Viewing 13 posts - 1 through 13 (of 13 total)
  • Clueless 2×11 question
  • trashbat
    Free Member

    Hello. I used to know things about bikes, but most of my knowledge has evaporated or rendered obsolete by the advancement of human civilisation.

    I’ve got a Cotic Soul, on 27.5″, with a 2×11 XT setup that I picked over 1×11 because I wanted a do-everything bike. I ride on road a fair bit normally. At the moment, given the situation, it’s looking like if I get out it’ll be all road.

    I’ve got 38/28 up front, and it seems to have been a sensible compromise for everything but road, but I spin out just shy of 30mph, and I miss being able to go a bit quicker.

    I have in my head that the biggest chainring my XT front mech can take is 38T. Am I right? What would I need to achieve what I want? Is it worth bothering?

    JonEdwards
    Free Member

    No idea about front mech capacity on mtbs these days, as it must be best part of 10 years since I bought one, but what cassette do you have? If you have a Shimano one or a lower end SRAM, with an 11T top sprocket, you could swap to an XD driver based SRAM cassette which will give you a 10T top, so about 10% taller. Obviously you’ll need the new free hub body too.

    qwerty
    Free Member

    That’ll depend on the “capacity” of your front mech – it’s ability to cope with the range between 28/38. If your after road only you could put any size single / narrow wide chainring on if your not fussed about using the 28, and ditch the front mech.

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    hols2
    Free Member

    I spin out just shy of 30mph

    Put some big heavy DH tyres on. You won’t spin out on road any more.

    trashbat
    Free Member

    but what cassette do you have?

    Shimano 11-42. Hadn’t clocked there was a 10T option, so I may look at that, cheers.

    If your after road only you could put any size single / narrow wide chainring on if your not fussed about using the 28, and ditch the front mech

    True, I guess that’s more of a commitment, but then who knows how long this’ll be useful for.

    Put some big heavy DH tyres on. You won’t spin out on road any more.

    Heh, yeah. We’ve still got hills though.

    breadcrumb
    Full Member

    There’s only a 10t option for SRAM XD driver freehubs.

    If you go 1*11 In find on my gravel bike a 42t chainring coupled with a 40/11 cassette gives me a good range for road use. I think when it needs replacing I’d look at a 44 or 46 chainring and a 42/11 cassette.

    tjaard
    Full Member

    Swapping cassettes is very expensive: you’d need the xD freehub body, and an xD cassette, not sure in £, but here is the US, that’s usually about $100+$150.
    Chainrings would be cheaper, but you’d need to go to 42t to get the same 10% increase. I bet you front derailleur would be fine with that, since there have been mtb cranksets sold with that. Make sure to up the small ring as well to be keep total chain capacity the same for the rear derailleur.
    And check that you can move your front derailleur up far enough to clear the taller chainring.

    Personally, I don’t think it’s worth the hassle changing the front.
    The rear is easier and guaranteed to work. It also drops a lot of weight, since the cassette is a lot lighter. If it was full suspicion, I’d go for it for sure, to save unsprung mass, but on a hardtail. Not sure it’s worth it.

    joebristol
    Full Member

    I’d just go to Planet X and grab the cheapest Carbon road bike they’re punting out at the moment and not compromise my mountain bike.

    n0b0dy0ftheg0at
    Free Member

    Personally, even though I have a 34/50 compact and 11-32 on my road bike, I won’t be looking to break 30mph very often while the lockdown is on and risking a 999 callout as and when I might regain conciousness after a wipeout. There’s very few descents between Owlesbury and Butser Hill that I’m happy to “kamikaze” on, because even though the traffic levels are usually very low up there, there’s often large branches or even whole trees blown onto the road plus suicidal pheasants crossing the lanes. The crosswinds up there can sometimes be phenominal up on the ridge by the Sustainability Centre or heading down North Lane after climbing Harvesting Lane.

    trashbat
    Free Member

    n0b0dy0ftheg0at, I used to live down there (Bishops Waltham for a few years) and I remember Butser Hill fondly – mostly because whatever speed I allowed myself to get to, that was the speed I had to go at from then on, or more, no real hope of slowing it down again. Sometimes there was a circus at the bottom and I had visions of becoming part of the show.

    I see your point and I agree but this is much more boring than anything around the SDW. I’m talking long, low risk road descents where on my old long-ago-stolen 3×9 bike I could contribute meaningful effort for much longer than on this. It’s hard to quantify the difference and maybe I should just live with it but it feels like something’s missing.

    bsims
    Free Member

    My SLX 670 front mech had 40:28t chainrings. That was on a BFe 275 origionaly so I would guess similar age.

    They are an XT 780 chainset

    n0b0dy0ftheg0at
    Free Member

    I’m glad to took my leftfield reply as not a personal attack on you, we all need to mak our own judgements of what to do in this current pandemic, since discovering the hills up there three years ago I’ve noticed on the rare time I’ve been out with others that I’m usually by far the most nervous descender… My RTC just over six years ago and its physcial consequences left me very nervous about using a road bike for some time.

    If you’re only looking for a bit more speed on the road, maybe look at things such as…
    Narrower bars and lowering their height above the headtube
    A longer stem (I swapped out the 80mm +/-6 degree for 110mm -8/-16 on my commuting fatbike)
    Some nice 27.5″ slicks that don’t bulge out beyond the external rim width of the wheels, for example https://www.merlincycles.com/schwalbe-one-v-guard-evolution-road-folding-tyre-650c-188439.html (although at 25mm, you would probably want an internal rim width no more than 19mm)
    “Racy” fit clothing, for example https://www.planetx.co.uk/i/q/CLPX365MGMCNJ/planet-x-365-magma-convertible-jacket with two other bits in the “3 for 2” is a steal, love mine!

    trashbat
    Free Member

    Oh, no worries there. We should definitely be thinking carefully about exposure to risk, both literal and how things are perceived by others. I’m overly risk-averse with physical stuff at the best of times anyway, it limits what I do with my bike. In happier times I’d be looking for some SDW-style rolling trails but although we have some local routes, it would be difficult in parts to avoid close contact, so I’ve kind of concluded that road is the answer.

    Some good things to think about in that post and throughout the thread. I’ve got some WTB Horizon slicks but they’re 47mm. Currently it’s still on offroad tyres because I haven’t been bothered to swap them out recently. I’m not necessarily looking for overall speed or efficiency, just to get a bit more oomph in places and subsequently safely carry a bit more momentum. I remember trialling the Soul on 1×11 from the warehouse at Calder, with my dad on his road bike, and I was completely out of the picture on the road descents, even though he wasn’t remotely pushing it. My 2×11 setup has made that kind of scenario much more well-rounded but still not quite what I want. When offroad it’s predictably great.

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