Best bang for buck: Perf Sus or Lighter Wheels/Tires

[inline-6]

I have a non-sport 128 with stock RFTs, have been looking at a few upgrade options and am wondering what to go with first.

It's come down to getting the BMW performance suspension, or 17 235 45 Extreme Contact DWs on O.Z. Ultraleggera wheels. I've calculated the weight saving at 11.7 lbs/per corner.

Prices come out fairly close, which do you think would make the biggest difference?

[Freon]

Strictly speaking, stickier wider tires will give you more absolute grip than a slight suspension upgrade. You can improve handling a bit by adding front camber, which I'm not sure the BMW performance suspension will help much with.

Your RFTs will wear out eventually anyway, and having a spare set is nice.

I would steer you away from BMW suspension, Contis, and OZ wheels. You should consider a KW suspension with something to increase front camber, Dunlop or Michelon tires (ZII or PSS), and Apex ARC-8 or EC-7 wheels in the special 1er fit to maximize tire size. You'll get more bang for the buck. Keep in mind what happens if you pop a tire without RFTs as well. Perhaps getting maximum tire in the back isn't a big deal since you have a 128i, not as much power to put down so the OZs are ok, but definitely try to max out the front to 235/40/18 or 235/45/17. You need a +45 ET for that. Rear generally should be higher, +50-60, but few wheels are available that have such a high offset.

[inline-6]

Thanks Freon.

I'm not necessarily looking for maximum grip - more something that I will feel and enjoy everyday.

From a 'feel' perspective, would your recommendation still be the same?

[vantagesc]

I would guess that...

Eliminating the RFTs would give more grip and reduce some of the bounciness that RFTs cause, but at the same time, the softer sidewalls of non-RFTs will lead to slight decrease in steering feel / responsiveness. I'm not planning to change to non-RFTs until my stock tires wear out to save $$$.

In theory, lighter wheels will allow the stock suspension to react faster. 11 .lbs per corner is a nice weight savings, but I'm not sure how much different it will feel.

Going from non-sport to performance suspension (or aftermarket coilovers) ought to change how your car feels substantially, based on the difference between my 135i sport and my family's 328i non-sport. Forum members are also reporting better feel on the street with M3 front suspension parts. If you eventually change to non-RFT tires, the performance suspension should still ride quite well...

[631twentyeighteye]

I would say perf suspension. I had floppy 128 suspension and RFTs, the worst of both worlds. I put in 2012+ linear springs from my buddy's 135i along with the shocks, and then ventus v12's in 135i sizes, and it's awesome. The car is very comfortable daily driving(50 miles 4 days a week), and is also firm enough to give great feed back and with minimal body roll. Eventually i will probably put in eibach springs, just for looks since it still sits a bit higher than i'd like.

Ideally i'd like to go with a square setup, 225-40-18 on 18x8 v701's in hyper silver.

[doublevanosrc]

Quick question, is the Perf suspension designed to work with runflats or non runflats??

[Ender_]

If you have to pick one change to do first, go with 18" Apex ARC-8 wheels with Michelin PSS Tires in a 225/235 front and 255 rear setup.
http://www.apexraceparts.com/ARC-8-1...ies_p_132.html
I'm always shocked when I pickup my track ARC wheels at how light they are.

From there move on to KW v3 coil-over setup. Not sure there would be a whole lot of a point going to 135 msport suspension for all the trouble and cost.

[vantagesc]

Originally Posted by doublevanosrc

Quick question, is the Perf suspension designed to work with runflats or non runflats??

Everything I've read on this forum has suggested it was designed for RFTs, but I've never seen confirmation of this from a BMW document. It makes sense though, since BMW doesn't tell you to change tires when you install it.

[bluephobic(1)]

Originally Posted by Ender_

If you have to pick one change to do first, go with 18" Apex ARC-8 wheels with Michelin PSS Tires in a 225/235 front and 255 rear setup.
http://www.apexraceparts.com/ARC-8-1...ies_p_132.html
I'm always shocked when I pickup my track ARC wheels at how light they are.

