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doc47

Inner tube question: Nuts!

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doc47

Having dealt with tubeless tires I'm now riding an F650 which has spoke wheels and inner tubes. Hence, the following:

 

Some inner tubes come with two nuts on the stem. One is relatively loose and the inner one tightened down. So, does the inner one (the one closest to the tube) go on the inside or the outside of the rim?

And, does the one on the outside get tightened, merely snugged down, or -- some people say -- used to lock the cap?

 

Dirtrider, I'd bet you know the answer!

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dirtrider

Afternoon doc47

 

As a rule they both go on the outside (if you even use them).

 

I you always run higher pressures in the tube then you can run them down tight to the rim. If you run lower air pressure then back them up to just under the air cap (not touching the cap though) then lock them together.

 

Reason being: if low air pressure allows the tire to spin on the rim slightly you don't want that to rip the stem off of the inner tube. With the nuts not tight on the rim you should see the stem lean at an angle if the tire spins on the rim.

 

Personally I don't even use the nuts, I use a short tight fitting piece of hose to sort of seal the valve stem area from dirt & junk entry. At times I run real low air pressure & I would rather have the stem lean or even pull into the rim than get ripped off & leave the tube non repairable out on a remote trail somewhere.

 

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doc47

Do you use rim locks?

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dirtrider

 

Afternoon doc47

 

 

I have on past bikes. My current off road bikes don't. That makes it a real pain to change tires (I go though a lot of tires) so unless I have issues with tires moving on the rims I don't use rim locks.

 

If I was going to ride at under 12psi I would definitely use rim locks.

 

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doc47

Here's an interesting string:

 

http://www.thumpertalk.com/topic/464...e-nuts-or-not/

 

The tube came with a domed metal shield under the two nuts. I assume that goes inside the rim, next to the tube, to protect the rubber and keep crap out. Correct?

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dirtrider

Evening Doc

 

---The tube came with a domed metal shield under the two nuts. I assume that goes inside the rim, next to the tube, to protect the rubber and keep crap out. Correct?

 

I have no idea where that dished metal washer goes. I have about a dozen in my shop junk drawer. I never use that thing as it doesn't seem to add anything to my tube installations or inner tube's life cycle.

 

Remember that tube is sold to be used in a variety of wheels & bike models so it could be for rims with large valve stem holes or cast wheels with sharp edged valve stem holes, or ???. Might even go on the outside to hold down a rubber sealing ring (some older Honda's used a rubber stem bushing).

 

 

My best suggestion when in doubt is to install your new tube JUST as it was installed by your bike's manufacturer when it was built.

 

For me, I don't even use the nuts (just a piece of soft rubber hose) as I hate to walk out of the woods due to a valve stem pulled off the tube. (Actually that is a bit of a lie as I use the nut to hold the stem while mounting the tire then remove it).

 

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jjg3

Just for grins, I sent an email to BikeMaster (maker of BikeMaster tubes) asking what were installation instructions and the purpose each nut serves:

 

John,

 

Thank You for contacting BikeMaster Products.

 

We have been known to install one nut on the inside of the rim and one on the outside of the rim. 2 valve stem nuts, one inner and one outer. The outer nut should not be tighten down to the rim but finger tight against the bottom of the valve stem cap. With this done, it will allow the tube some movement which does happen.

 

Thank You,

 

Daniel Ward

BikeMaster Products

877-848-1320

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doc47

That's interesting. I wonder what is the purpose of the nut inside the rim?

 

Still time to edit this....I found this on a website:

 

"The first nut must be securely fastened to the rubber stem base with a wrench before inserting the tube into the rim and casing.... The second nut must be securely tightened to the rim with a wrench."

Edited by doc47

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