RFT on 19" Wheel changed to Standard Tire

Originally Posted by lionfish

When you guys say, RFT gives a harsh ride , What do you mean exactly? Harsh meaning, bumpy, stiff etc?

I think most peoples idea of a harsh ride is an abrupt feel in either the steering wheel or seat of the pants when crossing expansion joints, lane markers, pavement transitions that are perpendicular to the direction of travel , etc. The RFT sidewall is stiffer & shorter which give it the ability remain on the rim with little to no internal pressure. It is the nature of the design.

I drove a loaner 328 with 16" RFTs. The RFTs work actually really great on higher profile tires (50 and above) since the sidewall is tall enough to make up for their stiffer characteristics. I think it is so bad only because our tires have a shorter sidewalls.

alright, swapped my tires to PS2s that I bought a couple of months ago... what a difference does it make on my 18"... The ride is so much smoother. No more of this echoing bump sounds when I drive on road transitions. The low profile RFTs are just a bad idea. I also felt the difference carrying the PS2 and the RE50 RFT. You can definitely tell there is a huge weight difference. I am not going back that's for sure.

LOL..... A harsh ride is my CaymanS Base Suspension on 19" non-RFT..... The ride on my wife's 18" RFT's is much smoother. If I change it will be because of the increased cost not the ride.........

Originally Posted by MJET

LOL..... A harsh ride is my CaymanS Base Suspension on 19" non-RFT..... The ride on my wife's 18" RFT's is much smoother. If I change it will be because of the increased cost not the ride.........

Sorry to ask 2 stupid questions -
One - is there a possible replacement for the RFT of the E89 Sport Package rear tire (255/30/19) to standard tire, same size ? Am asking b/c when I look on bridgestonetire.com and michelinman.com, I can not find a 255/30/19 tire in non-RF models (PS2, for instance).

Two - Alternatively, on a factory Sport suspension shipped with 19", is it possible to install 18" tires without modifying the suspension settings and not messing up later with alignment / camber, etc ?

Thanks for your help.

(I owned a Z4 2003 and I know the pain of the RFT - am looking at purchasing a E89 only if I can get rid of the 19" RFT. If possible I intend to re-use the very good Bridgestone 18' RE760 Sport from my VW GTI on the E89).

1) yes, there are a number of regular summer tires that are available in a 255/30/19 Yokohama ADVAN Neova AD08, Goodyear Eagle F1 Asymmetric, Kumho Ecsta SPT to name a few. There is also no problem with upsizing. The car easily accommodates a 265 or 275. Some folks are even running 285 rears with the standard sport package adjustable m suspension.

2) yup, you can easily downsize to 18's if that's the route you want to go.

There are a few considerations about the 19's. Do yourself a favor and do a search on 19" wheels cracking. The style 296 wheels are cast wheels that in combination with the RFT are prone to cracking and bending. I know, because I bent 2 rims going over a pothole at 40 mph. I'm running regular tires now at 275/30/19. I'm hoping that the additional .24" sidewall height in combination with a softer sidewall will do a better job at protecting my rims.

Originally Posted by BugsBunny

Sorry to ask 2 stupid questions -
One - is there a possible replacement for the RFT of the E89 Sport Package rear tire (255/30/19) to standard tire, same size ? Am asking b/c when I look on bridgestonetire.com and michelinman.com, I can not find a 255/30/19 tire in non-RF models (PS2, for instance).

Two - Alternatively, on a factory Sport suspension shipped with 19", is it possible to install 18" tires without modifying the suspension settings and not messing up later with alignment / camber, etc ?

Thanks for your help.

(I owned a Z4 2003 and I know the pain of the RFT - am looking at purchasing a E89 only if I can get rid of the 19" RFT. If possible I intend to re-use the very good Bridgestone 18' RE760 Sport from my VW GTI on the E89).

Update .... Interesting read

http://www.e90post.com/forums/showth...=1#post8225396

I'm ditching my RFTs now that I've worn them out at 8k miles. My fronts were pretty scrubbed on an edge from autocross but thought I could get some more use out of them. I went in for an alignment and realized my rears had major inner wear. You can't get a lot of camber out of the Z4 without major mods but the tweaks done should protect my rears from this level of damage so early.

I wish I had gotten an alignment immediately after I got the car a year ago, like I did with my previous gen Z4. I'm not that hard on my car on the street and it was only 8K miles and three autoxs.

My next set is either going to be the Yoko Advan AD08 or Bridgestone RE-11 in a couple of weeks. I'm in the south and my lease is up in a year in a half and I know I'll have to put RFTs back on it to turn it in. Either tire should hold up for an autoX season and a track day or so and give me a good combo of street ride and autox grip. I considered a separate set of track wheels but I didn't want to make my husband do all that work (he changes wheels for events already).

I changed my 19 inch Bridgestone Potenza RFT's to conti Sport contact 5p's (non runflat). Made huge difirence to smoother ride and road noise. Also got a mobility kit from dealer which is an electric pump that runs off gig lighter connection. Comes with pucture sealantt in case of emergencies.

Difficult to get this size in other makes of tyre. (255/30's and 225/35's). I hear new Bridgestone S001 non runflat is quiet. I have Michelin Pilot 3's on my 5 series and they are the best in my opinion. (couldnt get the right size for the Z other wise i would have gone Michelin.). So far very happy with Conti's.

Still want to to do more sound insulation in wheel wells and door wells. I will use a combination of foam and Dynamat.

Run flats are a pain because it's hard finding a tire shop who will patch a hole if you run over a nail. Apparently BMW (and the tire manufacturer) prohibits these tires from being patched . So if you have even a tiny hole, you have to buy an entirely new tire (or a pair to keep the car balanced).

Check out my car's profile at: http://autop.in/alex (Is your car worthy of it's own URL?)

Originally Posted by alexfurm7

Run flats are a pain because it's hard finding a tire shop who will patch a hole if you run over a nail. Apparently BMW (and the tire manufacturer) prohibits these tires from being patched . So if you have even a tiny hole, you have to buy an entirely new tire (or a pair to keep the car balanced).

Check out my car's profile at: http://autop.in/alex (Is your car worthy of it's own URL?)

Not my experience: I picked up a nail in the tread area of my RF tire on my 335d. Took it to the local Continental dealer, I have Contis, they removed the tire from the wheel, removed the nail, patched and plugged the hole. I have been driving now for over 6 months with no issues.