Early Retirement Extreme Forums

Early Retirement Extreme Forums » Transportation Questions

1. 

   frankwolf
   

   Novice
   Joined: Dec '10
   Posts: 14

   Dear all,

   after I thought I would fork over a sum like 1000$ or eventually even more to a local bike retailer I was thinking again - and actually my amortization calculation does not work out right now and so I decided to look for a cheaper yet technically well-maintained used cyclocross bike for 500$ max.

   Since I have read about bike-ergonomics - I would like to ask you about your experiences. How important is the frame size, the length of the top tube and/or stem length?

   How did/would you choose whats good for you?

   One advice I read about was that the frame size should be such that the its size should be about 2inc (5cm) smaller than ones standover. Thus for me that would be something like 21".

   Do you agree with that measure? What are your ideas about top tube and stem length (arm length? only dependent on how sporty one likes to go?)?
   How much do ideal ergonomic measures matter and how do you determined/would you determine them?

   Thanks for your comments!

   best regards,
   Frank

   Posted 1 year ago #
2. 

   flitteringleaves
   

   Novice
   Joined: Dec '11
   Posts: 14

   There are many different ways to fit a bicycle. The reason you want an appropriate frame size is so that you do not need to adjust the other factors too far. For example, if your frame is too small, sure you can get a longer stem to compensate and raise the seat very high, BUT your handling will be off and the bicycle will ride strange. Same if you have the opposite.

   I think this article explains some a little better than I can: http://www.ecovelo.info/2011/08/20/from-the-archives-bike-fitting-is-an-art-not-a-science/#more-30066

   My recommendation is to go shopping at a bike shop and test ride some bicycles to get a feel of how a given size bicycle feels. Then go find a used bicycle of a size you found to be good.

   When I built my current bicycle I got a frame that was on the higher end of the sizes recommended by the manufacturer for my height because I felt cramped on my old bicycle. It did take some adjustment but I enjoy how it is now, even if it's a little too large for my by most people's standards.

   EDIT: Are you actually planning on using the bicycle for cyclocross or just looking for a good commuter bike?

   Posted 1 year ago #
3. 

   C40
   

   Master
   Joined: Feb '11
   Posts: 573

   The bike size and fit are very important. The more you ride, the more important fit is. And likely, the better your fit is, the more you will ride.

   There are some pretty good examples of bike fit calculators. Here is one I remember working pretty well and having a lot of information:

   http://www.competitivecyclist.com/za/CCY?PAGE=FIT_CALCULATOR_INTRO

   The less used to riding you are, the harder the decision of frame size is. Since it's new to you, expect to make adjustments as you go. You will be able to use a more aggressive riding position as your flexibility and certain types of strength improve. (that's better if you'd prefer to go faster with the same exertion)

   If I remember right, some folks will say that a cyclocross racing frame should be 1-2cm smaller than what you would use for a road frame. If you're going to use the bike for transportation, ignore that advice. (That advice is only because being positioned further forward might make it easier to "steer" around corners in cyclocross racing. The difference being that in a cyclocross race, you'd be navigating sharp corners on grass and mud as fast as possible.... much different than the type of turning/riding you do when commuting)

   Generally, bike sizing is done by getting the correct top tube length. If you have the top tube length correct, and you're fairly flexible, the seat tube length will work out ok. (the heat tube height can also be of importance, especially now as frame makers are using a wide variety of HT lengths). The thing is, knowing what top tube length you want can be hard without a lot of riding experience and position experiments, or without the help of a good bike fitter. A bike shop salesman is often NOT going to give you good fit advice (Definitely don't just take their word for it if they tell you something like to just stand over the bike and if there's 1-3 inches clearance, you're good). There are very good bike fitters scattered around the US. Here's an example: http://cronometro.com/biodynamic-fit/. Bike fitters can be expensive and it can be hard to tell what you're getting into before the actual fit.. The examples of people you will hear about from word of mouth as being really good are generally the expensive ones, and you don't need that kind of an in-depth fit yet..

   I hope this helps some... feels like I I've just been rambling.

   Posted 1 year ago #
4. 

   jacob
   

   Expert
   Joined: Jul '10
   Posts: 3,298

   Framesize controls the distance from the seat to the handlebars and has to do with the length of your torso/arms. It's somewhat flexible. A smaller frame makes for a more aggressive riding style. A larger frame makes you more stretched out. It's important, because it's hard to correct the distance by moving the saddle or handlebars in the horizontal plane---often it's less than an inch of movement.

   It's easier to deal with a frame that's too small than one which is too large, so if you gotta err...

   Beyond that, the correct saddle height (very adjustable) is the single most important factor.

   Don't worry too much about getting the fit absolutely correct---it'll change with your riding style (from racer to cruiser to slowpoker).

   Posted 1 year ago #
5. 

   Ego
   

   Master
   Joined: Nov '11
   Posts: 752

   My wife and I have toured for years at a time on slightly misfitting bikes I bought at thrift stores. Older 1980s & 1990s good quality bikes are bombproof and will last forever. You can find them for next to nothing.

   The best thing about them is that they are pre-planned-obsolesences. They can be repaired with a few simple (non-specialized) tools.

   And nobody wants to steal them or their components.

   Shocks, sealed bearings, brake-lever-index shifting, lightweight wheelsets, carbon fiber ... all gimmicks designed with a short lifespan.

   Most important question: How do you plan to use the bike? Commuting? Off road? Racing? Leisure?

   The faster you need to go the less upright you should be on the bike. Look at a time-trialist. Compare his posture to the upright commuter.

   In general you want a little bit of clearance between the bar when standing and you want a slight bend in the knee with the peddle at the bottom of the stroke when seated. When riding you want to watch for too much weight on the hands (shoulder, neck & hand pain) and too much weight on the saddle (saddle sores).

   Beyond that, it's not that important.

   Happy cycling.

   Posted 1 year ago #

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