Custom transmission gears?

[Maxwell-8 4,357]

Has anyone made custom gears for a 8-speed transmission?

 

I have to drive 2-3 miles on a paved road to get to a propriety of ours. So I am looking for higher cruising speed in 3th gear.

It is currently pulley swapped. But that does mean a very high rpm on the input shaft of the transmission. What would be a safe rpm on that shaft?

 

I know a youtuber called "Studabaker" that made custom gears for his Cub cadet. ( Those tractors are shaft driven, so different gearing is the only way to increase road speed.)

 

Any tips on tools to cut gears? 

What about hardening of the gears? 

 

[ri702bill 8,550]

Max

Over the years at work, we had the occasional need to have specialized straight spur gears made to interact with a Customer's product during Testing.

 

Old School method used for the last 100 years was to have the teeth hobbed.  The center hole and keyway were machined first and used to fixture the blank. A single tooth profile was cut thru the stationary gear blank, the cutter returns, the blank is revolved to the angle of the next tooth, and so on. The gear blank had to be unhardened for this. After cutting, usually just the teeth would be induction hardened. Blanks may be stacked, but within space limits.

 

Modern method is to use a slightly larger disc that is already thru hardened to the desired level. A CNC Wire EDM Machine is used to cut all the features in the same setup. A small 3 to 4 MM hole is present in the blank so the .005" diameter wire can be fed thru to cut the internal features. For cutting the external tooth profile no hole is needed.

Benefits - thru hardened finished part. Blanks can be stacked to a height of roughly 4 inches and all cut at once. Reduced runout as all features are cut in the same setup.

The Electro Discharge Machining process is a chip less one, unlike hobbing. The surface finish from EDM is smoother - less gear noise...

 

Compound gears need to dealt with each individually.

Edited December 30, 2024 by ri702bill

[953 nut 56,046]

Larger rear tire diameter would help. 

[ri702bill 8,550]

2 hours ago, Maxwell-8 said:

higher cruising speed in 3th gear

 

And a bit more...

The shaft center distances are already defined in the Unidrive - and that sets the minor backlash between mating gears. Changing 3rd gear ratio may not be possible internally....

 

I agree that the taller tire would give a higher ground speed.....

[Handy Don 12,561]

17 minutes ago, ri702bill said:

The shaft center distances are already defined in the Unidrive

Bill, would it make sense to look a the Hi-Lo and convert it to Hi-Higher? That way the 1-2-3-R gears could remain as-is.

I know that Lo is 4:1 vs. Hi at 1:1, but I have no idea how that is accomplished! School me, please. 

Edited December 30, 2024 by Handy Don

[8ntruck 7,147]

2 hours ago, ri702bill said:

 

And a bit more...

The shaft center distances are already defined in the Unidrive - and that sets the minor backlash between mating gears. Changing 3rd gear ratio may not be possible internally....

 

I agree that the taller tire would give a higher ground speed.....

If you keep the total number of teeth on the new gear set the same as the old gear set, the shaft center distance does not change.

 

Example: old set maybe has a drive gear with 20 teeth and a driven gear with 60 teeth.  Total tooth count is 80.  Possible higher ratio replacement on the same shaft center would be 40 tooth drive and driven gears.  This would change a 3:1 ratio to a 1:1 ratio.

 

Exact numbers depend on what already exists.  Custom gears for sure - $$$.  Might have to mess with changes to the diametrical pitch and tooth form to get what you want as well. 

[ri702bill 8,550]

2 hours ago, Handy Don said:

Bill, would it make sense to look a the Hi-Lo and convert it to Hi-Higher? That way the 1-2-3-R gears could remain as-is.

I know that Lo is 4:1 vs. Hi at 1:1, but I have no idea how that is accomplished! School me, please. 

 

Don - Best to look at the 8 speed exploded drawing and the Tutorial for what happens when you shift the Hi-Lo lever into Low.

WH was NOT the first to add a selective 4:1 input reducer. Cub did so in the early 1960's as a bolt-on externally mounted speed reducer that interfaced with the input.

Just like the Hi-Lo lever on the WH 8 speed, you could choose...

[Handy Don 12,561]

Earlier post by @Handy Don:

would it make sense to look a the Hi-Lo and convert it to Hi-Higher? That way the 1-2-3-R gears could remain as-is.

I know that Lo is 4:1 vs. Hi at 1:1, but I have no idea how that is accomplished! Could 4:1 be re-geared to, say, 1:2 or even 1:3? School me, please. 

