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Wow…..I probably have a few more locks for WM3 rims ( none as pretty as that one) I’ll weigh them tonight to see if there’s any differences. My earliest ones could be early 60s.

I use modern lite weight locks now…(Motion Pro) ….probably an ounce lighter than the Dunlop shown.

Gordon.

Last edited by Gordon Gray; 06/16/21 6:15 pm.

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Hi, It doesn’t matter where the heavy is. Balanced is balanced.
Rim lock if one only or in 1/3rds compared to 180 apart just means you’ll likely need more weight. Trial fitting tire in different position often allows less weights needed. No matter balanced is balanced.
Out of round tire, or tire with hard spot will static balance perfectly, but not roll smoothly. That’s another issue & subject, as is runout of tire.

Playing around with wheel, tire removed on truing stand it’s often out an oz. or more.

When you get wider modern tires dynamic balancing is a must.
I’ve not done it, but would be fun to static balance our skinny tires carefully, then put it on the spin balancer.
Don

Last edited by TR7RVMan; 06/16/21 5:50 pm. Reason: Changed sentence

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Okay……no photos because I was in a hurry. I’m working across the street from my house so I ran over to check some more locks.

I have a dozen or so locks but only 3 more that are definitely Dunlop and for WM-3 rims.

After weighing four total…..the weight went from as low as 3.42 oz to as high as 3.70 oz.

Hope that answers the OP’s question.

Gordon

Last edited by Gordon Gray; 06/16/21 7:21 pm.

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Gordon- My last post was a bit silly so was hoping I had deleted it before anyone saw it! smile

Dave

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Originally Posted by dave jones
Gordon- My last post was a bit silly so was hoping I had deleted it before anyone saw it! smile

Dave

I saw it and had no problem with it at all. 😊 I have to agree with you and know I’m guilty of it at times.

Thank goodness for that “delete” button…….I use that too. 😇

Gordon

Last edited by Gordon Gray; 06/17/21 10:55 am.

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I throw locks in the trash...


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
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But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
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Originally Posted by Hillbilly bike
I throw locks in the trash...

That’s kinda disrespectful to the OP. My guess is he doesn’t give a damn what you do with them. He said he wants to use them.

Perfect example of what Dave was taking about.

Gordon


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Originally Posted by Gordon Gray
Originally Posted by Hillbilly bike
I throw locks in the trash...

That’s kinda disrespectful to the OP. My guess is he doesn’t give a damn what you do with them. He said he wants to use them.

Perfect example of what Dave was taking about.

Gordon
Disrespectful? You gotta be kidding...


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
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But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
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Ok gentlemen Time!

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Originally Posted by Gordon Gray
After weighing four total…..the weight went from as low as 3.42 oz to as high as 3.70 oz.

Hope that answers the OP’s question.

Gordon

Indeed it does - thanks very much Gordon for a straight answer to my question, and thanks again for taking the trouble to measure the others you have for a meaningful comparison.

Any problems with the Motion Pro lightweight locks ? I've read reports that they are not suited to use in a road bike (i.e. one using higher pressures than dirt or MX bikes). It's there on the internet, so it must be true.....(!)

I don't feel dissed by what Hillbilly does with his bike(s) or parts of it - it's his bike, and he does what he likes with it.

Many of the problems with my own machine arise from trying to get it back to some sort of standard order, the p.o having done what he liked to it when it was his........


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Lorenzo, I haven’t had any problems with the lite weight security bolts. From what I can tell they are pretty much the same as the Dunlop’s as far as construction goes…..just different material.

That said, I don’t use my bikes in anger, just bimble around so I’m not pushing things.

Take care, stay healthy


Gordon


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My apologizes Mr Healy.......I forgot whose house I was in. blush

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Hi All, How do you size the rim lock? Sure if you take an old genuine to Cycle Gear you might be able to match it up. They have some in stock at my local store.

But what if yours are missing & you don't have sample. What about the drop center in rim. how does that effect rim lock?

