Take the 2-minute tour ×
Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. It's 100% free, no registration required.

I read an article stating that the smallest of a particular model of bicycle doesn't fully reflect the original design concept of the model when I was about to buy the smallest (430mm seat tube) of Pinarello FPUNO carbon. Is it true ?

share|improve this question
4  
Even if it is, what is that even supposed to mean? Does it matter? If the bike fits you, is fast, and light, buy it. If it's not, don't. –  Stephen Touset May 15 '13 at 2:45
    
@StephenTouset : I think it is correct. But, since I cannot ride the bike before I purchase it, I want to know if what people said in their reviews is also true for me. –  Aki May 15 '13 at 3:22
6  
Never purchase a bike before riding it, full stop. –  Stephen Touset May 15 '13 at 3:53
3  
I think the question is also asking if reducing a design to such a small size changes the proportions so much that it compromises the intent of the design? –  Neil Fein May 15 '13 at 5:57
2  
Along with the first comment, I would venture to say that if it's true for the smallest, it's probably true for the largest, or if you change the stem, drop the bars a bit, or if slide the seat forward a bit. All these things can change how a bike feels. The fork is always the same size to accommodate the same size wheel and allowing the brakes to reach the rim, So you can't really just scale a bike and have different sizes have the same feel. If you can't test drive the bike, perhaps you can persuade them to do a free fitting, with a free stem exchange to ensure it fits you as best it can. –  Kibbee May 15 '13 at 12:44

2 Answers 2

up vote 7 down vote accepted

The idea here is that a frame is typically originally designed in a 56cm frame, or the equivalent median size for the "average size" rider.

When the frame design is tested and finalized, most manufacturers minimize the changes they make when creating the molds for additional sizes.

This can result in small sizes having a harsher ride than the median, and large sizes having a softer feel, and slightly less power transfer. This is actentuated by the fact that most riders on a small frame have less weight and mass with which to flex the frame, and larger riders have more.

Really high quality manufacturers, like Storck bikes, for instance, use progressively shaped and manufactured tubing, which allows for the ride on the smallest frames and the largest frames to have the same ride charactristics of the median original design.

I am not personally familiar with the manufacturing techniques of Pinarello bikes, but their unique frame and tubing shapes would indicate to me that they would need to design each size independently, which would give a consistent ride characteristic, regardless of size.

Pinarello is known for the stability of their ride, but also for having a heavier than average frame weight. A 56cm frame is typically around 1800 grams, while the Scott Foil or the Storck Fascenario 0.7 G2 are 1050 grams and 1200 grams respectively.

It is more important that the ride characteristics match what you want from the bike, than how much it weighs, of course.

Have you ridden and been fitted on the bike you plan to buy? If not, do so first. (Full disclosure: I manage a shop which sells Storck. This is not an ad, but it is why Im familiar with the topic.)

share|improve this answer
    
+1 for real world examples. –  heltonbiker May 15 '13 at 13:32

I think it's instructive to consider what things can change and what things can't as a bike is sized up or down. Obviously, the tubes can be made longer or shorter. Stems can be made with more or less "reach". But wheels only come in discrete sizes, and there generally are not fine variations in size for cranks, handlebars, brake levers, etc.

There are limited possible variations in BB width, eg, so cranks are apt to be too far apart for someone who's 5-2 and too close together for someone who's 6-8. (Not that it matters that much, since the person who's 5-2 can't operate the brake levers anyway.)

share|improve this answer
    
Actually, those things are exactly what progressive frame designs are all about. –  zenbike May 18 '13 at 17:45
    
@zenbike - Not sure what you mean by that term, but the point is that if the SAME design is used up and down the scale then things will not be right on the ends. And often there are things on the "ends" that can never be fixed -- for the tall guy no wheel significantly larger than the 700c is available, eg (though 24 and 26" wheels are available for shorter people). –  Daniel R Hicks May 18 '13 at 19:24

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.