Out yesterday for an afternoon loosening up ride, it clouded over and tipped down with rain. I stopped at some friends to natter and dry out a smidgen.
When I restarted my ride my dynamo, which had been working perfectly in the peeing rain, started to slip. Once I'd gone down the road a bit and pushed the dynamo onto the tyre a bit by hand, all was well.
However I found I could get it to slip again by pedalling out of the saddle. I can't work out the mechanism for this. The dynamo is well aligned and mounted on the rear of the front fork, such that it tends to be dragged into the tyre. Why would standing up, with more weight over the front wheel cause it to slip?
"Tim Hall" <[email hidden]> wrote in message "]news:[email hidden]...
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Out yesterday for an afternoon loosening up ride, it clouded over and tipped down with rain. I stopped at some friends to natter and dry out a smidgen.
When I restarted my ride my dynamo, which had been working perfectly in the peeing rain, started to slip. Once I'd gone down the road a bit and pushed the dynamo onto the tyre a bit by hand, all was well.
However I found I could get it to slip again by pedalling out of the saddle. I can't work out the mechanism for this. The dynamo is well aligned and mounted on the rear of the front fork, such that it tends to be dragged into the tyre. Why would standing up, with more weight over the front wheel cause it to slip?
I would guess you have a bit of frame flex. Standing up puts weight forward and may slightly misalign the rear wheel.
"Ric" <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
Quoted message said:
aligned and mounted on the rear of the front fork, such that it tends to be dragged into the tyre. Why would standing up, with more weight over the front wheel cause it to slip?
I would guess you have a bit of frame flex. Standing up puts weight
forward
Quoted message said:
and may slightly misalign the rear wheel.
I had a similar problem. The key problem turned out that the dynamo was not firmly clamped to the frame. Therefore frame flex or a misplaced boot (it was a bit close to my heal) moved the whole shooting match round the tube and so (in my case) on to the wheel (causing things to light up in the daytime). It needed almost continuous tweaking until I got rid of the damn thing (it was a cheap & very nasty).
When I restarted my ride my dynamo, which had been working perfectly in the peeing rain, started to slip. Once I'd gone down the road a bit and pushed the dynamo onto the tyre a bit by hand, all was well.
However I found I could get it to slip again by pedalling out of the saddle. I can't work out the mechanism for this. The dynamo is well aligned and mounted on the rear of the front fork, such that it tends to be dragged into the tyre. Why would standing up, with more weight over the front wheel cause it to slip?
I would suggest it is a combination of the wheel flexing when you put more weight on the front as you stand up - as other people have said - along with the slight but sudden acceleration that will occur. This sudden acceleration may over come the static friction of the roller on the tyre. With sliding friction being less than static friction, as soon as it starts to slip, it is a b****r to stop.
I have three dynamo bottles, all identical apart from the fact that one slips almost constanly on any bike no matter how I set it up.
John T. Remove the singers of Spam before replying
I would suggest it is a combination of the wheel flexing when you put more weight on the front as you stand up - as other people have said - along with the slight but sudden acceleration that will occur.
Wow - I had a look this morning and I was surprised by how much the wheel does flex when you get out of the saddle. My dynamo is mounted on the front using a dynoshoe, so I can see the gap between the roller and the wheel and it changes by 2 to 3 mm.
John T. Remove the singers of Spam before replying
Wow - I had a look this morning and I was surprised by how much the wheel does flex when you get out of the saddle. My dynamo is mounted on the front using a dynoshoe, so I can see the gap between the roller and the wheel and it changes by 2 to 3 mm.
This is Not A Surprise. Slipping rollers is one of the reasons I decided early on to go for hub dynamos.
