Belted track gear reduction ?

[rodp]

First off, this could go on a while as I just don't get it. How do belted tracks give a gear reduction, the crossers travel at the same speed as the tyre periphery, IE, road speed ? Or have I misread posts and they don't give a gear reduction.

Can someone explain this in simpletons terms please?

[foxvalley]

First off, this could go on a while as I just don't get it. How do belted tracks give a gear reduction, the crossers travel at the same speed as the tyre periphery, IE, road speed ? Or have I misread posts and they don't give a gear reduction.

Can someone explain this in simpletons terms please?

No gear reduction.

The argo admiral tranny has a high torque, low speed tranny available,this has a reduced gear. Not sure what posts you are referring to?

[rodp]

I'll try to find one post out.

[Buzz]

Not all belted tracks provide a gear reduction. A track whose crossers are connected to an "elevated belt" provides gear reduction (escargo and those modeled after it...chanel tracks, adair classic tracks).
Think of it like this: the crossers do drive the belting, but the belting determines your axle speed. The overall length of the track itself (determined by the belting) determines the final drive ratio. An elevated belt track is "shorter" overall when laid flat on the floor next to a standard track that has it's belting at the tire tread surface. The belting can be thought of as the "chain" and the tires can be thought of as "sprockets". Or you could think of the tires as "pulleys" and the track belting is the "belt." This belt rides in further toward the "center" of the pulley or on a smaller "sprocket" in relation to the tire tread and the axle. The axles still turn the same, but they have to drive a smaller "sprocket" or "pulley". But remember the overall track length of this design is almost 2 feet shorter than for instance an argo rubber track. The belting length determines drive ratio.
Now all 4 tires are wrapped by the elevated belt and you would think that they are all driven at the same speed. This "would" be true except one interesting thing happens....as the track crossers make their way around the front/rear tires, they "splay-out" because they are not connected at the tire-tread location and can move closer or farther apart in relation to one another. In our case, they move "farther" apart from one another at the tire-tread (driven by the tire), while at the belting (where they connect) they stay in fixed-relation to one another. It takes less belting distance (even though the crossers are connected in fixed positions here) to cover the tire circumfrence. So, for a given axle speed (driven by the front/rear)......a slower track speed (belting speed) will be seen over the center axles. If all drive chains are left connected, the center tires simply rotate faster than the track crossers moving over them. The only additional "load" that the machine sees is that of the vehicle weight over the center axles as these tires will need to slip......not a problem as there is not constant high-friction contact, but a tire without lug "troughs" helps, as do track tuners for less load and better mileage. They're not needed (the individual smooth crossers allow for easy slipping), but I like the way the machines feel with them on.
The description always gets wordy....sorry

[rodp]

Thanks Buzz, I had got it about the different speeds relevant to front / rear and centre tyres . I just thought I had missed something as I assumed that forcing the centre tyres to spin wouldn't be a design feature. I suppose though, if you need tracks the conditions allow for relatively low friction anyway.
I was trying to figure out how it all worked and kept all wheels the same relative to track speed. Obviously I couldn't figure this out because it's impossible

[Buzz]

yeah, it is a bit confusing. I initially got the gear-reduction part, but the differing-wheel speeds is what took a while to understand. The elevated belt provides gear reduction, the "splaying-out" of the crossers at the tire tread is what effects the tire speed relative to the belting speed over different tires.
The tire slip happens, it's not a big deal as the track is a low-speed, high-grunt design anyway.

[Jetlee]

yeah, it is a bit confusing. I initially got the gear-reduction part, but the differing-wheel speeds is what took a while to understand. The elevated belt provides gear reduction, the "splaying-out" of the crossers at the tire tread is what effects the tire speed relative to the belting speed over different tires.
Stacking the crossers closer together lessens this, but a wider spacing just works better in every way. The tire slip happens, it's not a big deal as the track is a low-speed, high-grunt design anyway.

Would you be willing to share the optimal crosser spacing measurement? No problem if it's "classified" lol!!!

[Buzz]

Would you be willing to share the optimal crosser spacing measurement? No problem if it's "classified" lol!!!

