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CushCore is the #1 best upgrade you can make.

Anyone who knows me and has talked about bikes with me will know I talk a lot about CushCore.

In my opinion, it’s one of the best bike inventions since dropper posts or disc brakes. “But why is it so good” you ask? Well, let me explain.

CushCore does several things:

  • It gives impact protection to your rims
  • It provides sidewall support to stop your tyres from rolling in a corner
  • Because of the above, it allows you to run lower pressure in your tyres for a bigger contact patch and more grip
  • Because of the above, it allows you to run lighter weight tyres to offset th additional weight it adds
  • It puts increased damping into the tyre system

CushCore is a properly engineered product and so much more than other ‘pool noodle’ type inserts from other companies.

Impact Protection
Everyone thinks this is the only point of inserts. Whilst it is indeed a positive quality, the other aspects are so much more important to performance. Other tyre inserts tend to only address impact performance.

I believe the other benefits of CushCore are so much more important that I have run bikes with only a front tyre insert before, where the added grip and control are most needed.

Sidewall Support
CuschCore pulls tight against the rim and extends up a portion of the sidewall. In hard cornering, it supports the tyre and reduces it from rolling.

Increased Grip
Tyre contact patch is a function of pressure in the tyre and nothing else. A lower pressure needs a bigger contact patch to support the weight of the bike and the rider. So low pressures are good, except they often lead to rim damage and tyre roll. CushCore allows you to run super low pressures reducing the effect of the negative aspects.

You can run some very low pressures for super grip. The only limit tends to be tyre roll. As much as CushCore helps reduce tyre roll, in very grippy conditions and surfaces, very hard cornering will try to roll the tyre off the rim and you’ll need to add a bit more pressure. But when grip is low, in very muddy sloppy conditions, you can just keep dropping pressures.

In a race a while back, I ended up running 10psi in the front tyre to find grip in super muddy conditions. There was one off-camber and tricky high line that only some of the Elite riders could stick. But “fastest of the duffers” rider that I am, with the aid of low pressures and CushCore I managed to stick the line too, riding well above my pay grade!

Lighter Tyres
The additional support, protection and damping of the CushCore system allows you to run lighter weight tyres than you normally could. This offsets any weight that the inserts add to the wheel.

In fact, on many of my personal bikes I am now running light weight 2.2″ trail tyres with CushCore XC, running them at the sort of low pressures I would expect in an enduro tyre. It works great!

Tyre Damping
Tyre damping is something I’ve been thinking about for a long time. I even applied for a patent on a system I had developed over ten years ago. Unfortunately, my idea had already been patented in 1935, so people have been thinking about the problem for a long time. And unfortunately, it had some fundamental flaws!

Currently, we have say 150mm of suspension in our bike controlled with very expensive and tuned units. We could talk for hours about the relative pros and cons of different systems and solutions, it is well understood.

However, attached to the end of this system, we have say 25mm of tyre suspension. This is at the most cirital part of a bike, the contact to the ground. This 25mm of suspension only has minimal damping in normal trail tyres, and not much more (but a noticeable amount) in DH tyres. Discussion on this particular subject would not go far with most riders.

See System (1) in my diamgram. Why do we not have damping in this crucial part of our suspension system? Damping would stop tyres rebounding off obstacles and improve grip. See System (2).

Watch any slow-motion footage of someone jumping into a rough rock garden (as well as all the slow mo huck to flat videos loved by bike testers). The first thing their tyre does is rebound off the ground. There tends to be several rebounds before it settles. The suspension cannot deal with this.

Imagine a case where the tyre sticks to the ground on the first bounce.

How much more control would we have?

CushCore doesn’t yet offer this level of damping. But it adds much more than tyres alone can achieve!

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Boosted Bryn Gets Buck Wild on the Swoop

Reece Richards. What a guy!

Commonly known as BoostedBryn, Reece is from Bristol in the UK and I’ve been meaning to try and shoot something with him for a while now.

