 miles. Fortunately someone told me about this and 50,000 miles later I have never had another one.
Heat warps rotors.
When you come to stop your disks are very hot because they have been converting your momentum into heat via friction. Now you sit at the stop light with the front brake pistons pushing these incredibly hot disks into your rotor with great force. A large amount of heat is being transferred to 1 spot on the rotor while this happens. So is it any wonder the rotors often warp?
Don't worry though. The fix is easy. Every time you stop do this simple thing. As soon as you come to complete stop let the bike roll forward or backwards about 6" before stopping to wait out the light. The heat bleeds off the disk very fast (it is designed to do that) and those couple of seconds and 6" are all you need to prevent warping.
I warped the front on my RGU at 7000 miles. Fortunately someone told me about this and 50,000 miles later I have never had another one.
Road Master
Joined: Nov 2018
Posts: 922
Likes: 898
From: Upstate NY
How exactly did they determine they were warped? Ive never seen a shop take a runout gauge to a rotor during an inspection. Unless they actually rode the bike? How would they know? Better yet, did they FEEL warped to you? I bought my EG used and the front brakes would squeal and pulse at higher speeds and downright grabbed at lower speeds. They (warped rotors) are hard to miss if you are riding, but I cant imagine anyone noticing during a visual inspection.
Road Captain
Joined: Mar 2007
Posts: 612
Likes: 15
From:
Gotta chime in here. Brake rotors often give a grab and slip type feel when they are warped AND heated up. After they cool down sometimes they return to a less warped configuration and feel okay until they warm up again and the metal fatigue overtakes the machined shape. Very noticeable as you coming to a stop and almost stopped and catches on a "high spot" and you stop more abruptly then you were trying to modulate the stop. Hate it actually as I pride myself on being as smooth a rider as possible, that includes stopping.
Thread Starter
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Tourer
Joined: Jan 2017
Posts: 378
Likes: 100
From: PA
How exactly did they determine they were warped? Ive never seen a shop take a runout gauge to a rotor during an inspection. Unless they actually rode the bike? How would they know? Better yet, did they FEEL warped to you? I bought my EG used and the front brakes would squeal and pulse at higher speeds and downright grabbed at lower speeds. They (warped rotors) are hard to miss if you are riding, but I cant imagine anyone noticing during a visual inspection.
I put a set of new OEM rotors, bolts, and brake pads on since I was there. I had to buy them from another shop because the dealer inspecting my bike didn't have any rotors in stock. Probably due to an overzealous inspection process
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HDF Community Team
Joined: Nov 2012
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From: USA
http://www.dot.state.pa.us/Public/DV...ubchapterh.pdf
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Road Warrior
Joined: Feb 2009
Posts: 1,274
Likes: 130
From: Now Western TN
Probably not worth the fight, but in looking at the PA inspection requirements, there is nothing there about runout. Groves in the rotor cannot be deeper than 0.015", linings no thinner than 1/32" and not broken or loose, rotor no thinner than stamped spec on the rotor. Nothing about runout.
http://www.dot.state.pa.us/Public/DV...ubchapterh.pdf
http://www.dot.state.pa.us/Public/DV...ubchapterh.pdf
This must be the dealer doing this to make money.
PPearl, who was it? 1stCapital HD?
Road Warrior
Joined: Feb 2009
Posts: 1,274
Likes: 130
From: Now Western TN
Let me tell you a secret...
Heat warps rotors.
When you come to stop your disks are very hot because they have been converting your momentum into heat via friction. Now you sit at the stop light with the front brake pistons pushing these incredibly hot disks into your rotor with great force. A large amount of heat is being transferred to 1 spot on the rotor while this happens. So is it any wonder the rotors often warp?
Don't worry though. The fix is easy. Every time you stop do this simple thing. As soon as you come to complete stop let the bike roll forward or backwards about 6" before stopping to wait out the light. The heat bleeds off the disk very fast (it is designed to do that) and those couple of seconds and 6" are all you need to prevent warping.
I warped the front on my RGU at 7000 miles. Fortunately someone told me about this and 50,000 miles later I have never had another one.
Heat warps rotors.
When you come to stop your disks are very hot because they have been converting your momentum into heat via friction. Now you sit at the stop light with the front brake pistons pushing these incredibly hot disks into your rotor with great force. A large amount of heat is being transferred to 1 spot on the rotor while this happens. So is it any wonder the rotors often warp?
Don't worry though. The fix is easy. Every time you stop do this simple thing. As soon as you come to complete stop let the bike roll forward or backwards about 6" before stopping to wait out the light. The heat bleeds off the disk very fast (it is designed to do that) and those couple of seconds and 6" are all you need to prevent warping.
I warped the front on my RGU at 7000 miles. Fortunately someone told me about this and 50,000 miles later I have never had another one.
Very good advice right here if you have been riding hard on the brakes. I don't find the need to do this on casual rides unless there are a lot of lights.