McLaren Tracks and Power Question

[conc2steel]

I have a Bobcat running Pro-Track Rubber and recently installed a set of Bullman Flat Proof tires on it. The Bobcat already had spacers and the Bullman tires have the ability to mount "narrow" or wide. Narrow seems to be about the same as standard tires, wide adds about 6 inches in total width. I installed the tires in the wide configuration and did not remove the spacers, the Bobcat is extremly stable; however, I don't seem to have near the power with the skid steer as I had in the past. Before I remove the tires and traacks, I was wondering if anyone out there has had a similar experience and if the power issue is based on the tracks being too wide or if I've got a mechanical problem (it sucks to remove the tracks and sucks more to remove the tires)! Thanks for any recommendations.

 

[rock]

I have been running Bullman tires for about a year now and have no problem with the machine power or the tires. I love the tires. They saved me tons of flats and I don't think I'll ever go back to regular pneumatics again. Try removing your wheel spacers if you do not need them (Bullman wheels are off-set, so you may have enough clearance without the spacers). This will lower the weight a bit and may help regain some power. If you don't see any difference after you reduce the weight, you may have mechanical problem. Since Bobcat also sells over the tire tracks and flat proof tires, the machines are made to handle both of them.

 

[thetool]

I haven't seen it but this is what I've heard:
Steel over-the-tire tracks like Loegering allow a little bit of wheel spin inside the tracks, but rubber over-the-tire tracks don't and will cause binding of the axles. When using rubber over-the-tire tracks, the front drive chains in the chaincase must be removed or you risk snapping axles or breaking chains or the likes.
Anybody else heard this? Is it true? Could your loss of power be the drive train binding?

 

[m610]

I haven't seen it but this is what I've heard:
Steel over-the-tire tracks like Loegering allow a little bit of wheel spin inside the tracks, but rubber over-the-tire tracks don't and will cause binding of the axles. When using rubber over-the-tire tracks, the front drive chains in the chaincase must be removed or you risk snapping axles or breaking chains or the likes.
Anybody else heard this? Is it true? Could your loss of power be the drive train binding?

I don't know about other types, but I have used the rubber-band tracks on my M-610 for quite some time and never had chain issues. The trick is to make sure both tires are the same circumference and properly inflated. It's an old machine and I never noticed a loss of power on dirt, sand, grass, or other soft surfaces. On pavement it does rob turning power, that's it. As for snapping chains, that would only be a problem on a geared track system and frame that bolts on the axles. Otherwise it will wear sprockets and stretch the chain.

 

[skidsteer.ca]

I don't know about other types, but I have used the rubber-band tracks on my M-610 for quite some time and never had chain issues. The trick is to make sure both tires are the same circumference and properly inflated. It's an old machine and I never noticed a loss of power on dirt, sand, grass, or other soft surfaces. On pavement it does rob turning power, that's it. As for snapping chains, that would only be a problem on a geared track system and frame that bolts on the axles. Otherwise it will wear sprockets and stretch the chain.

The older goodyear track sytems ran the rubber tracks tight and even though they included 4 new tires and wheel designed for their tracks, they recommended unhooking the front drive chains.
However all the track since then us a run loose design that allows for minor differences in tire diameter by allowing the wheel to slip inside the tracks.
As for the track robbing power there should not be a noticable difference. Are you sure the perceived loss of power is not just a result of have more traction and that traction finding the limit of the motor and drives ability to turn the tires?
I have never used the rubber tracks, only steel, but I can tell you it takes 1/3 the power to spin just tires as it does to spin the tires and tracks. If the tracks are mounted too tight, this also will rob power as you will be forcing your tires to compress as they turn. You might want to check the manufactures instruction on this
I'd still recommend removing the wheel spacers if you do not need them as the wider you space your wheels out sideways, the more strees you put on you axel shafts and wheel bearings. Unless you really need the stability.
Ken

 

[Earthwerks Unlimited]

