274 

14 CFR Ch. I (1–1–24 Edition) 

§ 25.731 

(2) A loose tire tread, unless it is 

shown that a loose tire tread cannot 
cause damage. 

(3) Possible wheel brake tempera-

tures. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–23, 35 FR 5676, Apr. 8, 
1970; Amdt. 25–42, 43 FR 2323, Jan. 16, 1978; 
Amdt. 25–72, 55 FR 29777, July 20, 1990; Amdt. 
25–75, 56 FR 63762, Dec. 5, 1991; Amdt. 25–136, 
77 FR 1617, Jan. 11, 2012] 

§ 25.731

Wheels. 

(a) Each main and nose wheel must 

be approved. 

(b) The maximum static load rating 

of each wheel may not be less than the 
corresponding static ground reaction 
with— 

(1) Design maximum weight; and 
(2) Critical center of gravity. 
(c) The maximum limit load rating of 

each wheel must equal or exceed the 
maximum radial limit load determined 
under the applicable ground load re-
quirements of this part. 

(d) 

Overpressure burst prevention. 

Means must be provided in each wheel 
to prevent wheel failure and tire burst 
that may result from excessive pressur-
ization of the wheel and tire assembly. 

(e) 

Braked wheels. Each braked wheel 

must meet the applicable requirements 
of § 25.735. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–72, 55 FR 29777, July 20, 
1990; Amdt. 25–107, 67 FR 20420, Apr. 24, 2002] 

§ 25.733

Tires. 

(a) When a landing gear axle is fitted 

with a single wheel and tire assembly, 
the wheel must be fitted with a suit-
able tire of proper fit with a speed rat-
ing approved by the Administrator 
that is not exceeded under critical con-
ditions and with a load rating approved 
by the Administrator that is not ex-
ceeded under— 

(1) The loads on the main wheel tire, 

corresponding to the most critical 
combination of airplane weight (up to 
maximum weight) and center of grav-
ity position, and 

(2) The loads corresponding to the 

ground reactions in paragraph (b) of 
this section, on the nose wheel tire, ex-
cept as provided in paragraphs (b)(2) 
and (b)(3) of this section. 

(b) The applicable ground reactions 

for nose wheel tires are as follows: 

(1) The static ground reaction for the 

tire corresponding to the most critical 
combination of airplane weight (up to 
maximum ramp weight) and center of 
gravity position with a force of 1.0g 
acting downward at the center of grav-
ity. This load may not exceed the load 
rating of the tire. 

(2) The ground reaction of the tire 

corresponding to the most critical 
combination of airplane weight (up to 
maximum landing weight) and center 
of gravity position combined with 
forces of 1.0g downward and 0.31g for-
ward acting at the center of gravity. 
The reactions in this case must be dis-
tributed to the nose and main wheels 
by the principles of statics with a drag 
reaction equal to 0.31 times the 
vertical load at each wheel with brakes 
capable of producing this ground reac-
tion. This nose tire load may not ex-
ceed 1.5 times the load rating of the 
tire. 

(3) The ground reaction of the tire 

corresponding to the most critical 
combination of airplane weight (up to 
maximum ramp weight) and center of 
gravity position combined with forces 
of 1.0g downward and 0.20g forward act-
ing at the center of gravity. The reac-
tions in this case must be distributed 
to the nose and main wheels by the 
principles of statics with a drag reac-
tion equal to 0.20 times the vertical 
load at each wheel with brakes capable 
of producing this ground reaction. This 
nose tire load may not exceed 1.5 times 
the load rating of the tire. 

(c) When a landing gear axle is fitted 

with more than one wheel and tire as-
sembly, such as dual or dual-tandem, 
each wheel must be fitted with a suit-
able tire of proper fit with a speed rat-
ing approved by the Administrator 
that is not exceeded under critical con-
ditions, and with a load rating ap-
proved by the Administrator that is 
not exceeded by— 

(1) The loads on each main wheel 

tire, corresponding to the most critical 
combination of airplane weight (up to 
maximum weight) and center of grav-
ity position, when multiplied by a fac-
tor of 1.07; and 

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