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Discussion Starter · #1 ·
I had a wheel set made up last year for my xc bike, they use DT swiss 240 front and rear hubs which are quite awesome but I have run into an issue and I am wondering why

They are boost hubs and I ride pretty tame XC trails so not much forces going through them. The front bearings spin really smooth still and when I spin the wheel by hand it spins forever. When I try to spin the rear wheel bearings with wheel off the bike its very notchy and actually has quite a bit of resistance, i estimate about 2-3 watts of resistance but I really don't know. When spinning the rear wheel on the bike it only spins for 15-20% of the time the front wheel would spin and thats without the chain on the bike so the ratchets are not causing any drag.

I managed to fix this by taking the cassette off and hitting the axle with a soft blow mallet to move the bearing just slightly and the axle was spinning really smooth after that with no play in the axle so all was good, but after a ride the bearings must have moved itself back in and the bearings were very rough again...

These bearings should be in good shape, they probably have around 1200km of XC riding on a spark rc 900 dual suspension

Maybe the internal of my 240 hub was machined every so slightly too deep causing load/drag on the bearings when fully seated so I just put a 0.2mm washer that is a hair smaller diameter then the bearing and after fully seating the bearing it spins really smooth and there is no play so I am hoping this fixes my issue, wont find out for sure until I get a few rides in but the rear wheel spins almost as good as the front now, instead of spinning for 20 seconds it will spin for a minute and a half.

Anybody else experiences something like this with their dt swiss hubs?
 

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I've been told this before, that spinning the wheels with no load doesn't equate to how they spin loaded up.
Sure if there's noticeable drag from a brake, but I'm not sure how you can test this. I have a bike with cup and cone hubs that rolls considerably further than any of my other bikes with the same tires.
 

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Drinkin' the 29er KoolAid
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Given you noticed a notchy feeling, I'd still tend to suspect that you've got one or more bearings with some damage. DT uses stainless steel bearings in the 240 hubs, which while good from a corrosion protection point of view are more prone to impact damage due to the relative softness of stainless steel. Likely the races have some dents in them that a little bit of side load emphasized... when you hit the axle you displaced the inner race of the bearing(s) slightly to the center or to the other side of the race and that's why it felt better for a while. Putting a washer under the bearing is probably doing the same thing.
 

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Discussion Starter · #4 ·
Given you noticed a notchy feeling, I'd still tend to suspect that you've got one or more bearings with some damage. DT uses stainless steel bearings in the 240 hubs, which while good from a corrosion protection point of view are more prone to impact damage due to the relative softness of stainless steel. Likely the races have some dents in them that a little bit of side load emphasized... when you hit the axle you displaced the inner race of the bearing(s) slightly to the center or to the other side of the race and that's why it felt better for a while. Putting a washer under the bearing is probably doing the same thing.
Thanks for the info I do suspect the same as you, I am just finding it hard to think that the bearings are already damaged from the kind of riding I am doing using cx ray spokes and lightweight rim. I have read many people praise the original bearings in the 240 hubs and for mine to go after such a short time with easy riding is kind of depressing maybe I just got unlucky.

I will continue to ride the wheel once the weather gets a little more dry and I will report back with my findings. If I need to replace my bearings that's not the end of the world I just don't want to have to buy the DT swiss tool to remove the ratchet ring to make bearings removal easier maybe I will just try to swap the bearings without removing the ring but I hear its a lot harder when doing that

I did have a couple very minor crashes over the last couple years, maybe the bearings took damage when I crashed but I am talking very minor crashes basically like a slow tip over but possibly enough to cause the damage
 

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Drinkin' the 29er KoolAid
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Having replaced bearings in countless wheels over the years, I can say this just seems to be how they fail. Either they will last a very long time, or go bad with low mileage and I've never been able to say that it was due to a crash or anything specific.

I remember having a Hope front hub, which also uses stainless steel bearings, get rough after less than 300kms of riding. I replaced the bearings (with non-stainless steel ones) and now that same hub has over 10,000km of riding and is still smooth. The rear Hope hub on that same bike got to 6000kms before needing a couple of bearings replaced.
 

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Discussion Starter · #6 ·
Having replaced bearings in countless wheels over the years, I can say this just seems to be how they fail. Either they will last a very long time, or go bad with low mileage and I've never been able to say that it was due to a crash or anything specific.

