ABS - Watch Your Modifications
Road Master
Joined: Sep 2007
Posts: 1,019
Likes: 7
From: Chester County, PA
RE: ABS - Watch Your Modifications
ORIGINAL: Trock
Yes it says that in the book. It also says Never use after market parts on your Harley. Page 5 says don't operate with the forks locked. I didn't expect HD to say yes it ok to change wheel size. The sensor is in the bearings, after lots of checking I'm going to keep mine 21/18's
Yes it says that in the book. It also says Never use after market parts on your Harley. Page 5 says don't operate with the forks locked. I didn't expect HD to say yes it ok to change wheel size. The sensor is in the bearings, after lots of checking I'm going to keep mine 21/18's
Also, it factors original (as designed) contact patch and tire compound (within a threshold).
You could be looking at two scenarios:
1) the ABS kicks in way too late, after the tire(s) have slid enough to get you into some trouble.
2) the ABS kicks in way too early bleed off some braking energy and ending up with less braking efficiency over all.
You do *not* know more than the OEM engineers.
Outstanding HDF Member
Joined: Apr 2005
Posts: 2,106
Likes: 12
From: SoCal
RE: ABS - Watch Your Modifications
There's gotta be some room for leeway here, I mean the tires are going to wear down thereby changing size right? I changed the tires and rims on my truck, and have not thrown any ABS codes, or affected it's application.
Outstanding HDF Member
Joined: Jul 2007
Posts: 2,847
Likes: 0
From: Missouri
RE: ABS - Watch Your Modifications
ORIGINAL: chornbe
As long as the outer-most diameter matches what was OEM, the ABS should still attempt to work as designed. So if your 21 uses a smaller profile tire, thereby matching the original tire's outer diameter, you're good. If not, well, I wouldn't go counting on it.
Also, it factors original (as designed) contact patch and tire compound (within a threshold).
You could be looking at two scenarios:
1) the ABS kicks in way too late, after the tire(s) have slid enough to get you into some trouble.
2) the ABS kicks in way too early bleed off some braking energy and ending up with less braking efficiency over all.
You do *not* know more than the OEM engineers.
ORIGINAL: Trock
Yes it says that in the book. It also says Never use after market parts on your Harley. Page 5 says don't operate with the forks locked. I didn't expect HD to say yes it ok to change wheel size. The sensor is in the bearings, after lots of checking I'm going to keep mine 21/18's
Yes it says that in the book. It also says Never use after market parts on your Harley. Page 5 says don't operate with the forks locked. I didn't expect HD to say yes it ok to change wheel size. The sensor is in the bearings, after lots of checking I'm going to keep mine 21/18's
Also, it factors original (as designed) contact patch and tire compound (within a threshold).
You could be looking at two scenarios:
1) the ABS kicks in way too late, after the tire(s) have slid enough to get you into some trouble.
2) the ABS kicks in way too early bleed off some braking energy and ending up with less braking efficiency over all.
You do *not* know more than the OEM engineers.
So the engineers got it right in 07 with the heat and no IDS? I assume we shouldn't use anything but HD oil? Anyway after talking to a couple wheel makers and hogpro I decided to try it. The brakes work great with no abs light, and I've tried locking them serveral times. I've changed wheel sizes on cars and know others that have with no problems. If you don't want to change don't. Thanks to the person for the warning but I decided to change.
Road Master
Joined: Mar 2006
Posts: 1,143
Likes: 0
From: Snowflake, Arizona
RE: ABS - Watch Your Modifications
Rumor has itthat if you get a flat while riding, the sudden change in the tire diamterwill also upset the system.... and there will be no brakes if you try to get stopped becausethe HD computer is written to read that you ignored page 5..... and revenge must taken foryour failure to follow page 5....
Later
Later
Elite HDF Member
Joined: Oct 2007
Posts: 4,523
Likes: 1
From: South Florida
RE: ABS - Watch Your Modifications
Thanks[sm=smiley20.gif][sm=smiley20.gif][sm=smiley20.gif] to all the "Engineers" is why I have such a great job that pays big $$$$$
Fixing all their screw ups and handling recalls.....
Fixing all their screw ups and handling recalls.....
Cruiser
Joined: Apr 2007
Posts: 204
Likes: 0
From: Atascadero, CA
RE: ABS - Watch Your Modifications
I have to agree with Panioloon just how sensitive the ABS actually is. I think that we would all agree that the primary purpose of ABS is to prevent the wheels from locking up at speeds over 5 MPH. The sensor is oblivious as to the diameter of the wheel that it is attached to it and is just reading the magnetic pulses as the wheel is spinning as the brakes are applied. As you apply maximum breaking to both the front and rear wheels the sensorsare monitoring each wheels rotation independently. My rear tire allways wears out long before my front tire does so the rotation synchronization of the front and rear tire is not in tune during normal wear on the tires. I have never put anything other than a stock diameter tire on my bike because I wouldn't want it to mess up my speedometer calibration, but I would not think that it would prevent me from stopping effectively if I chose to change it. I'm not an Engineer, Just my opinion.
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Tourer
Joined: Sep 2005
Posts: 305
Likes: 1
From: pittsburgh
RE: ABS - Watch Your Modifications
Manuals have to go past the legal department. Engineers write them, lawyers edit them. Then accountants get together and slap each other on the back for having a good year.
H-D has never had a model with an 8' girder front end, turbo or 400mm rear tire. The lawyers and accountants said no.
H-D has never had a model with an 8' girder front end, turbo or 400mm rear tire. The lawyers and accountants said no.
RE: ABS - Watch Your Modifications
ORIGINAL: Roadhog02
I have to agree with Panioloon just how sensitive the ABS actually is. I think that we would all agree that the primary purpose of ABS is to prevent the wheels from locking up at speeds over 5 MPH. The sensor is oblivious as to the diameter of the wheel that it is attached to it and is just reading the magnetic pulses as the wheel is spinning as the brakes are applied. As you apply maximum breaking to both the front and rear wheels the sensorsare monitoring each wheels rotation independently. My rear tire allways wears out long before my front tire does so the rotation synchronization of the front and rear tire is not in tune during normal wear on the tires. I have never put anything other than a stock diameter tire on my bike because I wouldn't want it to mess up my speedometer calibration, but I would not think that it would prevent me from stopping effectively if I chose to change it. I'm not an Engineer, Just my opinion.
I have to agree with Panioloon just how sensitive the ABS actually is. I think that we would all agree that the primary purpose of ABS is to prevent the wheels from locking up at speeds over 5 MPH. The sensor is oblivious as to the diameter of the wheel that it is attached to it and is just reading the magnetic pulses as the wheel is spinning as the brakes are applied. As you apply maximum breaking to both the front and rear wheels the sensorsare monitoring each wheels rotation independently. My rear tire allways wears out long before my front tire does so the rotation synchronization of the front and rear tire is not in tune during normal wear on the tires. I have never put anything other than a stock diameter tire on my bike because I wouldn't want it to mess up my speedometer calibration, but I would not think that it would prevent me from stopping effectively if I chose to change it. I'm not an Engineer, Just my opinion.
I agree with the above quote, the ABS is activated just about when the wheel stops spinning, which it picks up via the sensors. It is not so sensitive that to make small changes to tyre size, change tyre makes, etc. will make any difference.
WB