[SirChomps-a-Lot]

So I isolated the creak in my suspension to the top shock bushing. I threw some grease on the axle-pin that goes through the bushings, but not on the interface between the bushings and the sleeve in the shock eyelet. This seems to have fixed the creak.

It occurs to me that I don't understand how this whole bushing thing is supposed to work -- where does the rotation happen? As far as I can tell when I compress the suspension, there is some rotation happening in the interface between the bushing and the shock eyelet, and some rotation happening between the thru-pin and the inside of the bushing. Most of the rotation, though, is coming from the interface between the thru-pin and the inside of the bushings. This also means that the bushings are rotating and rubbing against the inside of the rocker plates.

Does someone have a diagram of all the parts involved in connecting a shock eyelet to a rocker plate, and how they are supposed to work?

 

[SirChomps-a-Lot]

Digging around, I've found some reports of sundays wearing grooves in the upper shock pin, which makes sense to me, given where the rotation is happening on my bike. (my bike is a 6-point, btw) Is this supposed to happen?

 

[Udi]

The rotation (and therefore wear) should occur between the reducer (generally a 12.7mm OD shaft, with a 8 or 10mm ID for the shock bolt to go through), and the DU bushing (a teflon/polymer coated bushing pressed into the shock eyelet.

That is the only place movement should occur. Wear in other areas usually indicates problems.

 

[SirChomps-a-Lot]

The rotation (and therefore wear) should occur between the reducer (generally a 12.7mm OD shaft, with a 8 or 10mm ID for the shock bolt to go through), and the DU bushing (a teflon/polymer coated bushing pressed into the shock eyelet.

That is the only place movement should occur. Wear in other areas usually indicates problems.

That's what I thought. So I have problems: my rotation is happening between the reducer and the shock bolt. It sounds this is a common problem on DW-link ironhorse bikes.

Any solutions anyone?

edit: so I took it apart again and the rotation I was seeing was between the reducer and these two spacers on either side of the shock eyelet. I think the small amount of wear on the shock bolt I'm seeing is from the actual rocker plates.

I actually think it should be good to go...

Bushings still weird me out though... metal rubbing on metal.

 

[4130biker]

Bushings still weird me out though... metal rubbing on metal.

The rotation (and therefore wear) should occur between the reducer... and the DU bushing (a teflon/polymer coated bushing pressed into the shock eyelet.

That is the only place movement should occur. Wear in other areas usually indicates problems.

It should not be metal on metal, if working properly, just like Udi explained

 

[SirChomps-a-Lot]

It should not be metal on metal, if working properly, just like Udi explained

ok, took it apart AGAIN and put it back together without the spacers on either side of the shock eyelet.

There is definitely no rotation happening between the DU bushing and the reducer! The reducer is a super-tight fit in the DU bushing as well.

Does this mean my reducer is too big and I need to get another one?

 

[miuan]

You can't get it to rotate with bare hand. Once installed though, it WILL rotate. If it doesn't, the rotation must happen between bolt and reducer. Now when you cycle your suspension, is there a difference in perceived shock spring rate between normal operation and when the bolt is loose? If not, your bushing does rotate.

 

[4130biker]

It's one of those things that would be easier to help you with in person. But, I think you should try tightening those pivot bolts up to the specified torque first.
Good idea watching it work without the spacers-- try that after you've torqued the bolts.
If the bushing still doesn't rotate against the pin, I would have someone look at it with you, because rotating against the rocker arms is just going to mess up the arms and potentially cause problems with the bolts staying tight.

Also, the bushing should be a fairly tight fit with the pin.

 

[YoPawn]

If the reducers don't spin (by hand) inside a DU bushing that has some rides on it, it may be too tight. Sure you can make it rotate by tightening the bolt, but your suspension is just not working correctly if there is that much stiction.

I don't know how you would make it run a little smoother, other than greasing the DU itself (which doesn't help much if it is tight to begin with) or going to Enduro Needle Bearings when more sizes come out.

I know a lot of people would argue this with me, but I am a firm believer that if it doesn't rotate at all by hand, it is too tight and will result in reduced suspension sensitivity and possibly screwed up seals in the shock shaft from transferring the twist into the shock body.

I have rarely found any DU bushings that have no play, yet spin by hand. One of the most idiotic designs still left on our bikes.

 

[buildyourown]

Let me guess, you have the 2 piece alum style bushing hardware vs the 3 piece with the hardened steel pin? Scare up the later. TF tuned used to make them. Many shops can get them.

These guys are also selling kits that replace the whole mess with needle bearing
http://www.enduroforkseals.com/

To my knowledge, Specialized is really the only manufacturer to properly address this. They eliminate the bushing all together and use their own hardware.

 

[Dogboy]

Check posts #2219 and #2220 in the Sunday sticky thread. This might be your issue. It sounds like the upper link isn't pinching the reducer sufficiently. Good luck.

