Idlers, Backside Belt Tensioning

Brand :
MISUMI
Caution
Product Description
Idlers, Backside Belt Tensioning
Idlers for timing pulleys are an economy item, The price is cheaper than the MISUMI standard product.They offer a wide variety of sizes to choose from.
[Feature]
● Belt Width Used (mm.) : 4, 6, 10, 15, 20 and 25
● Belt Width Used (Inch.) : 0.19, 0.25, 0.31, 0.37, 0.5, 0.75 and 1
● Bearing Position : Central Single Bearing and Both Sides Bearing
● Shaped : With or without flanged
● Material :
Body and Flange : Aluminum Alloy
Bearing : Steel
● Surface treatment : Clear Anodized
[Application]
Idlers for timing pulleys are used to maintain proper tension and alignment in timing belt systems
This series of products is expected to be closed from December 2025, while stocks last. Recommend similar product series,pleaseClick

The bearings are press-fitted. *Bearing accuracy JIS B1514 level 0 (before press-fitting)

Product Overview
As a mechanism for transmitting the rotational power generated by the motor, timing pulleys, timing belt idlers and timing belts are usually widely used in design.
During the actual assembly process, the timing belt can be tensioned through the back tensioning idler pulley.
During the actual assembly process, the timing belt can be tensioned through the back tensioning idler pulley.
Product Features
Feature 1: The idler pulley for back tensioning of MISUMI timing belt can be applied to all toothed belts.
Feature 2: MISUMI timing belt idler pulleys for tensioning the back side do not come into contact with the tooth surface, greatly reducing wear on the teeth.
Feature 3: The idler wheel is used for tensioning the back of the MISUMI timing belt, which will not contact the tooth surface, and the tensioning position can be adjusted at will.
Feature 4: The idler pulley for tensioning the back of the MISUMI timing belt can be installed on the outside of the loose edge close to the pulley to increase the wrap angle of the belt.
Feature 5: MISUMI timing belt idler pulley complies with industry standards, with stable procurement and easy equipment maintenance.
Feature 6: MISUMI timing belt idler pulleys are available in a variety of materials to adapt to various designs and usage environments.
Feature 2: MISUMI timing belt idler pulleys for tensioning the back side do not come into contact with the tooth surface, greatly reducing wear on the teeth.
Feature 3: The idler wheel is used for tensioning the back of the MISUMI timing belt, which will not contact the tooth surface, and the tensioning position can be adjusted at will.
Feature 4: The idler pulley for tensioning the back of the MISUMI timing belt can be installed on the outside of the loose edge close to the pulley to increase the wrap angle of the belt.
Feature 5: MISUMI timing belt idler pulley complies with industry standards, with stable procurement and easy equipment maintenance.
Feature 6: MISUMI timing belt idler pulleys are available in a variety of materials to adapt to various designs and usage environments.
Dimensional Drawing
Material | Surface Treatment | ||
| main body | Flange | Bearing | |
| Aluminum Alloy | Aluminum Alloy | Steel | Clear Anodized |

The bearings are press-fitted. *Bearing accuracy JIS B1514 level 0 (before press-fitting)Specification Overview

