Giant Defy 3 Composite..Sizing??

Old Cranky wrote:

The Giant store in London have a range of demo bikes and lend them out with a £100 deposit. I think you can arrange to keep them for up to a week.

You should at least keep one for a weekend and do some long rides.

Ooh, thanks - I'll look into that

Grizzerly wrote:

My advice would be to choose a frame which is sold by actual size, rather than uninformative arbitrary designations such 'small' or 'medium'. As a rough guide, the overall dimension of the bike from saddle to extended pedal should be 111% of your leg length, in you case (& coincidentally, mine) approximately 84.5 cm. Subtract from this the crank length (try to avoid anything longer than 170mm if you can) & the desired saddle height and you have a good guide to the frame size you require. This formula has served me well for 50 years & many others for far longer.

It's worth noting that if you select a saddle height of 10cm & a crank length of 17cm then subtract these values from 84.5cm (use a calculator if necessary ) the answer you get will not be 'small' or 'medium' it will be a number of centimetres. If the frame you're looking at isn't sized in the same way, don't buy it.

That isn't actually very useful advice Grizzerly. It's almost as if you want to make buying a bike into some kind of "dark art" where the high priests are the only ones that understand it. It really is quite simple for almost all people to work it out with a few facing a toss up between say small and large. Then it depends on preference and style. Formulas that just give you a number as if everything else about the bike and you are irrelevant should not be trusted. They do appeal to people that think there is a "correct" answer to bike sizing as if your experience, age, fitness, usage and style of riding are irrelevant considerations. Given that, then small medium and large works pretty well as a starting point.

If we want to make cycling popular then let's make it accessible and relatively easy. One sure way to put someone off investing in a new bike worth £1000 or so is to make the size to buy into a calculation best done by a NASA scientist.

So, my advice would be to use the Giant size guide as a guide and then buy the one you that feels the most comfortable. Then stop worrying and go ride it.

I'm not sure telling people that it's too complicated for them to understand and they should listen to what the clever chaps who are selling them the bike is very good advice. In the seventies, most of the mass producers of bikes decided to standardise on three frame sizes, small, medium & large which equated approximately 20, 22.5 & 24.5 inches. People ended up with entirely unsuitable bikes and were lost to cycling. The 111% formula is very simple and allows the rider to make an informed choice, without having to simply accept what the manufacturer wants him to have.

Of course, the manufacturers want to make it seem like a dark art that only they understand, that way they can persuade people that their limited range of mass-produced bikes are actually individually produced for each rider.

Smuggers already knows that he falls midway between the 'medium' and 'small' bikes on offer. That really means that his dealer is trying to sell him a bike which will either be too big for him or too small for him.

Do we really think the best advice is to say "Buy the bike off the experts, it won't be the right size, but they know best."?

Giant sell an awful lot of bikes. They are good bikes as well really good frames. Cycling is not that complicated. Buying a bike does not need to be like getting fitted for a Saville Row suit. I was riding in the seventies albeit as a teenager and on a budget and we rode what was available. Not many people in my club were fitted for their bike. They bought stuff that was about right for them and then got on with it. There are a few people that may need something bespoke or with a precise fitting but the vast majority of people are small medium or large and one of those options perhaps with a longer or shorter stem will work perfectl;y well for them. Or they can choose a slightly large or a slightly small between two of those three options and it will still work for them.

I also don't buy the idea that some people were lost to cycling when sizing was made simpler. Like I said Giant sell a heck of a lot.

You can make cycling into an arcane priesthood full of formulae and odd French words instead of plain old English ones. You can try to make it into an inaccesible elitist passtime defined by its past, or you can embrace the benefits of bikes for all. No nonsense just buy a bike and ride it and enjoy it.