tire tube nut(s)

gripper said:

I saw a novel way to stop tyre creep on a motocrosser many years ago. 8 or 10 self tapping screws through the edge of the rim into the tyre bead. Probably standard practice in the scrambler world in those days.

Click to expand...

I'm afraid my shouldered Excels just wouldn't look the same anymore............as this thread free falls of the cliff.

Triton Thrasher said:

This is attributed to an email from Michelin, on an Ariel forum:

The conical washer sits over the inner tube valve stem and should follow the contour of the valve so that the convex side sits against the wheel rim when fitting.

Once fitted to the wheel the two lock nuts sit on the valve cap side of the wheel rim. After fitment and inflation to the correct pressure, the two nuts should be backed up towards the valve cap, and locked against each other.

This is not usually an issue on correctly inflated road going tyres, but should there be any slippage of tyre on the rim, during heavy braking or acceleration for example, the inner tube could be pulled around slightly with the tyre and if the inner tube is bolted to the rim the valve can be ripped out. If the lock nuts are raised towards the valve cap then inner tube has some leeway to move before this happens. Any movement is thus obvious as the valve stem will no longer be straight and pointing at the centre of the hub, but will be pulled round at an angle.

Click to expand...

http://forum.arielownersmcc.co.uk/viewtopic.php?t=3880&start=10#p25405

Click to expand...

I only use one of the nuts supplied lightly snugged on the stem to the out side of the rim. It always seemed to me a nut on the inside, securing the conical washer to the tube would put unnatural localized stress on the tube at the stem.

gripper said:

I saw a novel way to stop tyre creep on a motocrosser many years ago. 8 or 10 self tapping screws through the edge of the rim into the tyre bead. Probably standard practice in the scrambler world in those days.

Click to expand...

and in the 1/4 mile sprint world :!:

I have seen self-tappers used on road racers. However I think that is butcherous. A rim lock has to be balanced, so in that way self-tappers are probably better.

It just seems counterintuitive to not use the nut(s) to secure the stem to the rim. Other than dirtbikes, most tube-type wheels (other than for ditbikes) don't come with rim locks these days, and if the tire and tube are shifting back and forth, a loose stem would appear to take more stress than if it was nutted up snugly. I think I'll keep on doing them the way I always have because it seems to work.

Danno said:

It just seems counterintuitive to not use the nut(s) to secure the stem to the rim. Other than dirtbikes, most tube-type wheels (other than for ditbikes) don't come with rim locks these days, and if the tire and tube are shifting back and forth, a loose stem would appear to take more stress than if it was nutted up snugly. I think I'll keep on doing them the way I always have because it seems to work.

Click to expand...

If the tyre moves, the valve will be torn out of the tube.

But you're right: you can get off with bad practice for years.

On mountain bikes, before running tubless, the front tires would often "walk" around the rim enough to tear out the valve stem, if it was nutted up, when braking hard on a serious downhill. This seemed to be worse if talcum powder was used liberally on the tubes when mounting the tire (slippery you know). Older steel rims sometimes would have knurling on the bead in attempt to prevent this. Larger tires, having more traction, were worse. I have seen speedway rear tires with the valve stem routed out through the sidewall of the tire rather than through the rim to let it slip and not flat. On the mountain bikes when you would see the stem getting twisted it was time to stop, let the air out, slide the tire and air up again. Easy on a bicycle even at trail side by hand. I use the nut to keep the tube in place while mounting the tires if they're not tubeless. On my MGB, wire wheels with tubes, there are no nuts just a rubber covered stem. I have to grab the stem with a hemostat, or similar, to keep the stem in place while struggling with mounting the tire. This was mentioned earlier in the thread also.
However on morotbikes that don't spin the tires much it's probably moot. I usually have a bit of a hard time just popping the bead from the rim, any tips here?
Lance

Triton Thrasher said:

Danno said:

It just seems counterintuitive to not use the nut(s) to secure the stem to the rim. Other than dirtbikes, most tube-type wheels (other than for ditbikes) don't come with rim locks these days, and if the tire and tube are shifting back and forth, a loose stem would appear to take more stress than if it was nutted up snugly. I think I'll keep on doing them the way I always have because it seems to work.

Click to expand...

If the tyre moves, the valve will be torn out of the tube.

But you're right: you can get off with bad practice for years.

Click to expand...

Works for me. The only one I've ever seen torn was with a loose nut. Have you seen one torn with a tight one?

L.E.N. said:

I have to grab the stem with a hemostat, or similar, to keep the stem in place while struggling with mounting the tire. This was mentioned earlier in the thread also.
However on morotbikes that don't spin the tires much it's probably moot. I usually have a bit of a hard time just popping the bead from the rim, any tips here?
Lance

Click to expand...

Thee's a tool for both those jobs.

For pulling a valve stem through the hole when changing a tube:



For breaking beads, if you don't have a tire changer with a vead breaker

Sorry, double post. The "DELETE" option seems to go away after a time.

