After switching my springs and adding lift blocks I decided to go up a few sizes on my tires to add a little more lift and to improve the appearance. Did a lot of measuring and hem hawing about which ones to get and these seem to really fit the bill. No rubbing of the tires when you do a sharp turn and just enough clearance so that the back wheels don't touch. The ones I choose were the 205/70/15 tires. Got a pretty good deal on them through Amazon and the difference in the ride is like going from a model A Ford to a modern Buick it really is a drastic change for the better. As far as changes in the gearing when my speedo reads 70 MPH the car is actually going 74 MPH which is a pretty nominal amount. How this will effect MPG is yet to be seen. The tires I bought are supposed to be made with more silica for better roll resistance and I aired them up to about 44 psi so we shall see. I loaded the pictures in order of what height I started out with then the height after I changed the springs and added lift blocks then finally with the new tires installed. If anyone has any questions just ask and thanks for looking.
It’s roughly 7% reduction in revs per mile. Speedo is a little high to begin with. Addendum: The odometer, which should be reasonably accurate with the stock tries, will be under-reporting the miles by that 7%.
I don't know yet I just put them on like 3 days ago. I am hoping that the higher gear ratio will cancel out the extra drag or at least come close. When I go out over the road November 1st I will post the solid results.
You are correct sir and if there is any serious adverse effects I will report it here. Consider me the canary in the coal mine.
Higher gear ratio usually don't work to your advantage in low horsepower economy vehicles. I'm willing to bet you'll come in at less than 30mpg.
I'm going to do a couple hundred mile test with a mix of highway and city before I head out over the road to check the average mileage. I did about 41 mpg last year so i doubt it's going to be a 10 mpg loss but we shall see.
Ok the data is in on the bigger tires fuel economy question. Went on a 90 mile trip down to the Ohio river and back using a GPS speedometer/odometer app to get the legit mileage. To make a fair comparison to how I travel when camping I attached my travel box and tossed a full size tire in the back. It was still about 150 lbs lighter because my camper platform is out of the car during renovations and my 12 volt refrigerator/freezer is not on board or my tools but it's close enough. Knowing the Prius speedo and travel computers are off I simply filled the car up with fuel drove the 83.37 miles on the highway then refueled at the same station when i got back Here is the math 2.13 gallons of fuel divided by 83.37 miles driven comes out to 39.14 mpg. Fully loaded and using the AC on low I will probably get 37-38 highway depending on terrain. Considering all the things I can now do because of the added clearance with the new lift and tires I am chalking this one up in the win column. I have yet to test the city mileage but I will and I will post the results here but that is maybe 10% of what I drive when I go out on the road so no worries. Follow me for more crazy Prius recipes!
Did you check GPS against odometer, compare the two? Would be good to know that ratio. n’mind, it’s in your pics.
Yes sir, and your 7% prediction was just about dead on. There are so many other variables as far as gas mileage but I drove the way I usually drive and I was pleasantly surprised at the results. Did 9K miles all across the US last year and averaged 40/41 MPG so 39 is not looking bad. The tires I put on are almost 2 inches taller and almost 1 inch wider but I overinflated them and they are allegedly made with more silicone and have less roll resistance which seems to be panning out. The bullet point of my presentation is that people should not be afraid of taking chances when it comes to modifications. I feel like I have added a new chapter of knowledge at the PC "Library of Alexandria". I use my Prius as a camper and do mostly highway miles so this mod was the right one for me. It might be a disaster for someone else with other goals. I will be tearing it up starting November 1st heading to the pacific northwest this time. Going to spend time on BLM land and forestry service land and dirt roads and the desert. All the places I wanted to stop and drive down and camp in 2021 but was sitting 4" off the ground and couldn't take the risk. At the end of the day the money I save using my Prius as a camper/Motel will more than make up for whatever petty MPG losses that come up today's research proves it.
I went with an Amazon seller called (Complete Struts) where I bought both new Prius struts and Pontiac Vibe struts to do the build. Your best bet is to go back to the beginning of this thread and start reading as there are a few different ways to do it. This thread Heavy Springs And Lift Upgrade | PriusChat
I also got the tires from Amazon they are the Falken Sincera SN201 A/S All- Season Radial Tire-205/70R15 96T the lift blocks came from E Bay I got the 40mm kit.
Those Falkens are supposed to have lower roll resistance than your average tire but who knows? Falken Sincera SN201 A/S 215/60R16 95T All Season Tire - Walmart.com