Sram Eagle GX 1 x 12 Jockey Wheel Bearings

[Quagga]

You press them in from the other side.

The bearings are pressed in at the factory. I've replaced the bearings twice in the 10,000odd km the derailleur has seen. The wheels still run straight and true and the bearings last about 3000-4000km 

Both sides look the same? it has a little lip to hold bearing in place.

 

I am not saying you can not do it, I am saying it is not designed to be done the way you do it.

 

Why is it necessary to replace (upgrade) the cage? Not sure if there is an XX1 price associated with it. Is it possible just to do the jockey wheels?

All the cages are the same, xx1 and x0 is carbon and the others steel

[DieselnDust]

Why is it necessary to replace (upgrade) the cage? Not sure if there is an XX1 price associated with it. Is it possible just to do the jockey wheels?

 

The Distributor doesn't supply the Jockey pulley wheels alone due to the cost of the wheels being only sightly less expensive than replacing the whole jockey pulley cage assembly (Two Wheels and inner cage plate). 

Hence we've (many shops, and home mechanics like myself) have come up with replacing the bearings.

Csixx Jockey pulley wheels for Eagle = R1100

XX1 Jockey Pulley cage assembly = R1050

GX Eagle pulley cage assembly = R700

Set of Jockey pulley wheels for SRAM Eagle (GX)= R650-00

pair of 626RS2 Enduro bearings = R180-00 (probably more expensive than it needs to be as I'm sure solid Oil bearings from Bearingman would be similar price)

 

The plastic wheels don't really wear out (well after about 10,000km they do start to look worse for wear) but the bearings, especially the lower tensioning idler bearing sees a lot of dirt due to it being closer to the ground and the amount of crud that gets stuck on that wheel.

[DieselnDust]

Both sides look the same? it has a little lip to hold bearing in place.

 

I am not saying you can not do it, I am saying it is not designed to be done the way you do it.

 

All the cages are the same, xx1 and x0 is carbon and the others steel

 

The lip is soft. All it does is close the gap between the edge of the spacer to create a smaller gap for dirt to get through. Other than that it has no function.

 

I get it you don't want to replace the bearings. That's your choice. If you want want new pulley wheels that's up to you. Its your money.

The original question was around replacing the bearings. That's been answered

[slickjay007]

You press them in from the other side.

The bearings are pressed in at the factory. I've replaced the bearings twice in the 10,000odd km the derailleur has seen. The wheels still run straight and true and the bearings last about 3000-4000km 

 

Great news! something i learn't today.

[MudLark]

Diesel, what grease to use when the re-lubricating the bearings? Presumably one wants something relatively light. Vaseline has often been recommended but doesn't seem to last. I see some people recommend running them dry – though not exactly a high-speed bearing so I suppose won't overheat but not sure whether that is a good idea either. One is tempted to may be good bit of graphite dust in them and see how that goes.

[Quagga]

You press them in from the other side.

The bearings are pressed in at the factory. I've replaced the bearings twice in the 10,000odd km the derailleur has seen. The wheels still run straight and true and the bearings last about 3000-4000km 

When pressing the bearing in you are going to damage the lip

 

Both sides look the same with the same lip so there is no other side to press it in from 

 

See the pics here, both side look the same

As I said, it is molded in and you said it is pressed in. But it is molded in Right?

one side 

other side

[DieselnDust]

When pressing the bearing in you are going to damage the lip

 

Both sides look the same with the same lip so there is no other side to press it in from 

 

See the pics here, both side look the same

As I said, it is molded in and you said it is pressed in. But it is molded in Right?

one side 

IMG_0122.JPG

other side

IMG_0123.JPG

 

 

it is NOT moulded in place. please explain how you would design the mould to injection mould hot thermoplastic around a bearing with a rubber seal....

 

The lip is not deep, its soft, when you press the bearing in you don't destroy the lip (at least if the bearing is pressed in carefully).

 

In the factory the parts are hot water washed, this also expands the size of the whole and the bearing is pressed in. 

 

My technique for pressing in the bearings is simple. I hot water wash the wheel (after removing it from the derailleur) in some boiling water. Then place the wheel in a support (wooden block) with a hole that's just slightly bigger than the bearing. Then using a drill press with a tool I made (basically a shaft with a shoulder the diameter of the bearing, I place the new bearing on the tool and align the wheel and press.

Old bearing pops out the bottom, new bearing is in place and 0.5mm deep into the wheel.

 

Is the lip destroyed? After the first replacement, no. After the 2nd yes its damaged. Does this impede the functioning of the wheel? Not as far as I can tell. This is the only criteria that matters to me.

There does come a time for replacement, nothing lasts forever.

 

Its not wobbling on the shaft after over a 1000km since the 2nd replacement so the wheel has not slipped on the bearing( Remember to fit the bearing with retaining compound).

 

Next time I'l get new wheels because the current ones are now obviously worn.

 

 

I really not following why you harp on an aspect that has no bearing on the functioning of the pulley wheel.

