2021 Trek Session: The High Pivot, Idler Pulley, Fast And Fun Machine

Right, get comfy, we have much to talk about. The new 2021 Trek Session is very different, and yet very familiar. Firstly, do we call it a downhill bike? A freeride bike? The Session has great history and has succeeded in many places – notably Rachel Atherton’s ‘Perfect Season’ and at Red Bull Rampage, under Semenuk and Rheeder. This new 2021 Session, though, has much in common with the Session from 2006, and the 2003 Diesel before that. Why’s that then?

Idler Pulley

That’s the biggest visual change to differentiate the 2021 Trek Session from the 2018 model. There’s a carefully positioned high pivot on the frame, with an idler pulley to isolate the drivetrain from pedalling forces. As mentioned, the ‘single pivot with idler’ idea first appeared on the Trek Diesel way back in 2003, before the first Session appeared in 2005. Then in 2006, the Session 10 incorporated an idler pulley too. Later Sessions moved away from this, with Trek’s ABP system being adopted, as well as carbon frames in 2011. That’s another thing that the new session has in common with its older siblings: the frame material.

Trek claims the High Pivot offers a smoother, plusher ride and better square-edge bump resistance, as the wheel is moving more backwards than just upwards. This should help it carry speed better. The idler pulley allows for much less pedal ‘kickback’, where the pedals are jolted backwards on hitting bumps, thanks to the suspension pulling on the chain. The previous model moved the pedals 15-27° through the suspension range, where the new 2021 model’s pedals are only affected around 5-8°.

Aluminium frame

In a surprise move, Trek has gone with aluminium frames throughout the range of the 2021 Session. This was a surprise to Trek’s engineers too. What happened was that several alloy ‘mules’ were welded up to get the frame dimensions right and to test the suspension. It turns out the team riders like World Champion Reece Wilson said they preferred the ride of the alloy framed prototypes (presumably over similar carbon prototypes, though that wasn’t clear). The bike has certainly been in development long enough to have made a carbon frame if Trek had wanted to. The initial test sessions were right after the end of the 2019 DH season – Trek rented a whole downhill park in New Jersey to test the prototypes in secret.

Suspension Mino-Link

Trek’s Mini Link has appeared before, but it’s usually to adjust a bike’s angles. This time, the link at the bottom of the shock mount adjusts the shock’s progression. There’s a 25% option for smoother trails and a 20% option for the rough stuff.

Sizing

Trek has joined a few other companies in doing away with height-specific sizing. There will be three ‘sizes’ of the new Session, measured by their reach measurements: R1 has a reach of 440mm, R2 is 465mm and R3 is 495mm. Overall, the reach measurements have increased by nearly 10% on previous models. The standover height is the same across all three sizes. However, shorter riders will be disappointed that the equivalent ‘small’ frame has gone away.

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Size specific chainstays

Geometry hounds will be pleased to hear that the three sizes of bikes will features three different chainstay lengths too, to balance out that increasing reach. These are: R1 – 439mm, R2 – 445mm and R3 – 452mm.

Mullets? If you want!

As you might expect these days, some riders are after a mullet setup, with 29in up front and 27.5in at the rear. That’s entirely possible, as is a full 29 and a full 27.5in rig. This happens thanks to a second ‘Mino Link’ on the seatstays. This isn’t to adjust geometry, but to allow for different wheel sizes. So, the bike comes stock as a 29er, but if you run the Mino Link in High, then your Session becomes Mullet-friendly. If you want to run a full 27.5in wheel setup, then add the optional EXT Headset cup and run the link in High again for full 27.5in compatibility.

Other cool stuff.

That’s nearly the whole bike, but what else is there on the Trek 2021 Session? There’s bolt-on and extended downtube armour for starters, there’s a moulded, dual density (and replaceable) rubber chainstay guard and there’s also cable routing options. You can run the cables through the top tube for neatness – but if you’re likely to need to swap your brakes over a race weekend, for example, then there are also external cable guides so you don’t need to pull hoses through frames.

For 2021, there will be two complete versions of the 2021 Trek Session – the Session 9 and the Session 8.

The Session 9 features a Boxxer Ultimate, Rockshox SuperDeluxe Air, SRAM X01 transmission and Code RSC brakes along with Bontrager Line DH wheels.

The Session 8 will have a RockShox Boxxer Select+, a Fox Van Coil, SRAM GX DH drivetrain and Code R brakes.

There will also be a Trek Session frameset too. This will come with the Fox Van Coil shock and will include the EXT headset cup so you can run it with whatever wheels you want.

Prices?

• Trek Session 9: £6300
• Trek Session 8: £4500
• Trek Session Frame: £2750 (includes shock and EXT headset cup)

Knowing Trek, the bike will be shipping to dealers this week, so if you’re interested, then don’t delay…

See more of the new 2021 Trek Session at Trek’s Website.