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Q-Factor Bosch

Discussion in 'Technical & FAQ' started by Deere John, Jan 11, 2017.

  1.  
    Deere John

    Deere John Pedelecer

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    Just curious, what is your q-factor on your Bosch crank?

    I have a fatbike with Performance CX and have about 246mm! Kind of much!? Don't know.

    [​IMG]

    (easy to measure if you measure one side to the centre of the tube, turn the crank and measure other side, add together, should be same on each side I think)
     
  2.  
    Deere John

    Deere John Pedelecer

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    Ok, I ordered some cranks to try and find a more straight one, but it was difficult...

    First I have to show you the distance between the crank and chainstay. It is about 17mm as you see. That would mean I can easily fit a crank which is more straight, I feel it would not have to be more than maybe 5mm space there.

    Crank distance.jpg

    So I took off my crank and measured the curve, from bottom to inner edge, as on photo. It was about 58mm (on this side (R), the other side was 55mm). (It is branded "Miranda" btw).

    Crank measure.jpg

    Well, the other three cranks was all more straight (and same measure on each side), here is the numbers:

    Haibike Xduro Fatsix original: 58mm (55mm)
    FSA Metropolis CK-632/IS: 26mm
    FSA Metropolis AL-8/IS: 35mm
    FSA 745/IS: 26mm

    Cranks (top).jpg Cranks (side).jpg

    It would have to be like 45mm or something, the AL-8 came closest but still too far away to be used :(

    And, as you might see, my original crank was stucked and I stripped the threads so I had to pull it out with a big tool, so, now I don't have any crank at all).

    So, I'm in deep **** now, anyone have some crank that have about 45mm if you measure like I did there? (or maybe it's easier to measure from top to top or something if it's on the bike).

    /edit: I found one that have 49mm there, see below. Miranda Delta 0.
     
    #2 Deere John, Mar 5, 2017
    Last edited: Mar 5, 2017
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    soundwave

    soundwave Pedelecer

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  4.  
    Deere John

    Deere John Pedelecer

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    Soundwave! Thanks for that. I think we found that website simustaneously. I was looking at the back side of my crank and it said "Miranda" so I was looking there...

    It looks like the "Gamma 0" model (looks 99% correct), but couldn't find the right measurements there, but the "Delta 0" model has the EXACT numbers even though it doesn't look the same really.

    Miranda Delta 0 version 55Q-35 (Stock).png

    They have a Q-factor choice for each crank, so I found out that the one named "55Q:29.6" is what I should need here, looks like this:

    Miranda Delta 0 version 55Q-29.6 (Wanted).png

    That gains about 5.5mm on each side. They have one "55Q:21" also but that would be 14mm less and that's too much I think, don't feel like chansing.

    So... they have a store where I ordered the Delta 0 standard black version 175mm/ISIS but you couldn't chose the Q-factor so I added a message to the order and hope they can send me the right one. It costs 60 Euro with shipping 10 Euro. Quite ok I think!

    Really glad I found this! Hope it works.

    Btw. That page was crank heaven!!! If you need a new crank, go there, I'm sure you'll find it.
     
  5.  
    Deere John

    Deere John Pedelecer

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    Got them now! Serious stuff this.

    Miranda cranks 01 box.jpg Miranda cranks 02 unboxing.jpg

    They look a little cleaner than my old ones, couldn't find them now but here is the new ones:

    Miranda cranks 03 photo.jpg

    And, when measured it is exactly like planned, 49.2mm! How great this is! Now I have all the stuff to get my fatbike in one piece!

    Miranda cranks 04 measure.jpg
     
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  6.  
    Deere John

    Deere John Pedelecer

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    Alright!! Today I mounted the new crank arms, the Q-factor is now reduced with over 2cm. Great!

    P1010085.jpg P1010086.jpg
     
  7.  
    John Fitzgerald

    John Fitzgerald Just Joined

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    Hi Sambal,

    Would you please share the details of this order? I visited this website, and saw no Q-factor selection in the checkout process. You had to specifically request these wider cranks in an email to the seller?

    Thanks!

    -Fitz
     
  8.  
    Deere John

    Deere John Pedelecer

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    yes, irritating isn't it. I had to write the selection as order comment (or something like that). And just hope they read that, but they did!
     
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    John Fitzgerald

    John Fitzgerald Just Joined

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    Thanks for the quick reply!

    So you requested the 55Q:29.6?

    I'm frustratedly navigating their beautiful, though highly unintuitive website now on an iPad.
     
  10.  
    Deere John

    Deere John Pedelecer

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    I don't remember it now but according to my post above it seems like that yes. The one with 29,6mm measured on outer side is the one I got, but I measure the inner side, and got 49,2mm. Exactly like their drawing. So it must be that one then.
     
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    anotherkiwi

    anotherkiwi Pedelecer

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    The web site does suck badly in a beautiful kind of way...

    I remember SW pointing me to these cranks but then I found the Shimano steps ones at 20€ for bafang et al. Now I am hunting for 160 mm or 165 mm cranks so I may have to swallow hard and cough up 60+ € :eek:
     
  12.  
    Sherman

    Sherman Pedelecer

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    Good find guys! There might be something about eFatbike cranks. I've gone thru couple cranks arms (got them warranteed) and I know one guy who mangled his crank arms in no time after getting new Fat ebike.

    Maybe it's the rocky terrain, or combination of monster traction and push of the motor. I've been a bit hesitant to ride rocky trails because of the cranks. KTM left side crank has a very wide curve and it's good to know there are 3rd party parts available if I fail to source original KTM parts.
     
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    anotherkiwi

    anotherkiwi Pedelecer

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    Or the ridiculous Q factor?
     
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    Deere John

    Deere John Pedelecer

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    My original cranks broke because I had a crappy crank remover tool that broke the threads! Very frustrating, after that I bought a quality tool.
    Actually I used it yesterday again when installing the light cable. They sit very tight on the crank arm and I have to use spacer for the tool to reach. But it works good.

    @anotherkiwi : don't think the Q factor affects this. I think it is something like Sherman is on to but specifically the fact that a fatbike makes everything so easy so you ride harder than you're used to do and that stresses everything more.
    My fatbike has rolled 2800 km now without problems (except the really crappy hubs, see other thread). So I must say I am quite amazed how great it actually has worked. But... just because I say this the motor might fall off next ride :)
     
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    d8veh

    d8veh Pedelecer

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    That's the problem with the Bosch system. You only get the Q factor. I've got X-factor in mine. It's much better.
     
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  16.  
    cycling weakly

    cycling weakly Finding my (electric) wheels

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    I take it you bought the Steps cranks to reduce the Q factor on the GSM I know the one I had was very wide. Do you know what the Q factor is with the Steps cranks. My BBS02 with standard cranks is 179 mm. I see you are looking for short cranks. Spa Cycles at Harrogate may be worth checking out.

    Steve
     
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    anotherkiwi

    anotherkiwi Pedelecer

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    I posted it in my thread gained 24.6 mm IIRC. I bought the STEPS ones because I am a horrible fashion snob and the ones supplied were ugly beyond measure. The Q factor improvement was an additional extra :D

    On the trike I want to go down to 165 mm cranks maybe even 160 mm.
     

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