Is the BFe's bottom bracket too high at 140mm+ ?

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  • Is the BFe's bottom bracket too high at 140mm+ ?
  • Too high for what? There’s a current trend towards lower BB heights, slacker angles and bigger wheels. All three factors increase stability at speed – and when you increase stability you inevitably decrease responsiveness. I find the Soul rides extremely well with 140mm Fox 32s, for which the A-C height is 511mm unsagged, and I run them at 15-20% sag (set in the attack position, not seated), so that works out as bit longer than Revelation 140s with more typical 25% sag. That’s about a 15mm BB drop, whilst the Slackline has a 21.5mm BB drop with the same fork length.

    I’m running thin pedals (Vaults) which brings the effective BB height lower but I’m also running very high profile tyres which take it higher. Cotic did say this about geometry but I don’t know what fork lengths were used:

    “Next thing we tried was BB height. With the Rocket development highlighting the pros of a low BB, the first prototypes of what would become the new Soul tubeset came with an EBB so we could drop the BB height 1/2″. The surprising upshot of this was that it made little or no discernable difference to the handling of the bike, despite a lot of testing to make sure this was the case. The only downside was many more jarring pedal strikes, and these are much more troublesome on a hardtail, because there’s no rear suspension to extend and allow you to lever the struck crank ‘up and over’, so you just hit things and stop. ”

    I’ve found the BB of my BFe with 140mm Revelations to feel too high. When I’m riding it, I just feel perched on top and it doesn’t give me that confidence in the corners like on all the other bikes I’ve had or loaned. I’ve had a Lapierre Spicy with some offset shock bushings, loaned a Whyte 146 (low/v.low BB) for a few weeks and am riding an MDE Carve 6, which seems to have a nice mid/low height BB.

    I’m going to lower the forks on the BFe to 130mm this week and I’ll see how it feels.

    Premier Icon johnhe
    Subscriber

    I’ve read posts by quite a few folks who say that the BFe/Soul geometry is fine for forks up to 120mm, but at 140 or 150mm the bottom bracket gets too high. Has anyone anything to add on this topic? Anyone found this to be true? Or untrue?

    Thanks as always for the input.

    They look spot on with long forks. High BB’s are fine, check Josh Bender for proof. A real talent.

    Rob Hilton
    Member

    :mrgreen: That is some colorway scheme blindness

    They handle like crap with long forks

    That wouldn’t look quite so silly with the forks sagged to riding height, the spacers the right side of the stem, and the photo in black & white… But it’s still a very long fork. DT, can you still remember how MTBs ride, since you peaked with laying a table some years back and now ride a roadbike? 😉

    brooess
    Member

    My Soul runs best at c125mm which seems to be the sweet spot for a lot of people. IMO it’s not the BB height, but the head angle and responsiveness that makes 125mm feel right. Steering goes a bit slow when I have the forks at 140mm

    Steering goes a bit slow when I have the forks at 140mm

    A shorter stem sorts that – quick steering when you’re going slow but more stable at speed. I tilted the bars forward a bit on my BMX (equivalent to lengthening the stem) last week and it’s far less nervy now, much less frightening on less than perfect surfaces…

    DT, can you still remember how MTBs ride, since you peaked with laying a table some years back and now ride a roadbike?

    😀

    I’ve peaked already? I was hoping the best was yet to come!

    I’ve peaked already? I was hoping the best was yet to come!

    All downhill from here – on a fireroad…

    😐 Even the last time I rode on a fireroad, I was on a bike with drop handlebars. I think I can only really go upwards from here!

    If you’re dropping your outside foot for major corners, then do longer cranks effectively lower your BB height?

    P.S. David, can I interest you in a nice Rapha cap? It’s only a million pounds and will make you fast like Lance…

    messiah
    Member

    Combo of high bottom bracket and slack seat angle is why I didn’t like the BFe with 160mm Wotan forks. IMHO 140mm is the limit for all round riding but if your purely riding in bike parks and the like where riding back up stuff isn’t a problem then the 160mm was fine as a doonhall only play bike (although for one of those I would still ideally have a lower bottom bracket).

    freeridenick
    Member

    that looks shit and josh bender was hardly a talent…

    _tom_
    Member

    It’s not just the bb that’s too high, it’s the front end that’s too high as well. It just feels awful. Stick with about 120mm max on a ht such as the BFe and it’ll feel good.

    hora
    Member

    Then sharing the angles with a Soul is wrong then?

