DIY Adjustable Tire Deflators 0-20 PSI

[Markos]

All:

I came up with a set of adjustable tire deflators. Cost is about $9.30 per deflator, or about $37 for a set. A savings of around $25 over a set of staun/oasis deflators. I knew it could be done easily with the right parts. It took a lot of searching to find a suitable pressure relief valve for a good price. In fact, that was the hardest part. There isn't a huge profit margin on deflators, so the cost savings isn't remarkable. If you are only looking for a couple, this could save you some cash. There are some down sides, listed in the preliminary observations below.

Parts:
Each deflator consists of a harbor freight tire chuck with a McMaster-Carr adjustable pressure relief valve threaded onto the end.

Harbor Freight Central Pneumatic Tire Chuck with Clip
Item: 42443
Price: $1.59 (on sale, link is to closest part match)

McMaster-Carr Brass Adjustable Vacuum/Pressure Relief Valve 1/4" NPT Male, 0-20 PSI
Part Number: 48935K25
Price: $7.70

Total cost was about $40 with tax and shipping. Note the price comparison above didn't include shipping for Staun/Oasis deflators.

Preliminary Observations:

• So easy a caveman could do it.
• In order to get the deflators to stop at the max pressure of 20 PSI, I had to remove the locking nut so I could tighten them more. The tighter you make them, the higher the cracking pressure.
• The deflators are loud, kinda like a kazoo or deflating balloon at first. It's kind of annoying, but this could also clue you in on when they are done. The noise continually decreases as the tire airs down.
• The deflators still trickle a very small amount when they should be finished. I'm attributing this to the metal-to-metal ball bearing valve not seating 100%.
• The Harbor Freight tire chucks seat well on the valve stem, with no leaks. The lever is somewhat clunky, forcing you to position them accordingly on some wheels.
• They air down pretty quickly. There is room to drill holes at the base of the deflators if you want more volume and faster flow. You could also bore out the tire chuck hole. The extra holes should help with the noise.
• If you had the correct 7.7mm tap, you could tap the end of the valve so it could screw directly on the schrader valve. You would need to insert something to depress the valve though.

I just threw these together tonight. I still need to run some more tests on these. If you are looking for a cheap deflator or two (or four), this may be the route for you.

Also, if you want an even lower profile deflator, you can try this instead. I haven't tested them, and they are just about as expensive as the adjustable:

Non-Adjustable Pressure Relief Vents:



Pics:
Parts:

Exploded View:

Tire Chuck air passage:

Valve air passage:

Completed Set:

 

[53guy]

Pretty slick. Try putting something to help seal the ball bearing, maybe a floating "o" ring or some lube of some sort (lithium grease maybe).

 

[sjd78]

I own a pair of staun tire deflators and although this is innovative I would spend the extra $20 on the stauns again, they work great! Good job though!

 

[karstic]

Good homebrew project.

Question for you, does your valve stems have the chromed metal collars on them?

 

[5-90]

Neatly handled!

The "continuing to leak" is something I'd only see as a problem if you were going to run with them still on the tyres - which would be quite silly. I'm assuming that the only real reason you made four of them is simply to air down all four corners at the same time, yes? Considering the air passage, you're probably just putting the last one on when it's about time to take the first one off, so that's not a big problem (as I see it.)

Bravo Zulu!

 

[KSXJ]

Do they require to be above a certain psi to work, I would think no. But if not, that is one plus over the stauns.

 

[Markos]

Do they require to be above a certain psi to work, I would think no. But if not, that is one plus over the stauns.

No they startup right away when you put them on the tire. The only way they wouldn't release any air is if the tires were already below your specified pressure.

The "continuing to leak" is something I'd only see as a problem if you were going to run with them still on the tyres - which would be quite silly. I'm assuming that the only real reason you made four of them is simply to air down all four corners at the same time, yes? Considering the air passage, you're probably just putting the last one on when it's about time to take the first one off, so that's not a big problem (as I see it.)

I agree about the air trickle issue. I'm also going to lube up the BB to see if that helps. I could try an airsoft pellet or something also. It's not a big deal at all. Also, this Sunday I'm going to drill six holes at the base of one of the deflators. One hole on each of the hexaganal sides. Proably 1/8th in diameter.

