Happy Valley
Active Member
Yes, number of discussions on concave spindle in archives that have come up. The necessary deflection in the pneumatic profile of the tire created by the spindle seems to rule out anything but a straight roller.
Whinning Tire Noise From Friction Drives
- Thread starter Porkchop
- Start date
graucho
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- Feb 14, 2008
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Lou sure Knows what he's talking about with friction roller ratios. Gave me some friction pointers and he turned me towards this affordable tire a year ago and I have a ton of miles on it. (removed the speedo so not sure exactly how many) http://www.biketiresdirect.com/piksct/innova_swiftor_city_tire/pp.htm I liked the ride of this tire so much I installed them on the front and back on my GEBE belt drive also.
If I remember correctly the only problem Lou had was when he hit the brakes super hard and wore a patch where it meet the tar. (but he says he's a big guy
)
If I remember correctly the only problem Lou had was when he hit the brakes super hard and wore a patch where it meet the tar. (but he says he's a big guy
)
Last edited:
Pirate88179
Member
Graucho:
Man!!! What a beautiful chopper and excellent slide show!! I got to watch that bike take shape before my eyes. What a work of art. What motor did you use and how does it ride???? Very nice.
Bill
Man!!! What a beautiful chopper and excellent slide show!! I got to watch that bike take shape before my eyes. What a work of art. What motor did you use and how does it ride???? Very nice.
Bill
graucho
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Thanks Bill, but we need to keep the tread on topic. I'll PM you.
loquin
Well-Known Member
Bill, was the pulley crowned, or concave? The one's I'm familiar with, used on old farm tractors/equipment are slightly crowned (larger diameter in the center of the pulley) to keep the flat belt centered.
I believe, with those flat belts on the crowned pulleys, that the belt stretches a bit in the middle, (which is where the bulk of the pressure, and torque, is transferred) and there's very little (comparatively) pressure on the outside part of the belt... so, it slips a bit there. Also, with a small curvature, there's not much tangential speed difference.
I believe, with those flat belts on the crowned pulleys, that the belt stretches a bit in the middle, (which is where the bulk of the pressure, and torque, is transferred) and there's very little (comparatively) pressure on the outside part of the belt... so, it slips a bit there. Also, with a small curvature, there's not much tangential speed difference.
Pirate88179
Member
Lou:
Same idea with the farm equipment I suppose...this was convex with a very large radius, somewhere in the neighborhood of 8" or more. The diameter was around 1". There was quite a difference in the diameters of the outside edges and the high center.
Yes, I agree the belt flexed and "formed" a bit to the curved shape but it also had contact with the much smaller diameter outside edges as well. We used that machine everyday for 3 shifts and had to replace that belt maybe about once per year. This is what has confused me. Now, I realize that shape was there for a reason. It was designed to keep the belt centered and on that drive roller at very high rpms. And, it worked. At the speeds used, and if you could have ever heard this thing, any slippage at all would have destroyed that belt in less than a few minutes.
So, I still agree with you anyway, I just can't figure out the difference. But, as I said earlier, it does not matter really as the MB application is different as the tire forms a relatively flat surface for the contact area. Sometimes, I think too much, ha ha.
Bill
Same idea with the farm equipment I suppose...this was convex with a very large radius, somewhere in the neighborhood of 8" or more. The diameter was around 1". There was quite a difference in the diameters of the outside edges and the high center.
Yes, I agree the belt flexed and "formed" a bit to the curved shape but it also had contact with the much smaller diameter outside edges as well. We used that machine everyday for 3 shifts and had to replace that belt maybe about once per year. This is what has confused me. Now, I realize that shape was there for a reason. It was designed to keep the belt centered and on that drive roller at very high rpms. And, it worked. At the speeds used, and if you could have ever heard this thing, any slippage at all would have destroyed that belt in less than a few minutes.
So, I still agree with you anyway, I just can't figure out the difference. But, as I said earlier, it does not matter really as the MB application is different as the tire forms a relatively flat surface for the contact area. Sometimes, I think too much, ha ha.
Bill
