Increasing rear tire size on Toro 42 inch Timecutter

[BudLight72]

Also have a 4235 with the 18 x 7.50 - 8" tires and wheels.

I saw another machine with 20 x 10 - 8" setup; anyone know what width wheel is needed to run those tires?

FWIW, the first two internet whores who paid google to have their site at the top of the search are actually "out-of-stock" on the tires, but waste your time hoping you'll click on something else on their site.

jack vines

One thing you have to be aware of is the offset of the wheel. In other words, when you mount the new tire and wheel, will it rub the frame or fender? That’s the issue I encountered resulting in the requirement for 2” spacers to clear frame.

 

[packardv8]

Agree, if one is changing wheels, knowing the offset of both OEM and replacement wheels is critical.

If one is just replacing the OEM tires with a taller, wider tire, each tire is rated for use on wheels from XX to XY widths. With automobile tires, that specification is furnished by the manufacturers. With all the small machine tires coming from Asia and mostly China, the wheel width specs are thus far impossible to find.

jack vines

 

[BudLight72]

Agree, if one is changing wheels, knowing the offset of both OEM and replacement wheels is critical.

If one is just replacing the OEM tires with a taller, wider tire, each tire is rated for use on wheels from XX to XY widths. With automobile tires, that specification is furnished by the manufacturers. With all the small machine tires coming from Asia and mostly China, the wheel width specs are thus far impossible to find.

jack vines

Have you tried looking for a wheel/tire set that might be available at Tractor Supply or Walmart or even a mower dealer where you could measure the offset to see if or how it would work? I went to a toro dealer and measured the combo size that I wanted. Then located the set for that mower on the internet (shown above). Seems like most of the residential mowers have a 4x4 bolt pattern so you might find what you’re after on a different brand mower. You can get spacers on Amazon.
One more thing. If you’re going to a two inch taller tire, make sure that your deck will allow for you to adjust the deck pitch to compensate for the additional height.

 

[packardv8]

Have you tried looking for a wheel/tire set that might be available at Tractor Supply or Walmart or even a mower dealer where you could measure the offset to see if or how it would work? I went to a toro dealer and measured the combo size that I wanted. Then located the set for that mower on the internet (shown above). Seems like most of the residential mowers have a 4x4 bolt pattern so you might find what you’re after on a different brand mower. You can get spacers on Amazon.

That works if one wants to spend $250 to increase the tire size.

I have access to a pair of 20 x 10 - 8"s for free if they can be used on the OEM wheels.

jack vines

 

[BudLight72]

That works if one wants to spend $250 to increase the tire size.

I have access to a pair of 20 x 10 - 8"s for free if they can be used on the OEM wheels.

jack vines

Ok, now I understand. Good luck on getting this sorted out. Tough to beat free..

 

[7394]

Will be a new challenge to the EZT 2100 hydros.

 

[packardv8]

Seems like most of the residential mowers have a 4x4 bolt pattern so you might find what you’re after on a different brand mower. You can get spacers on Amazon.

Interestingly, I went to a mower scrap yard and every rider there mounted the wheels directly on the round axle and keyway. He didn't have any 4x4 wheels.

Looking more closely at the Toro 4235, it mounts the 4x4 flange on the round axle with a keyway. Doesn't take much leap of imagination to think of mounting a pair of the 20" axle mounted wheels directly. The one factor which must be confirmed is the stop which locates the wheel on the axle so the nut may be tightened to secure it.

However, since Toro spent the money to add the 4x4 flanges, there must be some necessity and maybe the direct axle mount isn't strong enough.

jack vines

 

[sgkent]

five pages.

the real question is why would the manufacturer and engineers go to the trouble of smaller tires on one unit when it would have been easier to make all the units, regardless of deck size, with the same tires. The economics of scale would want all the parts to be the same. Using different parts in production of the same unit takes up time, space, and costs more money stocking inventory at the factory. Smaller tires would require less power, is there a difference in engine size that accompanies deck sizes?

 

[packardv8]

the real question is why would the manufacturer and engineers go to the trouble of smaller tires on one unit when it would have been easier to make all the units, regardless of deck size, with the same tires. The economics of scale would want all the parts to be the same. Using different parts in production of the same unit takes up time, space, and costs more money stocking inventory at the factory. Smaller tires would require less power, is there a difference in engine size that accompanies deck sizes?

Yes, No, Maybe. All I know for certain is the manufacturers of less expensive, less powerful tractor style riding mowers usually come with the 20"x10" where Toro chose the 18"x7.50" tires for the 4235 ZTRs.

Smaller tires don't require less power, but a smaller diameter tire produces more pulling power at a slower ground speed. Since ZTRs are seldom asked for a max power dead pull, it's pretty much moot.

A potential downside of a wider tire footprint might be tearing more turf if one often turns with the inside wheel stationary.

FWIW, I just found a source where I can buy a new 20"x10" tire on a new 4x4 wheel for $45 plus shipping.

jack vines

 

[7394]

following..