Topic: Mystery forces invlved?

[ballast]

I took the spare tire and carrier off the Jeep a few days ago.  I planned on dropping the weight to help me get over my nemesis, the Dames Pint Bridge.  I have only used 1 tank of gas since then but I have discovered....

1) I got 15mpg that tank vice the 12.5 to 13 I have been getting...
2) I maintained 68mph going up that sucker and wasn't over 3/4 throttle WITH the sides and back off.  I usually have to go WOT the entire way over that bridge in order to start at 80mph and end up at 55 at the top thats with the entire top ON the Jeep.

I understand the weight loss will help gain and maintain speed which will help fuel economy but come on, 60lbs. gains 1.5mpg???  I honestly doubt the spare tire and carrier added that much air resistance...

Anyone else experienced these mysterious forces.

[Jeffy]

Hard to say since you've only had one tank.  Daily variables could account for the change.

I don't think the spare would make a huge improvement unless you had it mounted on the roof.  The weights can't be more then 150lbs.  That would be equilivant to a 1-2hp increase I think.

To get a good idea if it did anything you'll have to go for a few weeks and get an average.  Although you better not get a flat.  

[JWJeeper94]

Absolutely priceless, I have done the same thing (removed my spare tire and holder) and have found that now these 5.0 mustangs have a hard time keeping up to my 4 bangin jeep. Just kidding obviously, but at this point in my new ownership if some one told me they had ice cream pouring out of the exhaust,I wouldn't necessarily think they were crazy.
I would think it possible that it helps,only because if I have tools or just anything of weight in my Jeep it makes a difference.And don't forget to buy your Jeep jacket, the one with the long sleves that tie in the back,it only comes in white but is an exclusive for Jeep owners !

Ballast ,if that works for you then more power to you brother!

[ballast]

UPDATE:  so far three fillups, 15mpg average on each.  

Prior to this I was averaging 13.5 to 12.5.

Installed a 4.0TB at end of the last tank and will soon have half a tank gone, looks to be maintaining 15mpg so far.

This week, full tuneup and hopefully figure out my damn tranny problem

[chrisfranklin]

All for Jeep weight loss...took my back seat out for the last four years(course, just bought another back seat off a "certain auction site"; its a bitch to pay for shipping on something like that! :)

Cool that the taking the spare off works for you.  I just have a big dent back their, so mine's probably staying on  

[Jeffy]

I did some reseatch on something similar a year ago.  I posted about it way back when too.  I removed my winch, spare, rear seat, tow hooks, winch plate, fairlead, rear bumper, front bumper and spare tire rack and apssenger side mirror off and only noticed a slight difference at best.  This was over 3 months.  I ended up putting most of the stuff back on.

Basically, you will gain 1hp for every 100lbs removed.

This one is really YMMV.  (I still have no rear bumper...)