What did you do to / for your E53 today??

[srmmmm]

Originally Posted by semcoinc

On my trip I used the miles traveled and MPG shown in the iBus app to estimate my fuel consumed. In all but one fuel stop this proved to be workable. One fuel stop I took 23.75 gallons for a presumably 24 gallon tank

Not to worry. I've put as much as 24.1 gallons in mine.


2002 X5 3.0 378,500 miles
2014 428i 67,700 miles


2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles


1970 Firebird Under restoration

[bcredliner]

Originally Posted by oldskewel

If you want to really know then, a free body diagram will show it clearly, but ...

Anything you're doing with "flex" is primarily creating a torque which is offset by the pair of crossbars which must create a counteracting couple. The 40-30-30 ratios you're talking about may be true, but what matters is the net actual forces on the bars, not the ratios.

Here's one way to think about it:
1. consider the case where there is no rear support, just that of the crossbars. Assuming the load is centered, it's pretty easy to see that the weight will be split equally and carried by each crossbar.

2. then consider the case where the beams weigh nothing at all, and you jack up that rear support, creating internal stress in the beam, countered by forces on the crossbars (since the beams are strapped down). In this case, the front bar will push upward on the beam, and the rear bar will pull it downward, with the couple providing a torque exactly offsetting that from the rear support. The amplification factor will be greater based on ratio of overall beam length vs. the spacing of the bars.

3. now consider the case you actually have, where there is a rear support, and the beam is not massless - a combination of 1 and 2 above. Since all this analysis is linear, the answer in this case is a sum (linear superposition) of those two other cases. So whatever you had in case 1, you can just add the answer from case 2 to it.

4. OK? If so, since the answer from 2 showed that the front bar had an upward force on the beam, then this means that the force on the beam applied by the front bar (so the force on the front crossbar is this amount, downwards) will be greater than it was with no rear support. So although the pre-loading from the rear beam may be decreasing the stress on the rear crossbar (if the forces and distances are in the right range), it is guaranteed to increase the loading on the front crossbar. And of course that is not good. You just need things to fail in one spot to cause problems.

Another way to possibly help understand it - consider if you had a single crossbar supporting things at the center of the beams, and a pin-joint trying to push up on the rear end. Think that all the way through. Then consider two crossbars closely spaced, etc. - that will change things slightly, but not materially. In this extreme case (very closely spaced bars), the forces on the bars needed to create the counter-acting torque will vastly exceed the net upward force due to the rear support.

As long as the bar spacing is a lot shorter than the overall beam length, the force increase due to the counter-acting torque will exceed any reduction in force due to the rear support.

Main thing is to not think you have any extra rack load capacity due to something you're doing just on the back end like that, with something that is basically a pin-joint. That could lead to problems.

If still not convinced, it would be a lot easier to just do the calcs vs. trying to explain it intuitively, so feel free to provide the dimensions, weight, and rear support load (estimates of course are perfectly useful) and I'll get hard numbers.

What I understand is he got where he wanted to go, wood didn't fall off on the way, and there was no damage. I wouldn't have the nerve to even try. My input is Good Job!

[andrewwynn]

In addition, the load was about double the rating of the roof rack so I went very slow I had my hand on the load though the sun roof to judge how much it was moving and went only 2 miles.

The ladder, however I needed that secure it was going 80 miles much of that at 80 nph

Also: Demonstrated a possibility that can be done.

[semcoinc]

Originally Posted by srmmmm

Not to worry. I've put as much as 24.1 gallons in mine.


2002 X5 3.0 378,500 miles
2014 428i 67,700 miles


2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles


1970 Firebird Under restoration

Did you push it in?

Mike

[Fifty150hs]

Originally Posted by srmmmm

Not to worry. I've put as much as 24.1 gallons in mine.


2002 X5 3.0 378,500 miles
2014 428i 67,700 miles


2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles


1970 Firebird Under restoration

I've done the same. Almost every car or truck I've owned would take more gas than what the tank supposedly held.

[andrewwynn]

capacity of e53 is I believe 92L = 24.3G. The tank sensors do not register either the top 10L nor the bottom 3.6L


The low fuel comes on at a registered 8L on the 6 cyl and 10L on the 8 cyl. When the gauge reads 0.0 gal = 0 distance to empty the tank has 3.6L of fuel.

[snik]

Originally Posted by andrewwynn

capacity of e53 is I believe 92L = 24.3G. The tank sensors do not register either the top 10L nor the bottom 3.6L


The low fuel comes on at a registered 8L on the 6 cyl and 10L on the 8 cyl. When the gauge reads 0.0 gal = 0 distance to empty the tank has 3.6L of fuel.

What? For real?

Sent from my Pixel 3 using Tapatalk

[Maruzo]

Originally Posted by andrewwynn

capacity of e53 is I believe 92L = 24.3G. The tank sensors do not register either the top 10L nor the bottom 3.6L


The low fuel comes on at a registered 8L on the 6 cyl and 10L on the 8 cyl. When the gauge reads 0.0 gal = 0 distance to empty the tank has 3.6L of fuel.

Great info. Thanks!

The red light on mine (4.6is) went up yesterday, so that means I have I 10Litre/2.6 gallons left in the tank?

I refilled 21 gallons this morning to top it off. That adds up to about 24 gallons.

As a side note, 91 octane is 3.25/ gallons today in Los Angeles!

[SpookX5]

Washed it and put on some tire shine

[EODguy]

Looking great!

Sent from my SM-A730F using Tapatalk