Vital MTB Forum Hot Seat: Joe McEwan, Starling Cycles Founder

I think fore/aft balance of suspension is one of the key thing to set up a bike correctly.  You see far too many people setting their bike up based on 'getting bottom out once per ride' rather than chassis dynamic stability.  In the simplest terms I set a bikes suspension by riding along and pushing down super hard towards the ground 90% legs/10% hands (or how you ride).  The bike should move downwards parallel to the ground.  This can be achieved lots lots or little sag, whatever your prefer, but this fore/aft balance is what means the bike behaves correctly on rough terrain.

So if we use the same argument, then it doesn't really matter whether you run a longer fork than rear travel, the balance is still key.  A hardtail is a good outlier; I actually find it super hard to ride hardtails as they 'pitch' so much with suspension travel.  I always end up running super firm forks to try and achieve some kind of balance.

However, there is a little bit of me who want to run a bike bike with loads of rear travel and a shorter travel fork, like DH bikes used to be in the olden days.  In this case, we would run the rear a little softer and in compression the bike would slacken off.  This makes sense, a slacker bike in rough terrain as suspension moves.  This is the opposite to over-forking where the bike could potentially steepen up in compression like a hardtail.  

Which brings me full circle and I just end up concluding, the most important thing is that you understand how the bike rides, even if it doesn't make 'scientific' sense.  Again the rider is way more important than the bike.

“Brake Jack” is supposed to refer to negative antirise, where your bike stands up horrifically under braking because the wheel is effectively rotated backwards when the suspension compresses under braking, but basically no bike has actually had to deal with this since the 90s. I think what most people actually interpret as brake jack is their rear suspension stiffening from chain tension/pedal kick, causing the bike to stand up as if it had negative anti rise. These days single pivot bikes are not doing this any better or worse than 4bar bikes so I think it’s largely a non issue. 

Hi Joe,

Another gearbox question, inspired by your Sturn DH bike. Totally loved the look of it- simple, no-nonsense, get-it-done bike. However a single-speed DH bike was never for me. 

As a long time convert to gearbox DH bike (Diamondback Sabbath and Zerode G2) I find the current industry moves to using the Pinion Smart Shift gearbox fascinating yet puzzling- we are getting MORE complex not less! E-shifting to facilitate shifting under loads, output cog in the wrong position (as you have said earlier), constantly meshed gears that are “draggier”, doesn’t seem like the future that I had hoped for.

So, what are your thoughts on a derailleur-in-a-box style solution (Honda, Petespeed, Trinity, etc.)? Although not maybe as “mechanically pleasing” do you feel it could be done in a simple, clean, more efficient manner? 

Cheers!

I would definably not be designing something like that under the radar!!!

Your bikes look simple but simplicity can be really difficult to achieve. What is the toughest constraint/requirement that you have to deal with in the design and manufacture of your bikes and has this changed since you started making bikes?

Simplicity is hard to achieve.  Its always easier just to keep adding stuff to solve a design problem, rather than going back to the start each time as assessing what is really required.

But that make me sound clever.  In reality, the restraints of the manufacturing in steel, along with my poor 3D CAD skills mean a simple solution is pretty much all I can achieve!!  Also some of it comes from me starting to get upset when complexity and lack of elegance starts coming into the design, a little bit of autism I think!

Toughest requirement is always just trying to package everything into the available space.  We still haven't entirely solved this with water bottles, they work but not perfect.  We're working on a solution, but it does risk some of the elegance, so maybe back to the start again.  At least we're not pressured by model years.  Our bikes work great, we will only update when we are totally sure we have something better.

Great question. 

Love the steal is real, simplicity is efficiency, and no-marketing BS vibes Starling is putting out. Your bikes have been high on my list for my next purchase for awhile now. But, since my current bike's style and geometry is very close to the Mega Twist, and I agree with your point that the rider often makes more of a difference than the technology, I'm holding out for gearboxes to get better. Implement this on the Mega Twist and you can have my pre-order money now!

(This is a partial joke and by no means to be taken seriously 😆Joking aside, I'm really looking forward to this frame)

Did you know one of the BLE owners on the other site was converting theirs to a dingle speed using a quick release on the frame to allow gear changes trailside? Is this something you would consider offering?

Ha, yes.

A customer used QRs on the bolts that clamp the eccentric dropouts.  This allowed him to quickly adjust the tensioners, and run two different sized cogs.

I love customers doing this kind of stuff.  It what I did with all my bikes before Starling.  The world would be a boring place if everyone was the same and had the same needs...

But we have no plans to do this!

