WM3 Rim Lock on WM2 Rear Wheel.

Edfury828

Edfury828

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In mounting my new Avon Road Riders on my rear wheel, I noticed that my rim lock said "For WM3 Wheel". Not knowing what that meant, I carried on and completed the mounting job.

Having never mounted a tire with a rim lock, I was as careful as I could be to pay attention to what was happening as I went along. With the tire on, the tube in with no air, I poked the threaded shaft of the rim lock with my finger and it freely moved all of the way in and back with no interference... I was expecting it to grab onto the bead or something...

After inflating the tube, it was pressed firmly into the rim. I know now that I should've measured the inside width of the rim in order to identify which WM that it is, but at the time, I did not.

I have measured the outside of the front and rear which are both 2-11/16". I'm sure the wheels are original, and they appear to be WM2. This makes me wonder why I have an old and original looking WM3 rim lock in my (I Think) WM2 wheel?

Is this something people did on purpose back in the day, or is it just a mystery?

Is it actually doing anything other than going for a ride in my Wheel?

What was the purpose of rim locks anyway? Some say safety, to hold your bead together, and some say to keep your Wheel from spinning. I can't tell that mine will be doing either!

I may put a WM2 rim lock in next time my wheel is off, but for now, my wheel is on and balanced, ready to go on the bike... I think I'll be ok? Should I ask someone to hold my beer before I ride? I really don't want to start over!
 
Edfury828 said:
After inflating the tube, it was pressed firmly into the rim. I know now that I should've measured the inside width of the rim in order to identify which WM that it is, but at the time, I did not.

I have measured the outside of the front and rear which are both 2-11/16". I'm sure the wheels are original, and they appear to be WM2. This makes me wonder why I have an old and original looking WM3 rim lock in my (I Think) WM2 wheel?
Click to expand...

If the rims are original Dunlop then they should be stamped WM2 - 19 with an MB (drum) or MC (disc) number. The nut holds the rimlock in position once the tyre has been inflated. The rimlock (security bolt) therefore is normally a WM2.
andover-norton.co.uk

Andover Norton - SECURITY BOLT (WM2) - 06.8090

SECURITY BOLT (WM2)
andover-norton.co.uk
 
I don't want to offend, but to state I noticed that my rim lock said "For WM3 Wheel". Not knowing what that meant, I carried on and completed the mounting job. Sets the alarm bells ringing. Can i suggest you change your complete mode of operation and attitude as i would be very wary of anything that you have done.
The WM3 rim lock is substantially wider than the WM2 one. I'm surprised that you got it fitted, which begs the question what have you got fitted? possibly someone in the past has shaved down a WM3 lock to fit a WM2 rim. You are going to have to take it out and compare it against a known WM3 rim lock. Width of a WM2 chrome Mk3 rim is a tad over 68mm
 
Edfury828 said:
In mounting my new Avon Road Riders on my rear wheel, I noticed that my rim lock said "For WM3 Wheel". Not knowing what that meant, I carried on and completed the mounting job.

Having never mounted a tire with a rim lock, I was as careful as I could be to pay attention to what was happening as I went along. With the tire on, the tube in with no air, I poked the threaded shaft of the rim lock with my finger and it freely moved all of the way in and back with no interference... I was expecting it to grab onto the bead or something...

After inflating the tube, it was pressed firmly into the rim. I know now that I should've measured the inside width of the rim in order to identify which WM that it is, but at the time, I did not.

I have measured the outside of the front and rear which are both 2-11/16". I'm sure the wheels are original, and they appear to be WM2. This makes me wonder why I have an old and original looking WM3 rim lock in my (I Think) WM2 wheel?

Is this something people did on purpose back in the day, or is it just a mystery?

Is it actually doing anything other than going for a ride in my Wheel?

What was the purpose of rim locks anyway? Some say safety, to hold your bead together, and some say to keep your Wheel from spinning. I can't tell that mine will be doing either!

I may put a WM2 rim lock in next time my wheel is off, but for now, my wheel is on and balanced, ready to go on the bike... I think I'll be ok? Should I ask someone to hold my beer before I ride? I really don't want to start over!
Click to expand...
I can't imagine how you got it in, but I would not ride with it. IMHO, much better to have none than one that is too wide as it deforms the tire and probably the rim.
 
On a road bike the rim locks are superflous . With road-going tire pressure the rim isn't going to slip on the tire. If it was a knobby on a dirt bike then yes, it's needed because you're running sub-20 psi typically. Rim locks just mean you need a bunch of those chrome wheel weights on the spokes opposite it.
 
dobba99 said:
I don't want to offend, but to state I noticed that my rim lock said "For WM3 Wheel". Not knowing what that meant, I carried on and completed the mounting job. Sets the alarm bells ringing. Can i suggest you change your complete mode of operation and attitude as i would be very wary of anything that you have done.
The WM3 rim lock is substantially wider than the WM2 one. I'm surprised that you got it fitted, which begs the question what have you got fitted? possibly someone in the past has shaved down a WM3 lock to fit a WM2 rim. You are going to have to take it out and compare it against a known WM3 rim lock. Width of a WM2 chrome Mk3 rim is a tad over 68mm
Click to expand...
That was basically it. Perhaps I could've worded it better? The rimlock gave every appearance to have been in the wheel from day one. My assumption (which has caused this slight embarrassment) was that the wheel must be a WM3 although, I did not know what that designation meant. If not, maybe a WM3 lock in a WM2 wheel was an upgrade? Someone put it there for some reason. That's where I screwed up. Whatever the situation, it has been existing as such for some time.

