Register free!
Search
 
     

The Green Industry's Resource Center


Click for Weather
Reply
 
Thread Tools Display Modes
  #1  
Old 10-28-2001, 11:00 PM
Wayne Offiler Wayne Offiler is offline
LawnSite Member
 
Join Date: Jul 2000
Location: N. Kingstown, RI
Posts: 113
Getting more ground speed from walk-behind

A couple of weeks ago, I mentioned that my Bunton 52' hydro wb topped out at about 5 mph, even after putting on larger drive tires. (I use a Proslide). Someone suggested that I put smaller pulleys on the hydro pumps (I think it was Mr. Stone).
I could also put a larger pulley on the engine end. Either would spin the pumps faster, pushing out more fluid.
Has anyone done this? Did it give you more speed?
My main concern is that I might be putting more stress on the pumps than they were designed for.
Reply With Quote
  #2  
Old 10-29-2001, 01:47 AM
lawnMaster5000 lawnMaster5000 is offline
LawnSite Senior Member
 
Join Date: Jul 2000
Location: St. Louis Missouri
Posts: 589
thought about it but then decided exactly what you are concrearned about. so i never did, but i am sure that they can be spun a little faster. but also, make sure that theya re adjusted to use full capabilities, some mowers dont use the hydro pumps/motors to their full potential.
__________________

Happy Mowing from StL
-Scott Marquart

www.westcountylandscaping.com
Reply With Quote
  #3  
Old 10-29-2001, 07:42 AM
MOW ED's Avatar
MOW ED MOW ED is offline
LawnSite Fanatic
 
Join Date: Jan 2000
Location: N.E. Wisconsin
Posts: 5,029
Ask Engineer Mower Guy (aka Berry from Gravely). I demo'ed a prototype Gravely Hydro this summer that I'd swear did at least 10MPH wide open. I think they tamed it down a little on the production model.
When your in the market, make sure you try one of these out , lots of great ideas incorporated in the new Gravely WB's.
Good Luck
__________________
Check out the SPONSORS, they keep this site going!!!
Reply With Quote
  #4  
Old 10-29-2001, 08:07 AM
Eng Mwr Guy Eng Mwr Guy is offline
Gravely Manufacturer
 
Join Date: Jan 2001
Location: Appleton, WI
Posts: 249
Either increasing the size of the engine pulley or decreasing the sheave size of the input to the hydro pump would speed it up.

Usually, the max input into the pump is 3600rpm but not always. You would need to get the specifications of the pump to find out what the maximum input speed should be. You can then play with pulleys and such. If you do not increase the pump speed past the design limit you shouldn't have any problem with more than normal pump failures.

LM5000 is correct. It may be you are not getting full sweep of the hydro pump arm into the pump. If a linkage is hosed up or some kind of interference this could be the culprit also.

Another, less often used way is to decrease the size of the wheel motors. This would decrease "power" while increasing speed. This would potentially cause hoses and such to be reexamized for pressure and the entire system should be looked at.

The new Gravely Hydro, in the high linkage position does only 8.5mph. "Normal" from the factory speed will be 6.3mph.

I did let Ed use the fire breathing dragon WB prototype #2 that was just a hair under 10mph. He even lived to tell about it.

Barry
Gravely Guy
Reply With Quote
  #5  
Old 10-29-2001, 08:37 AM
scott's turf scott's turf is offline
LawnSite Senior Member
 
Join Date: Oct 2001
Location: NH
Posts: 949
As a mechanical engineer and a landscaping company owner you could have a couple of problems trying to increase the spead of your mower. First of all the engines are designed for a specific torque setting. This is simply force X distance. The larger the pully, the less force required to due the same job. A simply example of this is trying to move your truck from a dead stop in 5 gear instead of 1st. The engine will stall. This may happen as well if you are going up a hill with your mower or you have a heavy rider hanging off the back. This continuing stress on the mower and drive components could lead to premature breakage. Companies would make their mower faster in a heartbeat if it only required changing the size of a pully. I am sure warrenties would be voided as well if a problem resulted from your modification.
Reply With Quote
  #6  
Old 10-29-2001, 08:41 AM
Eng Mwr Guy Eng Mwr Guy is offline
Gravely Manufacturer
 
Join Date: Jan 2001
Location: Appleton, WI
Posts: 249
**I am sure warrenties would be voided as well if a problem resulted from your modification.**

Of course. I assumed this unit was out of warranty.

Modify at your own risk. Dealerships might not support you if the modification goes poorly and they have to fix your attempted mod.

Barry
Gravely Guy
Reply With Quote
  #7  
Old 10-29-2001, 10:04 AM
TLS's Avatar
TLS TLS is offline
LawnSite Fanatic
 
Join Date: Jan 2000
Location: N&W Philadelphia Suburbs
Posts: 7,938
How fast can you comfortably walk? This is why manufacturers make them only go 5-6mph. They dont count on sulky use. Plus most of these walkbehinds are too underpowered in the engine department to keep up with ZTR speeds while still cutting grass. If you did the larger tire size modification and your still not happy, then these other mods aren't going to make you much happier. My only other suggestion would be to increase engine RPM's. Make sure that they are AT LEAST 3650 NO LOAD. You can go higher, but I see entirely too many new mowers delivered spinning only 3450 RPM's.
__________________
TLS
2004 GMC 2500HD Reg Cab BOSS 9.2 V-Plow
2013 eXmark LazerZ X-Series 60" 34hp EFI (RED) Kohler
2006 Hustler SuperZ 28EFI 60" Power Chute Design OCDC SOLD!
Perma-green Magnum
1996 48" SCAG Belt WB 14hp Kawasaki Classic Deck
Echo 2 strokes PB-755 & SRM 280
Eastman WM20H 20" Commercial Push mower (NEW for 2013)
Commercial Lawnboy trim mower 3-FOR SALE!http://www.lawnsite.com/showthread.php?t=424203
Solo since 1980
Reply With Quote
  #8  
Old 10-29-2001, 10:17 PM
little green guy little green guy is offline
Registered User
 
Join Date: Feb 2000
Location: Somerset County, New Jersey,
Posts: 955
Put on smaller diameter hydralic lines, I did this on a scag and it made it alot quicker.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump





Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©1998 - 2012, LawnSite.comô - Moose River Media
All times are GMT -4. The time now is 05:25 PM.

Page generated in 0.09082 seconds with 7 queries