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24" stock with a rear disc (6.97 kg)

5 posts in this topic

Nowadays, 20" bikes usually have disc rear brakes, and 26" bikes have rim rear brakes.
So what is the best type of a rear brake for a 24" trials bike, rim or disc? There was only one way to find out...

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About rear disc brake:

(I have been riding rear rim brake on 24" since 2008, so I compare mostly with the rim brake setup)

Disc brakes are standard for 24" in street trials, but pure trials is a very different thing.

When it comes to disc brakes in trials, one of the first things that comes to mind is the flex between rim and rotor. It feels terrible if the flex is significant.
I tried to make the flex as little as possible: stronger spokes, maximal spoke tension, hub where disc mount connects directly to the flange, strong symmetric rotor, no adapters.

The result is pretty satisfying. There is some flex, but not much, about a few mm. The tyre deformation feels much more significant than that much of a flex. 

A real advantage of this setup is much more controllable breaking than with the rim brake, that does really affect riding, and in a good way.

The hold is a bit better with a disc than on my previous rim setup. I also like that hold doesn't get worse in dusty/wet conditions, which was the issue with the rim brake.

Not sure yet which setup I like more, disc or rim. But at least disc setup seems to be a working option for me, not just an experiment.


About the frame:

1075 mm - it's really long for a 24" bike, 20 mm longer than my previous Echo 24". Gaps and pedal ups are easier on the new frame, but switches have become much more difficult.

There are a lot of situations in trials when you carry the bike by the top tube. It's much more comfortable to hold the top tube without the hose outside. That's why internal routing was a must. So I had to cut hose holders from the frame, and put some stickers on the place.




Spec:

Frame and fork
- Frame: Gu 24" 2019 (made internal hose routing, cut some holes on the bottom bracket tube to reduce weight) 
- Fork: Rockman Carbon 24" 4-bolt

Front wheel
-
Rim: Neon Single 35 mm
- Tyre: Schwalbe Rocket Ron 24"х2.1
- Tube: Schwalbe 7C
- Hub: Verzin SL 
- Spokes: Sapim Laser 2.0-1.5-2.0
- Nipples: DT Alu

Rear wheel
- Rim: Neon Single 47 mm
- Tyre: Schwalbe Fat Albert Rear 24"х2.4
- Tube: Schwalbe 7C
- Hub: Jitsie Race 135 disc
- Spokes: Sapim Race 2.0-1.8-2.0
- Nipples: DT Alu

Front brake
- Lever: Trialtech Jack Carthy
- Slave cylinders: Echo TR
- Pads: TNN Belaey with Racing Line alu backings
- Racing Line alu fittings and grub screws 
- Clamps: Echo TR with Ti bolts

Rear brake
- Brake: Hope Trial Zone
- Pads: Jitsie
- Rotor: Hope V2 180 mm

Drivetrain
- Cranks: Born CNC 2012 162 mm
- Freewheel: Jitsie 108.9
- Bashring: Trialtech Sport Lite
- Chain: KMC X9-73
- Rear Sprocket: Jitsie Alu 14T
- Pedals: Trialtech Jack Carthy
- Bottom bracket: Echo Urban Ti
- BB bolts: Ti M15

Steering
- Stem: Neon Wing 150х30 with Ti-bolts
- Grips: Pro bar tape
- Handlebar: Clean Carbon K1.2 690 mm
- Headset: Echo tapered


Weight: 6.97 kg


Geometry:
Wheelbase: 1075 mm
Chainstay length: 368 mm
BB rise: 75 mm
Head angle: 73°


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very impressive! 

im a bit blown away by how light this thing is!

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Very nice build as always.

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I'm in love with this build! The attention to detail is fantastic! :wub:

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