I kept seeing him sending wild gaps on Instagram and knew he would cut the mustard for a wild video. Lucky for us, he rides for Starling and the big dog Joe McEwan brought us together at Bryn’s local trails to make some magic happen.

As well as being pinned on the Starling Cycles Swoop, Reece was handed a Starling Klunker and a wild fancy dress outfit (not sure it was fancy dress for him though or just the norm!) for us to give a good beating and grab some attention. 60 psi, dangerous drifts and sore wrists ensued. And also lots of laughs… and very strange looks. He actually convinced a chap (fully in character) at Belmont that he was looking to send the biggest gaps on it. Said chap was very worried for his safety!

Making the most of the last of the summer, we headed to some of the Southwest’s finest spots where berms were concrete hard and the tech was loose and dusty.

Reece, and Starling, would love to thank BikeYoke, Magura, Funn, BETD, Sprung Suspension, Morvelo, Ohlins, Cushcore, RyanBuildsWheels and TheOverlandStore.

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What Difference Does Fork Offset Make?

Fork offset is a pretty hot topic, but personally, I think it’s one driven mostly by marketing.

Firstly, the simple part, fork offset only has a small impact on frame geometry; 1.3mm in BB height, 0.2° in head angle. So running either short or long offset on your Starling frame isn’t really an issue.

What is better, short or long? To be honest, I have ridden both short and long offsets, and personally can’t tell the difference.

There is a slight difference in ‘feel’, but I couldn’t put into words what that is. These findings agree with a lot of journalists and other industry types who I have talked to about the subject.

Some people also believe that on single crown forks, the deflection when riding dominates over any small difference in offset.

However, popular marketing-led wisdom tells us that shorter is better, so maybe that’s a good place to start?

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What Difference Does Wheel Size Really Make?

Bike wheel size has caused much debate. We go back to the science it’s a fairly simple topic. I’ll discuss the differences between 29″ and 27.5″ wheels.

I’ll consider one parameter at a time. Tyre contact patch, rollover, dropping into holes, rotational energy, gyroscopic stability, relationship to BB drop.

Tyre contact patch. OK, let’s do the easiest one first. Bigger wheels do not have a bigger contact patch. Contact patch is purely a function of air pressure in your tyres. It is the air pressure that support your weight. Force (your weight) = Tyre pressures x contact patch area. Simple.

Different size wheels may have a slightly different shape contact patches, longer and thinner on bigger diameter wheels, but the area is the same. On a side note, the same is true of fatter tyres, a 2.2″ tyre with 20 psi has same contact patch as a 4″ tyre with 20psi. It’s just that the bigger volume allows you to run lower pressure without damaging your rims.

Rollover. Bigger wheels roll over bumps better, right? Well, no, not really. Realistically, I would consider a bump of 2” (50mm) in the realm of rollover. Anything much bigger and you need to start lifting the bike up and it’s not really rollover. If you consider where a 2” bump hits a wheel on both 29″ and 27.5″ wheels, you can see the difference in angle of attack is negligible, 1.14°.

Bigger wheels don’t drop into holes as much. Realistically, when the bike is moving forward at a speed any faster than a crawl, it’s unlikely you’ll touch both side of a hole. The forward motion means you’ll hit the backside of the hole. In this case, wheel size then becomes irrelevant and we revert to a rollover case.

Rotational Energy. Bigger wheels carry more rotational energy. This is true, but only as a function of the difference in wheel weight. A bigger wheel is heavier by 29/27.5=5% (probably about 0.5% of bike plus rider system).

If this heavier wheel was spinning at the same speed as a smaller wheel, there would be more angular momentum, but bigger wheels spin slower. Think of the amount of ground the circumference of the wheel covers in one rotation. It is proportionally less for a bigger wheel, so it spins slower. This affects acceleration too; other than the tiny bit of extra weight it requires no extra energy to accelerate bigger wheels.

Gyroscopic stability. OK, this is the important one. Although there’s no change in angular momentum, there is an impact on the gyroscopic stability of the bigger wheels. This is because it is proportional to the diameter squared. The gyroscopic stability is the tendency for you wheel to stay ‘in-plane’ when rotating. Like the child’s toy, that stays upright when spinning, it doesn’t want lean over. Take your front wheel out of the bike and spin it up to speed holding it at the axle. Feel the forces to try and move the wheel out of plane.

