Starling Cycles Releases the Sturn V2, a Steel, High-Pivot Singlespeed DH Bike
Starling Cycles announced today that it has updated its Sturn downhill bike, which was originally released in 2018 and has been modernized with a new swingarm and a refined Jack Drive system.
The Jack Drive is what you'll likely notice about this wild-looking bike, and you may recognize it from the Brooklyn Machine Works designs that inspired it. The system runs the suspension and drivetrain through the same high main pivot to eliminate the problem of chain growth, which Starling says creates less friction than using an idler pulley. Also, yes, that means you can't technically go wrong when photographing the bike, as both sides are the drive side.
Starling Cycles founder Joe McEwan began making bikes in Bristol, UK, in 2014, and most Starlings are still handmade to order at the small brand's headquarters.
The Sturn comes with custom sizing and geometry. Starling will make you a multi-geared version if you ask nicely, similar to this five-speed prototype from 2018. However, Starling stands behind the singlespeed version for its simplicity, dialed chain line, and minimal rear wheel weight.
While the Sturn V1 was a 29er, the Sturn V2 is available for 29", 27", and mixed wheel setups. It has 200mm of rear travel and is built for a 200mm fork, has an adjustable shock mount to fit multiple shock sizes and allow for geometry fine-tuning, and uses Starling's own dropout system, which lets users remove and replace the rear wheel without having to readjust chain tension.
The Sturn is designed for 142x12 singlespeed rear hubs, fits up to 2.8" tires, and has clearance for 200mm rotors. Like Starling's other bikes, it's available either as a frame alone, a frame and shock, or a complete bike built.
Pricing starts at £2990 for a frame. Learn more at starlingcycles.com.
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157 Comments
As a Canuck it's cheaper for me to buy American now...
Chances of it being lies when a politician speaks? 99% of the time
"Gosh, nothing is quite like a Starling. Look at the steel, the craftsmanship, the high single pivot!"
*glances to scan a sea of similar production bikes*
"That Orange on the other hand is a slight against humanity."
Here's a basic lesson in geometry - once the inner angle at the shock to swingarm mount goes from an acute one, and past 90 degrees, into an obtuse angle, you're into a falling rate. And falling rate rear ends are f****d - well, dreadful , to use gentler language.
They are having to do an extension on the lower swingarm / chainstays to get past the seatpost to their existing pivot point, so making that extension longer is not going to be hard for them. Put the pivot point further forward, bring the shock to swingarm mount back closer to the seatpost, and bring the frame mount down lower to make it so they don't go past 90 degrees, and into falling rate, with Any length and travel shock that might be fitted .
I'm sure I've commented on this companies falling rate fetish, before.
It just ruins Single Pivot performance. They and their customers will says it's great, but, no, it's not.
The only way for that frame, to be Not going into falling rate, as it stands with that Swingarm and Main Pivot point, is with use of a far shorter - length and travel - shock, with the front shock mount further down, using that myriad of what may be other shock mount holes.
As to the jack shaft - well, it's been done before, and will be done ever and anon. I'm fine with it, but it's a Lot of added complication - but, it is for a Valid purpose. They can have a RH drop out to take a Derailleur mount, if anyone wants gears. They'd still have the advantage of the constant swingarm pivot to axle length, which would give a derailleur a far, Far easier time than so many other rear ends. A single speed? - not my cup of tea, as Poms would say, but, go ahead, run what you want. I'm for at least a few gears, for more versatility than a single speed allows you, and, for easing up on (further) knee destruction, and, at my age, less chance of a heart attack............
Yes, I'm opinionated on this, but I've been making my own Single Pivot bikes for nearly 5 decades now, and there's no way I'd make a rear end with a falling rate - I made that sort of mistake in my early teens, and, learned from it. I wish I could post a picture here - I'm an Actual Frame Maker, not an amateur engineer or "internet expert". I've got an example of one of my frames I could show, having it's final build up, right now.
Good rant there!!
Take a second to look at the leverage ratio curve but with the full axis; 0-3.0, not the zoomed in version that Linkage shows. What you'll see is that the leverage ratio to all intents and purposes in linear. Yes, it may go everso slightly negative towards the end, but there's a good engineering term for use here, "two tenths of f*ck all".
A linear ratio, with a big rubber bumper on the shock (or an air shock that ramps up), works really well. Multiple race wins, National Champion, loads of very happy magazine reviews and customers!! Perhaps they are all wrong?
As much as people like to think so; bikes aren't designed by a bunch of numbers. It the sum of parts that matters, and in this case the sum of parts rips!!
It's not hard for them ( You? ) to rectify this, but, I see with all of the frames of theirs, that they seem to be wed to Sway Back, Falling rate rear ends. Better with an air shock, or, use a multi rate spring? Well, the ramp up of an air spring might help, and the closing of coils might into a heavier rate might do so, too, but you've still the damping that's being subjected to falling rate. Yes, with a positional damper design, you might correct it, but, why rely on that , instead of building something that doesn't need such a 'cure' for bad design?
Looks like the chain may be damned close to sawing into the swingarm, with that humpback/ non straight jointing at the oval chainstay / cross tube / front plate junction. I can't see why that would not be made to be a non humped weldment. I'd like to see a picture from the RH side. The video shows the chain may be directly against the rubber buffer, from the get go, and, of course, with a concentric pivot point, the chain won't be 'lifting' from the swingarm, at all through the travel.
