new mod.

[BobRip]

Sounds like you need to call Char-Lynn again. I think this is a normal use, so it's probably OK. I would call just to make sure. You probably know more about hydraulics than most mechanical engineers. A degree is OK, but it's just a start.

 

[KentT]

I still don't have a quote back on the Char-Lynn Model S motors that I spec'ed-- the distributor is waiting to hear back from the factory.

But I do have a quote back on the White Model WR motors, which is one step up from the RS series that's on it. I wanted something to compare with the Char-Lynn S model.

The WR is a roller stator and not a geroler, so it is not quite as efficient as the Char-Lynn. The possible advantage of the WR is that it is only 4" wide and would fit in the square hole of the PT's body with much less grinding required than the Char-Lynn. (In comparison, the current RS model is 3.5" wide). The WR is also a bit longer than the Char-Lynn S models or the current White RS. The model I spec'd is 7.9" long, so it would need to stick back inside the body of the PT almost 2 inches.

I spec'd out a 19.8ci (they jump from 14.4ci to 19.8ci with nothing in between), with a 1" tapered shaft, standard 4-bolt mounting and 1/2" SAE ports. (The WR comes with high-pressure seals standard.) This size WR is only rated for 1250 PSI continuous at 4 gpm (at higher gpm flows it is rated for 1500 PSI continuous), but 1750 PSI intermittent and 2500 PSI peak. This 1250 rating at lower flows is a bit of a concern but I'm not sure it's a "disqualifier" given the unknowns of the tram-pump's PSI output.

Here's how this 19.8ci WR model compares to the current 12.5ci RS model and the 18.2ci Char-Lynn Model s:

At 2gpm flow and 1500 PSI:
old = 2642 in lb torque, 23 RPM
S = 4143 in lb torque, 5 RPM
WR = 3944 in lb torque, 19 RPM

at 4 gpm flow and 1500 PSI:
old = 2641 in lb torque, 60 RPM
S = 4345 in lb torque, 35 RPM
WR = 4114 in lb torque, 39 RPM

at 6 gpm flow and 1500 PSI:
old = 2634 in lb torque, 96 RPM
S = 4070 in lb torque, 60 RPM
WR = 4103 in lb torque, 59 RPM

at 8 gpm flow (max) and 1500 PSI:
old = 2621 in lb torque, 133 RPM
S = 4020 in lb torque, 87 RPM
WR = 4037 in lb torque, 81 RPM

-----------------------------

at 1000 PSI and 2gpm flow:
old = 1809 in lb torque, 31 RPM
S = 2515 in lb torque, 15 RPM
WR = 2711 in lb torque, 20 RPM

at 1000 PSI and 4 gpm flow:
old = 1798 in lb torque, 68 RPM
S = 2897 in lb torque, 38 RPM
WR = 2813 in lb torque, 43 RPM

at 1000 PSI and 6 gpm flow:
old = 1721 in lb torque, 108 RPM
S = 2694 in lb torque, 67 RPM
WR = 2774 in lb torque, 65 RPM

at 1000 PSI and 8 gpm flow:
old = 1697 in lb torque, 144 RPM
S = 2516 in lb torque, 94 RPM
WR = 2701 in lb torque, 88 RPM

The quote I got was $312 each -- not bad, but I want to wait on the Char-Lynn quote before making a final decision. There's also the issue of a 8-9 week lead time from the factory on this WR quote.

 

[duane]

Kent,

Call Terry at Power trac to find out what the tram pump safety relief valves are set at. If you look at the end of the tram pump, you will two large hex looking type nuts. These are the relief valve catridges. One for each circuit (ie: forward and backward)

Duane

 

[johara1]

MR,that wheel motor it the newer stile square back without a case drain?mine are the older ones with a case drain made by danfoss. the motors you have had more torque than the older ones........jim

 

[johara1]

KentT,cutting the hole is a walk in the park,just put a piece of wood in back of it to keep from cutting something you don't want to.the wait will be worth it!!!.........jim

 

[J_J]

Bob, I'm assuming (you know what that means, right ) that the current system -- with two series circuits -- is likely limited by relief valves to 1500 PSI total. Without that pressure drop from series circuits, the system would go to 3000 PSI, theoretically, but that is limited by the relief valves. That was the foundation of the whole "Stray mod" concept. But, these White wheel motors couldn't stand those types of pressures.

