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All-new Transition Spire 170mm 29er is the new enduro rig on the BC block

transition spire alloy full suspension mtb
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Hot on the tail of the mixed wheel Transition Patrol is an all-new enduro bike; the Transition Spire. The bigger, burlier sibling comes in carbon and aluminium flavors, running 29″ wheels and 170mm travel, front and rear. Those figures place it firmly in the enduro race bike category but Transition say this is far from a one trick pony. Here’s more.

Transition Spire

transition spire purple enduro mountain bike 29" wheels 170mm fork 170mm rear wheel travel

Building off the Sentinel is the all-new Transition Spire, their longest travel 29″ trail bike. Just like the new mixed wheel size Transition Patrol, the Spire geometry is subtly adjustable via use of a flip chip which dictates the position of the lower shock mount. 

transition spire
The Transition Spire runs a 170mm travel 44mm offset fork

In its lowest, slackest configuration, the Spire has the slackest head angle out of all Transition mountain bikes at 62.5°. That’s half a degree slacker than the TR11 downhill bike. That’s paired with a marvelously steep effective seat tube angle of 77.6° in size large.

transition spire 170mm travel enduro bike
All frames are compatible with 27.5 rear wheels in the high geo adjust position

Transition adjust that angle depending on frame size; it’s at its steepest on the small frame at 79.6° and its slackest on the XXL at 77.2°. That geometry will put the rider’s hips in a commanding position above the bottom bracket resulting in what should be a very pedal-able long travel bike.

transition spire geometry low setting

Switching the flip chip to the high setting steepens the head angle to 63°, while also steepening the effective seat tube angle by 0.5° across the board. It also raises the height of the bottom bracket by 7mm to 350mm.


With 165mm cranks (on every frame size), that should ensure decent ground clearance from pedal strikes. Though, it will of course depend on the amount of sag you run the rear shock at. Which brings me to…

Spire Leverage Curves

transition spire leverage curves

The Transition Spire varies in chainstay length dependent on frame size. The small, medium and large frames rock a 446mm chainstay while the stays of the larger frames are longer at 452mm.

transition spire leverage curves
Transition publish two leverage curves for the Spire, reflective of the two chainstay lengths


Its 170mm rear wheel travel is delivered, as ever, by Transition’s “Party Time” leverage curves, with a 23% overall progression said to provide enough bottom out control for use with both air and coil shocks, with a recommended sag range of 27-33%. Transition say that will allow the rider to tune the feel of the bike “from a firm and snappy jump and slash mode, to a more supple and active full on party mode”. That not progressive enough for you? Fear not, it’s likely Cascade Components are working on a more progressive aftermarket link for the Spire as you’re reading this.

Frame Details

transition spire orange
The aluminium Transition Spire in Orange

The Transition Spire is available in alloy and carbon framesets. The former is fabricated from 6061 aluminium. The latter is produced via Transition’s unique latex coated EPS molding process using a layup of 24T and 30T Japanese Toray carbon fibres.

transition spire alloy full suspension mtb huck

With the stock 205mm x 65mm stroke shock, the Transition Spire runs 170mm rear wheel travel. You can however drop that to 160mm by swapping the shock out for a shorter 60mm stroke. That configuration isn’t offered by Transition, however. It is merely an aftermarket alteration that Transition approve.

A boost spacing swingarm offers clearance for up to 2.6″ wide tires. For both the aluminium and carbon frames cable routing is guided internally for the dropper seat post and rear mech; the cable for the rear brake caliper is routed externally. 

The Transition Spire gets a threaded bottom bracket and a press-in headset, with the headtube approved for use with a dual crown fork. Its 56mm/56mm dimensions can accommodate reach and angle adjust headsets for those who want to slacken off the head angle even further without also making the seat tube slacker.

transition spire alloy

Inside the front triangle is an accessory mount and space for a water bottle. The frame is well protected with molded rubber panels on the driveside stays and the underside of the downtube.

Pricing & Availability

transition spire colors

We don’t have any specific details on availability just yet, only that Transition say bikes will be available “this summer”. They haven’t supplied us with model specs and pricing so you’ll have to head to their website for that. We can tell you that all models will feature four piston brakes with big rotors front and rear, Schwalbe Magic Mary and Big Betty Super Trail tires, 165mm cranks, a OneUp dropper post and a OneUp bash guard and chain guide.


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For all the cows
For all the cows
1 year ago

I wonder how many moons those frames weigh

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