#21
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Mini Pump
On Monday, May 10, 2021 at 4:12:22 PM UTC-7, James wrote:
On 10/5/21 6:45 pm, Lou Holtman wrote: Op maandag 10 mei 2021 om 07:45:24 UTC+2 schreef James: On 10/5/21 11:50 am, Frank Krygowski wrote: It might be handy to see a chart of "pump strokes to 100 psi" for various brands and models, starting from an empty tube. Don't forget effort (force) to achieve said pressure. Diameter and length affects volume / stroke. Diameter also affects force @ pressure. To minimize force and strokes, opt for smaller diameter and longer barrel. However - is it still a "mini pump" with a long barrel? I've got a Lezyne road drive pump for my road bike with up to 25mm tyres @ 100psi, and a higher volume Lezyne pump for my gravel bike that has 42mm tyres @ 50psi. 100psi is easily achievable for the road bike, but I wouldn't want to use the larger diameter & volume gravel bike pump to reach 100psi, though it might take fewer strokes. 100 psi easily achieved with a minipump? I don't believe that. Did you ever checked that? Yes Lou. I tested it years ago, but for you I tried again. To save time I pumped my front 23mm tyre to 100psi using my Silca floor pump, then attached my Lezyne Road Drive mini pump and applied another 40 strokes. Then I reconnected my Silca floor pump and checked the pressure. It was near to 120psi. You must have strong arms -- but really short arms like a T-Rex. I think T-Rex arms would be perfect for a mini-pump. I could probably get that pressure with my Road Morph with the pump on the ground and the mini foot-peg extended, but not with my various other mini-pumps. 80-90PSI would be a big win. -- Jay Beattie. |
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#22
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Mini Pump
On Monday, May 10, 2021 at 6:29:04 PM UTC-5, jbeattie wrote:
On Monday, May 10, 2021 at 4:12:22 PM UTC-7, James wrote: On 10/5/21 6:45 pm, Lou Holtman wrote: Op maandag 10 mei 2021 om 07:45:24 UTC+2 schreef James: On 10/5/21 11:50 am, Frank Krygowski wrote: It might be handy to see a chart of "pump strokes to 100 psi" for various brands and models, starting from an empty tube. Don't forget effort (force) to achieve said pressure. Diameter and length affects volume / stroke. Diameter also affects force @ pressure. To minimize force and strokes, opt for smaller diameter and longer barrel. However - is it still a "mini pump" with a long barrel? I've got a Lezyne road drive pump for my road bike with up to 25mm tyres @ 100psi, and a higher volume Lezyne pump for my gravel bike that has 42mm tyres @ 50psi. 100psi is easily achievable for the road bike, but I wouldn't want to use the larger diameter & volume gravel bike pump to reach 100psi, though it might take fewer strokes. 100 psi easily achieved with a minipump? I don't believe that. Did you ever checked that? Yes Lou. I tested it years ago, but for you I tried again. To save time I pumped my front 23mm tyre to 100psi using my Silca floor pump, then attached my Lezyne Road Drive mini pump and applied another 40 strokes. Then I reconnected my Silca floor pump and checked the pressure. It was near to 120psi. You must have strong arms -- but really short arms like a T-Rex. I think T-Rex arms would be perfect for a mini-pump. I could probably get that pressure with my Road Morph with the pump on the ground and the mini foot-peg extended, but not with my various other mini-pumps. 80-90PSI would be a big win. -- Jay Beattie. You got one set of strong arms............the deacon not so blessed. Deacon mark |
#23
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Mini Pump
On 5/10/2021 6:12 PM, James wrote:
On 10/5/21 6:45 pm, Lou Holtman wrote: Op maandag 10 mei 2021 om 07:45:24 UTC+2 schreef James: On 10/5/21 11:50 am, Frank Krygowski wrote: It might be handy to see a chart of "pump strokes to 100 psi" for various brands and models, starting from an empty tube. Don't forget effort (force) to achieve said pressure. Diameter and length affects volume / stroke. Diameter also affects force @ pressure. To minimize force and strokes, opt for smaller diameter and longer barrel. However - is it still a "mini pump" with a long barrel? I've got a Lezyne road drive pump for my road bike with up to 25mm tyres @ 100psi, and a higher volume Lezyne pump for my gravel bike that has 42mm tyres @ 50psi. 100psi is easily achievable for the road bike, but I wouldn't want to use the larger diameter & volume gravel bike pump to reach 100psi, though it might take fewer strokes. 100 psi easily achieved with a minipump? I don't believe that. Did you ever checked that? Yes Lou. I tested it years ago, but for you I tried again. To save time I pumped my front 23mm tyre to 100psi using my Silca floor pump, then attached my Lezyne Road Drive mini pump and applied another 40 strokes. Then I reconnected my Silca floor pump and checked the pressure. It was near to 120psi. The manufacturer humbly notes that this is the best product humans have ever made: https://ride.lezyne.com/products/1-mp-rddr-v2l04 But under 'specs' doesn't list the piston diameter which is the crucial dimension. A one-square-inch piston (1-1/4" dia) needs 100 lbs of muscle to make 100psi. A half-inch diameter needs about 20 pounds (and 5x number of strokes if the length is the same) -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#24
