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So far we’ve looked at pedals, wheels, drivetrains (part one and part deux), saddles and handlebars, so we thought it about time to take a look at what they are all strapped, glued, taped, bolted and sometimes zip tied to – the frame.

The variety of frames available is phenomenal; you can spend anything from a couple of hundred pounds to four thousand pounds on a frame designed specifically for any discipline, from hardcore TT frames which offer every available aero advantage, to relaxed sportive bikes which combine handling and comfort to make sure you can still walk after those centuries. We’re going to look at materials, designs, a quick scoot through standards (headsets and bottom brackets) plus a few bits in-between, so let’s kick on…


The Colnago Master X-Light, beautiful and perfect for all day long rides.

In case you haven’t heard, steel is real.  The original tubing of choice and still the chosen material of many, steel is inherently strong, stiff, affordable and repairable.  Steel can be silver-soldered, brazed, welded and bonded making it easily repairable by anyone with some knowledge and a welder (just for the record, this doesn’t mean we recommend anyone have a go…).  The ultimate strength of steel, with a bit of help when in an alloy form, can be incredibly high which when combined with a high fatigue limit means the frame will last a lot longer than comparable materials.  A high quality steel frame can be a frame for life.

The Colnago Super – the ultimate city bike? Quite possibly, but we’d be bringing it in to the office!

Speaking of high quality – there’s one very famous name in the real steel world – Reynolds.  They’ve been expertly manufacturing the steel tubing of choice in the UK since 1841. Reynolds’ 531 tubing was iconic and 27 Tour de France winners over the years have done so riding a Reynolds steel tubed bike.  531 has now been replaced by the flagship steel in the Reynolds range – 953.  953 uses a stainless steel alloy, which gives it a tensile strength in excess of Titanium (up to twice), an incredibly high impact strength (similar to that of armour plating) and incredible fatigue resistance, and it won’t rust either!  The preserve of many custom builders, 953 is available, so keep your eyes peeled.  Don’t discount 853 either, it is air-hardened, very strong and gives a fantastic ride quality.

Ride quality is what steel is probably most famed for – steel is forgiving, it offers a comfortable ride without being too flexy.  People often describe steel as having a lovely ‘spring’ to it, adding to the ride experience and taking the edge off hard road surfaces.  Take a look at the Colnago Master X-Light if you want a bike for every occasion, or the Cinelli Gazetta for track and super cool fixie/single speeding and made from the famous Columbus tubing.


Aluminium is phenomenally popular in frames and components thanks to its low cost, low density and corrosion resistance.  It isn’t as strong as steel or titanium, but because it is less dense, it can be drawn into larger tubes with extra support in key areas which makes it stronger but still at a competitive weight.  Thanks to hydro-forming, new designs and clever tube shapes with constantly variable thickness are possible making aluminium frames stronger, lighter, more forgiving and prettier!

A criticism of aluminium for some can be that the ride is harsh, it doesn’t have the ‘spring’ of steel or titanium, it is inherently more brittle, therefore it transmits more in the way of vibration and impact to the rider.  It is however stiffer, offering a more direct and efficient power transfer relative to weight.  To get round the issue of comfort, Kinesis have incorporated carbon seat stays in to frames designed for big mileages like the Racelight Granfondo to take the edge off the harder aluminium ride.

The Kinesis Decade Tripster, so cool I’m not allowed one.

Aluminium is available in many alloys and ‘models’ and you’ll have seen aluminium as being marked with a code, 6061, 7005 and 7075 and so on.  These refer to the percentage of alloy elements.  You may also have seen a number following like T4 or T6 and this refers to the tempering of the aluminium, the higher the number the higher the tensile and yield strength.  You’ll have seen Scandium frames around too – this aluminium alloy uses a small amount of a material called Scandium (lending it its name) which was developed by the Russians and used to make the nose cones of submarine launched ballistic missiles. The scandium nose cones were strong enough to break through the ice, allowing Russian subs to launch missiles from underneath the North pole!  Scandium offers a more flexible ride making aluminium slightly more ‘springy’ and it also increases the fatigue resistance.

Take a look at the Kinesis KR-510 if you’re after a great value race machine and the KT-415 TT frame for a reasonably priced aluminium TT frame which showcases hydro forming.


Titanium before it gets made in to lovely bicycles.

Titanium still holds that slightly exotic feel because of mainly, we suspect, its cost and also the fact that it has the highest strength to weight ratio of any material.  Titanium is fairly remarkable; despite being half as dense as steel it offers a fatigue level similar to that of steel, meaning that titanium can potentially last forever; incredibly resistant to corrosion, it is used in submarines and frames made from titanium don’t need painting because nothing will happen.  It is also not at all brittle, it will stretch around twice as far as steel and four times as far as aluminium, making it more likely to survive in a crash and also offering a steel-like comfortable ride.

