Not all rims are suitable for RFTs

[c-square]

Just wanted to share this interesting (distressing?) findings to those who do not already know...Last night I was just chit-chatting with a good friend and I mentioned that I am thinking of changing my boring BMW rims to some aftermarket rims (there are a couple that tickles my fancy) and he cautioned me that I have to be careful as not all rims are suited for RFTs. That lead me to do some digging around Mr. Google's closet and what I found seems to confirm what my friend said. Below is an extract of the article I was reading:1. Most people would know that the tyre full of air has a reasonable level of compliance acting as our first line of defence deflecting the poor road condition however things appear to be quite different with the Run Flat. By compromise, all BMW's fitted with RFT's have downgraded (softer) suspension to absorb the migration of these road shocks. Unfortunately this doesn't appear to be perfect as we are starting to notice that this shock migration appears to transmit some of these forces to the wheel rim, and actually cracking it in some cases without amazingly, any apparent harm to the tyre itself.2. EH2 rim. EH2 stands for E-xtended H-ump 2-two humps. The Run Flat tyre is only for use with the EH2 rims due to the two humps on the inside of the rim that has the functionality of keeping the tyre on the rim in the situation of a flat tyre. (Logically, air pressure is what holds a tyre and the rim in place together. No air pressure, the tyre disbands and you have a roly-poly. With Run Flat, the tyre is almost attached to the rim, which is why it is 100% safe in a blow-out.)Premised on the above, it appears that for safety reasons, we (ie those running on RFTs) should not simply replace our BMW rims with any aftermarket rims unless those aftermarket rims are Original renowned brands which are of good quality and sturdy enough to withstand the "shocks" transmitted from the road to the rims. So the ever so popular cheap replica rims from Taiwan is a big no-no! Also it is equally important to ensure that those aftermarket rims are indeed "EH2 rim" so that the RFTs will not dislodge from the rims when they experience sudden loss of tyre pressure due to a puncture.

 

[mizhan]

people using expensive rims can use cheaper tyres :biggrin:

 

[_M_]

Thanks for the reminder c-square :top: The second point is also highlighted during BMW Adv Driving program - that the benefit of RFTs can only be realised with "EH2" wheels.

On the 1st point, has anyone faced this problem? Wondering how common is it.. considering our bumpy & pothole littered roads.

 

[c-square]

Based on the above article, it is also clear that due to the characteristic of the RFTs, BMW has deliberately "downgraded" the suspension of our F30 to a softer one as a cheap and convenient way to compensate for the harsh feel. Sigh...why don't BMW give us the option to choose which suspension we want?

 

[_M_]

They do give the option.. check out the M Sport and M Performance catalogues..:burnout: