Trek 2016: Trek brings IsoSpeed to the mountain bike

First seen on the Trek Domane classics road bike in 2012 and then on the Boone cyclocross bike in 2014, the IsoSpeed system isolates the seat tube from the top tube and seatstays, allowing it to flex back and forth to give some rider comfort. It’s still governed so that it doesn’t flex side to side and this motion removes much of the harsh buzz from the trail – especially on today’s XC race bikes with their treadless 1.9in tyres…

The IsoSpeed system decouples the seat tube from the shocks from the seatstay

Unlike the road version of the system, the seat tube is designed to work with seatposts and not the semi-integrated seat masts of road bikes (it also allows you to run a dropper post). The base of the seat tube is very tapered to help with that flex, too.

The ProCaliber SL comes in several specs, and a range of sizes. One thing about Trek’s Smart Wheel Size is that the 15.5in frame size gets 27.5in wheels, while everything larger gets 29in wheels.

Frame weight for a medium frame is 1,012g, about 100g heavier than the Superfly, but with a claimed 30% increase in vertical compliance over the Superfly. It’s designed to take a 100mm fork and both front and rear hubs are (as you might expect) based on the Boost system – with a 110mm fork and a 148mm rear hub.

Coming to the front of a race near you soon.

Pretty top of the shop spec there. No excuses now…

Chipps Chippendale

Singletrackworld's Editor At Large

With 23 years as Editor of Singletrack World Magazine, Chipps is the longest-running mountain bike magazine editor in the world. He started in the bike trade in 1990 and became a full time mountain bike journalist at the start of 1994. Over the last 30 years as a bike writer and photographer, he has seen mountain bike culture flourish, strengthen and diversify and bike technology go from rigid steel frames to fully suspended carbon fibre (and sometimes back to rigid steel as well.)

Comments (3)

ChippsChipps June 30, 2015 at 8:37 pm

It’s not isolated, it’s connected with a great big pivot.

slofoxslofox July 1, 2015 at 3:53 pm

I can’t see how it could flex much with that big connecting pivot!
I have a carbon seat-post on a full sus. and that is supposed to flex a bit. The way Trek have set this up can this seat tube move any more than that?

trekbikesuktrekbikesuk July 3, 2015 at 10:11 am

Hi all,

Just to clear up some things about the decoupler: If you removed the bushing and the two bearings there would be no physical connection between the top tube and the seat tube. This is what we mean when we say the seat tube is isolated. The IsoSpeed forms a mechanical connection between the two tubes. The effect comes from the flex of the seat tube, and that movement is in a region from just below the IsoSpeed, to around the first bottle cage bolt.

The action is clearly visible when you put an elbow on the saddle and push down, as you would to check the movement of a rear shock. When you measure how far the saddle moves from one end of the seat tube flex to the other, then you can see where this 11mm of movement number comes from.

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