 

[DirtyMike]

Let me guess, you have the 2 piece alum style bushing hardware vs the 3 piece with the hardened steel pin? Scare up the later. TF tuned used to make them. Many shops can get them.

These guys are also selling kits that replace the whole mess with needle bearing
http://www.enduroforkseals.com/

To my knowledge, Specialized is really the only manufacturer to properly address this. They eliminate the bushing all together and use their own hardware.

Or.... You can call Marzocchi and order whatever size you need

 

[SirChomps-a-Lot]

I am pretty sure you are refering to the same issue/fix that I had....

For me, the uderside of the flat head bolt was bottoming on the pin before it could fully clamp the upper links to the shock reducers.

I removed the upper pin and carefully took a 3/8" (IIRC) drill bit and opended up the countersink in the open end of the pin. This allowed the bolt to thread in further, clamping the upper links.

Interesting... I will try this and report back. I definitely have it torqued up without the spacers (it's the 3 piece steel sleeve and 2 alu spacers). I know the reducer isn't moving in the DU bushing because I drew a line on each with a sharpie and the lines stay lined up as I cycle the suspension.

 

[SylentK]

My shock pins on my Sunday have always worn as the OP's. Even w/ stock 2005 or new 2007 hardware. I've just been replacing the pins as they wear. The linkage is tight up until the pins start wearing too much. My experience anyway...

 

[SirChomps-a-Lot]

This is bollocks, dude. Screw bushings... I'm looking into getting it hooked up with some needle bearings.

 

[SirChomps-a-Lot]

Contacted enduroforkseals about getting this beyotch sorted out. Looks like there's a kit coming that will work for the sunday as well (!).

rejoice!

Thanks for contacting us. It is definitely do-able, but will take a more comprehensive kit. We are working on it right now as it will cover the Sunday, 7-Point, and MKIII frames as well. I'm guessing 2-3 weeks.

Best regards,

Chris

Chris Streeter
Real World Cycling, LLC
Chris@enduroforkseals.com
http://www.enduroforkseals.com/
Phone: (877) ENDURO-1 (363-8761)

 

[roel_koel]

This is bollocks, dude. Screw bushings... I'm looking into getting it hooked up with some needle bearings

fair point

today, I replaced another DU bush on a Orange Five

yesterday, I replaced another DU bush on a Specialized 2004 Enduro FSR

I seem to do alot of DU replacement.....for my customers!


I've seen the needle roller bearing for the Unobtanium titanium spring system, which apparently reduces friction when the spring compresses (I read this is common on MX bikes for many years..)

the DU on MTB shock mounting does seem somewhat crude, yet this mountaing point is very important to the overall suspension performance?

 

[- seb]

I got the heavy-duty kit from TF, no problems at all any more.

 

[YoPawn]

This is bollocks, dude. Screw bushings... I'm looking into getting it hooked up with some needle bearings

fair point

today, I replaced another DU bush on a Orange Five

yesterday, I replaced another DU bush on a Specialized 2004 Enduro FSR

I seem to do alot of DU replacement.....for my customers!


I've seen the needle roller bearing for the Unobtanium titanium spring system, which apparently reduces friction when the spring compresses (I read this is common on MX bikes for many years..)

the DU on MTB shock mounting does seem somewhat crude, yet this mountaing point is very important to the overall suspension performance?

If there is any rotation on the eyelets then it is a noticeable spot to free up the suspension. I noticed a huge difference when switching my buddy's Trance X to needle bearings.

I would imagine lighter weight bikes see more of a benefit, since they do not have the same weight to overcome the stiction on their own.

 

[Muttely]

When replacing bushings witgh needle bearings, do you need one at each end to get max effect?

 

[SirChomps-a-Lot]

When replacing bushings witgh needle bearings, do you need one at each end to get max effect?

Depends on the bike. The more rotation at the eyelet, the more difference needle bearings will make.

For sunday/6point, they're saying the lower eyelet isn't that big of a deal, but I will probably get it replaced anyway when they come out with a kit.

 

[Muttely]

It'd be for a sunday, i can get these from BETD for £15 a pop including pin, so i think ill just grab 2 anyway.

 

[Udi]

Contacted enduroforkseals about getting this beyotch sorted out. Looks like there's a kit coming that will work for the sunday as well (!).

rejoice!

That's really interesting, I emailed him about it. Mostly because I can't see how it would physically work (assuming 07+ sundays etc) unless he machines new <10mm shock pins.

With the stock 10mm shock bolt/pin, and 14mm eyelet ID sans DU bushing (eg. Fox/Vivid), you only have 4mm of diameter (2mm of radius) left to fit both bearing AND appropriate sleeve to act as inner race for bearing. So it's physically impossible unless you make up a shock pin with smaller OD in the centre (eg. 8mm).

 

[davep]

Interesting... I will try this and report back. I definitely have it torqued up without the spacers (it's the 3 piece steel sleeve and 2 alu spacers). I know the reducer isn't moving in the DU bushing because I drew a line on each with a sharpie and the lines stay lined up as I cycle the suspension.