It would certainly be nice to know the specs on the tram pump...

Kent, I believe that the tram pump is in the 3000 psi range, and the wheel motors also are 3000 psi motors. Most of the other hydro-stat pumps I have seen are in the 3000 psi and and greater. If I remember right, Pt told me that the relief valves on the wheel motors were set to 2750 psi. I believe that each wheel motor will see close to 3000 psi , or the relief valve setting, and that might be adjustable, when maxed out, as when trying to push against an immovable object, or the tires will spin.

 

[KentT]

Kent, I believe that the tram pump is in the 3000 psi range, and the wheel motors also are 3000 psi motors. Most of the other hydro-stat pumps I have seen are in the 3000 psi and and greater. If I remember right, Pt told me that the relief valves on the wheel motors were set to 2750 psi. I believe that each wheel motor will see close to 3000 psi , or the relief valve setting, and that might be adjustable, when maxed out, as when trying to push against an immovable object, or the tires will spin.

I also think the tram pump is a 3000 PSI, but I'm not sure. I called Tazewell and tried to get Terry to confirm it, but I couldn't get it out of him, saying I wanted to have my system checked to make sure it's working correctly before proceeding to upgrade it. Maybe someone else would have better luck. He wanted me to remove my tram pump and send it to them, and they'd do any needed tests and inspections and repairs, if needed. He discouraged me having it tested locally, saying that basically all I could check would be the charge pump pressure, which should be about 100 PSI cold and 90 PSI hot.

As I understand it, the "working pressure" on the wheel motors in these series circuits is 1/2 that -- if they were each hooked up independently on their own circuit (i.e. parallel circuits) then they'd each be subject to the full 3000 PSI. However, as plumbed, the line to the first motor in the circuit, and consequently the inlet on the first wheel motor would be at 3000 PSI. These White RS series wheel motors that are on it now aren't even rated for 3000 PSI -- they're 1500 PSI continuous, 1750 PSI intermittent, and 2250 PSI maximum.

Meanwhile, I got the first Char-Lynn quote back for 18.2ci S series motors that I spec'd out (as described above, with high-pressure seals and low-speed valving). The quote was $387 each, with a 3-4 week lead time for the factory to build them.

While I was waiting on that quote and trying to confirm what the PSI in the circuit was, yesterday I went to a different distributor and asked for a quote on the 22.7ci S series motor (the largest one available) with the same options as the 18.2ci one above. I figured this would give me somewhat of a price comparison, and the specs on that motor are intruiging to me.

At 2gpm flow and 1500 PSI:
old 12.5ci = 2642 in lb torque, 23 RPM
S 18.2ci = 4143 in lb torque, 5 RPM
S 22.7ci = 4599 in lb torque, 11 RPM
WR 19.8ci = 3944 in lb torque, 19 RPM

at 4 gpm flow and 1500 PSI:
old 12.5ci = 2641 in lb torque, 60 RPM
S 18.2 ci = 4345 in lb torque, 35 RPM
S 22.7ci = 5200 in lb torque, 32 RPM
WR 19.8ci = 4114 in lb torque, 39 RPM

at 6 gpm flow and 1500 PSI:
old 12.5ci = 2634 in lb torque, 96 RPM
S 18.2ci = 4070 in lb torque, 60 RPM
S 22.7ci = 5117 in lb torque, 50 RPM
WR 19.8ci = 4103 in lb torque, 59 RPM

at 8 gpm flow (max) and 1500 PSI:
old 12.5ci = 2621 in lb torque, 133 RPM
S 18.2ci = 4020 in lb torque, 87 RPM
S 22.7ci = 5119 in lb torque, 74 RPM
WR 19.8ci = 4037 in lb torque, 81 RPM