Now imagine riding along on your bike and trying to lean it over, bigger wheels will make it harder to lean. But also, it means the bigger wheel will not be knocked off line as much by bumps. Anyone who has moved from smaller wheels to big 29″ wheels will have felt this affect. The big wheeled bike is harder to lean over, you need to put more effort in. But once it’s leant over, it’s more stable. People who are capable, will be able to tell you a 29″” is harder to whip off a jump.

Relationship to BB drop. The offset from the wheel axles and the bottom bracket is called the BB drop. For bigger wheels, to maintain a similar BB height from the ground, the drop is more. This drop in relation to the gyroscopic forces acting in the wheels will affect how the bike rides. To be honest, I’m yet to fully understand this topic and have plans to partner up with a final year Engineering student to try and understand this effect.

So, what does this mean for my bike designs?

The Murmur 29″ bike will track and carry speed better (due to gyroscopic stability not rollover). The Swoop 27.5″ bike will be more manoeuvrable, allowing you to hop and pop between line choices. The Twist mullet bike, aims to give the stability on the steering front wheel, and manoeuvrability on the rear wheel. But, it’s not the golden ticket, rather a mid-point between the other bikes.

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Does Bike Weight Matter?

Starling frame weight is about 3.6kg. Our bikes build to about 14-15kg with average components. 13kg if you throw money at it.

Weight is not an important factor for a bike. Wheel weight matters, but not frame weight. It’s just a convenient metric for marketing

How much do you weigh? I’m 80kg, plus say 15kg for a bike and 5kg kit. A total system of 100kg. If you were to swap one of my frames for an absolutely top end lightweight carbon frame, you’d save at most 1kg (plus a 100g lighter wallet). So 1kg in a 100kg system is 1% saving in weight.

Weight matters due to the extra energy you need to put into the system to climb (it’s not just the bike that goes uphill). So 1kg saving is 1%… Well, not quite, we also need to consider rolling resistance, air resistance, mechanical inefficiencies, these all act to reduce the impact of weight. So 1% is massively reduced.

If you are a Tour de France roadie, weighing 45kg, racing a 7kg bike, and a small percentage will affect if you win or not, then maybe it matters. For everyone else, it doesn’t. If you were talking about 5-10kg differences in weight, then maybe there’s an argument there, but not at small weight differences

Wheel weight does matter as it is rotational and on technical climbs you constantly need to accelerate the wheels. Also, the gyroscopic effects of a heavy wheel makes the bike harder to move around. I think it’s these factors that make people think that heavy bikes are hard to ride. Heavy bikes tend to come with heavy wheels.

I do however have to concede that if you constantly ‘hike-a-bike’, then weight becomes a bit more of a problem. But in this case, the nice open front triangle and small tubes on a Starling make the bike easier to carry and this is probably far more important.

You can check out our wheel options for Starling complete builds on the bike builder here.

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What’s the best way to join steel tubes?

There are two commonly used ways to join steel tubes for bicycle construction. Fillet brazing and TIG welding. Frames used to be soldered using lugs, but that doesn’t lend itself well to complex, modern, full suspension mountain bikes.

So, what is better, TIG welding or Brazing? The common belief is that TIG welding is better as it uses a stronger filler material, steel, vs. brass with brazing. The stress engineer in me, notices that you use a lot less of it, and the filler joints are a lot smaller with tighter more stress-raising radii.

There’s also the question of the Heat Affected Zone, HAZ. This is the region of the tube where the heat from the welding affects the properties of the material. Typically, this is where failures occur. Brazing occurs at a lower temperature, but spreads the heat over a larger area. TIG welding is more localised, but to a higher temperature.

Brass is also much more ductile than steel, cracks grow much more slowly in ductile materials. If I were to design a joint system from scratch using any materials I could, I would use a strong base material joined with a ductile joining material using large, stress-dissipating fillets, just like a brazed joint.

