The Tractor: part beauty, much more beast. One of the most stunning and best-performing bikes I ever threw my leg over.
I didn’t plan for it to become ‘The Tractor,’ it evolved. I wanted rusty and raw, but that’s not allowed. So I guessed at the green powder coat from the standard colours offered by Starling, then yellow decals to match the Ohlins Suspension.
Starling Spur - The Good
The Tractor: part beauty, much more beast. One of the most stunning and best-performing bikes I ever threw my leg over.
I live on a farm, which cost little more than double the total spent on this bike review. When the Spur was assembled it became an agricultural beast made of straight steel, carved alloy chunks and steel pinions meshing together. It looked perfectly at home next to a freshly bailed hay wheel and was named suitably.
Unfortunately, the Spur never got its pair of yellow wheels to upgrade it to John “Nothing Runs Like a Deere” specification, they’re still hanging up in the garage. The rest of the story will follow, but for today, we will focus on The Good.
I ordered the Spur at the end of 2021 and took advantage of buying from a small British builder and slightly customised the geometry with a 520mm reach and 62º head angle, the rest of the geometry is standard fair for an XL Spur. The other interesting numbers are a decent length 450mm chainstay, 77º seat angle, and 38mm of bottom bracket drop.
The frame is Reynolds 853 steel which carries a 9-speed Effigear box from France. The single pivot swingarm rotates around the box itself and the output drive shaft. This means the chain line is a single-speed setup, tensioned via asymmetric dropouts inserts, and no flappy or noisy tensioners in sight.
Other details include plenty of gussets, some with laser-cut Starlings, the swingarm bolted together with an X-plate and the all-important water-bottle mount under the top tube. The other specs are all sensible steel with a straight 44mm headtube with external cups, 31.6mm seat post with integrated clamp, and 142mm rear hub spacing with an IS-standard brake mount, so you can bolt any size post-mount adaptor you like to it.
After building up the bike and heading towards the trail there are plenty of positives to pay attention to. The gearbox was, er, tractor-like to start with, a rumbling agricultural feel. But, it bedded in and smoothed out after the first couple of rides and 50km. The Effigear offers the best up-changes I’ve ever felt in any system: put the power down and click into a harder gear sprinting like hell and it changes instantly under full power, so quickly and smoothly that sometimes you’re not sure if it changed. The Effi system uses a standard SRAM trigger shifter so no need to worry about gripshift, even though I personally don’t struggle with that too much on Pinion systems.
Up or down gears can be changed as much as you like at any time when coasting or stationary – which is amazing when you get used to it – a normal derailleur cannot change at all under these conditions which take up a large portion of time on the bike and stopping and starting. This can be used to gain an advantage over a derailleur.
When paying attention to the speed and selected gear I often found myself shifting gears way before I needed to pedal. Heading towards tight corners, for example, I could click a few gears and know I’d be able to pedal out of the corner at a nice cadence. This also becomes habitual in more simple scenarios like changing a couple of gears before dropping into the trail after a slow and steep 1st gear climb, your mates might be standing next to the bike holding the rear wheel in the air and hand cranking the pedals to find the right gear before going downhill.
Changing down into easier gears with the Effigear is a different story. I don’t think it is necessarily bad, but it is definitely different. You need to stop pedalling for a short split-second to allow the gear to shift. If you pedal continuously and click into an easier gear, nothing will happen until you stop pedalling, then it will instantly shift. This can suck when climbing on steeper grades as you will lose some momentum. But, with some practice can also be improved to time shifting at the 12/6 ’o’clock position when you are putting down the least power through the pedal stroke. It can work well on techy climbs if you see a suitable pause coming up, maybe a small step, you can click the gear first and then wait for the pause to change. With a normal derailleur, you have the advantage that you can shift under some load on steep climbs, these shifts take more time whereas the Effi shifts instantly when you stop pedalling.
I think that a big problem with people’s opinions about gearbox bikes and difficulties changing gears is mostly down to lack of habit. Riders and testers forget they have spent years or decades learning to change gear with a derailleur and are now very used to it. If you teach a beginner to ride you’ll be reminded there’s a lot to learn with derailleurs: timing the change and cadence, reducing power at the right time as the chain changes sprocket, and the difficulty of changing multiple gears at the same time. Sometimes you end up in a situation where you might need to lift the bike and spin the cranks to change 4-5 gears. With the Effi (and Pinion) gearboxes there are differences that are seen as a disadvantage to start with, but over time you can learn to work around and with these problems and find more benefits, in the same way that years of derailleur practice helped with.
The pedalling position on this bike is great, nice and upright with great resistance against front wheel wander and wheelie thanks to the long CS, steep seat angle and long front end: this thing really can crawl at tractor-like speeds up anything.
Suspension support when pedalling is great from the linear suspension and well-damped coil shock despite running a plentiful 30% sag. There’s the lockout lever option to reach for on the shock head but I rarely used this as there was no pedal bob for me at all.
There’s no chain tension on the drivetrain to create anti-squat, the suspension support solves this most of the time under smooth power on roads or trail. But when putting down more aggressive pedal power and more weight through the saddle over dips, bumps and steps, the bike doesn’t pull you up and over obstacles, like say, a GeoMetron G1 will. Those bikes with higher AS values keep the back of the bike riding higher when powering up and over where the Spur will sink in to the travel more. But, this ain’t no XC pedaller, it’s a DH bomber.
