Not sure it's the right answer: change to 16 wheels with 175/65/16. Do they even have this tire size?
When I had a Yaris 3-door, I got a deal on a set of used Scion XD wheels with tires. It gave me increased ground clearance. Didn't measure, but you should talk to a tire-salesman. You can always sell your existing tires to offset the cost.
Increasing tire rolling radius by an inch is an incredibly bad idea. Do not do this nor recommend this. In addition to significantly changing the obvious things (torque and rpm for a given speed for example) it also dramatically impacts the moment on the suspension components AND its geometry. You don't notice this, but as the car moves up and down on the suspension the wheels do not remain perfectly vertical. That is, in part, so that the contact point does not scrub in and out as the A-arms rise and fall. This is basic suspension 101. Small changes, like from treadwear, don't make much difference. An inch (!!!) would do all kinds of nasty things. Not that I'd do this, but this is what a lift kit is for. If you must do what you want to do, find someone who actually knows, or can get, the Prius suspension geometry to work this out for you before you do it. It may be that you can increase somewhat your ground clearance without raising your ride height, and then do the rest by a small ride height adjustment via lift kit. But again, increasing wheel diameter by that much is a very bad idea.
Cheapest way is adding rubber spacers between upper coils when the wheel is off the ground and coils at maximum separation. That wuill also stiffen the ride as well. However, that also means the car is easier to turn over in corners as well as requiring wheel alignment. Second and really the best way is to change wheels and or tires. For instance going from 175/65x15 tires to 195/70x15 tires will add about an inch to height. Or goung from 175/65x15 to 185/70x16 tires will add close to an inch in height (2" more tire diameter) but the same caveat about cornering tipmover applies. Why do you want more ground clearance?
Those attributes really do not apply to raising the ride height by an inch. The motions of the suspensions remain essentially the same. And you won't increase your ground clearance without significant, horrendouly costly. body changes (think Dakar rallies) or without increasing tire/wheel diameter. The lift kits the offroaders use have lifts significantly greater than 1 inch and many susprension and alignment changes are also needed. Again.hy do you want an inch more ride height?
\Nonsense. Changing ride height by an inch is no problem other than making a vehicle easier to turn over in a corner.We do it all the time for cars though for every ride height increase we do for off roaders we do 10 lowering work for performance typres..
my c1 rides just a little too low over speed bumps. we in hawaii (big island) get horrendous torrential rain forest rains. there is flooding, mud, sharp lava rocks and ponding in the road. by the way the EXCELLENT Turanza EL400 Bridgestone tires are wonderful in these rains !!! and looking underneath i can see that the rubber undershields are held on by only a few plastic pins. its hard to beleive it all holds together so well driving 55mph in these rains. an inch higher would gain back some of the height lost when my c1 is laden with 5 passengers and my poi dog chihuahua.
i read many posts here. so i went ahead and increased my tire pressures to 40psi all around. car sits much nicer. interestingly the suspension responds with a better ride than when the tires were at 34~32psi. i think i may post this separately to share this ,,,
LOL on the Huge diatribe on safety on the larger tires. Biggest downfall would be speedometer inaccuracy as well as increased brake wear (minimal). Try xD springs as we share a LOT of suspension with them, (may be, probably not longer/the same) Buy an xD /Yaris specific RALLY designated coilover setup it will go HIGHER than stock with an adjustable damping AND ride height. Air suspension can generally be setup to be HIGHER than stock as well. Only other options would be pretty ghetto and would include using spring "helper" clamps. they basically spread two coils further apart thus removing the droop and thus giving you a small amount of ride height. Best suggestions in all reality are tires, air suspension, rally coilover system.