-----------------------------

at 1000 PSI and 2gpm flow:
old 12.5ci = 1809 in lb torque, 31 RPM
S 18.2ci = 2515 in lb torque, 15 RPM
S 22.7ci = 3447 in lb torque, 15 RPM
WR 19.8ci = 2711 in lb torque, 20 RPM

at 1000 PSI and 4 gpm flow:
old 12.5ci = 1798 in lb torque, 68 RPM
S 18.2ci = 2897 in lb torque, 40 RPM
S 22.7ci = 3613 in lb torque, 38 RPM
WR 19.8ci = 2813 in lb torque, 43 RPM

at 1000 PSI and 6 gpm flow:
old 12.5ci = 1721 in lb torque, 108 RPM
S 18.2ci = 2694 in lb torque, 67 RPM
S 22.7ci = 3494 in lb torque, 58 RPM
WR 19.8ci = 2774 in lb torque, 65 RPM

at 1000 PSI and 8 gpm flow:
old 12.5ci = 1697 in lb torque, 144 RPM
S 18.2ci = 2516 in lb torque, 94 RPM
S 22.7ci = 3515 in lb torque, 78 RPM
WR 19.8ci = 2701 in lb torque, 88 RPM

The 22.7ci S series is only rated at 1300 continuous and 1500 PSI intermittent, versus 1500 PSI continuous and 1800 PSI intermittent for the 18.2ci. If I could confirm that the tram pump was operating at 2600 PSI or less, I'd be real tempted to go with the largest motor. Note that at 2 GPM it is faster than the smaller 18.2ci one at 1500 PSI and the same speed at 1000 PSI. At 4 GPM they're at almost the same speed -- it's only at the higher flows of 6 GPM and 8 GPM that it is significantly slower. Meanwhile, the largest motor is producing much more torque -- over 1000 in lbs more than the 19.2ci version in some ranges... it literally doubles the torque produced by my stock wheel motors. By my calculations, these would push the PT at about 5.5 MPH at full throttle, full treadle -- assuming 80 RPM wheel motor speed, based on 8 GPM flow and PSI of 600 or less, where it is still producing more torque than my stock wheel motors. If that speed proved to be too slow, moving up from 23" to 26" tires would speed it up to about 6.2 MPH -- again, assuming 80 RPM and 8 GPM. In comparison, the smaller 18.2 ci S series should push the PT at nearly 7 MPH (6.84) MPH, assuming 100 RPM and 8 GPM flow.

But, since the larger wheel motors are only rated for 1300 PSI continuous, I'm reluctant to use them since I can't confirm the tram pump's PSI output. Similarly, the 19.8ci White WR series motors outperforms the 18.2ci Char-Lynn S series motor at 1000 PSI in most flow ranges, but not at higher pressures. That White motor, though, is rated at only intermittent use at 2 GPM and 1500 PSI -- which seems to me where you want to be able to use the full pressure potential (i.e. torque) of the wheel motor. I will wait to see the final Char-Lynn price quote for the largest motors, though, before I pull the trigger -- even though the quoted $387 price seems fair enough for a special order item (with options), when compared to johari's $380 price. Should this other distributor come back with a significantly lower price for the largest motor (with the same options) then I'll have them quote me the 18.2ci ones...

Meanwhile, I have to wonder how the low speed valving option I specified will improve the performance of the 18.2 ci motor at lower GPM rates, such as 2 GPM especially. It's hard to understand how the "standard" larger 22.7ci motor can both turn faster and generate far more torque at those low flows. This option could even impact RPMs at the higher GPM rates if it does improve the efficiency of the motors at under 200 RPM, as claimed...

 

[Bob999]

I'm reluctant to use them since I can't confirm the tram pump's PSI output.

You could plumb a pressure guage into one of the wheel motor circuits and monitor the pressure while operating the tractor--it would give you real world pressures under your operating conditions.

 

[J_J]

Kent, Check out those Char-Lynn wheel motors, 105-1006, and 105-1007.
They sound like what you want, but they aren't cheap. Rpm's of 168, 133

 

[KentT]

Kent, Check out those Char-Lynn wheel motors, 105-1006, and 105-1007.
They sound like what you want, but they aren't cheap. Rpm's of 168, 133

JJ,

To use those 2000 series motors I'd have to have new "mounting boxes" made and cut the old ones off. I'd also have to get new 1.25" wheel hubs.

