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Pictures: Blissfield Images and Jackson Inexperienced
Many Pinkbike readers could have just a few, cracked, out of guarantee, or old-fashioned frames frames mendacity round. They now not have a use, however you bear in mind the nice instances you had and you’ll’t bear to throw them away. Effectively, how about turning them into one thing you really need?
I’ve constructed bicycle frames for a very long time. I began constructing frames utilizing metal so my companion and I might feed our tandem using dependancy. That is a good story too, however constructing frames that method is fairly gradual. As soon as I turned a dad and began constructing bikes for my children, I wished a approach to make frames extra rapidly.
More often than not constructing a body is spent mitering tubes and making small, uninteresting elements like chainstay yokes and bearing seats. Through the use of outdated frames, prepared made elements may be put straight into the jig to provide no matter geometry and suspension design is required. Moist layup carbon fibre, such as you would possibly use to construct a sailboat, permits these elements to be stitched along with sections of tube fashioned in-situ within the body jig – no mitering required.
Another bikes made with the identical course of. This one longer, decrease, slacker…
And this one shrunk from a dimension giant to a 20″, together with shrinking the fork!
Design Course of
The Pinkbike remark part is stuffed with folks with opinions on mountain bike geometry and suspension design. By making my very own bike, I get to place my concepts in to follow.
Generalized Mountain Bike
Body: Horst hyperlink, carbon entrance triangle, carbon/aluminum rear triangle, 170mm journey
Shock: Rockshox Tremendous Deluxe Coil Final, 205x65mm, 450lb/in spring
Fork: Rockshox ZEB choose with Charger 3 damper, 170mm, 56psi, 0 tokens
Wheels: Mullet
Tires: Maxxis Assegai entrance / Minion DHF rear
Drivetrain: Shimano Deore wide selection 11 velocity with Sram NX crankset and SUNSHINE 11/50 cassette
Brakes: TRP DH Evo, Hope 225mm entrance rotor, TRP 203 rear rotor
Cockpit: 25mm rise Spank Vibrocore 35 bars with 40mm Spank Break up 35 stem
Dimension: It suits me properly
Weight: 17.0 kg (37.5 lb) as pictured
Building Particulars
The body is made primarily utilizing the remnants of a cracked 2017 Large Reign Superior lower into many items. The BB shell, chainstays and chainstay pivots had been modified from an aluminium Stumpjumper circa 2005. Lastly, the rocker from a 2019 Reign, which had been cracked however solely wanted to be repaired, not modified.
All of the essential factors had been held in place in a body jig. My jig makes use of a base of 100×100 sq. hole part because the reference for horizontal and vertical. Fixtures are then clamped to the bottom utilizing woodworking clamps. Most of my jig fixtures are created from easy metal plates with axles and cones to carry the body elements, however the headtube and seattube fixtures use extruded aluminum sections for added stiffness.
As soon as the essential factors had been all jigged up, varieties for brand new tube sections had been made utilizing florists’ foam and held in place with sizzling glue. The items had been then joined utilizing moist layup carbon fiber wrapped immediately across the body items and foam. After a primary layer to supply sufficient energy for dealing with, the body was de-jigged and a second layup was carried out to attain the specified composite thickness and energy. Every layup was wrapped in peel ply or insulation tape to compress the laminate and squeeze out extra resin. The tape was eliminated earlier than the resin was totally cured.
After a little bit of trimming the bike was structurally completed so I used to be in a position to take it for a check trip. As soon as it was confirmed that all the pieces labored the way in which I wished, I stripped the body for ending and portray.
Within the jig with a lot of the elements already tacked collectively.
Guaranteeing sufficient chainring/chainstay/tire clearance is without doubt one of the hardest elements of a body construct.
The bike makes use of a regular rocker hyperlink from a 2019 Large Reign. This one simply needed to be bolstered as a result of it was cracked.
The insulation tape composite compression methodology works properly however leaves a poor end that wants a whole lot of fill. Does anybody else suppose it seems to be like toothpaste?
How does it trip?
The Mountain Bike’s middle-of-the-road geometry offers a really acquainted really feel proper from the primary trip. It’s an all-rounder with no excellent strengths and no obvious weaknesses.
Whereas climbing, the cockpit feels brief however not cramped, with a relaxed, upright using place. The reasonably lengthy chainstays assist to maintain weight on the entrance wheel and keep away from extreme imprecise emotions whereas cornering on much less steep terrain. The antisquat hovers round 100% giving a impartial really feel with loads of grip, and no want to succeed in for the climb change. With 170mm of journey and burly tires, the Mountain Bike does not have the pep of a cross nation race machine, nevertheless it climbs properly for a motorbike on this class and could be very comfy tackling all day epics with elevation measured within the 1000’s of metres.
The Mountain Bike additionally delivers no surprises whereas descending. It is attain and chainstay size centre the rider on the bike, serving to to weight the entrance wheel and giving a confidence-inspiring feeling whereas cornering. The reasonably progressive suspension design combines properly with the Tremendous Deluxe Coil’s hydraulic backside out to supply a predictable and supportive platform. It’s fairly delicate off the highest with good traction, however has sufficient midstroke assist to supply a platform for leaping and pumping. On rougher floor and thru g-outs it rides excessive sufficient in its journey to maintain one thing in reserve for greater hits.
Alternatively, the rear finish is on the versatile facet for a motorbike on this class. Whereas this flex feels nice on pure terrain however generally is a bit imprecise in excessive g-force bike-park terrain. That trait fits me nice as I’ve a DH bike for the park, however had I wished to make the rear finish stiffer I might have added additional carbon fibre to the chain and seat stays, or have sourced the chainstays from one thing extra burly than an 18 yr outdated Stumpjumper.
Nonetheless understanding the best handlebar peak.
The donor bike for the underside bracket did not have chainguide tabs so I went for direct mount chainguide as a substitute.
It would not damage to discover a longer shock bolt.
Constructing a customized body this manner actually will not be for everybody. Not like building utilizing metal, there are few guidelines of thumb or established practices to make sure the body shall be robust sufficient. As an alternative, the framebuilder has to determine for themselves how a lot carbon fibre material so as to add, what weight and weave to make use of, and at what orientation. A conservative method is required to make sure the result’s secure. Nonetheless, for an skilled builder it delivers good ends in little time. It’s also very satisfying to have the ability to creatively re-use frames that may in any other case go to landfill.
Experience Protected
Jackson Inexperienced
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