Advertise on Bikeforums.net



User Tag List

Results 1 to 9 of 9
  1. #1
    Senior Member surreal's Avatar
    Join Date
    Mar 2002
    Location
    NJ
    Posts
    3,024
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)

    SA IGH off-road?

    So, i just saw sixty-fivers 3speed hardtail on a different thread, which got me to thinking:


    How does the 3 speed do off-road? I've been thinking about trying such a thing with an x-rd3, if i can get some indication that it can run a 2:1 ratio, offroad, without it getting fried. Obviously, no shifting under load, but i was thinking of using it like a singlespeed, with options. IE, coast, shift to low before a climb, start pedaling. Crest the hill, take a breather for a second, shift into high, cruise down.

    Any thoughts?

    -rob

  2. #2
    Senior Member
    Join Date
    Oct 2009
    Location
    England, currently dividing my time between university in Guildford and home just outside Reading
    My Bikes
    Too many to list here!
    Posts
    1,861
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    I think the new SA 3-speeds could probably take it, although you'd be better off with the rotary gear selector than with the indicator chain, because a) I think it uses a solid axle, which is presumeably stronger and b) the selector is inboard of the chainstay, so it would be less likely to get broken in a crash. The other issue might be the drum brake, you might want the XL-RD3 (90 mm drum rather than 70) as it's more powerful. There is now an SA three-speed with disc brake mounts on the shell though, you might try that instead.

  3. #3
    Real Men Ride Ordinaries fuzz2050's Avatar
    Join Date
    Sep 2008
    Posts
    3,637
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I'm pretty sure SA advises against it; not to say it can't be done though.

  4. #4
    tcs
    tcs is offline
    Palmer tcs's Avatar
    Join Date
    Mar 2007
    Location
    Parts unknown
    Posts
    4,157
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The Sturmey guy on Facebook said they don't recomend any of their hubs for off-road.
    "When man first set woman on two wheels with a pair of pedals, did he know, I wonder, that he had rent the veil of the harem in twain? A woman on a bicycle has all the world before her where to choose; she can go where she will, no man hindering." The Typewriter Girl, 1899.

    "Every so often a bird gets up and flies some place it's drawn to. I don't suppose it could tell you why, but it does it anyway." Ian Hibell, 1934-2008

  5. #5
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    514
    Mentioned
    31 Post(s)
    Tagged
    0 Thread(s)
    Just riding un paved paths, seems not a huge stress, gravel roads , etc. but yea one end of the axle
    drive side, is hollow.
    bombing down a hill with drops and 'air' under you wheels, might break axles.


    Rohloff axle gets a lot thicker in the center as It accommodates gear shifting controls and such

    What kind of external ratios ... for chainring and cog may matter..

  6. #6
    Senior member Dan Burkhart's Avatar
    Join Date
    Oct 2004
    Location
    Oakville Ontario
    Posts
    4,908
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fietsbob View Post
    Just riding un paved paths, seems not a huge stress, gravel roads , etc. but yea one end of the axle
    drive side, is hollow.
    bombing down a hill with drops and 'air' under you wheels, might break axles.


    Rohloff axle gets a lot thicker in the center as It accommodates gear shifting controls and such

    What kind of external ratios ... for chainring and cog may matter..
    Another feature of the Rohloff that helps off road durability is the fact it does not have a through axle. The non drive side axle plate provides a bolt on stub, meaning the axle ends inside the hub.This means the axle itself is pretty much impervious to bending. One thing that will cause a gearhub to cease functioning is a bent axle. For this reason, the earlier suggestion of using the 3 speed with the rotary gear changer is a good one, as it has a solid axle.
    Gearhubs demystified and other cool stuff.


    Rule #12: The correct number of bikes to own is n+1

  7. #7
    Senior Member surreal's Avatar
    Join Date
    Mar 2002
    Location
    NJ
    Posts
    3,024
    Mentioned
    9 Post(s)
    Tagged
    0 Thread(s)
    rohloffs are awesome. for over a grand, they oughta be.

    xrd-3 hubs cost, like, $80, so they fit my budget better. I like everyone's input here. Here are some thoughts that hit me as i read 'em:

    I'm a 250lb kind of guy. I've rode 2 different singlespeeds off-road for awhile, with solid, nutted exles. Very nice. I've also ran *lots* of multispeed hubs offroad, typically on full-rigids or hardtails. all of these hubs have hollow quick-release axles. i've never bent an axle; i just have warped some rims on cheaper wheelsets. Now, i realize that the SA hub has a more-hollowed out axle, and i realize that the SA axle has flats for drop-out placement. This might weaken the axle, but i'm not so concerned about that as i am about the internals. I'm thinking (may be wrong) that the trouble comes in when one does a panic downshift during a climb, and all the torque during the shift fries the planetary gears or whatever. If i think of the shifting as more of a "big deal" switch to a different mode, where i may even stop-to-shift, i don't think i'll fry anything. But, I'm not sure.

    The idea of the rotary-shifted rx-rd3 hubs is a good'n, although they cost about twice as much. I don't crash a lot, so i'm tempted to be stingy.

    I was thinking of rockin' a 36tx18t ratio. This is all highly theoretical, as i've got a few other projects to complete before i start buying anything for this one. And, being as i have no frame yet... and mr.igh says his 8speed alfie runs crazy low gear ratios, and is bulletproof. Still, i like track ends and drum brakes more than track ends and disc breaks or sliding drop-outs. And, i despise EBBs... still, i'm just sort of pondering.

    thanks.
    -rob

  8. #8
    Gear Hub fan
    Join Date
    Nov 2008
    Location
    Reno, NV
    My Bikes
    Civia Hyland Rohloff, Swobo Dixon, Colnago, Univega
    Posts
    2,830
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    A 2 to 1 input ratio used to be the minimum recommended by SA in their documentation prior to the sale to Sunrace. Probably still a good idea for all except the 8 speed hub.

    People of the Op's size/weight used to both break axles and pawls on 3 speed SA hubs per my understanding, even on pavement if they did high torque style riding rather than spinning. In addition to the axle being hollow it has cutouts for sliding parts to reach from the shifting chain to hub parts outside the axle.
    Gear Hubs Owned: Rohloff disc brake, SRAM iM9 disc brake, SRAM P5 freewheel, Sachs Torpedo 3 speed freewheel, NuVinci CVT, Shimano Alfine SG S-501, Sturmey Archer S5-2 Alloy. Other: 83 Colnago Super Record, Univega Via De Oro

    Visit and join the Yahoo Geared Hub Bikes group for support and links.
    http://groups.yahoo.com/group/Geared_hub_bikes/

  9. #9
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    514
    Mentioned
    31 Post(s)
    Tagged
    0 Thread(s)
    Hmmm, low mountain drive range, on my folder, is a 1.44:1 as the 54 is a 21.6t
    with the planetary reduction gear engaged.
    But I'm Old not trying to be a muscle guy. and it is a transportation bike anyhow..

    15t is as big as fits in the frame on my old BrommieT

    at least If I break something in there, I can always get AW3 parts ..
    Last edited by fietsbob; 10-22-10 at 05:10 PM.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •