08-25-2014, 07:51 PM | #2 |
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If there was a non-RFT option for the 21" wheels, you might be able to offset the ride quality penalty with these larger diameter wheels and lower profile tires. Don't believe there is a tire like that on the market, so yes, expect a firmer ride. Cornering will be improved at least.
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08-25-2014, 09:23 PM | #4 |
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I posted this in another thread from someone that summed it pretty well:
"Apart from styling, the pros and cons for big diameter rim low profile tires are as Greg said:- Pros Improved steering feel Improved steering response Lower rolling resistance Improved sidewall stability under braking Room for bigger brakes Less camber distortion when cornering. Cons Less progressive breakaway More susceptable to sidewall damage Heavier More expensive I would add More susceptable to tram tracking Greater steering accuracy Harsher ride More critical to tyre pressure"
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08-25-2014, 10:07 PM | #5 | |
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There are Non-RFT tires available for 21". As far as the weight, it depends on what brand and quality. If you are getting an aftermarket forged wheel, they are most likely to be lighter than the OEM or reps with the same size. But, most of the pros and cons that opasha has mentioned are correct.
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08-26-2014, 09:03 AM | #6 | |
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08-26-2014, 11:34 AM | #7 | ||
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It rides better than the 20" with RFT.
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08-26-2014, 03:20 PM | #9 |
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36-38 front, 42-44 rear - give or take, check your manual also on page 212 or so. For a smoother ride, go with the 36 and 42 because you don't want it to be too stiff of a ride as air expands with heat, and the values on the side of your door are MAX psi.
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08-26-2014, 03:28 PM | #10 |
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I bumped up 2-3 psi over suggested tire pressure on the door sticker.
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08-26-2014, 07:19 PM | #12 |
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You're most welcome, my friend .
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08-26-2014, 09:11 PM | #13 |
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That would be awesome. Any idea which non-RFT tires come in 285/35/21 and 325/30/21? Striking out on my usual sites.
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08-26-2014, 09:25 PM | #14 | |
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I couldn't find the rear non-RFT tires. My mistake.
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08-27-2014, 01:19 AM | #15 |
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Well my F10 M5 rides just as well on the 20s as my X5 rides on 19s. And those are lower profile tires on the M5 so i'd say on the X5 20" or 21" will ride just fine. Not for winter though! Smaller wheel/bigger tire is always best for snow.
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11-15-2015, 06:50 AM | #16 |
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Sorry to bump an old thread. I have been trying to find the correct tire pressures for the M Performance wheels all day and finally found this thread (For the 599M to be precise).
Thanks for the recommendation - I'll give the 36/42 combination a try as I'd prefer a more comfortable ride, and as mentioned, they will heat up and increase in pressure anyway. I've actually been running 40 F/R since Saturday as I was unsure. Keen to see the difference. I wonder though, why are the pressures different for front and rear? Also, obviously since this thread we have Michelin Pilot Sports as a non RFT option for the 21" wheels. I've got them in place of the supplied Pirellis. So far I'd say they are a significant improvement over the stock Contis on the 20" M Sport wheels let alone the Pirellis. |
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11-15-2015, 04:14 PM | #17 |
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Woah, old thread indeed! I've been running PSS on 21s since May, thank you X5M I'm about to go back to 469Ms with winter rubber (and RFT). Different pressure front and rear is quite normal, in fact, a car that has the same pressures all around would be the outlier. I run 36/44 per the manual..I believe cars with a 3rd row are recommended to tweak that slightly.
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11-15-2015, 06:03 PM | #19 |
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That is for the 21" wheels.
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11-15-2015, 07:08 PM | #21 |
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Funnily enough, just checked my own plaque and it shows 20" and 21" details.
However it actually states: 20" Max 3 persons F240 (34psi) / R240 (34psi) 21" Max 3 persons F250 (36psi) / R250 (36psi) 20" and 21" Max 5 persons + luggage F270 (39psi) / R320 (46psi) The interesting thing is that unless you have a full load, the recommend the same front and rear. |
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