Help needed, building a snowbike frame- Mtbr.com
Results 1 to 22 of 22
  1. #1
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    161

    Help needed, building a snowbike frame

    Hi
    I build frames on my spare time. Next frame I plan to build will be one for a snowbike. I know very little about snowbikes and need some help. Tried the framebuilding forum but none of the builders there had any experience with building snowbikes so I thought I might try to find some help here.

    Background
    I live in Stockholm, Sweden. Itís more or less on the same latitude as Anchorage. We get snow but not as much as you since the Gulf Stream make it less cold here, (the winter months are as dark as yours though) The lakes usually freezes during winter. If there is no snow on them we go skating (very nice, some photos here), if there is snow on the ice (happen quite often) you canít skate. One of the reasons I plan to build this frame is to be able to ride on the lakes when the ice is covered with snow . If we are really lucky the archipelago freezes. (Here are some photos from a bike trip a few friends of mine did in Stockholmís archipelago two years ago. Exceptional conditions made it perfect for riding normal mountainbikes.)

    Most of the riding will be done on the same trails I ride in the summertime but now covered with snow. The trails are technical and twisty and I prefer a quick handling bike (I know a snowbike will not be a quick handling bike). The snowbike I plan to build will not be used for multiday expeditions, carrying a lot of equipment. It will be used for epic day rides in the winter, on ice covered lakes or snowy trails. A winter play bike.

    Stockholm is rather flat, there will be no long climbs. I will most likely not be riding in temperatures below -15C

    Material is steel. Canít weld aluminum, donít afford playing with ti

    I do not build or plan to build frames for others. I know it will be much easier just to buy a Pugsley and that if I spent the time working extra instead of building my own frame I could probably afford a Fatback but I find pleasure in building and riding my own frames so please do not try to talk me out of it.


    The questions:

    135, 150 or 165 rear spacing ?
    A symmetric 165mm rear spacing frame looks much better, no question about it. However the limited hubs available (and price tag) has med me leaning to a 17.5mm offset 135mm hub wheel like the Pugsley. Not decided yet thoughÖ
    Any thoughts on rear hub spacing?

    65, 80 or 100mm rims
    - I have seen photos of Pugsleyís with 80mm rims so I assume itís possible to use these rims when building a 17.5mm offset 135 hub wheel but how about the 100mm rim. Is it possible to build a 17.5mm offset 135 hub wheel using a 100mm rim?
    - 65, 80 or 100, which one should I go for?

    Drawings:
    There is something wrong with my drawings. It just does not seem possible to build a frame that accepts the 100mm rims and the clearance between tire and chain seams very small on both the 80mm rim and the Large Marge. (The diameters of the tires in the drawings are: 90mm on the Large Marge, 96mm on the 80mm rim and 108 on the 100mm rim. Chainline is 66mm)
    What have I done wrong ?

    135mm rear spacing, 17.5mm offset




    165mm rear spacing




    165mm rear spacing, only 8 cogs in the rear




    Geometry
    I will start from the geometry I like on 29Ē frames. Is there anything I should change when building a snowbike? I have noticed that the handlebar often is quite high relative the saddle on snowbikes. Should the toptube be shorter or longer than what I usually ride on a 29:er, head angle slacker? I like to keep the chainstays short, is that a bad idea?
    The time I have spent on a snowbike is very limited. Any input on what to think about when it comes to geometry on a snowbike is appreciated. (keep in mind that this is not an expedition bike and that it sometimes will be ridden on technical and twisty trails)

    Thanks !

    Peter

  2. #2
    is buachail foighneach me
    Reputation: sean salach's Avatar
    Join Date
    Sep 2007
    Posts
    6,589
    if you want a quick handling bike, just copy the geometry from quick handling bike you are familiar with. add in a 100mm bb and wider dropout spacing and you're set. i would recommend going wider out back. if the availability of hubs in 165 scares you, go with 150 and an offset bottom bracket spindle to get the driveside cranks a wee bit further out. you might have to lengthen the chainstays a little bit as well, and consequently steepen the head tube angle a bit to quicken the handling.

    the shorter the chainstays, the more likely the chain and possibly front der. with rub the tire. if you went with 1x9 or 1x8 you would have more options. remember that your 100mm bottom bracket is about the same width as the endomorphs. then you've gotta mount chainstays to it, which means; in order to run really short stays (15" would be the shortest, nothing else considered.)you would have to run a low profile machined yoke.

  3. #3
    @adelorenzo
    Reputation: anthony.delorenzo's Avatar
    Join Date
    Aug 2006
    Posts
    1,670
    I posted some thoughts earlier for my opinion on the ideal snowbike design.

    I'm not a big fan of the offset. I don't like building wheels with the offset, and it limits what else you can do with the frame.