Those are some nice specs, though...

 

[KentT]

You could plumb a pressure guage into one of the wheel motor circuits and monitor the pressure while operating the tractor--it would give you real world pressures under your operating conditions.

Yes, or just plan on running it at 3/4 throttle all the time so I wouldn't have to worry about it generating too high of PSI...

Actually, that's about where I leave the throttle set most of the time, if I'm not climbing hills or using the mower....

 

[BobRip]

Yes, or just plan on running it at 3/4 throttle all the time so I wouldn't have to worry about it generating too high of PSI...

Actually, that's about where I leave the throttle set most of the time, if I'm not climbing hills or using the mower....

KentT, I think the pressure would only be 3000 PSI for the extreme situations. Pushing into dirt and almost stalled or climbing a steep hill. This would probably be classified as peak pressure. While driving along, I would guess that it is much less. IMHO.

 

[BobRip]

case drains do many things(1)take any metal out of the motor without going through the rest.(2)cooling effect.(3)they are required on wheelmotors above 1500.also you gain a test port to know the condition of them.
the wheelmotors pt. uses are gerotor type, the s series are geroler,this have a lot more low end torque and start up torque........jim

SInce the geroler has more low end torque, eqaul displacement motors as compares to gerotor should have more low end torque. So would it be OK to use geroler motors of the same displacement and you would have the torque and the speed. Is my assumption here valid?

 

[KentT]

SInce the geroler has more low end torque, eqaul displacement motors as compares to gerotor should have more low end torque. So would it be OK to use geroler motors of the same displacement and you would have the torque and the speed. Is my assumption here valid?

Bob,

Neither the Char-Lynn S series geroler nor the White WR series geroter come in exactly the same size (12.5 ci) as the White RS series geroter that I have on there now. However, there's sizes that are fairly close. Since I have the catalogs on hand and the comparison charts set up, here's what they look like for the size closest to stock, yet larger -- I can't see you wanting to lose torque and gain speed by going smaller. I can only do a direct comparison at the 1000 PSI level, since the charts use different increments. But, it should give you some idea:

at 1000 PSI and 2gpm flow:
old RS 12.5ci = 1809 in lb torque, 31 RPM
S 13.7 ci = 1884 in lb torque, 23 RPM
WR 14.4 ci = 1979 in lb torque, 26 RPM

at 1000 PSI and 4 gpm flow:
old RS 12.5ci = 1798 in lb torque, 68 RPM
S 13.7 ci = 2103 in lb torque, 57 RPM
WR 14.4 ci = 2062 in lb torque, 56 RPM

at 1000 PSI and 6 gpm flow:
old RS 12.5ci = 1721 in lb torque, 108 RPM
S 13.7 ci = 2079 in lb torque, 91 RPM
WR 14.4 ci = 2010 in lb torque, 88 RPM

at 1000 PSI and 8 gpm flow:
old RS 12.5ci = 1697 in lb torque, 144 RPM
S 13.7 ci = 2131 in lb torque, 125 RPM
WR 14.4 ci = 1952 in lb torque, 115 RPM

At 2 GPM flows, these Charl-Lynn S series geroler motors don't seem to perform quite as well, and don't produce the RPMs of a geroter, though they produce good torque. But at 4 GPM (half-treadle)and above, they outperform them in producing both torque and RPM. At 6 GPM and higher, they produce more torque than the larger WR geroter motors, in addition to producing more RPM (which would be expected).