    A hardcore steel frame with 120mm? It doesn’t make sense.

    Surely the BFE should have a slacker HA/adjusted geo to lower the BB to allow (corrected) for longer forks?

    Otherwise its a jump frame?

    One thing I don’t like on frames is high BB’s.

    kudos100
    Member

    A hardcore steel frame with 120mm? It doesn’t make sense.

    Makes perfect sense to me.

    _tom_
    Member

    Makes perfect sense to me.

    +1. You don’t need long forks for “hardcore” riding, as most slopestyle riders seem to prove.

    xiphon
    Member

    59timesthepain wrote:

    They look spot on with long forks. High BB’s are fine, check Josh Bender for proof. A real talent.

    freeridenick wrote:

    that looks shit and josh bender was hardly a talent…

    Caught hook, line and sinker 😀

    toys19
    Member

    mine has 140mm, but as I’m a fat knacker, with a medium spring it rides likes 105mm.

    Premier Icon bungalistic
    Subscriber

    Bottom bracket height feels just fine to me.

    vikingboy
    Member

    agreed, you dont need >140m to have a hardcore hardtail. Its all about the geometry and suspension taking the edge off the bigger hits not doing the work for you.

    hora
    Member

    What niche does the BFe sit in then? Unless you are into jumps and airtime mainly this wouldn’t suit. Plus if you aren’t doing jumps/airtime- then why not a soul with the same travel?

    If its rocky riding in the Lakes- wouldn’t you be better with a different frame- maybe a short-travel full sus?

    People will ride a Bfe as their do it all bike but then, it’ll be a bike thats a compromise for alot of rides wont it?

    Genuine question but surely in lakes or even Peaks riding- if you are riding fast on a 120mm hardtail you are still getting beaten up whereas on 140 (not much more) – it would help? Maybe better to go with 120/soul and have a more compliant/comfy rear end? (Question marks as genuinely interested as I am looking for a comfy all day hardtail)..

    JonEdwards
    Member

    I have a Soda @ 120mm and a Bfe @140mm.

    They handle differently, but that’s sort of the point. The Soda runs a 70mm stem and narrowish bars and handles in a nippy “traditonal xc” fashion.

    The BFe is slacker, has a shorter stem and wider bars, so is more stable in a straight line, but still can be hauled around fine due to the extra leverage. I can’t say I notice any difference at all in the BB height, but then the riding I do on the BFe (steep, gnadgery, techy, often filthy wet) is of a different style to that I keep the Soda for – long days out in the hills)

    Where the BB height comparison does come into place, is relative to my full sus bikes. Riding slower, techy/trialsy rocky trails, I ground out on the FS and tag pedals and cranks WAY easier than I do on either the BFe or the Soda.

    Practically speaking – 20mm difference axle-crown, = what 5 or 7mm at the BB? Add in more sag on the longer fork, and its going to be maybe 3 or 4 mm difference? You can change more than that using different tyres!

    Premier Icon bungalistic
    Subscriber

    Yes both frames share the same geometry but they do have different audiences in mind to ride them.

    The Soul is more a classic trail bike, it can be built up to a decent weight and it’s probably more suited to the all day ride crowd.

    The Bfe is more directed at those who want something a bit tougher than the Soul, so they can go ‘play’ in the woods, hit jumps, downhill runs etc and know that the frame is tough enough to take the abuse.

    I’m pretty sure Cy and others have covered these differences before, both on here and on the Cotic site itself.

    tymbian
    Member

    So how does the BB height on the Bfe compare to other frames that will take 140mm Forks or even 160 ie. NS Surfe, Alpitude, Dialled Alpine, Production Privée Shan to Name a few?

