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Lockdown TT build

Discussion in 'Pedal Powered' started by GSVBagpuss, Mar 30, 2020.

  1. GSVBagpuss

    Mobster

    Joined: Jun 11, 2013

    Posts: 2,547

    I’m thinking of filling my weeks inside with an n+1 project. Never ridden a TT bike but why not?!

    I think it can be done cheaply with second hand parts if you’re not too fussy about latest and greatest tech. Anyone got any tips or suggestions? I’m thinking 10 speed 105 from a few years ago would be fine. Would my measly 250w manage to turn a 53/39?
     
  2. Jonny ///M

    Capodecina

    Joined: Nov 23, 2004

    Posts: 10,011

    Shifters and wheel dictate the speed.

    10 speed parts can be as expensive or more expensive than 11 speed parts.

    53-39 will be fine, just ride up the block a little for a gear that works.

    Gives you the chance to get ontop of it when you have a tailwind too.
     
  3. SoliD

    Capodecina

    Joined: Feb 25, 2004

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    Location: Portsmouth

    As Jonny said, you're probably better served with 11sp, if you need any parts go to time trialling forums, good active for sale section.
     
  4. mrthingyx

    Man of Honour

    Joined: Apr 3, 2003

    Posts: 15,447

    Location: Cambridge

    I have found that most of the *magic stuff* associated with TT frames is down to marginal gains...

    For me, the key things were seat, frame size (I found a smaller frame more comfortable) and aero bar position: posh wheels are great, but my legs need to be better.

    As you'll be using bar end shifters (presumably) the drive train will be driven by cost: I have found on my routes I *might* use four gears (normally three) and so what my legs are pushing is slightly academic.

    If you're going new, go for cheap and sink the money into your position. ;)

    CAVEAT: I am a very long way from even being below average, so bear that in mind!
     
  5. Berger

    Capodecina

    Joined: May 22, 2003

    Posts: 10,300

    Location: Wigan

    I found last year an 11-23 cassette to be a “marginal” gain, I could keep my legs in my optimum cadence, eliminate that missing 16/18T I think on the 11-28T cassette which could result in quite a jump in the middle of the block.

    I think mine was a cheap(er) Ultegra 6800 as they were being discontinued.

    Looks like going Shimano anyway, but the Sram TT shifters are very expensive, even the not return to centre ones.

    That kind of wattage and gearing will be great, you’ll be in the middle of the block which is best from a drivetrain efficiency point of view and small increments in gearing.

    Towards the smaller gearing on the cassette at higher power/speed you’d be looking at larger chainrings and other stuff which will cost more money.
     
  6. mrthingyx

    Man of Honour

    Joined: Apr 3, 2003

    Posts: 15,447

    Location: Cambridge

    Never understood this... The R2c ones are actually almost as expensive as a whole group set!
     
  7. GSVBagpuss

    Mobster

    Joined: Jun 11, 2013

    Posts: 2,547

    Thanks all for the comments!

    Because they are getting rarer? I run 10 speed 105 on my (clearly quite old) road bike and was thinking of doing the same for the TT as it’s been very reliable and I can buy second hand parts to reduce cost and reuse wheels to start with etc. I need to do a mapping of what can be second hand and what I want to be new - crankset new but shifters and brakes can be second hand for example. I’ve found a 105 53/39 crankset for £52 which seems like a bargain

    I also want to try making my own disc wheel cover for £30 like GTN did!
     
  8. Jonny ///M

    Capodecina

    Joined: Nov 23, 2004

    Posts: 10,011

    Just how it seems to work, they sell less of them so can make more money per item vs selling loads of 11 speed parts for less margin.

    If you go 11 speed at the rear you can run a 10 speed chainset fine and if you stick a 10 speed wheel in you only really need to screw the low
    limit screw in a bit. Maybe a slight adjustment of the barrel adjuster.


    Looks like the bar end shifters are about the same price second hand, certainly not enough to make it worth it.

    https://www.chainreactioncycles.com...hVhF4SyrAiy1InsCE4EgY_5V2snrhpCxoCoLYQAvD_BwE

    10/11 speed rear dérailleurs are basically the same price so one of these.

    https://www.chainreactioncycles.com...hVhF4SyrAiy1InsCE4EgY_5V2snrhpCxoCoLYQAvD_BwE

    Don't know if you need a braze on or band on front derailleur.
     
    Last edited: Apr 1, 2020
  9. SoliD

    Capodecina

    Joined: Feb 25, 2004

    Posts: 14,691

    Location: Portsmouth

    Go single front chainring for the next marginal gain.
     
  10. Trig

    Mobster

    Joined: Oct 18, 2002

    Posts: 3,834

    Location: Leicestershire

    Whatever you do, just don't post pix's, nobody needs to see your legs in lycra bud ;)
     
  11. GSVBagpuss

    Mobster

    Joined: Jun 11, 2013

    Posts: 2,547

    I was thinking that more down to laziness of not needing to install a front mech and cable :)
     
  12. GSVBagpuss

    Mobster

    Joined: Jun 11, 2013

    Posts: 2,547

    Just so I understand, I can run a 10 speed crankset but would need an 11 speed front mech and shifter because the 11 speed chain would need the larger front mech movement?
     
  13. Berger

    Capodecina

    Joined: May 22, 2003

    Posts: 10,300

    Location: Wigan

    10 speed crankset and rings yes no problem.

    Shifter and FD you might be fine with using 10 speed as it’s just a friction shifter rather than an indexed shifter.

    The 11 speed cage might be a slightly different design, with 10 speed you can sometimes need to trim at the limit, ie big/big.

    If you have them lying around then I’d try it, if buying new Id just buy the 11 speed.
     
  14. GSVBagpuss

    Mobster

    Joined: Jun 11, 2013

    Posts: 2,547

    Awesome, thanks
     
  15. GSVBagpuss

    Mobster

    Joined: Jun 11, 2013

    Posts: 2,547

    An update for those who care. Got myself a second hand but barely used 2015 Ribble TT frame with a new 10spd crankset and 11spd rear mech. Just need the other bits now! I’ve worked out that I won’t need brakes for a few months so can buy those later
     
  16. mrthingyx

    Man of Honour

    Joined: Apr 3, 2003

    Posts: 15,447

    Location: Cambridge

    Nice!
     
  17. GSVBagpuss

    Mobster

    Joined: Jun 11, 2013

    Posts: 2,547

    Next major decision is to push the boat out a bit with really nice bars or keep it cheap and cheerful. I need the frame to arrive and see how it fits first I guess. 3T Aduro are going cheap but don’t think it will match very well!
     
    Last edited: Apr 4, 2020