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  1. #1
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    Low Q-factor cranks

    This forum seems to have the line on all the esoteric gear, and I'm hoping to get some leads on low q-factor cranks to mitigate a knee problem. Ultimate lightweight is not a prime concern, but I'm guessing that the lower-q cranks out there are fairly light. Would prefer to stick with aluminum over c.f., and my spending limit is $225. I'm hoping for 160mm or less q-factor.

    I've been away from mtn biking for many years (largely from the knee issue), but I know historically Ritchey has emphasized low q's with their cranks. However, extensive googling has turned up nada for available WCS mountain cranks.

  2. #2
    Trail rider and racer
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    What about getting custom spindles made for your pedals so that you can reduce the Q Factor precisely to what you want.

    Perhaps you could even contact Crank Brothers if you use their pedals and see if they will make a custom set of spindles for you.
    Trev!

  3. #3
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    Quote Originally Posted by Mr. Scary
    Crank Bros offers spindles that are 4mm narrower than stock, but they will not sell pedals with these spindles. You have to buy the spindles separately and they cost $100USD.
    So if you have $400 tied up in Triple Ti's and then add another $100, that is a pricey set of pedals. Of course you could probably sell your longer Ti spindle on Ebay, it will reduce weight for somebody running the Cromo spindle.
    best option for low Q-factor would be very old Ritchey WCS cranks for SQUARE BB. that way you could fit a 103mm road BB. that's the exact setup Thomas Frischknecht used for years.
    Ritchey WCS cranks are ca. 5mm narrower than most cranks out there and the narrower roadie axle helps too. I have a 103mm roadie axle on my Storck powerarms carbon cranks which usually have a little wider Q-factor. this way though my measurement sits at 165mm which is pretty low for MTBs. (same as WCS cranks on octalink BBs).

    in addition, as Mr. Scary already said, have your cleats mounted all the way OUT on your shoes. that way your feet move inward which again makes for a narrower position. usually SPD cleats allow for ca.3mm inward movement. Frischi even modified the cleats to allow for even more side adjustement. there is that tiny stop on the cleats which he simply dremelled away. that is worth another 2-3 mm so all in all he has his feet pretty close together. he even modifoed the backside of his crankarms since they would touch the chainstays when pedaling beeing so close to the frame. he simply shaved them to avoid contact on the frame.

    but as Scary said maybe a shorter pedal axle is the easiest way to get a low Q-factor. especially on Eggbeaters the pedal axles are much too long. i could shorten mine about 8mm on each side without any problem. that alone is worth 16mm on the Q-factor....have a look at your pedals and how far your feet ar away from the crankarms when pedaling! maybe having someone make shorter spindles is the easiest way and cheaper than to buy a new crankset and BB...

  4. #4
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    Some great tips already, thanks. Mr. Scary: which XTR cranks do you use? I was wondering what the q-factor of the older syle is (new ones too $$). Also, does the shorter-than-standard spindle length adversely affect chainline/shifting performance? My understanding is that current front derailleurs have geometry/index points designed for specific chainline measurements. Also, does the short spindle preclude the option of using 3 chainrings? I'm open to the idea of 2x9, btw.

    That's interesting about about the short spindles from Crank Bros. I haven't decided on a pedal system (been using Look on a road bike!), but I was going to select Candy SL's or carbon Atac's. I'm planning to look at them side-by-side to see which will get me closer to the cranks out of the box.

    I saw somewhere on mtbr that Ritchey had a WCS mtn crank with octalink interface, but I couldn't find any on ebay or anywhere else.

  5. #5
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    Ritchey+octalink...

    Quote Originally Posted by pinepig
    Some great tips already, thanks. Mr. Scary: which XTR cranks do you use? I was wondering what the q-factor of the older syle is (new ones too $$). Also, does the shorter-than-standard spindle length adversely affect chainline/shifting performance? My understanding is that current front derailleurs have geometry/index points designed for specific chainline measurements. Also, does the short spindle preclude the option of using 3 chainrings? I'm open to the idea of 2x9, btw.

    That's interesting about about the short spindles from Crank Bros. I haven't decided on a pedal system (been using Look on a road bike!), but I was going to select Candy SL's or carbon Atac's. I'm planning to look at them side-by-side to see which will get me closer to the cranks out of the box.

    I saw somewhere on mtbr that Ritchey had a WCS mtn crank with octalink interface, but I couldn't find any on ebay or anywhere else.
    chainline isn't a problem with shorter spindles. i never had any problems.

