Switching back to 17" Wheels from 18" for acceleration feel? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

bobsacamenoh · 08-30-2014, 01:58 AM

Anyone do this switch? I recently switched from the stock wheels to an 18 x 8.0 wheel with 225/40/18 Pilot Super Sports. The grip is awesome, but the acceleration "feel" is noticeably less quick. The 18"s have only been on for a day and already thinking of switching to a lighter weight 17. Should I just wait out the adaptation period for my senses to get used to it? How long did it take you to get used to the feel or did you never get used to it and just switched back?

Thanks

br@ndon · 08-30-2014, 02:35 AM

Did you get an alignment?

bobsacamenoh · 08-30-2014, 02:43 AM

Quote:

Originally Posted by br@ndon

Did you get an alignment?

Not yet. Was waiting for my coil overs to be installed before doing that. Should I get the alignment now or just wait? Might be a couple more weeks until I get the coil overs on. Sorry, I'm a noob to all this.

N1rve · 08-30-2014, 02:51 AM

Are the 18 inch wheels heavier than the stock 17s? It could just be the extra weight from the wheels.

bobsacamenoh · 08-30-2014, 03:03 AM

Quote:

Originally Posted by N1rve

Are the 18 inch wheels heavier than the stock 17s? It could just be the extra weight from the wheels.

The wheels are about 0.25lbs heavier. Not sure about the wheel + tire weight vs. stock tho.

abraxis · 08-30-2014, 03:59 AM

Even if you kept the weight the same, it would still feel slower going to 18s. You've moved the mass further out.

skyloran · 08-30-2014, 03:23 PM

alignment will help.

stonenewt · 08-30-2014, 03:30 PM

My BMW seemed to accelerate slower on PSS than Efficient Grip Performance. This is at odds with a g meeter says that the PSS are oh-so-slightly faster in 1st & 2nd. Just saying.

dradernh · 08-30-2014, 04:21 PM

Quote:

Originally Posted by br@ndon

Did you get an alignment?

Quote:

Originally Posted by skyloran

alignment will help.

Why will this help?

pantdino · 08-30-2014, 04:33 PM

Quote:

Originally Posted by bobsacamenoh

Anyone do this switch? I recently switched from the stock wheels to an 18 x 8.0 wheel with 225/40/18 Pilot Super Sports. The grip is awesome, but the acceleration "feel" is noticeably less quick. The 18"s have only been on for a day and already thinking of switching to a lighter weight 17. Should I just wait out the adaptation period for my senses to get used to it? How long did it take you to get used to the feel or did you never get used to it and just switched back?

Thanks

I have never read anywhere that the weight difference with a +1 change will make a noticeable difference in acceleration or throttle response, despite the increased angular momentum from having more weight further from the axle .

Increased unsprung weight and shorter sidewalls will give you a harsher, possibly less well controlled ride

Wayno · 08-30-2014, 07:30 PM

Why are people talking about alignments for straight line acceleration, when no suspension has been changed!!

The stock 17's are super heavy pieces of shit. 18's that are even heavier have more weight further away from the wheel center as abraxis stated. Further, both the 16 and 17" oem tires have fairly light sidewalls, so wider tires put even more weight away from the wheel center.

As far as I know even if you have a BBK you don't need 18's except for looks.
Looks =/= performance.

It's good that you noticed immediately that the car is sensitive to rotating mass. The oem suspension is sensitive to unsprung mass too. You have more tire grip which you noticed but likely have less mechanical grip right now. It works better the lower weight your wheels and tires are. That won't matter when you switch to stiff coils though.

stugray · 08-30-2014, 07:35 PM

If you increase from 17 to 18" tires and keep the same tire aspect ratio, then the circumference of the tire will increase.

A larger tire circumference will mean less available torque at the contact patch than before.
This would result in lower acceleration.

What size tire did you have before and what size tire after?