Edited July 1, 2020 by DieselnDust

[Quagga]

Diesel, what grease to use when the re-lubricating the bearings? Presumably one wants something relatively light. Vaseline has often been recommended but doesn't seem to last. I see some people recommend running them dry – though not exactly a high-speed bearing so I suppose won't overheat but not sure whether that is a good idea either. One is tempted to may be good bit of graphite dust in them and see how that goes.

If you run them dry and get the slightest water, the stop turning.

 

You want a light grease, like the white lightning crystal grease else they drag and hold onto the chain

[Quagga]

it is NOT moulded in place. please explain how you would design the mould to injection mould hot thermoplastic around a bearing with a rubber seal....

 

The lip is not deep, its soft, when you press the bearing in you don't destroy the lip (at least if the bearing is pressed in carefully).

 

In the factory the parts are hot water washed, this also expands the size of the whole and the bearing is pressed in. 

 

My technique for pressing in the bearings is simple. I hot water wash the wheel (after removing it from the derailleur) in some boiling water. Then place the wheel in a support (wooden block) with a hole that's just slightly bigger than the bearing. Then using a drill press with a tool I made (basically a shaft with a shoulder the diameter of the bearing, I place the new bearing on the tool and align the wheel and press.

Old bearing pops out the bottom, new bearing is in place and 0.5mm deep into the wheel.

 

Is the lip destroyed? After the first replacement, no. After the 2nd yes its damaged. Does this impede the functioning of the wheel? Not as far as I can tell. This is the only criteria that matters to me.

There does come a time for replacement, nothing lasts forever.

 

Its not wobbling on the shaft after over a 1000km since the 2nd replacement so the wheel has not slipped on the bearing( Remember to fit the bearing with retaining compound).

 

Next time I'l get new wheels because the current ones are now obviously worn.

 

 

I really not following why you harp on an aspect that has no bearing on the functioning of the pulley wheel.

Easy dude. I thought we were discussing something?

 

You said press it in from the other side, I said both side look the same so it should not matter then what side you press it in from. Right?

[DieselnDust]

Easy dude. I thought we were discussing something?

 

You said press it in from the other side, I said both side look the same so it should not matter then what side you press it in from. Right?

It matters not which side you press it in from.

But one side does expose more of the bearing outer race. This is the side I press the new bearing into, If you are concerned with preserving the lip then press the old bearing out via the side with the lip that appears to be smaller. Press the bearing ot via the inner race. Flip the wheel around and press the new bearing in Via its outer race. Like I said, I'm not concerned with the lip at all so I press the old out with the new following right behind it

[Quagga]

It matters not which side you press it in from.

But one side does expose more of the bearing outer race. This is the side I press the new bearing into, If you are concerned with preserving the lip then press the old bearing out via the side with the lip that appears to be smaller. Press the bearing ot via the inner race. Flip the wheel around and press the new bearing in Via its outer race. Like I said, I'm not concerned with the lip at all so I press the old out with the new following right behind it

I have an old set here, and I am going to try what you suggested.

 

I

[Schnavel]

You press them in from the other side.

The bearings are pressed in at the factory. I've replaced the bearings twice in the 10,000odd km the derailleur has seen. The wheels still run straight and true and the bearings last about 3000-4000km 

 

Surely you don't need to do it so regularly? That's not that much distance.

 

Would this only apply to mtb jockey wheels?

[ChrisF]

Surely you don't need to do it so regularly? That's not that much distance.

 

Would this only apply to mtb jockey wheels?

 

My Scott had less than 1 000km on it at the time.  NO mud rides, lots of dusty trails ....  Night before an event I did the normal wash and lube ....  Actually went a bit further and removed the rear wheel and cleaned the chain.

 

Somehow I managed to let the chain "slip" over the bottom jockey wheel ... getting the narrow-wide out of sink.  I immediately saw it, pulled the chain away and moved the jockey wheel over one tooth .... WHAT !!!  The jockey wheel was NOT turning smoothly !!! 

 

Fast forward - the bearings was grinding from all the dust in it !!

 

 

No choice but to remove the dust covers, wash out the much, regrease, and re-fit.

 

 

Thankfully the bearings were smooth after the regrease.  BUT, lesson learnt !!  Even mild dusty rides kills these bearings !!!  Apparently this is very common, and these bearings should be much higher on the maintenance list .... Scary bit, once that bearing binds it can cause serious damage to some very expensive parts.

[JA-Q001]

You Guys do understand that the lip isn't moulded into the Jockey wheel. To create a fast working, low cost mould would be impossible if such a lip was moulded in. It is formed over time.

 

The hole start as one size right through, about 0.5 mm smaller in diameter than the bearing. After the bearing has been pressed in, probably on a automatic production line, the plastic deforms over time and forms its own lip on the overhang.

 

The only thing that can happen after repeated bearing replacements is that the plasticity of the Plastic gets harder and the bearing becomes a slide fit instead of an interference fit. AT this time the wheel should be worn enough to warrant replacement.

[DieselnDust]

Surely you don't need to do it so regularly? That's not that much distance.

 

Would this only apply to mtb jockey wheels?

