Finding the right balance...gears for low/high end?

[Talntedmrgreen]

Disclaimer...I'm at your mercy, as a newbie to modding carts. I searched so much today that I'm likely to get a talking to from my boss at work for excessive time on the 'net, and still haven't really come up with what I'm looking for as far as how changing gears may affect my cart's performance.

With the 23Vanny I got from Tom, I've got all the power and torque I need, and what I would like to do is maintain enough of that to climb and crawl through mud, sand, etc with 4 adults. Right now, that's super easy, and I don't need or want to burn rubber. The Vanny will break my 25's loose on pavement. Fun, but not necessary. I'd like to use that power where I beleive it will be of most benefit in my riding scenarios.

Crunching the numbers based off info I found in my searches, and considering I don't want to run WOT at the full 5500rpm (for piece of mind), I can only get 33mph out of the cart the way it sits. That lines up with what I'm seeing on GPS. I'm pretty satisified with that but it's got me thinking. I'd love to criuse at that 30-35 speed without holding the pedal to the floor, becuase I won't do that but in short bursts here and there. I'm left cruising at 20-25.

So I'm looking at what the 8:1 gears will do. 5000rpm with those would put my max speed in the high 40's (rare, and possibly re-governed to prevent it), and 'cruising' at 35mph would settle me to around 3700-3800rpm. That's before taking into consideration the clutch performace, etc. That's where my question lies...real world.

By going to an 8:1 gearset, how dramatically is my real world low end going to be impacted, and what kind of rpm will I see with a 30-35mph cruising speed? I would like to gain mph, so that I can get back out of the pedal and relax where a non-rev kit Vanny would run WOT. Steering control does not appear to ever be an issue again.

Any help, your own results, or corrections to my 'logic' would be aprpeciated! I really just wanted to throw it out there and hear what folks have seen happen in this or similar scenarios

[JcXtreme72]

I am interesting in knowing peoples opinions too. I read on here some where that the 8:1 gears actually kept the engine in torque curve longer so it actually pulled harder after the first couple feet.

[1989Marathon]

What gear set is in it now?(ratio)

[CART-ZILLA]

with those #"s probably stock 12.5:1... i want to do the same thing to mine too enquiring minds want to know

[Talntedmrgreen]

Yes...based on gps and math...12.478:1. Stock is listed as 12.5:1 I believe so I assumed I was set to stock.

[1989Marathon]

Without changing the clutching, you will have about 65% of the torque at the rear wheel that you had with the 12.5 gearing. That's still more than my 16hp vanny would make stock. If you feel that you lose too much on the low end, you can stiffen up the secondary clutch, as that's what senses the change in torque. Once the clutches fully shift, it's rpms that dictate speed.

[Talntedmrgreen]

I still have the 28 degree cam and power spring from my stock setup, if I felt I needed to change my shifting. I was setup that way, and just set it back to OEM 36 degree. I was running 30mph with less throttle with the 28, and had to give it a bit more juice with the 36 to get a full shift, and get back to 30. The 36 does begin it's shift a tiny bit sooner, which is nice..I think both would hit 33-ish up over 5000rpm.

I'm thinking I'd be just fine to put the spead gears in, and still maintain the grunt I'm after. I won't have a chance before my first real day long run. My current setup would be a good baseline for comparison, but I am not thrilled about the idea of the extra investment, without hearing actual results from someone who's tried it.

[BlackBerryHill]

If I read your posts correctly you have a stock motor without a rev kit. If this is the case you should not run your motor above the factory recommended rpm's. Tom will confirm this as I have had this conversation with him via telephone. The owners manual will tell you the max rpm's for your engine. Anything over the max rpm's will result in internal engine damage. Purchase the rev kit from Tom and install it before disconnecting the governor.

I have read other threads on here about the difference between 28 and 36 degree clutches. Most say they did not see a difference between the two at top speed. The 28 will provide better take off and helps compensate for oversized tires with a factory engine. With that 23 V-Twin you shouldn't notice any lag on take off.

As for the gears, the lower numerical gearing will provide more power on the low end with a slightly lower top speed. The higher the gearing the higher the top speed with less performance from a dead stop. You just need to decide if you are going to spend most of your time driving in locations that require low end torque or driving at higher top speeds.

Your top speed will depend on a variety of factors, such as wind drag, occupants, accessories, etc. Are you driving on level ground? If you are going uphill you will lose some top speed, yet downhill is the opposite. Tire pressure will have an impact on your top speed, the more air the higher the top speed.

You will learn to adjust your cart as you spend more time driving it, such as what amount of belt tension provides the best performance. Make sure your throttle cable is adjusted so that you can achieve wide open throttle. Verify that your brakes are not dragging, disc or drum both can be adjusted. Make sure your front end is aligned properly, the wrong camber and toe settings can reduce top speed and increase tire wear. The tread pattern of your tires can even make a difference in top speed.

I don't know if I was of any help, but these are all things that will influence top speeds. I'm always tinkering with my cart to get it to perform exactly the way I want. One thing is for sure with carts, they are never finished.

[CART-ZILLA]

"As for the gears, the lower numerical gearing will provide more power on the low end with a slightly lower top speed. The higher the gearing the higher the top speed with less performance from a dead stop. You just need to decide if you are going to spend most of your time driving in locations that require low end torque or driving at higher top speeds."......... Ok if i am reading corectly your saying that 12.5:1 's are faster than 8:1's or 6:1 setup ??? if so it is totaly oposite of that lower the number the faster you go !! search the speed calculator on here...

[Talntedmrgreen]

Blackberry...I'm sorry, I was too vauge above. No, it's not a stock motor...I have a 23 Vanguard with HiRev & cam kit. My driven clutch is currently set to stock. Zilla is correct...the lower the ratio, the higher your top end speed.

Outside factors aside...I know wind and weight will slow me down...I am just wondering if the lower ratio will rob me of too much low end grunt, and what kind of speed have people seen in the mid range of around 3600rpm.