Here's one on eBay. Replica Dunlop per seller. What would it weigh?

Still no matter so long as you balance wheel. The extra weight is just adding to the mass of assembly, near the outside so it might slow you a bit & effects unsprung weight.
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I haven’t had a security clamp fitted since replacing with alloy rims in 1981.

In 45 years of motorcycling I’ve not experienced the dramatic blowout that some others appear to have, with the luxury of having experienced it both with and without rimlocks to compare, as some say they have.

Punctures on tubed tyres tend to be due to a nail (or similar long pointy thing) penetrating the thickness of the tyre and ultimately (and sometimes after quite a further period of tyre wear) piercing the tube.

In all this time, I’ve not known that to release all pressure instantly (as in a blow out).
Perhaps I’ve been lucky, but I’ve had dozens of punctures, all of which have given warning, and have been repairable with patches.

Now if you went over a police stinger, a different matter.

A security bolt is essentially a metal shoe that clamps that part of the tyre bead into the angle of the rim. The rubber is just to protect the tube from the edges of the metal.

I don’t know why Gordon’s says “without well filler”, anybody?
I’m sure such a WM3 clamp would be fine in any WM3 rim.

I think the biggest likelihood of a blow out is if a puncture results in a gradual loss of air pressure un-noticed. Then when the tyre is quite soft, it can slip on the rim and take the valve out – that will be a blow-out.

As has been said, it is hard to imagine folk not being aware of that developing situation, but a security bolt just might save a life in that event.
Except that combinations were common up to the 70's, and a puncture wouldn't be quite so obvious then.

One last thought, Triumph were still putting these locks into rear wheels late into the 70’s, were they being put into the front wheels as well?
It seems to me that a blowout on the front would be many times the horror of one on the rear.

Merely thoughts.

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Seems to me I've read here that modern tires don't really need rim locks particularly when coupled with modern rims. I myself have never experienced the much dreaded and feared but seldom seen catastrophic tire failure in almost 60 years of Triumph M/C riding. I also have never had a flat and I've been in some remote places where a flat might have been deadly. Maybe I've been lucky.


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I have only seen it on the rear in part books. I wonder if it was primarily to tame tire slip on the rim considering the massive raw power available from these bikes, coupled with the lower pressure that folks used long ago 😜.


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Hi, Some motorcycle rims, are "safety rims" there is a small raised area, that keeps bead in place. This has been common practice in automotive & Harley 16" & later Sportster rims for years. In case of flat it keeps bead on rim. Until carcass disintegrats. Safety rims need "bead breaker" tool or the like. Possible to use tire irons, but not easy.

Older Sportsters used sheet metal screw through rim bead wall into tire bead. Pay attention to length! Actually works quite well & easier than rim locks. They will tear valve stem if not secured.

A flat on front more or less allows steering to a degree. Flat on rear if like a blowout allows rear to move sideways in more unpredictable manner than flat in front.

Rim locks are certainly a personal choice. Once you get hang of them, no big deal when changing tires. Anytime we get a flat & it's slow enough to ride out & not cause a fall, pull over & thank God for his mercy. Flats can through you & fast. Mom's right motorcycles are really dangerous.

Many dirt bikes use rim locks. They'll slip tire on rim no problem.

I had photos & weights of my rim locks, but for the life of me, can't find them.

Who knows the real reason Triumph fitted them. I don't recall my Hondas having them. 90, 305, 350cc. My '64 Mountain Cub has 2 (in 3rds).
Don


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Originally Posted by koan58
I snip…

I don’t know why Gordon’s says “without well filler”, anybody?
I’m sure such a WM3 clamp would be fine in any WM3 rim.

Snip….

One last thought, Triumph were still putting these locks into rear wheels late into the 70’s, were they being put into the front wheels as well?
It seems to me that a blowout on the front would be many times the horror of one on the rear.

Merely thoughts.

