By Jerry Muncie (Jmuncie) on Sunday, October 18, 2009 - 09:40 pm:

Oh yeah, this started with snow. Snow is similar to dirt in that you're limited by the shear strength of the snow. You can also greatly improve the shear strength of snow by packing it. If I had to plow snow (and I don't) I'd go wide to get the surface area and add a bunch of weight. Back when we got enough snow to mess with in central Indiana, we ran 23-10.50 turf tires with chains and 40 lb wheel weights (per wheel) with pretty good luck. That combination worked much better than the 23-8.50 Carlisle ags with old style CC weights on my 126 used to pull my daughter on a sled. They tended to float on top of the snow until the going got tough. Then they'd dig a hole that they couldn't climb out of.

By Richard Palmer (Rpalmer) on Sunday, October 18, 2009 - 08:52 pm:

So for me.. "Joe ol man" pushing snow with my Cubs, do I want a narrower or wider foot print? I just want to maximize my tractors power.

By Jerry Muncie (Jmuncie) on Sunday, October 18, 2009 - 08:21 pm:

Drag racers and pullers do need a bigger contact patch, but for different reasons.

For starters, frictional force between two surfaces is equal to the coefficient of friction multiplied by the normal force (force pushing the two surfaces together). Most of the time, the coefficient of friction is a constant for the pair of surfaces, so the frictional force is independent of contact area and increases proportionally to the normal force. Double the normal force and the frictional force doubles.

Rubber on asphalt is an odd case. As contact pressure goes up, the coefficient of friction decreases. Double the normal force and the frictional force doesn't quite double. Therefore, you can increase traction of tires on asphalt by increasing the contact area.

For pullers, it's an issue of shear strength of the soil they're pulling on. There's a limit to how much force the tire can exert on a square inch of the track before the upper layer of soil shears away from the track. In order to increase the pulling force, increase the square inches of soil being sheared away from the track.

By randy littrell (Rlittrell) on Sunday, October 18, 2009 - 02:32 pm:

Same reason drag cars use the biggest tire, bigger contact patch.

I think the NQS guys play with taller,shorter,wide rims and narrow rims, but I think that is more to do with keeping the motor in the power band for the available traction.

Randy

By Richard Palmer (Rpalmer) on Sunday, October 18, 2009 - 01:25 pm:

Hey Guys. I have a question. I understand that all things being equal a narrow tire puts more psi to the ground. So why do pullers use the widest tires they can fit on their machine? Is it because of the sled's transfer of weight? Thanks.

By Ryan D Wilke (Rwilke) on Monday, October 12, 2009 - 06:55 pm:

Jerry M.,
VERY INTERESTING!
Thanks for the education!

Ryan Wilke

By Jerry Muncie (Jmuncie) on Monday, October 12, 2009 - 02:20 pm:

Bruce,

On crank-fired ignition systems it's much easier to fire at the top of every stroke than to differentiate between compression and exhaust stroke. On a horizontally opposed twin, firing at the top of every stroke eliminates the need for a distributor.

By Ryan D Wilke (Rwilke) on Monday, October 12, 2009 - 09:58 am:

Bruce N.,
Do you have any idea as to why the manufacturer would set up the newer engines (i.e., Magnums and Commands) to fire the sparkplug on non-compression strokes - Maybe for emissions sake???

Ryan Wilke

By Bruce Nolte (Bnolte) on Saturday, October 10, 2009 - 01:27 pm:

The K series engines have their ignition lobe running off the camshaft, and are ground so that they only fire every other revolution.

By Todd Markle (Farmallgray) (Tmarkle) on Saturday, October 10, 2009 - 12:24 pm:

Never mind. I was looking at an old profile from an old post. I found his new profile.

By Todd Markle (Farmallgray) (Tmarkle) on Saturday, October 10, 2009 - 11:35 am:

Has anyone heard from, or know how to get in touch with James Diederichs? His profile no longer exists. He used to post a lot on this topic.

By Jerry Muncie (Jmuncie) on Saturday, October 10, 2009 - 10:58 am:

I was working on a K321, so it was firing only on compression.

By Todd Markle (Farmallgray) (Tmarkle) on Saturday, October 10, 2009 - 09:25 am:

Jerry M,
The ones with points are that way. the Magnums and commands fire on every revolution.

By Jerry Muncie (Jmuncie) on Saturday, October 10, 2009 - 07:07 am:

I have a Fluke automotive multimeter--model 80 I think but not sure and I'm not home to check. I bought it because it had the tach capability and the thermocouple probe. The inductive pickup was a separate purchase for about $75. I've never been able to get a reliable reading on a one lung Kohler with it either. I don't remember the exact range of readings because it's been several months since I tried, but it seemed to jump (rapidly) from too low to about double what I expected to see. The low readings could be weak spark, but I don't understand the highs. Kohlers do only fire at the top of compression stroke and not at the top of the exhaust stroke, right?

