I just drove an 05 UL this morning and could not believe the ride was so stiff. It does have the 18" wheels so that is contributing to the ride as well as new Michelin tires, that could be contributing too. What actually surprised me was that no matter what setting i switched the "height" and "sport" controls, it drove and rode pretty much the same.
Is there a light or something on the display some place that would tell me what setting is the suspension at or if it's malfunctioning? I recently drove an 03 UL it felt a lot smoother. Is there any way I can verify that suspension works properly short of taking it to the shop?
Thanks!

 

ok, found this in the manual on-line.

"Height Hi"
The above message appears when the high mode in the
electronically modulated air suspension is selected.
However, if the system fails, the master warning light
comes on, a warning tone also sounds and the above
message appears.

I didn't notice the message in any mode I was switching it to. But I can't say I paid supper attention to the dash when i was driving. Maybe I need to revisit this again in a longer span of time.
Does anyone know what the largest tire I can put on this car. i.e. not the largest rim, but the overall diameter or radius whatever is considered to be the size. The lowest I'd go of course would be the 16" rim, but from there I am not sure what is the highest sidewall can be put on it without jeopardizing the handling too much.
Thanks!

 

I think you can get away with 9 inches wide for the fronts and 10 inches in the rear. I have 9 1/2/ 10 1/2 on mine and will require a rear shave and probably a roll up front. I think a 9fr/10r combo would be widest you could go, but I have 20's also, lol....no way am I going to be rolling 16's...

 

I think he wants to know how much tire/sidewall he can get as his main concern seems to be ride comfort. I recently put on oem 97ls wheels with 235/60/16 Michelin mxv4s. This is the next step up and slightly taller than the oem size of 225/60/16. It softened up my ride quite a bit and I haven't had any problems. Your tire size is going to depend on your wheel width and diameter you choose. You can find your current overall diameter wheel+tires for the 18" you have now to get an idea of what your options are by looking on tirerack. Tires of the same size will also vary from one manufacturer to the other. For reference my oem OAD was ~26.8" with Dunlop tires. My current setup has an OAD of 27.1" and my car is lowered with no problems. I don't have an UL so I can't comment on that aspect. hope that helps a little

 

Yes it does help hiimphilll,

thank you, this is the information I was looking for. I don't recall who said it either tirerack or 1010tires, but i remember them say +3% is the max deviance from original size without affecting the handling characteristics to make it unsafe. I am using that rule on almost all of my cars wherever I can get away with it. Drops the gas mileage a hair sometimes (most of the time) but to my back it's well worth it.

 

If you want the smoothest ride in a UL, stick with the OEM specs for wheels and tires. I think that's what the OP was concerned about.

 

i would have someone check to make sure the air susp was working properly. my car came with 17's for some reason but the ride was so so smooth, so maybe something is wrong with that one you drove.

 

I've driven 06 CL, 06 ML, and the 05 UL that I ended up buying. IMHO, the ride is very similar (coil vs. air) except the air feels more "floaty." Road feel is otherwise very similar. All vehicles had 18" OEM wheels with mid-line Bridgestone Turanza EL42 tires. This winter, I got a pair of Michelin Alpin PA3 performance snow tires that I'm running at 36psi just like my road tires. The Michelins are slightly noisier (being a snow tire), but have a softer ride over the bumps, probably due to softer rubber. If you want a softer ride at the sacrifice of cornering, the OEM 17's are an option.