Here's the question which was posed in last month's "The Engineer", and which I posted to RBT for the amusement and delight of the patrons here.
"Stan the cyclist is keen to stay abreast of latest developments so purchased a hi-tech carbon fibre rear wheel with 16 radial spokes equally spaced and alternating eight to each side of the hub. The wheel builder has centred the rim and trued the wheel and then torqued up the spokes to give a tension of 125kg (sic) per spoke. As Stan lowers his 75kg onto the saddle he wonders what the tension is in the spokes now.
Well the proposed answer has now been printed:
"The load in the spokes does not change until the imposed load exceeds the preload - so as the cyclist weighs less than the preload, the spokes remain tensioned to 125kg".
This doesn't add up as far as I can see - perhaps "The Engineer"'s letters page has been a bit slow lately...
Here's the question which was posed in last month's "The Engineer", and which I posted to RBT for the amusement and delight of the patrons here.
"Stan the cyclist is keen to stay abreast of latest developments so purchased a hi-tech carbon fibre rear wheel with 16 radial spokes equally spaced and alternating eight to each side of the hub. The wheel builder has centred the rim and trued the wheel and then torqued up the spokes to give a tension of 125kg (sic) per spoke. As Stan lowers his 75kg onto the saddle he wonders what the tension is in the spokes now.
Well the proposed answer has now been printed:
"The load in the spokes does not change until the imposed load exceeds the preload - so as the cyclist weighs less than the preload, the spokes remain tensioned to 125kg".
This doesn't add up as far as I can see - perhaps "The Engineer"'s letters page has been a bit slow lately...
Vic.
Of course the spokes have no more preload - if you're been following alt.mountain-bike's thread on damped suspension, you'll realize that bikers do indeed fly 😉
Here's the question which was posed in last month's "The Engineer", and which I posted to RBT for the amusement and delight of the patrons here.
"Stan the cyclist is keen to stay abreast of latest developments so purchased a hi-tech carbon fibre rear wheel with 16 radial spokes equally spaced and alternating eight to each side of the hub. The wheel builder has centred the rim and trued the wheel and then torqued up the spokes to give a tension of 125kg (sic) per spoke. As Stan lowers his 75kg onto the saddle he wonders what the tension is in the spokes now.
Well the proposed answer has now been printed:
"The load in the spokes does not change until the imposed load exceeds the preload - so as the cyclist weighs less than the preload, the spokes remain tensioned to 125kg".
This doesn't add up as far as I can see - perhaps "The Engineer"'s letters page has been a bit slow lately...
Vic.
Of course the spokes have no more **preload**
Er, tension. And no more or less... yeah, its 4AM, I'm going to bed.
Quoted message said:
- if you're been following alt.mountain-bike's thread on damped suspension, you'll realize that bikers do indeed fly 😉
Well I think that Stan's a sap for buying a wheel with no crossed spokes in the rear and no dish.
Todd H.
Quoted message said:
Vic said:
Here's the question which was posed in last month's "The Engineer", and which I posted to RBT for the amusement and delight of the patrons here.
"Stan the cyclist is keen to stay abreast of latest developments so purchased a hi-tech carbon fibre rear wheel with 16 radial spokes equally spaced and alternating eight to each side of the hub. The wheel builder has centred the rim and trued the wheel and then torqued up the spokes to give a tension of 125kg (sic) per spoke. As Stan lowers his 75kg onto the saddle he wonders what the tension is in the spokes now.
Well the proposed answer has now been printed:
"The load in the spokes does not change until the imposed load exceeds the preload - so as the cyclist weighs less than the preload, the spokes remain tensioned to 125kg".
This doesn't add up as far as I can see - perhaps "The Engineer"'s letters page has been a bit slow lately...
Lot of variable, more than were given in the problem statement I think.
Why not do the experiment and measure the change in spoke tension? Would the change vary depending on the relative stiffness of the rim and spokes?
I have a used Wheelsmith tensiometer, but I didn't get the calibration chart. Anyone have one? Even if it's off, the change might show something...
[email hidden] (Todd Holland) wrote in message news:<[email hidden]>...
Quoted message said:
Well I think that Stan's a sap for buying a wheel with no crossed spokes in the rear and no dish.
Todd H.
Quoted message said:
Vic said:
Here's the question which was posed in last month's "The Engineer", and which I posted to RBT for the amusement and delight of the patrons here.
"Stan the cyclist is keen to stay abreast of latest developments so purchased a hi-tech carbon fibre rear wheel with 16 radial spokes equally spaced and alternating eight to each side of the hub. The wheel builder has centred the rim and trued the wheel and then torqued up the spokes to give a tension of 125kg (sic) per spoke. As Stan lowers his 75kg onto the saddle he wonders what the tension is in the spokes now.
Well the proposed answer has now been printed:
"The load in the spokes does not change until the imposed load exceeds the preload - so as the cyclist weighs less than the preload, the spokes remain tensioned to 125kg".
This doesn't add up as far as I can see - perhaps "The Engineer"'s letters page has been a bit slow lately...
Lot of variable, more than were given in the problem statement I think.
Why not do the experiment and measure the change in spoke tension? Would the change vary depending on the relative stiffness of the rim and spokes?
I have a used Wheelsmith tensiometer, but I didn't get the calibration chart. Anyone have one? Even if it's off, the change might show something...
won't help, they are for each tool. and the actual reading depends on what type spoke you use it on. anything between ~ 40 and 80 is 'good' - it depends.
[email hidden] (Vic) wrote in message news:<[email hidden]>...
Quoted message said:
"The load in the spokes does not change until the imposed load exceeds the preload - so as the cyclist weighs less than the preload, the spokes remain tensioned to 125kg".
The "model" answer is so strange that I'm wondering if something has been missed both from it and the question. Possibly the question was meant to be: what happens to the tension in the uppermost spokes?
