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[fourtailpipes]

Originally Posted by Dackelone

royrathbun - The problem is that for the German TUV they say the max size tire you can mount on the rear 8.5 inch wide wheels is a 245 - when they look up the info in their tire/wheel books. My tire shop also pointed this out. But I also told them I do not have to go thru TUV since I am in the Army (with German cover plates and all). Then they were Ok with doing it. It is only 10mm's anyway. I would tell your tire shop what you want to do. I would go to a shop that is near a US Army base and I bet they are more willing to do this or have done this for us Ami customers.

I used ReifenWagoner (tire chain) - IF that helps you at all.
Dackel

would it be possible to take the wheels off the car and bring them to the shop loose? just tell them it's for a kit car or something with no enforced specifications.

[dtwyim]

Originally Posted by Dackelone

I agree with this statement too. IF you are gonna keep the stock suspension - they stick with run flat tires in the OE size. The steering response is very good with the run flats.

I am still happy I went with Michelin PS3's. But the steering response isn't as good as with the Dunlap run flats the car came with. The PS3's aren't that bad - but not as sharp in steering as the OEM run flats. But the better ride is really nice and the overall perfoamace is very high. Plus I plan on installing a //M3 suspension bits this year.


Dackel

I am thinking getting Michelin PSS (not PS3) upsized to 225/255 with stock rims and suspension. Now I am having second thoughts. Any body else have comments?

I know Gill says there will be no rubs. But I read above in this thread that rub might be possible under some circumstances. I have no plans to roll the fenders.

Comments and suggestions appreciated.

[Dackelone]

You can not go wrong with any Michelins. They are such great tires. I was out driving today and wondering how much I don't miss my runflats. The Michelins are truely a great tire. Even if you get PSS - you will be happy. I would not loose too much sleep over going with the larger tire size.

[dtwyim]

Originally Posted by Dackelone

You can not go wrong with any Michelins. They are such great tires. I was out driving today and wondering how much I don't miss my runflats. The Michelins are truely a great tire. Even if you get PSS - you will be happy. I would not loose too much sleep over going with the larger tire size.

Thanks Dackelone. Are you saying that you are happy with sacrificing some steering response for better ride? I think you might be upgrading your suspension. I am not planning to since i don't track my car and the stock suspension is stiff enough for my poor back! My OE tires are Bridgestone Potenza RFT. I wonder if it is much different than your RFT?

[John_01]

I have driven on the Bridgestone Potenza RFT on a circuit at the BWM driver training. When pushed to the limits, it seems to me the stiff sidewalls of the RFT doesn't offer any benefit. IMO, you will get better overall performance with conventional tire with the appropriate inflation pressure (more than the spec on the compliance plate).

Personally I dislike the steering feel of run-flats for road usage because there is an awful lot of tramlining. Getting rid of run-flats is the best thing you can do for your car. Especially the Bridgestone Potenza RFT II is one of the harshest, more noisy tires on the planet.

[romak47]

Originally Posted by Diver

I see a lot of talk in this forum about running 225/255 tires instead of the stock 215/245 setup.

Are there any downsides to going up a size on a 135i? This would be on an otherwise completely stock car that is not driven on the track ever.

You will be fine going 225 and 255 on OEM's but ride will feel floaty to you without suspension upgrades.

If you get a drop and have a passenger in the car, you may rub on certain dips.
I have 225 and 255 dunlop dirrezas on stock 261's and i rub on right rear when i go over dips and bumps i normally never rubbed on before, as long as i have a heavy passenger with me.

[Dackelone]

Originally Posted by dtwyim

Thanks Dackelone. Are you saying that you are happy with sacrificing some steering response for better ride? I think you might be upgrading your suspension. I am not planning to since i don't track my car and the stock suspension is stiff enough for my poor back! My OE tires are Bridgestone Potenza RFT. I wonder if it is much different than your RFT?

Yes, I am very happy with my non-RFT Michelin's. I gave up a tad bit of steering response for a MUCH better ride quality. And the dry and wet grip is way better now than with my OE Dunlap RFT's. What you will notice most is the car doesn't hop & skip around (over bumps) as much as it did with the RFT's. Even going over little dips on a flat road with RFT the car's tires would hop or feel like they would hang up in the air... now the car's suspension feels like it is working more in harmony - togther.

I would not go back to RFT's.

I do think I will go with the Performance suspension and probaboy the M3 control arms. But that is down the road some.


Dackel

[janus77]

i've just installed 225/255 Z1's, went for drive on the weekend, no rubbing.

[PA135i]

I have to be honest. Of course this is my opinion. I just bought the 225 / 255 setup in Conti extreme DW's. The tires are great and the looks are fine also. But, I do notice a loss in tight handling as opposed to the OEM Bridgestones.

When these wear out I will be going back to the original setup. I do miss the razor sharp handling they brought. The Bridgestones also look great and look wider on the car. The 225 / 255's are taller tires and dont look wider to me. maybe I'm wrong here, but the footprint does look narrower.

[ZIPNBYE]

Originally Posted by kja325ci

I have to be honest. Of course this is my opinion. I just bought the 225 / 255 setup in Conti extreme DW's. The tires are great and the looks are fine also. But, I do notice a loss in tight handling as opposed to the OEM Bridgestones.

