Geometry and Lies

Is women-specific geometry on bikes an exercise in patronising female customers? As Lovely Bicycle points out, the market for “ladies’ bikes” tends towards the step-through frame – because the crinoline is such a mainstay of modern womens’ fashion. On the other hand, the woman’s bike features a longer head tube and other tweaks for a more upright position that’s better suited to female anatomy.

Taking the Lane refutes this idea of different body shape, saying that men and women’s proportions are the same, and the women-specific bike is a marketing tool.

I take all of this with a pinch of salt. I think generally bike geometry is poorly understood by customers and bike shops alike. Bike buyers are at the mercy of fashion, such as drop-barred bikes with very low bars, steep seat tubes and tiny clearances between tyre and brakes.

Recently we went shopping for a new bike for T (somewhat wary after the last experience). We looked at a number of bikes and frames. Some bike shops knew what they were talking about, others were full of shit. When I asked one chap if he had experience of bike fitting, he replied “I do it by eye”.

Well OK, he knows his business. But I question any mechanic who claims to work by “feel” instead of measurement (especially when a torque wrench is needed). No doubt the fellow has an idea of what a person on a bike should look like, but what’s important is how the cyclist feels.

I used the bike fitting tool on Competitive Cyclist, and with the absence of a proper bike fitter (really good website – especially the section on saddle fore-aft) I got three options for fitting a bike to my body that improved my comfort immensely. The position of the saddle and the length of the stem made a massive difference – changing those effectively brought my centre of gravity back, taking stress off my hands and wrists and relaxing my back.

BQGeometryTerms800 1

(rather lovely picture nicked from Bicycle Quarterly Press)

I’m not qualified to tell someone else what bike is right for them, but I can talk about what I have learned and what works for me. I currently have two more or less functional bikes (and a load of bits in the shed).  One is a Ridley Triton:

Ridley

(Not my photo – nicked from the CycleChat site. Mine doesn’t have a rack and uses Campag gear)

The other is a Surly Cross Check:

Crosscheck

The shop was fresh out of Beef Gravy Brown, so I got the Robin’s Egg Blue you can see on Lovely Bicycle (I fancy some of those Fat Franks too). Sometimes I look at that brown, though, and wonder what might have been. Sigh.

If I were to pick one it would be the Surly because that’s a more versatile bike, but I like them both a lot. But I bought both for specific uses. The Ridley is (more or less) an Audax bike, so it’s lovely and sporty but still not uncomfortable like a proper race bike, and it can do all-year duty thanks to mudguard clearance. The Surly is technically a Cyclocross bike, but actually it does a bit of everything – fast riding, touring, even off-road. These are my fifth and sixth frames I’ve owned since getting an interest in cycling as an adult.

So here’s what I considered when buying a new frame to fit me.

1. Effective Top Tube

Most bikes are sold on seat tube length, but it’s the effective top tube I go by (and it’s ETT because if the actual TT slopes, it will be longer than the ETT). ST length is measured differently by different manufacturers so it’s not reliable, and some manufacturers just use small/med/large. Get the ETT right for your body and the bike will generally fit, unless it or you are very weird. Mine is about 58 cm, which is the figure I took out of my bike fitting calculations.

2. Seat Tube Angle 

For my size the seat tube angle is 73 deg for something sporty. I bought the Surly because the ST angle is 72.5 deg – trust me, it makes a difference. The bike is a bit more relaxed as a result. You can compensate up to a point for a steep angle with a layback seat post, but generally seat posts with a lot of layback are hard to find (and can put stress on the frame, causing it to crack – especially if you’re heavy like me).

3. Head Tube Length

This will determine how high or low your bars go. With the Surly the fork is steel, so it’s not a problem having a lot of steerer tube sticking out of the top, but it’s a different story with alloy or (shudder) a carbon steerer. You do not want to sheer off your steerer tube while riding.

Headtube

(Image from Bikeradar)

The fashion for road bikes is for short head tubes with very few spacers. This puts the bars stupidly low. I chose the Ridley partly because it’s got a long head tube that raises the bars. The majority of consumers will want a long head tube. Of course if you’re getting a custom frame then you can go with a threaded headset and quill stem that lets you raise and lower bar height as you wish – and looks prettier.

4. Clearance for mudguards, rack, fat tyres

Mudguards will affect your comfort on the bike, because they’ll stop you getting a wet bottom/feet from standing water.

