Abstract
The invention is directed to a valve stem system (1) for tubeless wheels. The valve stem system (1) includes a valve stem body (2) with a first end (3) and a second end (4), wherein the second end (4) is located in a tire/rim-volume when mounted at the wheel. A first valve (5) is arranged at the second end (4) of the valve stem body (2). The first valve (5) is a self-sealing one-way valve. A second valve (10) is removably mountable at the first end (3) and is, when mounted, at least partially housed in the valve stem body (2). The second valve (10) comprises a valve stem core inserted in the valve stem body (2) and can be added or removed from the valve stem body (2) while pressure is maintained within the tire by the first valve (5). The invention further concerns a probe (30) for a valve stem system, a method to test the amount of sealant in a wheel and a refilling assembly (80) for a wheel.
Claims
1. A valve stem system (1) for tubeless wheels, said wheels comprising a rim (50) and a tire (60), said valve stem system (1) comprising: a valve stem body (2) with a first end (3) and a second end (4), the second end (4) being located in the tire/rim-volume when mounted on the wheel; a first valve (5) comprising a self-sealing one-way valve arranged at the second end (4) of the valve stem body (2); and a second valve (10) removably mountable at the first end (3) and, when mounted, at least partially housed in the valve stem body (2), wherein the second valve (10) comprises a valve stem core inserted in the valve stem body (2) and wherein the second valve (10) can be added or removed from the valve stem body (2) while pressure is maintained within the tire/rim-volume by the first valve (5).
2. The valve stem system (1) according to claim 1, wherein the first valve (5) comprises at least one sealing lip (6) and at least one slit (7).
3. The valve stem system (1) according to claim 1, wherein the first valve (5) comprises a duckbill-type valve.
4. The valve stem system (1) according to claim 1, wherein the first valve (5) is formed as a single piece and comprises an outer sealing face (8).
5. The valve stem system (1) according to claim 1, wherein the first valve (5) is made of elastic material selected from the group consisting of rubber and silicone.
6. The valve stem system (1) according to claim 1, wherein the valve stem system (1) further comprises an annular sealing element (9) arranged at the second end (4) and inside of the valve stem body (2) or the first valve (5) and/or at the first end (3) and/or between the first and the second end (3,4) of the valve stem body (2) and having an inner opening of diameter (d).
7. The valve stem system (1) according to claim 6, wherein the annular sealing element (9) is integrally formed with the first valve (5).
8. The valve stem system (1) according to claim 1, wherein the second valve (10) comprises a Presta-type valve core or a Schrader-type valve core inserted in the valve stem body (2).
9. The valve stem system (1) according to claim 1, wherein the first valve (5) and the second valve (10) are two separate valves that are independent from one another.
10. The valve stem system (1) according to claim 1, wherein the first valve (5) and the second valve (10) are arranged in series such that inflating or deflating the tire (60) requires opening the first valve (5) and the second valve (10).
11. The valve stem system (1) according to claim 1, the system allowing sealant (70) to be added to or removed from the tire/rim-volume while the tire (60) is under pressure.
12. The valve stem system (1) according to claim 1, wherein the second valve (10) is removable to allow for filling in sealant (70) into the tire (60), removing sealant (70) from the tire (60) or controlling sealant (70) inside the tire (60), when the tire (60) is under pressure.
13. A valve stem system (1) for tubeless wheels, said wheels comprising a rim (50) and a tire (60), said valve stem system (1) comprising: a valve stem body (2) with a first end (3) and a second end (4), the second end (4) being located in the tire/rim-volume when mounted on the wheel; a first valve (5) comprising a self-sealing one-way valve arranged at the second end (4) of the valve stem body (2); and a second valve (10) removably mountable at the first end (3) and, when mounted, at least partially housed in the valve stem body (2) and operatively connected to the first valve (5) by a venting element (11) which extends through the valve stern body (2) to open the first valve (5), wherein the second valve (10) comprises a valve stem core inserted in the valve stem body (2) and wherein the second valve (10) can be added or removed from the valve stem body (2) while pressure is maintained within the tire/rim-volume by the first valve (5).
14. The valve stem system (1) according to claim 13, wherein the venting element (11) is a tube comprising at least one venting opening (12) arranged on a sidewall.
