North by Northeast


So You Want to Buy a Nice Bike… part 2.5 – More Fit
30 May, 2007, 10:49 pm
Filed under: bike, buyer’s guide to bikes

Let me start by saying there’s much more to fit that what I’m discussing here, though, I’m writing this because I think the information I’m presenting here is a good start to educating yourself on bicycle fit, good enough to help you purchase a bike. This information should never take the place of that from trained professionals like Doctors, physical therapists, sports trainers, etc.

A little more fit detail is available here, at Sheldon Brown’s bicycling cornucopia.

Today will pick up where we left off yesterday – at stem length. The stem is what holds the handlebar to the bike.

Stem length by itself is useless. I could tell you “You need a 75mm stem” and that would be useless advice. The idea of having a certain stem length is in direct response to how far you want to reach forward from your saddle. Once you’ve set your saddle to position you properly over the pedals (see the previous post) then you need to lean forward to reach those handlebars. The biggest determining factor of how far you’ll stretch is “effective top tube length” which is the fully-level horizontal distance from the headset (where the stem attaches to the bike) to the seat post. In the old days, top tubes where actually in this position, but now a days, it’s more likely – especially with mountain bikes and comfort bikes – that the top tube itself will slope. In reality, it doesn’t matter for this discussion where the tube is, all we care about is the distance between the seat tube and the headset.

This distance should be relative to your torso length. There’s no formula, it’s more what you’re comfortable with. If you want an aggressive, stretched out cockpit with fast steering mostly by leaning the bike, then you’d want a bike with a long effective top tube length. If you want to sit more casually, very straight up, steer more with your hands, and your head up, then a shorter effective length is better. On stock bikes, you won’t have a choice of this length, but it will help you find a model or manufacturer that suits your style. It’s a way that bike designers can change the way the bike handles. Also, this length also contributes to the overall wheelbase of the bike (horizontal distance between wheel axles). Short wheelbases handle tighter, longer are a little more comfortable. A short wheelbase brings the possibility of toe overlap with the front wheel, when your front pedal is at the 3 o’clock position. If you’re buying a mountain bike, this is a big no-no. You won’t be able to maneuver around obstacles in slow speed situations. Toe overlap is less of a concern on road bike (my own has some). Consult your bike shop professional.

Finding the reach that’s best for you is very important to your continued comfort. Not for two mile rides, but for 10 and up, comfort is really important. For example, if you’re too stretched out, your upper body will tire prematurely, since it’ll be supporting more of your weight. You can also experience numbness in your hands and back problems (especially if you wear a bag) if you’re too stretched out. If you’re too upright, you’ll have trouble climbing well (your front end will lift up and the steering will get squirrelly), and your bottom could get sore from supporting too much of your weight on that little stretch of your crotch the seat interfaces with. If your knees come very close to your wrists when pedaling, you really need to get bike with a longer top tube.

Once you’ve found a bike with the right reach, you then can fine tune by selecting a longer or shorter stem, if necessary. Stems also come at different angles. If you want to be just a little more upright, select a stem with more rise. If you want to be more aggressive, get a stem with less rise, no rise, or even negative rise. The last is really only something you’d want if you had a bike with a really high front end, like a mountain bike with a lot of front suspension travel.

Next part in this chain is the handlebar. Mountain bikes and comfort bikes tend to have straight or flat bars, whereas your speedier road bikes tend to have what are called “drop bars” which are the curly style with lots of hand positions.

On flat bars (I’ll use this term for all styles of bars that aren’t racing-style drop bars), some are not flat at all. Very popular on comfort and hybrid bikes are “riser bars” which angle up and back a little, not unlike a mustache (these aren’t mustache bars, though. See below). If you need just a little more height, a riser might be ideal. Often a saddle height and bar height that are very close to even will prove the most comfortable. Your milage may very. A totally flat bar will steer faster, as will shorter bars. Bars that are too wide will feel squirrelly, or like you’re trying to steer a longhorn. Also, they may catch on trail foliage, or cars if you’re bravely weaving through traffic. So pick a bar that fits your style, but it shouldn’t be much wider (if any) than your shoulders. The angle of the bar is how much the bar is swept back at the ends, to give your handles a more natural grip. Ignore “bar ends” until you’ve become comfortable with your bike, then decide if they would benefit you.

There are variations on drop bars, but less than flat bars. Mostly width, again, pick one compatible with your shoulder width. To confuse things, you could also consider “mustache bars” which look as if a set of drop bars where run over and flattened by a truck.

Most people just take whatever comes on the bike for stem and handlebar. Really good shops will make sure yours fit you, and allow you to swap them if they do not. Many will do this at no charge, which is to be lauded.

Your hands make contact with the bar via grips (most bikes) or bar tape (drop bars). Most grips that come on a bike are nothing to write home about, but there are some really nice after-market grips available if you don’t like yours. Padding comfort and circumference are the two main characteristics you’d be evaluating. But before you think you should toss your grips or tape, make sure you’re wearing a good pair of bike gloves.