 

14 minutes ago, ri702bill said:

 

Don - Best to look at the 8 speed exploded drawing and the Tutorial for what happens when you shift the Hi-Lo lever into Low.

 

The only WH transaxle I’ve been into was for a hydro which had only reduction gearing and a differential.

Hoping someone whose hands and eyes have more experience than mine can weigh in. What say you @stevasaurus?

Edited December 30, 2024 by Handy Don

[Maxwell-8 4,357]

A LOT of  good info here, Thanks! 

I have a spare  transmission I am going to take apart and see what we can do.

 

The input bearing on a 8 speed is a 5/8x13/16x7/16 needle bearing. The smallest bearing on these transmissions. 

 

Stock it's running at 2250rpm

Would 5.000 rpm be okay? With my tires, stock gearing being 24.6 to 1, that would be 15 mph.

 

Most company's that sell this size bearing are saying a max rpm anywhere from 8.000 to 15.000rpm. 

[stevasaurus 22,901]

Well, I've read and re-read this thread so as to really understand what you guys are talking about.  You guys are above my pay-grade, but I do understand your thoughts getting into this.

   Here are my thoughts...all of the manual Wheel Horse transmissions are built with the same gear ratios for the forward gears in high range and the ones with just 3 speeds.  The cluster gear (I think) is the same gear for all of them and that is the gear that changes  the speed to the trans by changing position with different fork gears.  To do what is you guys a talking about, 1. recasting a cluster gear. 2. figureing out what kind of fork gear to match it with. 3. I bet there is not enough room in the case to do it, plus you would have to give up something you may not want to to get your top end. 4. None of this is cost effective.

   My solution...trailer the horse to where you want to go and use it for what it is intended.  Riding a Wheel Horse for 3 or 4 miles is not that much fun, when you think about it.

   My other thought is the rear end.  The Cub Cadet is a shaft driven tractor.  The Wheel Horse manual transmissions are a transmission with a rear end in the same case.  Changing the number of teeth on the large part of the mushroom gear to mesh with whatever number of teeth on the bull gear of the differential might be something for you guys to think about.

[Maxwell-8 4,357]

8 minutes ago, stevasaurus said:

My other thought is the rear end.  The Cub Cadet is a shaft driven tractor.  The Wheel Horse manual transmissions are a transmission with a rear end in the same case.  Changing the number of teeth on the large part of the mushroom gear to mesh with whatever number of teeth on the bull gear of the differential might be something for you guys to think about.

I believe the guy did just that on his cub cadet. Changing the final ratio. It would keep rpm's down on all the shafts expect the axles, which those bearing can easily handle a bit more rpm.

What is your thought on the input bearing max rpm? What is a speed that would still last? Changing to a sae 90 instead of a sae 140 when turning that fast?

[stevasaurus 22,901]

No, I do not think that is an option (input gear).  Do youself a favor...open up one of the transmissions and look at the videos I have on file.  See how all of this works and how much room you have in there.  Also, see that you have to give up space to try to fit somthing and how that would work.  I think you will see that using a trailer is going to be more cost effective and the horse will still function for what it is intended.  Open one up and see what you think.  

   One thing I have to say, as many of the different Wheel Horse transmissions that I have opened, I have always been in awe for the basic engeneering that is incorporated in these little guys.  To be able to exchange some parts and case halves throughout the different lives of these transmissions is remarkable engineering.  I have therefore addopted this belief...(DNFW)  Do Not F... With.  
 

[Maxwell-8 4,357]

I have rebuild 3 myself, 4th one is laying ready. They are just build simple yet strong.

I wouldn't consider these modification on anything but a WH transmission for that reason.

 

I know I am getting into the "get an ATV"-zone but that wouldn't be so challenging and fun. And I don't live in the USA were you can find them used for 600 dollars..

 

 

[Handy Don 12,561]

1 minute ago, Maxwell-8 said:

I have rebuild 3 myself, 4th one is laying ready.

When you get into the transaxle with an eye toward possible re-gearing, please start a thread with pictures and your thoughts.

 

@stevasaurus’s “leave well enough alone” mantra (I’ve substituted in the PG rated version) resonates with me, for sure. But it can be neat to consider going outside the lines and come up with new uses for things.

[Maxwell-8 4,357]

Looking at my pictures,  Changing the ratio of one gear is nearly impossible to get a decent increase in speed. 

The bull gear is interesting for a big speed increase, but probably at the cost of having a diff. 