Titanium is however incredibly expensive, it’s difficult to extract and then very difficult to manufacture.  Machining tools need to be extremely strong and used in very specific ways and welding requires an atmosphere of completely inert gas and weld contamination must be avoided through extremely thorough cleaning.  Welding titanium is therefore highly specialised, meaning if a weld fails it is far harder to get it repaired.  Regardless, for many, titanium offers the ultimate ride thanks to its weight, strength and comfort.


The Colnago Flight TT bike utilises carbon to produce aero shapes.

The wonder boy of the frame material world, carbon is now one of the go-to materials for frame builders.  It is very strong, stiff, corrosion resistant and very light.  Because of the way it is constructed, it can also be formed into increasingly exotic shapes. This allows frame manufacturers to make frames strong where they need to be (for example around the bottom bracket and headtube areas) and aero with increasingly sophisticated aerodynamic research and design going in to bicycle design.  Manufacturers are starting to use materials like Boron and Kevlar to increase the strength and impact resistance of carbon.

We get questions about what the 3K/4K type numbers mean with carbon: these refer to the number of common-modulus fibres woven in each strand of the yarn, so 3K refers to 3000 fibres woven into each strand of the carbon yarn.  Layers of these fibres are stacked or layered at opposing angles giving the carbon its strength.  With this laminated structure the carbon can be orientated so it can be stiff in one direction yet flexible in another giving frame builders a raft of options.

The Colnago M10. My kidneys are not worth enough, yet…

Carbon has a very pleasant ride quality, it is stiff and transfers your power efficiently while also absorbing road vibrations and taking the edge off lumps and bumps – this is incidentally one of the main reasons it is used in forks as well to make frames more comfortable.  You do need to take care of carbon, torques must be observed when fitting components as carbon is susceptible to crush damage.  Carbon failures are increasingly rare, but in the unlikely event of a major failure or a big crash a carbon frame may be written off.  In the event of minor damage, there are specialist repairers who can rebuild the carbon layup to its original strength.

Check out the Principia range, The Colnago M10, the amazing C59, and the Time range – some phenomenal frames!


Geometry is one of those subjects you could spend a long, long time on – we’re not going to touch on sizing a frame, but there has been a move recently to different geometry designs referred to as either sloping or compact which is worth a look.  Bikes with either a compact, or as Colnago call it sloping geometry, tend to have slightly shorter top tubes which slope down to a lower point on the seat tube.  The impact of this is you show more seat post and run a larger drop instead of a longer stretch.  If you look in the peloton now you’ll see riders on as small a frame size as they can get away with.  Whereas if you go back a few years you’ll note the bikes had flatter top tubes and were much bigger relatively and the riders rode with much less of a drop between the saddle and handlebars.  It really is a matter of preference whether you go for a compact/sloping or traditional geometry.  Try and sit on a few to see what you like.


I covered this in Drivetrains Part One, so for more information have a look in there, but remember to check your frame details when buying bits for it.  Bottom brackets and headsets are now subject to many standards so make sure you get the correct headset (e.g. standard, integrated or semi-integrated) and the right BB whether it be a BB30, BB90 or a British standard thread and so on.


The Cinelli Mash. I will never be cool enough.

Again this is a brief one, because we could go in to phenomenal depth when looking at all the different designs, but whatever type of cycling you are into, whether it’s cyclocross or audax events, there are now frames designed specifically for those activities.  Cyclocross frames like the Kinesis Crosslight EVO 4 have a raft of cyclocross specific features including; improved mud clearance, a top tube profiled to be more comfortable on your shoulder and carbon seatstays to take the edge off those rocky descents.

If you’ve got the strength and style of ten bears then check out the Cinelli Mash for all your single speed and fixie wants.  Pair it with a pair of rolled up jeans, a weathered beanie, a top of your choice (as long as it’s suitably understated), a satchel/messenger bag with at least one ace but obscure sticker/badge and you’re good to ride wherever you need to go.

Once you’ve won, remember to high five your inner bear. Probably best not to try and high five a real one, but if you have tell us about it!

Then, on your ride home, stop innocuously at the local velodrome/track and beat the lycra-clad-carbon-fibre-based lifeforms before casually remarking that it’s tea time and it’s fajitas tonight so you’d better get home as you don’t want to miss it.  If that’s how you roll.

Finally, if you’re in the market for a high mileage but still competitive frame, there are a few we think you should look at.  Slightly more relaxed than race frames, yet still stiff, responsive and light, check out the Time NXR Instinct, the Principia Ellipse C24, and the Cinelli Pro Estrada all of which combine comfort with performance.  We’ve got limited stock of Principia at the moment but we’ve had word that the full range has left Denmark and will be here soon – we’ll have track, road, cyclocross and TT so watch this space!  They’re lovely frames, designed in Denmark you can expect to see a lot more of them on the roads near you.

The Principia C24T, watch out for more from Principia at PBK very soon. They’re on their way!!

So there we go, a look at frames – we’ve not been able to look at all the frames available I’m afraid, so for the full range take a look at PBK.

In the meantime, what’s your favourite frame material?  Have you got a frame you swear by?  We always like a bit of bike porn, so if you’ve got something special then post a picture on our Facebook site and show everyone!

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