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Gearing (expensive bikes continued)

At the weekend I noticed people on Tri specific bikes cruising past 2-3mph faster whilst at similar cadence.

Anyone fancy sharing the front/rear cog sizes they run for training/racing? If you run different on your Tri bike compared to your road please make the distinction.

I'm on 50/34, 11-25.

For example I've noticed that the Planet X bikes run a 53/39, 12-25. Possibly the higher gearing seems to account for the perceived expensive bike speed that people are discussing in other threads.

Appreciate a hilly course may warrant lower gearing.



  • FatKnackerFatKnacker Posts: 36
    Until recently I have been running on a 53/39 coupled with either an 11/23 or a 12/27 for hilly courses like Wimbleball.

    During the winter I fitted a compact chainset (50/34 I think) and over the past few weeks have been increasing the length of my rides and I'm now doing 40+ miles in about 2hr 45 and feeling a lot fresher when I get off the bike. I've noticed that my cadence has increased, but that the burn from climbing big hills has decreased significantly. On the downside, I can sometimes spin out at around 40mph on the small cog on a descent. I live in Dorset so there are some decent hills, which I spend considerably more time going up than I do going down so spinning out isn't really that much of a problem.

    I'm doing Wimbleball again this year, so it will be interesting to compare bike times, ans also to compare how my legs feel going into the run after the (relatively) easier cycle...

    Sor far I think the compact chainset was money well spent, but the prrof will lie in the race times.

  • hussler.hussler. Posts: 390
    It makes no odds to what bike you buy/have to what the gearing you have on it.

    You can choose what gearing you like and put it on whatever bike.
    You have a compact, now for me that would be cycling suicide as I am a powerful strong cyclist, but for others it would suit them to have compact on.

    I have 53/39 on both Road (Specialized Tarmac S-Works) and my TT (Argon E114) both of which cost over £3500 each. I have a variety of cassettes, on my Disc wheel I have 11-21, I currently have 11-26 on my training wheel, but I also have 11-25, 11-23 and on my turbo is 12-25.

    I change my gearing to suit what races I will be doing. I can climb 90% of hills comfortably with my 11-23, but its worth having the extra gear ie the 25-11 or 26-11 just incase.
  • gunforhiregunforhire Posts: 457
    Thoughts on putting a compact on a TT bike. Sacrilage?
  • ZacniciZacnici Posts: 1,385

    You may want to look at this similar thread

    If you are an experienced/powerful cyclist then a 'standard' may be your chainring of choice; I have felt much better swapping to a 'compact' but then I don't have thighs of Thor, plus I'm old, fat and knackered.

    As Hussler says with time you start to tweak your gearing; e.g. nice and flat I use a 50/38, hilly 50/34 and contemplating a 52/38 on a 'compact' 110 BCD spider
  • OranjOranj Posts: 45
    Your gearing is plenty big enough. You just need to push the pedals round harder! Even Chris Boardman said:

    "lighter, stiffer & able to use ALL the cassette. Compact would have been my choice for racing, only 4 TDF I'd have added an 11"

    Testers only use 53 or 54 or 55 chainrings and 11 or 12-up cassettes because they have the opportunity to churn really big gears on traffic-assisted, flat, dual carriageways, an enviroment that is alien to your average triathlete.
  • Google for “gear inches calculator”

    It'll give you a way of comparing the sizes of various ratios.

    It's all been said here already, but choose your ratios to suit the course and your own ability.

    Personally, yes I think compact on a TT bike is a waste of time. If you're on a course hilly enough to need a compact chainset, you'll almost certainly be faster on a road bike.

    On a flat or rolling course, select ratios that are as close together as you can manage with. Close ratios make for smaller jumps between the gears. You'll find it easier to select a gear that's comfortable rather than being in too hard a gear, then down shifting to find yourself spinning like mad.
  • largeadelargeade Posts: 166
    Thanks guys, good discussion.

    Ducks flames.. it appears probably I was on the right lines. Whilst I'm at it, I undertand that high cadence is better, and that hilly courses warrant lower gearing, and that TT bikes are best for flatter routes.

    When people without a biking background enter tri I suspect their cadence is naturally low which just doesnt produce high top speed with the standard fit compact chainset that comes on a lot of bikes. Obviously cadence can be improved with training, but the lure of the TT bike kicks in before this can be achieved, they buy the TT and immediately go 3+mph faster.

    Its got to be the aero, position, frame hasnt it? I suspect a lot of people miss the increased gearing in the glare of the bling.

    For flatter courses, and with the power caveat, it appears likely that similar step change could possibly be achieved with bigger gearing on the original road bike.

    I''m not arguing against TT bikes, I'd love one, but I'd like to go 3mph faster without spending all that cash.

    Shoot away ;-)
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