Here's the S series performance at higher PSI ratings. (Too bad the manufacturers don't provide their data in the same increments to facilitate comparisons -- but I suspect that is interntional.)

at 2gpm flow:
old RS 12.5ci at 1500 PSI = 2642 in lb torque, 23 RPM
S 13.7 ci at 1400 PSI = 2787 in lb torque, 16 RPM
WR 14.4 ci at 1500 PSI = 2894 in lb torque, 24 RPM

at 4 gpm flow:
old RS 12.5ci at 1500 PSI = 2641 in lb torque, 60 RPM
S 13.7 ci at 1400 PSI = 2992 in lb torque, 49 RPM
WR 14.4 ci at 1500 PSI= 3063 in lb torque, 50 RPM

at 6 gpm flow:
old RS 12.5ci at 1500 PSI = 2634 in lb torque, 96 RPM
S 13.7 ci at 1400 PSI = 2923 in lb torque, 83 RPM
WR 14.4 ci at 1500 PSI = 3028 in lb torque, 81 RPM

at 8 gpm flow:
old RS 12.5ci at 1500 PSI = 2621 in lb torque, 133 RPM
S 13.7 ci at 1400 PSI = 3017 in lb torque, 116 RPM
WR 14.4 ci at 1500 PSI = 2973 in lb torque, 111 RPM

While these are not direct comparisons (1400 PSI for the S series geroler vs 1500 PSI for the geroters), they should give you a sense of the difference performance levels and curves. Again, at 2 GPM flow the geroler doesn't perform as well as the geroters in producing RPM, but it produces good torque at a lower PSI. The larger White WR moter actually produces more RPM at 2 GPM than the smaller S-series geroler. At 4 GPM and above it's about the same as the larger WR geroter in both RPM and torque, though it's at 100 PSI less. At 8 GPM it is actually producing more RPM (expected, because of smaller displacement) but also more torque than the larger geroter, despite running at 100 PSI less.

Again it seems that the geroler is not as efficient at 2 GPM flow (at least without the Low Speed Valving option) in producing RPM, but it still produces good torque. At 4 GPM and above, it clearly outperforms the gyroters in both torque and RPM. It outperforms the stock, smaller 12.5ci RS series gyroters in torque at all flows, with 100 PSI less, yet it obviously cannot match the RPMs.

What I don't know is how the Low Speed Valving option that I specified will impact these low flow numbers. I assume it will help them somewhat, since it optimizes the motor for operation under 200 RPM, but I can't quantify that...

It seems the 13.7ci S series geroler would produce a noticeable improvement in torque at all speed and flow ranges, yet the difference is most noticeable at half-treadle and above, yielding higher GPM flows. Too bad the S-series doesn't come in a size between the 13.7 ci and 18.2 ci -- something along the line of a 15.3ci or 15.9 ci. Those sizes would yield a siginificant improvement in torque that would not require sacrificing as much top end speed as the large 18.2 ci ones does. Yet, they'd be an easier conversion, done by enlarging the hole in the body as johari has done.

Note that the Char-Lynn W series gyroler comes in a 15.3 ci displacement, with all the innovations of the new S series, but it is a "short, stubby" motor with 1.25" tapered shafts that would require making new wheel boxes and replacing the wheel hubs. The White geroter motors come in both a 15.5 ci for the RS series (the series mine has now, with 1" shafts) and 15.9 ci for the "short, stubby" CE series with 1.25" shafts. I think the newer PT-425s have either the 15.9 ci White CE geroter (most likely) or the 15.3 ci W series Char-Lynn. Either of these would yield the "about 40% increase in torque" that we hear, but they'd also require the new style, larger "wheel boxes" to mount them.

If someone wanted to build the new style wheel boxes and buy 1.25" wheel hubs, the Char-Lynn 15.3 ci W-series geroler with parking brakes on Surplus Center for $329.95 would be a GREAT conversion...

Hope this has been of some value...

 

[BobRip]

KentT, Wow! Thanks for the detailed answer. I did not realize this would put you to so much work. I would want at least a 50% increase in wheel torque and would give up up to 3 MPH to get it. I think that the main torque that I really care about is zero speed. Do you have data on that? Let not over analyze this though.

Do you see any issues with the wheel boxes handling the extra torque? I think not since they handle the weight of the machine.

Is there any trash in the new motors that could get into the pump? I understand that this type of pump is very sensitive to dirt.

I hope I am not asking too many questions. Feel free to tell me if I am.

 

[KentT]

KentT, Wow! Thanks for the detailed answer. I did not realize this would put you to so much work. I would want at least a 50% increase in wheel torque and would give up up to 3 MPH to get it. I think that the main torque that I really care about is zero speed. Do you have data on that? Let not over analyze this though.