    In a perfect world, my snowbike would have non-offset 135 mm spacing front and rear, a narrower BB (83 or even 73 mm), running a Shimano Alfine hub for a single chainline. I'm still not sure if this is even possible, but I think it is.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    4,667
    I think you'd have to offset the Alfine hub. Everyone lists it at a 42mm chainline, and with 80mm rims you'll have a 96mm endo. I'd probably go for a 56mm chainline with an 83mm BB (matches Shimanos crankset offerings) to give sufficient clearance (fairly normal chainline for an SS mountain bike), but I suppose 50mm would be the absolute minimum, but that'd have less than 1mm clearance with the chain. That would require a 14mm offset, about 165mm virtual spacing in the rear.

    Personally, I like 100mm spacing in the front. It allows for a dynamo hub to be used. Unless someone makes a thread on 100 to 135mm adapter to allow their usable on the offset forks... it wouldn't be too hard to machine, but easier to just get a different fork.
    Last edited by Schmucker; 11-24-2008 at 08:42 PM.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Feb 2008
    Posts
    30
    I don't have any suggestions, other than you'll have trouble riding with the cranks set up that way, they're usually opposite each other

    I've never put cranks on like that, at least intentionally

  6. #6
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    940

    New Design

    Here's what I'd like to see.....

    Since you are building a frame, you should design a big BB shell to house a Rohloff or Nexus or whatever internal hub with a square taper, ISIS, or whatever spindle like they do with unicycle hubs. That way most of the weight is centered at the BB, you have single-speed chain line with lots of gears, and you can do a quick-change on the rear wheel when you flat. Rear spacing can be 135.

    I see this as the future of bikes with gears.

    Pat

  7. #7
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    161
    Thanks for your input

    With short chainstays I meant sub 17Ē, maybe 16.75 or 16.5, not trial lenth chainstays

    A symmetrical frame with a 150mm rear hub would be great, but to me it seems like that would rule out any rim larger than Large Marge and the chanline will be messed up. Maybe if I only used 7 cogs in the rear. Or if I did not use a granny up front.
    I guess one does not need the big ring up front. How about the granny ? How important is it ?

    Anthony, With narrower BB, do you mean a chainline less than 66mm ? Seams very difficult to clear the chain from the tire with a chainline less than 60mm.


    150 rear spacing




  8. #8
    No, that's not phonetic
    Reputation: tscheezy's Avatar
    Join Date
    Dec 2003
    Posts
    14,313
    You will want the granny. On the other hand, there have been very few instances where I wished for a big chainring (I run a light bashring on my Pugs instead). A tail wind on a firm sand beach might call for a 44 tooth. Not much else.
    My video techniques can be found in this thread.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    4,667
    Just go with a 165mm. I was thinking that using a 7spd or an 8spd with the 11T or 12T cog removed and a spacer placed behind the cassette. I think it'd be possible to get by with just a 30T on the front (this would require a 94bcd crank). It really depends on how often you use the 22x34. That's about all you lose. It'd work better if you could find a 29T.

  10. #10
    Ologist
    Reputation: Valhalla's Avatar
    Join Date
    Mar 2004
    Posts
    963
    Quote Originally Posted by tscheezy
    You will want the granny. On the other hand, there have been very few instances where I wished for a big chainring (I run a light bashring on my Pugs instead). A tail wind on a firm sand beach might call for a 44 tooth. Not much else.
    Or for lake riding....

  11. #11
    This place needs an enema
    Reputation: mikesee's Avatar
    Join Date
    Aug 2003
    Posts
    13,474
    You can run the 100mm rims with EndoMorph tires in the Pugs frame and fork. Requires grinding/filing off the rim brake tabs (NOT the posts, just the inner tabs) to get the rim to fit through.

    I had to run 8 cogs out back on mine to keep the chain from rubbing the tire in granny/granny.

    MC

  12. #12
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    161
    Except for the looks, why is it so bad with a 17.5mm offset 135 hub ?
    Seems like if itís correctly designed, one could use all kind of rims and even have slightly more chain clearance than on a frame with a 165mm hub.

    Anyone know how what rear hub Wildfire is using ?

  13. #13
    mtbr member
    Reputation: Alhansen's Avatar
    Join Date
    Dec 2007
    Posts
    68

    100's on a Pugs?!

    Quote Originally Posted by mikesee
    You can run the 100mm rims with EndoMorph tires in the Pugs frame and fork. Requires grinding/filing off the rim brake tabs (NOT the posts, just the inner tabs) to get the rim to fit through.I had to run 8 cogs out back on mine to keep the chain from rubbing the tire in granny/granny.

    MC
    Thanks for the info. For some reason I assumed the 100mm's would not fit the Pugs, so resigned myself a future 80 upgrade from the Large Marge's. I rode a Fatback the other day with 80's and I could tell there was a huge difference in climbing traction on steep stuff over what I'm used to with the Marges. Is there, similarly, a perceptable difference between the 80's and 100's, or is it kind of the Law of Diminishing Returns? Also, did you run a 20 granny on your Pugs?

  14. #14
    This place needs an enema
    Reputation: mikesee's Avatar
    Join Date
    Aug 2003
    Posts
    13,474
    Quote Originally Posted by Peter E
    Except for the looks, why is it so bad with a 17.5mm offset 135 hub ?
    There is significant dish with a 135/offset 17.5 wheel. 165 builds totally dishless and with that huge flange width makes for a virtually indestructible ('specially when riding snow) wheel.

