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  • Like a Fargo, but carbon, design a bike for me 2!
  • oliverracing
    Full Member

    a few of you may remember my design my bike for me thread last year, along with the build thread, where I designed and built a carbon full suss xc bike, which has been a great success (even it it has had a few minor breakages).

    I’m now looking at building a 29er bikepacking monstercross rig, suitable for carrying kit for 5 days+, I’m pretty open in terms of geometry but I keep coming back to a salsa Fargo, so was wondering if anyone has any ideas of bikes I should be looking at for inspiration!

    So far I’ve derermind that it’s likely to be run with a rigid fork/semi fat front tyre but I don’t want to rule out some suspension so will have to be suspension corrected, I like the idea of being able to runs semi fat rear tyre too, but I also hope to do some alpine trips on this so will want to be able to run triple chainring, which will add to the challenge of packaging the front mech/bb area.

    so… anyone got any tips or builds that they have attempted similar to this? and how did they work out?

    scotroutes
    Full Member

    If by semi-fat you mean 29×3″ (knard territory) then a triple will work just fine.

    I’d also consider 650B+ as a good wheel/tyre option, retaining the BB height and shorter chainstays of your 29er.

    oliverracing
    Full Member

    yeah I ment to say 650b+ as I had seen that the rocky mountain Sherpa prototype was basically an element with slightly widened stays – so would likely have two wheelsets. Doing some quick drawings the stay width required for 3 inch tyres will start to get pretty close to the chainrings!

    STATO
    Free Member

    Loved my Fargo, so good choice as a sterter for goe, but I changed to a spearfish as the suspension allowed you to ride fun trails and little bit easier.

    If you want rigid, the new Jones 29+ might be a good concept to follow, or that ‘Slack29er’ thread on here (forgot the name of the bike now).

    thomthumb
    Free Member

    If by semi-fat you mean 29×3″ (knard territory) then a triple will work just fine.

    I’m not sure this is 100% correct. surly have made the OD chainset to suit the krampus it moves the granny to the middle position.

    I have wondered whether you can use a square taper chainset and a v. long axle….. (idle wonderings for now)

    have you seen salsa prototype

    some one on mtbr has built a 29+ fargo-alike

    Rik
    Free Member

    That 29er+ fargo-alike is awesome. Would love one of those as my touring bike!

    scotroutes
    Full Member

    Aye – mibbe the 650×2.75 WTB tyres would be a better option.

    oliverracing
    Full Member

    To be honest the semi-fat tyre on the rear were just an idea, and the bike will be used with a 2.0-2.2 on the back and a 2.2-2.5 on the front most (if not all) of the time, I was really jut seeing if it would be an easy compromise should I get the urge to convert it to a semi-fat bike.

    I suppose if chain/tyre clearance is the issue I could always just run a single ring when I decide to put some 650b+ tyres on it (those WTB tyres look a very nice option, but can’t seem to find any specs/prices/availability on them).

    As for the 29+, that really does look like it will steamroller over anything, almost as much as maximusmountain’s 36er!

    I’ve heard from some people that Fargos handle weird/badly with weight on the forks and bars (eg anything cages with 2kg per side, and 3kg in a bar bag), although this was a Mk1 being talked about, so I presume this has been sorted in the later models?

    jameso
    Full Member

    Fargos handle weird/badly with weight on the forks and bars (eg anything cages with 2kg per side, and 3kg in a bar bag

    7kg?! Pretty much any bike that rides well unloaded will handle badly (imo) with that much weight on the front unless it’s a dedicated touring bike or short trail design and an unloaded short trail bike has traits that many won’t like without the load stabilising the front end. It’s safe to say that if you want a bike to carry a load up front you need to factor that into the geometry, ie some bikes make better bikepackers than others. Also that mixing different wheel sizes is a tricky thing to balance, it can work ok within a narrow range or a wider range if you’re happy with a more ‘jack of all’ sort of bike.

    oliverracing
    Full Member

    Yeah- I’ve just redone the maths on what I’ll likely be sticking on the front and it will be more like 4.5kg so a bit more reasonable and about what I have had on the front of a 100mm full suss without too much of an issue. I’m happy to forget ability to run front suspension to help a bit with raising the front loading ability, but in that case I would definitely want to be able to run a 29×3.0 tyre!

    I’m fully aware that “jack of all” bikes can be tricky, if not impossible to get right when trying to be too ambitious, which is why I’m making sure I have everything sorted before I start the build. I was under the impression that 650b+ and a 2.0 29er tyre diameters were within 5mm of each other, is this not the case?

    jameso
    Full Member

    You’ve probably worked through more hands-on stuff than I have so hope that didn’t come across as an egg-sucking comment!

    650b+ and a 2.0 29er tyre diameters were within 5mm of each other

    ODs are about 725-740 for 650+ and 735-750 for 29″ so there’s certainly some overlap.
    eg a 2.35-ish 29er tyre vs the WTB 2.8 650+ which isn’t really that big
    [url=https://flic.kr/p/oH3b6c]Eurobike odds and ends[/url] by james*o, on Flickr

    everyone
    Free Member

    (even it it has had a few minor breakages)

    Some minor

    breakages.

    (Sorry* Oli, it had to be done)

    *not sorry

    oliverracing
    Full Member

    Jameso – I’d much prefer to have my ideas criticized than to spend 3 weeks building it to find it doesn’t work! Good to see that although there’s a differences, it’s not huge (especially compared to 2.0 to 2.4 tyres which I’ll happily change between) – so if I look at designing it around a 2.1-2.1 29er tyres then it should be fine with 650b+.

    Nathan – thanks for that, although both were technically crash damage! (the second one was a tube vs rock moment) I’ll admit the full suss was probably pushing the limits of homebuild technology, but the hardtail is still going strong 1 1/2 years on!

    oliverracing
    Full Member

    So, got a little bored over the weekend and started putting some CAD together to work out how realistic this really is, looks like getting a 27.5×3 inch tyre in should be reasonably easy, as should the ability to run a triple (just). I’ve ended up with 160mm head tube, which is only 10mm more than the fargo. I’ve also designed it around 470mm Niner forks.

    For reference the grey tyre is the 650b+ and the black is the 29×2.35.

    Looking at this it looks like Toe overlap could be an issue, has anyone found this to be the case on a Fargo? (175mm cranks on Large frame?)

    treeman
    Free Member

    Really interested in this project as was looking at getting a Fargo but was put of by the weight at over 4kg for frame and fork! Do you plan on putting these into production? Also why do you have such a big gap around the top of the tyre on the seatstay junction?

    oliverracing
    Full Member

    I’m not really setting a target weight, although I guess it will end up sub 2.1kg for frame and fork as the previous hardtail frame I made weighs about 1.5kg plus a 600g fork. I’me also going to be using vacuum bagging for this frame will should hopefully drop some weight/add some strength.

    As for making them for other people I think the cost would be a bit prohibitive due to the amount of time it takes to make a frame, I wont rule it out though but it would be with a very limited warranty. It also wont likely be until summer 2015. If you really are interested send me an email (in my profile)

    The gap around the top of the tyre was just a relic from seeing how a 29×3.0 tyre would fit and would realistically be a lot smaller.

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