Sprockets & Speed

**Sprocket Speed** - Decided to make this a sticky since so many people are asking about sprockets ENJOY!!!


So for gptc I am running 7/74 or 7/70


here you go all *** To read this below - the "6" "78" is the sprocket size front then rear. the numbers starting with 13.000 is speed in kph @ 8,000 RPM & it works up from there ***

F/R Gear Ratio 8K 8500 9K 9500 10K 10500 11K 11500 12K 12500 13K 13500 14K
6 78 13.000 33 35 37 39 41 43 45 47 49 51 53 55 57
6 72 12.000 35 38 40 42 44 46 49 51 53 55 58 60 62
6 70 11.667 36 39 41 43 46 48 50 52 55 57 59 61 64
6 68 11.333 37 40 42 45 47 49 52 54 56 59 61 63 66
6 66 11.000 39 41 43 46 48 51 53 56 58 60 63 65 68
6 65 10.833 39 42 44 47 49 51 54 56 59 61 64 66 69
6 64 10.667 40 42 45 47 50 52 55 57 60 62 65 67 70
6 63 10.500 40 43 46 48 51 53 56 58 61 63 66 68 71
6 62 10.333 41 44 46 49 51 54 57 59 62 64 67 69 72
6 60 10.000 42 45 48 50 53 56 58 61 64 66 69 72 74

7 78 11.143 38 41 43 45 48 50 52 55 57 60 62 64 67
7 72 10.286 41 44 46 49 52 54 57 59 62 65 67 70 72
7 70 10.000 42 45 48 50 53 56 58 61 64 66 69 72 74
7 68 9.714 44 46 49 52 55 57 60 63 66 68 71 74 77
7 66 9.429 45 48 51 54 56 59 62 65 68 70 73 76 79
7 65 9.286 46 49 51 54 57 60 63 66 69 72 74 77 80
7 64 9.143 46 49 52 55 58 61 64 67 70 73 76 78 81
7 63 9.000 47 50 53 56 59 62 65 68 71 74 77 80 83
7 62 8.857 48 51 54 57 60 63 66 69 72 75 78 81 84
7 60 8.571 50 53 56 59 62 65 68 71 74 77 81 84 87

8 78 9.750 44 46 49 52 54 57 60 63 65 68 71 74 76
8 72 9.000 47 50 53 56 59 62 65 68 71 74 77 80 83
8 70 8.750 49 52 55 58 61 64 67 70 73 76 79 82 85
8 68 8.500 50 53 56 59 62 66 69 72 75 78 81 84 87
8 66 8.250 52 55 58 61 64 68 71 74 77 80 84 87 90
8 65 8.125 52 56 59 62 65 69 72 75 78 82 85 88 92
8 64 8.000 53 56 60 63 66 70 73 76 80 83 86 90 93
8 63 7.875 54 57 61 64 67 71 74 78 81 84 88 91 94
8 62 7.750 55 58 62 65 69 72 75 79 82 86 89 93 96
8 60 7.500 57 60 64 67 71 74 78 81 85 89 92 96 99

9 78 8.667 49 52 55 58 61 64 67 70 74 77 80 83 86
9 72 8.000 53 56 60 63 66 70 73 76 80 83 86 90 93
9 70 7.778 55 58 61 65 68 72 75 79 82 85 89 92 96
9 68 7.556 56 60 63 67 70 74 77 81 84 88 91 95 98
9 66 7.333 58 62 65 69 72 76 80 83 87 91 94 98 101
9 65 7.222 59 63 66 70 74 77 81 85 88 92 96 99 103

9 64 7.111 60 63 67 71 75 78 82 86 90 93 97 101 105
9 63 7.000 61 65 68 72 76 80 83 87 91 95 99 102 106
9 62 6.889 62 66 69 73 77 81 85 89 93 96 100 104 108
9 60 6.667 64 68 72 76 80 84 88 92 96 100 104 108 112

thought i'll add to that :lol:

Front sprocket:
Adding a tooth to the front sprocket will increase top end speed (less low-end acceleration), remove a tooth to increase acceleration (lower top speed).

Rear sprocket:
The rear sprocket is the exact opposite as the front. Adding a tooth to the rear sprocket will increase acceleration (less top speed), remove a tooth to increase top speed (less low-end acceleration). You should also note that a 3 tooth change in the rear sprocket is equal to one tooth change in the front sprocket.

A general guideline is if you ride or race on a tight track without a lot of long straights, then you should run lower gearing (to improve acceleration). On bigger tracks with big sweeping turns and long straights, higher gearing would be best. Stock 50 gearing is 14t front and 37t rear

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Good job on the sprocket info guys

wow, i was looking for this.. thanks alot of the info

I was wondering on how that all worked out. I am glad I saw this. Seeing as I have a Straight away that I really just mess around on I can make sure I get the top end.

Thanks Much

I was wondering on how that all worked out. I am glad I saw this. Seeing as I have a Straight away that I really just mess around on I can make sure I get the top end.

Thanks Much

hmm yes but just a question, to get top speeds of 100km/h, how much power would the bike be having to make, and what would be the maximum weight of the rider?

oh and .yes. i do like that table =p


cheers
[~]

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CAG 49cc :: Resprayed Black w/ light green highlights
---> 10° Advanced Timing Key, Triple Stage Reeds, Revs Unlimited 49cc Head Kit (RED), Race Clutch Springs, VT10 Fuel Filter, High Quality Fuel Lines, Steel Pegs (BLACK), 6/78T Gearing, FatBoy Exhaust, Lightened Flywheel

the more horsepower the engine has the quicker the bike will get to max speed. a stock engine will get to max speed if you have enough straight.

Is there any way to find out the size of the stock sprockets on my cag besides counting all the teeth? And i would have thought a standard cag engine would exploded or something goin 100km/h. My bike over heats if i go 50km/h for 20mins or so

stock is stock. after market rear sprockets do have certain prints which is easily identified eg 60 , 70 ect. its not hard to count is it ? also when say a stock cag is fitted with gearing to get to the 100 k mark you must remember that this will take some straight track but revs will still be simular, its the gear down process. lets say your engine is running at 10,000 rpms with a 6 - 68 ratio and you only get 60 kmph top speed, if you go to say a 9-60 ratio and when your engine reaches 10,000 rpms i would say you are going alot faster than 60 ks.