Tuesday, July 28, 2009

Suspension Part 2

One of the most popular upgrades for ANY car is the shocks/struts and springs. These items carry the weight of the car and have a HUGE impact on handling, good or bad. Does your car bounce? Float? Drift? Rock side to side? Feel loose? Chances are your shocks are worn out. Most BMW suspensions last around 80k miles. Any more than that and you probably notice any or all of the above symptoms.

BMW offered two shock/spring options on the E46 and most other models: sport and non-sport. Each has a different spring rate (the stiffness), ride height, and shock absorber stiffness. Obviously "sport" is lower and stiffer than "non sport". A general rule is the stiffer the spring/shock, the better the car handles. But there is much more to a good set-up than just "stiffness" so you must choose a set-up that best suits your driving style.

Here are some tips for choosing the right suspension:
  • Prioritize your needs. Do you like canyon carving or comfortable commuting? Can you handle bumps and humps? How low do you want your car? What is your budget? What are the roads like where you live? Does it snow/ice? How often can you afford to replace tires, shocks, etc? Make a list and be realistic, lots of guys buy the super hard "corner carver" kits only to regret it after the initial giddy feeling wears off. And at $700-$2500, it ain't a cheap mistake to make!
  • Once you have your list of things you want, take some time and do your research. Talk to the guys at Turner Motorsport, Bimmerworld, and other shops that race what they sell. They can tell you what works on the track and what works on the street. Most are more than willing to tell you their experience if you just ask. Also check the online forums (caution:the public is ultimately one sided and few people have the ability to be objective with their views so keep that in mind when they tell you XYZ kit is the only way to go).
  • Keep in mind the "collateral damage" you might cause to your car. Damage? What damage? So glad you asked. Things like tire wear, shock life, and body damage from scraping can all be things you have to deal with. Personally I deal with a severe inner tire wear problem from being lowered, great for tearing up the twisties, not so great when I am always buying tires. And I can't tell you how many times I have scraped my bumper by pulling to far forward in a parking space. Also, the lower and stiffer you go, the sooner shocks tend to need replacement (especially in pot hole riddled parts of the world).
  • Buy the best kit you can afford. Just as the engine is the heart of your drivetrain, the shocks and struts are the heart of your suspension. Going with a more expensive but tried and true brand can save you hassle and time down the road.
A lot of people ask me what I have on my car (knowing I am on a very limited budget but yet really like to go fast) so here is my set-up. I bought my car with 112k miles. It had H&R sport springs on it when I bought it. But the shocks were factory non-sport units. This is a MAJOR NO NO! Lowered cars need special shocks that are designed to operate at the lower height. It can be downright unsafe to run a super low spring with stock shocks, so don't do it! I swapped the shocks/struts for Tokico "Blue" shocks. They have a lifetime warranty and cost $389 shipped to my door for all 4 corners. Lots of import guys have used them for years with great success. They are a good mix of stiffness and driveability and work well with the lowered set-up. After 40k miles of moderate to hard core use, they still perform very well. Not all that exciting I know, but hey, it's all I can afford!

Next installment we discuss sway bars! Don't miss it!


  1. Really nice reading. Keep up trhe good blog work.

    Do you take suggestions for future topics?
    A buyers guide for 2.hand BMW would be cool?

    Any way, thanks!

  2. What is 2.hand BMW? And yes, I take topics.

  3. I ofcourse meant advice on buying a used car, er sorry BMW.

    Many thanks.