Do you see any issues with the wheel boxes handling the extra torque? I think not since they handle the weight of the machine.

Is there any trash in the new motors that could get into the pump? I understand that this type of pump is very sensitive to dirt.

I hope I am not asking too many questions. Feel free to tell me if I am.

If you want a 50% increase in torque, then the Char-Lynn S-series 18.2 ci geroler seems to be the way to go -- like johari did. Here's the improvements over the stock 12.5 ci White geroters:

at 1000 PSI and 2gpm flow: 56%
at 1000 PSI and 4 gpm flow: 64.5%
at 1000 PSI and 6 gpm flow: 54.5%
at 1000 PSI and 8 gpm flow: 53.4%

at 1500 PSI and 2 gpm flow: 39%
at 1500 PSI and 4 gpm flow: 61%
at 1500 PSI and 6 gpm flow: 56.5%
at 1500 PSI and 8 gpm flow: 48%

The "sweet spot" appears to be 4-6 GPM flow. As I mentioned earlier, I calculated the 18.2ci would turn approximately 6.8 MPH at 100 RPM which it is rated for at 400 PSI. Since "cruising" you'd likely have more PSI than 400 -- perhaps 800, which is 96 RPM, then you'd be slightly below that 6.8 MPH... let's say 6.5 MPH to be safe.

The Char-Lynn specs don't provide anything close to "0" though the White motors show specs down to .5 GPM. Let's assume it will take 600 to 800 PSI to get the tractor moving -- not pushing into dirt or anything. The 18.2ci motor shows 1711 in lbs of torque at 2 GPM and 600 PSI, and 2210 in lbs at 2 GPM and 800 PSI. In comparison, the 12.5 ci White RS motors on it are rated at 927 in lbs of torque at 500 PSI and 1386 in lbs at 750 PSI. Though different increments, you can see the larger geroler puts out much more torque at 600 PSI than the stock geroters put out at 750 PSI. I think the difference would be dramatic, starting from a dead stop and accelerating, much less pushing into a pile of dirt...

I don't think the stock wheel boxes will have any problems with the torque. I think you'd either spin the tires or stall the engine long before you'd over-stress the boxes the wheel motors are mounted in.

I don't know what contaminents may come with new wheel motors, but I'd imagine they would be VERY clean, and all ports plugged to prevent anything getting in there...

They do caution you to run the new wheel motors for approximately 1 hour at 30% of rated pressure to break them in, before going to full load, and to make sure they are filled with fluid before putting any load on the system.

 

[johara1]

KentT, they are clean ,i also cleaned the tank.i put in new oil and filter and ran it for a few hours and changed the filter again.
yes it will spin the tires! and for the first time it will spin all four......jim

 

[KentT]

Just a brief update. I'm still waiting on the price quote on the 22.7ci Char-Lynn S-series. One distributor is telling me that they have never made the 22.7ci motor with the options I spec'd -- so I have them researching if they've made them with everything but the high-pressure seals. The standard seals are rated to 1500 PSI, but because the front wheel motors would be getting the full input pressure, I spec'd the high pressure ones just to be safe...

Meanwhile, I got another price quote back on the 19.8ci White WR-series geroter motor. These are $90 less than the initial 18.2ci Char-Lynn quote I've received -- $296.32 each in quanties 1-4, compared to $387 each for the Char-Lynn. This quote is almost $100 less than the previous WR quote I received... It caught my attention! (Seems the White factory had referred this distributor to me in response to me asking them what larger motor would fit -- the call came out of the blue!)

The $360 difference in cost to upgrade has me seriously considering the White WR. Note that it is 4" wide and 7.9" long. It should require quite a bit less cutting/grinding than the Char-Lynn also, since the square hole in the body is 4" wide -- it just sticks almost an inch farther back into the body...

I can get a MUCH better price break if I buy 5 or more -- down to $210.75 each, plus shipping. Anyone want to do a "group purchase?" That would get the cost of the upgrade down to $843.00 plus shipping -- almost 1/2 that of the Char-Lynn motors. Note that I've posted the performance specs in my comparisons above. It compares pretty well with the 18.2ci Char-Lynn...

