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2010 2011 BMW 5 Series Forum F10 BMW 5-Series (F10) Forums Regional Forums UK Non Run-Flats and Tyre Pressure
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      02-07-2013, 11:14 AM   #1
Dom
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Non Run-Flats and Tyre Pressure

I took the plunge and changed over to NRFs. I stuck with the same size tyre -225/55/17 and the ride quality has improved considerably.
My question is should I stick with the pressures on the door which were obviously intended for RFs or should I make an adjustment for NRFs, and if so, what adjustment?
Cheers!
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      02-07-2013, 12:19 PM   #2
HighlandPete
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Quote:
Originally Posted by Dom View Post
I took the plunge and changed over to NRFs. I stuck with the same size tyre -225/55/17 and the ride quality has improved considerably.
My question is should I stick with the pressures on the door which were obviously intended for RFs or should I make an adjustment for NRFs, and if so, what adjustment?
Cheers!
Having run a 3-series on both and found the same pressures worked for both types. I'd start with the same door plate pressures and just tweak if necessary, to get best ride and wear balance. Some find a little more pressure gets the balance right, depends on use as well.

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      02-07-2013, 05:22 PM   #3
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Does that not cause a warranty issue should there be any suspension problems? Does it not make your car wallow more?
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      02-07-2013, 06:09 PM   #4
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Originally Posted by Stormbitch View Post
Does that not cause a warranty issue should there be any suspension problems? Does it not make your car wallow more?
Regarding the warranty, once you move from OEM fitment it can often depend on your relationship with the garage you use. Unless the tyres actually cause a failure or damage to some other part, there should be no issue anyway. The issue of BMW ES recovering/sorting a car without RFTs, due to a tyre failure could be an issue as BMW have indicated in the past, (not to me personally) they may not support in the same way. Whether that means they would send a bill for assistance, if you are on non run-flats, I don't know.

As to handling, that will obviously be changed, but to what degree will depend on the tyres chosen, wheel size and suspension fitted to the car. Also does the user want a softer feel to the car, as part of the ride quality improvement? Likely so. I understand the difference is not as marked on the latest cars as the early models, back in the early days of RFTs.

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      02-08-2013, 04:42 AM   #5
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Originally Posted by HighlandPete View Post
Regarding the warranty, once you move from OEM fitment it can often depend on your relationship with the garage you use. Unless the tyres actually cause a failure or damage to some other part, there should be no issue anyway. The issue of BMW ES recovering/sorting a car without RFTs, due to a tyre failure could be an issue as BMW have indicated in the past, (not to me personally) they may not support in the same way. Whether that means they would send a bill for assistance, if you are on non run-flats, I don't know.

As to handling, that will obviously be changed, but to what degree will depend on the tyres chosen, wheel size and suspension fitted to the car. Also does the user want a softer feel to the car, as part of the ride quality improvement? Likely so. I understand the difference is not as marked on the latest cars as the early models, back in the early days of RFTs.

HighlandPete
I'm not noticing any real difference at all in terms of handling etc, just a softer quieter ride.
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      02-25-2013, 08:20 AM   #6
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Sorry to barge in on the thread but i just joined the forum and I do not yet have the priviledge to create a new thread.
Does anyone know why BMW does not include the 245/50 R17 tyre size as an option for the F10?
I have a 528 with 18" rims and 245/45 tyres. I wish to change down to 17" due to suffering a lot of tyre damage caused by bad road conditions were i live.
The 17" rims would allow a higher profile tyre and hence better cushioning effect.
BMW lists the 225/55 R17 as the only option.
I do not want to loose the traction quality of the 245s but nobody at the local BMW dealership can inform me why the 245/50 R17 is not listed.
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      02-25-2013, 04:17 PM   #7
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Originally Posted by gedward View Post
Sorry to barge in on the thread but i just joined the forum and I do not yet have the priviledge to create a new thread.
Does anyone know why BMW does not include the 245/50 R17 tyre size as an option for the F10?
I have a 528 with 18" rims and 245/45 tyres. I wish to change down to 17" due to suffering a lot of tyre damage caused by bad road conditions were i live.
The 17" rims would allow a higher profile tyre and hence better cushioning effect.
BMW lists the 225/55 R17 as the only option.
I do not want to loose the traction quality of the 245s but nobody at the local BMW dealership can inform me why the 245/50 R17 is not listed.
BMW could have several reasons for not specifying a 245 section with the 17" rims.

Could be as simple as the tyre just doesn't work as well in that size. They will be striking a ride/handling balance for the given stock sizes and the 225/55 could be the best compromise in a run-flat, to speed rating and load index necessary in a 17" for the F10. Doesn't matter what tyres are available (or not) in alternative sizes, if it doesn't fit the criteria.

I run a 245/45 R18 summer tyre and the 225/55 R17 as winter wheels on my 535i and there isn't really a marked difference in ride quality. I sense the 17" tyre is stiffer in the sidewalls and therefore loses some of the gain you'd expect in a 17" wheel/tyre combination. Some of it could be running in cooler temperatures, but don't think it is the complete picture.

I'm not sure you'll lose too much grip if you opt for the best 225/55 R17 tyre you can source. I'm surprised how well a winter 225 section works on the 535i. BTW, in the 245/50 R17 size, there doesn't appear to be many tyres to choose from here in the UK in run-flat specification. And not to the normal BMW load/speed ratings either. Do you have a better range to choose from if you do depart from BMW sizing?

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      02-27-2013, 06:36 AM   #8
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Quote:
Originally Posted by HighlandPete View Post
BMW could have several reasons for not specifying a 245 section with the 17" rims.

Could be as simple as the tyre just doesn't work as well in that size. They will be striking a ride/handling balance for the given stock sizes and the 225/55 could be the best compromise in a run-flat, to speed rating and load index necessary in a 17" for the F10. Doesn't matter what tyres are available (or not) in alternative sizes, if it doesn't fit the criteria.

I run a 245/45 R18 summer tyre and the 225/55 R17 as winter wheels on my 535i and there isn't really a marked difference in ride quality. I sense the 17" tyre is stiffer in the sidewalls and therefore loses some of the gain you'd expect in a 17" wheel/tyre combination. Some of it could be running in cooler temperatures, but don't think it is the complete picture.

I'm not sure you'll lose too much grip if you opt for the best 225/55 R17 tyre you can source. I'm surprised how well a winter 225 section works on the 535i. BTW, in the 245/50 R17 size, there doesn't appear to be many tyres to choose from here in the UK in run-flat specification. And not to the normal BMW load/speed ratings either. Do you have a better range to choose from if you do depart from BMW sizing?

HighlandPete
Thanks a lot for the advice.
No, there doesnít appear to be a lot of choices. I havenít done my homework thoroughly yet but I knew quickly that both Bridgestone and Firestone donít have the size but Pirelli have it in non-run flat.
I am seriously considering changing to NRFT and buying a slim spare. I figure if I stick to the speed rating and load index I should be OK. I donít do any hard driving anyway. I mildly checked with the BMW dealer on that but he almost went berserk
As I said earlier, I suffered a lot of tyre damage between balloons and cuts. Four balloons when I was driving Goodyear and three cuts after I switched to Dunlop. All that within 40k km mileage. This is why I need to really get this thing sorted.
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