# sidewall suspension



## sethwas (Apr 30, 2002)

Hey, 
This doesn't really affect me, but I was curious anyway: Nowadays low profile tires are getting stylish. As in many car manufacturers are putting them on their cars off the dealer lots, and lots of tire manufacturers are adding new lines, or modifying old lines, to accomodate the low profile demand. 
I was reading that many of the car manufacturers that put the low profile tires on their cars change their suspension settings to 'better accomodate' the low profiles. They aren't necesarily stiffening the suspension since the short sidewall makes for a stiffer ride, and they aren't softening the suspension since those tires are on the 'sportier' cars, although some big sedans are going the low profile route as well. 
The manufacturers say that they are adjusting their suspension specs to make the car 'ride' better. Give the car the same feel but better performance with the lower sidewalls. 
So my question is, do any of these things matter for our bolt on kits for the sentras. I understand if you have AGX's that you can tailor the dampening. But lets say you are running a non-adjustable shock absorber. What kind of ride difference would one expect with a taller sidewall? 
Now here's the rub. Taller sidewalls do not make mushier rides or worse handleing. Most, if not all, full fledge race cars (I can only think of touring cars and rally cars on tarmac as an exception) run with standard sidewalls. They are just stiff. 
I know this is a fairly open ended question since the possibilities are endless as far as tire, shock, spring, and dimensions are concerned. But if I were to ask this all in one question: 
Does it make sense with an aftermarket suspension to get 14-16 inch wheels with the best tires money can buy in the proper size (with a sidewall) or just go the low profile route and throw on any rubber (rim weight being a constant)? Looks are not important. And I understand a sidewall will make for longer rim life. Which will have the better dynamics? 

Seth


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## barnoun (May 7, 2002)

Most of the time the best performing tire will have a lower profile. As for crappy low profile tires...they're still crappy.


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## sethwas (Apr 30, 2002)

Well,
To sum:
With a modified suspension (for handleing not looks) what is the difference if I run low profile or not. Sure the sidewall will flex on a larger profile, but what if I get stiff sidewall tires? Is the ride better on low profile mod suspension, or large profile mod suspension. 
I ask this because some cars suspensions are dialed for use with a low profile tire. Is there a drawback (in comfort) for using the large or low profile. (other than hunting for/tracing cracks, and less compliance for rocks, potholes, etc.). 

Seth


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## barnoun (May 7, 2002)

The larger sidewall tire provides a smoother ride since it serves more as a cushion between the road and passengers, while lower sidewall tires transmit more "impacts" I guess I can say. As for the effects on a modified handling suspension, the tire with a higher sidewall will provide a smoother ride at the expense of increased understeer, slower turn-in, and less direct feel of the road. Oh yeah, low profile tires are any tires with a 50 or less on the sidewall aspect ratio. 55 or higher isn't condered low profile. For example: 195/50/15 = low profile, while 195/65/15 is not low profile.


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## sethwas (Apr 30, 2002)

barnoun said:


> The larger sidewall tire provides a smoother ride since it serves more as a cushion between the road and passengers, while lower sidewall tires transmit more "impacts" I guess I can say. As for the effects on a modified handling suspension, the tire with a higher sidewall will provide a smoother ride


Correct. This I know...



> at the expense of increased understeer, slower turn-in, and less direct feel of the road.


Ok, this is along the lines of what I wanted to hear. But my question on rubber quality stands. I don't see how the low profile gives you an advantage on higher quality rubber. 
My point in all this is that I'm trying to get the best handling and ride combo. I am not quite sure on the evaluative dynamics involved in the design of our aftermarket systems. My logic is that I would get aftermarket springs and shocks, and simply top of the line tires on factory, or near factory (+2 inches MAX) wheel diameter. 
I want the 'smoother ride' as stated above, but I don't want any 'drawbacks'. I am a man of compromise, and I'm not building an autocrosser, so I don't _really_ care if there are subtle discrepancies.

Seth

P.S. Just for the record, for now, I'm running the NX2000 14" alloys, on Pirelli HP rubber. 3 years ago when I got the car I had the 14" steelies and factory rubber, 3 months later I got the Pirelli's and the ride/handling difference was very noticeable. I got the alloys 3 months ago, and the ride difference was nil, but the steering feel changed. Only recently have I been hunting for a suspension upgrade. Both because the car has aged, and so have I.


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## barnoun (May 7, 2002)

sethwas said:


> *
> ...Ok, this is along the lines of what I wanted to hear. But my question on rubber quality stands. I don't see how the low profile gives you an advantage on higher quality rubber.
> My point in all this is that I'm trying to get the best handling and ride combo. I am not quite sure on the evaluative dynamics involved in the design of our aftermarket systems. My logic is that I would get aftermarket springs and shocks, and simply top of the line tires on factory, or near factory (+2 inches MAX) wheel diameter.
> I want the 'smoother ride' as stated above, but I don't want any 'drawbacks'. I am a man of compromise, and I'm not building an autocrosser, so I don't really care if there are subtle discrepancies...
> *


Only other reason I can think of on why the low profile tire gives better handling is because the sidewall delfects less than the higher profile tire under cornering. The only exception I know of(big sidewall with better handling) are R compound tires. They're available in stock sizes with large sidewalls yet provide increased handling ability because of their super stiff sidewalls and sticky rubber. You know what though, I doubt they provide a comfortable ride(stiff sidewalls).

Since you want to retain comfort, it sounds like you already have a good plan. Upgrading the suspension will lessen body roll and help the car transition quicker, while keeping "squishy" tires will isolate the car from the road, providing the smoother ride. If you ever want to autocross or something similar, you'll already have the suspension setup and switching tires won't be a big deal.


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## sethwas (Apr 30, 2002)

Yup,
Thanks.

Seth


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