DT Swiss star ratchet issues

How old are yours?

Can you post a picture of the ratchets? It's obvious when they are worn as the edges of the teeth get destroyed. Which version (18, 36, 54t) are you using?

If you have to replace the ratchets you'll get a tune if the grease with them.

You might be a candidate for the new ratchet version https://www.dtswiss.com/en/wheels/wheels-technology/ratchet-deg-technology

Fellow large person. I find that star ratchets last years for me, as long as I maintain them and use the recommended grease. Once they've slipped, the damage is done and you need new ones. A strip and re-grease does buy you some time though. Another bit of learning, don't go fir the high "tooth count" ones. Go basic. They last longer for big fellas.

Have I killed the star ratchets?

Probably, nothing likes slipping under load. Especially not repeatedly

Are these really sensitive to the type of grease you use (I’ve not got any of the recommended DT Swiss freehub grease)?

Not sure if the design has changed at all. But they used to be. I've got a pot of the DT Swiss stuff that i bought ~10 years ago, so haven't tried with the wrong stuff lately!

Do I need to find something stronger/stiffer to take my weight better?

Stick a new set in, with the correct grease and see how it goes.

What tooth count do you have?
The cheaper hubs tend to come with 18T ratchets but they are stronger than the 36T ones the posh ones use. It does sound d like you’ve stripped them. No idea what’s so special about the grease, but I’ve always used it as it came with the service kit and you don’t use much.

I've got a near 20 year old one, works perfectly but TBH I've never greased it.

Are you sure there's not another problem, that is been masked?

The Deg variants are more about offering a higher POE without compromising durability. Shouldn’t be an issue for you with any version.

DT specifically state that their special grease should be used, but due to being a tight bastard, I’ve used Finish Line Wet Lube on mine for over 20yrs.

Early 240 EXP had faulty ratchets - got FOC replacements for mine.

Is that what you have?

Definitely get the "special" grease and keep on top of the servicing. I pop the freehub off once a year and clean and relube.

Some extra context:

I’ve got the 18T ratchets in a 350 boost hub.

I’d guess the hub has done something like 1000-2000km of riding since the wheel was built. Most of those miles are probably in reasonably gentle conditions as my local trails don’t really have much in the way of mud and are quick to drain when it does rain.

The skipping doesn’t happen in all gears which was the main thing that made me wonder if the ratchet is not entirely at fault. It doesn’t happen at all in the easier gears where logic says I can apply most torque to the freehub and it should be most likely to skip. It’s only when I’m in gears 8-12 where this happens and the higher the gear the more likely it is.

Given the above I was wondering if the freehub may be flexing when I’m in the higher gears, and the force from the chain is acting further away from the bearings, causing the ratchets to bind and not engage properly.

Sounds more like chain/cassette wear as that’s more likely on smaller sprockets with less chain wrap.

sillyoldmanFull Member
The Deg variants are more about offering a higher POE without compromising durability. Shouldn’t be an issue for you with any version.

Fine in theory, but in reality, the 54 tooth version does not suit heavier riders all that well

Not tried that one as I’m not that fussed about POE personally, but likely a fair point!

He’s on 18T anyway, so should be fine for many many years.

I'm a very heavy rider (over 125KG) and run the 54t ratchets for both gravel and MTB with no issues.

But then again, I do keep on top of maintenance and use the correct DT grease.

The higher engagement ratchets are reliable but less tolerant of neglect, give em a clean and a grease a few times a year and they're generally fine.

Same applies to fast engaging pawl hubs TBH.

The 18 tooth versions are basically as bombproof as hubs get.

In that case how old is the chain and cassette? Have you checked the chain wear level? Do you have a spare (new) chain and cassette you could fit to remove them from the equation.

Given the above I was wondering if the freehub may be flexing when I’m in the higher gears, and the force from the chain is acting further away from the bearings, causing the ratchets to bind and not engage properly.

I do have a vague recollection of someone finding a bent axle giving similar symptoms.

The 18T ones are pretty indestructible ime. Most reliable of all the freehub designs by far. I had one that was still going strong after probably 18 years.

Timely thread - I’ve stripped my 370 hub and found the axle had snapped. New axle and bearings are ordered. I’m struggling to find any “DT special grease” in stock anywhere. Any recommendations for an alternative?

Other reasons for thinking this is chain slipping rather than ratchet:

1. You're slipping in higher gears. These put less torque through the ratchet than lower gears. Would expect ratchet slip to happen in lower gears.

2. The distance ridden (1000-2000km) is chain wear distance not ratchet distance (which is much longer).

@richwales given you need parts anyway do the ratchet upgrade, it comes with the grease.

the only time ive had issues with the ratchet slipping is when i used 'normal' grease instead of the DT swiss stuff..

