BMW-Driver.net Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter #1
Hi all,

I'm currently looking at a new G30 with 19-inch alloys, on 245/40/R19 runflats. Just wondering how much of a change they'd be from the 225/55/R17s on my 2012 520d SE? Specifically I'm talking grip, ride comfort, humps, bumps and potholes and fuel economy - any thoughts?
 

·
Registered
Joined
·
1,857 Posts
Not a scientific rule, but over the past few generations its been fairly safe to go up one wheel size from the basic standard wheel for that model. 15's were std on the e39 and 16's were probably the best real world size for a balance of handling and comfort. 16's were the intro wheel on the e60 and 17's probably the optimum balance. 17's std on the f10 and 18 were probably the optimum wheel there.

I think the basic 520d G30 has 17's as standard so I'd guess 18's would be the optimum wheel. Having said that, if you also added the adaptive suspension then you might get away without 19's wrecking your head and your fillings.
 

·
BMW 523i (2006MSport Kit)
Joined
·
111 Posts
Not a scientific rule, but over the past few generations its been fairly safe to go up one wheel size from the basic standard wheel for that model.....
Hi,

I would agree 100% with that. It's a real shame that BMW don't give us the maximum wheel size to suit the design of each car - for safety, optimum road holding and performance and then not least, because of the amount of money we are spending with them.

As for the old run flats, I've had a love-hate relationship with them since I got my BMW on the very first day - super idea, but far too expensive and as time has gone on, I've come to the conclusion that they can be repaired when you get a "normal" puncture in them, despite what we might be led to believe by those who sell very expensive tyres !
 

·
Registered
Joined
·
16 Posts
Discussion Starter #4
Hi,

I would agree 100% with that. It's a real shame that BMW don't give us the maximum wheel size to suit the design of each car - for safety, optimum road holding and performance and then not least, because of the amount of money we are spending with them.

As for the old run flats, I've had a love-hate relationship with them since I got my BMW on the very first day - super idea, but far too expensive and as time has gone on, I've come to the conclusion that they can be repaired when you get a "normal" puncture in them, despite what we might be led to believe by those who sell very expensive tyres !
Likewise, I had one puncture in 5 years on the runflats, and Scully's on Malahide Road fixed it for small change! On the G30 with R19 runflats, I gave the car a good test run, the salesman to his credit picked a route that had plenty of bumps, and said I could feel free to aim at them :smile: Hard to honestly say how the ride compares to my current 520 though, as I'd never driven that road before.....
 

·
BMW 523i (2006MSport Kit)
Joined
·
111 Posts
Likewise, I had one puncture in 5 years on the runflats, and Scully's on Malahide Road fixed it for small change! On the G30 with R19 runflats, I gave the car a good test run, the salesman to his credit picked a route that had plenty of bumps, and said I could feel free to aim at them :smile: Hard to honestly say how the ride compares to my current 520 though, as I'd never driven that road before.....
But I bet you've been back to drive it again since ;)
 

·
Registered
Joined
·
1,857 Posts
As for the old run flats, I've had a love-hate relationship with them since I got my BMW on the very first day
I've hated the RFT's on the e91 and had some on the Z4 for a short while and the car was horrible on them, nervous and filling rattling on an R road. To be fair, having been through a couple of sets of RFT's on the e91 (all BMW * approved tyres) they have improved but I would still consider them to require compromises I wouldn't want to make if it was my daily.

I haven't has RFT's on the e60 and more than happy with that but I did have them on the f10 (17's only) and to be honest they were absolutely fine on it. It was perfectly comfortable and handled just fine, with no obvious compromise to make.

I also have them on the 630 on 19's and they're not too bad, even at this size and profile. The occasional road blemish will sound crashy and transmit a bit of shock in to the car. Its also a little bit inclined to follow the road camber but this is more noticeable when the tracking is a little off. All in all, I'm sure it would be better on non-RFT's, but it wouldn't make me feel an unshakable need to change them.

I suspect that BMW have put a lot of effort in to improving the suspension engineering to better match the characteristics of RFT's and the e91 shows that the tyres themselves have also improved over the years.
 
1 - 7 of 7 Posts
Top