AUTHOR Ultrasonic 27,5 2021 - tripple butted alloy frame

Ultralight junior racing special on 27.5 inch wheels. If you are looking for the best in given category for your rider, this is the right choice! Very light alloy frame made of triple butted tubes, shaped by hydroforming technology, which guarantees strong and very durable process with minimal weight. RST air fork, SHIMANO Deore components, 11 speeds, TEKTRO hydraulic disc brakes with excellent braking performance. A machine that will definitely not be bored on the race route, but will also be a perfect buddy on any trip!

other models

Interested in other model`s year?

2019 2020 2021

Technical specification

Size	14", 16"
Frame	triple butted hydroformed alloy 6061 27.5"
Front fork	RST F1RST 27.5 air, lock out (80 mm)
Head parts	AUTHOR Integrated 1.5" tapered
Chain Wheel	PROWHEEL 32 teeth 165 / 170 mm cranks
BBParts	PROWHEL BB unit
Rear derailleur	SHIMANO SLX
Shifters	SHIMANO SLX (11)
Free wheel	SHIMANO M5100-11 11-51 (11)
Chain	KMC X11
Hubs	AUTHOR Xenon 32 holes
Brakes	TEKTRO Gemini disc hydraulic (6" rotors)
Brakes levers	TEKTRO Gemini WS

Rims	AUTHOR Xenon TRC 27.5 32 holes
Spokes	black stainless steel 2.0 mm
Tires	CST B-Trail aramid 27.5" × 2.25"
Pedals	alloy
Handlebar	AUTHOR Flat Top bar 9° 620 / 640 mm
Grips	AUTHOR kratton rubber
Stem	AUTHOR alloy
Seat post	AUTHOR alloy (31.6)
Seat clamp	AUTHOR (34.9)
Saddle	AUTHOR Champion Author Navigator
Speed	11
Weight	11,5 kg / 16"

Geometry and sizes

Size	14"	16"
Min. figure ~~[cm]~~	140	155
Max. figure ~~[cm]~~	158	170
S/T c-t ~~[mm]~~	356	406
S/T c-c ~~[mm]~~	0	0
T/T h ~~[mm]~~	550	575
T/T a ~~[mm]~~	544	557
H/T ~~[mm]~~	110	115
C/S ~~[mm]~~	420	420
W/B ~~[mm]~~	1052	1067
S/T ang. ~~[°]~~	74	73.5
H/T ang. ~~[°]~~	69	69.5
F/L ~~[mm]~~	475	475
B/B drop ~~[mm]~~	45	45
B/B width ~~[mm]~~	73	73
Reach ~~[mm]~~	0	0
Stack ~~[mm]~~	0	0
F/R ~~[mm]~~	43	43
Handlebars ~~[mm]~~	0	0
Stem ~~[mm]~~	0	0
Cranks ~~[mm]~~	0	0

max min

The recommended size and stature are just indicative. It is recommended to always consult your choice with the dealer.

S/T c-t - seat tube (center-top), length of the seat tube from the middle of BB parts to its peak
S/T c-c - seat tube (center-center), length of the seat tube from the middle of BB parts to an axle of the upper tube
T/T h - top tube horizontal, horizontal lenght of the upper tube
T/T a - top tube actual, real lenght of the upper tube
H/T - head tube, head tube lenght
C/S - chain stay, chain brace lenght
W/B - wheel base, wheelbase (front and rear axle lenght)
S/T ang. - seat tube angel, angle between the seat tube axis and an imaginary line connecting the axes of the front and rear wheel
H/T ang. - head tube angel, angle between the head tube axis and an imaginary line connecting axes of the front and rear wheels
F/L - fork length, fork length from the head parts bottom to the middle of the front wheel
B/B drop - bottom bracked drop, lenght between an imaginary line connecting wheels centers and BB parts, measured from BB parts
F/R - fork rake, distances between the head tube axis and fork axis measured at center of the front wheel, so-called. off set