Will a 35mm offset wheel work?

Try This

http://www.1010tires.com/WheelOffsetCalculator.asp

Also, I believe the OZ Chrono HT comes in the right size/offset.

 

I think you'll be fine with the slightly wider footprint. Unless you're changing the car's weight, it's pretty much going to sit the same way.

Your combined offset is only spreading your footprint by 20mm. Considering your 42/40 tire pressure makes a narrower contact patch, your contact patch with 35mm offset will have an outside edge that is pretty much identical to the OEM wheels at stock tire pressure.

Aside from that, I'm not sure it makes much difference. I just changed out our '05 to 16x7's with a 40mm offset, and put on wide 205/55 tires. Parked next to the '06 with stock wheels & tires, it's got a noticeably wider stance and contact patch... but where you've got a 20mm combined outward bump, I've got 36 out plus 16 in. My first impression is that handling has improved and alignment doesn't seem to be a noticeable problem.

 

I'd never change the wheel offset on the front, especially on a front-wheel-drive car.

It's got nothing to do with "stance".

It's got everything to do with maintaining the same steering roll radius (aka scrub radius) as the car had when it left the factory (typically a small amount of negative steering roll radius).

Change the amount of roll radius (esp. from negative to positive) from the original factory specs. and you can find your handling under heavy braking has changed quite a bit.

Here is a picture showing a small amount of positive steering roll radius (atypical):



Wheel bearings can wear in interesting ways (sometimes catastrophically) if you're one of those idiots who desperately wants that open-wheel racer look and goes for huge amounts of negative offset.

 

Man, those Motegi's look sweet! B) Nice to find a 10-lb wheel for under $220, too.

The stock Integrity's will work on a 6.5" rim, but that's their rated max -- Goodyear actually lists 5.5" as their measured width. Given the heavy front end of the Prius, I'd be worried. If I inflated to high pressure, I might blow off the rim on a hard cornering turn; if I kept pressure low, I might get a weak contact on the center tread. Given the load rating on these tires is only 1168 @ 44 PSI (which means less load at lower pressures), I already worry about exceeding load on, say, hard-braking in an evasive maneuver with a loaded car.

For integrity's, you may want to consider the P205/70R15: rim width is good to 7", measured is 6", and with a tread width of 6.1" vs the stock 6.4" your mileage might even go up.

An even better match might be the 215/70R15: measured on your 6.5" rim, same 6.4" tread width, and with the highest load rating of the bunch.

 

Hmm, interesting point: I'm a bit surprised Tirerack would recommend 185/65-15 on a 6.5"... but it is in the range.

It might not save that much money to keep the stock tires - if you find rims and tires at the same place they will probably mount & balance free, and then you could re-sell the stock set intact.

If you're really into saving weight, ditching the tire pressure sensor would help a little -- it weighs an ounce or so, requires a (heavier) metal valve stem, and must be counter-balanced... so you're adding up to 4 ounces per wheel to keep the TPM sensors. Keeping them will also cost you the $100 or so to have your tires unmounted, recover the sensors and move them to your new wheels, and re-mount.

Then there's also the issue of whether the TPM sensors will work ok in the new rims. I've seen a couple posts about Prius requiring a certain angle or something.

 

I just found a set of snow tires on Subaru wheels (5x100) but the offset is 55mm ... will this work with a Gen II Prius?

 

its a strut FE not a king pin FE
in any event similar equipment on Gen3 sees 17" wheels with 50mm offset vs the 15x6" rims with a 45mm offset, and my Gen2 spare is 125/70/17, which creates a situation where there are a range of offsets not a constant dimension or a single acceptable figure.