E46 M3 19" driving compromise

[youdsy]

Hi All,

recently changed the standed 18" m3 alloys for a set of genuine 19" CSL set. The resaon i decided to change from the 18's to the 19's was purely from a visual point of view and i must admit that the car looks alot better than before. However, the cars handling has become alot worse than it use to be and im finding that the car is alot more unstable at high speeds whilst traveling along B roads! I always knew that that the 19's would compromise the handling as the car drove surperb with the 18's on but i didnt realise it would be that much of a compromise! Is this the case or could it just be something wrong with my car's handling/setup? recently checked the tyre pressures and all seemed to be fine so i cant put the blame down to the tyres ( 32 psi fronts and 34 psi at the rears)

Any advice/comments would be grateful

thanks

[shim]

the difference between 18 and 19 is minimal and certainly NOT the cause of your problems

what make tyres were/are they?

[mmm-five]

The difference was enough for me to get rid of my CSLs (bought with the car from BMW) and go back to standard 18's - on a Z4MC.

That 1/2 inch extra sidewall each side of the rim seemed to sort it for me.

[shim]

there are so many factors like tyre choice, wheel weight and geo

18s never felt that much difference to me and cetainly didnt improve laptimes

[gareth h]

18"s to 19"s does make a big difference on less than perfect road surfaces, I've just gone from CSLs back to 18"s there is much less tramlining and you're not constantly having to make steering inputs to stay online.
On the road at least I'm afraid it really is a case on 19"s for show 18"s for go, I believe this was also the conclusion from most of the roadtesters when the M3 was released.

[motors]

shim said:

the difference between 18 and 19 is minimal and certainly NOT the cause of your problems

what make tyres were/are they?

I agree with Shim, also why would bmw put 19's on the csl if the handling was going to be compromised

[shim]

motors said:

shim said:

the difference between 18 and 19 is minimal and certainly NOT the cause of your problems

what make tyres were/are they?

I agree with Shim, also why would bmw put 19's on the csl if the handling was going to be compromised

yep they are all cunningly not talking about geo or tyre choice..........

road use there isa feeling of greater forgiveness on the bumps due to the flex you get in the tyre but a little driving skill can compromis for this minor shortfall

i dont see any Ring times beating the 7.50 for the CSL on 18 inch rims and tyres alone, do you?

[gareth h]

I am talking about the same geo and tyres (and spacers on the front of the 18"s to give similar offset to the CSL rims, although my car is running on KW V3) , I haven't been to the ring but would assume the surface is in better condition than the rural roads of Wiltshire where I drive, I'm sorry on these roads it is absolute fact 18" rims work better than 19"s.

[outnumbered]

Tyre size & manufacturer makes a big difference too. I don't notice a huge difference between my car on standard size tyred 18s (225/45 + 255/40) or 19s (225/40 + 255/35), both with PS2s. There is some difference, but hardly night and day.

However, I used to have Contisports on the 19s in 235/35 and 265/30 and I found that was much more prone to tramlining and threw you around a bit more on B roads.

[youdsy]

the tyres in question are mitchelin pilot sports 225/40/19 at the front and 255/35/19 at the rear. Just crossed my mind whilst writing this that the CSL alloys are wider than the standard m3 Alloys, think the fronts may be .5" wider. Should i be running 235/40/19 and 265/35/19 instead of the standard setup? Only really noticable when on B roads,cant say that i notice a huge difference whilst on motorways! Also are the Pilot Sports any good or should i opted for the PS2's instead when i come to replace them?

Edited by youdsy on Friday 1st January 20:57