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Mini Pump
On 5/10/2021 8:50 PM, AMuzi wrote:
On 5/10/2021 6:12 PM, James wrote: On 10/5/21 6:45 pm, Lou Holtman wrote: Op maandag 10 mei 2021 om 07:45:24 UTC+2 schreef James: On 10/5/21 11:50 am, Frank Krygowski wrote: It might be handy to see a chart of "pump strokes to 100 psi" for various brands and models, starting from an empty tube. Don't forget effort (force) to achieve said pressure. Diameter and length affects volume / stroke. Diameter also affects force @ pressure. To minimize force and strokes, opt for smaller diameter and longer barrel. However - is it still a "mini pump" with a long barrel? I've got a Lezyne road drive pump for my road bike with up to 25mm tyres @ 100psi, and a higher volume Lezyne pump for my gravel bike that has 42mm tyres @ 50psi. 100psi is easily achievable for the road bike, but I wouldn't want to use the larger diameter & volume gravel bike pump to reach 100psi, though it might take fewer strokes. 100 psi easily achieved with a minipump? I don't believe that. Did you ever checked that? Yes Lou.Â* I tested it years ago, but for you I tried again. To save time I pumped my front 23mm tyre to 100psi using my Silca floor pump, then attached my Lezyne Road Drive mini pump and applied another 40 strokes.Â* Then I reconnected my Silca floor pump and checked the pressure.Â* It was near to 120psi. The manufacturer humbly notes that this is the best product humans have ever made: https://ride.lezyne.com/products/1-mp-rddr-v2l04 But under 'specs' doesn't list the piston diameter which is the crucial dimension. Also doesn't list the number of strokes to fill a typical tire to 100 psi. Again, that should be standard info. A one-square-inch piston (1-1/4" dia) needs 100 lbs of muscle to make 100psi. A half-inch diameter needs about 20 pounds (and 5x number of strokes if the length is the same) -- - Frank Krygowski |
#25
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Mini Pump
On 11/5/21 9:29 am, jbeattie wrote:
On Monday, May 10, 2021 at 4:12:22 PM UTC-7, James wrote: On 10/5/21 6:45 pm, Lou Holtman wrote: 100 psi easily achieved with a minipump? I don't believe that. Did you ever checked that? Yes Lou. I tested it years ago, but for you I tried again. To save time I pumped my front 23mm tyre to 100psi using my Silca floor pump, then attached my Lezyne Road Drive mini pump and applied another 40 strokes. Then I reconnected my Silca floor pump and checked the pressure. It was near to 120psi. You must have strong arms -- but really short arms like a T-Rex. I think T-Rex arms would be perfect for a mini-pump. I could probably get that pressure with my Road Morph with the pump on the ground and the mini foot-peg extended, but not with my various other mini-pumps. 80-90PSI would be a big win. I stand about 190cm tall and my arm span is similar if not more. So no, I don't have short arms. I'm not very bulky either, at about 75kg. I don't think my arms are very strong. I certainly can't do many pushups. Maybe 10? I read somewhere that the road drive is 17mm dia. Maybe the internal dia is 15mm? That is about 177mm^2. 100psi is 689476 Pa, which is Newtons / m^2. Converting to N / 177mm^2 is 121.84N, or 12.4kg of force to achieve 100psi. I can't be bothered going out to measure precisely, but I think my calcs are in the ball park. I'd be happy for someone to verify. Frank? -- JS |
#26
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Mini Pump
On 11/5/21 12:26 pm, James wrote:
On 11/5/21 9:29 am, jbeattie wrote: On Monday, May 10, 2021 at 4:12:22 PM UTC-7, James wrote: On 10/5/21 6:45 pm, Lou Holtman wrote: 100 psi easily achieved with a minipump? I don't believe that. Did you ever checked that? Yes Lou. I tested it years ago, but for you I tried again. To save time I pumped my front 23mm tyre to 100psi using my Silca floor pump, then attached my Lezyne Road Drive mini pump and applied another 40 strokes. Then I reconnected my Silca floor pump and checked the pressure. It was near to 120psi. You must have strong arms -- but really short arms like a T-Rex.Â* I think T-Rex arms would be perfect for a mini-pump. I could probably get that pressure with my Road Morph with the pump on the ground and the mini foot-peg extended,Â* but not with my various other mini-pumps.