As it is, it would be cheaper for me to buy a spare than just four... go figure!

5 of these WR 19.8ci geroter motors for $1053.75
Only 4 of those same motors for $1185
4 Char-Lynn 18.2ci geroller motors for $1548

Makes me wonder how much the difference in the geroler might be...

 

[KentT]

Johari,

This good price on the White motors does raise a question...

Do you think there's enough room inside the engine compartment to wiggle in a motor that's over an inch longer than the Char-Lynn motors you just installed?

The White 19.8ci WR is rectangular, and 3.1" tall, 4" wide (would likely still require some grinding for clearance) and 7.89" long. In comparison, the 18.2ci Char-Lynn S is round and 4.24" in diameter and only 6.66" long.

Do you think there is enough room by the engine to "thread in" a 1-1/4" longer motor into the square hole in the body so that the shaft clears the mounting box, and then slide it back out to bolt up to the mount? Did you notice how much clearance you had? Note that I'm talking 1.25" longer than the Char-Lynn you installed -- and almost 2" longer than my stock 12.5ci RS motors.

I guess if it's too tight one option would be to unbolt the motor and slide it to the side far enough to do so -- but that would be a PITA...

Thanks!

 

[KentT]

Well, since White uses the same increments on the RS & WR performance charts, I can do "head-to-head" comparisons on these two motors -- though the numbers at very small GPM flows and very low pressure look at bit flakey (due to rounding error, I'd guess). Overall, it looks like the larger motor gives a bit over 50% more torque at almost 40% less speed.

I didn't bother to do the % calculations at the smaller PSI which you'd likely never see in use. However, I can see the low GPM numbers being meaningful, as you accelerate from a stop, or push your way into a pile of dirt. The RPMs at low GPMs look flakey though...

Overall, a pretty good tradeoff in speed for torque, for my purposes. Top speed should be right around 6 MPH (6.1 assuming 90 RPM), with well over 50% -- maybe even an average 60% -- more torque beween 1/2 and 2/3 treadle...
------------------------------------------

At 250 PSI & .5 gpm -- White 12.5ci RS -vs- White 19.8ci WR
414 in lbs torque & 8 RPM -vs- 630 in lbs torque & 7 RPM

At 250 PSI & 1.0 gpm -- White 12.5ci RS -vs- White 19.8ci WR
432 in lbs torque & 17 RPM -vs- 661 in lbs torque & 11 RPM

At 250 PSI & 2.0 gpm -- White 12.5ci RS -vs- White 19.8ci WR
416 in lbs torque & 36 RPM -vs- 684 in lbs torque & 22 RPM

At 250 PSI & 4.0 gpm -- White 12.5ci RS -vs- White 19.8ci WR
380 in lbs torque & 73 RPM -vs- 680 in lbs torque & 46 RPM
------------------------------------------------------------------------
At 500 PSI & .5 gpm -- White 12.5ci RS -vs- White 19.8ci WR
846 in lbs torque & 7 RPM -vs- 1250 in lbs torque (47.8% More) & 5 RPM (28.6% less)

At 500 PSI & 1 gpm -- White 12.5ci RS -vs- White 19.8ci WR
865 in lbs torque & 17 RPM -vs- 1314 in lbs torque (51.9% more) & 11 RPM (35.3% less)

At 500 PSI & 2 gpm -- White 12.5ci RS -vs- White 19.8ci WR
927 in lbs torque & 36 RPM -vs- 1385 in lbs torque (49.4% more) & 22 RPM (38.8% less)

At 500 PSI & 4 gpm -- White 12.5ci RS -vs- White 19.8ci WR
849 in lbs torque & 73 RPM -vs- 1402 in lbs torque (65.1% more) & 45 RPM (38.4% less)

At 500 PSI & 6 gpm -- White 12.5ci RS -vs- White 19.8ci WR
795 in lbs torque & 110 RPM -vs- 1353 in lbs torque (70.1% more) & 68 RPM (38.2% less)

