Run flat or not?

[itf joegun]

Originally Posted by COOLZ4

The sizes are 235/35/19 front & 265/30/19 rear.

On the BBS CH-R I have a different setup:

BBS CH-R in mate black 8,5x19 front and 9,5x19 rear, Michelin Pilot Super Sport 225/35 and 255/30. This setup would also fit the 19" OEM tires.

[COOLZ4]

Very nice indeed!

[jannisa]

My conclusion is that on 18'' wheels you actually NEED rft tires to steer properly (at least if running semis is not an option).

On 19'' rims if you choose rft you must be a masochist.

[nicknaz]

Originally Posted by jannisa

My conclusion is that on 18'' wheels you actually NEED rft tires to steer properly (at least if running semis is not an option).

On 19'' rims if you choose rft you must be a masochist.

Haha, yes the 19" RFT ride was pretty stiff and there was some "crashing" over bumps but it wasn't completely unusable. I have certainly lived with stiffer aftermarket setups, so I suppose "acceptable ride quality" is somewhat of a personal choice

As for the 18s, I definitely agree there can be some loss in steering "feel" but I do wonder if most people will notice or care....

For what it is worth, with the Dunlop ZII in 235/40/18 and 265/35/18 (tread is closer to semi slick type but compound is still suitable for street use) the steering feel is very nice, and similar to with the stock RFT

[Gpwheels]

A 40 ratio sidewall is still low profile. I have 18 RFT's on my Z and find that they lose grip too easily. My previous car was a Nissan 350z with 18" 40 series Toyo T1R's and held the road like it was on rails. The rubber required to hold the weight of the car has to be so stiff, It just doesn't hold the road like a non-RFT does.

[itf joegun]

I have 18 inch winter wheels without runflat and it works quite well. Perhaps it also is very important which type of tires you have. I use the Michelin Alpin Sport PA4 and they are great.

The side wall topic is the reason why I use 225/255 instead of 235/265. The 265 setup is not stiff enough due to the higher side wall.

And by the way, if you buy the 19" inch wheel with the car, you get 19" inch RFT tires. It is unbelievable how less comfort they have. The only thing you can do is replace them, fast.

[RecycledTeen]

+1 on switching out the RFT's. On my E85 I went with a set of Hankook Ventus V12's (staggered set up) and difference was night and day.

[tranquility]

Originally Posted by jannisa

My conclusion is that on 18'' wheels you actually NEED rft tires to steer properly (at least if running semis is not an option).

I'm confused, so you're saying that RFTs are preferable if running 18s? I run PSS and don't feel that I lost any steering feel.

[jparnes1]

Originally Posted by Dave 19103

I wish BMW still offered the Fox Red interior like they did for the E85. It's a great color, especially with silver paint.

[hyper1]

Originally Posted by Dave 19103

+1 on switching out the RFT's. On my E85 I went with a set of Hankook Ventus V12's (staggered set up) and difference was night and day.

agree... I did the same

[jannisa]

Originally Posted by tranquility

I'm confused, so you're saying that RFTs are preferable if running 18s? I run PSS and don't feel that I lost any steering feel.

Having experience on 18s with rft, contis sc3 and bridgestone s007 the latter two have ALWAYS been ''vague'' at higher speeds and were building heat up really quickly on curvy roads actually to the point of feeling like driving on balloons after a while.

[tranquility]

Originally Posted by jannisa

Having experience on 18s with rft, contis sc3 and bridgestone s007 the latter two have ALWAYS been ''vague'' at higher speeds and were building heat up really quickly on curvy roads actually to the point of feeling like driving on balloons after a while.

Anyone else reach this conclusion? If yes, maybe I'm not driving fast enough. I don't feel any difference in terms of inferior steering when I made the switch from RFTs to nons. All I know is that they feel more planted.

[CeEl]

Originally Posted by tranquility

If yes, maybe I'm not driving fast enough.

Yep, that's our issue right there -- we are not driving fast enough!

[tranquility]

Originally Posted by CeEl

Yep, that's our issue right there -- we are not driving fast enough!

