scout

I currently have 17" Bridgestone's on my GS430 and everytime my 4 year old son rides in the back seat he says he is getting car sick. Are there any other 17" tires I could put on which would give a smoother ride. I have about 13K on the tires.

Also do the 16" rims/tires give a much smoother ride?

///MDex

Before you go shopping for new meats, make sure your tire pressure is correct, all the way around for that matter. Over inflated tires can really pass along road irregularities.

Heck, he just may be prone to car sickness. j/k.

HTH

mooretorque

Considering how the GS wallows around on 16s, I'm not sure he'd find them any improvement, either. Do check inflations, tho.

RON430

scout - Have you done anything else to your GS? Regardless of tire size, the stock suspension promotes a float that can generate to a hobby horsing in the back seat. Mine still does it a bit but bilsteins took the vast majority of it out. To me, the softness made a much more unsettling ride than the slightly stiffer one with the bilsteins. I am not prone to carsickness and have been around cars for a long time but the stock suspension just made me a bit queasy on some of the washboard we get for freeways around here. For the real men out there, I have noticed that the motion is a lot more noticeable in the back seat than the front. If you do some searching on tires, there have been some discussions on this before and dropping that profile definitely makes a harsher ride. I have pretty much decided to stick with the 16s after reading some other experiences although I will most likely go to 245/50-16 when the time is right for the increased contact patch. Just curious, does your son get queasy in the front seat? If he is OK in the front, my guess would be that the soft stock suspension is doing him in more than any harshness from the tires.

bitkahuna

iTrader: (20)

Use dramamine.

But seriously... The 16's are DEFINITELY a smoother ride than the 17s, but there's a lot of sidewall flex on cornering, although if you drive like an old lady this won't be an issue.

You might consider using 245/45/17s instead of the stock 235/45/17s as this will be a bit taller, providing a slightly smoother ride. Lots of smoother/quieter 17" tires than the Potenzas, like Yokohama dBs, or Toyo Proxes FZ4s (T-1s are smooth too but more aggressive and probably more noisy).

Others have mentioned pressure - def. a good idea to get that right with low profile tires. Even though the dealer might leave 30lbs in them, I'd put 34 or thereabouts. Might seem counter-intuitive to get a smoother ride out of higher pressure, but with low pressure you actually feel the bumps hitting the RIM more I believe.

RON430

Lot you can do with tires, even within the same brand. For the better tires, going from an H to a V rating gets you a softer rubber compound and stiffer sidewall (that obviously cuts down flexing) which will make a harsher ride, once again, if this is what's causing your son's queasiness. I guess I'll stay with the little old ladies. Been a long time since a harsh ride made me feel like I had a good handling car. Too much time in bimmers, handling and harsh ride are definitely not connected. Hope this makes scout's 4 year old feel better, still think under dampening is more of an issue than sidewall stiffness.

scout

I check my tire pressure regularly so I know that is not the problem.

Ron - my setup is completely stock. He always rides in the back seat so I can't compare how the ride is in the front.

He normally rides in my wife's RX300 and has no problems so I know there is something going on with my GS.

I'll probably look at what Bit said and get some different 17" tires. I really like the look of the 17" rims and would only go to the 16" as a last resort.

Thanks for your suggestions.

RON430

scout - Regardless of what has been printed, I don't think I would recommend going to the 16s if you have the 17s. Just don't think that concentrating on the tires alone will solve the problem. Good luck.

bitkahuna

iTrader: (20)

Ron, you're probably right. The stock suspension floats up and down a whole bunch, so that's probably a big factor. L-Tuned setup is a WHOLE bunch better.

RON430

bitkahuna - Those of us who are used to firmer (but not harsh) rides are probably very aware of what I was talking about. I can't believe I put the bilsteins on a car with 1500 miles or so but the freeway float was not just undesirable but I felt slightly unsafe and definitely put a knot in my stomach going over some big dips. Just wish I could figure out some sort of test scout could do before he gets serious on the new tires. I have this feeling that scout's unfortunate 4 year old is the unintended victim of a too soft suspension and not stiff tires. This might sound counter intuitive but I much prefer the ride with the bilsteins even with the stock springs. Stabilizer bars go on when it gets a little warmer and I think it will make for a safe, pleasant ride (at least to me), that is going to have higher cornering limits. But I am sympathetic to those who find the stock suspension stomach turning.

mooretorque

On a slightly unrelated note (other than RON mentioned it), I would NOT put a 4 year old in the front seat of our GS. The airbags are not "smart" and deployment into even a small adult much less a child, would be disastrous.

scout, the good news in all this is that you now should have carte blanche from your wife to L-Tune your suspension. You may certainly tell her that your on-line physician (me) recommended it. And all of the CL gurus have also blessed the union. What's not to like?

RON430

Can't get them out of their car seats. Here in Cal we just increased the weight for use of the child seats. Just can't figure out a good experiment to see what might be the cause. Still think that motion in the back seat with the stock suspension is to blame. Last town car I rented just about got me to hurl while driving it. Firm suspensions can bring their own problems but for a stocker, I think it is those poorly damped motions that might be to blame.

bitkahuna

iTrader: (20)

Ron - I agree.

QBranchCars

My 6 and 3 year-olds have been riding in the back for almost a couple of years with no problems. I guess the Bilsteins, and now the Teins, and 18" wheels are to their liking.

Well, one interesting note is when my car was fully stock riding on 16" wheels, my mother got car sick while driving my GS! Now, she's very sensitive, and cannot ride as a passenger in a car without being the driver, but that was the first time I recall she got sick driving. And no, she has not driven it since, but it would be an interesting comparison.

RON430

Don't know if we are flogging this to death but the original thread was that a possible harsh ride was making the carsickness. I think this can be the case but in my experience, a too soft suspension is a far greater suspect. Personally, I may get to the point of not liking a too stiff ride because of harshness but it doesn't get the stomach churning like those poorly damped oscillations (like 101 around candlestick - qbranch) that just get everythink oscillating. Appreciate the comments, still wish we could come up with some test for scout before he buys tires. Sounds like finding somebody with some mods to the suspension who is willing to take a 4 year old out might be the best solution. At least scout would know. Hope Lexus is listening. There are a lot of Americans (why do they think just Europeans like firmer suspensions) that find soft dampening sickening (literally) rather than luxurious.