Yep, this is a proto, production bikes have straight (vertically) chainstay.
I kinda suspect you're trolling, so have fun with the rest of your life!! I'll get my satisfaction from building great riding bikes. You can get yours by ranting on the internet!!
Why not acknowledge what the guy is saying and not be rude by dismissing him when he is going out of his way trying to help you. Everyone here is interested in the finer points of suspension design and performance and your inability to engage in a technical conversation is not helping sell your product.
I would take a wild guess that he isnt going to learn much from someone that decides by looking at a photo of his bike that the suspension is going to be 'f*cked' or 'dreadful' - the 'finer points' are not being discussed at all.
slightly arrogant of him saying all starlings customers are wrong in saying their bikes handle well when “they actually ride f*cked “. I seem to remember an early starling being the fastest bike on dirt magazines 1min 30sec mini dh run/trail. Beating some very established names in the process. So I would imagine they handle ok.
Did he mention race wins and a national championship!!
I wouldn't call criticising falling rate (or even linear) suspension an "obsession"... or even much of an opinion for that matter. More like stating facts. There is a reason current designs avoid that. Or do any of you here who downvote @Bearorso to below threshold (lol typical PB) genuinely think that's the way to go?
Fuzzy marketing speak like "it's not black and white", "our bikes ride great" is far from discussing finer points.
Starling bikes are beautiful and that they're made down the road is a cherry on top because supporting local business and avoiding the whole multi-thousand mile shipping footprint would make me feel nice and warm inside. I was in the market (just ordered a different bike) and Murmur would have been top of the list if it had a different suspension layout.
Calling something ‘f*cked’, dreadful and implying customers are too stupid / duped to see the truth and will say they ‘like it anyway’ isn’t a discussion of ‘the finer points’ and I think isn’t far away from trolling.
Anyway, over to you with a kinematic analysis of the Starling suspension system and why it is worse than any single pivot with a linkage.
Loved your work back then and I'd be super keen to see what you are working on now.
I'm also a big fan of Starling's work too though. I have a Starling Twist and I love it. It rides amazing with an Ohlins coil. Pedals great, doesn't blow through travel.
Yeah, falling rate is not ideal but I remember I ran the Twist through linkage and I don't think it actually get's into that falling rate zone you are talking about. It's pretty well linear. Really nice anti squat and anti rise numbers too.
Not sure about the Sturn. I'll have to model that later.
Also, Joe from Starling is an actual engineer and frame maker. You'd probably get along really well!
1.
ignoring the true complexities of an issue; superficial.
"facile generalizations"
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oversimplified
schematic
black and white
shallow
pat
glib
slick
jejune
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thorough
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2.
(especially of success in sport) easily achieved; effortless.
"a facile seven-lengths victory"
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effortless
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@jaame: Poor bastard, unless the joke was particularly horrendous (as in absolutely odd the scale racist for example) that’s just nuts.
@willf28 @hhaaiirryy : I don't have a bike right now to verify... But I'd say on the drive side, the pedal is screwed "normally" (clockwise).
When you pedal, right crank viewed from the right goes clockwise, the pedal stays level... So it should tend to unscrew?
If ChOu177 & I are mistaken, please explain
So you’re right, if there was no bearing in the pedal it would spin out. But the dominant force that tightens the threads is a from ‘thread precession’ which arises from the clearance between the male and female threads, the inner threads roll around inside the outer s and this causes the pedal to tighten.
To install a pedal you have to turn tour crank backward so logically when you pedal it loosen it.
Very tidy, Starling
Wondering what the two mounts on the underside of the top tube are for?
He may have a good idea with this one, kinda like hammerschmidt but built into the frame/suspension system.
I had a "single speed" bike with a Hammerschmidt.
It was nice, but the Hammerschmidt is unfortunately as heavy as an usual 1x transmission.
The only benefit was that it required less maintenance.
Explain this to me like I'm a 5 year old please?
Everyone loves playing at DH. Not everyone has the time or inclination to Race.
Ive always thought it would be a great "sub niche"
www.starlingcycles.com/why-our-steel-seat-stays-are-strong
"To summarise. Steel IS STRONG! My thin seat stays are plenty strong enough and the compliance they give results in the great ride feel and grip of my bikes."
So although they're strong.. are they stiff? we all know that steel manufactuerers like to use "compliance" as an excuse for these stays are so flexi it might as well be steering with the rear.
That said tho I would love a rag on this sled.
And even though I don't mind bro-sciencing away with you in the comment section, at the end of the day someone is going to test these bikes and see whether they're actually too flexy or just fine. And as said before, maybe more lateral flex could actually be good when cornering rough flat or off-camber turns as this is what you need for the rear wheel to keep track.
I'm not denying any claims an I've had eough good, stiff steel bikes (an a good decade of street BMX) to be a chromo fan boi (my dream bike is a quiver of BTR's) but, I've also had a couple that could be stiffer And after my experience with a certain steel bike from a UK company with a good rep, marketing a frame as stiff enough for 4X being a total wet fish,
I'll need to ride a bike myself to see....
I love what Joe's doing and I love seeing a business like this local to me. But Starling sticks to a frame and suspension design that has certain inherent traits which not everyone will like (that's not to say some won't). Flex is one thing, that non-linkage single pivot is another.
Starling: Yes!
Love it.
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