By Bruce Nolte (Bnolte) on Friday, October 09, 2009 - 08:14 pm:

I've been trying to use a Fluke Frequency Counter (1970s vintage) to try and measure engine speed as a function of the frequency i.e 30hz = 3600 RPM if you get a pulse every other revolution of the crank. I guess due to all of the weird harmonics and spikes, I haven't been able to make it work yet, using the points side of the coil to ground as my reference. Might try hauling my old Tektronix O-scope out and give it a whirl.

Too cheap to buy a tach if I can make an existing piece of test equipment work, plus my nerd side likes the challenge.

By George Klapp (Gklapp) on Thursday, September 17, 2009 - 02:39 pm:

check out this electric powered Cub conversion;

http://www.diyelectriccar.com/forums/showthread.php/electric-riding-lawn-mower-13510p4.html

By D. Ryan Mull (Dmull) on Tuesday, September 15, 2009 - 08:27 pm:

+1 top reduction pinion is another possibility

By Darren Sterley (Dsterley) on Tuesday, September 15, 2009 - 10:09 am:

Rick thanks
it was the same tack and the same guy read it
so the odd are saying most likley a reduction gear change
so it looks like the best way will be to pull the rear ends out and check the reduction gears i just wanted to make sure i wasnt missing something before i pull the rearends out thanks for the input

By Rick beem (Rbeem) on Tuesday, September 15, 2009 - 09:44 am:

Darren,
Two different tachs or the same? I'm guessing at the variation is from kohler vs briggs ignition, but I'm no Pro.
The best non-partial method I've found would be a "photo" tach that does use the ignition as a source.
I use a snap-on(blue point) unit, it uses reflective tape and a laser....dead on.



Otherwise it surely is possible that a different reduction gear may have found its way in there at some point....lots of puller parts floating around out there.

By Darren Sterley (Dsterley) on Tuesday, September 15, 2009 - 09:05 am:

thank you Dennis
sorry about that i did leave that out both tractors are the same both with 23-10.5-12 and all gears are about the same the 124 will walk away from the 70 in all 3 gears and the motors were checke with a tack and set to 4000 rpm
both tractors are set up the same theyre twins in everthin but looks and speed
thats why i was thinking maybe a reduction gear or possible ring and pionon gear

By Dennis Frisk (Dfrisk) on Tuesday, September 15, 2009 - 08:37 am:

DARREN - A quick check of the parts look-up will show the 124 has what is referred to as a 19 tooth second gear and the 70 has a 16 tooth second gear. First and third were always the same ratio therefore the same speed. You didn't mention it in your post but ONLY second gear is where Your 124 should be faster. Tire size, etc will also vary speed, larger dia. tires equals greater speed. There's also a stock 17-tooth second gear set that was available, think it was in the gear drive red tractors and maybe the quiet-lines. It's just a bit fater than the 16T but not as fast as the 19T. Relative speeds are 3.2 mph for 16T; 3.9 mph for 19T, and I think 3.4 mph for 17T, all with stock 23 inch dia. tires and 3600 rpm.

I have a 70 and a 72, well, actually the 72 would be a 144, and second gear in the 72 is actually too fast to mow but a really good gear for things like idling around with a cart, pulling a moldboard plow, lawn areator, but I have to mow in first gear. The 70 however will become my preferred mowing tractor when it gets a rebuilt K241 in it, that slower second gear is a GREAT mowing gear.

By Darren Sterley (Dsterley) on Tuesday, September 15, 2009 - 07:15 am:

Good morning all.
I have a guest ion about gearing I have a 124 with a K301 stock running 4000 rpms and as far as I know a stock rear-end and trany
my dad has a 70 with a stock 16hp Briggs twin running 4000 rpms with as far as we know trany but I walk away from him in all gears when driving around the 124 is faster then the 70 quit a bit.
I was under the impression that they should be the same gearing what would you guys check I was thinking the reduction gear in front of the transmission ore am I missing something any help would be appreciated thanks

By Dave Ross (Dross) on Wednesday, September 02, 2009 - 12:38 am:

Ryan, I got all my ideas for floating over ground from a local sod farm. they had a 4000 ford with 20.8 rear rubber and huge front tires I never got close enough to get the size off of. It looked strange but he could drive across a sod field and leave no impression pulling 8 or 10 gangs of real mowers.