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Fitting inner tubes
Another dumb question that everyone else knows the answer to:
I've just fitted a new inner tube on my '82 alloy-wheeled airhead and I just can't remember where the two nuts go on the valve stem. I've changed 20-30 tyres & tubes by now but find myself completely flummoxed, dammit-I don't remember wondering about it before, even. So I've asked at one garage, two tyre depots and two bikers that change their own tyres, and only one tyre depot fitter agreed with me that both should go on the valve stem on the outside (i.e. on the hub side of the rim,) with the dished washer going between the tube and the rim. It seems to me that whatever the function of the nut nearest the tube, it can still perform that job when placed on the hub side of the rim, and also be locked by the other nut tightened down next to it. On the other hand, if I left one of the nuts on the tube side of the rim it would prevent the tube from seating into the well of the rim. So, you see, I'm confused. Hope I haven't got you folks confused too. Cheers, John. ------------------ Johnefyn |
Hi John,
i can remember disded washers ,double nuts but only just, i'd fit the tude without the dished washer and with only one nut on the outside off the rim as you said,...leave the nut slack bryan |
Hi Bryan, Thanks again, I've just realised it was you who replied to my query regarding g'box end plates just now, as well. Thanks, twice! John ------------------ Johnefyn |
imho...
ABSOLUTELY use the dished washer, very important to protect the base of the valve stem - which is rubber - from getting cut. One nut on the outside would be my preference, locking the valve to the rim snugly, and you could use the second nut against the valve cap, but I don't think it's important. Although according to Continental: "Valve nut (tube type) Only a fitting aid. Should be twisted against the valve cap after fitting the tyre." REF: http://www.conti-tyres.co.uk/contibike/tsafety.htm ------------------ Grant Johnson Seek, and ye shall find. ------------------------ One world, Two wheels. www.HorizonsUnlimited.com |
Hi, Grant,
Well, bugger me! It never ever ocurred to me to tighten one of the nuts against the valve cap! Still, can't argue with Mr.Continental, can we? Er, one small thing before I go-what's ...imho? Thanks, Grant John ------------------ Johnefyn |
imho = "in my humble opinion"
fwiw = "for what it's worth" ymmv = "your mileage may vary" All just added to the "Smilies legend" for future reference when posting. I'll add more as they come to mind. ------------------ Grant Johnson Seek, and ye shall find. ------------------------ One world, Two wheels. www.HorizonsUnlimited.com |
IMHO it’s not smart to twist the nut to the valve cap on a rim designed for tubeless tires. The hole in the rim for the valve is much bigger then the valve so you need some cover to keep the sand out.
Tighten it loosely with your fingers and remember to readjust it when you increase/decrease air-pressure. |
The '82's aren't tubeless despite being alloy rims (iirc).
Note that there are THREE types of holes used for valve stems. LARGE one on tubeless rims for an all-rubber stem. SMALL on tubeless rims for valve stems with threads, ala many BMW's. SMALL hole for tubetype. The two small holes seem to be the same size more or less, but the tubeless one has a flattened surface inside and out so the valve stem can seal properly. I would only twist the nut to the valve cap if there was also a nut to twist to the rim. (Back to the original question - what to do with two nuts) Except - On a pure dirt bike running very low pressures it's normal to leave the nut off so the stem can move - indicating that the tire is turning on the rim. BUT - DO NOT ride with no nut holding the valve stem to the rim on a street bike using TUBES. I have seen valve stems almost cut through by vibrating back and forth in the hole in the rim when not using a nut. Of course on a threaded tubeless stem you MUST use a nut. The nut (on tubetype) should be tightened lightly as Alibaba says. I give just a slight tweak with a wrench. On tubeless threaded stems I tighten it a little more, a good quarter turn. hth... ------------------ Grant Johnson Seek, and ye shall find. ------------------------ One world, Two wheels. www.HorizonsUnlimited.com |
Hi,AliBaba
