ogre Posted March 18, 2007 Report Share Posted March 18, 2007 For those of you who're debating a front freewheel/freehub you might find this usefull.working out how many degrees it take to engage a freehub/rear freewheel (it doesn't matter for a front freewheel because you don't benefeit from the gears, it's just down to engagements,where you just divide the number of engagements into 360)divide the number of teeth you've got up front by what you've got on the rear:i.e for the standard mod gear 18/12 you'd get 1.5 (so every 360 your cranks spin when pedaling you're wheel spins 540 (360 x 1.5))times the number you get from the ratio by the number of engagements your hub/freewheel has.i.e for a profile 1.5 x 48 = 72. (the new number is bassicly the number of clicks you'de get spinning the cranks 360)divide 360 by the "new" number of engagements, the value is the most you'd have to pedal to catch an engagementi.e 360/72 = 5degreesQuick referance hubs/freewheel engagements:ACS claw 36epTensile 60epMonty 72epTryall 108epEno 72epEcho 72epHope Xc 21ep?Hope Mono 21ep?Hope Pro2 48epProfile 48epDeng freehubs 48epChris King 72ep(very bored ogre) Quote Link to comment Share on other sites More sharing options...
Netherking Posted April 2, 2007 Report Share Posted April 2, 2007 Nice Quote Link to comment Share on other sites More sharing options...
Ash-Kennard Posted April 5, 2007 Report Share Posted April 5, 2007 surely crank length would come into play somewhere? Quote Link to comment Share on other sites More sharing options...
Dan6061 Posted April 5, 2007 Report Share Posted April 5, 2007 Don't make things complicated Ash... Quote Link to comment Share on other sites More sharing options...
PaRtZ Posted April 5, 2007 Report Share Posted April 5, 2007 No it wouldn't It just means your cranks would move more before it engages. Whether you have a 2cm crank or a 200cm crank, you still have to rotate it the same amount, its just it actually moves more at the endGood post ogre, very easy to follow Quote Link to comment Share on other sites More sharing options...
ogre Posted April 22, 2007 Author Report Share Posted April 22, 2007 after ash's post about crank length for those of you who want to know how far you want to move your crank:once you've found out how many degrees your engagements are (see above)Double the your crank length (giving the equivalent of a diameter)158 = 316160 = 320165 = 330170 = 340175 = 350multiply the new value by 3.14 (Pi)158 = 316 = 992160 = 320 = 1005165 = 330 = 1036170 = 340 = 1068175 = 350 = 1099(i've kept them as whole numbers 'cause i'm lazy)now divide that number by 360 and times that by the number of degrees it takes for you to get an engagmenti.e an 175mm crank running 18-12 on a profile would move 15.26mm at most (assuming the chain is tight).and a 158mm crank running 18-12 on a profile would move 13.78mm at most (i wonder if anyone'll run shorter cranks if they knew they'd get a slightly faster engagement )happy ash? Quote Link to comment Share on other sites More sharing options...
Ash-Kennard Posted April 22, 2007 Report Share Posted April 22, 2007 christ.so i would get more power with shorter cranks? gay ive got 175, no wonder everyone can gap so bloody far Quote Link to comment Share on other sites More sharing options...
ogre Posted April 22, 2007 Author Report Share Posted April 22, 2007 christ.so i would get more power with shorter cranks? gay ive got 175, no wonder everyone can gap so bloody farno you'd feel the engagement sooner, but your gear would feel harder because you don't get as much leverage fom a shorter crank so then you'd run a lower gear and get a slower engagement anyway ffw ***! Quote Link to comment Share on other sites More sharing options...
Simpson Posted April 22, 2007 Report Share Posted April 22, 2007 lower gear and get a slower engagement anywayNo the engagment would be the same, just because you were in a lighter gear not able to gap as far? Quote Link to comment Share on other sites More sharing options...
ogre Posted April 22, 2007 Author Report Share Posted April 22, 2007 (edited) No the engagment would be the same, just because you were in a lighter gear not able to gap as far?no it wouldn't (assuming your running a freehub, if your running ffw it wouldn't make a difference) i don't think gaps come down to gearing so much as technique + and just hucking yourself. don't turn my thread into a discussion about gappping please? Edited April 22, 2007 by ogre Quote Link to comment Share on other sites More sharing options...
Davetrials Posted May 7, 2007 Report Share Posted May 7, 2007 echo free hub48 epecho freewheel72epsmashing my face on a rock cos there both so shitepriceless.. Quote Link to comment Share on other sites More sharing options...
Mark W Posted May 8, 2007 Report Share Posted May 8, 2007 christ.so i would get more power with shorter cranks? gay ive got 175, no wonder everyone can gap so bloody farNah, stick with 175s. Bosh on a harder gear, and it'll feel like your old gear with 165mm cranks, but you'll have more power. Worked OK for me on mods, got my gaps pretty decent in the end. Quote Link to comment Share on other sites More sharing options...
BONGO Posted June 29, 2007 Report Share Posted June 29, 2007 Technically, if i'm being picky, a profile hub actually only has 24 engagement points within the hub.One revolution of the hub does create 48 engagemenets, because 2 pawls engage at one point, then another 2 engage half way in between, doubling the number of engagements from 24 to 48.To look at it in terms of reliability, you could say that this means the engagments are going to be more reliable. This is becasue the space taken up on the outside surface of the inner of the hub, is only filled with 24 engagements, not 48, which means they can be double the size, making the pawls engage deeper and have more contact against the hub.In the event of a slip, there are 2 pawls waiting to engage hald an engagement away, and are more likely going to catch than a hub with more engagements, because the size of the engagements and depth, determines the strength of the spring required to push the pawls into them. Because the engagements are bigger, the springs are that little bit stronger, to push the pawl deep into the engagement. Profiles are very safe hubs for trials for these reasons, and obviously others. I don't know if any of the other systems work in this way, maybe they do.Bongo Quote Link to comment Share on other sites More sharing options...
poopipe Posted June 29, 2007 Report Share Posted June 29, 2007 I don't know if any of the other systems work in this way, maybe they do.BongoEno does, 36 teeths + 2 offset sets of 3 pawls = 72 engagements at the pedals Quote Link to comment Share on other sites More sharing options...
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