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Rhines

New g31 owner tyre setup question

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Hi everyone,

 

Just picked up a used 520d G31 xdrive. It's got staggered 19inch wheels 245 in the front and 275 on the rears. My question is, is it needed? 

I just want comfort on journeys so thinking of switching to non runflats and a square setup. Possibly pilot sports. Just wanted to add that it's an SE trim. 

Any help would be greatly appreciated. 

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Non run flats is a popular choice, the difference in comfort is subjective imo. 

 

The staggered set up is there for a reason and changing it would possibly have insurance implications, also from memory the wheels will be a different size. 

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Answer your question first, is 245 or 275 needed? No. My F10 has 225 summer and it's enough. For both my F10 and G31 with 225 tyre (regareless winter or summer tyre), as soon as I spin the rear wheel other than in snow, wife, kid, and dog will start the complain. Then, if I'm driving alone, I don't feel the 5 is encouraging me to keep pushing to the limit. It is a good handling car in its class but it's not a sport car after all. 

 

My original wheel set is 19 inch staggered comes with m sport trim. My winter wheel set is 17 inch 225/55/R17 non run flat. The difference is instantly noticeable. However, after I switch back to 19 summer run flat, I then think the 19 inch is actually not bad. Ride is certainly firmer and noise is slightly louder due to the size and run-flat but still very acceptable. Haven't noticed any big change in mpg. 

 

About the tyre switch, as your car has xdrive, I've read somewhere that the xdrive is sensitive to the tyre. The worst case is the transfer box might get damaged by the tyre and BMW will use the excuse of you are not using star mark tyre to decline the warranty claim. Not sure whether your area will see snow or ice in winter, I would go for a set of winter and wait for the summer to wear down then decide whether I switch to non run flat or not. Doing this will give two benefits: much much more secure driving experience in winter every year, and let you try the difference before switch the summer.

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Thanks both for the replies. I don't think I'll have issues with the insurance company. But I'm in the home counties so also not 100% sure how much winter tyres will help. But that's probably the route I may go. I guess I'm just worried about the slipping if I went 225s all around. If I had an M sport or another version say the 530 then the staggered may make sense but on an SE that's driven fairly non sporty. I'm just looking for quiet and refined rather than throwing it around the roundabouts!

 

As a side note, I bought the car approved used with tyre and alloy insurance and it's got two non star marked tyres on the fronts which I found interesting. 

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Its not 100% necessary, but being staggered the front rims are narrower at 8J and the rears are 9J

 

You could get away putting the same 245/40/19 tyre size on the back rims to give a square setup, but might not be ideal to go narrower on a 9J rim.

Changing to non run flats may improve the ride, but as said, is subjective. Being SE trim, I assume it does not have M Sport suspension, so I would not expect a huge difference if you change to a square setup 

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I have a G31 520s SE with staggered 19’s. It doesn’t need the 275s to tame its power but I stuck with the sizes rather then buying new wheels. I like the look of the 19’s which add presence to the SE in my opinion.

I did change from RFT to non-RFT keeping the same Goodyear Eagle F1 Aysmetric 3s which I’ve found good in all weathers. The non-RFT are definitely quieter and absorb more high frequency bumps (the sharp thumps you get on broken roads). I do notice a slight decrease in handling precision but it’s worth the trade off for my driving.

Be careful messing around with tyre sizes with an xdrive, they can be very sensitive. Make sure all 4 tyres are very close on wear rates as it can bugger your transfer case. We use xdrives in work on a square 17’ set up and they’re way less tyre wear sensitive to a larger staggered one.

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3 hours ago, Rhines said:

I bought the car approved used with tyre and alloy insurance and it's got two non star marked tyres on the fronts which I found interesting.

Personally, I will discuss this with dealer and BMW UK. Dealer used the non star tyre excuse to refuse to diagnosis and repair my F10 under warranty unless I change the tyre back to star mark first. My issue at that time was minor so didn't matter too much. However, based on some threads I read about the xdrive and tyre, it would be safer to not give them any excuse.

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2 hours ago, q96169we said:

Personally, I will discuss this with dealer and BMW UK. Dealer used the non star tyre excuse to refuse to diagnosis and repair my F10 under warranty unless I change the tyre back to star mark first. My issue at that time was minor so didn't matter too much. However, based on some threads I read about the xdrive and tyre, it would be safer to not give them any excuse.

Ive got email confirmation from the dealer that the warranty is still in tact if its determined that the tyres are the issue as that how it was sold to me. Hopefully there are no issues bu I do have a paper trail in case it gets a bit sketchy

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6 hours ago, q96169we said:

Answer your question first, is 245 or 275 needed? No. My F10 has 225 summer and it's enough. For both my F10 and G31 with 225 tyre (regareless winter or summer tyre), as soon as I spin the rear wheel other than in snow, wife, kid, and dog will start the complain. Then, if I'm driving alone, I don't feel the 5 is encouraging me to keep pushing to the limit. It is a good handling car in its class but it's not a sport car after all. 