15. The valve stem system (1) according to claim 13, wherein the first valve (5) and the second valve (10) are two separate valves that are independent from one another.
16. The valve stem system (1) according to claim 13, wherein the first valve (5) and the second valve (10) are arranged in series such that inflating or deflating the tire (60) requires opening the first valve (5) and the second valve (10).
17. The valve stem system (1) according to claim 13, wherein the second valve (10) comprises a Presta-type valve core or a Schrader-type valve core inserted in the valve stem body (2).
18. The valve stem system (1) according to claim 13, the system allowing sealant (70) to be added to or removed from the tire/rim-volume while the tire (60) is under pressure.
19. The valve stem system (1) according to claim 13, wherein the second valve (10) is removable to allow for filling in sealant (70) into the tire (60), removing sealant (70) from the tire (60) or controlling sealant (70) inside the tire (60), when the tire (60) is under pressure.
20. Tubeless wheel, comprising a rim (50) and a tire (60), and further comprising a valve stem system (1) according to claim 1, the valve stem system (1) being mounted to the rim (50) of the tubeless wheel.
21. Tubeless wheel, comprising a rim (50) and a tire (60), and further comprising a valve stem system (1) according to claim 13, the valve stem system (1) being mounted to the rim (50) of the tubeless wheel.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] The herein described invention will be more fully understood from the detailed description of the given herein below and the accompanying drawings, which should not be considered as limiting to the invention described in the appended claims.
[0061] FIG. 1 shows a valve stem system mounted on a rim;
[0062] FIG. 2 shows a valve stem system;
[0063] FIG. 3 shows a section view of a valve stem body and a first valve;
[0064] FIG. 4 shows a section view of a valve stem body and a first valve;
[0065] FIG. 5 shows a valve stem system with a second valve mounted;
[0066] FIG. 6 shows a cross-cut through the valve stem system with a second valve of FIG. 5 along line A-A;
[0067] FIG. 7 shows a section view of a valve stem system with a second valve mounted;
[0068] FIG. 8 shows a valve stem system and a second valve;
[0069] FIG. 9 shows a section view of a valve stem system mounted on a rim;
[0070] FIG. 10 shows a probe for a valve stem system;
[0071] FIG. 11 shows a cross-cut through the probe of FIG. 10 along line B-B;
[0072] FIG. 12 shows detail C of FIG. 10;
[0073] FIG. 13 shows detail D of FIG. 11;
[0074] FIG. 14 shows a section view of a probe inserted in sealant;
[0075] FIG. 15 shows detail D of FIG. 14;
[0076] FIG. 16 shows detail E of FIG. 14;
[0077] FIG. 17 shows a section view of a probe inserted in sealant;
[0078] FIG. 18 shows a section view of a probe inserted in sealant;
[0079] FIG. 19 shows a section view of a probe;
[0080] FIG. 20 shows detail F of FIG. 19;
[0081] FIG. 21 shows detail G FIG. 19;
[0082] FIG. 22 shows a refill assembly;
[0083] FIG. 23 shows a valve system;
[0084] FIG. 24 shows the valve system in partially disassembled state;
[0085] FIG. 25a shows a refilling assembly;
[0086] FIG. 25b shows cross-section H-H of FIG. 25a;
[0087] FIG. 26 shows the refilling assembly of FIG. 25a partially disassembled;
[0088] FIG. 27 shows the plunger and the components stored in it;
[0089] FIG. 28 shows a refilling assembly in a first state;
[0090] FIG. 29 shows a refilling assembly in a second state;
[0091] FIG. 30a shows a probe in a perspective view;
[0092] FIG. 30b shows the probe of FIG. 30b in a front view;
[0093] FIG. 31 shows the probe of FIG. 30 in a first state in a back view and broken view, the second tube end being partially removed for illustrative purposes;
[0094] FIG. 32 shows the probe of FIG. 31 in a second state;
[0095] FIG. 33 shows detail I of FIG. 30;
[0096] FIG. 34 shows detail J of FIG. 31; and
[0097] FIG. 35 shows detail K of FIG. 32.
DETAILED DESCRIPTION OF THE INVENTION
[0098] FIG. 1 shows an embodiment of a valve stem system 1 mounted on a wheel rim 50 including with a tire 60 mounted, in particular a tubeless wheel. The tire 60 is filled with sealant 70 for sealing the tire. The valve stem system 1 protrudes outward the outer (centripetal) surface of the rim and is fastened at the rim 50 using a nut 14.