The drivetrain definitely has enough range to get you anywhere. But it is ideally suited to alpine and lift-accessed terrain: bomb down a rocky black run without a care in the world for the flappy derailleur. Jump back on the lift. Spot a ridge with that secret descent in the distance. Spend half an hour gently on the pedals to get to the good stuff. Commence care-free bombing again, and again.
Along, then Down
When the Spur is up to rolling speed it comes alive. Despite a weight of around 19kg, this bike rode incredibly lightly. This is something I’ve found with all of the more linear bikes I have been testing this year compared to more progressive setups. The linear ratio gives loads of mid-stroke support making the bike feel light and agile responding quickly when you push against it.
It pumps and pops really well. The heavy central mass can be used to your advantage to generate pop with comparably light wheels. It has a more than comfortable central riding position and carves corners perfectly. A more centralised position is much easier to ride and safer to control than an out of balance bike claiming a ‘long front-end for stability and super-short rear for snappy cornering.’
As things speed up and gradients and impacts increase, silence is bliss. The perfectly tensioned single-speed chain setup with a lack of any derailleur or chain tensioners makes this Spur incredibly silent, only the noise of rubber gripping and the oil damping can be heard. No chain flap ever and those slender steel tubes don’t amplify any noise like bigger box sections.
This bike has most of the weight centred in the mainframe and boasts a very light rear wheel. This setup with no cassette, no extra wide hub, no lanky 12speed derailleur and no chain tension means the rear wheel moves out the way of everything, and I mean everything. The rear suspension has a suppleness and response that is not matched by any other bike I’ve had on test. I believe this is an extra benefit for flat pedal riders like myself as with no tension on the chain yanking at the pedals while you are hitting the rough stuff means your feet will stay planted much more than a normal bike.
People will say this bike is heavy, but there’s nothing like the ride quality of this Spur and its huge weight distribution advantages over the majority of bikes. Many current bikes now have a very lightweight mainframe with a heavyweight drivetrain and big wheels which will lose to the Spur massively in the sprung-to-unsprung mass department. Ask any suspension engineer about performance I’m sure they will confirm the sprung/unsprung mass ratio is much more important than overall weight.
That slender swingarm, steel, single pivot and sensible hub spacing means something else: grip. F-ing S-loads of grip, like nothing else. It’s not a super stiff frame for road sprints, but it is stiffer than it looks and plenty firm enough for off-road riding through roots and rocks and along cambers. Single pivot means low friction through minimalist bearing rotation. The steel just gives in a way that alloy and carbon can’t, it only flexes in a controlled manner, there’s no load-up of force in an overly stiff and hard swingarm followed by that energy release and springy feel found on many other bikes.
The sensible 142mm Hope S/S hub means symmetrical spoke flange spacing connected via butted DT-spokes to the narrow EX471 rims. This allows nice and low, but also equal spoke tensions, something lacking massively on modern MTB: I’m not sure how we ended up with so many versions of hubs and still nobody could design something symmetrical, the No.1 factor that every expert wheel designer or builder really wants. Even modern Boost front hubs don’t have symmetrical spoke spacing.
This narrow rear hub design and lack of danglies from the rear axle means you can get closer to the edge of the trail than ever before, and plough through rock gardens without a care in the world.
Some people might shout “brake jack” or some other complaint about single-pivot bikes under braking. This bike is another that proves that problem wrong. Some anti-rise plus the super stable geometry combined with a supportive fork and high bar says goodbye to this. A more stable mainframe means you can brake more on the front and less on the rear, this means more slowing down and less skidding and harshness. On top of this, the lack of pedal kickback, the grippy setup and superbly supple suspension means the bike just sticks to the ground when braking on any surface – impressive.
“But won’t it bottom out instantly with such low progression?” I bottomed this bike out a couple of times. After lots and lots of testing with other bikes this year we discovered that bottom-out resistance can actually be higher on a linear bike – providing you have the correct spring rate and a suitable amount of damping which many stock shocks don’t have. I find with a well setup and more linear bike, there is enough support from the damping to prevent bottom-out in all normal riding situations. A linear bike is more predictable and it’s easier to know when a full travel event is coming, brace with your body and let the bottom-out bumper do its thing.
All in all, the Spur is one of the best descenders I ever used and could have possibly been the best with some more tweaking and tuning. Unfortunately, I didn’t get to do much more riding on this than the initial shakedown rides and tweaks. But, starting with well-tuned suspension via J-Tech, the custom build using parts I’m already familiar with and spacious and safe geometry, the Spur was very easy to get to grips with. I could ride at my best in any situation after a couple of runs.
Then things started going sour. The next articles detail The Bad and The Ugly.
You can win this bike on my site and support independent bike reviews and the only guy calling out the big players for bad moves. The Spur problems have now all been solved and I’m confident it will provide a lucky winner with one of the best-performing mountain bikes ever made. A big part of me wishes I could pick The Tractor back up and enjoy it back at its true home, The Bike Farm. But, my enjoyment has to be given away to someone else as AstonMTB needs to keep moving forwards and striving to #buildbikebetter.
Win the Starling Spur here! You can also check out the Introduction and Build Videos on my Youtube Channel here.