[tanshi]

Trying to get some firm facts on what number of teeth are on the various sensor rings of GVs and Jimnys.

From what I can tell so far:

jimny rear is 38 teeth

GV front is 53 teeth

[tanshi]

also does any one know if the number of teeth on the rings has any great bearing on how the abs works.

i.e if I went from a 38 tooth to a 45 tooth would it throw errors?

[pete_79]

According to the manual; the ABS can throw alarms just by driving on sand or mud and spinning the wheels.
By that I would assume changing the number of teeth could cause issues.

Nothing in there about number of teeth front or back, but it's pretty clear in this pic that they are much bigger in the front.

[tanshi]

they are bigger. but they also have more teeth front to back.

so that says to me that the difference in diameter equates to the wheels spinning at different speeds and thus pulsing at the same speeds?

[pete_79]

One would ASSUME that your logic is correct and there would be more teeth on the bigger rings to give the same gaps for each sensor.

But like they say, assumption is usually the mother of all fuck ups.

[tanshi]

or maybe its to do with brake bias to the front. arrgghh annoying

[alien]

If you place a 38t gear on top of a 53t gear there's going to be very few teeth that directly line up (exactly 100%) - spinning them at the same speed the difference would remain. The only thing that would affect it is the rolling diameter of the tyre - a GV has a larger wheel/tyre combo than the jimny.

Base Model GV comes with a 28.4" Tyre
Upper Model GVs are a 30.4" Tyre
Jimny is 26"

There's clearly a margin for error though - if the GV runs a 7% larger tyre between model specs. One would assume suzuki don't update the software between these models? Although that likely also means the speedos are out 7% between models too.

[tanshi]

they run different amount of teeth front to rear.

[alien]

If you plugged the pulse data into a computer though it'd work out the difference pretty easily though? It could be to do with available space on the rear / front that influences the size difference rather than any brake bias. Brake bias would be done by the computer knowing if a wheel has stopped or not. You wouldn't limit how often it's pulsed as you'd want to have the quickest reaction time possible.

[SierraDan]

What are you trying to achieve?

[tanshi]

im looking at how the abs works for floaters.

I don't want to have to run the normal ring that presses onto the axle shaft if I can help it.

thus running the front hubs and rings on the rear would be ideal

I have seen some pics where job had done this design on his but im not convinced it is a good idea.

[tanshi]

the problem as I see it is if the computer is smart enough to freak out if the wheels are turning at different speeds, then making the sensor ring on the back bigger than standard will throw an error light and do god knows what to the brakes

[pete_79]

I figured you where working in something that might interest me soon enough.

I went and had a look at our Jimny when the misses came home from work.
If it was as easy as ripping the wheel off and counting the teeth for you I would have. But it's not......

[tanshi]

Yeah the ring sits behind the disk rotor

[Mike57]

Tanshi

I looked at this a while ago when I was considering a full floater rear and concluded that the number of teeth is probably not important and the ABS computer probably just compares the rates between both rear wheels. However, my concern was related to the brake proportioning and how the ABS would respond to a different rear brake cylinder type and pressure. I never got a clear answer to this one so if you do get this working I would be most interested in your findings.

Mike

[alien]

^^ That's a fair point - however it could affect the aggressiveness of the ABS - ie: If the system is picking up a fast pulse it may do faster pulses of the ABS (ie: it knows you're going faster so wouldn't want the wheels to skid for a long distance), where as at slower speeds it'd be able to brake harder for longer to stop quicker??? I'm just guessing... maybe someone can find some gravel and test it out at different speeds to see if it pulses the brakes differently at different speeds?

[pete_79]

I've had the ABS working a few times at high and low speeds on different surfaces. It always feels the same under foot.

I have a theory about safety features like air bags and ABS in budget cars such as Jimnys.
And I really don't believe they are as advanced as you are suggesting there alien.
I believe it's more like the sensor works within set parameters, once it goes outside of those the computer activates and pulses at a set rate to 'help' stop the brakes from locking up.

More advanced modern cars may have more advanced or intelligent ABS systems. But we're talking about a 15 year old car that they've slapped some extra things on to meet the safety rules of the time so they can keep selling them.

[tanshi]

I doubt the proportioning thing would be an issue. You would use an adjustable prop valve as you do on a sierra and the abs wouldn't know any different

[tanshi]

I guess I need to find a guinea pig to test it

[Gwagensteve]

Proportioning should be redundant with 4wheel antilock. I don't believe any car with 4wheel antilock runs a proportioning valve- the abs does that job more effectively than a prop valve could.

[tanshi]

Fair enough I guess that's true Steve.

I have just spoken to Joeblow. He says the tooth count is irrelevant as the computer only uses it to determine if the wheel is turning or not.

As he has don't the ABS before i'll trust his judgement.

Looks like it should be pretty easy to do these now.

[smiley_666]

All the abs sensors do is measure individual wheel speed by modulating the pulse width of the signal sent back to the abs brain. Ie, if it came with 53teeth, the computer will have a hissy fit if it is seeing a signal from a different number of teeth which will mimic a differing wheel speed. The overall size of the tone wheel is just for packaging, its the teeth count that matters. So if a car comes with 2 different teeth counts, then the computer is programmed to figure out the wheel speeds based off the differing counts.

[tanshi]

and as I said above. the tooth count doesn't matter in the GV or the JIMNY as tested and proven by Jowblow

[Jezza86]

hyjack: if its a problem, could it be corrected with a linear frequency modulator to take frequency B and fudge it back to frequency A?

[tanshi]

guess that's possible, and I know just the guy who could do it.

[Jezza86]

actually that's probably what the jcar kit does for the speedo for 40 bucks... http://www.jaycar.com.au/Automotive-%26 ... E/p/AA0376

[sezed]

FWIW, here are some pics of the abs sensor rings for the rear axle and the front hub from a 2004 GV, Back to front are quite different in design...

[Rhinoman]

If you have too many teeth the I suspect the ABS computer will throw an error if it thinks its doing 200mph and the ABS won't work properly at low speeds if there aren't enough teeth.

[tanshi]

Sezed? any chance you counted the teeth?

[sezed]

Nope, but I can pull them out tomorrow and have another look...