Try this (it is my quote IIRC).... it made all the difference in my Sunday. I have heard from other Sunday owners that had the same issue that was 100% solved with the same procedure.

As for all the plain bearing hate....if you were to actually look at the load, rotation, and possible contamination, they make a LOT of sense. There are definate down sides to needle bearings (no seals, lube=contamination, galling, notching, rust, etc)...anyone who owned an older DHR in a wet climate will be well aquainted with this.

If the mounting hardware is correctly designed, bushings are a very good choice and very appropriate for the design.

 

[Udi]

The top pivot on the sunday has a lot of rotation (and a lot of other bikes are plagued with the same thing) and IMO it would benefit from a needle bearing.

There are plenty of downsides to the bushing in this application as well - namely added stiction, and increased wear/replacement intervals. Over 3 years of frame ownership I've replaced countless upper shock eyelet bushings.

In this specific application, the downsides you mentioned are actually decreased in severity. More rotation = less galling/notching + more evenly spread wear, area not prone to mud/dirt = reduced contamination/rust etc.

Just my take on it. I'd happily try it, and have already made my own 8mm conversion so I can. I just got a reply from Chris@Enduro and he is doing the exact same thing.

 

[SirChomps-a-Lot]

Try this (it is my quote IIRC).... it made all the difference in my Sunday. I have heard from other Sunday owners that had the same issue that was 100% solved with the same procedure.

As for all the plain bearing hate....if you were to actually look at the load, rotation, and possible contamination, they make a LOT of sense. There are definate down sides to needle bearings (no seals, lube=contamination, galling, notching, rust, etc)...anyone who owned an older DHR in a wet climate will be well aquainted with this.

If the mounting hardware is correctly designed, bushings are a very good choice and very appropriate for the design.

I don't think my problem is the shock pin bottoming out before it gets tight enough... I tightened it a bit without the shock in and the plates were flexing a good couple mm together and there was no sign of pin bottom out yet.

Proper bushings might be acceptable. Mine are not proper bushings. I can't even rotate the reducer in the DU bushing if I grab it with a pair of vice grips. WTF is going on with this thing? Perhaps it's seized up with rust or something? How would I go about trying to pop it loose while I wait for this needle bearing kit?

 

[SirChomps-a-Lot]

update:

I've taken the shock out, clamped the reducer in a vice and rotated the shock. The bottom reducer is fine, moves like it's supposed to.

The top reducer is tight as crap. I have to clamp it in something knurled with a ton of force before I can rotate the shock on the reducer without the reducer slipping in the clamp. It's just way, way to tight.

possible solutions:
1) work it back and forth hundreds of times while watching tv to try and get it to loosen up.

2) flip the shock so the reducer that moves ok is in the upper position and wait for a needle bearing kit.

any more ideas? Possibly lube the top one with something? I know they're supposed to run dry, but they're also supposed to move.

 

[Dogboy]

You could press the reducer out of the top bushing (a couple of sockets, a bolt and some washers will work) and polish the reducer.

 

[SirChomps-a-Lot]

You could press the reducer out of the top bushing (a couple of sockets, a bolt and some washers will work) and polish the reducer.

polish like how? fine sandpaper or something?

mmm, this could work:

 

[miuan]

a cheap solution is to see your LBS and get some half-worn DU bushes for free that they replaced on customers' shocks whose reducer pins were thinner than yours and so the assembly already had some minor play. Yours won't, apparently. It may take some digging in the bin, but why not. Otherwise, ask any of your friends to swap their half-worn bush with yours. Both of you will end up happier.

 

[motomike]

For what its worth, Cane Creek just started using a new setup for their Double Barrels called Norglide I believe. I just got it, super trick and smooth as butter

 

[johnbryanpeters]

I have never had a set of bushings that works worth a tinker's damn. They are either tight enough to seize or loose enough to rattle, no middle ground. I take them apart occasionally and lubricate them, but I'm pretty convinced that they just don't work.

Needle bearings? I would expect them to brinell rapidly.

 

[SirChomps-a-Lot]

SUCCESS! I ghetto polished the reducer with some polishing compound, a paper tower, a bolt, a nut, and a cordless drill.

Put it back in and it's perfect. The suspension is actually noticeably more active.

The moral of this story, children, is don't ignore creaks. If something is creaking, something is wrong.

 

[miuan]

I have never had a set of bushings that works worth a tinker's damn. They are either tight enough to seize or loose enough to rattle, no middle ground. I take them apart occasionally and lubricate them, but I'm pretty convinced that they just don't work.

Just got my shock back from TF Tuned, they changed the bushes and supplied free 3-pc reducers for me as part of the service. Guess what? I could install them in the eyelet and even turn them in the bushing with my bare hand with little effort. And no, they are not loose enough to rattle. I expect them to start rattling faster that tight-fit ones though.