I'm wondering if Trek Emonda ALR have thinner or thicker diameter tubing than the carbon model SL/SLR? I might actually get the aluminum one if it's thinner.

  • If your question is about the tube wall thickness, then that can't be answered for the CF bike because it will vary all over depending on strength requirements.
    – Criggie
    Mar 21, 2018 at 10:05
  • May we ask why you want the bike with thinner tubes? Model selection is usually about components, ride quality, weight and price. Is it just an esthetic consideration? Mar 21, 2018 at 12:30
  • I just like the skinny look of a vintage bike, but not necessarily want a vintage bike. Mar 22, 2018 at 11:50

1 Answer 1


That's a question with multiple answers depending on what you're trying to find out.

From a distance the Aluminium and Carbon bikes look almost identical. Compare these two Emonda bikes and see which you think is CF and which is Aluminium. Try to ignore the wheel rims and different colour schemes, barsm stem, saddle, seatpost, and that both have a carbon fibre fork.

Aluminium bike Carbon Fibre bike S4

SE Bicycles doesn't offer the Spoiler markup tag..... .

The top bike is the aluminium Trek Emonda , and the bottom is the carbon fibre version of the same bike.


  • The CF bike has visually chunkier tubing over the AL one.
  • The CF downtube appears to be consistent thickness whereas the AL one tapers thinner as it drops to the BB
  • That head tube on the CF bike looks enormous compared to the AL head tube.
  • CF bike has thicker chainstays and seat stays over the AL bike
  • The seatpost clamp area looks quite different too - the AL bike has tubes that stop at the welds whereas the CF bike has curves merging one tube around a corner into the next tube.

Curiously, the only tube that looks the same on both frames is the seatpost tube.

However the hidden difference is that the CF bike could be as much as a kilo lighter than the equivalent AL one.

  • 1
    Both are very nice looking bikes, and I'd expect the carbon version to cost more and be specced slightly lower than the aluminium one in terms of drivetrain or other parts. A common dodge is to have the CF bike with 105 grade parts, and cheaper FSA cranks, but the AL bike to have all Ultegra grade parts, which are higher spec.
    – Criggie
    Mar 21, 2018 at 22:41
  • As far as I know Trek always spec full groupset down to the chain. Now I'm debating whether I should take the ALR or SL... Mar 22, 2018 at 11:53
  • @RizkiHadiaturrasyid OK that's unusual, and will be reflected in the price difference. Trying to avoid making this a shopping question, but if you can reasonably afford the lighter bike then go for it. If you ride a lot of hills then the CF bike will help. If you mostly ride flat or have other financial commitments then the AL bike will still be awesomely good.
    – Criggie
    Mar 22, 2018 at 19:01

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