Trust Message Fork Review, Geometry
At BikeCo.com we receive a lot of questions on suspension and bike setup. What works for who, how and why. With the launch of the carbon fiber Trust Message fork we’ve had many clients reach out. This blog is a Trust Message Fork Review concentrating on geometry and application.
As stated by Trust the Message fork rides unlike telescopic options. The Message utilizes an arced axle path from a pair of pivot arms with a leveraged air spring and damper. The differences in ride are somewhat hard to lay out after only a couple rides on the chassis. So rather than add to the “what I feel” category let’s look at factors in the wheel arc as well as the fork’s overall geometry.
Data from Trust Performance’s site:
535mm Axle to Crown
130mm of Contour Travel
From there we took measurements on the linkage pivots allowing us to create a CAD drawing of the Trust Message. While there weren’t datum table laser accurate measurements they are accurate enough to create a model that we could review comprehensively.
Trust Message Fork and Frame Geometry
The Message is marketed as an option to replace 110-150mm forks.
Based on the quality of travel – the leveraged design feels good by the way – it definitely feels like it has more travel (bottomless) than short travel forks. But, there’s feeling bigger and riding bigger…
Bike geometry is a finicky thing. Small changes make big differences. We’ve heard the arguments over headtube angle and bottom bracket height ad nauseam. Well, modifying the Axle to Crown measurement changes both of these dimensions.
Let’s look at some popular 29ers and how they shift with the Message installed in our CAD models. The data points below were generated from manufacturer geometry charts of bikes at full suspension extension.
Model Method: Wheelbase, chainstay, bottom bracket, axle to crown as well as headtube angle measurements were used to create a baseline. Frame models were rotated from the center of the rear wheel to accommodate for axle to crown differences while providing leeway for the wheelbase to change as required. Models were built to size large dimensions.
Yeti SB130 spec’d with a 150mm fork at 557.1 axle to crown, 44mm offset
The Yeti was at the bigger end of bikes for this exercise. The shorter Trust Message fork shifted the SB130’s geometry fairly notably.
Bottom Bracket dropped 7.7mm. Reach increased by 9.5mm. Stack dropped 16.8mm. Headtube angle was modified approximately 1.5 degrees.
These types of changes will notably modify a bike’s personality. That said, most people in the market for a bike like the SB130 probably aren’t looking for the advantages of the Trust fork either. It would be doubtful that either the fork or frame are done justice in combination due to the substantial shifts in geometry.
Evil Offering spec’d with a 140mm fork 551mm axle to crown, 51mm offset
If you’ve seen our marketing you are probably familiar with the Trust Message Evil Offering build. The Evil Offering is a great platform to pair with a Trust Message. The Offering was designed with a range of fork options as low as the 140mm option. Low and X-Low settings offer a variety of changes as well.
Our Offering model was build using the Low geometry settings.
With the Trust fork bottom bracket is lowered by 5.4mm, Reach increased by 7.3mm while Stack decreased 11.5mm.
The Offering is comfortable riding off the rear wheel which would help re-slack the headtube angle lost from the lower axle to crown.
Ibis Ripley LS spec’d with a 130mm fork 537mm axle to crown with 51mm offset
537 vs. 535mm isn’t much is it? Nope, especially when you factor that height difference is at a 67.5 degree headtube angle lowering the actual vertical measurement.
The Trust Message fork on the Ripley LS shifted the bottom bracket by less than a quarter of a millimeter. Given the measurement techniques (and margin of accuracy) we’re calling this geometry the same.
If I had to pick one of these bikes to trail test extensively I would gravitate to the Ripley LS. The Trust Message’s personality paired with the DW rear suspension on the Ibis could be an absolute blast for the right riding style.
Along with designing a leverage ratio as well as loading angles to work compensate for the air spring’s ramp the Trust Message’s contour travel takes advantage of other geometric changes for it’s riding personality.
Trust is quite forthright about their fork riding different. There are some notable reasons that it would.
The image below overlays a telescopic 130mm travel fork with the Trust Message. One of the things that surprised me was how close the axle positioning was between the two platforms. I had expected the contour travel’s arc to deviate further from the standard axle path.
The contour axle path creates variable offset (the perpendicular distance from the steering axis to the axle) as the suspension cycles. At full extension and compression the offset is greater than the standard fork while through the mid-stroke the offset crosses below the standard axis.
The telescopic fork in the model above features a 51mm offset at 130mm of travel. In the model the Truth Message offset measured 59.5mm at full extension, 42.8mm at 20% sag, 34.6mm at 55% sag and 58.3mm at compression.
Varying the offset also modifies the fork’s trail measurement.
Trail for Trails
Trail is a measurement between the intersection of the steering axis (extended from steerer tube) and a vertical dropped from the hub center to the ground.
Our CAD model showed nearly a 29% variation in the trail measurements with the Trust Message.
Increasing the trail setting in the “meat and potatoes” of the travel produces a different steering feel. In theory this would provide a more nimble steering feel outside of the 20 to say 75% sag range while in that range the steering would relax a bit.
It’s almost like slackening the headtube angle mid stroke. That is to say since trail measures a dropped vertical line from the axle with a static offset to increase trail we must slacken the steer axis.
The image above illustrates a 29% increase in trail from the far left to middle image through headtube angle change. Overlaid to the right you can see how substantial that change would be to a bike’s geometry.
Conclusion? Well, It’s Variable
So is the Trust Message the new be all and end all? Of course not. Not much is (although I did think 26’s would hang on a bit longer than they did…).
The Message should be a good option for bikes that can afford small geometry changes in the window of the axle to crown measurement from Trust.
Bikes like the Evil Offering and Ibis Ripley are interesting platforms to consider the Trust Message.
The Trust option tends to lend itself to riders with a quiver of bikes (it’s different and fun) or those looking for a “bigger feeling” fork on a smaller travel bike. Adding the “bigger” feel confidence can be a real game changer – look at what 2.6″ tires have done for traction!
Confused? I hope not, but it can happen… These are complex assemblies where small variations create large performance changes. Bikes at this level are certainly not “buy now” click purchases. Work with a quality resource to ensure you have a thorough understanding of what you’re looking at, how it’s going to be setup for you, and how you will develop with it.
Reach out to our expert staff to help you define the best spec for your riding style, aggression, ground speed, personality, aspiration and location. It all matters!
See you on the trails. Nate at BikeCo.com