GenVibe - Community for Pontiac Vibe Enthusiasts

I'm thinking about going with a larger wheel and tire combo to reduce my highway rpm's. I dropped a 6spd in my base vibe (replacing the POS 5 speed when the notorious bearing went bad) and I am taking a hit on the mpg due to the higher rpm's with the 6spd. I would like to stick with something stock so that I may search the local yards to keep the cost to a minimum. I'm not into anything fancy, just practical. What size wheels shipped on the GT's? Or maybe there is another wheel off another GM/Toyota vehicle (G6, Grand Am, etc.) that would work? What size could I bump up to without any body mods/spacers/rubbing?Thanks in advance for your input.Mike

I have a hard time believeing the final drive RPM on a 6 speed is higher than the final drive on a 5 speed.at say 70mph what rpm are you at?GT's are 18" rims. However they have the same total profile size as the base model 16" wheels

I was told or read someplace on here that the 5th gear in the 6 speed is like the 4th gear in the 5spd and the 6th gear is a higher numerical gear ratio than the 5spd's 5th gear. Maybe someone will pipe in with the numbers...On edit: I found the thread with the final gear ratio numbers and the 6th gear is numerically higher than the 5th gear in a 5 speed. Look at the 2nd entry on this thread: http://forums.genvibe.com/zerothread?id=41342

What are your MPG's and what speed do you normally travel? If you're getting 28mpg with cruising speeds of 80mph, you're doing ok!

I haven't checked it since I did the 5 to 6 spd swap. Honestly I'm afraid to check it since I was getting around 32mpg hiway with the 5 spd and now with this 6spd winding right up there... well, you know....

Stock wheel size on my '04 GT is 16", not sure about newer models.

Not only a matter of rpm but you would endup with an underestimated speed read on the speedometer resulting in potential ticketting if you drive close to the speed limit. Its not suggested to go higher or lower than the stock diameter.

That's why God gave us the GPS

the 6 speed 6th gear ratio needs to be a bit wider to get better gas mileage. either that or make a 7 speed. it's already 0.96:1 anyways.