550isport

I am going to modify my 550's suspension. The springs are too soft for my taste. Two options: Dinan Koni upgrade or OEM retrofit with the LCI 550 sport's new M sport tuned suspension (shocks, springs and bump stops). Assuming prices of the two are essentially the same what are the pros and cons? The new LCI sport suspension is "M tuned", aka M technik, like my last BMW...which I loved. Also, the LCI set up is designed for use with 19 inch wheels with non-runflat tires; the same setup I have... I won't do the JRZs through Dinan b/c its too expensive for a lease. I'm concerned that the Koni Dinan suspension won't be stiff enough, or won't be a big enough difference. M sport suspensions are pretty stiff. What option would you choose? Even once the 08' 550 sport hits the pavement, it will be hard to judge between the two...? Any thoughts?

DRP

pmmeke

are you sure sport suspension option for non lci and lci version is different? What s the difference?

550isport

I can't speak for other markets, but in the U.S., this is BMW's press release for the 08' 550i sport:

To further enhance performance, the optional 550i Sport Package newly includes an Aero Kit, modified-calibration Sport suspension, 19? wheels and performance tires, and a short shift lever, in addition to Multi-Contour seats with lumbar support, sport steering wheel, sport exhaust system, and Active Roll Stabilization.

Its a known issue among 550/545 sport owners who prefer a stiff ride that the U.S. sport package through 07' is a little too soft...for a BMW. So now with the LCI in the U.S., BMW has moved up to 19 inch wheels with NON RUNFLATS (a veritable breakthrough) and newly tuned sports suspension. My guess is the springs, shocks and bump stops are all just a little stiffer and I believe the specs on this new sport suspension are set by Motorsport Division, not BMW AG. The active roll stabilization (a.k.a. dynamic drive) system and settings probably stay the same. Presently I have non-runflat snows and the OEM 18 inch wheels on my car, an 07' 550i sport. With this setup, it rides very well, although still a bit soft. With my 19 inch wheels also with non-runflats, the handling and ride are messy for a sport package BMW. It tramlines considerably and the rear end squirms under full acceleration. The "modified-calibration" sports suspension is almost a necessity with the 19s. If BMW sold the 550i sport with the non-LCI U.S. sport suspension and the 19 inch wheels and 30 series non-runflat tires, magazine reviews would nose dive. Amazing how one inch in wheel diameter and one step in tire profile effects the handling so much.

So, I'm confused about which suspension to buy since its unlikely to find anyone who had driven both 1) a Dinan Koni 5er; and 2) the closest thing to an LCI 550sport which is likely a 540/550i M sport (which they have never sold in America). Also, I'm pretty sure that the Dinan suspension upgrade, which I don't believe has changed in the last two years that it has been available, is tuned for use with the OEM 18 inch wheels and runflat tires, neither of which I have on my car (save for the winter). So I am at a crossroads. I'm leaning toward the OEM retrofit if the prices aren't outrageous.

Any thoughts? Educated guessing and speculation is welcome.

DRP

EuroCarFan

I believe the Dinan suspension is also tuned to their 19" wheel package so it's not just for 18s. Also, the Konis are adjustable so you can soften or stiffen them to your liking.

That said, I don't have experiences with either... haha

tachyon

550isport - You are on a worthy mission. The Dinan suspension gets praised by many regular E60 and M5 owners, so I'm sure you would like it. However, I put Dinan's stage 1 suspension on my 1995 540i Sport and found it too stiff. So I'm leaning towards the OEM bits - but I plan to wait until we hear reviews on the new M set-up (or even test drive one).

JetBlack

Dinan actually tunes their suspension to whatever size wheels BMW applies to the sprot package. They understand that 95% of the cars that get the suspension will NOT have the Dinan wheels.

EuroCarFan

Ahh...thanks for the info!

heezy545i

DRP, didn't you already have a thread about this?

If want to upgrade, just go with the Dinan. I'm sure the new OEM suspension is improved, but like all OEM suspensions, it will be a compromise between sport and comfort. The dinan is also somewhat of a compromise, but it will still be seen as an upgrade over even an LCI m-sport suspension.

I think I've mentioned it before, but just buy the shocks directly from koni, then couple it with your choice of spring. You can even get the dinan springs if you so please. Either way, this will save you money.

I wouldn't buy into the whole dinan warranty or even the implication that dinan re-valves the shocks. If it's anything like on past BMWs, the dinan konis and the off-the shelf konis will have the same part number. Same part number since they are no different, just that one costs more. Check and see for yourself.

EuroCarFan

Oh yeah, this thread sounds familiar.. hahaha

Roleez

I have driven Dinan's own Dinan5, a 2004 545i which has Stage 1 Dinan/Koni suspension. I've also sampled Dinan's Dinan3, a 2006 330i. The Dinan3 has a much stiffer, bouncier, tighter ride, almost close to that of the M-tuned suspension (according to Dinan). The Dinan5 suspension setup is much more civilized ... less bouncier on bumps/ruts yet still very tight when cornering. I loved the Dinan5 setup so much, I'm having it installed on my 550i as I type this. I'd go for the Dinan setup for your car rather than OEM parts for the '08 model year. Plus the Dinan setup is adjustable.

As an aside, I've also sampled the M5 suspension which is quite bouncy in the stiffest setting, much like driving the Dinan3. If you fancy a bouncy, less composed ride, the M suspension might be to your liking. But for a more civilized ride with the ability to corner on rails, go for Dinan's Stage 1.