Suspension upgrade question...

I have replaced all of the front control arms and links and have replaced the OE struts with the Bilstein B6 front and rear. Still using the factory springs, however. The front strut mount bearings are also new. On roads where the concrete joints are raised and the streets are just plain crummy with holes and bumps, the ride of the car is absolutely punishing. I'm more concerned with punishing the car than myself, and so my question: What, if anything, can be done to smooth out the ride a bit? I heard somewhere that coil-overs can provide a better ride for the car but I know nothing about them or how they can achieve this over the stock suspension. If anybody has experience with a tried and true mod for this condition, I would love to hear it! 80% of the time the car ride is just fine, but bad roads really bug me, thinking I am harming my car. I don't ever track this car or drive aggressively so if the performance is diminished a bit, no problem. I was even thinking a tall sidewall would be ideal, but that doesn't appear to be an option that is ever going to be available. Thanks very much, guys! -Tom

I know what you mean. I have a 997.2 and a 986 Boxster. The Boxster on 17s is much more compliant than the 18s on the 911. It's so much better we prefer it for trips.

Thanks, John! I would like to try the 17's so I put them in a "tire calculator" to compare to my 18's. The fronts on the 17's would give me .3" more sidewall (8% more), but the rears would give me .2" less (5% less) on the 17's. It is a tad confusing, but the rears on the 18's are a full 1.3" longer in diameter than the 17's but have less sidewall, while the fronts are only .3" longer in diameter than the 17's and have more sidewall. I'm not seeing enough difference here on paper too justify rolling the dice on a switch to 17" wheels, but thanks a lot for the input on the Boxster wheels. What tires do you run on each car? I have the Conti Ex Con Plus on currently but was thinking to try the Michelin next time around. But then I read somewhere that the Conti is actually a better riding tire. What do you think???

Tire Rack rates tires on various parameters, including ride. You might look at their site, pull up the tires you have, than compare to another brand to get some input. Different car (951) but I went from Bridgestone run-flat Pole Positions to Michelin Pilot Sport 4 S, and found the ride improved. If you are running on run-flat tires, that will also increase impact harshness. A taller sidewall should improve ride quality. As you go down in sidewall aspect ration the sidewalls get stiffer to help responsiveness but also transmits more impact shock to the suspension and you. I run 18's on my 951 which came on 16's. When i put the 16's back on with stock aspect ratio sidewalls (55 front, 45 rear), the ride improved dramatically. The aspect ration of the 18's I have are 40 front and 35 rear.

The 911 has Michelin 4S and the Boxster Firestone 500s, all stock sizes except the Boxster fronts are slightly wider than stock. I can't directly compare them, but on the Cayenne, which came to me with Michelin run-flats, I replaced with standard Michelins and found a dramatically better ride. Handling is certainly not impaired.

Good to know! I've always been happy with Michelins, but as mentioned, I did read that my Continentals are slightly a less harsh ride than the Michelins that are available for my car. At the end of the day, probably a distinction without a difference between the two. I really wish I could find a taller sidewall available on a smaller wheel that would give me roughly the same diameter as what I have. Might be a impossible quest! I'll keep looking. Thanks, John!

I’ve had a 986 Boxster and now replaced it with a 997.2 On the Boxster I had Bilstein PSS9 coilovers installed & I loved them! Tuned to “euro spec” height age middle as suspension stiffness, it completely transformed the car & I loved it! But I never adjusted them Now after buying the 997 with a lot of miles - the first thing I wanted to tackle was the suspension. I thought I never adjusted my PSS9 coilovers, so just put non-adjustable B12 pro kit (aka B6/B8 with lowering springs) and…I absolutely hate it. It just made the car undriveable for the streets. Not only its way too low that I’m scraping everything, even during cornering but also it’s so bumpy that every single spot on the road hits my back over the seat. I’m about to get rid of them and replace with proper Ohlins coilovers set with DFV (dual-flow valves) to hopefully restore the ride quality

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Thanks for that input. Let us know how things turn out once the changes are done and all is sorted. By the way, welcome to Carpokes!