 

My original wheel set is 19 inch staggered comes with m sport trim. My winter wheel set is 17 inch 225/55/R17 non run flat. The difference is instantly noticeable. However, after I switch back to 19 summer run flat, I then think the 19 inch is actually not bad. Ride is certainly firmer and noise is slightly louder due to the size and run-flat but still very acceptable. Haven't noticed any big change in mpg. 

 

About the tyre switch, as your car has xdrive, I've read somewhere that the xdrive is sensitive to the tyre. The worst case is the transfer box might get damaged by the tyre and BMW will use the excuse of you are not using star mark tyre to decline the warranty claim. Not sure whether your area will see snow or ice in winter, I would go for a set of winter and wait for the summer to wear down then decide whether I switch to non run flat or not. Doing this will give two benefits: much much more secure driving experience in winter every year, and let you try the difference before switch the summer.

I couldn't agree more.  Similarly I have staggered 20" setup + square 245 18" winters, both runflat.  I am considering swapping the 20s for 18s or 19s square setup with non-RFT MPS4 tyres.  One thing I would say is that my car is much more planted under heavy braking from high speed with the 20s on; could be profile, could be width, could tyre type.

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1 hour ago, Rhines said:

Ive got email confirmation from the dealer that the warranty is still in tact if its determined that the tyres are the issue as that how it was sold to me. Hopefully there are no issues bu I do have a paper trail in case it gets a bit sketchy

Just get hold of all evidence in case you need it. As said, they can use this as excuse to decline warranty claim despite the warranty is still in tact.

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On 17/05/2021 at 15:54, Rhines said:

Ive got email confirmation from the dealer that the warranty is still in tact if its determined that the tyres are the issue as that how it was sold to me. Hopefully there are no issues bu I do have a paper trail in case it gets a bit sketchy

Personally I'd want confirmation from BMW UK, if a dealer said good morning I'd look outside to check. 

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Ive just fired off an email to BMW UK just in case. Thank you. 

 

Ive also been looking at keeping the current 8.5j and 9.5j alloys and just squaring the setup on star marked non runflats or even a pair of good runflats.  Im probably going to get a set of winters for the 17s Ive purchased and make a decision come next year after trying out non runflat winter tyres. 

Edited by Rhines

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3 hours ago, Rhines said:

Ive just fired off an email to BMW UK just in case. Thank you. 

 

Ive also been looking at keeping the current 8.5j and 9.5j alloys and just squaring the setup on star marked non runflats or even a pair of good runflats.  Im probably going to get a set of winters for the 17s Ive purchased and make a decision come next year after trying out non runflat winter tyres. 

The 30mm tyre width won't have big impact (in reality) to comfort or economy (as least based on my comparison between 225 and 275). The rim size, whether it's run-flat, and which brand and model of the tyre will make much bigger difference. So, if you just want to dump the 275 with plenty life left and replace with new 245 tyre, it is kind of false economy. If the 275 tyre is reaching its end of life, then the most noticable difference of changing to 245 will be like saving £30 per tyre. 

 

This is just my own opinion though.

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275 certainly aren't needed for traction on an xdrive 520d. I have a rear drive only 530d with 225 17"s and the only time it breaks traction is during strong acceleration in the rain. Generally wider tires aren't going to help performance in the wet (which is why it's often recommended to use a narrower set for your winters) In any case, it can be solved by not driving like a maniac in the rain :)

 

The giant wheel trend of the last decade is one stemming from design rather than engineering necessity, cars have become much taller (particularly the bonnets because of pedestrian safety regulations) and it requires a larger wheel to look right.

Note that cars where such design considerations don't apply but are instead engineered to maximize traction use a fairly small diameter wheel with a relatively tall side wall compared to many road cars today.

 

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1 hour ago, q96169we said:

The 30mm tyre width won't have big impact (in reality) to comfort or economy (as least based on my comparison between 225 and 275). The rim size, whether it's run-flat, and which brand and model of the tyre will make much bigger difference. So, if you just want to dump the 275 with plenty life left and replace with new 245 tyre, it is kind of false economy. If the 275 tyre is reaching its end of life, then the most noticable difference of changing to 245 will be like saving £30 per tyre. 

 

This is just my own opinion though.

That's a very valid point. The rears have about 4.5 mm left so going to try and keep them for a while longer. I'm not going to rush into anything right now because there's no reason honestly. I'd probably like a set of 18s down the road but there's no point changing anything right now.  I have toyed with the idea of getting 2 8j 664 19 inch alloys to match the front and going square with non runflat pilot sport 4s but honestly I'm not going to rush into it. 

Edited by Rhines

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Maybe I'm missing something but why change a factory approved and delivered set up to something non-standard. The wider rears on wider rims are matched to the fronts on slightly narrower rims and changing from 275 to 245 will offer no discernible difference in comfort nor economy. Changing to non-RFTs as many have done makes sense but altering the tyre size makes none at all as there is no benefit.

Edited by Matthew Ashton

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44 minutes ago, Matthew Ashton said:

Maybe I'm missing something but why change a factory approved and delivered set up to something non-standard. The wider rears on wider rims are matched to the fronts on slightly narrower rims and changing from 275 to 245 will offer no discernible difference in comfort nor economy. Changing to non-RFTs as many have done makes sense but altering the tyre size makes none at all as there is no benefit.

