20' rim's good or bad ????

think about putting 20' rim's on my 1999 S10 BLAZER 4X4....Will this effect my speedo...or the Odo??? And if so....What size tire will work ... I would like too use a truck tire not a car trie?????:banghead:

By changing the size of the tire and rim you affect the diameter of the wheel. This will affect how many revolutions there are per mile, which affects the reading of the sensor that feeds to the speedometer. You are actually going to be traveling faster than is indicated by your speedometer if the wheel/tire combo has a larger circumferance than stock. This will also affect the mileage that you show on the odometer (as it is based upon the readings from sensors that are affected, also).
You should have your speedometer recalibrated if you change from the stock configuration to an aftermarket.
THis will proably affect your MPG's also, in a negative way.

You can also get a tire that has a lower profile. If you keep the diameter of the tire (outside that is) the same you will not change the speedometer readings because it will be spinning the same rate as the oe tires. I think tirerack.com has a tire size calculator that can do the math for you

My 2cents
http://www.dsm.org/tools/tiresize.htm

And......
http://www.tire-covers.com/catalog/tireguide.htm

20 footers (20'), don't think that fits . 20 " maybe with some 20 series tires . difficulty when turning though . Rob