Last year I did a last minute HPDE at Portland International Raceway in my 2016 R manual. I had a set of use Audi 8 x 17 wheels and used those with a set of 240 tires. Had a lot of fun and decided I'd do it again this year. With more time to prepare I bought a set of Konig 8.5 x 17 wheels to use with the same tires. The weight difference between the Audi and Konig is 11 lbs per wheel (with Konig being lighter). I assume this will make a performance difference, but have limited experience with how much. Any insights?
7
Performance impact of lighter wheels?
- Thread starter Crossle32
- Start date
DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
Closest thing to that test would be this that GRM did:
https://grassrootsmotorsports.com/forum/grm/are-lighter-wheels-really-bett/138614/page1/
There were some measurable differences, but it's also on a ~100hp 2000lb Miata with 12lb/corner change.
Sheer wild guess I'd say *maybe* a second around at 1:20-1:40 lap road course could be attributed to the wheels (if you were to take a consistent and competent driver do an A/B/A test).
I'm assuming that was your first HPDE if I'm reading between the lines correctly?
Realistically almost all improvements will come from driver development more than anything, especially in your first dozen + events. Until you can drive consistently lap after lap and you're actually getting 95%+ out of the car, it'll be hard to pinpoint how much a given modification actually helps.
https://grassrootsmotorsports.com/forum/grm/are-lighter-wheels-really-bett/138614/page1/
There were some measurable differences, but it's also on a ~100hp 2000lb Miata with 12lb/corner change.
Sheer wild guess I'd say *maybe* a second around at 1:20-1:40 lap road course could be attributed to the wheels (if you were to take a consistent and competent driver do an A/B/A test).
I'm assuming that was your first HPDE if I'm reading between the lines correctly?
Realistically almost all improvements will come from driver development more than anything, especially in your first dozen + events. Until you can drive consistently lap after lap and you're actually getting 95%+ out of the car, it'll be hard to pinpoint how much a given modification actually helps.
GoatAutomotive
Autocross Champion
- Location
- Georgetown, TX
- Car(s)
- 2017 VW GTI SE, DSG
From experience:
Your braking distances will improve
Your steering will feel lighter and livelier
Your acceleration will feel snappier
Your car will love you more.
OE VAG wheels are like steel-toed work boots: strong-ish but HEAVY and not suited for speed work.
You’re gonna love the new setup.
I’ve gone from 26lbs wheels down to 19lb + lighter wider tires on 2 different platforms, and it was always an improvement in comfort, suspension and steering response, acceleration and braking.
Lemme know if this helps.
Your braking distances will improve
Your steering will feel lighter and livelier
Your acceleration will feel snappier
Your car will love you more.
OE VAG wheels are like steel-toed work boots: strong-ish but HEAVY and not suited for speed work.
You’re gonna love the new setup.
I’ve gone from 26lbs wheels down to 19lb + lighter wider tires on 2 different platforms, and it was always an improvement in comfort, suspension and steering response, acceleration and braking.
Lemme know if this helps.
GoatAutomotive
Autocross Champion
- Location
- Georgetown, TX
- Car(s)
- 2017 VW GTI SE, DSG
That IS and will be a dramatic delta (change). That's a solid 40% drop in rotating mass.
Double down: make sure you pick out tires that aren't a drastic increase in weight.
Bridgestones, Firestones, Toyos and Yokohamas, for example, can be quite heavy due to the stiffer, reinforced sidewalls.
Continentals and Michelins tend to be lighter. All rated sized being equal.
All of the tire weights are neatly documented on TireRack's website, so you can see that none of this is conjecture.
DerHase
Autocross Champion
- Location
- Hampton Roads, VA
- Car(s)
- 2019 GTI Rabbit
That IS and will be a dramatic delta (change). That's a solid 40% drop in rotating mass.
Double down: make sure you pick out tires that aren't a drastic increase in weight.
Bridgestones, Firestones, Toyos and Yokohamas, for example, can be quite heavy due to the stiffer, reinforced sidewalls.
Continentals and Michelins tend to be lighter. All rated sized being equal.
All of the tire weights are neatly documented on TireRack's website, so you can see that none of this is conjecture.
Just to piggyback on this: don't buy tires strictly because of weight.
It definitely does have an effect on NVH especially over bumps, but ALWAYS buy based on the compound you need if it's for anything even remotely considered performance driving.
Otherwise some kind of Michelin Eco-BS tires would be the ones to have.
SouthFL_Mk7.5
Autocross Champion
- Location
- South Florida
- Car(s)
- 2019 GTI S
We’ve run the same autox course on 18” Austins and on 17” Assetto Gara. The firm sidewall of the 225/45 RT660 on the 17” wheels feel as responsive as the Austins on 225/40 PZero with all the benefit of the weight savings.
The Austins make the car feel more stable and planted while the Assetto Gara make the car feel more dynamic. We run better times with the Assetto Gara but that’s mostly tire related.
The Austins make the car feel more stable and planted while the Assetto Gara make the car feel more dynamic. We run better times with the Assetto Gara but that’s mostly tire related.
SouthFL_Mk7.5
Autocross Champion
- Location
- South Florida
- Car(s)
- 2019 GTI S
Today we were swapping out the 17” RT660 and putting the 18” PZero back on and I went for a drive with the 17” Sparco wheels on the driver’s side and the 18” Factory wheels on the passenger side.
I could feel the difference in the lateral transitions and they were exactly as I had described them in the paragraph quoted above. Austins felt more stable and planted, Assetto Gara were more dynamic. Again, tires/ sidewalls are the major factor but the weight difference is also perceived.