In the moment, I just wanted to put it back together and go. I am seeing now that amazon can get me a WM2 type in one day. That would fit my schedule as long as the part fits my wheel. Hopefully, it will actually serve a real purpose. I have read many people leave them out...
 
I could take the one I have out of my extra wheel if you want to change it today and you can give it back to me once you order another one to replace it. I actually don't know if it's a WM2 bead lock, because I never looked at it's markings, but I've had it in a WM2 rim for 40 years so I assume it is.

I'm out rte 90 near exit 22 if you want to pick it up, just shoot me a message back channel that you want it and I'll pull it out of the wheel to check that's it's actually a WM2 bead lock.
 
Thomasa said:
With road-going tire pressure the rim isn't going to slip on the tire.
Click to expand...
Correct as long as your tyre stays inflated but if you lose pressure from a slow leak then the slippy chrome will allow the tyre to creep and potentially pull out the valve from the inner tube causing sudden deflation. Hence why alloy wheels have knurling where the tyre bead sits but these Dunlop rims are smooth chrome. On a front tyre you should see it deflate hence nn rim lock on road bike front wheels but the rear is unseen when riding.
 
o0norton0o said:
I could take the one I have out of my extra wheel if you want to change it today and you can give it back to me once you order another one to replace it. I actually don't know if it's a WM2 bead lock, because I never looked at it's markings, but I've had it in a WM2 rim for 40 years so I assume it is.

I'm out rte 90 near exit 22 if you want to pick it up, just shoot me a message back channel that you want it and I'll pull it out of the wheel to check that's it's actually a WM2 bead lock.
Click to expand...
Thanks o0norton0o, that's a very generous offer, which I do appreciate, but I can have a new one on my porch by tomorrow. I have appointments after work today, so no time as usual!
 
Thomasa said:
On a road bike the rim locks are superflous . With road-going tire pressure the rim isn't going to slip on the tire. If it was a knobby on a dirt bike then yes, it's needed because you're running sub-20 psi typically. Rim locks just mean you need a bunch of those chrome wheel weights on the spokes opposite it.
Click to expand...
I have no experience with these older rims and rim links, but it seems to me too that the tire is not going to spin or slip. I'm more concerned about the rim lock holding the tire on the rim in case of a flat at speed. Does it do that (assuming you have the right one)?
 
Off road motorcycle tires benefit from rim locks because of the low pressures used.

BUT.......comparing vintage WM rims with modern rims. With our older type rims (on the highway) there's no "safety lip" (look it up) In short, there's nothing (except the rim lock) keeping the bead from falling into the rim's well if pressure is lost. IF it does.....the tire can actually come off the rim. Some of you have already heard my "story"........so I'll not bore the rest of you with it. Do a little research on rim profiles.......you'll see it.
 
The Vintage rims are tube-type. Modern rims are usually tubeless-type. Comparing apples and oranges is just talking about fruit! Many today use tubeless tires (Avon RoadRider) on "WM" rims - hard to install - I've heard no horror stories about flats.

I've had tires quickly go flat with no rim locks and with two rim locks using Dunlop K70 tires. Squirrely yes, crash, no. I've never had a bike with one rim lock go flat, but I would be more worried about that than with none or one. The tire dropping into well just means stopping with a flat tire. Not sure it would be as "nice" with one rim lock!

Knobby tires at low pressure need the rim lock or locks to keep the tire and therefore tube from creeping and tearing off the fill valve.
 
Gordoninnc said:
Off road motorcycle tires benefit from rim locks because of the low pressures used.

BUT.......comparing vintage WM rims with modern rims. With our older type rims (on the highway) there's no "safety lip" (look it up) In short, there's nothing (except the rim lock) keeping the bead from falling into the rim's well if pressure is lost. IF it does.....the tire can actually come off the rim. Some of you have already heard my "story"........so I'll not bore the rest of you with it. Do a little research on rim profiles.......you'll see it.
Click to expand...
I was thinking of a way to tell the OSMR story.
Very glad you had the skills & fortitude to ride it out. 🏁💪🏻
 
Only bikes I have with rim locks and need it is the BSA Victor Specials with recommended 16 psi. As I have the valve stem nut slightly loose, I'll see if the tyre has slipped by angle of valve stem.
 
concours said:
I was thinking of a way to tell the OSMR story.
Very glad you had the skills & fortitude to ride it out. 🏁💪🏻
Click to expand...
I'm glad you hung on too Greg! I've just had two flats so far. One on my 2015 T-100 and one on my 2915 Enfield. Both on the rear, spoke wheels with tubes and modern safety beads and modern tires. They got "loosey-goosey" and it was scary enough, but the beads held on! I did roadside tube patches and went on my way.

Is there a link to the infamous OSMR story? I am curious but can't find it!

On the subject of stem installation I do as pictured. That drawing was on a major tire manufacturer's site, I think it was Michelin. They reccomend it.
 

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  • WM3 Rim Lock on WM2 Rear Wheel.
    motorcycle valve fitting.gif
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Re: the illustration of the valve stem lock nuts. What is the point of leaving a gap between the rim and the locknuts?
I have encountered other designs which call for a locknut BETWEEN the tube and the rim, which always struck me as weird.
 
Stephen Hill said:
Re: the illustration of the valve stem lock nuts. What is the point of leaving a gap between the rim and the locknuts?
I have encountered other designs which call for a locknut BETWEEN the tube and the rim, which always struck me as weird.
Click to expand...
When the tyre starts to slip, instead of ripping off the valve, the valve stem gets angled. Easy to see and with some effort possible to correct.
If you have a routine of checking that the valve stem points toward the wheel centre.
The purpose of the nut(s) is to make it easier to fill an empty inner tube.
 
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