[0099] FIG. 2 shows an embodiment of a valve stem system 1 comprising a tubular valve stem body 2 and a first valve or valve element 5. The valve stem body 2 has a first end 3 and a second end 4 connected by a passageway which extends in longitudinal direction through the valve body 2. A cap 15, which can be threaded at the first end 3 of the valve stem body 2, is provided. The cap 15 protects the inner volume of the valve stem body 2 from pollution as well as it may serve as an additional sealing element to prevent the passage of pressurized gas through the valve stem body 2. The first valve 5 is arranged at the second end 4 of the valve stem body 2, hence it is arranged at the base of the valve stem system 1. The first valve 5 comprises an outer sealing face 8 as well as sealing lips 6. The two sealing lips 6 form a half-spherical essentially convex shape. In between the two sealing lips 6 there is the valve opening, which in this embodiment is a slit 7. The slit is in a closed state when the two sealing lips 6 are in contact. The sealing lips 6 extend in converging relationship to each other leading to an opening of the slit 7. On its outer surface, the valve stem body has an outer thread 13 which can be used to fasten the cap 15 or attach the valve stem system 1 to a rim e.g. by a nut.
[0100] FIG. 3 and FIG. 4 show two embodiments of a first sealing element 5 of the valve stem system. The first valve 5 is mounted at the second end of the valve stem body by means of an interlocking and/or a glued connection. The outer sealing surface 8 has a tapered shape and is essentially in parallel to a tapered part of the outer surface of the valve stem body 2, which allows for a mechanically advantageous load transmission between valve stem body 2 and rim 50 when mounted. As shown e.g. in FIG. 3, the sealing lips 7 may also have a rather limited extension in longitudinal direction of the valve stem system, resulting in the first sealing element 5 having a rather compact shape. A first sealing element 5 with such a shape may be less exposed to e.g. impacts on the tire resulting from curbs, stones or potholes.
[0101] Using a first valve 5 with convex sealing lips 6 helps to increase sealing of the slit 7. As shown in FIG. 4, the gas pressure in the tire/rim space acting on the outer surface of the sealing lips 6, schematically indicated with arrows P+, causes an increased contact force between the two sealing lips 6, schematically indicated with arrows r. This causes a higher contact pressure between the faces inside of the slit 7 and hence a tighter closure of the slit 7. As shown in FIG. 4, an additional sealing element 9 may be arranged at the second end of the valve stern body. As shown in FIG. 4 the additional sealing element may have an annular shape and may be part of the first valve 5, hence be integrally formed with the first valve 5. In contrast to FIG. 4, FIG. 3 shows an embodiment without such an annular sealing element 9.
[0102] FIG. 5 shows one embodiment of the valve stem system (1) with a second valve or valve element 10 mounted removably at the first end 3 of the valve stem body 2, partially housed within the valve stem body 2. The second valve 10 comprises a core rod 16, a core nut 17 and a bushing 18. The second valve 10 may be connected to the valve stem body 2 using a thread, as shown in FIG. 6. The assembling of the core rod 16, the nut 17 and the bushing 18 may be according to, or similar as for Presta-type or Schrader-type valve cores. FIG. 6 is a cross cut of FIG. 5 along line A-A. As can be seen, the core rod 16 has a first end and a second end. In mounted state, said first end may protrude outside of the first end 3 of the valve stem body 2, the second end is located inside of the valve stem body 2. A venting element 11 is arranged at the second end of the valve stem body 2. As shown in FIG. 6, the venting element 11 may have a tubular shape, comprising one or multiple venting openings 12 in its sidewall. Being mechanically operatively connected to the core rod 16, the venting element 11 serves as an extension of the core rod 16. FIG. 7 shows the valve stem system 1 of FIGS. 5 and 6 when inflating or deflating a tire. Therefore, the second valve 10 is unlocked by screwing off the core nut 17, as known e.g. from Presta-type valve cores. After that, the core rod 16 can be shifted towards the first valve 5, causing the venting element 11 to protrude the first valve 5 by opening the slit 7, resulting in a continuous valve opening between the two ends of the valve stem system 1. Consequently, air can continuously flow from the second side of the valve stem system into the venting element 11, through the venting opening 12 into the valve stem body 2 and sequentially through the channel between the bushing 18 and the core rod 16 to the first end 3 of the valve stem system 1, or vice versa in the other direction.
