|
|
|
Thread Tools | Display Modes |
Ads |
#12
|
|||
|
|||
Valve core thread dimensions
In article ,
Luns Tee wrote: Presta main - m6-0.75 Presta cap - m5-1.0 I don't believe these threads are correct. The presta valves I've measured have inch-based thread pitches - 32 and 24 tpi respectively. I don't believe I should continue to trust my memory. I remember being surprised with what the threads turned out to be, and it involving inch pitches, but extrapolated that too far. The main shaft threads are indeed metric, although it's a 0.8mm pitch rather than 0.75. My surprise was with the cap threads, which on looking at them again, still seem to be 24tpi to me. With only three thread crests at most, it's very hard to discern a difference between 24tpi and 25.4tpi, but this just highlights how unimportant the matter is. Trying to determine the gauge by looking at thread crests is misleading, as the final turns are truncated, making the apparant crests closer spaced than the actual pitch. Comparing against a 1.0mm reference, the crests appear to match, and the threads seem to fit, but on the valves I checked, contact is on the flanks of the outermost turns of thread, with the middle turn making no contact at all, and crests not reaching the thread root. The orientation of the contact indicates the thread is a coarser pitch than 1.0mm. Putting a 24tpi gauge against the cap threads, the gauge's crests land consistently in the valve's thread roots. -Luns |
#13
|
|||
|
|||
Valve core thread dimensions
|
#14
|
|||
|
|||
Valve core thread dimensions
Schrader valve
External thread: 5/16x32 fine thread Internal thread: 0.209 in OD x 36 TPI Presta valve The valve threads for Presta valves follow the ISO 4570 standard.[4][5]Â*The external threads at the tip of both "threaded" and "unthreaded" Presta valves are 5V2, which measures out to 5.2×1.058Â*mm.[6]Â*The external threads on the main body of "threaded" Presta valves are 6V1, which measures 6×0.80 |
#15
|
|||
|
|||
Valve core thread dimensions
Whoa! Blast from the past! Whatever happened to Carl Fogel?
|
#16
|
|||
|
|||
Valve core thread dimensions
On 1/3/2018 7:47 PM, Earls61 wrote:
Whoa! Blast from the past! Whatever happened to Carl Fogel? I don't know, but I miss him. -- - Frank Krygowski |
#17
|
|||
|
|||
Valve core thread dimensions
|
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
GOOD for Your CORE ? | trailguy | Unicycling | 23 | March 10th 07 08:11 AM |
schraeder valve thread? | A Muzi | Techniques | 5 | March 21st 04 10:15 PM |
Tyre suddenly leaks air at valve. HELP! | gkmac | Unicycling | 5 | December 16th 03 10:20 PM |
"Liquid Drive" bike prototype at auction | Chalo | Techniques | 87 | December 3rd 03 05:41 AM |
Valve Extender Woes | Justin F. Knotzke | Techniques | 8 | August 19th 03 03:19 PM |