Bearing inner diameter of a large idler wheel?

[BlueGoose]

What is the inner bearing diameter of larger derailleur idlers? Is it 8mm or larger? I see they have a large bearings, then static reducers are on both sides to fit the derailleur.

I have a recumbent and it has plastic idlers to guide the long chain below the frame. The bolt through the idlers is 8mm. The stronger motor will chew up the plastic idler. I hope to fit metal idlers, something like 16T or 20T or similar.

 

[amberwolf]

I guess it depends on the specific jockey wheel. This one is a fair bit larger bearing than you're probably looking at, for instance

absoluteBLACK HOLLOWcage reimagines wild, low friction rear derailleur pulleys

Absolute Black's new Hollow Cage may be a truly revolutionary bike upgrade with a lightweight single-sided cage & giant low friction pulleys!

bikerumor.com

For the jockey wheels meant to replace existing wheels in existing derailer cages, their bearing IDs are probalby going to be the same as the IDs of the bushings in the wheels they would replace, like these

Product KCNC 11T Jockey Wheels - Stainless Steel Bearing

KCNC replacement Jockey Wheels in 6 anodised colours. Beautifully made from anodised cnc machined 7075 alloy with fully.

clee-cycles.co.uk

I dont' recall the size and didnt' see it in a quick google, but thsi page

Product KCNC Alloy Jockey Wheel Bolts

Anodised alloy jockey wheel bolts for rear derailleurs. Will fit current models of Campagnolo and Shimano road and mtb .

clee-cycles.co.uk

for bolts for these says they're 5mm, which sounds right.
\

This page

626-2RS (Sram Jockey Wheel)

If your looking for 626-2RS (Sram Jockey Wheel), come to Aire Velo Bearings the UK No.1 bicycle bearing supplier

www.airevelobearings.com

is specifcally for the bearings, and specifies them as 626-2rs, which calls out dimensions of 6 x 19 x 6 mm.
as does this page

626-2RS Mini Ball Bearing 6x19x6 Sealed R1960-2RS 99036

Bearings Direct is your online store for quality and precision products at wholesale prices. Browse our wide selection of bearings and other industrial products to meet your needs.

bearingsdirect.com

But if the wheels you get have pressed-in bearings you can look at sites like BD above and find ones that have the same OD and width, but larger or smaller ID, most likely.

Or if you need a much larger ID than otherwise possible with the bearing, use bushings instead; I'm sure someone has worn those out in these applications, but in the derailers I've had I've worn the teeth off the wheels long before I ever wore the bushings or bolts even on the cheapest stuff I've ever had. I've never had the "good stuff" so dont' know if those fare even better or not.

 

[amberwolf]

BTW, depending on the placment of your idler, if you're able/willing to do the DIY you could use an old rear hub with thread-on freewheel mount as the idler mount, securing the hub to the frame in place of the idler arm/etc., (or securing it to the arm), or even just the flange/threaded section, cutting away the rest of the hub.

Then put a freewheel of your choice on that, singlespeed if it would work, or even a multispeed that has had all the sprockets except the one you want removed, and plates installed either side of it instead.

Since you don't need the ratchet function, you can remove the pawls to eliminate the noise.

 

[PaPaSteve]

Use this link for chain Idlers designed for recumbents

 

[BlueGoose]

Use this link for chain Idlers designed for recumbents

Thank you, T-cycle has excellent products. If a person is not DIY, their products work first time, every time. Their front and rear idlers would be about $300 for both. I hope to find and publish a more manageable DIY solution for myself and others.

 

[BlueGoose]

BTW, depending on the placment of your idler, if you're able/willing to do the DIY you could use an old rear hub with thread-on freewheel mount as the idler mount, securing the hub to the frame in place of the idler arm/etc., (or securing it to the arm), or even just the flange/threaded section, cutting away the rest of the hub.

Then put a freewheel of your choice on that, singlespeed if it would work, or even a multispeed that has had all the sprockets except the one you want removed, and plates installed either side of it instead.

Since you don't need the ratchet function, you can remove the pawls to eliminate the noise.

I could do that. I will first try to locate idlerwheels.

 

[PaPaSteve]

BMX freewheel with the ratchet removed.
This spacer is made from delrin, wood probably works too.
Aluminum cage needs to have minimum clearance to the chain to keep it from jumping off over bumps.

 

[BlueGoose]

BMX freewheel with the ratchet removed.
This spacer is made from delrin, wood probably works too.
Aluminum cage needs to have minimum clearance to the chain to keep it from jumping off over

PaPaSteve, that makes sense. Where can this be obtained? What is the ID of the freewheel?

 

[amberwolf]

All of the standard thread-on freewheels like that are the same ID and threading:
1.375" x 24 tpi

Traditional Thread-on Freewheels

Information on how to rebuild freewheels, which were very common on derailer-equipped bicycles and which offer a great variety of options for sprocket sizes.

www.sheldonbrown.com

You can make the "core" (spacer) with a hole saw. It doesn't matter if the core piece is threaded or not, it just has to be big enough to fill the ID of the FW so it doesn't rattle around on the bolt.

If you can use the whole rear hub off something, you can use it's axle to bolt it to your frame (or whatever bracket mounts to the frame) and leave the bearings intact and the whole hub will spin.

Or you can remove all the bearings and use just part of the hub with the threaded section and part of the core, and use the axle (or a bolt of appropriate size) to attach the hub to frame/bracket, "pinning' the hub so it doesn't spin but hte FW still does.

 

[PaPaSteve]

PaPaSteve, that makes sense. Where can this be obtained? What is the ID of the freewheel?

DIY project . . . correct ?
BMX freewheels can found lots of places including used.
They are available for 1/8" and 3/32" width chains.
A derailleur bike wants the narrow width.
Disassemble the freewheel to remove the ratchet pawls otherwise it will make noise.
Watch out . . . probably 60 small bearings that can pour out all over the place, use a catch pan during the opening.
When done carefully the bearings will stay in place.
The delrin adapter was made on a lathe.
For a home DIY I could imagine drilling a hole in a piece of wood dowel, place a bolt thru it, spin the wood with a drill motor then sand down to a diameter that fits the freewheel.

 

[Papa]

Blue Goose,

Might try: Chain Management and Idlers

They deal w/recumbents and seem to have a number of options

 

[BlueGoose]

Blue Goose,

Might try: Chain Management and Idlers

They deal w/recumbents and seem to have a number of options

Thank you, I did not consider the Hostel Shop! The greenspeed 15T will fit the purpose and it has an 8mm bearing, there are others at that site. I will verify with them the cogs are metal not plastic

 

[BlueGoose]

DIY project . . . correct ?
...
The delrin adapter was made on a lathe.

Yes, DIY. Nice work. I definitely could make a concentric adapter on drill press, good idea.