‘What is best’ is still not a question that has been answered. Simply put, both ways of joining tubes are fine, as long as the joints are designed properly and the frame structure as a whole is well considered.

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The Secret to a Fast Bike is…

What makes a fast bike? The geometry? The suspension? 29″” wheels? A fancy red paintjob?

The proper answer is the rider. Steve Peat would be quicker than me on a shopping bike. Replace Steve Peat with Loic Bruni for the youngsters amongst you.

Your mate who is faster than you, is always faster than you. Even when you get the spangliest, freshest new bike with all the gadgets and gizmos.

The best and fastest you’ll ever ride is when you’re fully in the ‘zone’. You hit every line you want, rail every corner, pop off every lip, full commitment into the tricky features.

So, lets embrace that. Let’s make you comfortable and confident on the bike, so that you can go as fast as possible. Let’s keep suspension simple and understandable.

If we’re getting technical, anti rise as close to 100% through the full stroke means the bike will react as little as possible to your weight shifts and movements. It will always do what you expect.

Let’s make it strong so that you are fully confident it won’t break. Let’s make it silent so that there’s nothing to distract you from the ‘zone’. Finally, let’s make it beautiful so that you are attracted to it and want to ride it fast.

Not sure if a Starling is the fastest bike for you? Why not book a demo ride?

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Nobody Likes a Stuck Seatpost

Within my frame care page, I mention that you need to move your seatpost once in a while. Move your seatpost!

Steel and aluminium undergo a process called galvanic corrosion that causes them to bond together.

A liberal coating of grease will stop this happening, but in the long run the grease will stop being effective, so you need to keep renewing it.

Modern dropper post mean you don’t move the post regularly. So, one a month just move your post up and down a couple of inches. Once every six months you should remove it and regrease it, sorted.

There’s a great little video about Galvanic corrosion here.

Check out the Starling frame care page here.

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Let’s Talk Standards on Starling bikes

Let’s be honest, the majority of new standards are put in place by big brands to make old bikes obsolete and require you to buy a whole new bike rather than just a frame.

Boost is a classic example, wider is stiffer right? Firstly, stiffer is not necessarily better. Secondly, wide hubs spacing increasing spoke angle, but conversely increase spoke length which reduces stiffness.

For forks, a much wider crown is less stiff. Is all that pain and cost really worth it for a few more millimetres? Is the bike any more fun to ride? Does it make you faster than your mate? Of course not.

So, at Starling, I will do all I can to avoid inventing new standards and make sure I use the ones that seem the best solution to me. As an engineer, it’s my bread and butter to design to the best of my capability within the specification given to me.

I relish the challenge.

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Starling Frame Colours and Matching Parts

Over anything, frame colour is the one decision that seems to be the hardest for my customers. Starling frames are available in a range of colours, and lots of component companies have strong brand colours. Different decal colours, and various anodised coloured parts. It’s understandable why it’s so tricky.

We’ve spent a lot of time in the workshop discussing people’s colour choices. If you follow a few simple rules, I can guarantee a great looking bike.

Pick a strong frame colour, then fit with only black and silver parts. Sorted, your bike looks good.

Dark colours look classy, bright colours lively.

If you want a highlight colour, make it just that, a ‘highlight’. Pick just a few components for highlight; maybe Öhlins fork and shock, or an anodised Hope headset and seat clamp. Gold as a highlight works pretty well in all cases.

A dark or neutral frames, black or grey, works very well with highlights. A bright colour, needs much more consideration when adding highlights.

Don’t try to colour match parts from different suppliers or of different material types. For example:

  • A red Hope headset, will not match red Funn bars.
  • Green custom wheel decals will not match green DVO shock.
  • Even anodizing from the same company is very tricky to match, Fox Kashima is a prime example of this.

If you want colours that clash, that’s fine, but go for it with all your heart. Orange frame, purple headset, green chainrings, blue hubs, multi coloured spokes.

Or just do whatever the hell you want and prove me wrong.

Take a look through all our colour options here.