I am looking to buy a new mountain bike and comparing two models with different head tube angles. How big of difference does 1 degree of slackness make? Would an intermediate rider be able to feel the difference?

Both bikes appear to be fairly slack.

  • 2
    It's unlikely that the head angle can be measured any more accurately than 1 degree anyway. Plus, it's the interaction between head angle and rake that determines handling, and the first one doesn't even specify rake. Mar 20 '17 at 0:31
  • @DanielRHicks - Both bikes have the same fork (ish) so I think the rake should be the same. Mar 20 '17 at 0:39
  • I can see significant differences in the two forks. Impossible to gauge from the photos, but there could easily be several cm difference in rake. (My guess is that the rake of the DiVinci is about 2 cm more than the Salsa.) Mar 20 '17 at 0:45
  • 4
    Even if you feel the difference between the bikes, its unlikely you will pin point it to rake or other things. Too many other variables to worry about it. Ride them both and see which feels best to you.
    – mattnz
    Mar 20 '17 at 3:22

There is far more to the stability of a bike than just fork rake and head tube angles. I have designed bikes for a couple of years and the number of parameters is sometimes beyond believe. I have seen research that proved that a bike with a 90 degree head tube angle will stay upright by itself. Aha, you will say than it will be the centrifugal power from the wheels! Nope, the bike had two small skate wheels stacked on top of each other, so no influence there. It turned out that for this bike 'simply' altering the balance by shifting a weight made it stable :

or look for Two Mass Skate Bicycle on Google.

So to answer your question : you will not notice the difference in the headtube. What you will notice is the overall difference in handling between the two bikes coming from the sum of all components in the frame design. So go and test them to make sure you get the one that fits you best.

  • The research you mentioned was just looking at factors affecting self-stability (i.e., the tendency of a bike to automatically steer into a fall - self-correcting) and found a large design space that can produce a stable designs. That doesn't even get into the "how does it feel" design space which is likely much larger. Geo charts can mislead very easily!
    – Rider_X
    Apr 19 '17 at 23:51
  • I did not want to quote entire studies and just used this as an example. Part of the outcome of this study was used in a software application called Jbike+, which does get into the how does it feel category. I was merely trying to hint to the original poster that a 1 degree head tube angle is not detectable..
    – lleto
    Apr 20 '17 at 6:11

TBH 1 degree dont make a difference. It feels the same, unless you change your stem and handlebar and then your bike will feel a bit more of a difference.

  • Gidday and thanks for your contribution. We'd like a bit more detail in the answer, and ideally some citations or links to evidence to support the conclusion - else its just an unsubstantiated opinion and the web has enough of them already. Do have a browse through the tour to learn how SE is a bit different to common web forums.
    – Criggie
    Jun 16 '17 at 4:00

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