Belt tension idlers - Types, what is best, where to buy, what to look for, belt length

[Nathraichean]

Hello,

I’ve recently been working on building a better board than my budget boi and have bought the boardnamics precision XL mounts, which are quite long. I have also got some AT wheels with 72T pulleys, and street wheels with 36T pulleys.

This brought up two questions in my mind :

1. How do I figure out the belt length I would need for both pulleys
2. Where the hell do I buy eboard idlers for the mounts and how much longer belts would I need to compensate for the idlers

I’d be thankful for any info on the matters because I practically found none. Seems to be a mystery topic (for the idlers).

Thanks!

[tech.shit]

@Nathraichean

How do I figure out the belt length I would need for both pulleys

Belt length calculator. Many are available through a Google search.they require the tooth count of both the driving and driven pulleys and the center to center distance.

@Nathraichean

Where the hell do I buy eboard idlers for the mounts and how much longer belts would I need to compensate for the idlers

Typically idlers come with mounts that need them. Idlers are usually adjustable as their purpose is to take up the slack of a belt that’s too big.

You can make your own idler by stacking a couple bearings on a bolt and adding a washer to space it away from the mount.

[fessyfoo]

@tech.shit

Idlers are usually adjustable as their purpose is to take up the slack of a belt that’s too big.

“Actually” purpose is to increase the number of teeth engaged on the pinion.

[tech.shit]

I figured that was just a beneficial side effect

[Jley]

You can simply just draw it up on a sheet of paper, use a piece of string to trace the path and measure length if the shape is to complex to figure with basic math and make the adjustments to suit the available belt sizes. Using basic compass set from the office shop.

The idler pulley allows for maximal power transfer and breaking by wrapping the belt around the drive gear for maximal teeth engagment therefore no slipping either. I think it is hard to beat trampa’s OBD system for price . They solved the entire problem and have a quick adjuster tensioner screw. I use them on one of my street cruisers. OPEN BELT DRIVE Mountainboard Motor Mounts

[Mikenopolis]

I’m watching Daniel Kwan’s video on the Parsec Aero. I’ve been running my boards with idlers for year and have them on the top side and with more belt tension than his board which has the idler on the bottom.

Have I been doing it wrong? Why is his belt so loose, I feel like the belt would skip under hard acceleration or braking.

[rafaelinmissouri]

You can have them really loose with idlers…
Mine are not quite like his. But lots of slack…

Way, way more than when you don’t have idlers

[Egtscs]

@Mikenopolis

his board which has the idler on the bottom.

@RideParsec

We intentionally placed the idler on the “wrong” side. It’s more of a preferred side to be fair, and we had good reasons. First, the Aero Pro is a street board using street wheels, placing the idler on the driving side will make it easier for clearing the debris. Second, the Aero Pro isn’t 200A/side, we have only 20/25Amps running per motor and it’s not a lot of load. And lastly, the drivetrain on the Aero Pro was designed to decouple the motor and the wheel, in order to improve coasting.

It sounds like an unusual design choice.

@Mikenopolis

Have I been doing it wrong?

No, if anything parsec is doing it “wrong”

@RideParsec

With the idler on the top-side, the loose belt is more likely to be damaged by the road and might even cause a safety risk when it gets caught on something.

The aero pro seems to value it’s “longboard feel” as a high priority, part of that feeling is being able to free roll like a longboard, which requires really loose belts, having belts that loose leaves them at a greater risk of damage without the belt being pulled away from the ground by the idler.