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TT bike frame

gloomyandygloomyandy Posts: 520
edited September 2014 in Road buying advice
I've ridden a few TTs this year and plan to do more next. Using my road bike for these has become a bit of a pain (adding clip on bars, swapping cassettes etc.), so I've been thinking of a winter project to build up a bike from a frame (I have a selection of bits I can use so really only need a frame and bars). I've been looking at the planet-x exocet 2 frame and have been able to try a small frame that belongs to a club mate. I reckon with this size I need a number of spacers (approx 20mm) and a 100mm stem to get a reasonable position. But looking at the size charts I think I could pretty much get an identical position on a medium frame with less spacers and an 80mm stem. So a couple of questions. One am I right about the frame sizing, is there a downside to using the bigger frame? Two what other frames are there that I should be thinking about?




  • GrillGrill Posts: 5,610
    Smaller frame will be slightly more aero. If you're trying to carry over geometry from your road bike w/ clip-ons to a TT frame, you're doing it wrong. You have a much steeper seat tube angle and you'll be riding quite a bit more forward than on the road bike.

    Best bet is to go with an adjustable stem and highly adjustable bars to dial in your position. Sizing-wise, if you normally ride a small road bike frame then you'll do the same for a TT bike.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • Hi,
    I'm basing the fit on trying the small frame on a club mates bike, not on my road frame. Looking at the geometry of the planet X frame there seems to be only a very small difference between the small and medium frames. Given that I think I will need a reasonable amount of spacers to get comfy on the small frame I was considering the medium, but I'd appreciate any thoughts on how close the two frames really are in size. Planet-x seem to have a good deal on these at the moment, but don't have many of the small size in stock, so I would get a wider choice of colour with the medium frame, but obviously don't want to compromise the fit on that basis.

    Any suggestions on a set of not too expensive but adjustable bars to go with? Same for the stem? I'm not decided on the planet-x so would happily take a look at any other alternatives for around £500 or less.
  • GrillGrill Posts: 5,610
    Ian Cammish's PDQ bars offer the best bang for your buck, and since you can run spacers under the pads it won't have an adverse aero effect.!pdqbarsshop/c1r5m

    It's difficult to say which frame size would be best, but the PX geo does seem to be a bit smaller than some others. Nowt wrong with running a 100mm stem. Ran 110 on my old TT bike.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • Thanks Grill for the bar recommendation they look interesting.

    Do you have any thoughts on the px bikes and how much they differ in size, it looks to me like they are not very different, but I may have missed something! They seem to have the same angles and the head tube is slightly taller (8mm) and the top tube is slightly longer (15mm), this does not seem a very big difference and a change in stem length and spacers, could be used to adjust for the difference, but perhaps I'm missing something obvious!

    Thanks again
  • GrillGrill Posts: 5,610
    Not much difference in sizes. The seat tube angle is a bit steeper and the top tube is a bit shorter than most, but that shouldn't be too big a deal. Like I said earlier, if you go for the PDQ's then there is no need to run spacers under the stem as you'd run them under the armrests instead.
    English Cycles V3 | Cervelo P5 | Cervelo T4 | Trek Domane Koppenberg
  • I am thinking about a similar project but not sure which frame to go with, Exocet 2 or maybe canyon speedmax AL.

    Any reason or preference of one over the other?
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