Replacement Tires for Honda RT5000, H5013, and H5518 Tractors

It is *very* difficult to find replacement tires in the original sizes for these Honda tractors. Lots of people have asked about tire conversions. I've considered all sorts of trailer, golf cart, ATV, and small tractor and utility tires and wheels looking for cheapish and readily available replacements. This page represents what I think I know as of May 2007. Please send any additions/corrections to honda@textwire.org.

NOTE! I am not a tractor designer, tractor dealer, tire engineer, or particularly knowledgeable person.
If you use any of the information here and if Things Go Really Bad, don't bother to call.
Take care; be careful; think for yourself. I AM NOT RESPONSIBLE.

The original Honda turf tires and wheels on my H5013 are:

Front wheel:   "12x5"
meaning the wheel is 12" in diameter and 5" in width. The wheel has a "4/4.75" bolt pattern, meaning that there are four stud holes on a 4.75" diameter circle (in metric, this is a "4/120.7" bolt pattern). This is a very unusual bolt pattern! The wheel has a center hole 3.125" in diameter to fit the round boss on the wheel hub. The wheel center is slightly offset toward the *outside* of the wheel (the center disk is ~2.5" from the edge of the outside wheel rim and ~3.25" from the edge of the inside wheel rim).
Front tire:   Ohtsu "GreenGrip" turf tire: "20x7.00-12"
meaning that the tire is approximately 20" in diameter and approximately 7" wide.

Rear wheel:   "14x6"
meaning the wheel is 14" in diameter and 6" in width. The rear wheel (of course) has the same 4/4.75 bolt pattern and 3.125" cutout as the front wheel. The rear wheel center disk is slightly offset toward the *inside* of the wheel (the center disk is ~4" from the edge of the outside wheel rim and ~3" from the edge of the inside wheel rim).
Rear tire:   Ohtsu "GreenGrip" turf tire: "24x8.00-14"
meaning that the tire is approximately 24" in diameter and approximately 8" wide.

The trouble with the original Ohtsu turfs is that they are both unusual sizes: they are taller and narrower than most all the tires fitted to other makes of garden tractors, to golf carts, and to ATVs.

Notes about Tire Size and Four Wheel Drive
Almost every RT5000, H5013, and H5518 tractor I've seen has been 4 wheel drive. If you have a 2 wheel drive tractor, you can skip this discussion!

Ideally, when in 4 wheel drive the front and rear tires of a 4 wheel drive vehicle would travel the same distance over the ground. If they don't, either the fronts will be "pushed" or the rears "pulled," depending upon which end of the vehicle has better traction. This is not good for tire life since some tires are being scrubbed instead of pulling equally. It's not good for the transmission and gear train of the vehicle either.
In fact, in the real world the distances traveled by the four wheels of a vehicle change constantly. As the vehicle turns (or even as one wheel goes over a bump or runs through a depression), all four wheels will cover different distances over the ground: the outside wheels in a turn obviously travel further than the inside wheels.
To avoid as many problems as possible, designers of 4 wheel drive vehicles choose front/rear gear ratios and front/rear tire sizes to minimize tire scrub and transmission stress. For economy and simplicity, designers of 4 wheel drive passenger vehicles almost always choose four tires of equal size. Even so, 4 wheel drive vehicles can have built in problems. Some older, standard transmission 4 wheel drive passenger vehicles with manual transfer cases should not be driven very far in 4 wheel drive on hard surface roads. The simple, mechanical 4 wheel drive system can't compensate for the good traction of a paved road. As all four tires travel different distances relative to each other, some are "pushed" or "pulled" by the others, causing premature tire wear and added stress on the gear train. The situation is even more complicated for 4 wheel drive vehicles which use different size tires front and rear--like Honda tractors.

Tire Size and Four Wheel Drive Honda Tractors
Here I'm presuming that Honda designers chose original equipment tire sizes to minimize problems of tire wear and transmission stress.
The circumference of the original front Ohtsu 20-12 tires is ~62.5" (I measured tires that were properly inflated and looked to be about 95% of new). The circumference of the original rear Ohtsu 24-14s is ~75.75". Given these circumferences, the front/rear ratio for the original equipment tires is ~1.2:1. That is, in "normal" straight ahead travel on a level surface with no tire slippage, the front tires should rotate about 1.2 times for every 1 rotation of the rear tires. In looking for replacement tires I'm using this 1.2:1 ratio as an important indicator of whether the replacement tire set will be suitable for use in 4 wheel drive. Remember that the derivation of this ratio is reverse engineering of the most primitive sort. Who knows what target the Honda designers were using? Consider that:

  • The Honda designers chose an *existing* tire set (they did not manufacture their own tires, but chose available tires that were close enough to the ratio they wanted).
  • Honda-supplied R-1 ag tires for these tractors have a different front/rear ratio from the Ohtsu turfs: the R-1 ratio is about 1.26:1.
  • Tractors run very slowly (compared with passenger vehicles) and are mainly used on soft(er) surfaces. The softer the surface the greater the potential tire slip, but the easier on tire wear and transmission stress.
So, while I do not think there is a single magic front/rear tire size ratio which must be observed, we'll be happiest with a ratio of close to 1.2:1.

A turf style replacement tire:
Firestone (Bridgestone) makes the FARM SERVICE DIA TT R-3. This is a "Small-diameter turf tire designed for small tractors... Provides maximum flotation and minimum turf damage on lawns, cemeteries, golf courses, and sandy soils."
Picture of tread pattern © Firestone/Bridgestone:
FARM SERVICE DIA TT R-3
These sizes will fit the Honda's original turf-tire wheels (table © Firestone/Bridgestone):
FARM SERVICE DIA TT R-3
The 6-12 is a perfect fit on the stock Honda front wheel.
The 7-14 is recommended for a 5" rim: the Honda rear wheel is 6" wide.
The front/rear size ratio of this tire pair is reasonable, at 1.15:1 (using the quoted rolling circumferences, the way I measured the Ohtsu turfs).

