I'm planning to buy a bike. Based on my height (I'm 5 foot 6 inches / 167 cm) people suggested me to go for anything between 17"-18" frame.

When I calculated its coming as 17.5"

My dilemma is if I go for 17" (43 cm) as the frame is readily available is that right fit? Does 0.5" (12.7mm) makes a big difference in terms of comfortability and ride quality?

I'm looking for MTB or Hybrid. I'm 27 and my height is just below average.

  • 2
    There's so much more to bike fit than your overall height. Yes its a good indicator, but arm and leg length come into it too. Your "rule of thumb" frame size is probably a great starting point, but you have to try a couple to see what feels right. If you're buying sight-unseen, best of luck to you. Also, please consider using units when posting measurements - we're not all in your location.
    – Criggie
    Commented Feb 14, 2016 at 6:56
  • 5
    Possible duplicate of Frame sizing: "medium" vs. inches vs. centimeters and you can use the search box on the top right of every page to find the numerous questions about frame size
    – Móż
    Commented Feb 14, 2016 at 8:00
  • 1
    Another thought - what kind of bike frame? Road, MTB, or Hybrid? And (don't take this the wrong way) but are you still growing? Most people over 20 should be pretty much full sized, but younger than that and you might need to allow some slack.
    – Criggie
    Commented Feb 14, 2016 at 8:01
  • Take the 17'' which is a good choice for an MTB or hybrid. For a typical road-bike you could take the 18''but still after trying it out.
    – Carel
    Commented Feb 14, 2016 at 9:09
  • Thanks so much for guidance. I finally got a hybrid as im mostly doing tarmac roads and long distance. Found 18 inches pretty comfortable. Hope will be able to join the league with my experience soon. Cheers, happy and safe rides!!
    – Vishwa
    Commented Feb 14, 2016 at 17:15

7 Answers 7


Common wisdom is that upper body length, true inseam and riding style are important to bike fit, as is where/what you will be riding.

Riding offroad needs more frame/rider clearance than street or park riding. You should have 4 inches/10 cm for true off-road mountain biking, and 1-2 inches (2.5-5 cm) for road or commuter riding.

One of the better bike fit sites: http://www.competitivecyclist.com/Store/catalog/fitCalculatorBike.jsp


Fit is an incredibly subjective issue. The size of the frame is only one factor in fit. You then have to address stem length and height as well as saddle height and position. Geometries differ across brands so one cannot simply use height as a measurement as one's leg length will be the dominant factor. Firstly, what type of bicycle is this? Road or mountain? Secondly what is your riding objective? Competitive, recreational or commuting? These sites might be of some help. https://www.cyclingweekly.com/fitness/bike-fit/set-up-new-road-bike-370764 https://www.rei.com/learn/expert-advice/bike-fit.html

  • There are bike size charts based on height. You can google them. For ex, a 54cm bike should fit a 5'7"-5'9" rider, and a 56cm should fit a 5'9"-5'11". If that rule doesn't work, then it can be a risky when trying to look for the right size. Not all sales people know whether a bike fits the customer, bike fitters can charge you even if you bring a bike that's too large, and some stores have a final sales policy. If that's the case, then it's probably safer to go for one size smaller as you can use a longer stem or longer reach handlebar.
    – Brian
    Commented Feb 16, 2019 at 4:33

The frame model is an influencer of riding conform which you mentioned later in your comment.

I'm looking for MTB or Hybrid. I'm 27 and my height is just below average ;)

My suggestion for you is to take it simple by going to a store which offers bikes for test and then test the following before confirming the buy.

  1. Test the three 17, 17.5 and 18
  2. While you’re seated at a stop, your both feet should be kept flat-footed on the ground
  3. Do you feel natural in your back, neck, and legs while trying that size
  4. Choose a comfortably padded seat
  • While you’re seated at a stop, your both feet should be kept flat-footed on the ground This isn't true in most cases
    – Paul H
    Commented Aug 8, 2019 at 15:31

Old school answer is that when you stop you stand. You should have an inch of clearance from the frame and your crotch.


Under 1" is not significant difference. With saddle rails, sloped seatpost and different stem lengths or angles you can offset +- 2" in typical frame geometry. Over 2" might cause problem with steering as stem would be either very long or short.

It is unlikely you'd notice a difference between a 17" and 18" frame if saddle and stem were setting accordingly.


For a comfortable ride you really need correct frame size. Based on your height I think 50cm - 53cm frame size will perfect for you.

You can calculate your frame size by your height here.

  • Hi, welcome to bicycles! When answering, you should consider your answer in the context of previous answers, which have already discussed that a simple height measurement isn't really sufficient for sizing a bike.
    – DavidW
    Commented Aug 8, 2019 at 12:34

Frame size is a very important issue, but don't stick to little details. That one inch will not really be the main factor of your final decision. You will be equally able to ride both with the right saddle height. What is very important Is for you to find and test some bikes around 17"-18" and choose one that will give you an upright riding position and won't force you to lean towards the bars to gain optimal control. Also keep that in mind: if you go for 29" or 27,5", 17" will be a better choice, but if you go for 26", 18" bikes will suit you better. Make a list with the bikes you are interested in, find sellers and test them. Don't be afraid to go for 29" or 27,5", 18" if you find a good bike. Changing a stem can fix everything. See ya on the trails!!

  • You seem to be assuming the asker is buying a mountain bike (reference to an upright riding position, different wheel sizes and being "on the trails") but the question says nothing about that. Commented Jan 13, 2019 at 18:10

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