Review: 3DM Öhlins R&T kit + TMS camber plates + Syncro Design Works tension arms

[tdott]

I also have my own alignment machine, corner weighting scales, road force balancer, and tire machine.

That's awesome, I would like to add a rf balancer and tire machine to my garage. Already have a 2post lift and don't like taking my wheels anywhere to get done, they also never match the low/high spots from the tire/rim. But i'll need a bigger garage, otherwise i'll loose my 2nd parking spot in the garage.

[r4dr]

Great review. I'm glad you took the time to write this up. I have an E60 M5 and I've been thinking about a custom setup also. It is essentially the same suspension design, but a bit heavier of a car. New stock struts/shocks are stupidly expensive, and it's approaching the price of one of these high end setups, KW and Bilstein have setups, but sometimes I'm a glutton for punishment.

Eibach Pro-Kit springs + Bilstein B8s should be right around $1000 right? That would be well short of a full, $$$ setup. Are you DDing this car?

Edit: never mind I just realized Bilstein's catalog for E60 M5 cars is pretty bleak.

[IamFODI]

Well that was along time ago and I neither had the time or money to do have a decent car. Time has since passed and I have some toys and tools now, it's a hobby for me too. But even back 20 years ago there were standalone programs where you could model the kinematics. I'm sure there are ex Fomula SAE nerds that have done a bunch of modeling.

Absolutely. I didn't have and didn't find enough data to make a reasonable go of it (bump stops, lengths, etc.), but I'm sure people have done it and would be interested to see the results.

I also did quite a bit of chassis and ride development after college in an earlier life and I was impressed by your ability to articulate the subtleties of ride and handling trade offs. For obvisous reasons it seems only engineers tend to understand and can discuss these topics, it's a bit usually to see this level of intelligent discussion on forums.

🍻

I was catching up on more posts since I haven't been on the site for a while. I see you have your vibrations stuff sorted out. 6-7 lbs of force variation is pretty good, the default limit on the machine is set at 26 lbs if I recall correctly, but you can change that and the read out will tell you the exact force regardless. If it's really bad you can get a new tire under warranty, but that's tricky. I'm also in the NE so not very far away so if you needed to do an audit on your wheel/tire combo I could do it. I have a Hunter Road Force Touch.

Cool. Will send a PM.

spreadsheets are definitely valid. The fact that you even tried/did to calculate the ride frequencies and roll centers are impressive. The roll gradient is pretty important, but all this can be alot of theoretical tedium, where did you pick up how to do this stuff from? I used to use ADAMS and Matlab to crunch this stuff but you have to set up the model in program first, not hard, but tedious, a bit of a buzz kill too.

Slight correction: Roll couples, not roll centers.

Couldn't assume the roll couple numbers I generated were accurate because I didn't have ARB motion ratios. However, I thought that if I used the same ARB motion ratios for every setup I wanted to compare, I could still use the calculated roll couples to get very rough estimates of how handling balance might change.

Here's the main spreadsheet I used. Took a fair bit of editing,

For stock spring rates, I used 160 lbs/ft front and 550 or 600 lbs/ft rear. Saw those online in various places. For spring motion ratios, I used 0.96 front and 0.57 rear per this thread.

I got ARB rates from this page from Eibach..

[hansbrix]

spreadsheets are definitely valid. The fact that you even tried/did to calculate the ride frequencies and roll centers are impressive. The roll gradient is pretty important, but all this can be alot of theoretical tedium, where did you pick up how to do this stuff from? I used to use ADAMS and Matlab to crunch this stuff but you have to set up the model in program first, not hard, but tedious, a bit of a buzz kill too.

[hansbrix]

Well that was along time ago and I neither had the time or money to do have a decent car. Time has since passed and I have some toys and tools now, it's a hobby for me too. But even back 20 years ago there were standalone programs where you could model the kinematics. I'm sure there are ex Fomula SAE nerds that have done a bunch of modeling. I also did quite a bit of chassis and ride development after college in an earlier life and I was impressed by your ability to articulate the subtleties of ride and handling trade offs. For obvisous reasons it seems only engineers tend to understand and can discuss these topics, it's a bit usually to see this level of intelligent discussion on forums.

I was catching up on more posts since I haven't been on the site for a while. I see you have your vibrations stuff sorted out. 6-7 lbs of force variation is pretty good, the default limit on the machine is set at 26 lbs if I recall correctly, but you can change that and the read out will tell you the exact force regardless. If it's really bad you can get a new tire under warranty, but that's tricky. I'm also in the NE so not very far away so if you needed to do an audit on your wheel/tire combo I could do it. I have a Hunter Road Force Touch.

[IamFODI]

Great review. I'm glad you took the time to write this up. I have an E60 M5 and I've been thinking about a custom setup also. It is essentially the same suspension design, but a bit heavier of a car. New stock struts/shocks are stupidly expensive, and it's approaching the price of one of these high end setups, KW and Bilstein have setups, but sometimes I'm a glutton for punishment. Did you do any theoretical calculations or simulation? Seems like you also have some background in vehicle dynamics too. I also have my own alignment machine, corner weighting scales, road force balancer, and tire machine.