    Ritchey does have a WCS crank for octalink BBs (XT spline). that's the exact cranks i use on my winterbike right now...165mm Q-factor.
    they are rather heavy though (ca. 470g for the arms) and you need the heavy 255g XT octalink BB too...not light at all.
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  6. #6
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    Quote Originally Posted by pinepig
    I haven't decided on a pedal system (been using Look on a road bike!), but I was going to select Candy SL's or carbon Atac's. I'm planning to look at them side-by-side to see which will get me closer to the cranks out of the box.
    out of the box, the atac's are closer to the cranks. also, if you arent worried about weight so much, the atacs have a more solid feel when youre clipped in

  7. #7
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    Hmmm. Well, the supply of WCS cranks (octalink and ISIS) seems all dried up anyway. I take it the XTR cranks Mr. Scary is using have a different octalink standard than your Ritchey cranks, nino.

    If I can make everything work well in a low-q setup (with shifting as good as with standard chain lines), with decent durability, then even without the lightest weight I'll be happy.

    This is a new bike build from scratch (Turner Burner en route), so there are no concerns for dx'ing existing components.

    I'm still running square taper on my road bike (Campy), but I was looking forward to trying one of the new interfaces. Mr. Scary's setup appeals to me. If the older XTR M952 cranks will work with the Dura-Ace BB's, we might have something. It looks like the M952's might also use proprietary chain rings? Does anyone know what the q-factor of these cranks on a standard 112.5 spindle (for reference)?

    Edited to add: Forget the 952's, they're too damn heavy.
    Last edited by pinepig; 12-22-2004 at 12:51 AM.

  8. #8
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    Quote Originally Posted by pinepig
    That's interesting about about the short spindles from Crank Bros. I haven't decided on a pedal system (been using Look on a road bike!), but I was going to select Candy SL's or carbon Atac's. I'm planning to look at them side-by-side to see which will get me closer to the cranks out of the box.
    Look roadie pedals are so solid and secure feeling that you should try out some eggies before you buy em. I found my eggies provided too much movement and float and thus you might find it a little uncomfortable.

    Otherwise, all going well, I think the eggies with the short spindle could be a great way to go.
    Trev!

  9. #9
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    I think I'll be happy with the atac's. I tried them (older style) on my brother's bike and they felt fine. If the eggies allow more movement than atac, I'll skip 'em.

    I think my next round of research will involve developing options for using a short-spindle dura-ace bottom bracket with an octalink crankset that meets my criteria for price, weight, and inherent q-factor.

    nino: the dura-ace 7700 BB looks like it is octalink V1, would that work with your Ritchey cranks?

    Mr. Scary: does your frame have a 68mm BB shell? I'm wondering how the DA BB's (for 68mm shell) will work in a 73mm shell. I know putting a 73mm BB in a 68mm shell will work by adding a spacer(s) outboard of the shell, but what about the reverse? Excuse me if I'm missing something very simple and well-known (like I said, been away from mtb's for many years).

  10. #10
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    Da Bb...

    Quote Originally Posted by pinepig
    I think I'll be happy with the atac's. I tried them (older style) on my brother's bike and they felt fine. If the eggies allow more movement than atac, I'll skip 'em.

    I think my next round of research will involve developing options for using a short-spindle dura-ace bottom bracket with an octalink crankset that meets my criteria for price, weight, and inherent q-factor.

    nino: the dura-ace 7700 BB looks like it is octalink V1, would that work with your Ritchey cranks?

    Mr. Scary: does your frame have a 68mm BB shell? I'm wondering how the DA BB's (for 68mm shell) will work in a 73mm shell. I know putting a 73mm BB in a 68mm shell will work by adding a spacer(s) outboard of the shell, but what about the reverse? Excuse me if I'm missing something very simple and well-known (like I said, been away from mtb's for many years).
    only the roadie groups (DA,.Ultegra,105...) share the same octalink pattern as XTR. XT is different and won't fir.

    Specialized once had their Strongarm cranks made for XTR BBs (back in ca. 2000). i had those fitted to a DA octalink BB and it was no problem at all.

  11. #11
    Max
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    watch out when switching to a shorter axle BB. when i replaced my 113mm BB with a 108 mm (didn't change the truvativ stylo team cranks) i couldnt shift to the granny because the front derailleur was already touching the seat tube.

    tune bigfoot cranks have a very low Q factor as well, so usually you'd have to use a 118mm axle or so. maybe using a shorter axle would help you with your Q factor.


    BTW; why is the Q factor THAT important? i mean, do you really notice 5 mm difference when your legs are 800 mm long?


    Skinny guys fight 'til they're burger

  12. #12
    jonny_mac
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    for the older

    xtr cranks you can buy a xt 5-arm spider and then convert it to a compact
    drive. that is the set up i used on my 952 crank arms, and some pros used
    to do it too. you cannot use a DA bb on a 73 shell, it has to be a 68 shell.
    you can have your frame's bb shell faced down to a 68 but it might void
    the warranty if you are worried about that.

