[cadman50]

Man, I live in an area that they stuck manhole covers in the travel lanes but not at regular intervals or in the same side of the travel lanes. And most of them are sunk down 1,2,3 or more inches. So when I hit one that is deeper, it seems like when the rear wheels hit it, it feels like I'm damaging the tire or wheel or suspension. I purchased the DHP thinking it would smooth out some of these but sort of disappointed it doesn't. My previous FX35 was even worse so at least i'm getting a step up. I'm wondering if the heavy impact feeling is more the run flat tires having a stiffer sidewall. It was my understanding that when the front wheel hits a bump, the sensor translates that to the cpu and adjusts the rear shock accordingly but maybe I have an ancient cpu I have to admit though that the ride is very nice otherwise with the DHP and quite happy I got it. Has anyone that changed over tires to non-runflats noticed a dramatic improvement of the ride? I'm constantly looking over the entire road surface as I drive for potholes and manhole covers and it takes the fun out of drivng sometimes. it's the one time when I'm adjusting something with the I-drive that I hit one of these.

[clivem2]

The only redeeming factor of RFTs is that you don't get bulges in the sidewalls when they are given them this sort of treatment. I had to replace several non-RFTs due to potholes disguised as puddles.

[tank531]

What size rims are you running on? The RFT's, sport suspension and 19" rims will make the ride hasher - no dispute. The only question is personal taste - are you happy with the trade of for improved looks and faster cornering, albeit on the limit cornering?

[cadman50]

Originally Posted by tank531

What size rims are you running on? The RFT's, sport suspension and 19" rims will make the ride hasher - no dispute. The only question is personal taste - are you happy with the trade of for improved looks and faster cornering, albeit on the limit cornering?

No doubt! I have a 35i with SAP and DHP. Don't get me wrong i like the ride EXCEPT when I hit those MH covers. Fortunately I drive the same 7 miles to work every day and I know where every one of those bastards are.

[MetaX]

I'd imagine that the larger wheel diameters (including the tire of course) of the FX35 would do a much better job with potholes than the X3?

[paul386]

Originally Posted by cadman50

Man, I live in an area that they stuck manhole covers in the travel lanes but not at regular intervals or in the same side of the travel lanes. And most of them are sunk down 1,2,3 or more inches. So when I hit one that is deeper, it seems like when the rear wheels hit it, it feels like I'm damaging the tire or wheel or suspension. I purchased the DHP thinking it would smooth out some of these but sort of disappointed it doesn't. My previous FX35 was even worse so at least i'm getting a step up. I'm wondering if the heavy impact feeling is more the run flat tires having a stiffer sidewall. It was my understanding that when the front wheel hits a bump, the sensor translates that to the cpu and adjusts the rear shock accordingly but maybe I have an ancient cpu I have to admit though that the ride is very nice otherwise with the DHP and quite happy I got it. Has anyone that changed over tires to non-runflats noticed a dramatic improvement of the ride? I'm constantly looking over the entire road surface as I drive for potholes and manhole covers and it takes the fun out of drivng sometimes. it's the one time when I'm adjusting something with the I-drive that I hit one of these.

The dampers are supposed to adjust for road conditions but there is no disclosure or documentation on how this works. I'm skeptical of its ability to react that quickly (to a single input like a pot hole)... the performance of the control system and valves / actuators would be very high (and very expensive).

Even if it was able to react - there is only so much it can do. Damper control of... maybe +/-30%... isn't going to make a pot hole feel any nicer.

[cadman50]

Originally Posted by MetaX

I'd imagine that the larger wheel diameters (including the tire of course) of the FX35 would do a much better job with potholes than the X3?

No way! the FX35 is built on the same platform as the Nissan 370Z. And I got the sport suspension with 20" tires (265/50-20). I felt every pebble in the road. The X3's ride is much more compliant. So far I've mainly driven in Normal mode but will be in Sport mode pretty soon as my breakin period is just about over. Then I'll see just how compliant this suspension is.

[cadman50]

Originally Posted by paul386

The dampers are supposed to adjust for road conditions but there is no disclosure or documentation on how this works. I'm skeptical of its ability to react that quickly (to a single input like a pot hole)... the performance of the control system and valves / actuators would be very high (and very expensive).

Even if it was able to react - there is only so much it can do. Damper control of... maybe +/-30%... isn't going to make a pot hole feel any nicer.

I was going to ask that same question about how the DHP works; more specifically the active suspension. I think I read somewhere on the forum that had a good explanation about it. How do you know it's working? I had to look at my shocks to see if they were wired to make sure I got the DHP.