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Caterpillar 307 308 E70 Bottom Roller 127-3806

Cat 307C 308CCR Bottom Roller
Rubbertrax
Caterpillar 307 308 E70 Bottom Roller 127-3806
Buy aftermarket bottom roller part number 127-3806 for your Cat 307-E2, 308-E2CR, and E70/B online and save versus going to your Cat dealer. This is the outside guide type roller as pictured. It is common to have a combination of some inside guide rollers with these outside guide rollers so please verify your exact roller prior to ordering online. If you have the inside guide roller part number 127-3807 we also stock that option for sale online.
SKU: 127-3806
Weight: 36 lbs
Make: Cat
Shipping: Fast and Free!
Price: $230.00

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This is the aftermarket bottom roller for the following Caterpillar mini excavators. This is the outside guide type roller. Some models may require the inside guide type with the center flange dropping inside the track guide. This outside guide roller type travels along the track guide system as the outside flanges prevent the track from de-tracking.


This bottom roller is known to fit the following models:


Alternate Part Numbers

  • Caterpillar Dealer Part Number: 127-3806, replaces BA4310800

Alternate Models

This bottom roller (127-3806) is known to fit:

  • Caterpillar® 307
  • Caterpillar® 307A
  • Caterpillar® 307B
  • Caterpillar® 307C Must Verify Serial
  • Caterpillar® 307D
  • Caterpillar® 307E
  • Caterpillar® 307E2
  • Caterpillar® 307E FB (S/N H1Y)
  • Caterpillar® 307E2 FB (S/N CE2, KC9)
  • Caterpillar® 308
  • Caterpillar® 308C
  • Caterpillar® 308CCR Must Verify Serial
  • Caterpillar® 308D
  • Caterpillar® 308E
  • Caterpillar® 308E2
  • Caterpillar® 308E2CR (steel track models)(S/N TMX, FJX)
  • Caterpillar® 308E2CR VAB (steel track models)(S/N W8S)
  • Caterpillar® 309
  • Caterpillar® E70
  • Caterpillar® E70B
  • Caterpillar PM465 Paving Machine (20)

Outside Guide Rollers

Please check your undercarriage completely as you may have both inside guide and outside guide type rollers on the E70. Always replace your rollers with the same type in the same tack frame positions.

It is always important to change your undercarriage parts and rubber tracks at the same time to maximize the life span of the tracks and parts and get the optimal wear.


The Cat 307 D/C/B and 308D/C/B have a different number of bottom rollers depending on your serial prefix. You may have eight or ten rollers. The serial prefix with the quantity of rollers per machine:

  • 8 Rollers Per Serial Breaks: (2FL 2PM 2WM)
  • 8 Rollers Per Serial Breaks: (9ZL AFB)
  • 10 Rollers Per Serial Breaks: (CRW BNE BCM BAJ 4RW)
  • 10 Rollers Per Serial Breaks: (5CW 6KZ 7DZ JPS)
  • 10 Rollers Per Serial Breaks: (HAS GBT FYC ECT DSG 3YS)