Thanks!

Man, I wish I had an actual background in vehicle dynamics. This is just a hobby for me, and not even one I've gotten that deep into.

When you say theoretical calculations, does that include plugging stuff into suspension calculator spreadsheets? 🤣 I did some of that mainly to try to assess ride frequencies and front/rear roll couples to see how feasible flat ride would be. As I mentioned in the second post, I ended up abandoning that effort, mainly because I couldn't imagine I had the juice to see it through when none of the real experts had even tried. Didn't do anything more sophisticated than that, let alone simulations.

[hansbrix]

Great review. I'm glad you took the time to write this up. I have an E60 M5 and I've been thinking about a custom setup also. It is essentially the same suspension design, but a bit heavier of a car. New stock struts/shocks are stupidly expensive, and it's approaching the price of one of these high end setups, KW and Bilstein have setups, but sometimes I'm a glutton for punishment. Did you do any theoretical calculations or simulation? Seems like you also have some background in vehicle dynamics too. I also have my own alignment machine, corner weighting scales, road force balancer, and tire machine.

[IamFODI]

Thanks for the props, guys. Just trying to put out something as honest, thoughtful, and useful as I can.

[tdott]

Great review!

[BMWahba]

Barry at 3DM is a great guy. He set me up with a similar setup for my e46. If anyone is looking to buy Ohlins, 3DM is the way to go for sure!

[IamFODI]

Did TCK dampers appear in your thought process at all?

Yes. Nice products with a great rep. They just didn’t seem like enough of a leap. I wanted something with a blowoff of some kind. Also heard from Obioban, who had run both on the same car, that Öhlins had the edge in a performance setting (though they were close overall).

[r4dr]

This is the quality content I'm here for. Did TCK dampers appear in your thought process at all?

[Obioban]

Now THAT is a suspension review!

[IamFODI]

Overall Verdict

- Quicker transient response than stock: Check.
- Comparably good limit behavior to stock: Check.
- Less feeling of mass: Check. Not enough to make me stop missing a lighter car, but enough for now.
- Stock ride height or close to it: Check.
- Reasonable NVH and ride quality: Close, but check.
- Equal or less weight vs. stock: Check.
- All boxes ticked in one shot: Check.

It’s not perfect. Somehow, I don't think it evinces the depth of engineering of an OE setup. If BMW had implemented dampers like this and optimized for this level of transient response and feedback, I'm sure they could have done a better job -- if only making it feel a bit less rough-around-the-edges.

Either way, a win's a win. I'm happy.

[IamFODI]

Handling, Feel, and Feedback

Predictably, the real payoff is here.

The steering feels like a tighter, heavier, more communicative version of stock. This was already one of my favorite parts of the car, and now so much of what I liked about it is even better. It’s fantastic. I wish I had more to say on this without being repetitive because it's hugely impactful on the driving experience as a whole.

There might be a bit more bump steer up front. But if there is, it's not by much.

Some one-wheel bumps seem to tug the rear end sideways more than they did before. Maybe that’s due to stiffer springs and dampers revealing/exaggerating the effect of worn bushings, or something. Interested to hear thoughts on this. EDIT: Not an issue after correcting tire pressures.

Overall body control is in a completely different league. The stock suspension, especially after so many miles, felt a bit floaty and floppy in transitions. I don’t want to make that problem seem worse than it was; it didn’t make the car feel like an econo-SUV or anything. It just took the edge off steering inputs more than I'd like and introduced delays in the chassis's responses. It was a confidence sapper in corners, as well as an exclamation point on the fact that this car is several hundred pounds heavier than I prefer. That feeling is gone now – or at least reduced to a non-issue for the kind of driving I do. I feel like I don’t have enough tire to unsettle the suspension, and that’s how I want it. The car feels an order of magnitude more confidence-inspiring in a corner. It still feels a lot heavier than I like, but it’s not rubbing my face in that fact the way it used to.

Handling balance has changed exactly as one should expect from the spring rates: more understeer / less oversteer / more rear grip. Classic result of bumping up ride frequency far more in front than in rear. I’m assuming this is why the steering response doesn’t seem any pointier than stock despite the drastically reduced compliance. I’m a little disappointed with that lack of pointiness; I was hoping for a more positive-feeling front end than I ended up with. But the car seems to get out of a corner much better, and oversteer is still accessible in every sense of the word. Overall, I’m not going to call this better or worse than stock because that depends on what you like. What I can say is that it’s a sensible balance and I’m enjoying it. It's nice to be able to lean on the rear end more while still being able to play with it.

The overall effect is that the car is much more fun to hustle than it used to be. It feels night-and-day better in transitions, gives better feedback, is even friendlier at the limit (as far as my noob self can tell), and inspires a ton of confidence. And crucially, the improvement over stock feels bigger the faster I go.

EDIT: track impressions here!