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Please do let me know where you land. Some of what you mentioned is Greek to me, but I am very interested to learn what struts / shocks make the car most compliant. I have no interest in lowering the car from stock, as that is already too low for the reasons you mentioned. I would have never guessed that the Bilstein B6 would be so rough, I just thought that it would be a tad stiffer than the stock B4 setup. I don't have PASM so just need a good, basic suspension that absorbs the road better than what I have now. Thanks...I appreciate your input! -Tom

I called Bilstein and explained the issues I was having with a horrible ride from the B6 dampers. They were of no help other than to say I should have bought the B4's which are the stock OE replacement. I've also read and viewed on YT quite a lot about suspensions, and have gleaned a bit of knowledge on dampers. The only coil-overs that were reported with a good ride on streets and even a possibly better ride than stock was the Ohlins R&T. But, the consensus is that unless you need to change the ride height or stiffness on a regular basis, then better to stick with the stock dampers and springs (B4's). And at $3300 for the set, the Ohlins are pricey and (to me) not worth the cost. I think the next time I need to buy new, I'll just go back to the stock B4's.

I’ve been having this suspension debate with myself as well! My ‘05 987S has nearly 120k miles and the suspension is definitely ready for a refresh. I do want to lower the car a bit, as it currently looks a bit Safari-esque, which is not my preference. IMG_0677.jpeg (2.5 MiB) Viewed 1525 times I was thinking about B6 + lowering springs, but it does seem like it will be too harsh. While I do AX the car regularly- that’s my main use for it- I drive about 100mi each way to events and comfort is still important. I guess I’ll either need to splurge for coilovers or go with B4 on stock springs and deal with the looks. I had KW v3 (and adjustable sway bars) on my 996 and the ride and height were perfect. As mentioned above, once I had the suspension set where I like it, I never touched it again. IMG_0676.jpeg (2.69 MiB) Viewed 1525 times

I bagged my old 911–absolutely love it!

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Track ready!! The Mobilgas horse is looking a bit anemic. He needs to be fed... MOBILMOBILGASVINTAGEGASSTATIONSCENEGIANTMURAL8X16NEWVERSIONWINDOWDETAILPROOF_1024x1024-1526352416.jpg (169.39 KiB) Viewed 1508 times

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Your 996 looks terrific! Did you have any issues scraping the front lip at that height? One of the YT vids I watched compared the KW V3 vs. the Ohlins R&T: and part 2: They thought the KW was very stiff for streets, while the Ohlins were much more compliant. At least that's how they set them up and these are interesting videos to watch. Thank you for your input!

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It was certainly easier to scrape the front lip, but I wouldn’t call it a deal breaker. For steep a driveway I just took it at an angle. I took that car many places, even down some dirt roads, and it was fine! The ability to adjust height is a great advantage of coil overs, and I could have gone higher (or lower) with the KWs. For ride quality, see if you can find someone local with the different setups so you can feel it for yourself. Comfort is very subjective. A firm ride is different than a harsh ride. I appreciated that the car just felt more planted overall after the suspension changes. Of course I sold that car in 2020 so the memories are getting fuzzier now… IMG_0678.jpeg (3.4 MiB) Viewed 1499 times

This is all new to me, so I appreciate your detail (2002 911, Carrera).

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Glad you found the site and welcome to Carpokes! Hopefully you'll find more nuggets and friendly, helpful people here.

I think you are on the right path. The shocks/struts need to be matched to the spring rate. I learned this the hard way when I installed performance dampers on my Subaru Forrester with stock springs. The harsh, jiggly ride even caused the tires to wear in an odd fashion. Found nice, progressive springs which solved the issue. Next it needs new tires.

Well, I broke down and bought some new 17" rims and tires in the name of science. I tried to capture the look of the 17's next to my 18's but the camera really doesn't tell the story very well. My photo skills are somewhat lacking I'm afraid. Anyway, long story short, I much prefer the 17's. The ride is significantly less jarring over joints in the roads and other acute bumps. I can notice zero difference in the handling otherwise. But the comfort is much improved and a lot less jarring to the car. Kind of a pricey experiment, but I'm glad I'm on the 17's now. Time will tell as to how they hold up, but I'd expect them to have about the same longevity as my 18's. P1010398.jpeg (803.06 KiB) Viewed 1238 times P1010395.jpeg (829.48 KiB) Viewed 1238 times For anybody interested, the OE tires are 235-40 R18 and 265-40 R18. The new tires are 225-50 R17 and 245-50 R17. So, a little bit narrower, but for the way I drive (and how most people drive) I can tell no difference in the handling. I realize this change is not for everybody - I may be the only person I know who prefers a taller sidewall! But low profile tires are not for me - I love the new setup!