[0103] FIG. 8 illustrates an embodiment of a valve stem system 1 with the second valve 10 being removed from the valve stem body 2.
[0104] FIG. 9 shows a section view of the valve stem system 1 when being mounted on the rim. The first valve 5 is essentially located inside of the rim/tire space, preventing the pressurized air from escaping from the rim/tire space.
[0105] FIG. 10 shows a probe 30 for testing the amount of the sealant 70 in the tire 60. FIG. 11 shows a section view of the probe 30. The probe 30 comprises a tube 31 with a first tube opening 32 at a first tube end 33 and a second tube opening 34 at a second tube end 35 and a rod 36. The rod 36 has a first rod end 37 and a second rod end 38 as shown in FIG. 17. For testing the amount of sealant, the rod 36 is inserted into the tube 31 and is moveable in the axial direction, whereby the second rod end 38 is located inside of the tube 31. A retaining element 40 is attached to the first rod end 37 as a holding element and as a stopper to prevent the rod 36 from entirely entering into the tube 31. An orifice 39 is arranged in the tube wall to equalize the pressure inside and outside of the tube.
[0106] FIG. 12 shows that the second tube end 35 may be tapered, so that the probe can easily go through the first valve 5. In addition, the tapered second tube end 35 ensures that sealant 70 can flow into the tube 31 when the tube 31 is pressed against the tire 60.
[0107] FIG. 13, FIG. 16 and FIG. 21 show the probe 30 with a first probe sealing element 41 and a second probe sealing element 42. FIG. 13 shows one embodiment of the probe with the first probe sealing element 41 attached to the second rod end 37 and the second probe sealing element 42 attached to the inner wall of the tube 31. The second probe sealing element 42 may be a tubular element, which can be arranged on the inner wall of the tube 31, for example, by gluing. The first probe sealing element 41 may have a shape of drop or bung. The dimension of the first probe sealing element 41 should be adapted to the inner diameter of the tube 31 by considering the production tolerances to ensure the sealing. The first probe sealing element 41 can be made of elastic material. The second probe sealing element 42 may have a tubular shape. The inner diameter of the second probe sealing element 42 may be adapted to the outer diameter of the rod 36 by considering the production tolerances to obtain a further sealing. FIG. 19 and FIG. 21 show another embodiment of the probe 30 with the first probe sealing element 41 and the second probe sealing element 42 having a shape of o-ring. In this embodiment, the first probe sealing element 41 is arranged near the second rod end 37 and the second probe sealing element 42 is arranged between the first rod end 36 and the second rod end 37. However, the arrangement and the shape of the probe sealing elements 41, 42 are not limited to the variation described above.
[0108] As shown in FIG. 20, a mark 45 is formed or marked on the rod 36 with a position being visible to the user. It allows the user to clearly identify the position of the second rod end 38 relatively to the orifice 39, when inserted in the tube 31.
[0109] FIGS. 14 to 17 and FIG. 18 illustrate the process of testing the amount of sealant 70 in the tire 60. In a first step, the retaining element 40 is pushed down toward the first tube end 33 to a position, such that the first probe sealing element 41 is moved to a position below the orifice 39 (FIG. 14 and FIG. 16). The probe 30 is inserted through the slit 7 until the second tube end 35 reaches the tire. Normally, no sealant 70 enters into the tube 30. In a second step, the retaining element 40 is pulled up such that the first probe sealing element 41 is moved to a position above the orifice 39 (FIG. 17). This can be controlled by the user regarding the mark 45 on the rod 36. The sealant 70 enters into the tube 30 and a sealant column 44 has the same height as the sealant outside of the tube 30 in the tire. In a third step, the retaining element 40 is pushed down again toward the first tube end 33 to a position, such that the first probe sealing element 41 is moved to a position below the orifice 39 (FIG. 18). Thus the essentially continuous opening between the orifice 39 and the second tube end 35 is closed which prevents the sealant column from being able to move up or down in the tube 31. The tube 30 can then be removed out of the valve stem body 2 while keeping first probe sealing element 41 staying below the orifice. The amount of the sealant 70 can be read by comparing the sealant column 44 with the probe gradation 43 marked on the outer surface of the tube 30.
