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This is what a tire shop just told me would happen if I went from a 245 to a 265 on the Rodeo. He said the ABS sensors would not work properly and that the ABS might not kick in when I need them. Is this true?
 

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No this not true the abs does not know what tire you have it only senses if the brake lock up all it does is pulse do stop tire lock up under heavy braking. the only thing that it will do is throw youre speedo off about 1 or 2 mph or so but mostly on the freeway so no worry's there, the only thing you might think of if you go up a few more sizes is the brakes them selves for youre size diff you will be fine but if you do need brakes after you put on the new tires you might look into a better pad like a mettalic it will help with the bigger tires but if you go bigger yet you might want to look in to a slotted rotor and so on. as far as you' re set u you will have no issue's at all with you're abs so good luck.
 

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No it will not if you go from a 245 to a 265 it is only about a 1/2 inch to 3/4 change and it will not care if you do it. I have done tons of lifts on brand new trucks and i am going from 285x75x16 to a 35x12.50x16 or even bigger like a 39.5 tsl bogger on my personal 01 ford superduty and it still has the abs and it works just fine, if you dont belive me call the chevy - ford - dodge or what ever you prefer and ask them if you put a lift on a truck if you have to yank out the abs because it wont work and they will tell you to leave it it will be fine , or ask someone witha jacked up fullsize if they are having probs with there abs
 

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Chevy/ Ford/ Dodge/ jacked up full sizes do not apply to this discussion. We are talking about ISUZU's abs system. And the general consensus of the people who actually have larger tires on their ISUZU's is that it is affected. Yes the larger you go, the more out of whack it will get. Alright I'm done with this.

mike
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ABS , gets fed the speed of the vehicle, so if you have different sized tires , (in terms of the final diameter) then it will not react exactly the same way, because the speed 'data' it is not accurate.

If the tires are 'bigger' , then the speed will seem 'slower' than it is to the ABS system, and thefore it will not necessarily 'activate' because it thinks you are driving slower than you actually are.

the only way to really know is to test how it performs , because they 'tweak' the abs parameters based on the tires it comes with , and it varies model to model year.
 
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just a note on the above, it does correlate with the amount of change !

there should be however a way to correct the speed data, usually the main ECU is programmed with the tire size, so maybe jetchips could custom program it for you .

of course a very difference would hardly be worth it !
 

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Most all abs sensors (except those on very high end cars: read mercedes bmw etc) have a sensing ring. This ring looks essentially like a very fine toothed sprocket (around the order of 20 teeth to the inch). When the sensor sees lock up on the ring it activates the abs. It can sense this, usually optically, in one or two teeth. This happens regardless of tire size. If you still question this think, about a catastrophic tire failure. The car is designed to still have operational abs in this scenario even though you now have a 4-6 inch diameter change.
 

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Ok, I will say this.....

tire size shoudl not affect the ABS it self.....ina linear thought...

i know the controllor on GMs isnt affected by it.....(been there, done that)...

BUT, on both of my Rodeos, going to 33s wreaked all kinda of havoc(even throwing a light on my 00), went back to my 245s, and presto... reset the controler..and there it was....

Hooked the scanner up, and the speed sensor, and the tone rings noticed to great a variation in speed(further checking revealed int his instance, a substatial circumfrence difference in front to back tires). The controllers have parameter to account for tire wear, but buy increasing you size, you reduce that parameter....

Solution, remove your ABS fuse, adn cover the light.... OR find a shop that will re-cal your PCM for the tire size you are running, and go from there...

DISCLAIMER: I have hated ABS from the start, and I always eventually by-pass it anyway, and no, there is no safety issue involved...BUT, thats me.... And individual results MAY VARY..... but in my case, the results were similar...

Anyway, my 99 isnt nearly as bad, though, it too has been bypassed at this point....

Why the difference? Its all in the programming.... BUT, in theory, BigAmigo ir right...but, for fact.... in the later Rodeo/Passports, its does wreak some havoc..it also seems to depend on the tires run... We run Swampers....could they be the factor? Dunno..dont care...
 

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could this cause a large thunk in the rear when braking. i put 285x75x16 on my 92 trooper about 6 mos ago and it has started a thunk when i came to a hardish stop it only thunks after a complete stop and when i let the brake pedal off. ive been trying to figure it out to no avail. i have even checked for loose bolts and all. and if so where is this fuse.

thanks
 

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Well, I dont think so...BUT.... check for worn bushing in the rear links, particularly, in the 3 that go from the axle, FORWARD to the frame... than, pull the wheels, adn pull the brakes apart, adn lube all the metal to metal friction areas...and go from there....

I have this same problem in my 99, adn have done evrything short of rebuild the rear end.....guess whats next......new ring and pinion with an ARB....maybe....who knows....

But, again, try those things first, and go from there.....

Chase
 
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