    Quote Originally Posted by Peter E
    Seems like if it’s correctly designed, one could use all kind of rims and even have slightly more chain clearance than on a frame with a 165mm hub.
    Incorrect. With the Pugs 135/offset design you must use an offset drilled rim (or drill it offset yourself). 165 allows you to use any on-center drilled rim. Much more selection in on-center drilled rims in every width and diameter.

    Quote Originally Posted by Peter E
    Anyone know how what rear hub Wildfire is using ?
    IIRC, Mark was big on the 135 with offset.

    MC

  15. #15
    This place needs an enema
    Reputation: mikesee's Avatar
    Join Date
    Aug 2003
    Posts
    13,474
    Quote Originally Posted by Alhansen
    For some reason I assumed the 100mm's would not fit the Pugs, so resigned myself a future 80 upgrade from the Large Marge's. I rode a Fatback the other day with 80's and I could tell there was a huge difference in climbing traction on steep stuff over what I'm used to with the Marges. Is there, similarly, a perceptable difference between the 80's and 100's, or is it kind of the Law of Diminishing Returns? Also, did you run a 20 granny on your Pugs?
    The clearance on a Pugs with 100's and Endo's is tight, but not show stopping. I wouldn't let it stop you.

    The 80's hit the all-around sweet spot for width/control/weight for sure. Very noticeable difference in control going from 80 to 100. Yes, I had a 20t on the Pugs.

    MC

  16. #16
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    161
    who makes the cheapest 165mm hub ? Who makes 165 hubs anyway, Hadley, Ringle, anyone else. Are they available with QR or do I need to convert them from 12mm to QR ? Where do I find a 165mm QR ?
    How many holes, 32 or 36 ? Are the 80 and 100mm rims available in both 32 and 36 ?

    I understand that a symmetrical wheel is stronger but how bad is really offset built wheels like the ones on the Pugsley ? Is it a theoretical or real problem ? Have not heard many Pugsley owners complaining.
    Last edited by Peter E; 11-27-2008 at 08:14 AM.

  17. #17
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    161
    Researched 165mm hubs and found these:

    Ringle Lawwill (no longer mad but still available at some webshops) 165/12, 32 and 36 holes, 505g 180 Euro

    Alutech 165/12, 32 holes, 490g, 165 Euro

    DT Swiss 440 165/12, 32 holes, 420g, 300 Euro

    Hadley (canít find any info, do they have a website ?)

    Formula DH/DC 165/12, 32 and 36 holes, 150 Euro


    Can get the Ringle hub at a good price (about 100 Euro) but only in 32 holes. Are the 80mm rims available in 32 holes ? If the rims are available in 32 and you donít insist that I use 36 holes (I weight 170lbs) the Ringle hub seems like a really good deal.

    Donít know the weight of the Hadley but these are all quite heavy hubs.

  18. #18
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    4,667
    Hadley doesn't have a web site. I'm pretty sure DT Swiss stopped making their hub as well. It is no longer on their site.

  19. #19
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    161
    Quote Originally Posted by Schmucker
    I'm pretty sure DT Swiss stopped making their hub as well. It is no longer on their site.
    that's probably true. Found one at sale for 220 Euro. looks like 165 hubs are going to be really hard to find in the future

  20. #20
    no dabs
    Reputation:
    Join Date
    Oct 2008
    Posts
    363
    I've settled on 135mm spacing (cheap, common hubs), offset 17.5mm (form follows function, therefore it is beautiful!) on mine. I'll be re-drilling the left side spoke holes further to the right to get a dishless spoke pattern. The 80 and 100 mm rims I've found (I bought the 100 mm) are only available in 36 hole. Re-drilling 18 holes seems like a time consuming, but completely doable proposition. Drilling 64 of them to run 32 spoke seems more time consuming, but also doable.

    with my drawings, it looks like the chain will just barely not clear the endomorph mounted to a 100mm rim with the extreme granny. that means i can probably run a 3x8 just fine. I'm planning to go 2x7, with a spaced rear der hanger to get all the gear ratio's i normally use in the winter around here. Since i rarely use the very lowest gear, I had also contemplated using a lateral chain guide (read: block of Teflon) to keep the chain off the tire.

    I'm doing a 135 spaced SS disc rear hub for the front hub (cheap, common), and hoping the hub flanges are spaced out enough to work with the horrifyingly wide spaced spoke pattern on the 100mm rim.

  21. #21
    mtbr member
    Reputation:
    Join Date
    Aug 2007
    Posts
    4,667
    Why not make a symmetrical 135mm front fork? Then you'll only have to redrill one rim.

  22. #22
    no dabs
    Reputation:
    Join Date
    Oct 2008
    Posts
    363
    Quote Originally Posted by Schmucker
    Why not make a symmetrical 135mm front fork? Then you'll only have to redrill one rim.
    I thought that was what I said....


    Anyway, yes, that is what I plan to do.

Members who have read this thread: 0

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.