From there move on to KW v3 coil-over setup. Not sure there would be a whole lot of a point going to 135 msport suspension for all the trouble and cost.

Or if your feeling agressive try 245/25 275/35 it fits fine with front camber plates

[RimasRS]

Do suspension first. When your tires will wear out replace them with non runflats.

[TheSt|G]

Originally Posted by vantagesc

Everything I've read on this forum has suggested it was designed for RFTs, but I've never seen confirmation of this from a BMW document. It makes sense though, since BMW doesn't tell you to change tires when you install it.

No car is "designed" for RFTs other than the lack of a spare tire well.

[MightyMouseTech]

Tires are THE most important part on a car for performance. Everything else is just there to make the tire perform as well as it can IMHO.

[vantagesc]

Originally Posted by TheSt|G

No car is "designed" for RFTs other than the lack of a spare tire well.

I understood the question to be asking about the performance suspension's valving / spring rate choice. At the very least, I would think that the choice of valving for the shocks would be affected by the tire choice.

Originally Posted by MightyMouseTech

Tires are THE most important part on a car for performance. Everything else is just there to make the tire perform as well as it can IMHO.

I agree with this, though if the OP wants "feel" instead of performance/grip, then the choice is less clear.

[andrey_gta]

I will say suspension, because a car with a nicer /meaner stance, even on conservative BMP Susp will make you happier to look at it and drive it.

On the street the Runflats are not that bad. My fathers e46 has a set of e90 runflat 16's from 323i and its not bad, just a loud basket ball bounce on large bumps and the street handling was not compromised.

The decisions with suspension for 128i is considering what kit you want:
1) Decide if you care about the difference vs m3/1m for the rear shock mounting, if you do stop and research a kit like Ground control school/street coils or HPA's many offerings(just spring + shock kits)
2) spring + shock options:
- Kits with H&R springs usually have more of a rake in the front then Eibach( Also H&R OE springs which are mild drop had some issues in the rear, they apparently supplied e90 springs which jacked up the rear)
- Kits with koni Yellows are most desirable, especially HPA's version that has the rear adjustable
- Koni FSD + BMP or 2011+ 135i springs is gettign food reviews
- Eibach Pro 1+2+3 kit also comes with front + rear sway bars that may be better than Performance Suspension sways which i think for the 128i are just Msport/135i sways. The whole Eibach kit seems to be priced at 1k, not a bad deal for a non sport 128i. Just look up the drop amount before you heavily consider this.
- Also, installing a rear sway from BMP or Eibach is perfect time to install m3 subframe bushes and be miles ahead of any comparable 128i
- Koni Str.T kit( koni orange dampers + H&R sport springs) , a new product, has been reviewed by one e90 guy and hes happy with it for the street. Koni orange dampoers are reviewd to be Yellows set to 1/4 to 1/3 turn from full soft. Its hard to find though in north america.
3) Coilovers
- Taiwan based offerings from BC racing( swift spring option is available) or CKS with Swift or SonicTuning etc ($1-2k)
- Value kits from ST/Vogtland/KW v1 ( $1k)
- More advanced options

[Ender_]

Originally Posted by RimasRS

Do suspension first. When your tires will wear out replace them with non runflats.

I kinda of agree with this point if they are new RFT's, unless of course you can sell them.

I hated the RFT's, why do you think M cars don't come with them?

[631twentyeighteye]

I don't get why everybody is trying to tell him to stick the fattest tires he can under it.. it's a 128. I don't have many traction issues on my 225 blizzaks, 255 PSS would be retarded. like i said, 225 squared setup is ideal, it enhances the 128's best feature, it's handling.

I went to msport suspension because it was less than half the price of coil overs with install. Plus they were brand new with 11 miles on them.

