Custom trike gearing help, with TC.

[Triple a arsenal]

On the mini bike I'm running a TC with 19" tires and a ratio of 7:2 and it rides good, take off is ok but takes awhile before I hit 40mph. From what Iv read the TC needs to be able to go into overdrive so a 72t worked for that in the rear. It's a cruiser so I'm happy with that.

This trike will have 16.5 x 6.5-8 tires, a TC with either a 10t or 12t jackshaft sprocket
And I'm trying to decide on the rear sprocket size.

I'm using a 212cc engine so a 30 series TC is what I'll use. I'll be using it on grass and street so what ratio would you guys recommend ?

I want something that takes off good and hits 40 or higher on the street, but I don't know if I'll get that with this setup.

 

[KartFab]

I cant give you specifics, but remember its a trade off.

I have three mini bikes geared for 36 mph and they have decent take off torque and a nice top speed (for my comfort zone). One that I modified went up to about 46 mph and I didnt feel too stable. Same gearing.

If you really want one that has BOTH good take off speed and 40 mph+ you are looking at about a $70 investment in a high flow intake, exhaust, and jet combined with a governor removal and direct throttle.

If its a smallish trike, and you dont have that pcv on the wheels, gear it for 30-36 mph at 3600 rpm, then pick up the extra speed from your engine mods. Just my 2 cents.

 

[Triple a arsenal]

I cant give you specifics, but remember its a trade off.

I have three mini bikes geared for 36 mph and they have decent take off torque and a nice top speed (for my comfort zone). One that I modified went up to about 46 mph and I didnt feel too stable. Same gearing.

If you really want one that has BOTH good take off speed and 40 mph+ you are looking at about a $70 investment in a high flow intake, exhaust, and jet combined with a governor removal and direct throttle.

If its a smallish trike, and you dont have that pcv on the wheels, gear it for 30-36 mph at 3600 rpm, then pick up the extra speed from your engine mods. Just my 2 cents.

The trike has dot approved tires and wheels, I was looking for the ratio the TC performs its best. Iv read 6.0 it works it's best but maybe someone has done multiple setups? I have a 7.2 and it's good but thinking to try 6.0 or lower.

 

[KartFab]

if you gear for 28-35ish mph at 3600 rpm, that is the typical range for the average go kart.

 

[bob58o]

Assuming you gear 6:1 and can reach ungoverned RPMs of 5200....
6 x 0.9 = 5.4 (TC overdrive)
5200 RPM / 5.4 = 963 Axle rev / min
16.5 x 3.14159 /12 = 4.32 ft/rev
4.32 x 963 = 4160 ft per min
4160 x 60 = 249,591 ft per hr
249,591 /5280 = 47 mph

But you wont get to 5200 RPMs with 6:1 gear ratio. I don't think.


A 7 or 7.5:1 ratio is what you want I think.

---------- Post added at 03:32 AM ---------- Previous post was at 03:24 AM ----------

I had a 212 with TC, 6:1 gear ratio, and 16" tires. It was a heavy buggy and topped out at 41 mph.
After switching to 7.5:1 it was more fun for me. (I have a small field to play in). I still hit 36 mph but had more low end.

 

[Triple a arsenal]

Assuming you gear 6:1 and can reach ungoverned RPMs of 5200....
6 x 0.9 = 5.4 (TC overdrive)
5200 RPM / 5.4 = 963 Axle rev / min
16.5 x 3.14159 /12 = 4.32 ft/rev
4.32 x 963 = 4160 ft per min
4160 x 60 = 249,591 ft per hr
249,591 /5280 = 47 mph

But you wont get to 5200 RPMs with 6:1 gear ratio. I don't think.


A 7 or 7.5:1 ratio is what you want I think.

---------- Post added at 03:32 AM ---------- Previous post was at 03:24 AM ----------

I had a 212 with TC, 6:1 gear ratio, and 16" tires. It was a heavy buggy and topped out at 41 mph.
After switching to 7.5:1 it was more fun for me. (I have a small field to play in). I still hit 36 mph but had more low end.

Exactly what I wanted to know , the 7.2:1 on the mini bike is what it took for TC to actually go into overdrive. Before I did the 72t in the rear, the motor was running out of steam before the TC would. Now the motor keeps up with TC and it's a smooth ride at 40-45mph, takes a long stretch to get there but she purrs.

I didn't know if the same applied for trike.