    Im sure this argument will go on and on, Ive quite often had it with myself inside my own head haha. Ill be honest, i was firmly in the “it rides better with shorter forks” camp, but i just came back from riding the West Highland Way on mine, and as i knew it was going to be gnarly, i put my 160mm Wotans and my Mavic 721s on it. I could have taken my full-suss, but I tried to put together the strongest and most reliable bike I could for the trip. Honestly, i had so much fun, espescially on the first day between Fort william and Kingshouse. I had no idea the bfe could be as brilliant downhill as it is set up with long big-hitting forks, i had always thought that it would be too skittery because the back end is so short. I honestly never noticed the bb height one bit, if anything I felt way more confident on it.

    chives
    Member

    I reckon BB height’s gained in altitude to allow more ground clearance for triple chain rings (rather than fewer pedal strikes). Given the current trend for more compact set-ups (1 x 10 & 2 x 10), that ground clearance issue has largely evaporated. Lowering the BB must make the single biggest (favourable) difference to the C of G on a bike, which would be beneficial in all situations eh? I’d love my Soul to have a lower BB. My Cube shares the same geometry but with a lower BB and material properties aside, feels better.

    With regards to the OP’s question, my two cents would suggest that the change in head angle (rather than BB height)would be more the reason that some folk say 140mm’s ‘too much’. YMMV.

    For me, the change in head angle with my 160 forks on was the reason for my new-found confidence in my bfe`s downhill ability, which more than made up for any difference that raising the bb height made. I took it to Comrie Croft the day after I finished the WHW and I was literally sailing over the technical rocky sections that used to freak me out, it was like it was giving me a whole new skill level because of how slack it was. As several people have already said, it depends entirely what you want to use your bfe for, i reckon the regular discussions surrounding set-ups on Bfes, Souls and Alpines etc show just how versatile these bikes are. They may not partcularly excel in any area, but surely these arguments show that they make for brilliant, cheap to maintain all-rounders. Mine certainly came back from the Highlands unharmed and with a big grin on its face, I wonder if a comparatively delicate full-susser might have given me more problems???

    And another thing, surely the issue here is the length of the fork from the middle of the axle to the bottom of the steerer, rather than the amount of travel it has. Ive just fitted a set of 150mm bombers to my bfe today, and they have almost exactly the same length from axle to steerer as the 130mm forks that came off it. Not all forks with the same travel are the same length, so anybody who wants more travel but is worried about raising their bb height or changing their head angle could look into manufacturers fork dimensions.

    andeh
    Member

    I run my BFe at 140mm pretty much constantly and don’t find the BB to be too high. I’ve never really even though about it tbh. I don’t think I’d want much longer forks though, it would detract from the do-it-all nature.

    It’s never going to feel as low through corners as a full sus as there’s no travel at the back to sink into.

    I do, however, have an On One 1 degree slackset sat on my desk. I may experiment.

    h4muf
    Member


    BFe by h4muf, on Flickr

    hora
    Member

    Lee your chains tooo short!

    Superficial
    Member

    Is it? Big-to-big (a gear you shouldn’t really use) and no chain growth.

    I need a green BFe in my life. 😥

    nick1962
    Member

    Big-to-big (a gear you shouldn’t really use)

    Only on a triple surely?

    Superficial
    Member

    Well, you can use it if you like, but you can get a similar ratio in the small ring and a better chain line. But yeah, it’s not something I worry about. My 1×10 setup is essentially just a middle ring and I obviously have no qualms about using the biggest sprocket at the rear. My point was more that there’s no extra chain growth needed.

    jimthelad
    Member

    All the people complaining about the BFe’s handling with 140+ forks on, clearly aren’t rad enough to get the most out of the frame.

    Stick to mincing about on your fatties.

    Superficial
    Member

    Excellent trolling.

    JonEdwards
    Member

    Well I needed to do some work on both bikes this morning, so being a boring nerd I measured the relative heights. With the same wheels and tyres, there’s 5mm difference – 321mm floor to centre of the BB on the Soda with 120mm forks, 326mm on the BFe with 140s.

    So allowing for a bit of extra fork sag on the longer forks, it really is sweet chuff all (somewhere between 3.5 & 4mm), and a non-event.

    _tom_
    Member

    Do you lot not find that loads of travel up front on a hardtail makes the whole thing feel really unbalanced? As there’s no give at the back so it just sinks forwards loads and feels like crap. Maybe I just can’t set up a fork properly though?

Viewing 40 posts - 1 through 40 (of 46 total)

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