[andrey_gta]

^^ I agree. My 128i is very fun on 225 winters

Although I think I will be replacing my 18" tires with 255 rears and 225 fronts because its easier to resell to e90 guys. Will compare prices agaisn soon and perhaps stick to stock 18" sizes or just 225 in front

[simianspeedster]

Originally Posted by RimasRS

Do suspension first. When your tires will wear out replace them with non runflats.

This is my best advice as well.

Heavy wheels and heavier, stiff runflats certainly challenge any suspension more than light wheels and lighter, more compliant tires, but I believe a better suspension will help in other ways that have more of a positive impact for the cost.

Do you feel that the car is not as responsive to directional changes as you'd like? Do you dislike the way it floats and bobs over rises and dips in the road surface? Does it feel like the car is kind of throwing its weight around in a less controlled manner than you expect in a BMW? Then you want better suspension. Better tires will improve the ride and the tires' connectivity to the road, hence ultimate grip, but it doesn't sound like that's your top priority if you had to choose. Better suspension will offer more of an improvement to the car's body control and its responsiveness to your input.

Also, I'll echo what some other posters have mentioned: the 128i doesn't need to be stuffed to the gills with tire width because it's a relatively light car with near perfect 50/50 weight balance and it doesn't have the low-end torque of the 135i which demands more rear traction. Do your research and figure out what makes sense for you, but it may make sense for you to run a square setup with moderately wide tires all around (225s, for example).

When my 128i arrives, I'll be dumping the stock suspension, wheels and tires and replacing them with the BMW Performance Suspension, lightweight 18x8" wheels all around and Michelin Pilot Super Sport 225/40-18 tires all around. It won't be a track champion or offer maximum grip in ever situation, but that's not what I'm after. I want a new BMW that drives more like the BMWs of yore -- firm, but not harsh, well controlled and grippy without relying on its tires so much that it can't dance. It wouldn't please everyone, but it'll be the right mixture for me.

[inline-6]

Thanks everyone, lots of good advice and more things to consider.

I'm leaning towards the suspension at this point - still lots of research left to do. I like the idea of a full kit so the Eibach 1+2+3 is looking good aswell as the BMW PS.

Can anyone vouch for a good indy shop in the Greater Toronto Area? I'm in Kitchener/Waterloo.

Once my RFTs are worn down I'll go back and look at wheels/tires again. Yeah I think for the 128i a square setup will be fine and hopefully reduce the understeer a little bit. 225 seems to be a nice balance of a little more grip without having to worry about any clearance/fitment issues. I will be doing some tracking but nothing crazy - just to have fun.

Thanks again for all the help - great forum!

[Inconspicuous]

IMHO, in order of impact/priority:

1) Tires - this is the only one which will improve outright grip, response, braking, and acceleration

2) Suspension - the way a suspension improves performance is by keeping tires in their "happy place" for more of the time, but your maximum grip is ultimately determined by your rubber, not your springs/dampers

3) Lightweight wheels - this will reduce unsprung weight, which will help your suspension to do its job, which is to keep your tires in their "happy place."

So if your goals are performance-oriented, it stands to reason to upgrade in that order. If, however, your goals are aesthetic, it could be argued that you should reverse the list entirely, as wheels will be the most dramatic change in looks, followed by a drop, and lastly tires.

[bogart]

tires, wheels, suspension

[simianspeedster]

For those of you suggesting tires first, you may have missed the OP's clarification earlier in the thread:

Originally Posted by inline-6

I'm not necessarily looking for maximum grip - more something that I will feel and enjoy everyday.

From a 'feel' perspective, would your recommendation still be the same?

If maximum outright performance and grip were the OP's goals, maybe tires first, but he's talking about feel, and driving feel has more to do with suspension. Tires will have much less impact than suspension when it comes to body control and responsiveness under normal (i.e. non-track) driving conditions. These are the things you notice every day, even driving in a straight line, but maximum performance and grip are rarely exercised in real-world driving.