I have been thinking about putting 37x12.50r16.5 tires on my trock with summit rock crawler tires i have 5.29 gears and a 4-5 procomp lift and a 3 in body lift. i have a military base 100 miles away with tires so i was thinking about trying to purchase some tires for my truck stock ifs with 5.29 gearing should i do this before trying to pass smog in ca or should i keep my 33x12.50r15 on i have also been looking into isoheet or 99% isopropyl alcohol to help it pass. so should i put bigger tires on or keep the small ones? which one will help me pass smog with better numbers thanks in advance

 

100 views and nobody knows anything?

 

Does your truck not pass smog now? If so, I don't think tires will help, and I'm pretty certain adding alcohol will only make things worse. What numbers do you get?

If your truck passes smog now, changing the tire size will change the rpm and engine load at the testing speeds. But I've never heard that has any significant effect on emission numbers.

 

okay thanks In Ca I don't want to be labeled a gross polluter And thanks on the alcohol I have some lying around 99% and I believe it will struggle to pass as there are some problems and hopefully i will be able to fix some of them to allow me to pass. Just so you know i have 33x12.50r15 with a 5.29 gear ratio.

 

Try this thread http://board.marlincrawler.com/index.php?topic=1119.0

that helped me out a lot

i got mine to pass since i installed a new cat on it, walker cats are like 100-150 its a small investment to make a car pass smog


my truck was labeled a gross polluter in California and after I swapped the cat it passed real well

use rockauto.com or partsgeek and use exhaust gaskets from the autostore not that come with the cat