Why would you switch drive ratio?
 

I looked around a little but didn't find what I was looking for. What is, or are, the reasons to switch your drive ratio? I saw that someone switched from 1.36 to 1.5 and their boat handled better. Why? If you have an ill mannered boat, wouldn't the manufacturer have installed the proper drive ratio for the best overall performance? I suppose production boat companies may have a huge inventory in a particular ratio and just run with it? The problem I have is that not many if any at all have ever put any "performance parts" on an Enticer so I don't have much guidance. Thanks for your comments.

Are you experiencing something in particular? Back in the day, there were often time very limited options on propeller sizes/pitches...so some would elect to change drive ratios to be able to work with what they had. As far as "handling better", not sure what that means?

think of it like this, if you change the gear ratio in your car how could it possibly affect the handling?

going to the 1:36 ratio lets you to not to need a pitch prop in a very high pitch numerically when you have a big hp motor.

I didn't understand the reason it helped in handling either hence my question. I've been all over OSO today and couldn't find that particular post again. Sounds like the only reason to switch is for a propeller. Thanks for your comments guys.

only suggestion i have is over 90 mph on mine i can get a slight walk. i just drop the littlest tab a can. my theory is it acts a little like training wheels. lol

drive for drive there is no way the handling would change, meaning if you have std height low water pickup bravo and did nothing but change the ratio for example. the only part that would change the way the boat runs is the props. if the props were crappy for the boat and after the ratio change the new props worked better then that is what changed. if they changed ratio but ran the original props then any change in handling would be because of engine response. i.e. the engines were lazy feeling and the response to steering or throttle changes was slow or struggling due to over propped or too much ratio then the ratio change would make the boat feel more responsive. it does not really "handle" better it just reacts better.

Prob 90% of V bottom Bravo 1 boats of have 1.5 drives. A few have 1.65's and those are often used for higher altitude boats.
Boats with 1.36 and 1.25 usually only go that route due to prop pitch limitations.

From what I've read over the years "in cats" most guys run 1.35's and if you switch to a 1.24 they recommend over 1200+ hp and lots of torque. I'm assuming the 1.24 wouldn't have the acceleration the 1.35's have but would be better suited for midrange cruising. I'd think same would apply to 1.50's and 1.36's

My experience with the subject....bought a 1.35 sportmaster lower used as I didn't have the coin to swing a new one....single 1000 hp pad vee....I had to drop down to a 26 pitch prop to get in my RPM range I wanted and the boat did NOT like it. Very touchy with steering and wanted to chine walk at all speeds. Could have had the prop worked probably but ended up going to 1.50 gears in the lower and back up to 28 pitch prop and it handled much better. As said, gear ratio had nothing to do with it as it was all in the prop. I will say on the flip side of that however that the boat does all around feel better with the 1.50...acceleration, mid range, and top end are all better again though most likely due to the prop.

Same here, have ran my donzi 21 with both 1.36 and 1.50. Both with bravo1 props. -2 cases.

Boat handled like crap with 1.36, switched to 1.50 and its awesome.

Prop rpm matters, thats my take on it that have done back to back testing..

As I understand this. I’m currently toying with redoing my gear ratio.

it’s the Difference between torque and top speed

torque:
the higher ratio will produce torque. My bravo 3 is setup in 2.0:1. This helps the boat get on plane (faster and stay there at slower speeds). What it loses is top end speed. I’m seriously jealous of you 3digit guys. But my boat spends most of its life high speed trolling in rough water. 6-8’ is normal here.

Top speed:
but lower ratios like 1.5, 1.36 etc will allow much higher top end speed assuming it has enough torque to get on plane. Of course props factor into this equation etc. I have 20p and 22p duo props but I expect I’ll be propping all way out to 24-26p to compensate for my torque monster. And remember I’m on a dual prop which seem to be geared differently than normal single props. I wanted the boat to run straight when I need to leave helm to wrestle in a fish if I had no competent help on Baird. Trust me that struggle is real.

similar to truck towing axle ratios the higher the number more it can tow (torque) but lower top end speed and worse fuel economy.

this is my best understanding and many much more knowledgeable people on this board. But I’m starting to toy with this myself but I want to find the perfect setup now and then start making small changes before I get too radical (gear change).

Couple of main reasons (and many more specific reasons, for tweaking performance):

Here's a 'main reason' example: if you're running a 36 B1 4 blade, the prop is terrible. You may wish to drop from 1.50's to 1.36's, to get to a b1 29/30/32 4 blade, which handles much better. You won't necessarily 'lose' acceleration, if you re-pitch properly. Before changing drive gears, you may perhaps speak with an expert to see if changing to a different Prop rake, brand, different number of blades, larger / smaller diameter, etc... Obviously changing props will also effect the attitude and performance of your boat... hence, the consideration of finding what prop works best for your boat, and then backing into the rest, considering the boat, it's set-up, power and drive package, etc...

Another of the 'main reasons' for daily boaters is ease of getting on plane.... which is simply achieved in more of a 'macro' step (re-gearing) vs the micro, changing props. For example, many T/S TG's were not fond of getting on plane with B1 4B 32P props. Most TG owners agree changing / tweaking the prop was a better solution (for 525 and similar powered boats) vs than the drive gears (unless you were willing to give up top-end for mid-range performance).

Bottom line... get a professional to assist... and if not, having your buddy film you as you cruise by is an easy way for 'you' to see the attitude of the boat, as you're making changes, vs taking your buddy's word for it.

Hope that helps.