I wish that I could. The damn police here are like Nazis, any ticket will make one's insurance rate jump. I don't even mind the ticket cost, it's the insurance repercussions that's annoying.

[nicknaz]

Originally Posted by tranquility

Anyone else reach this conclusion? If yes, maybe I'm not driving fast enough. I don't feel any difference in terms of inferior steering when I made the switch from RFTs to nons. All I know is that they feel more planted.

I do agree with jannisa, that in general going to non RFT makes the turn-in more "vague" due to the generally less stiff sidewall of the non RFT

If you have ever switched from a competition style summer tire to a winter tire, you will have experienced an extreme case of what jannisa is talking about....

It is also is possible the PSS has a stiffer sidewall than the 2 non RFT jannisa is commenting on.

Also, I think the heat build up depends on the specific tire, as opposed to RFT vs. non RFT. Even among the factory RFT, I have found the RE050A (the E89 19" OEM) heat build up is worse than RE050A I (E89 18" OEM) and RE050A II (E90 17" OEM). I have tracked all 3 of these RFT while trying to burn off the the treads....

[jannisa]

Very interesting find nicknaz regarding differences between 18'' and 19'' rft.

Well the pss(s) and michelins in general are renown for excellent grip but notorious for very soft sidewalls resulting in heat inflation. A couple of friends with e46 m3s warned me against choosing them for that matter.

Don't get me wrong, bragging to being able to bring a product beyond its limits is foolish if not criminal, I actually drive on public roads like a virgin.

It's just that few occasions when you have the opportunity to enjoy that 300+ hp car and at that moments non rft were extremely limiting.

[nicknaz]

Originally Posted by jannisa

Well the pss(s) and michelins in general are renown for excellent grip but notorious for very soft sidewalls resulting in heat inflation. A couple of friends with e46 m3s warned me against choosing them for that matter.

I have gotten similar feedback about the PSS not handling heat very well and chunk at the track.

I guess I have never been super impressed by Michelins. They have always seemed to be an overrated tire, and the front runners in the street tire classes I've seen or heard results from are never using a Michelin tire.

Good upgrade from stock tires, but not a competitive tire...

[Gpwheels]

If not michelins, than what do you recommend? I don't track my car, but I like to push it when I can. Right now I am looking at pilot sport a/s3's, potenza re 970a/s, or Pirelli P zero Nero a/s. I want all-seasons as I live in an area with a short summer and all-seasons buy me a month more driving at each end of the season. I was leaning toward michelins, but haven't decided yet. Looking for some opinions.

[nicknaz]

Originally Posted by Gpwheels

I like to push it when I can. .

Personally I think you would be better off with the factory summer RFT and switching to winter WFT.

I think the winter RFT will have better turn in feeling than all seasons....

[mbetoni]

Originally Posted by Gpwheels

If not michelins, than what do you recommend? I don't track my car, but I like to push it when I can. Right now I am looking at pilot sport a/s3's, potenza re 970a/s, or Pirelli P zero Nero a/s. I want all-seasons as I live in an area with a short summer and all-seasons buy me a month more driving at each end of the season. I was leaning toward michelins, but haven't decided yet. Looking for some opinions.

I put the PZero Neros on my first E85 (replacing Gen 1 RFTs) and was VERY happy with them. I drove that car year-round and the ride was greatly improved and they offered a confident feel in colder weather. FWIW.

[Gpwheels]

When changing to non-RFTs, do most of you stick to the factory sizes for both rim and tires? I have 18" rims. I don't really want to compromise ride quality, but I am looking for a bit more grip. Would 19" wheels be rougher than 18" RFTs? Just looking for some opinions

[Tengocity]

Another vote for NON runflats on the E89. If ever there was an overused cliche then night and day difference is one of them, but truly the runflat tyre on this car ruins it completely here in the UK with the terrible roads we have.

I've gone to Michelin Pilot Super Sports and now completely love the car. The ride is firm, but the car is not harsh, and the damping feels suitably sporty and expensive. This is on 19's too.

I have 17 inch winter wheels that are non runflat too and I didn't feel that the were that much better so I'm very happy with my big wheels- they look tremendous!