I had stock rims with Continental Sport Contact 3 for my 350z. Front tires (225/45/18) rear tires(245/45/18). I change this tire which i thought it will be comfort and quiet ride compare to stock tires that recommend by tire dealers n thru studies.
It seems that the car result to be fine at a moderate speed below 130km/h, but when it reaches above that speed, leads to a harsh n bumpy ride, feel insecure when the car is cruisin at that speed.
Do u guys experience this matter in ur car? was wonderin was it the tire profile or stock rims spec or any other alternative that cause this problem? And, does aftermarket rims with wider offset compare to stock tires lead to a bumpy ride at fast speed (after 130km/h)?

 

What is your air pressure? It's sounds like it's either too high, or it was too low on your old ones. I have seen a little difference in different brands, but if they are the same size, they shouldn't be drastically different in ride quality. Also, did you have an alignment done when you got your new tires?

 

tire pressure is 30-31 psi with conti sport contact 3 recommended for tropical weather country. alignment has been done after tire has changed n using these tires for about 4 months. are u using stock tire? will it helps to have a better the comfort ride after changin to wider or bigger rims/tires?

thanks for ur concern.

 

I think I'd bump the pressure up a bit. I usually run 35. I'm running stock size, but bought Falken ZE912s the last time. I really like the ride, plus they're great in rain and have a 40K warranty.
If you get bigger rims, which in turn require lower profile tires, you'll have an even bumpier/harsher ride.

 

the major problem is that continental tires is still a harsh ride but better than stock tires(bridgestone). will it helps to have a better the comfort ride after changin to wider or bigger rims/tires?

 

well, i thought of goin for wider rims, as i see some 350z members here are using wider and bigger rims such 18" 9.5+22x 10.5+22 and 19" 9.5+22 x10.5+22. whereas the handling n stability of the car would be better as compare to my current setup, correct if im wrong.

 

Some tires offer a more comfortable ride than others. Some less comfortable.

Car feels insecure at high speeds? Steering? Front end? Stability is effected by front end alignment. And alignment is always a compromise between quick handling and straight line stability.

 

yea, the car feels insecure at high speed at straight road. it cause the car bumpin at high speed. Its not cos the road, cos im cruisin at highway, which is freeway as name in US (if im wrong). steering is fine.

 

Hmmm. At that speed (80 mph/130 kmph) the Z should be as solid as a rock - whatever tires you have. Maybe you should have the alignment double checked?

 

I ran over (SUV swerved) some lane divider domes (Porsche folk call them 'elephant turds') the other day and dinged the rims on the right side. I'm having them straightened/trued and painted ('06 touring roadster) and putting on a set of Kuhmo ASX all around (at 22.7K mi). I could have gotten another 5K if I had lowered the pressure in the rears a tad on the original Bridgestones. I'm expecting the Kuhmos to last longer and be better in the rain. Anyone have experiance with these tires?
Thanks.. Bill Beamon

 

Stay away from Kuhmos they are garbage!!!!! Had them on an older car of mine. The sidewalls are garbage and bubble very easily

 

Your tire setup (225/45-18” front and 245/45-18” rear) on stock rims should feel very secure at 80 mph (and even at much greater speed). Here are some things to check:

• You said you are running 31 psi on the tires. That’s too low. Raise the psi to 35.
• As David mentions, alignment is crucial if for no other reason than excessive wear.
• If the tires are not balanced correctly; the faster you go, the worse it feels.
• And, it’s possible you have a single bad tire which can really mess-up your drive.

--Spike

 

thanks for the advice guys, i will take my car for checkup to see whether the alignment n tire is balance. hope it may solve the problem.

 

BTW if you want a more comfortable ride look at the Pirelli P-Zero.

https://my350z.com/forum/showthread....ighlight=tires

 

Get a Cadillac.

 

drop off my car at the workshop to sent the car for alignment n balancing. i can't be there cos i have other appointments. the service technician told me that they had adjust the front and rear camber (stock kit) and align the car. im not sure what number degree did they adjust as their boss took to his other shop to inspect the car but the car feels comfort at 130km/h, is not bumpy as before, and could even handle cornerin at high speed than before, feels the car stick to ground well. I will get back to the shop to get more info about the adjustment camber and get u guys updated. by the way, do u know what is "power" switch button beside the heater seat button? what does it do? my car is version T.

 

well, i jus spoke to the owner, he said that he had adjust the stock camber to the 80-90 degree setup, but im not sure whether is it positive/negative. could it be any wear and tear in the long run if stock camber is adjust to that degree as mentioned above although it remain a comfort ride.