 

The bearing gets very dirty very quickly. The tensioner wheel bearing wears the fastest. Guide pulley wheel bearing is usually good for the 3000km-4000km. 

With the trend to 1x and bigger pulleys (helps make the extreme derailleur range possible) there is a lot more side loading on the bearing at the extremes and the lower pulley bearing therefore has to work in a misaligned orientation. Its one of the very bad design attributes of 1x drivetrains. The lower pulley bearing really should be a high clearance unit and of the self aligning type but there isn't space for a self aligning unit.

So you'll ask : but won't a self aligning bearing negatively affect the shifting?"

No not by much since it is the guide pulley at the top that handles all the shifting load.

 

 

If one was running Shimano XTR or Dura Ace then the lower pulley bearing wear is not so obvious because the pulley wheel is smaller so there isn't as much side loading on the bearing. The bearings are also covered by a spacer that doubles up as a labyrinth seal so the bearing doesn't get as dirty. Shimano has this design patented hence no one else in the bike industry copies it. The reduction in side loads on the load pulley in 2x drivetrains also ensure longer life for the bearing.

 

 

 

 

My Scott had less than 1 000km on it at the time.  NO mud rides, lots of dusty trails ....  Night before an event I did the normal wash and lube ....  Actually went a bit further and removed the rear wheel and cleaned the chain.

 

Somehow I managed to let the chain "slip" over the bottom jockey wheel ... getting the narrow-wide out of sink.  I immediately saw it, pulled the chain away and moved the jockey wheel over one tooth .... WHAT !!!  The jockey wheel was NOT turning smoothly !!! 

 

Fast forward - the bearings was grinding from all the dust in it !!

 

 

No choice but to remove the dust covers, wash out the much, regrease, and re-fit.

 

 

Thankfully the bearings were smooth after the regrease.  BUT, lesson learnt !!  Even mild dusty rides kills these bearings !!!  Apparently this is very common, and these bearings should be much higher on the maintenance list .... Scary bit, once that bearing binds it can cause serious damage to some very expensive parts.

 

 

Yes regreasing will extend the life but generally it won't double the life due to the main wear coming from the way the bearing race is worn by the side loading of the bearing.

I consider the tensioner wheel bearing to be an expendable unit. There's just no getting way from it wearing out  relatively quickly. SKF MRTX soild oil bearings may last longer because the design will handle the dirt a lot better but the bearing will still wear as the result of being loaded and run off its design load axis for extended periods. Its still a lot cheaper than a new cage assembly and at least removes the maintenance 

 

 

 

You Guys do understand that the lip isn't moulded into the Jockey wheel. To create a fast working, low cost mould would be impossible if such a lip was moulded in. It is formed over time.

 

The hole start as one size right through, about 0.5 mm smaller in diameter than the bearing. After the bearing has been pressed in, probably on a automatic production line, the plastic deforms over time and forms its own lip on the overhang.

 

The only thing that can happen after repeated bearing replacements is that the plasticity of the Plastic gets harder and the bearing becomes a slide fit instead of an interference fit. AT this time the wheel should be worn enough to warrant replacement.

 

I agree 110%

[Schnavel]

The bearing gets very dirty very quickly. The tensioner wheel bearing wears the fastest. Guide pulley wheel bearing is usually good for the 3000km-4000km. 

With the trend to 1x and bigger pulleys (helps make the extreme derailleur range possible) there is a lot more side loading on the bearing at the extremes and the lower pulley bearing therefore has to work in a misaligned orientation. Its one of the very bad design attributes of 1x drivetrains. The lower pulley bearing really should be a high clearance unit and of the self aligning type but there isn't space for a self aligning unit.

So you'll ask : but won't a self aligning bearing negatively affect the shifting?"

No not by much since it is the guide pulley at the top that handles all the shifting load.

 

 

If one was running Shimano XTR or Dura Ace then the lower pulley bearing wear is not so obvious because the pulley wheel is smaller so there isn't as much side loading on the bearing. The bearings are also covered by a spacer that doubles up as a labyrinth seal so the bearing doesn't get as dirty. Shimano has this design patented hence no one else in the bike industry copies it. The reduction in side loads on the load pulley in 2x drivetrains also ensure longer life for the bearing.

 

 

 

 

 

 

Yes regreasing will extend the life but generally it won't double the life due to the main wear coming from the way the bearing race is worn by the side loading of the bearing.

I consider the tensioner wheel bearing to be an expendable unit. There's just no getting way from it wearing out  relatively quickly. SKF MRTX soild oil bearings may last longer because the design will handle the dirt a lot better but the bearing will still wear as the result of being loaded and run off its design load axis for extended periods. Its still a lot cheaper than a new cage assembly and at least removes the maintenance 

 

 

 

 

I agree 110%

 

Your logic makes sense to me, from a mechanical perspective. That being said, I do my own bike maintenance, and other than a small application of grease to the jockey wheel bearings, my 1x11 XX1 rear derailleur has around 7000km on it and the bearings are running smoothly, hence my original question.

 

Definitely something to remember when it comes to replacing the bearings.