That rim lock pictured came out of a wheel off a BSA unit single. Looked typical with rusty spokes and pitted chrome. But the lock and tube looked almost new except for the rusty bolt. All four of the locks I have I can identify as Dunlop have the same verbiage stamped on them. I’ve posted a photo of it before asking about the “well filler” but never got an answer ( sound familiar Dave? 😂) Maybe this time around someone will enlighten us?

I have experienced ( with a real life witness off this board following behind me) a front tire go flat where the tire came off the rim. I’ve told the story several times on here and won’t bore you again with it. But……you watch that front tire wad up around the forks every revolution ( try as you may you can’t take your eyes off of it) it’s an eye opener.

Ever try to roll your bike across the shop floor with a flat front tire……yea a pain….now pull the tire off the rim and see how much fun that is. At speed, visions of flying over the handle bars is what I experienced.

Kinda like any insurance……..it’s only useful when you need it.

Gordon


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"Security bolts are fitted to the rear wheel to prevent tyre 'creeping' on the rim when it is subjected to excessive acceleration or braking. Such movement would ultimately result in the valve being torn from the inner tube." WSM section F13
As I remember, even my lowly Yamaha 60 had them.

As for the original question, The last tire change on my T150 I bought new rim locks made by Tusk. I didn't think to compare the weight with the worn out Dunlop locks. But, they did require significant adding of weights opposite to balance the wheel.


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Have you considered fitting these Lorenzo?

https://www.dynabeads.co.uk/dynabeads_bike.php

I have an ounce in each of my tubes with no other balancing weights attached to spokes, I don’t experience any wheel wobble up to speeds that I’m comfortable with. On the front wheel the beads replaced a ‘traditional’ weight and kept things balanced so I’m confident they work (though the internet does have divided opinions).

Chris


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Hi,
Originally Posted by DavidP
"Security bolts are fitted to the rear wheel to prevent tyre 'creeping' on the rim when it is subjected to excessive acceleration or braking. Such movement would ultimately result in the valve being torn from the inner tube." WSM section F13
As I remember, even my lowly Yamaha 60 had them.
Otoh, bikes like Kawasaki H2's and Z1's didn't?

Originally Posted by koan58
seems to me that a blowout on the front would be many times the horror of one on the rear.
Don't know about "horror" but, like Gordon, ime a front wheel puncture on a single-track vehicle is one of the best natural laxatives known; anyone who can bottle it will be rich.

Originally Posted by koan58
Triumph were still putting these locks into rear wheels late into the 70’s, were they being put into the front wheels as well?
The question's been asked before. The answer's no. Why not? Triumph and BSA fitted them when other motorcycle makers didn't and before the time when vehicle makers discovered buyers would pay more for things that were perceived as additional 'safety'. Another possible reason is rear wheel punctures were perceived as 'more likely' - the "nail (or similar long pointy thing)" lies flat on the road 'til the front tyre rolls over it and flips it up, then it penetrates the rear tyre. frown

Hth.

Regards,

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Stuart wrote " Don't know about "horror" but, like Gordon, ime a front wheel puncture on a single-track vehicle is one of the best natural laxatives known; anyone who can bottle it will be rich.


Thank you sir.... clap....I needed a good laugh. laughing ohno laughing thumbsup

The fellow following behind me ( Bill....aka No Name Man) thought I was having a heart attach. I carry spare tubes ( yes plural) and tools to change them out. I was a bit of a wreck ( pun intended) and Bill finally took the tools out of my hands and finished the job......bless him, I'll never forget that act of kindness. The rest of the group was ahead of us and by the time they got back to us the repair was well on the way. BSA didn't put rim locks on that bike's front end....but Gordon did when he got home with it.

I agree 100% with Lorenzo ..........it's your bike, you can do anything you want with it.

Gordon

And it was caused by on of these little tacks.......in black that was stuck between the treads and out of sight.....no telling how long it had been in there.

IMG_8044.jpg
Last edited by Gordon Gray; 06/19/21 11:54 am.

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