I remember having a Hope front hub, which also uses stainless steel bearings, get rough after less than 300kms of riding. I replaced the bearings (with non-stainless steel ones) and now that same hub has over 10,000km of riding and is still smooth. The rear Hope hub on that same bike got to 6000kms before needing a couple of bearings replaced.
I wonder what the advantage of Stainless bearings are... they should just be using regular steel bearings from factory!

I think I will try these bearings once I replace them, do you think these are regular steel or SST?

https://www.spokeservice.ca/shop/bearings/enduro-bicycle-bearings
 

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Drinkin' the 29er KoolAid
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I wonder what the advantage of Stainless bearings are... they should just be using regular steel bearings from factory!

I think I will try these bearings once I replace them, do you think these are regular steel or SST?

https://www.spokeservice.ca/shop/bearings/enduro-bicycle-bearings
Stainless steel bearings are used where there is a risk of corrosion. Regular chrome steel bearings will rust in the presence of moisture. So if you regularly ride in wet conditions then stainless steel bearings might be a better choice, even if they are slightly less tolerant of impacts. Enduro sells both types.

Honestly I've stopped buying expensive bearings (such as Enduro) for my wheels and now just use cheap ones from eBay. Do my cheap bearings needs more replacement due to questionable quality? Maybe, but its difficult to quantify... I've had Enduro bearings fail just as early as the cheap ones. Most bearings are made in China these days, so quality control is always a concern that even Enduro branded ones aren't immune from.

The question of who makes the best bearings is a rabbit hole for sure.
 

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Discussion Starter · #8 ·
Very true, I actually got some 6902 ebay bearings laying around so maybe I will try to swap those in they seem like ok quality. I just put some 6802 ebay bearings in the pivot for my scott spark and they seem really good there is no play in them, i guess ill find out how long until they start to develop play.

I actually never ride in the wet and gently clean my bike, also the end caps on the dt swiss hubs do an amazing job of keeping water out so SST isn't really needed in my case
 

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Ride More - Suffer Less
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I have a 240S rear as well, about 2 years old. It sounds like I abuse mine a bit more.

I recently noticed the same thing. Was disappointed they didn't go longer.

I pulled the hub apart and cleaned and re-greased the bearings. They feel much better. I should have replaced bearings but didn't want to wait. It is pretty easy hub to service if you have the tools, other than removal of the ring nut.

My xd driver bearings were actually in much worse shape and super notch-y, service long overdue.
 

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Discussion Starter · #10 ·
Its true these hubs are extremely easy to service which I do love, ordered a cheap version of the ring removal tool I am waiting for, seems easy enough to use if you got a vise.

After 5 rides my rear hub is still spinning smooth, looks like spacing the one bearing slightly has helped with my problem most likely because the hub bearing spacing was a little off or maybe I got some slightly off bearings, my freehub bearings feel brand new still
 

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I wanna say that my dt 240 bearings are pretty shitty! after about 600mi they started a high pitch noise and bearing grease was bone dry, I serviced all the bearings and it lasted about another 200mi and start to make noise again, not as bad as before only under load now while climbing, but still either the bearings are low quality of the seals are which is allowing dirty to get inside!

does anybody have a good source for getting some ezo, skf, ntn bearings in the US? should I look at something else? any reason to even consider some ceramic bearings for mtbiking like kogel?
 

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I would never consider a ceramic bearing. Hybrid's, ceramic bearings steel shell will wear quickly due to the ceramic being a harder material. Full ceramic, you're paying out the nose when you shouldn't. Might as well save up for a custom damper(s) instead. Something you can really feel.

IMHO, in the PAC NW better to get some cheap ones, pull both seals & fill them with a great water proof grease (Or high quality grease if you aren't puddle hopping). Sure they aren't stainless, but if external contamination or debris can't get through the extra grease it's not a problem. Additionally, if they have extra grease they won't run dry as quickly.

The sad reality is, most cartridge bearings you buy are NOT for mtb use. They are made for industry & designed & lubed to be used at thousands of RPM with little to no external contamination. The stock grease is very light and fills only a small percentage of the void. Great if you're running constantly at 3-5k RPM in a dry clean environment. Down right disappointing if you're running at 300 RPM getting soaked by muddy water.

If you are lucky enough to have additional seals built into your hubs be sure to clean & grease them regularly. They aren't magic & do require maintenance as well.

