Downsized from 19" to 17" and somehow... ride quality is worse?

Are the suspension pucks from shipping removed from the coils? Sometimes those are missed.

Did you try that? How was it? What was the impact on your trip mileage?

Was your last car a small Toyota? I had a Corolla Hatch with CC2s I wore through pretty quickly, but I hadn't any ride complaints. I have the 17" Toyo Extensas on the Prius at just under 40psi. I would describe the ride as soft, but I'm a small car guy.

 

I haven’t seen anyone on here do any objective testing but here is a screenshot from consumer reports comparing Toyo Extensa A/S II and Michelin Cross Climate 2 both in size 215/55 R17.

 

It's not the drop down to 17 from 19, nor is it the tire load rating that's the problem. It's a combination of two things:

1) lower profile of 55 on top of reduction of two inch diameter means there's way less tire absorbing the bumps in the road. Had you gone with a profile rating of 65 or higher I bet it would of been way better.

2) Prius have always been designed to work with low rolling resistance tires and you made the common mistake of choosing tires that were designed to maximize traction in bad weather, which has a much deeper and softer tread and that's a bad tire if you want a smooth ride in the summer time. What's more, its going to cost you thousands of dollars in lost MPG over the lifespan of the tire.

Hopefully the people you bought the tires from can at the very least confirm the install was done properly with no defects to the tires. Or at the very best let you switch to some 215/65R17 Low Rolling Resistance (LRR) tires for a minor upgrade fee or for free.

 

The lower the outside circumference, the deeper the tyre will fall into a hole rather than ride over it. That sounds like the ride you are feeling compared to the larger circumference tyres.

as PriusCamper has posted, reducing the side wall height will also reduce the "give" available for the tyre to take up the smaller bumps, the bigger holes will take up all the "give" available in the side wall and damage both the tyre and the rim.

Low profile small sidewall tyres are for super smooth surfaces, even the join in the concrete slab roads feel like driving over ripple strips ......

T1 Terry

 

Strawmochi has moved from 19 inch wheels with very little sidewall to 17 inch wheels with much more sidewall.

I believe you have something reversed.

The 17 inch wheel with a 215/55/17 tire has more than 20mm more sidewall than a 19 wheel with a 195/50/19 tire. The stock Toyota 17 inch wheel with 195/60/17 tires will have about the same sidewall depth as 215/55/17 tires.

That tire would have a 28 inch circumference, an inch and a half more than any of the stock wheels and tires.

 

Ok, then go with 195/65R17. I don't understand why you're putting your trust in Toyota's judgement when it comes to tire size and tire quality? The have a well established reputation for making horrible decisions about tire size and especially tire quality.

And again if you're going to buy a tire for winter weather and complain that the ride is awful in Summer then you failed to buy the right tires, which is the point of my reply.

As for what the very best tires are for Gen5 for best MPG and most comfortable ride, that's something worth starting a thread about. This thread is explaining why his ride got way worse and uncomfortable because he bought the wrong tires.

Main point is lower profile tires = less comfortable ride

and as @T1 Terry points out:

Smaller diameter wheels = more tire going to the bottom of a pothole

 

I don't think you're actually reading what the OP wrote.

They went from a 195/50-19 to a 215/55-17. That's a 23.7% increase in sidewall height. From 3.8" to 4.7". It's even a tiny bit more than the 4.6" sidewall on the stock 17".

And thousands of dollars in lost mpg? What are you smoking? The CC2 has one of the best rolling resistances in the all-weather category. Not as good as a dedicated economy tire, but still acceptable. The OP had the 19" wheels. That's about 48mpg/114mpge stock. A 17" CC2 is going to get about the same mpg. It's wider and has a higher RR, but it has overall lower unsprung weight because of less metal in a 17" wheel vs. the stock 19" wheel. So they're going to get about the same mpg. If they had gone with the stock 17" size wheel and tire, they'd be looking at 52mpg/127mpge. Both the CC2 and the stock Toyo are about 40k mile tires depending on conditions and driving habits. That's roughly 833 gallons of gas used for the CC2(assuming no EV mode - which is unrealistic for a Prime) vs. 770 gallons for stock 17" Toyo for a difference of roughly 65 gallons over 40k miles. If we use the MPGe numbers, it's 350gal vs. 315gal for a difference of 35gal. Maybe it's different where you live, but 35 gallons of gas does not cost a thousand dollars or more where I live.