UK Stock of the grease isnt great unfortunatley.. i had to order my last couple of tubes from Germany..

youll end up googling alternatives and discover a few places saying DT Swiss special grease is the same as molykote TP42.. then find it on ebay for sale in small tubs.. (its a sort of beige colour)

i thought id found the cheaper easier version of special grease in TP42.. as it works ok in summer.. but come autumn/winter when the temperature dropped it seemed to thicken up in use in the hub and i experienced one or two slippages.. cleaned up and switched to special grease.. and everythings working as it should again.. and had no issues since..
(had the same issue in a modern 240 exp hub with a 54t ratchet.. and an ancient specialized S-works hub (with DT Swiss internals) with an 18t ratchet.. and a 350 hub with a 36t.. so it was deffo the grease..)

im fairly sure the DT Swiss stuff is based on the molykote TP42.. but it definitley got something else in it that helps in lower temps..

I'm sure you haven't done this..

But I have on occasion seen people put the springs back in the wrong way round, and that seems to cause similar issues.
Also worth checking the springs haven't bent and aren't providing the correct amount of 'push' back.

I've checked the chain and cassette and they look to be in good condition still, this was my first suspicion as to what was going wrong the 1st time it happened.

Will see about getting some pictures of the ratchet parts and ponder how the get the axel out to check that against a straight edge.

Otherwise sounds like having the proper grease is a good idea to remove that from the equation so I'll see if I can track down a tub anywhere.

They can also slip and even stop working altogether if gunked up, I've taken DT wheels apart on the trail and fixed them b wiping down and lightly lubing with chain oil

I’m always confused as to how much grease to put on. It says a very small amount but then the DT Swiss videos show it being lathered on with a brush. Definitely not my definition of a small amount.

IME they're basically immortal. Most of my DT hubs started out as ex1750 wheels so they're knocking on 20 years old. I've got the official DT 36T upgrades in them all but all those parts are at least 10 years old. I'm not heavy, but there's been times when I've been decently strong, and I did used to ride em basically all the time. They've all been properly bombproof reliable.

Tbh I'm not sure any of the rider stuff makes much difference? for wear, it can only really be whether they're locking up properly on drive or not. And that's basically got to be weak or otherwise not working properly springs, something restricting the ratchet's movement (which could include alignment) or something preventing full lockup. Too much dirt, too thick grease, worn out tired springs (not an issue I've ever seen). Just possibly a really heavy rider could flex the axle, especially if it's got an unsupportive maxle in it, but I'd be surprised, they are stronk despite the design being older than 12mm axles.

Re grease, I've never had the proper DT stuff, I use a tiny wee swipe of slick honey on the faces. It's tempting to fill things with sticky waterproof grease but that's the wrong thing here I reckon, that'll keep the sliding parts moving but could prevent proper locking up. I think I'd rather use oil than a thick grease.

The sealing is OK, it's not brilliant, it should keep solids out but can let a little water or thin mud in over time. But inspection and cleaing is really easy, just pull the entire cassette off (the end cap can be very sticky, if the whole cassette won't pull off, get some molegrips on the endcap and rock it off first).

So I've given up trying to find any of the DT Swiss Special Grease in stock and have just ordered a small (cough, 1kg, cough) tub of Molykote TP-42 from eBay to see if that helps get rid of the slipping.

Looking closely at the ratchet rings I can see some polishing on the outer edges of the teeth but in general they look to be in reasonable shape with no bits missing or badly worn. Not that I know what good/bad looks like in this context.

They look absolutely fine.

Assuming the hub's been assembled correctly then if it's still slipping I'd look at the Cassette or other factors.

Look fine to me as well. All the worn ones I've seen have chipping on the outer corners.

Yeah that;s just normal polishing.

If you're still haivng problems I'll have some standard ratchets somewhere,not entirely sure where though 🙂 But I don't think it's your issue.

I have 350 rear hub with a ratchet. I can hear what sounds like a pulsing in the freehub when I coast at higher speeds. Has anyone got any ideas as to why that may be?

Mine all pulse like that. I think it’s centrifugal force, or some rotational force anyway, working against the spring and then the spring pushing back.

There was a quite entertaining big thread on it a few years back where the poster downgraded as their OCD could not cope with that noise.

Like a quieter/louder thing? If so that's pretty much just the noise they make. No idea why though.

