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Drilling cranks for Dual holes

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  • #16
    Thanks, that makes sense. I doubt that Garry has one of those tap guide things in his shop but we might be able to make one.

    I thought that I would have time to do this by the time I am done work (today) but looks like I will have to do it when I get back from BC (in a month)
    My friends, love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful and optimistic. And we値l change the world. - Jack Layton

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    • #17
      Originally posted by maestro8 View Post
      I've used the taps to cut new threads before, but I wouldn't recommend doing so "free-hand". These taps only have a few threads of taper, so it's not so easy to line up. If you use the taps in the drill press / mill (with a live center) immediately after drilling the hole, you're good to go.
      So I tapped one set of cranks today, and like an idiot thought "this looks strait" and just tapped freehand thinking for some reason that if I was off it would follow the hole and straiten out. By the time it was through the crank and I had a look at the threads I realized that I was a little bit off.

      lined the next one up on the drill press, stuck a little bit in there to center the back of the tap and it was much straiter the second time.

      Threw them on the new 36 to see how they rode. Incredibly smooth ride at that length but the left pedal is noticeably crooked. I might try using a heli-coil to fix it or I might just throw these on the trials and try again.
      My friends, love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful and optimistic. And we値l change the world. - Jack Layton

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      • #18
        The second hole was for 110mm? I'd definitely use the heli-coil (or the other hole) before the crooked pedal causes knee problems...

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        • #19
          I decided to aim for 114, my initial drill bit wandered a bit at the start so I ended up going with 113mm.

          I drilled the first one from the top which i think has an extra layer of hardness and is a much more sloped surface than going from the bottom. I went from the bottom for the second crank and was able to match the position of the first.
          My friends, love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful and optimistic. And we値l change the world. - Jack Layton

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          • #20
            Kris Holm Crank Sizes

            Why doesn't Kris Holm sell his nice cranks with a few more dual-hole combinations? It seems like they are deficient in the shorter sizes. Here are a few suggestions:

            114/150

            110/137

            If Kris decided to add another dual-hole crank, what would be most popular?

            Scott

            (Kris, are you listening?)

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            • #21
              I think the sizes that Kris has now are sufficient.

              What would be more useful is for Nimbus to make some dual hole square taper cranks (I don't expect Kris to, as all his products are ISIS based now).
              -James

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              • #22
                I messed up the threads on the one side but love the 137/114 combo I made.

                The park taps cut fine with a 1/2" hole.
                My friends, love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful and optimistic. And we値l change the world. - Jack Layton

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                • #23
                  http://www.ebikestop.com/ride2_crank...rms-CR8870.php

                  hey, I stumbled on this little find today, it's a pricey solution to different crank sizes, and it would raise the Q factor quite a bit, but boy, look at all those beautiful options

                  also, it looks like you could make one pretty easily if you wanted to switch it around quite a bit.

                  anybody used these things? I wonder how they would take to a unicyclist's abuse
                  Steel is real! => I ride a Nimbus!

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                  • #24
                    109/127/150mm Cranks

                    This is an older thread but the info is still good. Today I added a third hole on my 127/150mm KH Spirit cranks. I now have 109/127/150mm cranks. I've been riding the 36er with 127/150mm cranks in the 127mm hole for a couple years and thousands of miles. I wanted to try shorter cranks for level road riding so I add the third 109mm hole on my cranks.



                    More pics and details here.

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                    • #25
                      Originally posted by JimT View Post
                      This is an older thread but the info is still good. Today I added a third hole on my 127/150mm KH Spirit cranks. I now have 109/127/150mm cranks. I've been riding the 36er with 127/150mm cranks in the 127mm hole for a couple years and thousands of miles. I wanted to try shorter cranks for level road riding so I add the third 109mm hole on my cranks.
                      And now the important question. How does it feel/compare with 127 to you?

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                      • #26
                        such a pity you need to get off the uni and spend 10 mins to "change gear"

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                        • #27
                          Jim, That is fantastic! your pictures would make a great "how to" for anyone interested in doing a similar project and it looks like you avoided all the silly mistakes that I made.

                          Well done sir!


                          As for taking 10 minutes to change gear... really it should take less than a minute. Much faster than swapping out cranks
                          My friends, love is better than anger. Hope is better than fear. Optimism is better than despair. So let us be loving, hopeful and optimistic. And we値l change the world. - Jack Layton

                          Comment


                          • #28
                            Originally posted by saskatchewanian View Post
                            Jim, That is fantastic! your pictures would make a great "how to" for anyone interested in doing a similar project and it looks like you avoided all the silly mistakes that I made.

                            Well done sir!


                            As for taking 10 minutes to change gear... really it should take less than a minute. Much faster than swapping out cranks
                            I did same some years ago (110/127/150) as Kris didn稚 want to make them
                            http://monocycle.info
                            http://www.leblogdumonocycle.fr/
                            CITY XTP 26", MUNI KH26" & KH29", ROAD Oracle 32" and KH36"
                            my goal : a 3 geared 29" to have only one uni for all kind of rides :-)

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                            • #29
                              Originally posted by ruari View Post
                              And now the important question. How does it feel/compare with 127 to you?
                              I've put about 20 miles around the neighborhood on the 109mm cranks. I've only rode the 36er with 127mm in the past. Compared to the 127's the 109's are definitely faster but do require more pressure on the pedals, especially on hills and rough ground. I guess that my cursing speed increased about 10% and my all time fastest speed has increased too. On the road I can pull a 12% grade with no problem and shorter runs up to 17%. Free mounting is not a problem but does benefit from a slight adjustment in timing for a rolling mount.

                              I think for flat, smooth and long runs it is worth moving from 127 to 109mm. The 109's also have an added training benefit, I can put more of a load/workout on my legs in a shorter time with the shorter cranks. On very long rides I would guess that moving from shorter to longer cranks may be needed when I start to get tried.

                              I've never tried the 150mm position, maybe I should do that sometime. I also did not change my seat height when I changed crank length, I might try that too.

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                              • #30
                                Originally posted by JimT View Post
                                ... my cursing speed increased about 10% ...
                                Great! I always wanted to increase my cursing speed.
                                Wo is zweite Rad?

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