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Toro 20334

Wheels and drive gears for the Toro 20334

Short answer

The rear wheel, 59503, is the same across every range we checked. The front is not: Toro lists drive gear 59502 for the 315- and 316-series ranges, and 8 in. front wheel 137-4833P for the 400-series range instead.

Verified options

What we have verified

Wheels and drive gears recorded for the Toro 20334
PartSerial rangeStatus
595038 inch Replacement Rear-Wheel-Drive Wheel for Lawn MowersAllConfirmed fit
59502Replacement Front Wheel Drive Internal Gear315000001–315999999Confirmed fit
59502Replacement Front Wheel Drive Internal Gear316000001–316999999Confirmed fit
137-4833P8 Inch Front Wheel400000000–401999999Confirmed fit
59502Replacement Front Wheel Drive Internal Gear400000000–401999999Not verified
137-4833P8 Inch Front Wheel315000001–315999999Not verified
137-4833P8 Inch Front Wheel316000001–316999999Not verified

What decides it

The numbers that matter here

Front, 315- and 316-series

Drive gear 59502

Toro’s name calls it an internal gear and its description calls it an 8-in. wheel assembly. We quote both rather than deciding which one arrives in the box.

Front, 400-series

8 in. front wheel 137-4833P

The listing changes here — one range later than the maintenance kit changed. The two boundaries are independent.

Rear, all three ranges

8 in. rear-wheel-drive wheel 59503

The same number in every range we opened. Toro describes it for rear-wheel-drive machines, and does not list it for the front-wheel-drive 20339.

What we are not telling you

Whether any of these substitute for each other

Toro’s pages show which part appears under which serial range. They do not state that a part will not fit elsewhere, so neither do we. If you need to substitute, ask a dealer.

In detail

Choosing wheels and drive gears for this mower

This is the page that shows why "check your serial number" cannot be reduced to a single date. The 20334 has two boundaries, and they are not in the same place.

The engine maintenance kit changes between the 315- and 316-series ranges. The front of the machine changes one range later. Toro lists Replacement Front Wheel Drive Internal Gear 59502 for both 315000001–315999999 and 316000001–316999999, then does not list it for 400000000–401999999, where 8 Inch Front Wheel 137-4833P appears instead. So a 316-series machine sits under the newer kit and the older front part. If you work out "mine is a late machine" from the kit and then order the front wheel on that basis, you are ordering from a listing that does not cover your serial number.

One thing that absence does not mean: Toro still lists 59502 for the 20339 in that model’s own 400-series range. Whatever changed, it is specific to this machine’s listing rather than the part disappearing from Toro’s catalogue.

At the back, 59503 — which Toro describes as an 8 inch rear-wheel-drive replacement wheel — appears in all three ranges we opened. The front-wheel-drive 20339 does not list it in either range we opened for that machine. We are not going to tell you why, because Toro does not say; we can only tell you what each listing shows.

We have not opened the eleven other ranges Toro publishes for this model number, so we cannot tell you whether the front changes again after 401999999.

The mistake we see most

Deciding "mine is a later machine" from one part and then ordering every other part on that basis. On this mower the kit and the front wheel change at different points.

Method

How we established this

We compared Toro’s parts listings for model 20334 under three serial ranges and recorded which wheel and drive-gear numbers appear in each. We cross-checked 59502 against Toro’s listing for the 20339 to confirm the part is still published, so that its absence from the 20334’s later range is described accurately as a change to that machine.

All parts for the Toro 20334

Provenance

Sources

Last verified against these sources on August 17, 2026.

  1. 1

    Parts — 22" Personal Pace Electric Start Mower, model 20334, serial range 315000001–315999999

    The Toro Company · Primary source · Accessed August 17, 2026

    Toro’s official parts listing for the earliest of the three ranges we verified. Lists 20234 (Engine Maintenance Kit for Briggs & Stratton Engine) and 108-8120 (TRACTION ASSIST KIT [PPG2]). Also lists 38991, 59534P, 59502, 59503 and 490-7462. The range selector on this page names thirteen further serial ranges for the same model number.

  2. 2

    Parts — 22" Personal Pace Electric Start Mower, model 20334, serial range 316000001–316999999

    The Toro Company · Primary source · Accessed August 17, 2026

    The next published range. Lists 130-8148 (Briggs & Stratton EXi Engine Maintenance Kit Replacement) and 131-4590 (Traction Assist Handle) where the previous range listed 20234 and 108-8120. Still lists 59502; 137-4833P does not appear.

  3. 3

    Parts — 22" Personal Pace Electric Start Mower, model 20334, serial range 400000000–401999999

    The Toro Company · Primary source · Accessed August 17, 2026

    The later range. Still lists 130-8148 and 131-4590, so the maintenance kit does not change again here. It lists 137-4833P (8 Inch Front Wheel) and does not list 59502 — a second, separate boundary within the same model number.

  4. 4

    Parts — 22" SMARTSTOW Variable Speed High Wheel Lawn Mower, model 20339, serial range 400000000–401999999

    The Toro Company · Primary source · Accessed August 17, 2026

    Lists 130-8148 in place of 20234, and adds 137-4837P (Replacement 11 in. Rear High Wheel). Still lists 38990 and 59502.