BIKE SET UPS (Made-to-MEASURE)

To help you tailor your Road or Fixed Gear set up and fine-tune your fit, here’s a simple guide to assist you in the process – complete with some helpful links. 

GROUPSET + GEARING

• CRANK ARM LENGTH

http://bikedynamics.co.uk/FitGuidecranks.htm

• CHAINRING SIZE

The size of a chainring (expressed in terms of the amount of teeth on it, e.g. a 52/36T ring) plays a direct role in your bike’s gearing, with bigger rings meaning a higher (harder to push) gear and smaller rings a lower (easier to push) gear. A ‘classic’ road racing set up suited for fast and competitive riders uses a 53/39T professional chainring, while a set up for leisure and sportive riding might use a 50/34T compact chainring, as part of a hill-friendly set up. Personally, we like semi-compact set ups to get the best of both worlds. 

• CASSETTE RATIOS

The vast majority of bicycles come fitted with a 11-28/11-29T cassette (offering a wide-spread of gear ratios) and when paired with a compact chainring, are suitable for most cycling conditions – other than very mountainous riding. If you ride on flat roads all day long, a high-geared close-ratio cassette, such as an 11-25T, 11-27T or 12-27T may suit you best. 11-29T is more versatile allowing for more expansive cycling, while 11-32T is essential for steeper climbs. 

• SINGLE SPEED GEARING

48T front / 17T rear (76" gear) or 48T front / 18T rear (72" gear) are great combinations for single-speed road cycling. If going for a flip-flop hub or double fixed, fixed cogs and freewheels need to be within 1 tooth of each other in order to work correctly with your chain. 

18T is an excellent cog to make you really spin. 17T is great for a more powerful workout. 15T is for those who like to sprint. On flip-flop hubs, going one size larger on your freewheel can also give you that option to switch if your legs get tired. 

Wheels/spoke count

As a rough guide: 

- For riders less than 13 stone (85kg): 28 Front / 32 Rear

- For riders 13stone+ (85kg+): 32 Front / 36 Rear

- For the more aggressive rider, 13 stone+ (85kg+) and/or tougher road conditions: 36 Front / 36 Rear (recommended)

- Fixed gear rear wheels can get away with slightly less spokes because there is little or no dishing. The wheel does not have to cater for a cassette, so it's centered over the hub. 

Contact points

• HANDLEBAR WIDTH

Measure the distance between your two acromioclavicular (AC) joints (the bony protrusions in your shoulder joints). This will give you a rough idea of the handle bar size you require.

For bars measured centre-to-centre, add a further 2cm to your shoulder measurement to allow for the natural extension of your arms when riding. (Add a further 4cm, if bars are measured outside-to-outside).

Riders choose different widths depending on their riding style, but remember comfort is key. It’s also important to consider when choosing your handlebar, a wider bar opens the chest for better breathing and greater leverage, whereas a narrower bar is more aerodynamic. With Sonnet SS bikes we recommend going down one bar size.

Currently, 44cm Nitto bars are only available with a 1 1/8” threadless set up using a Nitto craft 5 stem. 

• STEM LENGTH

To help you select the correct stem, it helps if you have an existing bicycle to asses the suitability of your current set up. 

Choosing your stem comes down to personal choice and riding style. A good indicator of a correct fitting stem is if your handlebars completely obscure the front hub, when you’re on your bike, looking down through your bars with your hands placed on the hoods. If the front hub appears behind the handlebars, the stem is too long and you will require a shorter stem. If the front hub appears in front of the handlebars, the stem is too short and you will require a longer stem. 

With Sonnet frames, we recommend the following stem lengths for cyclists with an average reach: 

• SADDLE SHAPE + WIDTH

We use Selle San Marco vintage saddles on all our builds. Selecting the right model is about finding a shape that fits your body and suits your riding style. Remember, a good saddle should support the sit bones, not the entire bum. 

Shape: choose a waved saddle if you normally sit against the back of your seat and pedal from a fixed position. This profile helps supports you when pedaling uphill, thanks to the rear being raised. Select a flat saddle if you prefer to make greater use of the entire surface, with frequent movements back and forth. 

Width: the more stretched out your riding position and the faster you ride, the narrower the saddle you need. The more upright your position and the slower you ride, the wider the saddle needs to be. When you're stretched out, you place less weight on the saddle, but when you sit upright, the saddle has to support more of your weight. A saddle that is too wide can lead to chafing, and one too narrow can feel like you’re sitting on something very sharp.

• SADDLE HEIGHT

http://bikedynamics.co.uk/fit02.htm#1

http://bikedynamics.co.uk/saddleheightformulae.htm#1

http://www.cyclingweekly.co.uk/videos/bike-fit-and-maintenance/saddle-height-why-you-need-to-get-it-right

• SADDLE SETBACK

http://bikedynamics.co.uk/saddleforeaft.htm#1