[0110] FIG. 22 illustrates a refilling assembly 80 for a wheel furnished with the valve stem system of the present invention. The refilling assembly 80 comprises a syringe 81, a check valve 83, an extension element 84 and an applicator element 85. The applicator element 85 can be inserted into the valve stem body 2 until it opens the first valve 5. The syringe comprises at least one syringe graduation 82.
[0111] FIGS. 23 and 24 show another embodiment of a valve stem system 1 in assembled, respectively partially disassembled state. As shown, this embodiment of a valve stem system comprises a fist valve 5 that has multiple sealing lips 6.
[0112] FIGS. 25a to 27 show a refilling assembly 80 which is designed such that its major components can be stored in a compact way. The refilling assembly 80 comprises a plunger 86 which will usually be positioned within a central opening of a barrel 90, forming a syringe 81. When the plunger 85 is mounted inside of the barrel 90, the space defined by the plunger 85, the plunger head 87, the plunger's thumb rest 92 and the barrel 90 is divided into compartments 88a-c, as can e.g. be seen in FIG. 25b. In the embodiment shown, in a first compartment 88a an extension element 84 of the refilling assembly 80 is positioned, together with a stopcock 91 (not visible in FIG. 25b). In a second compartment 88b an applicator element 85 of the refilling assembly 80 is positioned, as can be seen in FIGS. 25b and 26. In a third compartment 88c, two valve stem systems 1 are positioned, as can be seen in FIGS. 25b and 26. Thus such a variation of a refilling assembly may be sold e.g. for retrofitting a bicycle with new valve stem systems 1 together with a compatible refilling assembly 80. As shown in FIGS. 26 and 27, the shape of plunger 86 may be adapted to the shape of the components that are stored in the compartments 88a-c. Therefore, also holding means 89 may be formed in order to establish a snapping connection with the components for secure storage of them.
[0113] FIG. 27 also shows an embodiment of a refilling assembly 80 that comprises a relatively long applicator element 85 that has a relatively large inner diameter and a tapered end (lower end in FIG. 27). In addition, this embodiment of a refilling assembly 80 comprises a stopcock 91 that can be switched from a closed state, when no fluid can pass the stopcock 91, to an open state, when fluid can pass the stopcock. As shown in FIG. 28 the stopcock 84 has a first end which can be connected to the syringe 81 and a second end that can be connected to an extension element 84, which in the embodiment shown is a hose. In FIGS. 28 and 29 the barrel's 90 wall has been partially removed for illustrative purposes. As also shown in FIG. 28, the extension element 84 can be connected to the applicator element 85 which can be inserted through a valve stem system 1 into a tire 60. Also in such a refilling assembly 80, the valve stem system 1 successfully prevents pressurized air from escaping from the tire 60 prior to the insertion of the applicator element 85 as well as afterwards. In the embodiment shown, the applicator element 85 is inserted into the valve stem system 1 and hence the rim/tire space until the applicator element's 85 lower tapered end gets into contact with the tire 60. Usually, the stopcock 91 will be in the closed state until this insertion is complete and will then be switched to the open state. Thus the sealant 70 can be transferred to the syringe 81, resulting in a movement of the plunger 86 relatively to the barrel 90, as indicated in FIG. 28 by a dotted arrow. Thus, if wished be the user, essentially all sealant 70 can be removed from the tire 60, as shown in FIG. 29. This transfer may be driven or at least be assisted by the pressurized air in the tire. However, it is clear, that the refilling assembly may also be used after the tire/rim space has been depressurized. A complete removal of sealant 70 will usually be indicated by small air bubbles appearing in the extension element 84 (if it is made from an optically transparent material) and/or the syringe. As soon as the sealant 70 is removed, the stopcock 91 can be switched to the closed state and the syringe 81 may subsequently be disconnected from the stopcock 91 in order to allow for a proper inspection of the sealant 70. Thus by visual, mechanical or chemical means the amount of quality of the sealant 70 can be determined accurately. If needed, the amount of sealant may be adapted and/or it may be replaced by a new sealant 70. Subsequently the syringe 81 can be connected to the stopcock 91 again and the sealant 70 can be injected into the tire 80.
