jaxgtr

I have a 2021 Trek Domane and seem to be having issues with the Praxis BB eating drive side bearings. I got caught in the some heavy rain a couple of weeks ago, and the crank just did not feel super smooth on the next ride. I pulled the crank and found the drive side bearing had crapped all the grease out and I replaced the bearings on both sides and everything was smooth as silk. The next ride post bearing replacement was in perfect weather and I did 66 miles, but I kept hearing a slight squeaking from the drive side, and started wondering if I had put any grease on the the drive side bearing dust cover causing the squeaking. I pulled the crank tonight and yep, it was fairly dry, so I went ahead and rechecked the bearing and damn, it feels like it is has sand in it. Non drive side is buttery smooth. I've had many bikes in my day, never had issues with BB bearings, with the exception of the BB 30A on a Synapse, but that is a whole other story.

Anyone had any issues with the Praxis T47 bearings? I got to admit, I am less than pleased that I have had this Domane for less than a year, and I've will have had to replace the bearings twice, but now I am thinking of just replacing the Praxis with a BBInfinite T47.

biker128pedal

Nope. Have an SL6. I have ridden in the rain. After getting home when I went to hand the bike upside down water drained our of the frame. I put the bike back down on its wheel. A little more water came out. Then found a tiny drain hole on the bottom of the bottom bracket. But there appears to be a plastic film inside blocking the hole. Poked at it and water came out. So may have started with the water. For the new bearings did you grease the threads? May be that.

jaxgtr

yea I will have to check that but I did not have any water being retained, as when I replaced the bearings, I pulled the shell as well and regreased it.

smashndash

I went through 2 praxis BBs (one for M30, one for shimano) that got rough EXACTLY like yours. I don't know if it's their sealing system or if their bearings are just garbage. All I know is that I went with a hambini BB and since then everything has been fantastic.

SRAM: https://www.hambini.com/product/hamb...cket-sram-dub/

Shimano: https://www.hambini.com/product/t47-...ottom-bracket/

Unfortunately these are the "racing" versions which means you'll have to be a bit careful about contamination, ironically. But I had the racing version for years and it was butter smooth with 0 maintenance until I pressure washed it after a sandy ride. The bearings ended up rusting. Just occasionally pop the seals, degrease, rinse, and grease. Like maybe once a year lol.

actually if you email hambini, I'm sure he'd gladly swap out the bearings for the contact -sealed ones. Those will give you much more peace of mind

jaxgtr

cool, I appreciate the info. Yea I am more than like going to replace the BB completely and dump the Praxis, I have zero confidence in it. I had not thought about the Hambini BB's , but will look into that.

biker128pedal

Thinking more about your issue I wonder if the threads and face in the frame are aligned correctly. May be the frame.

jaxgtr

yep, thought about that as well.

Dirty Dude

How freely does (or did) the assembly spin with a new BB? Were there any manufacturer marks on the bearings that Praxis uses? If they're good bearings and you're getting early failures, I'd be wondering about the frame alignment too.

jaxgtr

I do not remember any markings on the old bearings or the bb itself, but to be honest, I also did not specifically look for marking, but nothing major jumped out at me. I will be looking at that in more detail, as I am going to pop the drive side bearing out this week to get a better look it. Everything seem to spin pretty smoothly, did not seem to indicate any issues.

Dirty Dude

I looked more closely and Praxis says they are Enduro bearings, which I'd never heard of. Enduro, incidentally, makes their own T47-to-HT2 BB in several flavors.

cxwrench

Enduro is probably the largest bearing supplier to the cycling industry. They supplied all of the BB90/95 bearings for Trek.

jaxgtr

So I went ahead an pulled the bearings and BB, no marring or anything to indicate that a possible frame issue on the bearing, BB cups, or BB Shell. I did notice the bearing cover seemed like it was loose though and since the dust covers basically just sit on the outside and don't seat inside the bearing center like some do, they seem sort of useless. It's been very dry here lately and lots of sand and dirt on the road, so I could see some getting inside the bearing and stuck to the grease, so that could be the culprit here. On my way to pick up my dog from the vet, I stopped by my LBS to chat with one of the mechanics that I trust. After talking with him and some of his like experiences with Praxis, I went ahead and ordered a BBInfinite BB to replace the Praxis.