There was a quite entertaining big thread on it a few years back where the poster downgraded as their OCD could not cope with that noise.

and I got a nice 54t ratchet and tub of grease out of it

Just had one of mine apart for a fettle/regrease as it was getting slightly noisier. Still some evidence of pink grease knocking about so it’s all pretty well sealed in there. Bearings still super smooth. Cleaned and regreased with Special Grease.  Still does the loud/quiet thing but it’s less noticeable with fresh grease in.

It’s in stock here albeit £13.

https://www.sjscycles.co.uk/lubricants/dt-swiss-molykote-tp-42-special-grease-for-star-ratchets-20-gram-tube/

Doh.

I guess I can console myself knowing that the massive tub only cost me £38/kg rather than the £699.50/kg that the (perfectly sensibly sized) 20g tube works out at.

If anyone needs any let me know; I feel I may have some going spare. 🤦‍♂️

Sounds like an eBay opportunity. Buy 20 empty lip balm tubs, fill them and punt on eBay for a fiver a time.

Had the first ride out tonight after using the TP-42 to grease the freehub. Things started out well with no slipping on the first two descents where it had been a regular problem under hard acceleration. But at the bottom of decent number three it slipped again then went on to do it much more regularly for the rest of the ride.

Going to try one more time with slightly less of the paste in there to see if that might help things. If that doesn’t work it all goes in the bin and I have to buy a new bike.

I’ve checked the chain and cassette and they look to be in good condition still

I'm still thinking its this thats worn

Lets see pics of chain and cassette have you measured the wear on chain?

Or the chain ring. It would be a pain buying a new chain/chainring/cassette to swap out but as a trial but even if they weren't the issue you would say least then have spares for the inevitable replacement.

Have you checked all the teeth. I had a random slippage a year or so back that was caused by damage to a single tooth on the chain ring. Hit it on a tree and had caused a bur on the inner side. This caused the chain to sometimes not sit properly and then slip. 5s with a file sorted it.

+1 for checking your chainrings and cassette. I recently re-jigged a bunch of components from one bike/the cellar to another. First ride out the chain was skipping on every high grunt climb, which could easily be mistaken for freehub slip. Initially I thought, new chain/old cassette, but then realised that it was fine in the outer ring of a double, did the rest of the ride in the big ring and all was fine, apart from my legs.  The inner chainring was goosed. Fitted a new/old ring I'd bought on eBay and all was fine.

If you can, stick the wheel in another, known functioning okay bike, and see if the skipping goes. If it does, it's more than likely your chainring and/or cassette, particularly if you've recently fitted a new chain.

Fwiw, I've never had a star ratchet DT Swiss freehub slip on me over lots of bikes and loads of kms.

Pretty sure I have some near new 18t rings if you want to try some new ones.

Just one to check.... Do you take your rear wheel off to transport the bike? Ive had numerous customers with trashed freehubs/slipping ratchets over the years and the common factor has always been removing wheels regularly for transport. Its possible on DT hubs due to the fact the freehub is very loose and unsecured on the axle to have the freehub slip a bit outwards (or indeed the cassette fall off completely), but when you come to fit the hub there's a step inside the end cap which means that you can tighten the axle up and it won't remove the last couple of mm of play. That leaves your freehub free to move around a bit even though your axle is 'tight' - causing the issues you have.

If this sounds like you then make sure before you fit the wheel each time you ensure the end cap is fully seated. You cant rely on the axle tightening to do it for you.

Chain is somewhere in between 0.25 and 0.5 on the wear gauge.

cassette has a couple of tiny burs on some of the teeth but otherwise looks ok to my eye

edit: image upload from IOS/safari seems to be broken  will try something else

upload to https://postimages.org/   and link on here

I'm going to be the first to say 8-11 look battered, those were also the ones you indicated slipped.

That chain checker design is not the most accurate btw.

For me, the cassette wear looks more  uneven than mine. It is usual to get more wear in 6-11 but that looks quite aggressive to me. 1-7 and 11 + 12 look fairly fresh so I'm guessing most of your miles are in 8-10?? That focused wear is going to shorten the usual lifespan.

I'd be sticking a new drivetrain on. change everything ...Chainring, cassette  and chain

Maybe a good case for a bigger front ring as well to shift the load up the cassette where there is more chain wrap.

Christ almighty. Not surprised that’s slipping.

Do we really think the wear on this is that bad? Looking into the teeth there doesn’t seem to be a great deal of wear even if most of the surface finish has been taken off the sides.

Unfortunately the only spare cassettes I have at the minute are microspline so not going to be cheap to try a fresh one out. Definitely would make sense to go for a larger front ring when I do though as the hills round this way aren’t exactly epic.

@benpinnick may be on to something though as the wheels do get taken off when the bike gets stored. Is this usually permanent damage to the hub/ratchet/freehub or is it just a case of needing to take a bit more care when putting the wheel back into the frame?