 

[Markos]

Update

The tire deflators work well. I used them on the trail about two weeks ago. A touch of bearing grease fixed the trickle issue. I drilled two small holes in one of the deflators, and that had no real effect on flow or noise. I decided to leave the others as-is. I also mentioned earlier that I removed the adjuster rings to get the deflators to stop at 20pi, instead of 15psi or less. I found that each deflator shut off anywhere between 19.5psi and 21psi. In order to get them perfect all around, I'd need to add the adjuster ring back, and use a lower psi.

After seeing the sidewalls at 20psi with 30x9.5 tires, I think I'm going to add the adjuster rings back, and run the tires at 15psi.

Overall, I'm really happy with the deflators. The noise isn't bad at all once you leave the garage and try them on the trail.

 

[Israel]

Great idea! Thanks for sharing.

 

[DougJ]

Cool beans. Love when someone is thinking outside the box!:cheers:

 

[ECKSJAY]

Update

The tire deflators work well. I used them on the trail about two weeks ago. A touch of bearing grease fixed the trickle issue. I drilled two small holes in one of the deflators, and that had no real effect on flow or noise. I decided to leave the others as-is. I also mentioned earlier that I removed the adjuster rings to get the deflators to stop at 20pi, instead of 15psi or less. I found that each deflator shut off anywhere between 19.5psi and 21psi. In order to get them perfect all around, I'd need to add the adjuster ring back, and use a lower psi.

After seeing the sidewalls at 20psi with 30x9.5 tires, I think I'm going to add the adjuster rings back, and run the tires at 15psi.

Overall, I'm really happy with the deflators. The noise isn't bad at all once you leave the garage and try them on the trail.

All that work for 15-20psi left in the tires?

:banghead:

 

[Markos]

All that work for 15-20psi left in the tires?

:banghead:

I don't get what you mean. I could set the deflators to 5psi if I wanted to. I chose 20psi on purpose. I thought that I outlined that in the original post, but I may have been unclear. They are more work that staun or oasis deflators, but I wouldn't really call screwing two parts together work...

 

[ECKSJAY]

I don't get what you mean. I could set the deflators to 5psi if I wanted to. I chose 20psi on purpose. I thought that I outlined that in the original post, but I may have been unclear. They are more work that staun or oasis deflators, but I wouldn't really call screwing two parts together work...

No, I meant why go to all the trouble of airing down for only 15-20psi? That's hardly what I'd call airing down...

 

[1996cc]

Yeah, that is my max street pressure. In fact, they are all at 9 right now.

 

[PornstaR]

No, I meant why go to all the trouble of airing down for only 15-20psi? That's hardly what I'd call airing down...

Hell i figured why spend the money..... he says 40bux for all that stuff??? I can air down faster and more accuratly with my ARB and it only cost me 20 and its a guage too............ 5psi baby !!!1 Mall crawling cant drop below 15psi DUHHHHHHHHHHH

 

[ECKSJAY]

Hell i figured why spend the money..... he says 40bux for all that stuff??? I can air down faster and more accuratly with my ARB and it only cost me 20 and its a guage too............ 5psi baby !!!1 Mall crawling cant drop below 15psi DUHHHHHHHHHHH

This type of deflator doesn't wear down cores.

 

[Markos]

Hell i figured why spend the money..... he says 40bux for all that stuff??? I can air down faster and more accuratly with my ARB and it only cost me 20 and its a guage too............ 5psi baby !!!1 Mall crawling cant drop below 15psi DUHHHHHHHHHHH

Actually the deflators are very accurate, I just took off the adjustor ring on mine to up the maximum pressure. I think that 15-20PSI is pretty good for a 30" tire anyway. I'm betting that they are just as fast as manually deflating 4 tires.

Also, you spent $20 (they cost $45 now btw) on one ARB EZ tire deflator. The delfators that I built cost $8 each.

 

[Madden350]

I think I will make one at work on monday. Thanks for the idea.

 

[Markos]

FYI - My original link to the valves is dead, but the part number hasn't changed.

Pressure Valve:
http://www.mcmaster.com/#catalog/117/470

 

[ECKSJAY]

http://www.amazon.com/CSI-C59000-Adjustable-Tire-Deflator/dp/B001IBQQFS