Well, the optimal spacing (and crosser width) remains to be seen. Ultimately it's a balance between what is the most "aggressive" in grabbing traction, mud, and water...while still providing adequate tire coverage and track retention, but (so far) I personally prefer crosser spacing on 5" centers. I know that all-steel escargos are currently being made on 5" centers for what that's worth. You could argue that the ride is rougher, but this only happens on hard-pack. Where you really "need" the tracks, it's a non-issue altogether. I'm still experimenting and plan to try few different "body-shapes"....all interchangeable bolt-on crossers. I think with a wider spacing, and alternating body "profiles"....each crosser will cause less turbulence or disruption of the mud/water that the "next" crosser sees. It only makes sense that more of the crossers would then be able to get a better grab on -untouched- material.... which would make for a faster track in the water and a more agressive track all around. Mud-tires do this, and I have seen it in other track designs. But, this effect should be amplified when applied to the large vertical surface-area (paddle engagement) of an escargo-shaped crosser. I do know that this along with the ability to bolt on steel traction cleats makes for a light track that has no problems with traction. I am really hooked on the performance of these wide-body style crossers because of the sheer vertical surface area...paddle-track-like performance in the snow/mud. Throw in a wider belt (because the wider crosser-body can take it) and the track does even better. But......you have to be willing to run a wider- wheelbase. A lighter, hybrid version of this track (along with a set of track tuners) really brings machines that seem "underpowered" back to life. And, you get the performance of tracks too.....it's pretty cool.

[Obsessed]

Optimal track lug spacing is determined by grouser design and belt placement, in addition, the intended purpose of the track and the specific terrain requirement all contribute to the theory of perfect track pitch...it is impossible to choose just one number and refer to it as perfect...generally speaking, most atv tires are designed to repeat a pattern every 8 inches and approximatly 2 and one third inches is a pretty common lug spacing...typically wider track lug spacing results in lighter overall weight, and a lower cost track, but compromises overall durability, smooth ride, and unfortunatly allows larger objects to find their way into the track

tim

[rodp]

yeah, it is a bit confusing. I initially got the gear-reduction part, but the differing-wheel speeds is what took a while to understand. The elevated belt provides gear reduction, the "splaying-out" of the crossers at the tire tread is what effects the tire speed relative to the belting speed over different tires.
Stacking the crossers closer together lessens this, but a wider spacing just works better in every way. The tire slip happens, it's not a big deal as the track is a low-speed, high-grunt design anyway.

Does the belt elevation affect the relative speeds of centre wheels / tracks by much, are we talking big differences here ? I suppose I could work this out to be honest but I don't have a calculator to hand and it's first thing in the morning ................. I need more coffee.

[Buzz]

yes, the more belt elevation you have, the less belt speed (track speed) you will see for a given amount of tire rotation on the front/rear. If you leave the center axles chained up, the centers will also "slip" faster to match the front/rear. This will be progressively faster than the track speed rolling over the centers as you elevate the belt more and more. I suppose you could almost look at the sidewall of the tire, and if (lets say) the belting is elevated 3"......when running a 25" tire....then your tire diameter (on the front/rear...the drivers) is reduced by 3" on top + 3" on bottom (total of 6"). Your machine sees the front/rear tires as 19" diameter, while the track itself rolls over the centers as if they remained 25" diameter. If you disconnect the centers, you can see the centers roll "with" the track...much more slowly than the front/rears are driven. If they remained chained up, then the centers (25") will "peel-out" fast enough to match the axle speed of the front/rear (19").

[North Country Tough]

All I can say is coolany further reduction without having to go to the expense and bother of driveline change out the better.I cant say that I totally understand it but I never claimed to be the smartest man out there.And having this forum to draw from the wealth of info out there is great,I have inhabited this planet for a great number of years and not afraid to say that I still learn something every day,I know that the track debacle runs deep but the more input on all designs out there is much appreciated by me for sure,if every move I had made in my lifetime had of been the proper one I could afford to hire someone to sort this stuff out thanks for the ongoing info everybody. Cheers N.C.T

[Jetlee]

Thanks for the explanation guys.

[akranger72]

Hey Buzz just wondering if you have pics or could get a pic on here of say Argo or Mudd Ox rubber tracks laid out next to your UHMW tracks or your Escargo tracks just to show how much shorter and longer they are next to each other? This would help alot with some of the confusion about how the Adair classic tracks or your UHMW or Escargo tracks gear down an Argo or Mudd Ox running them.

[Buzz]

If I still had a pair over-the-tread tracks I would, sorry. It's in the neighborhood of (oh I don't know) probably 20 inches shorter if I had to ballpark it. An over the tread track probably uses 4-6 additonal crossers per side....not much. I was really looking forward to seeing your machine tracked-up akranger72....?