Pilot Sport 5

[Sam86]

I recently went from a 225/45/17 set of Pilot Sport 4 tyres on 17x7.5 wheels to 235/40/18 Pilot Sport 5 tyres on a 18x8 set of wheels. (For some reason the PS5 tyres were several $100 cheaper than the standard PS4 tyres of the same size?)

I was fully expecting my car to feel slower but have more grip due to increased wheel weight/ rolling diameter. I don’t know whether I had a faulty set of PS4 tyres but these PS5 tyres have dramatically increased my acceleration all around.

I’m NA, mostly full bolt on with E85. On the PS4 tyres I felt confident around corners but didn’t notice any change in acceleration compared to my crappy 215, random brand tyres. Off the line it never felt slow but was a little sluggish to get going.

But yea, PS5 tyres on 18x8, significantly faster feeling of acceleration off the line, something I fully wasn’t expecting and am very pleased about. I don’t think it’s placebo at all. Even 3rd gear at 3K rpm it felt like sudden acceleration where as on the PS4’s, anything under 4-5K in 3rd was slow

(Just want to add I haven’t done anything else performance wise or suspension wise between changing to the larger wheel and PS5 tyres. Both wheels were not forged or advertised as lightweight wheels, and I was driving on the same roads I had been on days prior on my PS4 tyres.
Next step is lowering the car…

Actually feels like i’m on E85 now

[mike2100]

Nice looking wheels, what are they?
Even if neither wheel is forged or advertised as light weight, there can be significant weight differences between them. Peruse the tire rack website, which lists the weight for most of the wheels they sell. Similar looking wheels in similar sizes from different manufacturers can differ by as much as 10 lbs in weight!

[gen3v8]

It certainly is not the diameter because the 235/40/18s are bigger. Even more so against worn 225/45/17s.

[Sam86]

Originally Posted by gen3v8

It certainly is not the diameter because the 235/40/18s are bigger. Even more so against worn 225/45/17s.

My 225 Pilot Sport 4 tyres had only been on my car for a couple 1000kms and had plenty of tread left. Even so, the difference from going to generic, worn 215/45/17 tyres that had no grip- to my brand new 225/45 pilot sport 4 tyres was not significant at all in terms of acceleration speed, only in cornering grip did I notice a difference.

The 235 40 pilot sport 5s have been an immediate and very noticeable increase in performance all around and not one I would expect. From going to a wider and heavier wheel

[Sam86]

Originally Posted by mike2100

Nice looking wheels, what are they?
Even if neither wheel is forged or advertised as light weight, there can be significant weight differences between them. Peruse the tire rack website, which lists the weight for most of the wheels they sell. Similar looking wheels in similar sizes from different manufacturers can differ by as much as 10 lbs in weight!

They’re a brand called Romac, I had never heard of them but I really like that wheel style but couldn’t find anything similar locally. The Fitment is also extremely good, front is in line with the fender, rear could use a 15-20mm spacer if you want it as aggressive as the front

I believe my 17” wheels were around 9.5kg (20.1lbs) whilst my new 18” wheels are 10.2kg (22.5lbs)

[Decep]

I think you are on the right track with the placebo effect.

[Sam86]

Originally Posted by Decep

I think you are on the right track with the placebo effect.

I really don’t think it is based on the fact I daily drive the car on mostly the same roads, similar conditions and have that expectation of how it’ll perform. I have recorded a few 0-100 times on my old wheels and will hopefully get an opportunity to time some on these tyres to compare.

That being said I still recommend the PS5’s considering the scenario that it’s placebo that at the very least they’re comparable to PS4’s on a smaller wheel. Especially as the PS5’s are advertised as wearing less over time than the standard PS4

[Decep]

I don't know what to tell you besides it sounds ridiculous that you think you feel a 30+ whp gain from changing your wheels and tires.

[churchx]

It might be also some factors coinciding in same time frame. For example - maybe after tire switch he also switched to better quality fuel? Or did yearly maintenance and had fresh oil/new airfilter installed. While sizewise circumference of 18" tires in this case are slightly smaller then 17" they replaced, difference is just 2.25%, not sure if such gearing ratio chance can be felt.

[Jdmjunkie]

Maybe it feels faster because it is hooking up better, as apposed to spinning the tires?

[Tatsu333]

The only reason there would be a performance improvement (presuming you weren't struggling for traction on the 17's) is if the overall weight of the 18" wheel / tire combo is lighter, thus reducing unsprung weight. It's physics, not magic...LOL.

That said, there could also be significant placebo effect. We all are prone to some confirmation bias that allows us to find other reasons why mods may be good ideas aside from "I like them", and that's totally cool - just enjoy it!

[Sam86]

Originally Posted by Tatsu333

The only reason there would be a performance improvement (presuming you weren't struggling for traction on the 17's) is if the overall weight of the 18" wheel / tire combo is lighter, thus reducing unsprung weight. It's physics, not magic...LOL.

That said, there could also be significant placebo effect. We all are prone to some confirmation bias that allows us to find other reasons why mods may be good ideas aside from "I like them", and that's totally cool - just enjoy it!

I get what you’re saying but I was completely prepared to be experiencing slower speeds due to the increased wheel size and would have been fine with it as I plan to boost in the near future.

I’m accelerating the same way I always have yet I’m feeling myself being pushed back into my seat more from the torque. Something I wouldn’t expect to feel if the performance after the change was worse or equal as you’d be accustomed to the sensation. The first few drives a day after install I would describe as when you’re sitting in the passenger seat letting someone else drive your car in terms of how the torque felt

I’m not sponsored my Michelin… had I felt worse performance or no noticeable change I would never have made this thread. I made it because I went to do my groceries the day after install, driving the car the same way as I always had and noticed an immediate difference in the way it responded to even slight throttle acceleration and am extremely surprised by it

Originally Posted by churchx

It might be also some factors coinciding in same time frame. For example - maybe after tire switch he also switched to better quality fuel? Or did yearly maintenance and had fresh oil/new airfilter installed. While sizewise circumference of 18" tires in this case are slightly smaller then 17" they replaced, difference is just 2.25%, not sure if such gearing ratio chance can be felt.

I was still on the same tank of fuel and had done no maintenance or changes. I drove back from the shop which was only about 3kms away, then took the car out about 3 hours later, not even intending to “test” the wheels, just going about my day and immediately noticed I was going well over the speed limit on accident, by accelerating with the roughly the same amount of throttle pressure as I always had when I’m just daily driving

[Tatsu333]

Originally Posted by churchx

It might be also some factors coinciding in same time frame. For example - maybe after tire switch he also switched to better quality fuel? Or did yearly maintenance and had fresh oil/new airfilter installed. While sizewise circumference of 18" tires in this case are slightly smaller then 17" they replaced, difference is just 2.25%, not sure if such gearing ratio chance can be felt.

235/40R-18 is actually taller diameter / larger circumference (at 815 revolutions per mile) vs. a 225/45R-17 (at 833 revolutions per mile).

That would present a 2.2% gearing disadvantage on the 18's, if anything.

[gen3v8]

Originally Posted by churchx

While sizewise circumference of 18" tires in this case are slightly smaller then 17" they replaced, difference is just 2.25%, not sure if such gearing ratio chance can be felt.

Doing the math the 18" tire is smaller but this calculator says otherwise. The difference is very little as you say.

https://www.willtheyfit.com/index.ph...h=8&offset2=48