Sizing a bike and adapting it for your needs
- By London Cycling Campaign on at 07:11pm 18 Sep 2011
- Posted in: Advice, Buying a Bike and Other Kit
- Tagged with: 1, f
Making sure your bike fits
When you try out a bike for size, adjust the saddle to the appropriate height and make sure the seat tube is not at its maximum height nor right down against the frame.
Standing astride the frame with your feet flat on the ground, there should be 2-3cm clearance between your groin and the frame for a racing bike, and 6-8cm for a mountain bike.
Most bikes are sized by the length of the seat tube (which joins the pedals to the seat post), but it's actually the reach, or the top tube length, that's crucial.
Reach can be adjusted by changing the stem and moving the saddle forwards and backwards, but the range is less than the seat height adjustment.
Your bike shop should be able to advise you on the right size frame for you, and most people try out several sizes to be sure about what feels right.
If you already have a bike you're comfortable with, you can measure the geometry (or check manufacturer's specifications) and use this to buy something very similar.
There is a market nowadays for women-specific frames, though there's some dispute as to whether there's value in these, and it's probably true that marketing materials tend to exaggerate the differences in male and female anatomy.
Women-specific designs might have a shorter top tube, or a ‘step-through’ frame. They're likely to have a broader seat, not just for comfort but because women have relatively wider hip bones.
Contact points: pedals, handlebars and seat
When riding your bike, you should only touch it on the pedals, the handlebars and the seat.
These 'contact points' are important, and fortunately are usually quite easy to change.
If you're buying new, you should get these right at the time of purchase.
If you do want to change any of the components on your bike, discuss this with the bike shop before you buy the bike.
You might be able to arrange a free exchange, or an upgrade, where you pay the difference.
There are many and various saddles on the market, and it is a matter of personal choice which will suit you. Female-specific saddles tend to be wider at the back and shorter in length. Solid leather saddles can look very hard and uncomfortable at first but with time and maintenance the leather eases and adapts to your shape, making them very comfortable in the long term.
Mattress saddles are often seen on traditional English three-speeds or shopper bikes, and have multiple springs running through the frame of the saddle covered by a layer or felt or horsehair and topped with leatherette or vinyl.
Gel saddles have an insert of viscous material between the base and covering material (usually lycra, vinyl or leather). These can also be very comfortable as the gel insert moulds itself to your shape, creating a ‘jelly cushion’ effect.
Flat and drop bars are both fine for city riding, although if you choose to use the dropped part of drop bars your position may lead to reduced visibility. However, if you intend to ride for longer distances drop bars may be more comfortable – the variety of hand positions they offer can provide some relief.
You can adjust the height of your saddle and how far forward it sits on the seat pin. The saddle should be high enough that when you are seated on the bike with your foot on the pedal at its lowest point, your leg is almost fully straight, and you should be able to touch the ground with your tiptoes.
You might wish to have your saddle a little lower so that you can easily touch the ground if you are starting out, and move the saddle up when you are feeling more confident. Knee pain when cycling can be the result of a saddle that is too low.
Flat pedals as normally seen on mountain bikes are fine for commuting with trainers or a similar flat-soled shoe. Toeclips and straps allow you to pull as well as push on the pedal, allowing greater efficiency.
Clipless pedals such as SPDs (Shimano Pedal Dynamic) are used in conjunction with cycling shoes.
Based on the idea behind ski bindings, a metal cleat on the shoe sole sits into the pedal, binding your foot to the pedal in the same way that toeclips do but allowing you to undo them by flicking your foot out sideways.
However, it’s advisable to practise away from traffic as almost everybody falls off at first.