And if it's the difference between saving $150 in gas over five years versus thousands of dollars in repair bills(and even more in possible medical bills) if I go off the road because the stock economy tires were crap in bad conditions, I think I'm going to go with spending a little more on gas every day of the week and twice on Sundays.


BTW, a 215/65-17 tire would be 5% larger than the stock 195/50-19 and 7% larger than the stock 17"(almost 2 full inches taller). Bet money all that extra mass would almost completely cancel out any RR gains.

 

My comment isn't on tire quality, but is about sidewall depth and circumference.

The stock wheel circumference may indicate that much larger tires will be a functional problem.

We know that decreased sidewall depth isn't the cause of Strawmochi's complaint because he didn't do that; he increased sidewall depth. We also know that trusting Toyota's judgement isn't the cause of his problem since he moved from stock 19 inch tires to a 17 inch tire Toyota doesn't provide stock.

My experience with CrossClimates disclosed no peculiar ride problems in warm weather, but the formula for that tire could have changed.

 

What 195/65-17? No such tire exists.

 

Correct. The CC family is not a winter tire. It's an all-weather tire. It gives you about 90-95% of the performance of an all-season tire in the spring/summer/fall and about 90% of the performance of a dedicated snow tire in the winter. It's the perfect choice for a driver that occasionally needs snow/ice performance(say they live in a temperate valley but sometimes drive into the mountains for skiing) or they need good(but not great) winter performance every year but don't put on enough miles to justify two sets of tires.

 

I was just throwing that out there to make the point that there's other tire sizes to learn about and Toyota doesn't know jack about what the best tire is for each specific customer's needs.

Clearly my recommendation was to use 215/65R17 Low Rolling Resistance (LRR) tires and I confirmed before I posted that recommendation that they're readily available from many manufacturers.

 

Strawmochi isn't complaining about a Toyota supplied tire.

 

I bought them when because I hate hydroplaning and trying to predict when it will stay warm or cold in my region.

My two gripes were a high pitched whine they produced and the set not making it to 20,000 miles. I do like lateral Gs, but that's much less durability than I anticipated.

 

So somebody goes with a two inch smaller diameter wheel and you're really going to argue the sidewall height increased? It's a two inch smaller wheel and that means there's way less tire to cushion the bumps and potholes in the road. It's absurd to say that a slight increase in sidewall height is going to compensate for two inches less diameter of the wheel.

More to the point, PriusChat and Prius owners have historically been frugal folks and we've spent decades on here discussing which tires and wheels get the very best MPG...

But now because Gen5 doesn't look ugly and costs a fortune we have this forum of wealthy people who are not frugal, not like historic Prius owners at all. I've never seen any substantive discussion in the Gen5 forum about max mpg options because the owners of Gen5 are too affluent to care about how much gas costs and in 4-5 years when gen5 owners spend another fortune on the next over-priced brand new car regular frugal Prius owners will finally start buying used Gen5 for cheap and we can finally have an intelligent discussion about high mpg tires instead of all this nonsense.

 

Lol... Way to conflate one persons post with someone else's. Why so petty about the discussion? Seriously, Gen5 owners are so presumptuous and rude.

 

Meanwhile I've been on here for 12 years talking about how I'm pumping inexpensive LRR tires up to mid-40's in PSI and getting 60K miles out of the tread.

Did you ever consider that you're getting scammed out of your tires lifespan because the tire store can tell you're wealthy enough and gullible enough to buy whatever is most profitable to them? That's what it seems like to me!

 

It is likely the aftermarket tires. With the Prius, I wouldn’t stray from the OEM low rolling resistance (LRR) tires.

I rode a 2021 Prius Limited Uber a few days ago, and the road noise was unbearable. I am guessing the aftermarket tires were the problem.

 

What are you talking about?

Yes, the wheel diameter is 2 inches smaller in diameter, but the overall diameter/circumference of the tire stays the same (or very close) because you mount tires with taller sidewalls to compensate for the loss of wheel diameter. Therefore, there is no smaller tire falling into potholes and road imperfections.

OP, many find new tires with fresh tread has a harsher ride, even when mounting the same manufacturer and model tire. The extra tread is heavier and stiffer than the old worn tire. Perhaps your ride will improve when your new tires have worn in a bit.