If you're out of the saddle could it be frame flex or something?

I can never tell how worn a cassette is by looking tbh.

If it was the freehub at fault, I think it would be more likely in the lower gears as the 50t will put 5x the amount of torque through there as the 10t.

Blimey. I'd be installing a bigger chain ring too. Not much chain engagement in those smaller cogs and three of them look a bit haggard.

Frame flex could be part of it I guess. Not sure I can face swapping the frame out to try and fix it just yet though. 

You either have thighs of Oak, or that's an E-bike. Either way, look at the shadowing on the rear faces of those smaller cog teeth. Where the chain is being pushed hard against them. Looks to me that the teeth are slightly flared, which is a sign that the cassette is borked. If you were able to use the larger cassette cogs (by using a bigger chain ring), the teeth would not wear so quickly, and there would be more engagement between the cogs and chain.

Also, that doesn't look like a 12 speed chain checker. Use something like a Park CC4.

I don't think frame flex is relevant. Just large force being placed on a few cog teeth.

Unless running a 10t oneup shark mini driver, I've never had a dtswiss freehub pull off the axle when off the bike without significant user intent. I guess if you hot swapped cassettes between wheels you could wear out the o-ring and reduce its efficacy but surely not from straight wheel out stuff.

However, the only time I've mashed any star ratchet teeth was due a loose rear axle under a fairly significant amount of torque. Rounded a few teeth and it would give up on enthusiastic pedalling.

Presumanly with a spotter, you could stand on the pedals in those smaller gears and watch if it's the chain jumping or the cassette turning..

The LTJC-001 is compatible with all derailleur chains. For 9 and 10-speed chains, replace chain at or just before the 0.75% readings. For 11 and 12-speed chain, replace at or just before the 0.5% reading. Check with manufacturer for specific replacement instructions.

https://ztto.net/products/ztto-mtb-bicycle-chain-wear-indicator-tool-links-checker-aluminum-alloy-road-bike-repair-accurate-tools

Seems that you want to blame everything else other than what you're being told.

Even if you did have another issue the worn drive chain would make diagnosing harder. It's the most obvious cause and the simplest thing to 'fix'.

IMO you'd need some fairly drastic frame flex to cause skipping and would have other indicators like tyre rub on the stays. You've also clearly had the hub apart numerous times, would you have made the mistake of not fitting the end cap properly every time? Again I think you'd have other signs of this like the hub seeming slightly too wide when you went to put it into the frame. TBH I also am struggling to see how what Ben describes would occur (though he sees way more bikes than most us).

Do we really think the wear on this is that bad? Looking into the teeth there doesn’t seem to be a great deal of wear

Not on the bits that are left, but there’s a whole it of material gone. For me, it’s the shape gaps that’s tell tale. Look at the 24t cog in your first picture. Some of the gaps are symmetrical-ish and some are the shape of breaking waves. There are also some where the gaps are much wider than others. That’s very typical of heavy wear. The areas where the wear doesn’t look so bad are probably around the shift ramps that are profiled to handle the change of cog.

For 9 and 10-speed chains, replace chain at or just before the 0.75% readings. For 11 and 12-speed chain, replace at or just before the 0.5% reading

This is new news, I’ve had the numbers quoted for the 8/9 speed chains in mind and that anything less than 0.5 was fine.

Guess I’ll be off to buy some new bits then.

That cassette is gubbed. Particularly 12/14/16/18T

eBike by any chance?

Not an ebike.

bnail-IMG-2899-c.jpg" alt="" />

So fitted a new SLX cassette and XT chain to replace the GX parts that were in there. Even factoring in the cost of a new (steel) micro spine free-hub it worked out about £55 cheaper than going for the SRAM parts. I also took some of the grease off the face of the star ratchet parts as they had gone very quiet and I suspect there was a bit too much in there.

First ride out and something skipped once, making quite a racket down by the rear hub. So a lot better than things were previously where I’d loose count of how many times it had skipped despite taking it easy most of the time but not perfect. Can’t decide if it’s worth chasing things further or just leaving it there. Will see how it goes after a few more rides I guess

Did you adjust rear mech indexing to take into account the sram > shimano change set up? No mention of changing front ring so is that still the old one and is the chain length correct.

Gear indexing checked/tweaked and seemingly running fine. Shifting is generally sounding and feeling much nicer/smoother with the shimano cassette and chain on there.

Same chainring.

Chain length set up as per SRAM user manual instructions rather than just matching to old chain.

f that doesn’t work it all goes in the bin and I have to buy a new bike.