And because my wife and I have no plans to leave any money to our kids when we die; we paid for their college and they are debt free from that, your welcome; I decided to order some of their pulley wheels too as a why the hell not, type of transaction

The Enduro bearings for the T47 are the same bearings that the BB90 uses FYI,

Koyote

OT: I am of the same mind. My kid got a very privileged upbringing and a first-class education, and so I will not further compound our society’s income inequality; I’ve asked my wife to not pass on any of our wealth to her. (I reckon it’ll be my wife’s decision, given that she is much younger than I am.)

Mojo31

Best estate plan is to spend your last dollar on your last day.

In other words, buy more bikes and cars and boats and stuff.

Koyote

Getting the timing right could be tricky.

Rdmonster69

This thread is relevant to me because I have a 2021 Domane and my estate planning is similar. The bike has been great. I do hear a clunk from the BB every once in a while but otherwise its smooth as silk.

And more bikes this winter and more motorcycles .....definitely more motorcycles....fast Italian ones.

jaxgtr

Yea, outside of the BB issue as of late, the bike has been stellar and glad I went with it. Assuming a Ducati or a Moto Guzzi is in your future?

Rdmonster69

Well .....I have a couple of Ducatis already but another would be welcome .... really would like an Aprilia 550 SXV .... they are insane but tempting. Essentially a factory race supermoto. I'm definitely a 2 wheel junkie.

smashndash

I think tge BBInfinite will be a lot better. Please post back after a couple thousand miles and let us know if the bearings still spin

mstateglfr 

Interesting to hear the Praxis bottom brackets arent working as expected.
My sample size isnt big, but I have 3 Praxis BSA bottom brackets currently and all spin smoothly.

One is 4 years old, is on my main road bike, and has been ridden in rain and/or wet ground countless times. Im guessing it has 5000mi on it.
One is 2 years old, is on my gravel bike, and has been exposed to dust/grit as well as mud countless times. It has 3000mi on it.
The last is 5 years old, has been on 3 different frames, and is currently on my commuter/load bike. Its been pulled half a dozen times and has always looked perfect. It has about 4000mi on it too.

They all run smoothly, the grease is clean each time I look, and the grease stays in place. I admittedly dont actively seek out riding in the rain, but I also rarely do deep cleans and remove the crud that gets caught around bottom brackets.

jaxgtr

I am not indicting Praxis as a whole, but in my specific case, there is something going on, but one does have to realize that not each product by a brand is foolproof, cough *** 1st gen SRAM hydraulic brakes *** cough....

jaxgtr

So got the BBInfinite BB and pulley's yesterday, installed today. Such a difference in how smooth the bearing felt compared to the Enduro bearings in the Praxis BB. Weather was horrible today, so was not able to get out for a ride, but plan to go out for 50 to 60 tomorrow. Super simple install as well.

Dancing Skeleton

Wheels MFG on my 2021 Domane SLR (I bought the frame & built it up).
The only minor issue is that there isn't a lot to bite on when installing the BB.
Otherwise it's fine.

jaxgtr

Yep, looked at the Wheels MFG, but they were not in stock, so went with the BBInfinite. Went out today and got in 63 and really noticed a different in how easy the crank spun. I found myself in higher gears than I typically ride. I generally live in the 16,17,18 tooth with an occasional swing through 15 land using a 14-28 cog with a 50 tooth front. I like the 14-28 since I have no hills and I like having one tooth adjustments when the wind kicks up. I found my self in the 14-17 range a lot today, even though the wind out of the N and NE was pretty strong and in some spots, I did not have anywhere else to go, since my 14 tooth was all I had. Might need to switch back to a 11-28 or a 11-25 since I like a 16 tooth cog.

Since this just the first ride, I will have to get some more time in to see if this was just an anomaly, or do I order a new cassette an 11-25.

Rusty Peters

I have had an issue with the Praxis BB but not with the bearings. My Domane SL5 has a dreaded bottom bracket click that can be eliminated by cleaning and regreasing the bb spindle. The bearings are still very smooth but they are marking up the bb spindle pretty badly. Something is moving, causing the creak. Bike has ~8000 miles on it and bb issues have been present from 1000 miles. A Chris King BB keeps things quiet but seems to bind in one spot and has worn out the bearing sleeves. Before I put new sleeves into the Chris King, I would like to get to the rood cause of the issue.

Facing and bb shell threading were questioned above. What should I look for if that is a problem? Would my local Trek store be able to diagnose an alignment problem?