Â* 80-90PSI would be a big win. I stand about 190cm tall and my arm span is similar if not more.Â* So no, I don't have short arms.Â* I'm not very bulky either, at about 75kg. I don't think my arms are very strong.Â* I certainly can't do many pushups.Â* Maybe 10? I read somewhere that the road drive is 17mm dia.Â* Maybe the internal dia is 15mm?Â* That is about 177mm^2.Â* 100psi is 689476 Pa, which is Newtons / m^2.Â* Converting to N / 177mm^2 is 121.84N, or 12.4kg of force to achieve 100psi. I can't be bothered going out to measure precisely, but I think my calcs are in the ball park.Â* I'd be happy for someone to verify.Â* Frank? Ok, after Andrew's post I did measure. The bore/piston diameter is damn close to 17mm. That means my previous calc needs to be modified a little. The force comes to 16kg. -- JS |
#27
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Mini Pump
On 11/5/21 12:04 pm, Frank Krygowski wrote:
Also doesn't list the number of strokes to fill a typical tire to 100 psi. Again, that should be standard info. Define "typical". -- JS |
#28
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Mini Pump
On Monday, May 10, 2021 at 10:49:36 PM UTC-4, James wrote:
On 11/5/21 12:04 pm, Frank Krygowski wrote: Also doesn't list the number of strokes to fill a typical tire to 100 psi. Again, that should be standard info. Define "typical". What I use, obviously! ;-) More seriously, the definition wouldn't matter much as long as it was used consistently for comparing a variety of pumps. What's the volume of (say) a 25mm tire? Maybe 67 in^3 or 1100 cubic centimeters? Use a rigid tank of that volume fitted with a schrader and a presta valve. - Frank Krygowski |
#29
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Mini Pump
Op dinsdag 11 mei 2021 om 01:12:22 UTC+2 schreef James:
On 10/5/21 6:45 pm, Lou Holtman wrote: Op maandag 10 mei 2021 om 07:45:24 UTC+2 schreef James: On 10/5/21 11:50 am, Frank Krygowski wrote: It might be handy to see a chart of "pump strokes to 100 psi" for various brands and models, starting from an empty tube. Don't forget effort (force) to achieve said pressure. Diameter and length affects volume / stroke. Diameter also affects force @ pressure. To minimize force and strokes, opt for smaller diameter and longer barrel. However - is it still a "mini pump" with a long barrel? I've got a Lezyne road drive pump for my road bike with up to 25mm tyres @ 100psi, and a higher volume Lezyne pump for my gravel bike that has 42mm tyres @ 50psi. 100psi is easily achievable for the road bike, but I wouldn't want to use the larger diameter & volume gravel bike pump to reach 100psi, though it might take fewer strokes. 100 psi easily achieved with a minipump? I don't believe that. Did you ever checked that? Yes Lou. I tested it years ago, but for you I tried again. To save time I pumped my front 23mm tyre to 100psi using my Silca floor pump, then attached my Lezyne Road Drive mini pump and applied another 40 strokes. Then I reconnected my Silca floor pump and checked the pressure. It was near to 120psi. -- JS That is impressive. Lou |
#30
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Mini Pump
On 5/10/2021 9:26 PM, James wrote:
On 11/5/21 9:29 am, jbeattie wrote: On Monday, May 10, 2021 at 4:12:22 PM UTC-7, James wrote: On 10/5/21 6:45 pm, Lou Holtman wrote: 100 psi easily achieved with a minipump? I don't believe that. Did you ever checked that? Yes Lou. I tested it years ago, but for you I tried again. To save time I pumped my front 23mm tyre to 100psi using my Silca floor pump, then attached my Lezyne Road Drive mini pump and applied another 40 strokes. Then I reconnected my Silca floor pump and checked the pressure. It was near to 120psi. You must have strong arms -- but really short arms like a T-Rex. I think T-Rex arms would be perfect for a mini-pump. I could probably get that pressure with my Road Morph with the pump on the ground and the mini foot-peg extended, but not with my various other mini-pumps. 80-90PSI would be a big win. I stand about 190cm tall and my arm span is similar if not more. So no, I don't have short arms. I'm not very bulky either, at about 75kg. I don't think my arms are very strong. I certainly can't do many pushups. Maybe 10? I read somewhere that the road drive is 17mm dia. Maybe the internal dia is 15mm? That is about 177mm^2. 100psi is 689476 Pa, which is Newtons / m^2. Converting to N / 177mm^2 is 121.84N, or 12.4kg of force to achieve 100psi. I can't be bothered going out to measure precisely, but I think my calcs are in the ball park. I'd be happy for someone to verify. Frank? Probably close enough, considering your report of 'not extreme effort'. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
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