what's going on blazer fam. I got a question, I got 20's on my 97 chevy blazer and everyone is telling me I'm messing up my transmissions someone please school me on the whole rim theory

 

Welcome from an other forum newb.

You only have 1 transmission, I am curious about this "rim theory." What kind of damage is "everyone" telling you this will cause.

As long as they are the same size I can't imagine how it would be a problem, but nothing surprises me anymore.

 

20's will mess up the calibrations for the speed, shift points, odometer etc.

 

Welcome to the forum

No damage should be done to the drivetran that i know of

your speedo must be off a bit but thats all

 

Damage - No. Get a friend with a stock vehicle to drive beside you, yap on the cell at certain speeds & see what yours reads compaired to theirs.

I'm not too sure what a '97 has in it for a trans but the speedo, odo & shift points will be messed up if it has a 4L60E trans. That will effect the engine as well with the ECU/BCU of the vehicle (in my case anyway). The E at the end of a 4L60E stands for Electronic as far as i know (oops sorry pettyfog) AFAIK ;-) & that means things will get fubared as for ECU or BCU readings & that effects all the other things down the line. Like an AIT being disconnected & how that effects an engine, or MAF etc. They all mess up other parameters down the line when 1 isn't right.

Taller tires will mess up the speedo, trans & odometer unless they have a gear replaced on that type of trans or have the ECU recalibrated for the taller tires.

 

whoa so should i get rid of them, and do you get the speedometer checked im getting a new tranny now and im paying good money for it this time i dont want to waste it

 

You can get a scanner that plugs into the OBII port & set up the tire changes. Hypertech programmers can do it & most shops can as well.

 

so keep them or sell I love my 20's but if there going to cause trouble I don't want them

 

It has already been said a couple times, it wont cause any REAL problems, The only thing that will be a "problem" is your speed will be off, your odo will be off, and possibly your shift points too. But honestly, Measure the height of the rim and tire on your 20's, and the rim and tire on your stock 15's and see how much of a difference there is. It really cant be that much