08-30-2014, 01:58 AM	#1
bobsacamenoh Senior Member Join Date: Apr 2014 Drives: 2014 Scion FRS Location: US Posts: 148 Thanks: 52 Thanked 68 Times in 22 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Switching back to 17" Wheels from 18" for acceleration feel? Anyone do this switch? I recently switched from the stock wheels to an 18 x 8.0 wheel with 225/40/18 Pilot Super Sports. The grip is awesome, but the acceleration "feel" is noticeably less quick. The 18"s have only been on for a day and already thinking of switching to a lighter weight 17. Should I just wait out the adaptation period for my senses to get used to it? How long did it take you to get used to the feel or did you never get used to it and just switched back? Thanks

08-30-2014, 02:51 AM	#4
N1rve Senior Member Join Date: Oct 2013 Drives: 2019 BMW ///M4 Location: Los Angeles, CA Posts: 2,332 Thanks: 102 Thanked 1,167 Times in 714 Posts Mentioned: 28 Post(s) Tagged: 0 Thread(s)	Are the 18 inch wheels heavier than the stock 17s? It could just be the extra weight from the wheels. __________________ N1rve 2019 BMW ///M4 - Alpine White \| Sakhir Orange/Black Leather \| M-DCT \| Executive Package \| 19" Black 437M Wheels \| Carbon Fiber Trim \| Sunroof \| Active Blind Spot \| Heated Steering Wheel \| Adaptive M Suspension

08-30-2014, 03:23 PM	#7
skyloran Honeydew old ID Join Date: May 2014 Drives: GT86 Location: California Posts: 222 Thanks: 7 Thanked 43 Times in 33 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	alignment will help. __________________ Used to owned M3 and Lotus, but love my GT86 the most.

08-30-2014, 07:30 PM	#11
Wayno Senior Member Join Date: Apr 2014 Drives: Toyota 86 GTS Location: Australia Posts: 1,129 Thanks: 453 Thanked 895 Times in 424 Posts Mentioned: 211 Post(s) Tagged: 0 Thread(s)	Why are people talking about alignments for straight line acceleration, when no suspension has been changed!! The stock 17's are super heavy pieces of shit. 18's that are even heavier have more weight further away from the wheel center as abraxis stated. Further, both the 16 and 17" oem tires have fairly light sidewalls, so wider tires put even more weight away from the wheel center. As far as I know even if you have a BBK you don't need 18's except for looks. Looks =/= performance. It's good that you noticed immediately that the car is sensitive to rotating mass. The oem suspension is sensitive to unsprung mass too. You have more tire grip which you noticed but likely have less mechanical grip right now. It works better the lower weight your wheels and tires are. That won't matter when you switch to stiff coils though. __________________ rom downloads, information and examples Toyota 86 GTS OFT - Guide To Dialling In OTS Base Tune OFT - Example Alternate Maps for AT, 98RON, E85, MAF Scales

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08-30-2014, 02:35 AM	#2
br@ndon Member Join Date: Feb 2014 Drives: 2014 Monogram FR-S Location: Long Beach, CA Posts: 92 Thanks: 4 Thanked 28 Times in 16 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Did you get an alignment?

08-30-2014, 03:59 AM	#6
abraxis Senior Member Join Date: Aug 2014 Drives: many Location: here Posts: 487 Thanks: 190 Thanked 279 Times in 152 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	Even if you kept the weight the same, it would still feel slower going to 18s. You've moved the mass further out.

08-30-2014, 03:30 PM	#8
stonenewt Senior Member Join Date: Aug 2014 Drives: BMW 120d Location: England Posts: 237 Thanks: 29 Thanked 65 Times in 47 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s)	My BMW seemed to accelerate slower on PSS than Efficient Grip Performance. This is at odds with a g meeter says that the PSS are oh-so-slightly faster in 1st & 2nd. Just saying.

08-30-2014, 07:35 PM	#12
stugray Banned Join Date: Sep 2013 Drives: 2013 GBS BRZ Limited Location: Colorado Posts: 1,925 Thanks: 627 Thanked 1,445 Times in 711 Posts Mentioned: 41 Post(s) Tagged: 0 Thread(s)	If you increase from 17 to 18" tires and keep the same tire aspect ratio, then the circumference of the tire will increase. A larger tire circumference will mean less available torque at the contact patch than before. This would result in lower acceleration. What size tire did you have before and what size tire after?

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