H: Hubs, Wheels and Tyres Security bolt (rim lock) position in wheel

GBewley

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I have been installing these with the security bolt leading the valve stem when the wheel is rotated forward, as Mr. Richardson states in the text of "Vincent Motorcycles." The other day I noticed that the accompanying photograph shows the valve stem leading the security bolt.

Any thoughts as to which is correct, folks?

Thanks,

Glenn
 

erik

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AS you know you can turn the rear wheel to alter the secundary drive ratio.Therefore it is on you which way you mount the wheel.I would recommend to leave this part away and this better for the tube and to my mind more save to avoid an inner puncture.I had this security bolts on my Commando and the Triumph Bonneville and on my Rapide.All live now in the same place,the bin.Best regards Erik
 

GBewley

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Yes, I understand a sizeable number of Vincent riders choose to not run the security bolts, but this of course was not really the question I had asked.

Thanks,

Glenn

AS you know you can turn the rear wheel to alter the secundary drive ratio.Therefore it is on you which way you mount the wheel.I would recommend to leave this part away and this better for the tube and to my mind more save to avoid an inner puncture.I had this security bolts on my Commando and the Triumph Bonneville and on my Rapide.All live now in the same place,the bin.Best regards Erik
 

erik

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Hello Glenn! First part of my writing was the answer of your question and the second part was my opinion about it.Ignore the part you want to ignore or ignore the complete.Erik
 

vibrac

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Bolt first valve second
nowadays with H&S the real big brother reversing the wheel for a different ratio and thus reversing the tyre arrow direction (which on many ambidextrous tread patterns on our old bikes probably doesn't matter a jot) may well leave you open to problems with machine investigators in the event of an accident
With this eventuality remote as it may be in mind I have just turned the tyre round on the electric start Comet as the 19" wheel came off the alphabet twin as it morphed into an 18" racer :(
and as for security bolts I only fit em on off roaders
 

TouringGodet

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Are there any physics behind the decision on whether the security bolt should precede the valve stem, or the valve stem precede the security bolt, for a given forward rotation of the tire? What difference does it make?
 

GBewley

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Good question, Steve. I think it may have to do with the distance to the stem one direction vs. the other, the longer possibly allowing for a greater cumulative slip? Just a thought, and not one I’ve spent a lot of time exploring.


Are there any physics behind the decision on whether the security bolt should precede the valve stem, or the valve stem precede the security bolt, for a given forward rotation of the tire? What difference does it make?
 

bmetcalf

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If unknown, a concours competitor can’t get it wrong!

Also, if they prevent slip, distance of slip wouldn’t be a factor. I vote that you do it whichever is easiest.
 

kerry

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When I asked about fitting security bolts 9 out of 10 reply's said not to fit them, on my Vincent it had 3 fitted, I did end up fitting one but wish I had not, with modern rubber even on Avon SM etc I am told pressures need to be much higher than in the 50's and because of this it is apparently another reason why they are not needed. everyone can have different views of course. Kerry.
 

TouringGodet

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My possibly incorrect logic - the tube is anchored to the rim at one place, the valve stem. The tube, by design, is very flexible. If the tire moves relative to the rim, it will try to take the tube with it, tearing the valve stem out, since it can't move. So a security bolt is added, to try and anchor the tire to the rim. I can see some argument that having the security bolt 180 degrees opposite the valve stem may not be optimum. So the security bolt is placed in one of the two holes that are closest together, with the valve in the other hole. That distance is the same whether it is valve first, or security bolt first. Here is where I get confused, can't picture things in my mind. If the bike is at a standstill, and you are launching the bike, as if at a drag strip, the rim wants to immediately start turning from the force of the motor, through the drive train. But the tire does not want to move, from the friction with the pavement. That is one direction of movement between the tire and rim. But when the bike is rolling down the road at 60 MPH, and you slam on the rear brake in a panic stop (assuming a brake that can lock up the wheel), the rim stops, but the tire wants to keep moving (or skids along the pavement, either way, a force wanting to move it relative to the rim). In both scenarios, is the tire trying to move relative to the rim in the same relative direction, or in the opposite relative direction??? I can't wrap my mind around the "frame of reference".
 
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