Matching tank height for doubles?

[HenrikBP]

I know that when selecting a pair of tanks for doubles they should be "height matched" to avoid stress on tank bands and ultimately on the manifold. But how close is close enough?

I've been told that even a matched set of tanks from the distributor are never matched closer than about 1/8" difference in height.

I understand that making tanks is not precision machining and that it may be difficult to find two tanks of the exact same height, but for tanks without boots, what is acceptable?

Related question: I've been told that tanks vary mostly in the length of the neck, and that the tank "body" from top of shoulders to the bottom rarely varies by much. Is that correct, and if so, would measuring the neck length be a reliable way to determine if two tanks are height matched?

Thanks,

Henrik

 

[DA Aquamaster]

Just butt the tanks up against the wall base first and measure along the side to a ruler placed on the end of the neck. If you place the two intended tanks side by side and lay a yardstick across the top you can see how well they will relate to each other via the gap between the tall neck and the short one.

Personally, I have seen a great deal of differnece in shoulder and neck profile, but it is overall length that counts.

I think a 1/4" is about the max from an asthetic/not lean against the wall funny perspective. But people make too big a deal out of it. In the end differences in tank height does not really matter as if you drop the tanks from any height, they will most likely not land square anyway and anytime one tank at speed can still move then the other comes to a sudden halt, the isolator will bend - a 30-40 pound tank at several feet per second represents a lot of kinetic energy that must be absorbed or transferred.

Your best protection is to use wide, good quality, well reinforced bands and keep them tight to minimize any potential movement between tanks to prevent the isolator from getting stressed. The idea is for the energy to be transferred via the bands rather than transferred and partly absorbed by (ie bending) the manifold. And again, the big item in bend prevention is not to drop them in the first place.

 

[captain]

I wouldn't worry too much about it as long as the bands are strong and tight. Just lay the tanks on a flat surface while installing the bands so there is no strain on the manifold.

 

[HenrikBP]

Thanks guys - I see the point about quality bands kept tight. I own and like Highland bands, so I'll probably stick with those.

The perfectionist in me of course still wants the tanks *exactly* the same height

Henrik

 

[letterboy]

Just get them close enough and go buy yourself a new murse

 

[HenrikBP]

Just get them close enough and go buy yourself a new murse

What's wrong with the one I currently own/carry ...?

Henrik

 

[letterboy]

nothing, i just thought you would act like my ex-wife and have to go buy a new purse/shoes whenever something wasnt perfect

 

[Akimbo]

Thanks guys - I see the point about quality bands kept tight. I own and like Highland bands, so I'll probably stick with those.

The perfectionist in me of course still wants the tanks *exactly* the same height

Henrik

Just shim the tank boot. Find the shorter tank, pull the boot, drop a piece of plastic in the bottom the matches the height difference, and put the boot back on.

 

[HenrikBP]

Just shim the tank boot. Find the shorter tank, pull the boot, drop a piece of plastic in the bottom the matches the height difference, and put the boot back on.

Thanks, I've seen/heard that suggestion before. But for AL80 tanks I really don't want to add a boot to fix height issues, and for steel tanks I might want to remove the boots altogether to avoid trapped salt water causing corrosion.

Henrik

 

[kanonfodr]

Thanks, I've seen/heard that suggestion before. But for AL80 tanks I really don't want to add a boot to fix height issues, and for steel tanks I might want to remove the boots altogether to avoid trapped salt water causing corrosion.

Henrik

There is always Duct Tape.

Peace,
Greg