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What size post driver do I need

Updated: 21 October 2026

You have the post in one hand and a listing that says any fence post. What size post driver you need is an opening wider than the post’s widest point, wings and corners included. If that point is larger than the printed bore, the driver will not start. In this set the manual bores are 2.7, 2.9 and 3.2 inches. The cards are on the [pile driver comparison](/hub/flooring-tools-and-accessories/pile-driver). The other criteria are on the [fence post driver buying guide](/hub/flooring-tools-and-accessories/pile-driver/sub/pile-driver-buying-guide). Peter F. used the listings captured on 19 October 2026 and did not measure your timber. A qualifying purchase can earn us a commission at no extra cost to you.

You have the post in one hand and a listing that says any fence post. What size post driver you need is an opening wider than the post’s widest point, wings and corners included.

Our top picks

Yarlung Yarlung 17 lb post pounder

Best overall

Yarlung Yarlung 17 lb post pounder
9.4/10about £36.99
View offer
iHYTOON iHYTOON green post pounder

Alternative

iHYTOON iHYTOON green post pounder
9.0/10about £41.85
View offer
Sptchapn Sptchapn post rammer

Alternative

Sptchapn Sptchapn post rammer
8.2/10about £39.92
View offer
On this page
  1. 1.Measure the widest point
  2. 2.What 2.7, 2.9 and 3.2 inches can take
  3. 3.Why a 4x4 does not enter a round 3 inch tube
  4. 4.Petrol sockets are the same problem

Measure the widest point

Measure the post where it is fattest. On a T-stake that is the flange. On a square it is the diagonal, because a round tube has to swallow the corner, not the face. Slide the post into the tube by hand before you lift. If it binds at the mouth, driving will jam it. Conservation Handbooks notes that an oversized tube hides the post so the line wanders. A 5–10 mm clearance rule from other makers is theirs, not a measurement of these six Amazon tubes.

What 2.7, 2.9 and 3.2 inches can take

Yarlung B0FKMVX5D3 states 2.7 inches inside, also written 6.8 cm. A bullet also says any types of fence posts. The 6.8 cm line is the one that limits that bullet. PYYB states the same 2.7 inch interior. A UK reviewer said a 4x4 will not enter, and used the bore on tree stakes and electric-fence stakes. iHYTOON states 2.9 inches inside. One UK reviewer says a 3 inch post will not fit. Sptchapn states 3.2 inches, the widest round bore here, and the rammer is still 2.76 kg. A wider claim does not make it heavy. Try the post in the tube.
Yarlung Yarlung 17 lb post pounder

Testsieger

Yarlung Yarlung 17 lb post pounder
9.4/10about £36.99
View offer

Why a 4x4 does not enter a round 3 inch tube

A 4x4 in UK timber talk is often about 100 mm on the face. The corner-to-corner distance is about 141 mm. The tube has to pass the corner. The widest round bore stated here is 3.2 inches, and a UK reviewer has already refused a 4x4 in a 2.7 inch tube. Square posts that do drive use a square holder. Petrol Post Driver sells a 107 × 107 mm adaptor for its own drivers, and Portek sells a holder for 4x4. Neither is in these six boxes. If your post is a 4x4, skip every narrow round tube here.

Petrol sockets are the same problem

A socket is the petrol version of a bore. Generic B0HJ6WFQ57 states 2.17 inch and 2.76 inch sockets. That is the same narrow band as the 2.7 inch tubes, not a 4x4 opening. Gdetnysty B0H1G51HG3 includes two sockets and does not state their diameters. Do not borrow 52 mm, 78 mm or 107 mm from a hire page and paste them onto this ASIN. Until a diameter is printed, the about £429.99 driver has an unknown opening. The class fork is manual or petrol post driver.

Common questions

What do I measure on the post?
Measure the widest solid point: the flange of a T-stake, the ears of a U-channel, the diameter of a round post including swell, or the corner-to-corner diagonal of a square. A face measurement on a 4x4 understates what a round tube has to swallow. If the post will not enter by hand, it will not drive. Clearance should be small. A very loose tube hides the top and the line wanders.
Will 2.7 inches take T-posts?
It is the size these listings aim at T-posts, U-channels and thin stakes. Yarlung states 2.7 inches / 6.8 cm and names T-posts and U-posts. PYYB states 2.7 inches, and a UK reviewer used that bore on tree stakes and electric-fence stakes. A T-stake with a wide flange can still be too fat. Measure the flange. The word T-post on the title is not a gauge.
Will a 2.7 inch driver fit a 4x4?
No. A UK reviewer with the PYYB 2.7 inch, 3.5 kg tube said a 4x4 will not enter, and that the bore suits smaller stakes. A 100 mm square is about 141 mm on the diagonal, which a round 2.7 inch tube cannot pass. The same refusal applies to any other 2.7 inch tube in this set, including the heavier Yarlung listing. A square holder is a different part, and it is not included here.
Is 3.2 inches enough for a 3 inch round post?
Sptchapn states 3.2 inches, and that is the widest round bore printed in this set. The listing does not show a reviewer checking a 3 inch post in that tube, and swell, a collar or an out-of-round section can still bind. Say the page claims 3.2 inches, then try the post. Do not treat the half-inch gap as guaranteed clearance. The rammer remains a light tube if it does fit.
Why did one review say 2.9 inches failed a 3 inch post?
Because the post was larger than the hole. The iHYTOON bullets state 2.9 inches inside. A UK reviewer said their 3 inch post would not fit, and that a 3.2 inch reading of the description did not match the tube. A US note estimates about 2.75 inches. Use 2.9 inches as the printed bore. A 3 inch post needs a larger stated opening, and even then you try it.
What posts do the petrol sockets fit?
On the about £156.72 Generic listing, only what fits the stated 2.17 inch or 2.76 inch sockets, and the bullets say soft ground. That is not a 4x4. On the about £429.99 Gdetnysty listing the two sockets have no printed diameter, so you cannot name a post size. Hire-sleeve sizes from other machines are not these sockets. An unknown socket is a reason to leave the listing.

Related pages

Best fence post driver

Pile driver

Fence post driver buying guide: bore, then the weight

How to use a fence post driver with a short, safe drop

Manual or petrol post driver for a short fitting run

Sources

Public UK sources and amazon.co.uk listings, checked on 19 October 2026. Shelf prices, bores and weights are the figures in the display file.

  1. Planning Portal fences, gates and garden walls (retrieved 19 October 2026)
  2. GPDO 2015 Schedule 2 Part 2 Class A (retrieved 19 October 2026)
  3. HSE hand-arm vibration regulations (retrieved 19 October 2026)
  4. HSE noise at work regulations (retrieved 19 October 2026)
  5. HSE HSG47 avoiding danger from underground services (retrieved 19 October 2026)
  6. LSBUD line search before you dig (retrieved 19 October 2026)
  7. Conservation Handbooks post driver (retrieved 19 October 2026)
  8. Husqvarna UK two-stroke mix for a hedge trimmer (retrieved 19 October 2026)