Mudguard fitting will depend on whether the guards interfere with brakes. I have dual pivot caliper brakes on the Ridley which can take mudguards, but they’re a pain. If you really need mudguards, cantilever brakes may be a better choice because no part of the brake comes into contact with the guard – whereas dual pivots will end up touching and moving the guard every time you brake.

Canti

Cantilever – loads of clearance

Dual pivot

 Dual Pivot – will hit the mudguard as the brakes are applied

(Pics from Sheldon Brown and Ecovelo)

My first experience with cantilever brakes (Empella Frogglegs) was really bad and nearly put me off them for life – but with the Cross Check I’m running Shimano BR-550 cantis and they’re just as good as any other brakes. However I wouldn’t recommend cantis unless you are prepared to maintain them, because they’re harder to set up and sensitive to pad wear and cable stretch in ways that other brakes are more forgiving. Modern cantis are a lot easier though, and Sheldon Brown’s site is the place to go for learning about anything bike related.

Choosing cantilever brakes will give you clearance for fatter tyres which will improve comfort – although be wary here too, because some makes still make their clearances fairly tight even though they fit cantilever bosses (the Planet X Kaffenback and On-One Pompino, for example). Stay away from actual cyclocross sport frames.

If you don’t want the hassle of cantis you can use v-brakes, but these need special levers.

5. Headtube Angle, Wheel Size and Chainstay Length

These are less of a concern for me, but they could be very important for a smaller rider or a tall rider carrying luggage.

The headtube angle will be appropriate to the frame geometry – trust the manufacturer to get this right, because it affects bike handling. If you pick a bike with a reasonable seat tube angle the head tube should be OK. However if the HT angle is steep, your wheels are big and you are small, you could end up with toe overlap – the front wheel hits your toe when you turn sharply. This is a pain. The answer is going to smaller wheels and avoiding sport-geometry bikes.

Chainstay length is a problem at the back of the bike – if you want to carry luggage and have big feet, if the chainstays are too short you may hit the panniers with your heels every time your foot comes round. This is also a pain. Generally not a problem for shorter riders since while the other dimensions of the bike change with size, the chainstays tend to stay the same length (since the rear wheel stays the same length!).

6. Bottom Bracket Height

This basically determines how far you can lean your bike without hitting a pedal on the ground. I’ve never had this problem yet. The cross-check has a high BBH for off-roading and because it can be ridden as a fixed gear (you really don’t want to hit a pedal on the road on a fixie). For most people this is a non-issue, although lower BBH may help stability.

7. Material

Steel is springy. Carbon Fibre is laterally stiff and vertically compliant. Titanium deadens road buzz. Aluminium is harsh. There’s a tremendous amount of bollocks talked about frame materials.

All I can say is I chose a steel frame because it can take abuse and isn’t too expensive. The Ridley is (I think) 7075 aluminium and it’s stiff, but it’s not uncomfortable. Both are fine. The comfort on the bike has a lot more to do with saddle choice and geometry than what it’s made of. But I am a convert to steel from now on.

Other Things

Those are all things you cannot change about your bike frame – they need to be right first time. But there are a few other things that you can change after you buy your frame or bike that can improve your comfort.

  • Change the stem for a different reach
  • Adjust the setback of your saddle
  • Find a nice comfy saddle – the hipsters go mad for leather Brooks saddles, although allegedly the quality has gone down as the price has gone up. Brooks have short saddle rails that makes them hard to move forward and back, so I don’t recommend them (I needed a special seatpost to fit a Brooks to the cross check). There are alternatives.
  • Fit fat tyres
  • Try different handlebars. Not all drop bars are the same! My favourite are Nitto Noodle bars and Velo Orange Randonneur bars, because they give a very comfy area for the hand when riding on the tops. Also consider butterfly bars, porteur style bars and others as an alternative to the usual (and uncomfortable) flat bars.

Final Words

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p>Trying to find T a bike that’s functional and pretty has been an exercise in frustration. Really she’d like a thin-tubed, lugged mixte (blame me for introducing her to Lovely Bicycle) but since Reynolds no longer make suitable tubing even for custom frames I don’t hold out much hope. Mixte frames are coming back into fashion, although the mass-market manufacturers have made theirs with ugly, thick tubing. And it’s not the salesperson’s fault that none of their stock is to her taste, although assuming that female cyclist = basket is obnoxious.

But back to the first paragraph – if “women-specific” geometry simply means longer head tubes and slacker seat tubes, that says more about how women value comfort than anything else. Then you’ve got to ask, why don’t men value comfort? Why do we persist with impractical, uncomfortable bikes with garish colour schemes? Why is the mass market convinced we all want to be Lance Armstrong?

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