Author Topic: Rim lock. Yes or no?  (Read 366 times)

Offline mark

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Rim lock. Yes or no?
« on: 17.09. 2022 05:44 »
The restored rear wheel that came with my Super Flash project has had the hole for the rim lock welded up. I need to decide whether to drill it out and install a rim lock or leave it out. All of my other bikes have one. Anyone running a bike without one?
1955 Road Rocket
1953 Super Flash



71 Norton Commando Roadster 750


Australia

Online Rex

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Re: Rim lock. Yes or no?
« Reply #1 on: 17.09. 2022 10:03 »
Me. I haven't used them since I had a Bonnie many years back. Just keep a watchful eye on the valve angle.

Offline Black Sheep

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Re: Rim lock. Yes or no?
« Reply #2 on: 17.09. 2022 10:57 »
They are there to keep the tyre on the rim in event of a blow out. The choice is yours. My bikes do have security bolts. A tyre coming off the rim at speed isn't nice.
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Online KiwiGF

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Re: Rim lock. Yes or no?
« Reply #3 on: 17.09. 2022 12:30 »
I reckon no, I have always thought they were for trials bikes with lowered tyre pressure, not road bikes.

I could be wrong…..but I dont bother with em…some rims have “serrations” that help increase grip between tyre bead and rim, thus helping prevent tyres rotating relative to the rim, then you definitely dont need one, also the modern tyres need higher pressure which helps prevent rotation…

Bugger i might have started another “tyre thread”  *pull hair out*
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
1968 B44 Victor Special (3rd finished project)
2001 GL1800 Goldwing, well, the wife likes it
2007 KTM 950 Adventure, cos it’s 100% nuts

Online RDfella

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Re: Rim lock. Yes or no?
« Reply #4 on: 17.09. 2022 13:09 »
Never known them as rim locks - first thing I thought of was the one on my bathroom door ....
Security bolts is what I've always known them as and, as KiwiGF says, used on trial bikes when running at ultra-low pressures to prevent tyre slippage on the rim. Another device we used in sand racing was a special tyre where the valve came out the side of the tyre instead of the rim so, if the tyre slipped, the valve wouldn't be pulled out.  Serves no purpose on a road bike except to unbalance the wheel.
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Online Rex

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Re: Rim lock. Yes or no?
« Reply #5 on: 17.09. 2022 17:28 »
Don't know about "serves no purpose" though. Triumph and BSA fitted them to the higher powered bikes (they weren't trials bikes either!) to limit tyre creep on fast take-offs, and given the tyres of the time they must have thought them necessary or they wouldn't have wasted the money.
Given that the two security bolts/rim locks and the valve were all 120' apart the balance wasn't that far out.

Online RDfella

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Re: Rim lock. Yes or no?
« Reply #6 on: 17.09. 2022 18:59 »
Quote
to limit tyre creep on fast take-offs,

On a BSA??? C'mon. A sales gimick. Nowt's a faster take-off than a sprint or hill-climb start and I've never seen a security bolt used for that. My Firestorm does 0-60 in just over 3 seconds and maxes out @ 150. No security bolts there either. I've other bikes putting out way more than a BSA through standard of-the-same-period rims and tyres (run at standard 20psi) and never had a tyre creep.
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Online Rex

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Re: Rim lock. Yes or no?
« Reply #7 on: 17.09. 2022 22:09 »
Well, maybe so or maybe not, but that was the reasoning of the time. Do any modern bikes have them fitted? I doubt it, given modern tubeless tyres and modern tyre technology, but that's not relevant to the thinking decades ago.

Didn't the OP's bike have them fitted?

Offline Black Sheep

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Re: Rim lock. Yes or no?
« Reply #8 on: 17.09. 2022 22:20 »
I have known a couple riding a Velo that had a rear tyre blow out and without a security bolt the tyre came off the rim and jammed on the swinging arm. They both had a long spell in hospital. It's a very rare occurrence but it can happen.
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Offline Jules

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Re: Rim lock. Yes or no?
« Reply #9 on: 18.09. 2022 02:09 »
the frequency or opportunity for the tyre coming off the rim when deflated with a tube inside would have to be very low under normal conditions, but could be exacerbated by the type and size of tyre (wider more likely), weight being carried and riding style, I have to say that I haven't come across one being used (ever!) actually........

Offline Billybream

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Re: Rim lock. Yes or no?
« Reply #10 on: 18.09. 2022 04:15 »
They left the factory fitted with tyre security  bolts, but now not necessary with advances in tyre design and manufacture.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline mark

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Re: Rim lock. Yes or no?
« Reply #11 on: 18.09. 2022 05:20 »
Thank you all for the advice. Will leave it out and keep an eye on it
Mark
1955 Road Rocket
1953 Super Flash



71 Norton Commando Roadster 750


Australia

Online Kickaha

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Re: Rim lock. Yes or no?
« Reply #12 on: 18.09. 2022 08:57 »
I have known a couple riding a Velo that had a rear tyre blow out and without a security bolt the tyre came off the rim and jammed on the swinging arm. They both had a long spell in hospital. It's a very rare occurrence but it can happen.

Unless they have two 180 degrees apart the tyre can still come off most of the way, I've seen it happen on dirt bikes
1956 BSA Gold Flash
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Online BSA_54A10

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Re: Rim lock. Yes or no?
« Reply #13 on: 18.09. 2022 16:10 »
Rim locks were necessary back in the 30' through to the 50's
WM 20's for instance have them any you would hardy call 13 Hp excessive
Their job is to prevent the tyre sliding on the rim and ripping the valve out
They will not keep a deflated tyre from coming off a rim I can vouch for that from personnal experience .
Modern tyres grip the rim substantially better than the tyres  of days gone by
My M20 tyres were originally supposed tob inflated to 18 & 20 PSI
The modern replacements are inflated to 26 & 30 PSI which is still lower then the recommended 36 but over 30 is just too hard on my butt with a rigid rear end.
The B40 OTOH does get its tyres inflated to 34 & 36 psi
For street use rim locks are no longer necessary
For scrambles & Mx they probably are as Knobbies are far more prone to walking around the rims than street tyres . 
Bike Beesa
Trevor

Offline ellis

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Re: Rim lock. Yes or no?
« Reply #14 on: 18.09. 2022 16:20 »
Rim locks on the tyres are a additional safety device so I don't go out without them.

ELLIS