Starling Murmur owner here. I used to think I wanted progressive suspension. Bottom-out resistance sounds like a great idea, and I like to think that I hit the odd big jump or drop that warrants it. I bought my Murmur as part of a special offer that included a Cane Creek DB Inline Coil shock with a progressive spring, and I was stoked because my biggest fear about moving to coil had been about the lack of progression. I was very happy with the bike, and the traction and ground-tracking ability of the rear was amazing. However, I felt like I struggled to get it off the ground, to bunny-hop and jump around. I checked the spring rate multiple times using the calculator on Cane Creek’s site and measured the sag as best I could, and everything seemed to suggest I had the correct rate (500–610 lbs progressive spring). I wondered if it was some other characteristic of the bike that made it behave this way. Eventually I dialled the compression damping most of the way in and the rebound damping nearly all of the way out, and that got it closer to the feeling I was chasing. But I also started wondering if maybe I needed a more linear spring rate. I heard Cy Turner talk about how he had been removing volume spacers from his fork and increasing the pressure slightly to get more support in the mid-stroke. I tried this with my fork and ordered a linear 550 lbs linear spring for my shock. I’ve only had one ride on it like this, but it’s so much better for me. My damping settings are back towards the middle, and I feel like I have much more to push against when preloading for a bunny-hop, pumping the terrain, etc. I would say my old spring was far more “wallowy”. Admittedly I could probably have achieved much the same effect with a stiffer progressive coil (the 550–670 lbs), but I would probably never use the last 15% of travel in my regular riding. It might be the better option if I ever spend time in a bike park riding big jumps and drops, but I’m unlikely to have that chance anytime soon. I’ve got a mate who likes to straight-line everything and keep his rubber on the ground, sitting into the back of the bike, and he probably would have preferred my original setup.

So based on my experience, I would say there is nothing inherently “wallowy” about a Starling or a linear spring rate. “Wallowy” to me would imply that it’s spending too much time in the range between 30% and 60% of the stroke. The Cane Creek progressive coils only get progressive from 50% into the stroke anyway, so I don’t think that would fix a “wallowy” feeling. I won’t claim my setup will suit everyone, but I don’t think you need to be afraid of a Starling frame being “wallowy”. There are so many ways to tune a shock to overcome any wallowing, and the predictable linear nature of Starling’s frames mean that you can tune away without worrying about compromising the kinematics.

Yes, VAT can be paid at customs when you import bikes to the EU, not a big deal. 
BUT I live in Austria and we also have to pay an extra on top of 15%  for a full bike (due to weight) and 7,5% for frames (due to weight). 
The UK has such a vast landscape of great frame builders but paying that extra of 15% holds back a lot of people in the EU. 
 

the morning I was eyeing starling frame they dropped the bomb video, already +1 will point to purchase it

Great video, I appreciate the time and effort that goes into that.  I would be interested in the results from a few carbon and steel frames.  The results can easily be opposite depending on which brands that are tested.

I can tell you that moving to a Rootdown from a Meta HT Chromo a few years ago, not all steel frames flex the same. The Commencal almost felt like a butter smooth rocket ship on any terrain, with the seat stays forming a triple triangle similar to a GT. You could actually see the bowed stays flex to give the bike a ton of compliance. The Rootdown certainly mutes shock and vibrations compared to an alloy frame, but that frame does not have a ton of flex. It was almost shocking the difference on the same trails.

It'd be interesting but time consuming to repeat this test but with increasing weights from 1-20kg

I'd have thought that deflection vs weight will plot a curve. My instinct would be that steel would be a lot more linear than carbon or aluminium and so the differences would be more pronounced at lower weights before converging somewhere at a higher weight.

I'm a big fan of testing, that part was cool. But missing some key points if the goal was to really compare steel to carbon as a frame material. (Sorry if this was covered at some point in the video, but it was too slow so I skipped around).

1) If you want to compare stiffness of different frame designs, that is great. But the frame shape, pivot locations and size, rockers links, etc all play a huge part in the overall stiffness numbers. To really isolate frame materials you would need two identical frame designs, with one made from carbon and the other steel.

2) As any engineer will tell you, it's not about overall stiffness, it's about the stiffness to weight ratio. Compare a steel hard tail to a carbon hard tail OF THE SAME WEIGHT and then see what happens. 

When I worked at Specialized, they often had the same full suspension frame design, but with a carbon and aluminum version. They also had a multi million dollar MTS test lab in house. The design goal was to get the deflection numbers from the two frames to be as close as possible so they behaved in a similar fashion on the trails. This typically resulted in the alloy frame being 2-3 lbs heavier than the carbon version.

Carbon is so unique in how it can be tailored through the layup to give you exactly what you what from a design perspective, it is not really fair to compare it to tradition metal tube shapes that are limited to butting and hydro forming to change the characteristics. Carbon is only limited by the person designing it (and the budget). It can be much lighter, stiffer (where it needs to be) and more compliant (where it needs to be) than a steel frame ever can be.

But you can't braze a carbon frame together in the bong shed.....😉

This was surprising and definitely not the result I was expecting.

Great video, most interesting part for me was the deflection taken up by the shock (if I understood it correctly). Would love to see a continuation of this with a stumpy or something similarly notorious for eating shocks. 
No hate for the stumpy, really enjoyed mine while I had it.