Click here to find a Firestone agricultural tire dealer.

A ribbed agricultural style replacement tire:
Firestone (Bridgestone) makes the ALL TRACTION FIELD AND ROAD TL G-1. This is a heavily ribbed bar tire.
Picture of tread pattern © Firestone/Bridgestone:
ALL TRACTION FIELD AND ROAD TL  G-1
Three combinations of these sizes will fit the Honda's original turf-tire wheels (table © Firestone/Bridgestone):
ALL TRACTION FIELD AND ROAD TL  G-1
Combination 1: 5-12 (front) - 7-14 (rear)    front/rear ratio = 1.29:1
  The 5-12 is recommended for a 4" rim: the stock Honda front wheel is 5" wide.
  The 7-14 is recommended for a 5" rim: the Honda rear wheel is 6" wide.

Combination 2: 5-12 (front) - 6-14 (rear)    front/rear ratio = 1.19:1 (nearly perfect)
  The 5-12 is recommended for a 4" rim: the stock Honda front wheel is 5" wide.
  The 6-14 is recommended for a 5" rim: the Honda rear wheel is 6" wide.

Combination 3: 6-12 (front) - 7-14 (rear)    front/rear ratio = 1.17:1 (good)
  The 6-12 is perfect for the stock Honda front wheel.
  The 7-14 is recommended for a 5" rim: the Honda rear wheel is 6" wide.

As of May 2007 Miller Tire Co. (a company I have had good luck with in the past) sells Firestone Traction Field & Road 5-12s for $68; 6-12s for $75, 6-14s for $92. They do not list 7-14 Firestones, but do sell 7-14 Titan "Hi Traction Lugs" for $98. Go to the "Lawn & Garden Lug Tires" section of their website.
Click here to find a Firestone agricultural tire dealer.

Automobile tire replacements:
The cheapest solution to new tires using Honda's turf wheels I have found is to replace the original turfs with all-season style automobile tires.

A front auto tire replacement:
The best automotive tire size I can find that will fit the stock 12x5 front wheel is a 165/70R12. According to this tire calculator, a 165/70R12 tire matches up with the original Ohtsu as follows:

Tire:   Ohtsu 20x7.00-12 165/70R12
Section width:   6.5" 6.49"
Tread width:   6.5" ??
Diameter:   20" 21.09"
Circumference:   62.5" 66.25"

So, the 165/70R12 tire is 1/2" narrower and 1.09" taller than the original Ohtsu.

Still, 165/70R12 is not a common car tire size! One of the few tires in this size with a tread pattern that could work for a lawn tractor is the Yokohama Y372 (picture of tread pattern):

Yokohama Y372

As of 11/2006 this tire is available from tirerack.com (I've purchased from tirerack.com in the past; otherwise I have no connection with them!).

A rear auto tire replacement:
As you will see from the tirerack link, there is also a Yokohama Y372 in the 185/65SR14 size (the "85S SL") that will fit the Honda's stock rear wheel:

Tire:   Ohtsu 24x8.00-14 185/65SR14
Section width:   8" 7.4"
Tread width:   7.5" 5.5"
Diameter:   24" 23.6"
Circumference:   75.75" 73.7"

Published tread width of the 185/65SR14 tire is 2" narrower that the original Ohtsu, but section width is closer.

Using these auto tires together yields a front/rear tire size ratio of 1.11:1 (remember, the target is 1.2:1).

Other tire replacement options:

A true turf tire available for the rear:
There is a true turf tire available that will fit the stock Honda rear wheel. This is the Titan "Multi Trac C/S" in the 25/8.50-14 size (available from Miller Tire Co. Picture of the Multi Trac tread pattern:

Titan Multi Trac

This is an almost perfect replacement for the original Ohtsu turf tire.

Unfortunately I have been unable to find a matching turf tire that will fit Honda's stock 12x5 front wheel. Such a tire needs to be a) 20" or slightly less in diameter, b) less than 9" in section/tread width, and c) in a size to fit a 12" wheel. This last requirement is the most difficult!!

ATV tire/wheel conversions?
People have done ATV tire and wheel conversions for Honda tractors. I've looked long and hard for an inexpensive ATV tire and wheel combination that could work. As of now I've given up the hunt. For these main reasons I do not think such a conversion is both practical and cost effective:

  1. ATV tires are not available in sizes to fit original equipment Honda wheels, and I have found no stock ATV wheel which matches Honda's bolt pattern and center hole. This means either a custom wheel (a rim with a custom center made to fit the Honda's hub), or a custom wheel adapter that will let you mount a stock ATV wheel on the hub. Either choice is an expensive option.

  2. There are complications even if you go the custom wheel or wheel adapter route. Many (if not most) ATV tires are significantly wider in profile that the Honda's original equipment tires. This is not such a problem in the front, but clearance in the rear is tight. The new wheel or wheel adapter would need a big offset to push the new, fatter rear tire out away from the suspension and hear hitch. A big extension would put added mechanical stress on the tractor's bearings and CV joints.

  3. If the Honda is 4 wheel drive, I think it is safest to try for a front/rear tire size ratio of close to 1.2:1 (as discussed to death above). It could be tricky to find a set of front/rear ATV tires that comes close to this ratio....
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