Health: Are you sitting comfortably?

By Cycling Plus | Monday, May 16, 2011 3.00pm

Saddle fit is the holy grail of ride comfort, but advances in technology mean finding your perfect perch should no longer be an endless crusade.

Since time immemorial it has been held that there is only one way to find the right saddle: trial and error. And while sitting on it is still the only true way to discover if a certain seat suits you, trying every saddle in the shop is time-consuming and could result in a lot of uncomfortable miles before you find your perch.

But with the technology behind modern saddle manufacture tailoring saddles to specific body types and riding styles, it must be possible at last to at least work out which seats you should be trying first.

“The shape is the key,” explains Mike Kalmbach of industry heavyweight Selle Italia. “The materials can make a saddle lighter or heavier, but the shape is the most important part for comfort.”

Smanie’s Marco Capretta agrees: “When a cyclist sits on a saddle there are three points of contact subject to the most pressure: two at the back in the ischial area and one at the front in the perineal area. These points vary according to the size of the pelvis and the muscle structure.”

Another Italian company, Prologo, is taking its research even further. “Some people take the size of the ischial, or sit bones and suggest saddle sizes based on that,” says Salvatore Truglio. “But nobody thinks about the angles of the ischial bones when you’re sat on the bike, but it’s a key point.”

So, how do you go about deciding which shape is right for you? Fizik, a major supplier of saddles to the continental pro teams, has developed its ‘Spine Concept’ system to help riders choose the right model. It recommends a saddle based on the flexibility of your spine, as measured by your ability to touch your toes.

“Comfort is not just about materials in a performance saddle,” explains Fizik’s Alberto Fonte. “What makes the real difference is the correct saddle shape for the right rider. If a rider is flexible, they need a flat and long saddle shape, so we offer the Arione. The Aliante suits someone with a more rigid spine, with the Antares best for those in between.”

Selle Italia’s Kalmbach is reluctant to oversimplify saddle fit: “The rider’s sitting area, upper leg area, riding position and saddle adjustment all have an impact on saddle fit. You also need to analyse and evaluate your body type and riding style. If you move around a lot and ride in several positions, a flat saddle will probably be more comfortable. If you tend to sit in one or two positions, a curved saddle may suit you better. Flat, wide saddles provide better support for cyclists with wide sit bones and larger muscle development and fat areas. However, narrow sit bones can cause a rider’s legs to rub against the edge of a flat, wide saddle, so a narrower saddle platform would be a better choice.”

Selle Italia suggests you start with what you’ve got now: “If you are looking for a new saddle then think about what you don’t like about the one you are currently using. Focus on options that will help eliminate problems by comparing your current saddle with the other shapes available. Keep in mind that padding probably isn’t the answer.”

Which is not to say that materials don’t play an important part in the perfect seat, it’s just that the role they play is more subtle than you might think. Fizik’s Fonte agrees: “Comfort is a combination of saddle shape, amount and type of foam, base materials and rail materials.”

“We have two carbon rail saddles in our collection,” says Smanie’s Capretta, “because carbon is lighter, more flexible and more durable than titanium, but more expensive.”

Selle Italia believes the flexibility of the saddle rail should be a primary consideration. “The more flexible the saddle rail, the more comfortable the saddle. The flexibility helps absorb vibrations and impacts, and the most flexible rail material is carbon. Rails should also be as long as possible to provide the most flexibility and shock absorption.”

Making the cut

Another trend in modern saddles is the use of cutaways or pressure-relieving channels. Even Fizik, who resisted the trend until this year, has introduced its channelled Versus models. And again this is related to flexibility, for better or worse. “Fizik believes that comfort is achieved by maintaining seating surface area, so Versus has the same surface area as our current road saddles. They also use the same base as our other road saddles to avoid any unwanted flex you might get from cutaway saddles,” explains Fizik.

“The cutaway gives the same result as having a central channel, but makes the shape more flexible and less durable,” agrees Smanie’s Capretta, “But that’s not necessarily a bad thing. We recommend these saddles for beginners or people who have specific trouble when pedalling.”

Selle Italia also cites increased flexibility as the reasoning behind its cutaway saddles. “A cutaway allows the saddle to flex more,” says Kalmbach. “It was never intended to put the cyclist’s ‘bits’ in. The more the saddle base flexes, the less the ‘bits’ pound against the saddle base, which is what causes the discomfort.”

How to measure your own sit bones

Of course the measure you really want is between the centres of your ischial tuberosities – the pointy lower parts of your pelvic bone on either side. Many bike dealers have a pad that you can sit on to measure this distance, but you can do it at home too.

Take a piece of aluminium kitchen foil and place it on a carpeted stair. Sit on the foil, lean forward a bit to approximate your riding position, then lift your feet. This should leave a good impression of your rear in the foil, and you can measure between the two points of deepest impression to get your sit bone width.

‘Narrow’ sit bone width would be 100mm or less, medium 100-130mm, wide over 130mm.

A saddle’s width is measured from edge to edge across the top, and Specialized recommends a 130mm saddle width for narrow, 143mm for medium and 155mm for wide. These figures should translate approximately across other ranges, with all other factors taken into account.

Deciding factors

There are some key factors to consider when you go shopping for a new seat.

Shape: Measure the width of your sit bones for a starting point when choosing saddle width, and consider the flexibility of your spine when thinking about saddle length.

Rail composition: The more flexible the saddle rails, the more comfortable the ride. Longer rails are more flexible but materials matter too.

Base material: Nylon and carbon bases absorb more road buzz than plastic, and it is important that your saddle base doesn’t sag over time.

Padding: Most manufacturers agree that padding is not the key to saddle comfort. If you find a saddle that suits you in all other respects, the manufacturer will have put the padding you need where you need it.

Shape shifters

Independent halves: For the ultimate in flexibility – but stability is compromised.

Channelled: To relieve perineum pressure while maintaining a standard saddle base.

Padded nose: Extra padding on the saddle’s nose can help alleviate pressure on sensitive areas, and can be useful on a time-trial saddle, where you ride on the nose.

Flat: Flat saddles are good for riders who like to move backwards and forwards on the saddle to change their position.

Female specific: Often wider at the rear and with a shorter nose to suit the female shape.

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