Bicycle frame with angled strut
A bicycle includes a front wheel and a rear wheel and a frameset supported on the front wheel and the rear wheel. The frameset includes a main frame and a front fork rotationally coupled to the main frame. The main frame includes a top tube, a head tube rotationally supporting the front fork, a down tube coupling the head tube to a bottom bracket, a seat tube extending downward from the top tube and including a lower end spaced from the bottom bracket, a seatstay extending rearward from the lower end of the seat tube, and a strut member extending forward from the lower end of the seat tube and connecting the seat tube to the down tube.
1 . A bicycle comprising:
a front wheel and a rear wheel;
a frameset supported on the front wheel and the rear wheel, the frameset comprising a main frame and a front fork rotationally coupled to the main frame, the main frame comprising:
a top tube;
a head tube rotationally supporting the front fork;
a down tube coupling the head tube to a bottom bracket;
a seat tube including a lower end spaced from the bottom bracket, wherein the seat tube includes an opening at an upper end of the seat tube configured to receive a seat post, wherein a seat tube axis extends centrally down through the opening and to the lower end of the seat tube;
a seatstay extending rearward from the lower end of the seat tube;
a chainstay;
a strut member extending forward from the lower end of the seat tube and toward a portion of the down tube that is closer to the bottom bracket than to the head tube; and
a rear dropout attaching the rear wheel to the frameset;
wherein the top tube extends between the seat tube to the head tube, wherein the top tube is spaced apart from the down tube, wherein a distance between a rearward end of the top tube and a rearward end of the down tube is greater than a distance between the top tube and the down tube at the head tube, and wherein the seat tube axis extends to a point of intersection between the seat tube, the seatstay, and the strut member;
wherein the chainstay includes a rear end near the rear dropout, and the seatstay includes a rear end positioned above the rear end of the chainstay;
wherein an angle between the chainstay and the seatstay is between 10 degrees and 50 degrees, wherein an angle between the seatstay and the strut member is between 130 degrees and 170 degrees.
2 . The bicycle of claim 1 , wherein an angle between the strut member and the down tube is between 40 degrees and 80 degrees, and wherein an angle between the down tube and the chainstay is between 100 degrees and 140 degrees.
3 . The bicycle as claimed in claim 2 , wherein the down tube has a length, and wherein the strut member connects to the down tube at the portion of the down tube that is spaced from the bottom bracket a distance that is at least 15% of the length of the down tube.
4 . The bicycle as claimed in claim 2 , wherein an angle between the head tube and the down tube is between 90 degrees and 150 degrees.
5 . The bicycle as claimed in claim 2 , wherein an angle between the head tube and the down tube is equal to an angle between the down tube and the strut member.
6 . The bicycle as claimed in claim 2 , wherein the strut member defines an effective strut angle that is between 90 degrees and 150 degrees relative to the seat tube.
7 . The bicycle as claimed in claim 2 , wherein the strut member defines an effective strut angle that is between 100 degrees and 140 degrees relative to the seat tube.
8 . The bicycle as claimed in claim 2 , wherein the strut member defines an effective strut angle that is between 110 degrees and 130 degrees relative to the seat tube.
9 . The bicycle as claimed in claim 2 , wherein the strut member defines an effective strut angle relative to the down tube, and wherein the chainstay defines an effective chainstay angle relative to the down tube that is within 10 degrees of the effective strut angle.
10 . The bicycle as claimed in claim 2 , wherein the strut member has a width perpendicular to a center plane that extends along a length of the bicycle between the front wheel and the rear wheel, and a thickness perpendicular to the width and in the center plane, and wherein a portion of the strut member has a width:thickness ratio of at least 1.5.
11 . The bicycle as claimed in claim 1 , wherein the down tube has a length, and wherein the strut member connects to the down tube at the portion of the down tube that is spaced from the bottom bracket a distance that is at least 15% of the length of the down tube.
12 . The bicycle as claimed in claim 1 , wherein an angle between the head tube and the down tube is between 90 degrees and 150 degrees.
13 . The bicycle as claimed in claim 1 , wherein an angle between the head tube and the down tube is equal to an angle between the down tube and the strut member.
14 . The bicycle as claimed in claim 1 , wherein the strut member defines an effective strut angle that is between 90 degrees and 150 degrees relative to the seat tube.
15 . The bicycle as claimed in claim 1 , wherein the strut member defines an effective strut angle that is between 100 degrees and 140 degrees relative to the seat tube.
16 . The bicycle as claimed in claim 1 , wherein the strut member defines an effective strut angle that is between 110 degrees and 130 degrees relative to the seat tube.
17 . The bicycle as claimed in claim 1 , wherein the strut member and the chainstay are substantially parallel.
18 . The bicycle as claimed in claim 1 , wherein the strut member has a width perpendicular to a center plane that extends along a length of the bicycle between the front wheel and the rear wheel, and a thickness perpendicular to the width and in the center plane, and wherein a portion of the strut member has a width:thickness ratio of at least 1.5.
19 . The bicycle as claimed in claim 1 , wherein the rear dropout is proximal to the rear end of the chainstay and to the rear end of the seatstay.
20 . The bicycle as claimed in claim 1 , wherein the rear dropout includes a frame element that connects the rear end of the chainstay with the rear end of the seatstay.