Whats with Sears H.P. ratings ??

Im thumbin' through the sears flyer and I notice that instead of giving the h.p. ratings of a lawnmower they say "tourque rating" like instead of sayin' 5 h.p. they say 5 tourque rating. - And whats with the "fresh start" system......

Lawnmowers are more torque-dependent than horsepower, since there isn't much revving involved. Its a constant-speed torque output, even though that still generates a power.

Though I don't know why they don't just follow the market.

For a lot of years everyone used the h.p. reading and got used to it, thats how we learned that 3 h.p. is barely enough power to mow your lawn. I wonder if the small engine companys changed their ratings or if sears is just doing that for "effect"- the engine looks like a 6 horse, they just call it a 6 torque.

They do it because engine manufacturers are getting more torque out of the engines, but they have a low HP rating. Some years ago I bought a junker push mower that had a 2.5 HP tecumseh, but it mowed a LOT better than the exact same mower that had a 4.5. It's just torque. That 4.5 had a 2.375" bore and the 2.5 had a smaller bore & longer stroke and overhead valves which explains the higher torque rating.

If people knew that it had a 2 HP engine, and that a comparable brand had a 5 HP engine for the same price, which one do you think they will buy? I believe it's something that only Sears is doing at the moment. I'm not aware of anyone else using that marketing strategy.


I believe fresh start is a chokeless, primer bulbless starting system...and they are a major pain to start if the weather's cold. EPA has their hands in there....they're trying to limit emissions any which way they can. As we speak, I'm working on a mower that has a 29 HP EFI V-twin and a catalytic converter built into the muffler.

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"it is better to appear ignorant than to open your mouth and remove all doubt"--Mark Twain

<font size=-1>[ This Message was edited by: mavman on 4/20/07 7:53am ]</font>

I was at costco a few weeks ago when a mower caught my eye. It looked like a nice unit with a honda engine and stainless body, (deck?). I couldn't find a hp or torque rating anywhere on it or the box or anywhere. Only thing different between the two sitting there was the size of the blade which was clearly labeled on the side.

They figure that we dont need that information or that the info on the box could kill the sale cause people would shop around.... maybe.

A mower that produces 5ft/lb of torque at 5000rpm is going to cut grass a lot better than one with 5ft/lb at 2000rpm. HP was the equalizer, it combines torque and horsepower, seems like that would be much better fitting for a mower than a torque rating. Remember torque is simply force, but HP is work over time. That's why even big diesels are rated at HP, not torque, because HP is what gets the job done. So to answer your question, I have no friggin clue why they would change to a torque rating.
[addsig]

But Motorhead...

ANY lawnmower that spins 5,000 RPM is going to cut better than one spinning only 2,000 RPM.....

It takes HP to cut through a six foot swath that's 8 inches high, but it takes torque to keep the engine running for the first foot of cutting until the HP find's it's sweetspot in the rpm range that the torque will allow the blade to spin while cutting through 8 inches of grass...

Did that make sense? (it's all relative to the torque the engine can produce while the blade penetrates the grass and the engine slows in RPM's until the HP takes over and the engine run's strongest... that's your sweet spot...) [img]/forums/images/smiles/icon_smile.gif[/img]
[addsig]

BUT, with more RPM, it won't have to cut as much per swath... if you are pushing at 2mph, that's 176 feet per minute, and if the blade is rotating at 5000rpm that means each rotation it will only have to cut about 1/2 inch per rotation, which is just the tip of the blade hitting any grass. The 2000rpm mower will have to cut 2.5 times as much per rotation, so it will need roughly 2.5 times more torque just to cut the same grass without slowing down. So see why horsepower is more important now? If the 2000rpm engine does indeed produce 2.5 times more torque than the 5000rpm engine, they will both break even (and will also both be making the same HP, btw).
[addsig]

If it were based only on blade rpm per cutting speed, you could just put a 4-tine blade on it, then each blade will cut less.