What country will you be racing in?
I would go to the national federation's website and look at the rules.
Edit:
USAT Rules from here:
https://www.teamusa.org/...tive-Rules#Article_V 5.11 Bicycle Specifications. All bicycles and bicycle equipment used in USA Triathlon sanctioned events must conform to the specifications set forth in this Section. Any participant using a nonconforming bicycle or otherwise violating this Section shall be disqualified.
(a) Length cannot exceed two meters, and width cannot exceed 75 centimeters.
(b) The distance from the ground to the center of the chain wheel axle must measure at least 24 centimeters.
(c) A vertical line touching the front most point of the saddle may be no more than 5 centimeters in front of and no more than 15 centimeters behind a vertical line passing through the center of the chain wheel axle. The cyclist must not have the capability of adjusting the saddle beyond these limits during competition.
(d) The "front-to-center" distance, which is defined as the distance between a vertical line passing through the center of the chain wheel axle and a vertical line passing through the center of the front axle, must measure not less than 54 centimeters, except where the distance between the center of the chain wheel axle and the top of the saddle is less than 71 centimeters. In this case the front-to-center distance cannot be less than 50 centimeters. The "front-to-center" distance must measure not more than 65 centimeters, or seven eighths of the distance between the center of the chain wheel axle and the top of the saddle, whatever is greater. Applicability of the two foregoing exceptions is determined by measuring from a point on top of the saddle which is 14 centimeters behind the front most point of the saddle.
(e) There must be no protective shield, fairing, or other device on any part of the bicycle (including frame, wheels, handlebars, chain wheel, and accessories) which has the effect of reducing resistance. Aerodynamic carriers for food, water, and or cycling provisions may be attached to or be an integral part of the aero-handlebars if they meet the following guidelines:
(i) The carrier can pass from front to rear, through a rectangular loop with dimensions of 10 inches (25 cm) in width and 8 inches (20 cm) in height. (ii) The front of the carrier is behind the cyclist’s hands when the hands are placed in their customary position on the end of the aerobars, and (iii) the length of the carrier is no greater than 10 inches (25 cm) front to rear.
When the carrier is an integral part of the aerobar, this integrated unit must be able to pass through the rectangular loop defined in (i) above and the carrier portion of the unit must meet criteria (ii) and (iii). In the event that compliance with this section is in doubt with respect to any particular carrier or integrated unit, a member of USA Triathlon may submit the carrier or integrated unit to USA Triathlon for evaluation.
(f) No additional equipment, whether it is worn under the competitor's clothing, over the competitors clothing, or is otherwise attached to the athlete's body, which has the effect of reducing wind resistance is permitted. An exception is the use of safety helmets as described in Section 5.9. Such helmets may have the effect of reducing the wind resistance of the head only.
(g) Except as otherwise determined by the race director in the interest of safety, the front wheel may be of a different diameter than the rear wheel, but the front wheel must be of spoke construction. The rear wheel may be either spoke or solid construction. Wheel covers shall only be permitted on the rear wheel.
(h) No wheel may contain any mechanism which is capable of accelerating the wheel.
(i) Handlebars and stem must be fashioned to prevent any danger. All handlebar ends must be solidly plugged to lessen the possibility of injury.
(j) There must be one working brake on each of the two wheels.
(k) There must be a free-wheeling mechanism between the crank and the rear wheel that allows the bicycle to roll forward while the pedals remain stationary.
(l) All aspects of the bicycle must be safe to the user and to other participants in the event. Minimum safety standards include, but are not limited to, properly glued and sealed tires, tight headset and handlebars, and true wheels.