The really cheap bearings do have pretty crappy seals. Like, you can see the bearings through the gaps. Not awesome. But honestly for a $1 each not terrible. Especially if your hubs are have additional seals or shield the bearings. If you're feeling crafty you can take the seals off of the older failed higher quality bearing & see if it fits better when you're lubing up the new one. Otherwise, midrange may have more rubber like seals than plastic.

Same goes for frame bearings. If you want to be really disappointed look at the lack of grease in those. Sure they keep your frame nice and clean, no grease spots. But after a season they are best case dry, worst case in self destruction mode.

If you're lucky enough to have additional seals built into your hubs make sure you don't take them for granted. They require cleaning & lube just like any other seal.
 

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No issues on the 4 sets of 240s' that I run. Two sets are 10+ years old while the others are more recent.

Only other thing I could think might be an issue is if the rear axle is being tightened down with excessive force. On DTs' the axle end caps sit on the bearings and when you crank down too tight on the thru axle it can stress the bearings.
 

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Discussion Starter · #14 ·
No issues on the 4 sets of 240s' that I run. Two sets are 10+ years old while the others are more recent.

Only other thing I could think might be an issue is if the rear axle is being tightened down with excessive force. On DTs' the axle end caps sit on the bearings and when you crank down too tight on the thru axle it can stress the bearings.
You seem lucky to me!

I only torque my rear axle to 8 NM but I have the problem, the rear axle puts pressure on the inner races of the bearings so this should not be an issue unless you somehow torque to 30-40 NM.

I think there is a chance DT is tolerancing the bearings too tight on the axle for some 240 hubs because ever since I spaced that one bearing the wheel has been spinning smooth for over 7 rides and these are the original bearings that were feeling very notchy before spacing
 

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I had a wheel set made up last year for my xc bike, they use DT swiss 240 front and rear hubs which are quite awesome but I have run into an issue and I am wondering why

They are boost hubs and I ride pretty tame XC trails so not much forces going through them. The front bearings spin really smooth still and when I spin the wheel by hand it spins forever. When I try to spin the rear wheel bearings with wheel off the bike its very notchy and actually has quite a bit of resistance, i estimate about 2-3 watts of resistance but I really don't know. When spinning the rear wheel on the bike it only spins for 15-20% of the time the front wheel would spin and thats without the chain on the bike so the ratchets are not causing any drag.

I managed to fix this by taking the cassette off and hitting the axle with a soft blow mallet to move the bearing just slightly and the axle was spinning really smooth after that with no play in the axle so all was good, but after a ride the bearings must have moved itself back in and the bearings were very rough again...

These bearings should be in good shape, they probably have around 1200km of XC riding on a spark rc 900 dual suspension

Maybe the internal of my 240 hub was machined every so slightly too deep causing load/drag on the bearings when fully seated so I just put a 0.2mm washer that is a hair smaller diameter then the bearing and after fully seating the bearing it spins really smooth and there is no play so I am hoping this fixes my issue, wont find out for sure until I get a few rides in but the rear wheel spins almost as good as the front now, instead of spinning for 20 seconds it will spin for a minute and a half.

Anybody else experiences something like this with their dt swiss hubs?
Did you place the washer between the bearing and the axle stop or between the bearing and the hub shell? I am on my 2nd 240 hub doing this from brand new. Thanks.
 

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Discussion Starter · #16 ·
Did you place the washer between the bearing and the axle stop or between the bearing and the hub shell? I am on my 2nd 240 hub doing this from brand new. Thanks.
Yes I placed the washer between the bearing and the hub shell, the washers I purchased were stainless steel 28mm O.D, 20mm I.D, and 0.1mm thick. I ended up just using one washer ( I thought I had 0.2mm washers but I was wrong, sorry)

After more tinkering I found out some stuff, if I do not use a washer it will feel notchy with resistance when spinning by hand, with the wheel installed it does not spin too good and for sure has resistance. After installing the shim it does feel smoother by hand but after a few rides I noticed it was notchy again.... but what I learned is it does not matter how it feels when spinning by hand, all that matters is how it spins after installed the wheel on the bike and torquing the axle. The wheel spins perfectly free after I torque my axle down

If I use no washer it does not spin good installed on frame, if I use two washers it spaces the bearing out too far and it spins just as bad as using no washers if not worse. Using just one washer was the sweet spot for me, installed on bike it spins exactly as it should! and its still good one year later :)
 
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