Frisco E-Bike
Mechanic repairing a bicycle

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Inner Tubes

26x4.0 Fat Tire Inner Tube, Schrader Valve (generic)

The 26x4 tube is the full-size fat-bike counterpart to the 20x4 folder tube, and it is what most 26-inch fat e-bikes run. Generic butyl tubes in 26 x 3.5–4.5 (or 4.0–4.9) are widely sold; the branded ones from Kenda, Sunlite and CST are not meaningfully different from house brands. Schrader is the common valve on these bikes. Because a 4-inch tube holds a lot of air at low pressure, pinch flats from running too soft are the usual cause of death, so check pressure weekly and carry a spare on long rides.

26x4 fat-tire e-bikesSpares for the trail bag or garageRiders replacing a pinch-flatted tube

Current price and availability are shown on Amazon.

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Key considerations

  • Confirm size range covers 4.0 and valve type matches your rim
  • Run recommended pressures to avoid pinch flats
  • Inspect rim strip when replacing
  • Thorn-resistant versions are heavier but worthwhile in goathead country

Pros

  • Cheap
  • Widely available
  • Fits the standard fat-bike size

Considerations

  • No puncture protection
  • Heavy and bulky to carry
  • Seller quality varies

Features & specifications

Size26x4.0
ValveSchrader

Specifications are manufacturer-published figures or our own notes; confirm on the current listing before purchase.

Compatibility notes

  • 26-inch fat rims with tires in the 3.5–4.9 inch range; Schrader valve drilling

Goes well with

Related accessories

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Replacement parts

Confirm fitment on your bike before ordering — see each part’s compatibility notes.

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Bike maintenance in a workshop
E-Bike Tires

CST BFT (Big Fat Tire) 26x4.0

CST's BFT (Big Fat Tire) is a widely fitted original-equipment tire on 26x4 fat e-bikes and one of the cheapest ways to replace a worn one. The tread is a medium-knob all-rounder: it handles hardpack, sand and snow acceptably and hums a bit on pavement, which is the normal deal with fat tires. Wire-bead versions are the common, inexpensive ones; folding versions exist at a higher price. If you spend most of your time on the road, a smoother fat tire will roll easier, but for mixed use the BFT is a sensible default.

Best for: Replacing stock tires on 26x4 fat-tire e-bikes · Mixed pavement and trail riding · Budget-minded riders

View details & where to buy

Sold on Amazon

Mechanic working on bike components
Inner TubesFeatured

20x4.0 Fat Tire Inner Tube, Schrader Valve (generic)

A 20x4 tube is the single most common flat-repair purchase for folding fat e-bikes, and generic listings from brands like Kenda, CST, Sunlite and a dozen house brands are all essentially the same butyl tube. Buy by size and valve: 20 x 4.0 (often printed as 20x3.5-4.0 or 20x4.0-4.5), Schrader valve unless your rim is drilled for Presta, and a valve length that clears your rim. Keep two spares; on these bikes the rear wheel is a chore to remove and you do not want to do it twice for a patch that does not hold.

Best for: Folding fat e-bikes on 20x4 tires · Anyone who wants a couple of spares in the garage · Replacing a tube damaged by a pinch flat

View details & where to buy

Sold on Amazon

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