Hi I accidentally refer to wrong bike fit and purchase online a 20" Frame Mountain bike (XC hardtail)! While the bike is about 20" (51 cm) Frame , I'm about 175 cm (5 foot 9 inches tall and go 79.x cm (31 inch) inseams .

My arm quite lengthy so i don't have problem to reach to handlebar and no need to adjust my saddle . just nice clearance about 0.xx-1 CM from my crotch to the top tube .. it might hit my crotch (and might ruin my future!) so I will need to very cautious when ride off road

Considering all the cost .. I feel that it will be nice if just keep it and do at road and slightly hard terrain .. but it is safe if I go to XC, rough terrain ? what are the risk ? and any suggestion on how to make it safer and just fit to me ?


After moving Spacer https://ibb.co/z4C9rWb

  • 1
    You don't say what kind of bike it is. If it's a road bike that might even be a bit on the small side, though not enough to be a problem.
    – DavidW
    Aug 27, 2019 at 3:57
  • It is Mountain bike (XC hardtail)
    – zzz-zzz
    Aug 27, 2019 at 4:09
  • Depends very much on geometry - what make/model/year is it.
    – mattnz
    Aug 27, 2019 at 6:45
  • 1
    If you are almost hitting the top tube on a modern bicycle when standing over it the frame is probably way too large.
    – Michael
    Aug 27, 2019 at 8:07
  • 1
    To me it looks like the handlebar is too high even when it's as low as it can go. This is a strong sign that the bike is too big. Off road you'll want to have your upper body a bit hunched just that you can move your weight in every direction.
    – ojs
    Aug 30, 2019 at 6:30

1 Answer 1


The odds of your "parts" hitting the top tube is directly proportional to your riding skill and difficulty of the terrain. Off road or trail riding can mean different things to people of different skill levels. A very competent rider can ride a too large bike over terrain a lesser skilled rider may find impassable. So it is difficult to say if a particular frame is too large for you without fully understanding the terrain and your level of comfort riding in that terrain. When I introduce someone to off trail riding I generally try to borrow a bike that is a little on the small side until they get comfortable. Novice riders seem to feel they have more control on a slightly too small frame. It seems to lessen the fear of impacting the top tube or their feet not hitting the ground. My point is that the bike may feel large now but as you gain confidence and skill you may find it doesn't quite feel so large anymore.

  • m Newb and want move from 16" hybrid bicycle and assuming will got 18.5" XC MTB as I want to more adventurous ride but yeah new bike come 20" Frame, everything feel right just only the clearance of stand-over. Haven't ride it in off-road yet as it just come last Sunday .. Do you have any other suggestion ? Just added the riding pic
    – zzz-zzz
    Aug 28, 2019 at 2:56

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