M796ABS - No Gearing Changes

[arai_speed]

So I was reading this topic on DucatiMS:

http://www.ducati.ms/forums/showthread.php?t=93256

And according to the OP it seems that gearing changes on the M796 with ABS are not applicable.

He even posted the response he got from DNA:

"...The ABS system uses both speed and RPM in its computations, two things directly affected by changes made to the gearing ratio. The ECU that governs the ABS system is programmed to work with the stock gearing on the bike only.

We hope this provides you with the information you were after.

Regards,

Customer Service
..."

Very interesting.

[Amlethae]

Uhhhhhhh..... what?

I've put a 14T sprocket on my 1100S w/ABS and the ABS is working just fine.  Certainly they realized that at least some of the time you will be needing ABS, you will have the clutch lever pulled in, so the gearing is rendered irrelevant... 

Computation wise I can see MPH being a factor as well as the speed of the two wheels... if it senses a wheel halting too quickly it releases the brake to keep it from locking up.  I can't imagine that the gearing of the bike has any effect on that what so ever.

Who ever wrote this email may well have been thinking about Traction Control which would indeed need to know the gearing of the bike.

Maybe I'm just talking out of my ass here, but my ABS works just fine with non-stock gearing... and I can only assume it's the same system on the 796.

[libertarian]

The problem is that Ducati says you can't put them on ABS models, so even if they work, you're asking for major warranty headaches if they cause a problem with anything... In 2 years, it'll be less of an issue, but I'd hate to have something go wrong on my brand new bike and have Ducati say "Oh, that part wasn't approved for the bike, it screwed up the engine, so sad to be you."

[Bill in OKC]

Doesn't Ducati have the speed sensor on the rear wheel, sensing the brake rotor bolts?  I know the Japanese manufacturers sense how fast the countershaft sprocket is turnng...  If the bike's speed is picked up off of the wheel, gearing will not have any effect on the speedometer.  I guess RPMs would be different for the bike's speed but does ABS sense which gear you are in?

[Amlethae]

The problem is that Ducati says you can't put them on ABS models, so even if they work, you're asking for major warranty headaches if they cause a problem with anything... In 2 years, it'll be less of an issue, but I'd hate to have something go wrong on my brand new bike and have Ducati say "Oh, that part wasn't approved for the bike, it screwed up the engine, so sad to be you."

The dealership installed the 14T sprocket before I took delivery of the bike... if that doesn't work with the warranty I know my argument :-)

Doesn't Ducati have the speed sensor on the rear wheel, sensing the brake rotor bolts?  I know the Japanese manufacturers sense how fast the countershaft sprocket is turnng...  If the bike's speed is picked up off of the wheel, gearing will not have any effect on the speedometer.  I guess RPMs would be different for the bike's speed but does ABS sense which gear you are in?

You're right about the speed sensor for the MPH of the bike -- gearing doesn't matter because it knows the size of the wheel & tire and it's measuring the movement of the wheel bolts and calculating that against the pavement to find distance... the way Archimedes designed it.
Each wheel has it's own sensor rig for the ABS system... looks like another rotor but with lots of little notches in a small wheel.  Again, all the ABS is doing is watching those notches to make sure they don't slow down too quickly, if so it releases the brake and reapplies to prevent wheel lock-up. 

My ABS kicked in yesterday btw as I was trying to avoid a stupid driver that didn't stop for me, the ABS worked just perfectly and doesn't engage unless necessary.

[ducatiz]

That's not how warranty claim denials work anyhow, at least not in the US

[ungeheuer]

That's not how warranty claim denials work anyhow, at least not in the US

Sooooo..... how do warranty claim denials work?    Short question.... Possibly long answer.  Sorry.   I imagine in this case, if you fitted a different sprocket having been advised that it may effect ABS function (but probably actually doesnt - just a catch-all ass covering statement) you'd have um... limited rights persuing Ducati for failure or malfunction of the ABS.   But that would be the limit of the limitation, would it not?

[zootsuitbass]

Any updates on this...I just bought a 11 796 ABS (used) and the having the dealer do 600 mile service. 14t is on the menu. They gave me a warning, how serious is this...Check engine lights??? ECT???

[Curmudgeon]

Any updates on this...I just bought a 11 796 ABS (used) and the having the dealer do 600 mile service. 14t is on the menu. They gave me a warning, how serious is this...Check engine lights??? ECT???

There's another thread on the DMF which quotes a retraction of the above from customer service at DNA. Fit the 14T. You will LOOOVE it.  See: http://www.ducatimonsterforum.org/index.php?topic=52528.0

[Arachnosold1er]

I was going to put a 14T on my 796 when I first bought the bike. I have over 3K miles now and the engine has "relaxed" some and the low speed shuddering is nonexistant.  Riding in traffic is a lot easier now.

[TNWINESELLER]

I have a 2011 M796 w/ABS. 14t front sprocket installed by dealer. No braking issues

[EvilSteve]

My wife's M796 has a 14T front, it was double checked by my dealership to be ok. They said yeah, then no and then went to Ducati to ask and came back with yes. I also have a 14T on my M1100EVO and it's also fine.

[loopsrider]

If the EBCM solely uses engine RPM and wheel speed as inputs, then of course it will  not be getting the proper readings and will not perform the proper calculations. Seems weird that engine RPM would be such an important input on a bike. A quick look at the EBCM inputs on a schematic would eliminate any question.


If so...Will it be noticeable in daily riding.... probably not...

Will it be noticeable in a panic ABS situation... let us know when it happens...


I get this question all the time at the auto dealership I work at in regards to changes in tire sizes. My response is that it may affect ABS performance... Do you want to be thinking about that when a kid runs out in front of you after his ball and you rely on ABS to eliminate wheel lockup and allow you to steer... Your call....