■Dimensional specification table Center bearing type
Dimensions marked with * are only available for C-AFDF
■Dimensional specification table Bearing type on both sides
For detailed sales models, please refer to the MISUMI official website.
Dimensions marked with * are only available for C-AFDF
| Type | outer diameterD | F | A | Applicable belt nominal width | S | Bearing model and size | ||||
Type | Applicable Belt | inch | mm | No. | d | B | ||||
| C-AFBD(no Flange type) C-AFDF(With Flange type) | 9 | 20 | 25 | 5 | - | 040 | 2.5 | 695ZZ | 5 | 4 |
| 25 | 30 | |||||||||
| 10 | 6 | 019 | - | 696ZZ | 6 | 5 | ||||
| 11 | 7 | - | 060 | 3 | ||||||
| 11.5 | 7.5 | 025 | - | 3.25 | ||||||
| 14 | 30 | 35 | 9 | 031 | 4 | 698ZZ | 8 | 6 | ||
| 15 | 11 | 037 | 100 | 4.5 | ||||||
| 16 | 40 | 48 | 4 | 6000ZZ | 10 | 8 | ||||
| 19 | 30 | 36 | 14 | 050 | - | 6.5 | 698ZZ | 8 | 6 | |
| 35 | 45 | 5.5 | 628ZZ | 8 | ||||||
| C-AFBD(no Flange type) C-AFDF(With Flange type) | 22 | 35 | 45 | 17 | - | 150 | 7 | 6000ZZ | 10 | 8 |
| *45 | 55 | 6.5 | 6200ZZ | 9 | ||||||
| 26 | 40 | 48 | 21 | 075 | - | 9 | 6000ZZ | 8 | ||
■Dimensional specification table Bearing type on both sides
| Type | NominalModel | outer diameter D | F | A | Applicable belt nominal width | Bearing model and size | ||||
Type | Applicable Belt | inch | mm | No. | d | B | ||||
| C-AFBD(no Flange type) C-AFDF(With Flange type) | 9 | 15 | 15 | 18 | 5 | - | 040 | 675ZZ×2 | 5 | 2.5 |
| 11 | 15 | 15 | 18 | 7 | 060 | 675ZZ×2 | 5 | 2.5 | ||
| 20 | 20 | 25 | 676ZZ×2 | 6 | 3 | |||||
| 11.5 | *15 | 15 | 18 | 7.5 | 025 | - | 675ZZ×2 | 5 | 2.5 | |
| 15 | 25 | 25 | 30 | 11 | 037 | 100 | 688ZZ×2 | 8 | 5 | |
| 19 | 32 | 14 | 050 | - | ||||||
| 30W | 30 | 36 | ||||||||
| 22 | 25 | 25 | 32 | 17 | - | 150 | ||||
| 35W | 35 | 45 | 6000ZZ×2 | 10 | 8 | |||||
| 26 | 40W | 40 | 48 | 21 | 075 | - | ||||
| *45W | 45 | 55 | 6201ZZ×2 | 12 | 10 | |||||
| 27 | 60 | 60 | 67 | 22 | - | 200 | ||||
| 32 | 45 | 45 | 55 | 27 | 100 | 250 | ||||
| 65 | 65 | 74 | ||||||||
| 37 | 55 | 55 | 67 | 32 | - | 300 | ||||
| 45 | 70 | 70 | 80 | 40 | 150 | - | 6202ZZ×2 | 15 | 11 | |
| 49 | *60 | 60 | 67 | 44 | - | 400 | ||||
For detailed sales models, please refer to the MISUMI official website.Dimensions marked with * are only available for C-AFDF
Usage Method
| Usage case diagram | How to use the idler pulley for back tensioning of timing belt |
![]() | When using a back tension idler on the outside, the pulley diameter should be selected to be at least 20% larger than the smallest pulley diameter in the product catalog. ① When using tensioning idler pulleys on the outer side, they should be positioned near the larger pulley. ②The bending angle of the machine belt should be greater than 140#. ③ The tension idler should use a flat pulley without protrusions. ④Do not use the idler pulley for back tensioning of polyurethane belts. |
Example of Use

■Mechanism name
Belt Tension Device (Manual)
■Mechanism function
1. Move the roller on the adjustment side and tighten it while the conveyor belt is open.
2. For multiple driving applications, the engagement rate can be improved by setting the roller in the middle position.
■Function of the Timing Belt Idler
1. Fix the belt assembly distance with a timing belt idler
At the same time, the auxiliary polyurethane roller tensions the belt.
For details, please clickBelt tension device case
Belt Tension Device (Manual)
■Mechanism function
1. Move the roller on the adjustment side and tighten it while the conveyor belt is open.
2. For multiple driving applications, the engagement rate can be improved by setting the roller in the middle position.
■Function of the Timing Belt Idler
1. Fix the belt assembly distance with a timing belt idler
At the same time, the auxiliary polyurethane roller tensions the belt.
For details, please clickBelt tension device case
Related Industries
| Semiconductor | Automotives | Smartphones | ||
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| Medical | Electronic & Electrical Appliances | Robotics | ||
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Precautions
① Do not use the idler pulley for back tensioning on polyurethane timing belts.
Related Documents
Timing Belts, Timing Pulleys, Idler Technical Information
①Selection of timing pulleys and timing belts, tensioning force and other data (transmission)。
②timing pulley and timing belt selection data, tensioning force and other data (transmission)。
③The main causes and countermeasures for damage, breakage, abnormal noise, etc. of the timing belt。
④Reference materials on timing belt replacement intervals.。
⑤Timing pulley, idler dimensional tolerance information。
①Selection of timing pulleys and timing belts, tensioning force and other data (transmission)。
②timing pulley and timing belt selection data, tensioning force and other data (transmission)。
③The main causes and countermeasures for damage, breakage, abnormal noise, etc. of the timing belt。
④Reference materials on timing belt replacement intervals.。
⑤Timing pulley, idler dimensional tolerance information。
Related Products
| Idler pulley for flat belt Width (T) 6~32mm | Flat belt for general use | High torque timing pulley S2M type | ||
![]() | ![]() | ![]() | ||
| Representative model: HBG15-6 | Representative model: HBLT350-4.23 | Representative model: HTPA48S2M040-B-N10 | ||
| Advantages: short delivery time, various types | Advantages: Freely specify the size | Advantages: short delivery time, various types |
Material
Surface Treatment
outer diameter
Applicable Belt








