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So I'm planning to get this bike, possibly the later 2017/2018 model:

http://www.polygonbikes.com/id/bikes/description/2016-strattos-s3-black#spec

Which is a well known local brand and practically any bike shop near here should carry one.

Anyway, the bike has more of an endurance geometry, though I wanted a more aggressive one, they don't have one at this price range.

The question is, can I simply swap the stem to drop stem (negative rise) and move the stem down the spacers to get to a 'performance bike' position? or will it still be a different geometry altogether? I can't see much difference in the final position vs an actual performance bike, but I might have missed something.

If it makes a difference, I will be using this bike mainly for 'commuting' to work (I usually ride hard on threshold anyway), some climbing practice, and maybe a few amateur races just for fun.

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  • You may find no benefit to doing so, at least at first, as such a slammed geometry will take some getting used to and training.
    – Chris H
    Commented Jan 30, 2018 at 9:11
  • Currently I'm using a vintage frame with stack and reach ratio of 1.48. This bike Strattos S3 has a ratio of 1.54 which is more relaxed, hence the question. Commented Jan 30, 2018 at 13:23
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    That slightly changes the question to: how can I adjust this bike to better match what I'm used to? which is also a sensible question, even if such a ratio is (IMO) an oversimplifcation of a tricky problem
    – Chris H
    Commented Jan 30, 2018 at 13:51
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    The question stays exactly the same, you just need to lose the knee-jerk reaction to lowering bars.
    – ojs
    Commented Jan 31, 2018 at 1:48
  • As a general advise, it is usually not a good idea to get a bike one does not want and try to change it into a bike that one desires. Often the overall cost to get the right bike from the outset is lower. This is a generalized rule and died not apply to all markets, requirements, or personal situations.
    – gschenk
    Commented Feb 2, 2018 at 20:31

2 Answers 2

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Yes, you can get a more aggressive riding position by dropping the stem down on the steerer tube, and swapping the stem for one with a larger angle (and possibly a different length).

Bikes typically come with 3 5mm spacers, and swapping from a 6 to 12 degree 100mm stem drops an additional 10mm, so you should be able to easily drop the bars by 35mm.

What we cannot tell you is whether you will be able to get the bars low enough for you. I suggest that you use you current bike as a baseline if it is set up the way you like it. Measure its stack and stem rise, then compare that to the bike you are looking at. Also, go get a test ride if that is possible in your location, or at least sit on the bike and get a feel for the rider position.

There are other differences in steering geometry between the bike you are looking at and the higher end ones. The higher end ones have slightly steeper head tube angles and will have slightly quicker steering. Again, you will have to determine if that works for you.

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  • A lower bar position usually also requires a longer stem. When buying a new stem that ought to be considered. If the stem is already long in the higher position, it may be difficult to find such a stem, and the steering geometry might suffer as well.
    – gschenk
    Commented Feb 2, 2018 at 20:26
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The frame geometry of a bike influences riding a lot and cannot easily expressed only by reach and stack.

But you can compare frames directly. It takes only very little effort to enter the frame geometry into a CAD programme. Use the bottom bracket as coordinate centre for each bike and compare the frames.

This allows you to compare the geometry you know from your bike with that of the endurance bike and the performance bike. You may also part with different stems without incurring costs.

There are many free CAD programmes. For example the free and open source project FreeCAD. It uses a constraint based approach whichch is convenient when one retrieves the geometric specs from a data sheet.

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  • You may be able to do it in CAD. I may be able to do it in CAD. But I was reminded earlier today of the breadth of the users of this network -- there will be plenty who have never heard of CAD. The learning curve of most packages (and the underlying concepts) is steep.
    – Chris H
    Commented Feb 2, 2018 at 21:10
  • Also, you need to know how the different variables effect the ride before the CAD drawings tell you anything.
    – ojs
    Commented Feb 3, 2018 at 10:04

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