20 inch rim on rear GM A-body= bad ride??

[BaddestBuick]

Ive heard that a 20 inch wheel on the back of a GM A-body would not have a good smooth ride is this true what about if i put a full air ride suspension will that solve the problem?? I was thinking about getting 18inch in the front and 20inch in the back with a 295 tire on back - but the last thing i want is a bad ride...any info on this ??

[79T/Aman]

well and A-body or any other vehicle for that matter will not ride smooth with those wheels

[BaddestBuick]

ah that sucks. then why do so many people on here have 20's or bigger on their cars it must not be that bad of a ride??..

[dipren443]

Look at it this way, it is not just a function of the wheel size, but how much tire you can fit with the wheel size. You cannot fit much sidewall with a 20" wheel. The tire is a functional part of the suspension. The more sidewall, the more the tire helps absorb bumps.

[Norm Peterson]

then why do so many people on here have 20's or bigger on their cars it must not be that bad of a ride??..How many of those cars do you suppose are true daily-drivers? For a car whose primary mission is show (or timed competition, for that matter), ride quality lies somewhere between "not a priority" and "not a consideration at all". In addition, I think you'd find that the ride would have to be flat-out horrible before most people would start posting complaints about their own choices.


Norm

[MonzaRacer]

Ultra low profile tires do ride very rough, any tire less than 45 series will ride very rough.
With stiff springs it gets a little worse.
But if you install air ride the suspension the ride and handling will go up expotentially if properly setup.
While the ride firms up you get used to it especially if you like a car handling like its set up for road racing.
BUT 20s are not condusive to handling like 17s or 18s.
They can be worked into a handling car but I have seen way to many use them and the tires just dont have the flexibility to live on track as well as the 17s or 18s and certain 19s.
Honestly I have always felt all low pro 20s look dorky on bigger cars,,, too short of side walls.

[BaddestBuick]

i dont think this one looks dorky, it looks amazing, 20's in the back and 18's on front i think i just got to excited and wanted the same for my car. too bad they dont make 19 inch smoothies ill probably end up getting the 18's even though i want the 20's in the back


<a href="http://photobucket.com" target="_blank"><img src="http://i23.photobucket.com/albums/b375/ImNelson/fdf.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>

[Apogee]

OE C6 Corvettes are 19" rears with a 35 series tire (runflat no less) and they ride pretty nice IMO. Suspension setup is important and any additional sidewall you add to the equation can add a little compliance and forgiveness to the system.

I like the staggered look on A-bodies. I've seen a few 18/19 combos that were very clean and daily drivers as well.

[michael6372]

i had 18/20 combo on my 63 nova. i also had air ride. the ride in my car was actually pretty good. i agree that the shorter sidewalls of 20s will make the ride a little harsh but the air ride setup more than made up for it. i used my car on a regular basis with no problems. it's your car, if you want 18/20s on it, put them on. if you have the room , they do make alot of different tire sizes for 20 inch wheel. just my .02.

[ScotI]

The key is keeping the sidewall height equal to what the OE manufacturers offer. A 4" sidewall height is the same for a 17, 18, or 20" wheel. Therefore a 295/40-20 will ride no worse than a 275/40-17 using the same suspenions. Just don't expect them to handle equally . . ..... more wheel/tire = more weight to manuever.

The question is can you fit a 29" tall tire? If so, the 295/40-20 will work fine on an everyday car. I've used them on the rear of my 74 truck since '03 w/o issue.

The car in the photobucket pic looks like it has 275/35-20's on the rear (est 3.7X" sidewall height) which are a little short for the daily grind. Expect to replace a rim @ least once in the life-span of the tires.

[Norm Peterson]

I'm not sure I follow those 20" vs 17" sizes as far as comparison is concerned. But I'd expect a 20" tire to have a slightly greater load capacity than a same width same profile 17 and, by implication, a slightly greater vertical spring rate at any given inflation pressure. I don't know what the overall effect might be if you reduced the 20" inflation to match the load at whatever 17" tire inflation you'd be comparing against though.

A separate effect is that the greater mass affects suspension rebound frequency and the optimum damping for that, so it isn't quite an even swap as far as overall ride quality is concerned. Given that there be no changes to the suspension or attempts to maintain the ratios of sprung to unsprung masses.


Norm

[ScotI]

I'm not sure I follow those 20" vs 17" sizes as far as comparison is concerned. But I'd expect a 20" tire to have a slightly greater load capacity than a same width same profile 17 and, by implication, a slightly greater vertical spring rate at any given inflation pressure. I don't know what the overall effect might be if you reduced the 20" inflation to match the load at whatever 17" tire inflation you'd be comparing against though.

A separate effect is that the greater mass affects suspension rebound frequency and the optimum damping for that, so it isn't quite an even swap as far as overall ride quality is concerned. Given that there be no changes to the suspension or attempts to maintain the ratios of sprung to unsprung masses.


Norm
The size comparison was meant to highlight the fact that regardless of wheel diameter, a 275/40 has the same sidewall height. There are several factors that determine ride quality; sidewall height is one of them.