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Thread Like Summary
Allan G, Gordon Gray, Lorenzo, NickL
Total Likes: 12
Original Post (Thread Starter)
#851505 06/13/2021 3:41 PM
by Lorenzo
I may be having a spot of bother balancing my rear wheel.
Wheel is totally standard, with original Dunlop chrome rim stamped 37-7030 and galvanised steel spokes, and I originally removed the tyre to replace a single undersized spoke that the p.o. had fitted.
At the same time I replaced the inner tube as the old one had been patched, and fitted a security bolt / rimlock which at the time was missing.
Security bolt is a moulded rubber type (Wassell ?) and weighs 160gm
Re-assembled, the wheel was obviously WAY out of balance, although I confess I had made the absent-minded mistake of fitting the tyre with the balance mark next to the valve, rather than next to the heaviest point i.e. the security bolt/rimlock.

I'd very much like to get the balance right this time.......
Does anyone have an average weight for a WM3 (215) sec. bolt ?

Thanks in advance for any help (but please don't suggest removing sec. bolt).
Liked Replies
#851842 Jun 18th a 05:51 AM
by TR7RVMan
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).
2 members like this
#851571 Jun 14th a 11:57 AM
by kommando
Originally Posted by rory brennan
not claiming any knowledge here, but i assumed that rimlocks were to stop the tyre spinning on the rim at low pressures - like on my dirt bikes -
i can't remember any of my road bikes (with tubed tyres) having rim locks and wonder why the safety issue wouldn't apply to tubeless tyres, that don't have rimlocks
very happy to have my assumptions shown to have made an ass out of you and me
The problem is the chrome rims have no mechanism to stop the tyre creeping with low pressures, so if you get a puncture but do not notice the drop in pressure in time the tyre can creep around and pull the valve stem out of the inner tube, then the bead can drop into the spoke recess. If you look at modern alloy rims on the inside they have serrations where the tyre bead sits to provide resistance to bead creep and on MT profile rims a raised section to stop the bead dropping into the spoke area.
1 member likes this
#851522 Jun 13th a 07:24 PM
by TR7RVMan
Hi Lorenzo, I always balance rear wheel as well as the front. I have truing stand so do off bike. The stand comes have less friction than bearings but on bike will certainly be close enough.

Depending on how much it’s out, rear tire can make bike feel slightly twitchy or light. While good balance both wheels gives bike grounded solid feel. Really start notice oh this 70-75 mph with only a few oz out.

I always keep/use rim lock as it keeps tire on rim in a blow out. Hopefully preventing loss of control. So you are not wasting time.

I’ve been in your position several times. The rim locks are very heavy. Seems on older bikes locks were 180deg. Stem centered. That was easy. My ‘73 Tiger locks & stem is about in 3rds. Always needs weights.

I’ve mounted dozens of tires. I’ve been finding the weight dot is variable to what position takes less weights.

I’ll line it with stem & test. If needs too much weight I’ll spin tire on rim. Retest. As you know spinning tire not so easy. I keep at it until I think is about as good as it’ll be, no weights. Then add weights.

Saying all that, it doesn’t really matter if you use 1 or 4 oz. of weights. It’s the final result of no wheel movement that counts. But stagger spoke weights such they are in line with center of rim average overall so they have minimal effect on the dynamic balance. So stick on would half one side of spoke line, half the other.

Any weights will work. I like the original spoke type. 2 sizes only. I cut bottom off the small size to get more accurate, keeping all the weights on neighboring spokes. Just looks cleaner to me.

Balance is balance. Spinning tire just saves weights. To me 4 or 5 weights in a row looks funny. Sure it adds to overall rotating & unsparing mass, but I’ve ridden bikes with lots of weights & I can’t feel it.
1 member likes this
#851758 Jun 16th a 06:20 PM
by Gordon Gray
Gordon Gray
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.

1 member likes this
#851810 Jun 17th a 03:44 PM
by John Healy
John Healy
Ok gentlemen Time!
1 member likes this
#851811 Jun 17th a 03:47 PM
by Lorenzo
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.


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........
1 member likes this
#851803 Jun 17th a 12:55 PM
by Hillbilly bike
Hillbilly bike
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.

Disrespectful? You gotta be kidding...
1 member likes this
#851832 Jun 18th a 12:04 AM
by koan58
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.
1 member likes this
#851854 Jun 18th a 03:21 PM
by Chris Brasier
Chris Brasier
Have you considered fitting these Lorenzo?

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).

1 member likes this
#851801 Jun 17th a 11:53 AM
by Hillbilly bike
Hillbilly bike
I throw locks in the trash...
1 member likes this
#851840 Jun 18th a 05:17 AM
by BigBars
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 😜.
1 member likes this
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