[0114] FIGS. 30a and 30b show an embodiment of a probe 30 for a valve stem system 1 (not shown) which allows particularly convenient measurements. The probe 30 comprises a tube 31 that has a second tube end 35 which can be inserted in a valve stem system 1. As for the embodiments of probes 30 shown in previous Figures, the tube 31 will usually be made from an optically transparent material. The first tube end (not visible) is arranged in a housing 46. The housing 46 comprises grip elements 47 which allow a convenient handling of the probe 30. The housing further comprises a display opening 48 which displays the position of a rod 36 (not shown) that is arranged inside of the tube 31, as will be explained in further details in FIGS. 31 to 35. The housing 46 shown in FIG. 30a further comprises two lateral buttons 52a, 52b which can be pressed together in order to operate the probe 30, as will be explained in the subsequent figures.
[0115] In FIG. 31 the inner shifting mechanism 51 of the housing 46 is shown. The shifting mechanism 51 of the embodiment shown comprises a spring element 53 which in this embodiment essentially has the shape of an omega, the two ends of the spring element 53 being fixedly connected to the housing 46 by anchors 54a-b. At a midpoint of the spring element 53 the spring element 53 is connected to the first rod end 37 of a rod 36, said rod being arranged in the tube 31, in a similar way as e.g. shown in FIGS. 10 to 21. The spring element 53 is slightly pre-stressed between the anchors 54a-b and first stoppers 55a-b. The spring is also in contact with the two lateral buttons 52a-b of the housing. The grip element is shown by 58. In FIG. 31 the shifting mechanism 51 is shown in a first configuration, the rod 36 being in a first position, hence the second rod end 38 is in a first distance from the second tube end 35, an orifice 39 in the tube 31 being sealed by a first probe sealing element 41 and a second probe sealing element 42, as shown in detail in FIG. 34. As shown in FIG. 33, in this first configuration, a mark 45 arranged on the first rod end 37 can be seen in the display opening 48 at a first reference mark 49a, indicating to a user that the rod 31 is in a first position with the orifice 39 being separated from the second tube end 35.
[0116] As shown in FIG. 32, by pressing the two lateral buttons 52a-b together (indicated by dotted arc arrows) the shifting mechanism 51 can be switched to a second configuration. Therefore, the spring element 53 is laterally squeezed, leading to an elongated shape of the spring element 53 and hence a displacement of the midpoint of the spring element, leading to a displacement of the rod 31 (indicated by the dotted straight arrow). Thus the first rod end 37 can be displaced until it is stopped by a second stopper 56. At the same time, third stoppers 57a-b prevent the two buttons 52a-b, respectively the spring element 53, from being deformed any further. Thus the spring being deformed to a maximum and the rod being displaced to a maximum, it is ensured that the rod is in a second position, as shown in FIG. 35. At this second position, the mark 45 in the display opening 48 would be at a second reference mark 49b (not shown). As shown, the orifice 39 is not separated from the second tube end 35 in this second position, allowing a leveling of the sealant (not shown) inside of the tube 31. As soon as the two lateral buttons 52a-b are not pressed together anymore, the shifting mechanism switches back to the first configuration as the spring element 53 flexes back into its original more circular shape, resulting in the rod 36 moving back to the first position with the orifice 39 being separated from the second tube end 35 again.
[0117] In embodiments, the first valve 5 and the second valve 10 are two separate valves that are independent from one another.
[0118] In embodiments, the first valve 5 and the second valve 10 are arranged in series such that inflating or deflating the tire 60 requires opening the first valve 5 and the second valve 10.
[0119] In embodiments, the system allows sealant 70 to be added to or removed from the tire/rim-volume while the tire 60 is under pressure.
[0120] In embodiments, the second valve 10 is removable to allow for the purpose of filling in sealant 70 into the tire 60, for removing sealant 70 from the tire 60 or for controlling sealant 70 inside the tire 60, when the tire 60 is under pressure.
[0121] In a further aspect of the invention, a wheel is disclosed, which comprises a rim 50 and a tire 60, and further comprises a valve stem system 1 as disclosed herein, the valve stem system 1 being mounted to the rim 50 of the wheel.
[0122] In embodiments, the wheel can be a tubeless wheel or a tubed wheel.
[0123] In further embodiments, the wheel can be a bicycle wheel and preferably a tubeless bicycle wheel.