Aside from making us all look a little silly, gloves are as near necessity as a bike component can get. Get a pair, here’s why. First, they add padding, helping to alleviate pain and numbness. They help assist your grip on the bar when your hands are sweaty (and they will be) and they help wick the sweat away. They prevent blisters and calluses on your hands, and they save your skin if you hit the deck. If you’re riding in the dirt, you will fall. Also, when you ride in the woods, prickers and other foliage will scrape over your hands, gloves will help prevent cuts. If you’re riding the road and you do fall, you’ll be very happy to not pick asphalt from your skin. I have a nice Specialized pair that have gel pads strategically placed to alleviate pressure on to major veins in your hands. So far, I like them very much.

Lastly tonight, we’ll touch upon saddles. Notice I haven’t called them seats. There’s a difference. Seats are in cars, on buses, even recumbent bicycles. Saddles for upright bikes and horses. Get it? I guess the difference is back support.

Support is key here. The saddle that will come on your new bike will likely suck. The good news is that there are advanced and comfortable saddles out there, and they don’t cost much. My bike shop actually allowed me to swap mine out for a very nice saddle for no up-charge. I bought a Specialized Avatar, and I think it’s fabulous.

How can you tell a saddle is fabulous? First, you can’t judge a seat by touch. A soft, comfy saddle on the show room floor will not be comfortable on the road or trail after two miles. You want a saddle with firmer padding that doesn’t compress a ton under your weight. That’s because compression leads to more pressure pushing back up on your soft and tender bits. This will make riding very unpleasant.

Commonly, bikes will either come with ultra-cushy saddles for people in showrooms to push in with their thumbs and think “ooh, cushy!” or they’ll come with some harsh, unpadded, light plastic thing that will help keep the overall weight of the bike down. Neither are so great for your bum.

Recently, there’s been a boon of ergonomically designed saddles for both men and women. You should find a saddle that properly supports your weight on your sit bones. Have a seat on the floor with your legs in front of you. Feel those two bones pressing into the hard floor? Those are the bones designed to support your body’s weight when seated. In between those bones are several soft bits that need to be respected. Besides your anatomical, gender specific needs, there are veins that flow through there, too. Sit poorly and things will go numb. Many new seats have gender-specific cut outs so alleviate pressure on those parts. But they’ll only work if the parts supporting your sit bones are the proper width. Too narrow, soft bits squished anyhow, too wide, not enough sit bone support, and possible chaffing. Good seats will come in a selection of widths. My aforementioned Specialized seat, which was designed with input from a urologist, came in three widths. I was a medium.

Once you have a seat that fits, I highly suggest buying a pair of bike-specific shorts to go with that seat. These shorts should have a cycling pad in them, often called a chamois (it’s French – say “SHAM-mee”). Yeah, you could go all Spandex and be aerodynamic. But most likely, you’ll want to wear more normal looking clothes. I do this too. What your do is buy a set of bike shorts that are designed to go under other shorts, or buy a pair of shorts that have a removable padded liner.

Bike shorts (or at least the padded liner) should be worn without underwear. The pad is the underwear: it’s designed to pull sweat off those parts (which will be sweating) to cool them and to help prevent chaffing in this sensitive area. Also, all seams are strategically placed and flat to also prevent chaffing. Add underwear and you’ll up the chance for chaffing and lower the cooling efficiency greatly. It’ll take some getting used to, there’s a slight diaper sensation at first, but you’ll realize this is a comfortable way to ride a bike. Sadly, these are not cheap. You’ll probably spend at least $50 here.

If you wear baggy shorts over your bike shorts, be sure not to wear anything that would impede your ability to move around on the saddle, and most importantly, get off the saddle. Function before fashion. Also, if you’re going to mountain bike, remember you’ll need to slide off the back of the saddle (with your but hanging over the rear wheel) when the going get steep downhill. You don’t want to get your shorts caught on the nose of the saddle.

Alright, unless I forgot something, you should be set with the basics of fit, comfort and safety for buying your new bike. If you’re still riding a bike you already have, you might be able to make some adjustments to make your last while a little more comfortable and efficient.

Next time we’ll talk about all he different kinds of bikes you’ll have to choose from, and where you can ride them.

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2 Comments so far
Leave a comment

Very helpful information! If I want to demo a bike, where can I do that? I would really like to get a feel for a bike before I buy it and I don’t think I can do that if I only ride it for a few minutes outside the bike shop.

Comment by Stacey

Any shop will let you test ride a bike you’re thinking about buying. But the best bike shops will have a selection of actual demo bikes. This seems to be getting more popular. They probably get these for a song from the manufacturers. However, especially if you want a mountain bike, you might find out what the next bike event the shop will be attending. When they bring their demo bikes there, you can get a longer, more realistic demo ride, rather than just going around the block on the road near the shop.

Thanks for reading!

Comment by bwc




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