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They'll also allow you to sneer a bit when/if you encounter potholes. Looks good!

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Love the Fuchs on that car, in that color. Really nice.

OP, I've had B6 dampers on prior cars (BMW M3s, not a 911) and based on my experience, the Sport dampers are very firm. See if you can find someone local to trade your B6s for stock dampers and I suspect you'll notice a big difference in ride and comfort. Also, if you have PASM, I highly recommend installing a DSC controller. There is a drastic improvement on ride and reduction of crashing over expansion joints and potholes with the DSC. Good luck!

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Thanks for the info! I don’t have PASM. If I don’t like the ride on these, I will go upscale with height adjustment and more adjustability. This car is mainly for AX, so it just needs to be comfortable enough for the drive to/from those events.

I have a 2011 Carerra with 17 inch Maxilite Fuchs. They were made for a 996 so require a 3mm spacer for front, otherwise correct offset. I was using a different set of 17’s but like these looks. Ride is never harsh, quieter but no 911 is quiet. Unless you track won’t no the difference in feel. 215/55 and 235/55 Only slightly higher which I appreciate as drive it everyday with no worries Tom

It's too bad you choose Bilsteins as your suspension. I've changed my wife's Infiniti G37 Sport to Bilstein coil-overs to lower the car and give it a better ride and regretted it from day 1. Bilsteins's are known to ride stiff and coil-overs are not better. Meant for the track and not today's street roads. However I changed my 1991 Acura NSX to KW coil-overs and couldn't believe how great the ride was even with track settings. It changed the whole behavior of the car in every way. Very compliant, great handling and extremely well made. Since they are made in Germany and they obviously know your car, I would move in that direction and find another buyer for those Bilstein's. Better pricing as well. Also going to smaller diameter rims and then ties to keep the circumference/diameter similar to the 18" rims would give you more sidewall rubber to help deal with those harsh road conditions. I know because I'm dropping down from my Panamera's 21" monster rims to 20" partly for a better/quieter ride but also because I can't find replacement 21" tires for my defective stock Pirelli's. Good luck. Al

OP, I bought my 996 Turbo with 100K miles and original suspension and 19" rims. The ride was horrible. I was embarrassed to take people for rides in the car. I swear I could run over a dime that was lying in the road and I'd feel it. I did a complete suspension refresh using all stock components (mostly Meyle and TRW) and installed BC Racing coilovers. Didn't want to lower the car, just wanted the adjust-ability of the firmness. With the coilovers, you can lower the car or raise it if you live in an area with really crappy roads. I've got my car at stock ride height and the coilovers about as soft as they'll go. It's fantastic! I don't track my car, so I had the alignment tech set up the specs for "normal" driving. The car still handles well and it handles bumps as well as can be expected. I don't cringe anymore when I hit bumps.

You guys must have some really crappy roads around you. I went with b6's and H&R lowering springs and can say even my wife has no problem with the ride. When I first got the car it came with 997 lobster forks on stock worn suspension. THAT was nearly undriveable. I first tried a set of 17" turbo twists, road better but lost the sharpness that I love about 911's. Changed the suspension, am now running18" Classic 2 wheels with Pilot Sports and am super happy.

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As someone who came from Bilstein B6 PASM to Ohlins R&T on a 997 Carrera, I agree with your conclusion that B4 will give you better road compliance (something that is often overlooked) whilst maintaining a stock ride-height. As you've learned, B6 is a bit more sportier and can be harsh for some that aren't used to it, especially without PASM functionality to actively change rebound/compression on the go. If you're unable to swap them for B4's, just drive the B6s for awhile. Eventually, they will become broken-in and get a little more road-compliant as you keep putting miles on them. However, they should last about 60K miles or even longer.

Appreciate the input! Since I went with the 17" tires, I have been very happy. The B6's are just fine with the 17's, where they were awful with the 18's. You wouldn't think the additional 1/2" +- of sidewall would make that much of a difference, but it really does. I don't expect to need new shocks for a long time, but if/when I do, I'll probably be looking at going to the B4's or consider the Ohilns. But honestly, for the money I think the B4's with my factory springs would be just perfect.