Hydro Mudder Goal is 17+ MPH

As most of you know I Redneckcomputergeek hate when some one says you cant do it.  Having already set a high bar for my self with Maine Mud Mowers build (See build log here https://www.atltf.com/t1612-been-there-done-that ). I think its time to take a look at the much hated world of hydro's.  Now I'm not the first to want to mud a hydro and others have worked on making then faster with pulley swaps and seen mixed results to say the least.  But to my knowledge none of them have broken past 12mph let alone the 17 to 20 I hope to hit.  So well everyone else was sleeping I got to work.





They say a picture is worth a thousand words but I think video does it much better!

Wouldnt you want the sprockets to be the other way? The large one on the hydro and the small on the live axle? Because the way it is now it would be gear reduced even more and go slower?

MoWheeler wrote:

Wouldnt you want the sprockets to be the other way? The large one on the hydro and the small on the live axle? Because the way it is now it would be gear reduced even more and go slower?

MoWheeler is correct, the way it is now the gears would be reduced!

It would be slow but could pull a mountain if you got traction!

MoWheeler wrote:

Wouldnt you want the sprockets to be the other way? The large one on the hydro and the small on the live axle? Because the way it is now it would be gear reduced even more and go slower?

Ok so now the fact I messed up at the end is out of the way. What do you guys think will it work?

yes, this should work, we have a scotts hydro, and it is nice to drive, it would be great if it where faster, though. once I got a taste of speed, I wanted more lol.

I would say so. It should scoot pretty good as long as your engine can run the hyro pump.

I'm just wondering to see how much the big sprocket protrudes thru the fenders, and I think you have to cut the axle off the stock hydro.

in my experience hydros mud pretty good, but you cant have the clutch half way out and 'creep' with 'em

looks like a solid plan to me, any plans on a oil cooler for the hydro? My prediction is that it will work, but the hydro unit will overheat, and possibly burn up due to it doing 3x the work that it was designed to do. if you can get a cooler/ bigger reservoir to bump up the oil capacity on the hydro it would help the longevity alot. my 2 cents

Creepycrawler wrote:

looks like a solid plan to me, any plans on a oil cooler for the hydro? My prediction is that it will work, but the hydro unit will overheat, and possibly burn up due to it doing 3x the work that it was designed to do. if you can get a cooler/ bigger reservoir  to bump up the oil capacity on the hydro it would help the longevity alot. my 2 cents

Yep! ^^^^ Nothing worse than geting your preject done and riding it for a short time only to break it. Believe me... I would know.

Creepycrawler wrote:

looks like a solid plan to me, any plans on a oil cooler for the hydro? My prediction is that it will work, but the hydro unit will overheat, and possibly burn up due to it doing 3x the work that it was designed to do. if you can get a cooler/ bigger reservoir  to bump up the oil capacity on the hydro it would help the longevity alot. my 2 cents

on that note, I have a hydro gear 310-510 hydrostatic trans, it will be easy to put a oil cooler on it but I would need a external pump and auto trans cooler off a truck with hose and I need to drill and tap a fitting off the lowest point of the tranny.
I can push about 12mph on it but I cant pull any thing at that speed or at all. try pulling a 14'x8' 800lbs trailer with 12 40-50lbs bales and a person on it, I will go up a hill but the 10cc pump in the trans isn't powerfull enough with a 22.2:1 ratio.

yeah, our scotts hydro stopped working after my dad used it to drag logs up a 100 foot incline (it is so steep that a mower would flip over if you tryed to drive it down there) I had to finish the job with the MTD (after an hour the belts where dead) then the Murray in its former self filled in until its tiers went flat and ITS belt was bunt. (it wasn't long.)

So what sets the restrictions in a hydro? Is it the motor's cc?

Thunderdivine wrote:

So what sets the restrictions in a hydro? Is it the motor's cc?

Internal gearing i think

also if you have room under the hood??? Try a tranny cooler and e fan stock alternator should do okay with the fan.. or put it on a switch when going over 8-10 flip it on..

I'm watching this one closely to see how it turns out. The theory is pretty sound, indeed. But I'm wondering about side effects. I think with the overdrive, you'd lose a lot of the natural braking a hydro usually offers. I'm also quite interested to see (and it's be better to FEEL it) what it drives like, overall. Will coasting be effect, or even possible? Will it hold up to the strain and possibly heat?

All in all, many of us have thought of or suggested the concept. Hat's off to you for taking the plunge and actually putting it into motion... Literally!

I would put a pillow block in the middle of the frame for some, not a lot, of strength to that axle.

Honestly, I'm not sure that's necessary. Normally, I'd agree. But he's got the drive sprockets located close to the frame points, and the wheel hubs aren't far off that. There isn't much stress on the central part of the axleshaft.

but there is, where is it going to bend first? at the frame or in the middle of the axle? naturally it will want to bend in half, if you ut a bearing in the center of it its going to take alot more of leverage to bend the axle at the frame with about 6 inches of leverage opposed to the whole width of the axle

Well- it's going to want to bend where the forces concentrate- at a leverage point. Generally, just outboard of the frame mounting point (bearing). Ask a guy that has snapped an axle (LOL).

If it were a go kart, or some other arrangement where the drive sprocket were located in the middle of a lot of unsupported axle, I would call it paramount.

But like anything else untried, this will reveal itself.

Mechanically, I'd say it's a sound idea. Since the hydro is not being overspeed on the input, it should not overheat. If you use the hydro to set your gearing, then use the throttle as a gas pedal, it shouldn't see a lot of strain. Driving, I'm not sure how it will run, be interesting to find out. Just don't slam the hydro control on and off, or fwd to reverse.

All i see is that if you put more blocks as close as possible to the rims then theres no need for a center support. hydros can pull a good abount so upping the gearing souldnt hurt it that much. I think going from max speed to stop (decending speed) will be intrusting.