At 500 PSI & 8 gpm -- White 12.5ci RS -vs- White 19.8ci WR
734 in lbs torque & 147 RPM -vs- 1278 in lbs torque (74.1% more) & 92 RPM (37.4% less)

------------------------------------------------------------------------------------
At 750 PSI & .5 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1250 in lbs torque & 6 RPM -vs- 1855 in lbs torque (48.4% more) & 5 RPM (16.6% less)

At 750 PSI & 1 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1360 in lbs torque & 15 RPM -vs- 1952 in lbs torque (43.5% more) & 10 RPM (33.3% less)

At 750 PSI & 2 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1386 in lbs torque & 34 RPM -vs- 2066 in lbs torque (49.1% more) & 21 RPM (38.2% less)

At 750 PSI & 4 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1349 in lbs torque & 72 RPM -vs- 2116 in lbs torque (56.9% more) & 44 RPM (38.8% less)

At 750 PSI & 6 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1322 in lbs torque & 110 RPM -vs- 2071 in lbs torque (56.7% more) & 67 RPM (39.1% less)

At 750 PSI & 8 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1228 in lbs torque & 146 RPM -vs- 1996 in lbs torque (62.5% more) & 90 RPM (38.4% less)

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At 1000 PSI & .5 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1621 in lbs torque & 5 RPM -vs- 2454 in lbs torque (51.3% more) & 4 RPM (20% less)

At 1000 PSI & 1 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1732 in lbs torque & 14 RPM -vs- 2576 in lbs torque (48.7% more) & 10 RPM (28.6% less)

At 1000 PSI & 2 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1809 in lbs torque & 31 RPM -vs- 2711 in lbs torque (49.9% more) & 20 RPM (35.5% less)

At 1000 PSI & 4 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1798 in lbs torque & 68 RPM -vs- 2813 in lbs torque (56.4% more) & 43 RPM (36.8% less)

At 1000 PSI & 6 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1721 in lbs torque & 106 RPM -vs- 2774 in lbs torque (61.2% more) & 65 RPM (38.7% less)

At 1000 PSI & 8 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1697 in lbs torque &144 RPM -vs- 2701 in lbs torque (59.2% more) & 88 RPM (38.9% less)

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At 1250 PSI & .5 gpm -- White 12.5ci RS -vs- White 19.8ci WR
1983 in lbs torque & 3 RPM -vs- 3043 in lbs torque (53.4% more) & 4 RPM (33.3% more)

At 1250 PSI & 1 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2136 in lbs torque & 11 RPM -vs- 3168 in lbs torque (48.3% more) & 9 RPM (18.2% less)

At 1250 PSI & 2 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2166 in lbs torque & 29 RPM -vs- 3340 in lbs torque (54.2% more) & 20 RPM (45% less)

At 1250 PSI & 4 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2204 in lbs torque & 65 RPM -vs- 3484 in lbs torque (58.2% more) & 41 RPM (36.9% less)

At 1250 PSI & 6 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2207 in lbs torque & 103 RPM -vs- 3454 in lbs torque (56.5% more) & 62 RPM (47.5% less)

At 1250 PSI & 8 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2102 in lbs torque & 142 RPM -vs- 3381 in lbs torque (60.8% more) & 85 RPM (40.1% less)
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At 1500 PSI & 1 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2517 in lbs torque & 9 RPM -vs- 3765 in lbs torque (49.6% more) & 8 RPM (11.1% less)

At 1500 PSI & 2 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2642 in lbs torque & 23 RPM -vs- 3944 in lbs torque (49.3% more) & 19 RPM (17.4% less)

At 1500 PSI & 4 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2641 in lbs torque & 60 RPM -vs- 4114 in lbs torque (55.6% more) & 39 RPM (35% less)

At 1500 PSI & 6 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2634 in lbs torque & 96 RPM -vs- 4103 in lbs torque (55.8% more) & 59 RPM (38.5% less)

At 1500 PSI & 8 gpm -- White 12.5ci RS -vs- White 19.8ci WR
2621 in lbs torque & 133 RPM -vs- 4037 in lbs torque (54% more) & 81 RPM (39.1% less)