  13. #13
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    You can modify your pedals

    I use the new XTR crankset , they have a large Q-factor. So I let somebody make custom tita spindles for my speedplay pedals. They are shorter and lighter than the normal ones

    http://gallery119672.fotopic.net/p9578198.html

    PS : Check my site , they are for sale

    www.janverbeeck.tk
    Last edited by Janman; 12-22-2004 at 08:51 AM.

  14. #14
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    WCS cranks here

    I haven't read the whole thread, but perhaps this is still relevant:

    http://www.performancebike.com/shop/....cfm?SKU=16993

    $80 bucks for the WCS cranks, seems like a good deal if you don't mind ISIS and don't want to spend much $$.

  15. #15
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    I saw those cranks at performance. I'd probably buy a pair if they weren't 170mm.

  16. #16
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    check FRM

    http://www.frmbike.com/comp_mtb/guar...guarniture.htm

    158mm with 108mm ISIS or 163mm in integral design.

    I've been lurking at those for a while...

    Max N.

  17. #17
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    Those cranks are octalink not isis

    Quote Originally Posted by kukusz
    I haven't read the whole thread, but perhaps this is still relevant:

    http://www.performancebike.com/shop/....cfm?SKU=16993

    $80 bucks for the WCS cranks, seems like a good deal if you don't mind ISIS and don't want to spend much $$.
    Just thought you might like to know

  18. #18
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    Max:

    Yes, I saw the FRM's before starting this thread. They are what inspired me (if they can do it, maybe other co's can as well?). The page I saw indicated the ISIS model is 158mm w/ 113mm spindle. $292 at www.notubes.com. Does anyone know more about these?

    On the subjuct of ISIS cranks, does anyone have a Q measurement on the current Truvativ Stylo Team cranks, mounted on a 113mm (for reference) axle?
    Last edited by pinepig; 12-22-2004 at 05:30 PM.

  19. #19
    Max
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    no but i can tel you later, just gotta take them off....


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  20. #20
    PeT
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    Older Ritchey Logic cranks

    Quote Originally Posted by pinepig
    This forum seems to have the line on all the esoteric gear, and I'm hoping to get some leads on low q-factor cranks to mitigate a knee problem. ... I'm hoping for 160mm or less q-factor.

    ... I know historically Ritchey has emphasized low q's with their cranks.
    I just went through this same process looking for a crank for a new bike. I've got the older Ritchey Logic (non-compact) cranks paired with a Phil Wood bb on a Bridgestone MB1 (set up as a single speed) that has a q-factor of 145 mm. On my geared bike I have a not quite as old Ritchey Logic compact crank on a 108 mm Phil Wood Ti bb (square taper of course) that has a q-factor of 155 mm. I have come into possession of a Ritchey WCS crank that when paired with the XT octalink bb has a q-factor of 165 mm. For most mountain bikes, the 145 mm q-factor is too small (the cranks would not clear the chainstays and the chainline is way off). The 155 mm q-factor has about 5 mm of clearance to the chainstays on my Moots YBB, but the chainline is perfect. Note that dura-ace or ultegra dourble cranks have a q-factor of 145 mm. Also, I measured a shimano 105 triple as having a q-factor of 155 mm, with the same chainline as a mountain triple -- could you use a road triple? I personally don't think you have options other than the older Ritchey Logic cranks if you want to get under 160 mm for your q-factor. Like Nino noted above, the mtb pro I respect above all others went to great lengths to keep his q-factor low. While not in his class (!), I find it important for both comfort and efficiency.

    Finally, I have an unused (as new) Ritchey Logic crank with 46/36/24 rings and 177.5 mm arms that when mated with a square tapered bottome bracket (probably 118 mm spindle) would net you a 155 mm q-factor with a modern chain-line and appropriate frame clearance. Let me know if I can help.

  21. #21
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    Quote Originally Posted by Max
    no but i can tel you later, just gotta take them off....
    You probably already realize this, but you only have to take off one side. Reinstall it so both cranks point the same way, and measure as shown in nino's post above. Thanks for checking that!
    Last edited by pinepig; 12-23-2004 at 03:37 PM.

  22. #22
    Max
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    of course i know. my stylo team cranks measure approx. 169 mm, that's with a 68x113 mm BB


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  23. #23
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    PeT: Thanks for the detailed info. Take care of all those old Ritchey cranks, they're like gold!

  24. #24
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    This is a common problem

    I've even encountered it on road bikes, and it seems to occur only with 34,9 mm seattubes, as far as I have experienced.

    Coincidentally, I had RF Turbines on my Rocky Mountain. I've since gone to a Deus crank, but the Turbines (now on my HT) could easily be run with a 108 mm bracket, while shifting properly.

  25. #25
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    Thanks Max!

    Quote Originally Posted by Max
    of course i know. my stylo team cranks measure approx. 169 mm, that's with a 68x113 mm BB

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