Tech & Sizing

Geometry

 

 

Construction

We don’t believe in bikes that are so highly specialised they can only effectively do one thing – equally, we eschew the ‘Swiss army bike’ approach taken by some. Striking a balance somewhere in the middle seems about right to us. Therefore you see appropriate frame fitments for the bike’s purpose. Tubing choices that are right for the intended use – not too beefy nor flimsy – and appropriate to each frame size. Geometry which does what it’s supposed to do – provide a comfortable, efficient yet responsive ride.

Our bikes are made in Taiwan by a highly respected steel frame builder from only the best quality steel tubing available. We use a mix of Reynolds and proprietary butted 4130 cro-mo alloyed steel tubing to provide a beautiful responsive ride and lasting comfort. We work closely with our manufacturer because they are the best at what they do. They construct frames which represent the pinnacle of steel frame manufacturing in quantities and at a price unrivaled elsewhere.

We use lugs where we can, they’re still the most elegant and reliable way to join tubes, but for the geometry we use on many of our frames lugs just aren’t yet available in the appropriate angles and sizes. Therefore frames are TIG welded, which provides a neat and strong way of joining tubes.

We pride ourselves on a very low rate of failures. Having now produced over 1000 framesets, we have had a total of three frame warranties on our steel frames. A few of the early Swift forks also bent, but since a design revision we have had no further issues.

Big Wheels

So what are 29 inch wheels and why would you want them?

What they are is easy – 2 inch (or wider) tyres mounted on road/hybrid diameter rims.  This makes for a wheel which is around 29 inches in diameter, as opposed to the standard 26” inches.

The single biggest reason for using this wheel-size is to make a proportionate fitting bike. 26” wheels only ever became the standard for mountain bikes because the old cruisers (which when converted became the first mountain bikes) used this diameter of rim – they were the only tyres available with enough volume. These were not bikes designed for performance riding, and it took over 20 years until someone said ‘hey, these little wheels just feel too small for grown adults’.  In our experience anyone over about 5’7” (170cm) will generally feel much more proportionate and balanced on a 29” wheeled bike.

In addition to fit, there are a number of other benefits of larger wheels.  A bigger wheel makes anything in front of it seem relatively smaller, which means it’ll roll over the top of it more easily. Because they’re bigger, they maintain momentum better. A differently shaped tyre contact patch (longer and thinner compared with a 26″ wheel all else being equal) means better climbing, cornering and braking traction.

Of course, there are downsides. The primary ones are weight, and a somewhat limited selection of parts.  The parts selection for 29”ers is rapidly growing, tyres, tubes, forks and rims are readily available online and increasingly in local bike stores. Weight is another issue, this one a bit harder to get around. Of course, a bigger wheel is always going to be a little heavier.  However, if lighter wheels were really the only goal we’d be riding super light 20” wheels wouldn’t we?  A lot of riders are trading a little weight for better fit and riding performance.

Ultimately the easiest way to see whether they’re for you is to give them a try for yourself. Check the dealer section to find somewhere you can test ride a Singular.

Talkin’ about trail

One of the most critical elements dictating how a bike rides is ‘trail’. This figure describes the distance between the point at which an imaginary line through the middle of the steerer tube would hit the ground, and the point at which the tyre actually hits the ground.  The longer this distance, the slower is response to steering input – and conversely very short trail tends towards ‘twitchy’ steering.  As you can see from the picture the more offset (rake) the less trail.

What most people are after for general mountain biking is a fairly happy medium, which I feel is found at about 70mm of trail.

The Swift was originally designed to try to give as close as possible steering response between an early 80mm Reba and the stock rigid fork. Two things have changed since that time; first that suspension forks have got longer and have increased offset, second that my thinking about handling between rigid and suspended setups has changed a little. I’ve come to think that more neutral feeling handling with a suspension fork is not such a bad thing – gives more confidence when going hard at rough terrain as you are tempted to do when having suspension up front. When rigid a quick steering response to pick a tight line is necessary.

The earlier forks at 485mm long/48mm rake meant that when a Reba at 80mm/39mm offset was fitted the front end actually drops (accounting for sag – any designs which assume a suspension fork allow for 20% sag) keeping trail fairly constant. The current forks at 470/45 mean that once a 100mm fork with ~45mm offset is fitted trail increases a bit and just takes the edge off the steering quickness.

In any case, there is more to how a bike rides than just trail and steering response, though it is a very important part of the overall package. I like to think that for folks who tend to like their steering on the quicker side of things the bikes ride very well.

Another consideration regarding trail is loaded weight. Our frames which are designed with some touring in mind (the Peregrine and Osprey) have steering geometry which is optimised for use when carrying a load on the front of the bike.  The Peregrine is a versatile beast, and can use any tyre from a 50mm dirt tyre, to a 32mm (or even less) road touring tyre. With the change in tyre size comes a change in trail, the smaller the tyre, the shorter the trail and the quicker the steering. So with a big tyre the Peregrine is more stable and better suited to off road riding. With a narrower tyre the handling gets fairly quick. The benefit of this is that when a front load is added (which naturally slows steering response) the steering stays reasonably responsive.

This approach to low-trail geometry for front loaded bikes is taken to it’s logical conclusion with the Osprey. It is supplied with a choice of a standard fork for regular riding, or an extra long offset (60mm) fork for low-trail when using a front rack supporting a loaded bar bag.

Tensioning chains – eccentrics?

Forgoing derailleurs, whether for singlespeed riding or internally geared systems, requires an alternate means of tensioning the chain.  There’s a few ways for doing this, each with their pro’s and con’s.

The easiest and traditional way to do it is to have a long dropout with a horizontal section to allow fore and aft adjustment of the wheel.  This is a great and simple way to do it, also lightweight.  Problem is if you want to use a disc brake you throw the brake adjustment out of whack every time you tension the chain.

Eccentric bottom bracket shells have been in use for decades to maintain the tension of the timing chain on tandems.  It makes sense to employ the same idea to a derailleur-less bicycle  – a neat, elegant and hassle free solution.  The frame’s bottom bracket shell is oversized and fitted with an insert which has the bottom bracket thread milled off centre.  Therefore rotating the insert allows you to tension the chain.

There are also a few possibilities for holding the eccentric in place. Pinch bolts on the shell work much the same as a modern stem clamp. Set screws thread through the shell and set the insert in place. ‘Bushnell type’ eccentrics have an expanding wedge, like an old quill stem. We use a set screw type as it’s the simplest and most reliable. Pinch bolts can stretch or snap, expanding wedges are prone to noisiness.

Sliding dropouts basically take the vertical dropout of a modern bike and give it a way to slide backwards and forwards in relation to the frame. This has the advantage of keeping the disc caliper in the same place in relation to the rotor when adjusting chain tension.  When well designed they can be solid and slightly lighter than an EBB. The downside is that they can look a bit kludgy, and can require up to six bolts to be tightened and loosened for chain adjustment – whereas an eccentric only has two.

We’ve chosen to use an eccentric bottom bracket for our single/internal geared frames as the best combination of reliability, functionality, and clean looks.