My original wheel for my '70 commando lacked the cush drive feature of later models, but it did have a bead lock fixture on the rear tire which bolts onto the rim through a hole opposite the hole used for tube's stem. When I first saw the bead lock mechanism, I actually asked my friend, "WTF is this thing for?" and he explained that if the tire slips on the rim during a fast take off, the slippage can shear the valve on the inner tube right off, giving you a flat, and the bead lock prevents slippage.

In all the years I ran tubes on my commando, I never had a flat or had any cocking of the tire stem, so obviously I never had any issues with tire slippage. Were bead locks not used on later model commandos?? or do some people just not bother installing the bead lock because tire slippage isn't all that common?

Danno said:

Triton Thrasher said:

Danno said:

It just seems counterintuitive to not use the nut(s) to secure the stem to the rim. Other than dirtbikes, most tube-type wheels (other than for ditbikes) don't come with rim locks these days, and if the tire and tube are shifting back and forth, a loose stem would appear to take more stress than if it was nutted up snugly. I think I'll keep on doing them the way I always have because it seems to work.

Click to expand...

If the tyre moves, the valve will be torn out of the tube.

But you're right: you can get off with bad practice for years.

Click to expand...

Works for me. The only one I've ever seen torn was with a loose nut. Have you seen one torn with a tight one?

Click to expand...

Nut loose or tight, the valve will tear out if the tyre slips far enough. With it loose, you might get a warning, by way of the valve pointing a funny way.

I've never had a tyre creep, that I remember, nut tight or nut loose.

do some people just not bother installing the bead lock because tire slippage isn't all that common?

I don't know about others, but I gave up fiddling with that bead lock long ago. For me, it was just something that made the wheel heavier, and complicated the balancing process.
Into the bin, no regrets and no problems.

o0norton0o said:

Were bead locks not used on later model commandos?? or do some people just not bother installing the bead lock because tire slippage isn't all that common?

Click to expand...

My 75 MkIII has a bead lock on the rear, which I still use, but only 'because it's there'.

To add to the debate I'm a nuts loose guy, I was taught as others here were that it allows one to see if a problem is emerging, rather than turning a problem into a disaster.

Take a look at the recommended pressures for tyres when these bikes were new. This is why rim locks were fitted & especially to rear wheels. With modern tyres pressures are higher & there is less chance of slip.

I sometimes wonder about the lubricant used when fitting tyres. Sometimes the tyre is stuck very strongly to the rim - not something I ever rely on with a race bike. If you pull the valve out of the tube at a race meeting, it can be very inconvenient. If you use a rim lock, you know where you are.

Soapy water for removal, NoMar tire paste for mounting. I used to mou7nt them dry to avoid leaving any slippery residue, but this stuff dries and does not stick or slip.

There is no need for a nut on the inside. See the illustration previously posted by Triton Thrasher on page 1.

For me, there are two uses for outside nuts:
(1) to hold the stem when I put the air chuck to it, and
(2) to keep the stem from dropping back inside the rim while I'm fitting the tire and using the tire irons.

The first also serves on a later day when you try to add air to a low tire and your air chuck chases the stem down as it retreats to the inside of the rim. That's where prior poster's picture of the two nuts jammed against each other makes sense - keeping a nut handy for that task - while also keeping the nut up and off the rim so that the tube is still free to "walk" a bit, angling the stem, and thereby visually warning the operator of an imminent flat by stem tear because of tire/rim slippage.

As for low pressures, with dirt bikes I run as low as 5 PSI to enhance traction. Rim locks are essential for that and in case the rim lock slips, I don't run a nut on the valve stem. On sport bikes, with modern 17" (tubeless) meatballs, I have run as low as 25 PSI, depending on the tire and expected ride.

Generally, whether tube or tubeless, I run as low a pressure as conditions allow so that the tire warms quickly and presents the largest contact patch to the road while also yielding the most pliable conformity to the road surface, tire mileage/longevity be damned. The primary condition I consider in setting PSI is the average speed expected, higher speeds = higher PSI, lower speeds = lower PSI.

'Generally, whether tube or tubeless, I run as low a pressure as conditions allow so that the tire warms quickly and presents the largest contact patch to the road while also yielding the most pliable conformity to the road surface, tire mileage/longevity be damned. The primary condition I consider in setting PSI is the average speed expected, higher speeds = higher PSI, lower speeds = lower PSI.'

I suspect a lot of guys never think about their tyre pressures, even when it rains. The problem can be that if the pressure is too low, the bike stops being nimble so with the Battlax tyres I run about 32 pounds pressure in the dry and about 5 pounds lower in the wet. I notice that these days, the young guys are not good in the wet. I think it is because they have become reliant on the grippy modern tyres. Also my bike handles a lot differently to a modern bike, it is usually much more upright in corners even when turning under the opposition - probably due to the steering geometry.