Tire Weight Data: RFs vs. Non-RFs

[HomeIn2]

Upon taking delivery of my 2018 X5 xDrive35i I quickly replaced my factory equipped 21” Run-Flats with non Run-Flat tires. I was curious about the possible weight reduction associated with non Run-Flats so I decided to conduct official weigh-ins.

My X5 came equipped with 21” DUNLOP SP SPORT MAXX DSST Run-Flat performance summer tires. Fronts weigh 42.0 lbs. each; rears weigh 47.8 lbs. each. Total tire weight = 179.6 lbs.

My replacement tires are factory size 21” MICHELIN PILOT SUPER SPORT non Run-Flat performance summer tires. Fronts weigh 29.5 lbs. each; rears weigh 33.0 lbs. each. Total tire weight = 125 lbs.

Total tire weight reduction achieved from switching to non Run-Flats = 54.6 lbs. However…

I also added a 19” space saver emergency spare kit (19” because I’m running MPBK) that added back 50.6 lbs.

Overall, for me the move to non Run-Flat tires AND a spare tire kit had neutral impact on total vehicle weight and tire costs. Then, factoring in a smoother ride, less road noise, better traction, and improved MPG, the switch to non-Run Flats was a no brainer.

[Wavy]

When I switched to 24s I can barely feel a difference in stiffness compared to my RF 21s.

[X5M50D]

I definitely notice an improvement with mpg - I have the winter non RFT and summer RFT and the winters add up to 10% better mpg.
Weight is certainly one reason for this!

[P1]

I did this exercise also. Non-RFT are a no-brainer.

[rhite95]

Originally Posted by HomeIn2

Upon taking delivery of my 2018 X5 xDrive35i I quickly replaced my factory equipped 21” Run-Flats with non Run-Flat tires. I was curious about the possible weight reduction associated with non Run-Flats so I decided to conduct official weigh-ins.

My X5 came equipped with 21” DUNLOP SP SPORT MAXX DSST Run-Flat performance summer tires. Fronts weigh 42.0 lbs. each; rears weigh 47.8 lbs. each. Total tire weight = 179.6 lbs.

My replacement tires are factory size 21” MICHELIN PILOT SUPER SPORT non Run-Flat performance summer tires. Fronts weigh 29.5 lbs. each; rears weigh 33.0 lbs. each. Total tire weight = 125 lbs.

Total tire weight reduction achieved from switching to non Run-Flats = 54.6 lbs. However…

I also added a 19” space saver emergency spare kit (19” because I’m running MPBK) that added back 50.6 lbs.

Overall, for me the move to non Run-Flat tires AND a spare tire kit had neutral impact on total vehicle weight and tire costs. Then, factoring in a smoother ride, less road noise, better traction, and improved MPG, the switch to non-Run Flats was a no brainer.

I just ordered these tires also. I have the Pirelli P ZERO's and it Tramlines bad. Did yours do that with the Dunlop's? I really hope this fixes it.

[Bodie217]

Originally Posted by HomeIn2

Total tire weight reduction achieved from switching to non Run-Flats = 54.6 lbs. However…

I also added a 19” space saver emergency spare kit (19” because I’m running MPBK) that added back 50.6 lbs.

There is no "however" needed. You're neglecting the fact that you removed 54lbs of unsprung weight. You adding the 50lb spare tire doesn't totally negate the advantages of the lighter wheels and tires. You have less rotating mass/inertia to overcome while accelerating.

[Sedoy]

True, if i remember correctly unsprung/sprung weight ratio is 1 to 5, so removing 1 lbs of unsprung weight is equals to removing 5 lbs of sprung weight. I would invest into light wheels/tires first before any other performance mods (except maybe a good ECU tune ).

Originally Posted by Bodie217

There is no "however" needed. You're neglecting the fact that you removed 54lbs of unsprung weight. You adding the 50lb spare tire doesn't totally negate the advantages of the lighter wheels and tires. You have less rotating mass/inertia to overcome while accelerating.

[HomeIn2]

Originally Posted by rhite95

I just ordered these tires also. I have the Pirelli P ZERO's and it Tramlines bad. Did yours do that with the Dunlop's? I really hope this fixes it.

Sorry, I never got a chance to test out the Dunlops. Upon talking delivery of my new X5, the first place I drove to was my Costco Tire Center to remove them.

[DuSh]

There's a descent amount of rotational weight that can be shed off going from RFT to non RFT. Also, forged 20'' rims can shed yet another chunk of rotational weight. It will be noticeable during acceleration and braking (and a bit better mpg)