I think you may have a point with what you said about keeping sand and stuff out of the valve hole. Have you had a look at the Continental website mentioned in Grant's reply, there's a lot in it but precious little regarding changing tyres. I don't know if what I've copied from their site is subject to copyright- it is in the interest of safety, after all (what do you think, Grant?) but here it is............ Fitting tyres Only specially trained persons should fit tyres. Fitting tyres requires that you lubricate both sides of the tyre bead and rim, all the way around. Use a commercial tyre-bead lubricant or soapy water. Do not use a petroleum-based or silicone-based lubricant. Observe the directional arrow on the sidewall. Do not use sealing liquids. Valve nut (tube type) Only a fitting aid. Should be twisted against the valve cap after fitting the tyre. With thanks to Continental tyres for the above excerpt. The impression I get is that they don't really want us to change our own tyres anyway. And, no, I must admit never having seen a valve cap lock-nutted, has anyone else? Many thanks, John ------------------ Johnefyn |
Hmm Conti’s page is creepy:
"Check inflation pressure, and adjust if necessary, on every refuelling stop" Well.... "Avoid impact strain (E.g. curbstones)" Sure I try to, but you know... "Continental does not recommend repairing a damaged tyre by simply fitting a new inner-tube. Due to safety reasons CONTINENTAL recommends to always fit a new tyre instead of repairing it. " Well they don't mention patching so I guess that's okay :-) When it comes to twisting the nut against the valve cap I always did it on my trial-bike to see if the tire moved but I will not do it on the BMW, maybe I had did it if I had rims designed for tubed tires. First of all there is no need, the tire never moves (even with extreme low air-pressure and hard driving) and I don’t want the sand to get into the hole. |
Hi, Ali
I can't qute see what you mean when you say that you screw the nut up to the cap to see if the tyre has moved, there's something I don't understand here, I think. (Though I do realise that that was only on your trials bike) As to Conti's suggestion regarding checking the pressures at every fuel stop, well, of course we all do that, I also try to change the oil and fiter too. As one does, naturally. Just you try and check the pressure on the '82 alloy rims- you lose half the air that's in them, and as for getting the inflator into position, that's a nightmare. I'm about to get some of the 90-degree alloy adaptors and have the wheels rebalanced- does anyone have any thoughts/experience on those? Cheers, John ------------------ Johnefyn |
If the wheel moves the tube will also move.
If the nut is not screwed towards the rim (screwed towards the cap, or in your pocket or somewhere else) the valve will not point directly to the center of the hub anymore if the wheel starts to move on the rim. This is a warningsignal and you can relocate the tube before the valve get ripped out of the tube, which is very hard to repair. If you screw the nut towards the rim it will not be that easy to see if the wheel starts to move and it will be less flexible and rip out the valve earlier then if you had mounted it without a nut. On my bike the wheel has never moved so I always screw the nut fingertight to the rim. I have some adapters made of rubber, they work great, alloy should be more robust. Another option is to bend the inflator so it fits…. |
Ali... Ah-I see what you mean, of course. Mind, as to what you say about bending inflators, the nice people at the filling stations won't like it... Digressing a bit, I see you're in Norway, I'm very fond of your country, and visited it five times in the seventies in my Bedford CA van with student friends, tell me- do they still have oiled gravel (honestly) roads with the lethal corrugations there? They were positively murderous on the hairpin bends in the fjords. You must have one of the most spectacular scenery in the world. Mind, it was horrendously expensive there then. Perhaps all this belongs elsewhwere- the Regional forums in the HUBB; I don't remember much mention made of Scandinavia at all there. Thanks again, J ------------------ Johnefyn |
Hi again,
the advice i posted is correct imho, uk mot road safety testers check the nut isn't tight,...as the valve stems shows if the tube has moved "in service",haynes manuals echo this advice(is that a good thing http://www.horizonsunlimited.com/ubb/wink.gif). i have metzeler,michelin tubes, dating back to early 1980's ,and a new conti tube(d21) 6weeks old,all are single nut/no dished washer. advice as always was posted in good faith |
Hi, everybody,
This is getting serious. All of the responses from you make sense, but they're all slightly different, surely we can't all be right. So what I'm going to do is ask some of the tyre manufacturers. I'll e-mail a few and see what they say about it. Let's see if even they can agree about the right way to do it! Thanks everyone, I'll be in touch. J ------------------ Johnefyn |
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