When these wear out I will be going back to the original setup. I do miss the razor sharp handling they brought. The Bridgestones also look great and look wider on the car. The 225 / 255's are taller tires and dont look wider to me. maybe I'm wrong here, but the footprint does look narrower.

Sorry dude, but apart from the slight increase in height, your thoughts are completely wrong.

From a track perspective, any runflat tire is numb compared with a traditional tire...the crisp turn in you think you had was actually numb.

[PA135i]

Originally Posted by ZIPNBYE

Sorry dude, but apart from the slight increase in height, your thoughts are completely wrong.

From a track perspective, any runflat tire is numb compared with a traditional tire...the crisp turn in you think you had was actually numb.

Sorry dude, as I said "this is my opinion" and my dollars at work here. And your thoughts are completely wrong. The OEM bridgestones, do look much better and handle better than these Conti's. The softer sidewalls are very apparent on an off ramp. The car was tighter with the OEM run-flats. I have been driving Hi performance autos for more than 20 years. I don't agree at all with your interpretation on what I was feeling from the tire... LOL

[128vert]

What tire repair kit do you carry in case of flats when you are running non-RFT's?

[Dackelone]

You know this is why I decided to go with Michelin's... bc although the Conti extreme DW's did score well on TireRack's website... some of the feed back here was less than spectacular. I seem to remember a few guys here saying how the streering response was not that great and how the sidewalls were soft. This is why I went with the PS3's - even though they were (more)$$$.

I respect "kja325ci" opinion. I am curious though... Do you have Conti extreme DW's (summers) or DWS (all seasons)?


Dackel

[ZIPNBYE]

Originally Posted by kja325ci

Sorry dude, as I said "this is my opinion" and my dollars at work here. And your thoughts are completely wrong. The OEM bridgestones, do look much better and handle better than these Conti's. The softer sidewalls are very apparent on an off ramp. The car was tighter with the OEM run-flats. I have been driving Hi performance autos for more than 20 years. I don't agree at all with your interpretation on what I was feeling from the tire... LOL

Well, while you've merely been driving hi-perf cars for 20yrs, I've been racing and teaching high-performance track driving (BMW Club of Canada and Porsche Club of America accreditations). Not a single person with any experience on a track will tell you that run-flats are the way to go. While it may feel as though the turn-in's tigher (simply by a stiffer sidewall) it doesn't actually mean that you've got more grip, as the contact patch of a tire has to transition and change while cornering. The stiff sidewalls of run-flats numb that and ultimate grip is less. Ride is worse too.

I too can respect your opinion, but it's yours, and not based on anything more than your butt. I'd rather trust mine.

Originally Posted by 128vert

What tire repair kit do you carry in case of flats when you are running non-RFT's?

I've got BMW's mobility kit, along with the jack kit, and a Dynaplug kit (with a pair of pliers to remove the offending nail/screw). There are many kits though, as all you really need is the compressor.

Originally Posted by Dackelone

I respect "kja325ci" opinion. I am curious though... Do you have Conti extreme DW's (summers) or DWS (all seasons)?

His original post mentions that they're the DW model.

[fourtailpipes]

Originally Posted by ZIPNBYE

Well, while you've merely been driving hi-perf cars for 20yrs, I've been racing and teaching high-performance track driving (BMW Club of Canada and Porsche Club of America accreditations).

ah yes, the highly-coveted bmw and pca instructor accreditations

you may be right, but unfortunately your resume doesnt mean much on the webernet.

[PA135i]

Originally Posted by 128vert

What tire repair kit do you carry in case of flats when you are running non-RFT's?

I have the Conti Kit. Tirerack sells it for around $80. The kit instructions do say that the can needs to be replaced every four years whether you use it or not.

[PA135i]

Originally Posted by ZIPNBYE

I too can respect your opinion, but it's yours, and not based on anything more than your butt. I'd rather trust mine.

Yes, I'd much rather trust my butt.

I never said I race with runflats. Aggresive driving is what most of us do who own these cars.

[Bimmer_Freak]

Could it be the wider 225's up front that causes a loss of steering sharpness?

My thoughts are that the wider tyres might protrude out past the rim, therefore allowing more room for sidewall flex?

I'll be sticking to the stock sizes when i finally go non-RFT.

[John_01]

I think that people who criticise the steering response of non-RFT probably don't have enough air pressure in them. Try around 36 PSI, then see if the situation improves.

[mosx]

I have a 235/255 setup on the BMW Performance Suspension, no rubbing anywhere. Even with 4 200lb+ guys in the car.

[M34lnch]

Originally Posted by ZIPNBYE

Sorry dude, but apart from the slight increase in height, your thoughts are completely wrong.

Hello, I've been enjoying reading this thread. I'm not understanding why a 225/255 with non-RFTs would result in a slight increase in height over the stock RFTs. Would someone explain this?

[GotM]

Originally Posted by M34lnch

Hello, I've been enjoying reading this thread. I'm not understanding why a 225/255 with non-RFTs would result in a slight increase in height over the stock RFTs. Would someone explain this?

The increase in height should be due to the change in tire size, not RFT to non-RFT. Assuming that the same aspect ratio is used for stock to larger tire.

Using info I found on Tire Rack (Pirelli P Zero specs)

Stock rear tire size
245-35-18 => 24.5" overall height

Using the larger 255, same 35 aspect ratio
255-35-18 => 25.2" overall height