That's a valid point. I guess I've just never done staggered before and on an X drive 520, I'm not putting down as much power as other cars. They're an option on the se, which normally comes with 17in non staggered tyres. 

 

I do plan on switching to non rft but figured while I'm at it, ask the question about staggered versus non staggered. I was going to say I could rotate the tyres on a non staggered alloy but just read that BMW advises against rotating tyres so that argument is moot. 

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1 hour ago, Rhines said:

That's a valid point. I guess I've just never done staggered before and on an X drive 520, I'm not putting down as much power as other cars. They're an option on the se, which normally comes with 17in non staggered tyres. 

 

I do plan on switching to non rft but figured while I'm at it, ask the question about staggered versus non staggered. I was going to say I could rotate the tyres on a non staggered alloy but just read that BMW advises against rotating tyres so that argument is moot. 

 

The amount of power a car puts down is irrelevant.  My 640i has staggered summer wheels/tyres and square winter wheels/tyres and for we mere mortals both do a fine job of handling the power and are factory fit in both cases. Yes, standard specification SE models have a  square set up but as soon as bigger wheels are specified at build time, the staggered sizing is introduced. Stick with what the factory intended for your car and just enjoy the drive in the knowledge that you will be keeping the car and its xDrive happy.  

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13 minutes ago, Matthew Ashton said:

 

The amount of power a car puts down is irrelevant.  My 640i has staggered summer wheels/tyres and square winter wheels/tyres and for we mere mortals both do a fine job of handling the power and are factory fit in both cases. Yes, standard specification SE models have a  square set up but as soon as bigger wheels are specified at build time, the staggered sizing is introduced. Stick with what the factory intended for your car and just enjoy the drive in the knowledge that you will be keeping the car and its xDrive happy.  

 

the factory intended that the car work with a number of different configurations

 

G31 SE x drive would normally come in 18in 245 squares, even if its a 3.0d . The 17 inch wheel is pretty much a base SE spec.  You can specify M sport staggered wheels for a SE, thats what I think happened in this case. No its not needed

 

There is nothing wrong with changing wheels around as long as the correct BMW specs are followed .   Winter tyres are directional , hence better grip in the wet as well as being more sticky..   Staggered summers are asymmetrical , better in the dry,  but they will aquaplane on  wet roads

 

 

 

 

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if you look at the configurator, you can still specify 19 inch wheel for a G31 520i SE.. But its a very expensive option,

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I found the grip on my 18 inch 245 square winters grand on my F10 RWD, also find them grand on my G30 but it is a 530d x drive lol so I wouldn’t expect grip issues, thou even with x drive you feel loss of grip for a second or two .. and it’s no more than the 275 tyres.

 

I changed my summers 20 inch from run flats to the pilot sport 4s non run flats and there is a improvement in ride, of course it’s not as comfortable as my 18 inch run flat winters, but better than the Goodyear AS3 run flats it’s came with from the factory.

 

 If the winter 18 inch Runflats are 10/10 the Good year 20 inch runflats where 7/10 and the pilot sport 4s non RFT are 8 -8.5/10.

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My G31 530d Xdrive ran staggered as did my old E61 as does the Alpina.

As folk on this thread point out, be very careful about *marked tyres and also the rolling diameter difference between front and rear wheels. Apparently, the X drive transfer box is quite intolerant of big discrepancies (Don’t entirely subscribe to the theory but…) hammering its clutches in way that can potentially result in a £5K+ bill for a new box.

Personally speaking, I think bigger rears suit the vehicles aesthetic and certainly contribute to both the handling and power delivery (40/60 split, rear bias on the diesel).  I did find my Premacy 3 ROFs running at slightly reduced pressures gave a great combination of supple, jolt free ride whilst maintaining stability and grip.  That said I rarely drove in anything but comfort – do you have adaptive dampers by any chance?  Run flat sidewalls are so much stiffer and consequently there is less “roll” on a slightly under inflated tyre thus ensuring the handling remains secure and sharp. 

Be aware turning the ride into a “magic carpet” by adjusting the pressures down may impact mpg.

Assuming you have tpms check in your iDrive what the recommend pressures for your tyre combo is.  When the tyres are cold set them to the lowest recommend pressure and run for a week. If happy, reduce them by another 0.2 bar, run a week and repeat. I would not advocate going less than 0.5 bar below the lowest recommended pressure though. (You might also have to reset the iDrive to stop flat tyre alerts on frosty mornings).

If you decide to try this, give due consideration to the nature of your vehicle use. Prolonged high speed motorway work or heavy load lugging requires a higher pressure for safety.  Interestingly if you look at the recommended pressures for Eco mode, they are filling rattlingly sky high! 

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11 hours ago, Old Codger said:

Interestingly if you look at the recommended pressures for Eco mode, they are filling rattlingly sky high! 

I run with ECO settings (and "adaptive") on both summers (19" staggered" and winters (18" square). I cannot detect any difference in comfort / ride but these higher settings do significantly reduce tramlining............

Edited by Mr H

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