The older goodyear track sytems ran the rubber tracks tight and even though they included 4 new tires and wheel designed for their tracks, they recommended unhooking the front drive chains.
However all the track since then us a run loose design that allows for minor differences in tire diameter by allowing the wheel to slip inside the tracks.
As for the track robbing power there should not be a noticable difference. Are you sure the perceived loss of power is not just a result of have more traction and that traction finding the limit of the motor and drives ability to turn the tires?
I have never used the rubber tracks, only steel, but I can tell you it takes 1/3 the power to spin just tires as it does to spin the tires and tracks. If the tracks are mounted too tight, this also will rob power as you will be forcing your tires to compress as they turn. You might want to check the manufactures instruction on this
I'd still recommend removing the wheel spacers if you do not need them as the wider you space your wheels out sideways, the more strees you put on you axel shafts and wheel bearings. Unless you really need the stability.
Ken

I spoke to a former McLaren engineer who told me that right off the bat you will lose 30% power. And McLaren custoemr service themselves told me the same thing. The reason is quite simple: the tracks are made in a circle or ring. The ring wants to stay a ring, but when you put it on a machine you are stretching it to some extent but more importantly you are forcing it to conform to the shape of a belt by compressing it. This wouldn't be all that bad if you compressed it and left it alone. But you can't do that as it needs to move continually. And so you are continually compressing it and that takes power. Intertia is another concern--your machine now has to move that heavy rubber track through space to get traction and that takes power--a lot of power. It's sort of like putting big, oversize tires on a pickup that wasn't made to handle them--it affects the intial takeoff and also the braking trying to first get the tire going the trying to stop it. And the other reason is you are effectively making the tires larger or taller by adding the thickness of the track to the diameter---changes the gear ratio, just like on a truck. And that robs power too.

 

[mclarenusa.com]

I spoke to a former McLaren engineer who told me that right off the bat you will lose 30% power. And McLaren custoemr service themselves told me the same thing. The reason is quite simple: the tracks are made in a circle or ring. The ring wants to stay a ring, but when you put it on a machine you are stretching it to some extent but more importantly you are forcing it to conform to the shape of a belt by compressing it. This wouldn't be all that bad if you compressed it and left it alone. But you can't do that as it needs to move continually. And so you are continually compressing it and that takes power. Intertia is another concern--your machine now has to move that heavy rubber track through space to get traction and that takes power--a lot of power. It's sort of like putting big, oversize tires on a pickup that wasn't made to handle them--it affects the intial takeoff and also the braking trying to first get the tire going the trying to stop it. And the other reason is you are effectively making the tires larger or taller by adding the thickness of the track to the diameter---changes the gear ratio, just like on a truck. And that robs power too.

Hi guys,

Just wanted to add some comments.

Our over the tire tracks are made from individual track sections which are connected with dogbone links and carriages bolts. These track sections can have interchangeable shoes either rubber for Protrac Rubber OTT or steel for Magnum OTT or it can be the traditional cross bar type sections, Protrac Diamond OTT.

Protrac Rubber is a "run loose system" just like a regular steel OTT track. However, the weight of the sections sag down over the top in between the tires creating more surface contact between the tire and the track. The loose running style combined with heavier sections, and tread bars on the inside helps prevent the tires from slipping inside. Even though this system is heavier it doesn't mean more power loss. If a lighter pair of tracks need to be mounted tightly around the tires to prevent slipping you will also have power loss from the added friction and force needed to rotate the system. Moreover, you really lose power on a tight running system if mud and debris builds up on the tracks.

Usually in a wet condition, we are wasting the machine's power by spinning our tires instead of digging. Even though it provides more power to the wheels, more fuel and time is waste when you compare the performance with tracks.

With any type of track system you will encounter some power loss, but if you have a good track system that power loss should contribute to more traction and floatation. As a result, if the power loss contributes to greater performance gains and productivity on wet jobs, then tracks are worth the power loss (which is why most people look for tracks in the first place).

I hope this helped clarify some concerns. Feel free to visit our website for more information: www.mclarenusa.com