The best route probably is changing the big gear driving the gear to the transmission and the gear that is driving it.  (the two gears that are the lowest in this picture.)

But it is tight too it looks like. 

 

 

Edited December 30, 2024 by Maxwell-8

[8ntruck 7,147]

  the Allis Chalmers B-110  I picked up this summer has the diff built into one of the hubs.  Might be an option - possible packaging issues, though.

[mrc 851]

hello Maxwell-8,

  

  in your original post you say "it has already been pulley swapped"    do you mean you replaced the 4 inch engine drive pulley with a 5.25 inch hydro pulley?     also please remember that the brakes are not the best on a wh.  so if you are going faster your stop time/distance will increase

 

regards

mike

[kpinnc 12,716]

2 hours ago, mrc said:

do you mean you replaced the 4 inch engine drive pulley with a 5.25 inch hydro pulley? 

 

I did this on one of my tractors and replaced the transmission pulley with a 4 inch. I think that tractor now runs closer to 15mph in high 3rd. I typically use low range more often now. 

 

To be honest, it's about as fast as I would make one of these tractors go given the type of steering. I believe much faster would be very easy to flip over in a panic. 

 

The brakes on this particular tractor are excellent. But again, it's as fast as I'd prefer to go on a Wheel Horse. 

 

 

[Maxwell-8 4,357]

7 hours ago, mrc said:

do you mean you replaced the 4 inch engine drive pulley with a 5.25 inch hydro pulley? 

It currently has a one to one pulley ratio, but given the fact the diesel engine doesn't rev that high. It is slightly faster over stock. 

 

4 hours ago, kpinnc said:

I did this on one of my tractors and replaced the transmission pulley with a 4 inch

How is the input bearing holding up? What oil are you running?

 

4 hours ago, kpinnc said:

But again, it's as fast as I'd prefer to go on a Wheel Horse. 

Yes, I do believe that as well. I have a disc brake conversion set ready for this tractor. As This tractor when finished will be around 900 to maybe 1000lbs. 

[kpinnc 12,716]

1 hour ago, Maxwell-8 said:

How is the input bearing holding up? What oil are you running?

 

So far as I can tell there has been no damage. Standard 90 weight. 

[Wild Bill 633 854]

14 hours ago, Maxwell-8 said:

Most company's that sell this size bearing are saying a max rpm anywhere from 8.000 to 15.000rpm. 

What company? FYI, the bearing is a Koyo B-107, full complement needle bearing with a limiting speed of 4500 RPM.

[Maxwell-8 4,357]

1 hour ago, Wild Bill 633 said:

What company

I just searched the bearing size.

SKF is the most available here.

 

If I spin the input at shaft at 4000rpm, With the 27" tires. It would be 13.5mph or 22kmh

The diesel spins to about 2800rpm. So that would be a 6Inch pulley in the front, a 4" in the back. 

 

 

 

[ebinmaine 68,663]

1 hour ago, Wild Bill 633 said:

What company? FYI, the bearing is a Koyo B-107, full complement needle bearing with a limiting speed of 4500 RPM.

 

Do we know what the duty cycle percentage rating is at 4500 rpm?

 

If that is at 100% or even 80%, I would imagine that short spans of time at a slightly higher RPM shouldn't do too much damage.

Obviously, doing that at your own risk.

Your mileage May vary.

Keep Out Of Reach of children.

Don't try this at home, we are professionals.

 

 

What I'm getting at here is that many things are rated at a certain RPM and load bearing for a certain amount of time.

 

 

 

Obviously we want to keep in mind that the bearings are easy enough to replace but the shaft and the case, not so much.

 

 

 

[Maxwell-8 4,357]

13 minutes ago, ebinmaine said:

Obviously we want to keep in mind that the bearings are easy enough to replace but the shaft and the case, not so much.

Yes indeed. I have seen ratings of 8000 rpm, but the bearing in it stock, are the KOYO, like @Wild Bill 633 says, they are rated for 4500 rpm. Stock they run half that. I don't feel comfortable running 4000rpm. 

 

Even though, I have completely stock Jacobsen 3 wheeler that is running stock a 1:1 pulley ratio. On a very similar transmission. It came factory spinning the input that fast. May have to look into the differences between transmission. 

 

 

Cutting gears for the wheelhorse looks like a fun and learnfull challenge. The right way to speed up a horse.

Edited December 31, 2024 by Maxwell-8

[Wild Bill 633 854]

Fabricate quick-tach a tow bar.

Edited December 31, 2024 by Wild Bill 633