Name: SPCK 4-bolt front sprocket
SKU: BPDFSPCK400EN
Availability: InStock

SPCK 4-bolt front sprocket

49,99€

The SPCK BMX 4-bolt front sprocket is ultra light, a definite advantage for the performance of your young riders (kids).

- Centre distance : 104 mm – 4-bolt fixing for reduced chain pitch
- Size : 67 to 73 teeth
- Weight : 31 g to 35 g depending on the number of teeth
- Colour : golden
- Material : 7075 aluminium
- Surface treatment: hard anodised

Choose your SPCK front sprocket

Size

67 teeth
68 teeth
69 teeth
70 teeth
71 teeth
72 teeth
73 teeth
74 teeth
76 teeth
75 teeth

Clear

SKU: BPDFSPCK400EN Categories: BMX Front sprocket, BMX Race, BMX Race drivetrain, BMX Race Parts Tags: BMX Race, Drivetrain, Parts

SPCK 4-bolt chain Kit

SPCK 4-bolt drivetrain kit + tools

SPCK 4-bolt drivetrain kit + tools + chain tensioner

SPCK 4-bolt drivetrain kit - stainless steel cog

SPCK 4-bolt drivetrain kit – 27 teeth cog + Chain tensioner

Description
Additional information

Description

The special shape of the SPCK Kids BMX 4-bolt front sprocket is the result of optimisation using Finite Element Method (FEM) simulation. This increases resistance and significantly reduces weight.

The AllYoogs® front sprockets are machined by CNC in France from 7075-T6 aluminium (stronger than 6061). This material guarantees lightness and above all a very high resistance of the product thanks to the hard anodising. This treatment gives our products a longer life.

The SPCK chain kit is a definite advantage for young riders. In fact, our SPCK drivetrain brings a measured gain of between 2 and 2.8% on lap times, and makes it easier to learn to “start”, manuals… It’s currently the lightest on the market.

We offer a wide range of teeth suitable for children. We advise you to consult our comparison table to choose the right front sprocket and improve your rider’s performance.

- Our SPCK 4-bolt front sprocket can be fitted to BMX bikes up to frame size “EXPERT” (weight limit 45kg = 99lb).
- Thanks to the SPCK 27-teeth stainless steel sprocket with the SPCK chain tensioner, it is possible to push the limits of our kit up to “PRO” frames (weight limit 50kg = 110lb).
- The SPCK chain kit is only compatible with SPCK race parts.
- Patent Pending
- Designed and developed by AllYoogs. Made in France
To learn more about the concept of our chain kit, we suggest you read our article.

How to choose your BMX 4-bolt front sprocket ?

Development calculated in mm with a 20 x 1.1/8 tyre
Development calculated in mm with a 20 x 1.3/8 tyre

1. Development calculated in mm with a 20 x 1.1/8 tyre

In the table below, find the value indicated at the intersection of the front sprocket and the cog of your child.

Example: cog = 16 and front sprocket = 37. The value to take into account = 376,3

	CLASSIC FRONT SPROCKET 4-bolt 104 mm – 20 x 1.1/8 TYRE
REAR SPROCKET	32	33	34	35	36	37	38	39	40	41	42	43	44	45
18	289,3	298,3	307,4	316,4	325,5	334,5	343,6	352,6	361,6	370,7	379,7	388,8	397,8	406,8
17	306,3	315,9	325,5	335,0	344,6	354,2	363,8	373,3	382,9	392,5	402,0	411,6	421,2	430,8
16	325,5	335,6	345,8	356,0	366,2	376,3	386,5	396,7	406,8	417,0	427,2	437,3	447,5	457,7
15	347,2	358,0	368,9	379,7	390,6	401,4	412,3	423,1	434,0	444,8	455,7

To obtain the SPCK equivalence :

In the table, find the values closest to those in the table above (higher values). The value to be taken into account is the one with the smallest cog.

Example with 376,3: the closest values are 378 and 379,7. The smallest cog is 30, so the choice is a 30 cog with a 70 front sprocket.

AllYoogs	SPCK FRONT SPROCKET 4-bolt 104mm – 20 x 1.1/8 TYRE
SPCK REAR SPROCKET	67	68	69	70	71	72	73
34	320,7	325,5	330,3	335,0	339,8	344,6	349,4
33	330,4	335,3	340,3	345,2	350,1	355,1	360,0
32	340,7	345,8	350,9	356,0	361,1	366,2	371,2
31	351,7	357,0	362,2	367,5	372,7	378,0	383,2
30	363,4	368,9	374,3	379,7	385,1	390,6	396,0
29	376,0	381,6	387,2	392,8	398,4	404,0	409,6
28	389,4	395,2	401,0	406,8	412,6	418,5	424,3
27	403,8	409,8	415,9	421,9	427,9	434,0	440,0

2. Development calculated in mm with a 20 x 1.3/8 tyre

In the table below, find the value indicated at the intersection of the front sprocket and the cog of your child.

Example: rear sprocket = 16 and front sprocket = 40. The value to take into account = 421

	CLASSIC FRONT SPROCKET 4-bolt 104 mm – 20 x 1.3/8 TYRE
REAR SPROCKET	32	33	34	35	36	37	38	39	40	41	42	43	44	45
18	299,4	308.7	318.1	327.4	336.8	346.1	355.5	364.8	374.2	383.6	392.9	402.3	411.6	421,0
17	317.0	326.9	336.8	346.7	356.6	366.5	376.4	386.3	396.2	406.1	416.0	425.9	435.8	445,7
16	336.8	347.3	357.8	368.4	378.9	389.4	399.9	410.4	421.0	431.5	442.0	452,5	463,1	473,6
15	359.2	370.5	381.7	392.9	404.1	415.4	426.6	437.8	449,0	460,3	471,5

To obtain the SPCK equivalence :

In the table, find the values closest to those in the table above (higher values). The value to be taken into account is the one with the smallest cog.

Example with 421: the closest values are 423,9 and 424,1. The smallest cog is 27, so the choice is a 27 SPCK stainless steel cog with a 68 front sprocket.

AllYoogs	SPCK FRONT SPROCKET 4-bolt 104mm – 20 x 1.3/8 TYRE
SPCK REAR SPROCKET	67	68	69	70	71	72	73
34	331.8	336.8	341.7	346.7	351.6	356.6	361.5
33	341.9	347.0	352.1	357.2	362.3	367.4	372.5
32	352.6	357.8	363.1	368.4	373.6	378.9	384.1
31	363.9	369.4	374.8	380.2	385.7	391.1	396.5
30	376.1	381.7	387.3	392.9	398.5	404.1	409.7
29	389.0	394.8	400.7	406.5	412.3	418.1	423.9
28	402.9	408.9	415.0	421.0	427.0	433.0	439.0
27	417,9	424,1	430,3	436,6	442,8	449,0	455,3

Depending on your child’s particularities (difficulty in starting, saturation…), we can be even more precise in the choice of our SPCK chain kit. Don’t hesitate to contact us by phone or whatsapp, we are here to help you!