Unsprung Wright and Ride Quality

So some of you may have seen some posts long ago in my RV thread. I am needing to do a tire rotation and am debating pulling the inserts out.

My wheels/tires are 216lb. Wheels are 62.6, tires are 95. Run flat insert is the rest. About 60 lbs.

Now either I Sawzall them out, or I try to pull them with my engine hoist. Either way it's sketchy. Sawzall is simple, cut the insert, pull it out. Engine hoist means putting the legs of the hoist on the tire, strap/chain around the insert and pull.

Worth loosing 60 lbs a corner?

I'm really worried most about ride, but a little Mpg wouldn't hurt either.

Engine hoist seems to be most common, but they all are working on HMMV wheels, look at the gap on that wheel/tire vs what I have using a pry bar. Seems WAY tighter and way more pucker factor on mine.

HMMV tire.

Mine

How heavy is the entire RV? The effect of unsprung weight on ride quality is related to the ratio of unsprung/sprung weight. If your current unsprung weight total is less than 10% you are unlikely to notice a change. Most particularly on a truck live axle the total mass of the axle is so great that the change will not be significant. Much more will be noticeable on the front, especially as you are sitting close to it. 

I don't have an RV or massive wheels/tires but wonder the same thing. I'm contemplating new wheels and the new ones would be about 6 lbs lighter per corner on my 1966 Chevelle so 24 lbs on a 3100 lb car. 
Is this something I'm likely to feel in the steering and suspension? I'd never heard any reference to 10% of the car weight. Did I understand that correctly?

In reply to TurnerX19 :

Total its 14500 ish. It was 14,240 when I weighed last, but a few additions have been made. 6200 on the front axle, 8040 rear.

Solid axle front and rear. Dana Super 60 front, and Setrling 110 rear.

In reply to 67LS1 :

The 10% number is from my own experience. I have never seen anyone really quantify it. I have read & studied the issue a lot for 50 years, and all of the written material I have found relates to cornering ability in bumpy conditions, not ride comfort. You will improve your bumpy cornering, but you might only be able to find it with a data acquisition system, not seat of the pants. The better your shock absorbers are the less likely you are to feel a difference too.

In reply to java230 :

In my first message I was presuming an unpowered front beam axle. With the Dana it is heavy enough I would keep the runflat inserts.

TurnerX19 said:

In reply to 67LS1 :

The 10% number is from my own experience. I have never seen anyone really quantify it. I have read & studied the issue a lot for 50 years, and all of the written material I have found relates to cornering ability in bumpy conditions, not ride comfort. You will improve your bumpy cornering, but you might only be able to find it with a data acquisition system, not seat of the pants. The better your shock absorbers are the less likely you are to feel a difference too.

Thanks. Yeah, I wasn't expecting life changing results but I have always heard lighter wheel/tire combos are better. I'm buying the new wheels because I like them but the lighter weight will be a bonus. It should also put my car under 3,100 lbs total. 

In reply to 67LS1 :

Get them because you like them. The weight savings would be a bonus. Added performance and safety even if you don't feel it. No downsides. Unless they are made of tin or vaporware.

TurnerX19 said:

In reply to java230 :

In my first message I was presuming an unpowered front beam axle. With the Dana it is heavy enough I would keep the runflat inserts.

Hmmm ok. I may still pull them just to see if there is a mpg savings. That's 240lbs of rotating weight to loose.

On the shock front, I got rather expensive shocks, and gave them the truck info for valving, but they made almost no difference in the seat of the pants feel. 

There is also the reduction of rotating mass, which will take less energy to accelerate. Maybe more important on the 3400# Malibu vs the 14k# RV, but still there. IIRC there's a rule of thumb that reducing rotating mass by X is equivalent to reducing non-rotating mass by 1.75X.

I have almost no data for the OP, but can say that switching to and from stock rotors and rotors on hats, which saves mayyyyybe 15 lb a corner, is noticeable in a big heavy e class Mercedes. As for the RV situation, it depends on the RV. Many of them are so close to max gross weight from the factory that taking around 250 lb off just about anywhere would be worth it just from that standpoint. Our old p30 chassis 26 footer was over max gross when we filled it, topped the water off, put our stuff in and climbed aboard. Yucky. 

In reply to Jay_W :

Interesting. If I could gain 1mpg I would be extatic, but I think wind drag is a lot more..... 

Im way under gross for mine, so that is a plus! But front axle is right about max load. Long wheel base loads the front end up.