09-03-2020, 10:27 AM | #1 |
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increase the wall size on a F06 GC Tyre
Hi Guys
i want to move away from a runflat and the options for the OEM tyre size on the back is shocking 275 30 20 if i look at the next size 275 35 20 the option are endless, what repercussions are a potential for changing the size? car is totally standard rubbing? speedo? ride comfort increase ? has one one done this and regretted it ? regards ronan |
09-03-2020, 03:38 PM | #3 |
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I went with 255/35/20 FR and 295/30/20 RR, tires being wider increased the side wall a tiny bit, but I also have M5 rims to fit the wider tires in the back
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09-03-2020, 05:28 PM | #4 |
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09-03-2020, 05:29 PM | #5 |
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09-04-2020, 08:44 AM | #6 |
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Non run-flats will improve your ride quality 100%, its night and day difference
I couldn't believe it when others posted that swapping to non-RFTs made a major difference, but my M6 ride quality is way more comfortable than my 650 go get some pilot sports! |
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09-04-2020, 09:54 AM | #7 |
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If you don’t already know...mixing different types of tires and/or tire treads can create instability in certain circumstances and other peculiarities. If you’re only going to change the rear tires...then stick with what you have. If you want to move away from run flats...then do all 4 tires.
In regards to increasing the sidewall...do a google search for tire upsizing which will explain how to use tire sizes other than the ones recommended by the car manufacturer. You want to stay within specs of the overall tire circumference...which is how you can run 18/19/20 inch wheels/tires without any issues. There are sites like www.tirerack.com that give alternate tire sizes if you enter your vehicles info when looking for tires...you can safely select form those given tire sizes that have a higher sidewall. You’ll also need to consider the width of your wheels, too. Because as the sidewall height (aspect ratio) increases...the width of the tire needs to decrease. Again, if you go to a site like TireRack.com and enter your vehicle’s info...it will give a list of alternate tire sizes that should fit the OE wheels that came with your car.
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09-08-2020, 08:06 AM | #8 | |
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I went to 265/35/20 non-runflats out back, wanted to match the fronts I had put on earlier but that tire wasn't available in 275/35/20 and anything bigger than that would've made my speedo read low. At this size it reads only slightly high now, like 1+ mph at highway speeds. Next round I'll go to a different tire and likely do 285/30/20 out back. You can absolutely run a mix of RFT & non-RFT, and/or different brand/model tires front/rear. Yes there are slight differences in feel/handling/grip, but not enough to matter, the only noticeable difference is ride comfort, which I can confirm is muuuuch better with non-RFTs! The thing you don't want to mix is side-to-side, front/rear is standard practice unless all 4 tires magically wear out at the same time. Anyway the conventional wisdom is to stay within 3% of the stock diameter to keep from upsetting traction/stability systems, going from 30 to 35 profile is a pretty significant jump in those terms, hard not to exceed 3%. I went down a tick in width and I think the overall increase came out to about 2%. I haven't had any TCS/rubbing issues, my speedo is closer to accurate, and the ride is a whole lot better. Only issue is I think it looked a little better with the shorter sidewall, but that's a subjective opinion, not a technical concern |
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09-08-2020, 11:59 AM | #9 |
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245/40/R20 up front
275/35/R20 rear All tyres replaced at the same time for P4S from Dunlop run flats. You need to watch the front strut as this gets pretty close to the top of the tyre. On the tyre combination above it's within 5mm. I get no rubbing at all and had the tyres on nearly 2 years. No issues with traction control or abs. I'm massively impressed with the P4S they just don't seem like they'll wear out and have excellent grip, wet weather ability and durability. Downsides, kind of obvious but the car feels slower to accelerate but can still break the wheels free on spirited driving. The car feels way more vague and squidgy in corners. Speedo is out slightly, although i I've had no issues in the UK with average speed cameras, specs, gatsos all sticking to speed limit with car right on the button. In honesty it probably reads close to true speed. I'm running standard 373 rims and was expecting the tyre wall increase to reduce the crash over potholes and manhole covers. It probably does but I actually miss the firmness in the corners of the run flats. Would I do it again, probably not, although what I really want is 21 inch rims as I generally feel the wheel well looks a little too large for stock tyres and rims. I know I could lower it but in honesty I think a larger wheel suits the car. |
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09-12-2020, 08:36 AM | #10 | |
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Have to get the rim refurbished also. Big ding. Thanks for the info.. |
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10-01-2020, 06:37 AM | #11 | |
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10-01-2020, 06:40 AM | #12 |
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Gents would someone please help me if this configuration would work on 650xi 2013.. im scepitcal on ET:
Specs: Front: 20x9 ET 20 Hub bore: 74.1mm Rear: 20x10.5 ET 27 Hub bore: 74.1mm |
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10-01-2020, 06:51 AM | #13 | |
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L |
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10-01-2020, 09:21 AM | #14 | |
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Definitely run the specs you have above through the link Luftpost gave you in his reply (www.willtheyfit.com)..to the originally front & rear wheel/tire set-up originally on the car. This will reveal how much more "poke" or "inset" you will have with the new set-up vs the old set-up.
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10-02-2020, 02:50 PM | #15 | |
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As long as your in 1% you should be all good on the xdrive. Shouldn't be any issues on the rear. Upfront the difference on xdrive is the front strut which is shaped more like a tuning fork to allow the drive shaft through. All of that is way out the way of the wheel, so I'd have thought you should be all good. |
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11-03-2020, 09:06 PM | #16 | |
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Found a great deal on some wheels/tires combo: 20x8.5 ET35 - 245/40/20 F 20x10 ET40 - 295/35/20 R Michelin PSS I'm currently on OEM 20" M Sport set-up with 1.2" drop in front, RWD. No issues whatsoever, but I am afraid I might run into problems with this new set-up. I've read that fronts will fit with stock suspension. Would appreciate any suggestions. Thanks! Last edited by itzjoker; 11-04-2020 at 12:44 PM.. |
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11-19-2020, 03:35 AM | #18 |
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Sorry for the late response, I'm not on this forum that much these days.
I've taken a few pictures, my tyres are probably 50% worn but on stock 20" rims and all fits without any rubbing. The front upper control arm is the part that is of interest but at these sizes you have a good 5mm clearance and I've not had any issues at all. My car is filthy and the light isn't helping much, wheel is slightly turned but provided a measurement from rim edge to upper fender. It should give you an idea of the diameter difference and the impact of lowering springs. Last edited by elvisisdog; 11-19-2020 at 04:14 AM.. |
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