Front hub bearings are shot, is it worth replacing the rears as well?

[Llewellyn]

I have a set of wheels built with alchemy hubs. The front bearings are shot but the rear seems OK at the moment. Is it worth having the rear bearings replaced at the same time just as a precaution? Both hubs were new and built up at the same time so each one has about 9,000km on it.

[aki]

9000km seems short for a hub to fail. You may just have had a bad luck on the front. Why don't you just wait and see the rear also fails?

[Peter P.]

If it ain't broke, don't fix it.

[oldpotatoe]

I have a set of wheels built with alchemy hubs. The front bearings are shot but the rear seems OK at the moment. Is it worth having the rear bearings replaced at the same time just as a precaution? Both hubs were new and built up at the same time so each one has about 9,000km on it.

Replace front, lotsa grease inside bearings, have a set for rear, replace when they are toasted.

[El Chaba]

I would also ensure that the bearings are of a high quality. My own quality control procedure is to insist on SKF brand, but other folks report good experiences with Phil Wood or the ones that Wheels supplies.

[.RJ]

9000km seems short for a hub to fail. You may just have had a bad luck on the front. Why don't you just wait and see the rear also fails?

The bearings on my WI & I9 hubs dont make it that far.

Have had no such problem with shimano, hope or DT.

[NHAero]

I just bought a nice set of used WI T11s on eBay. Front bearings not good, rear seemed OK. For another $30, I thought I'd change them all out and start fresh. My understanding, which may be wrong, is that WI uses shielded rather than sealed cartridge bearings, and so in wet conditions they are more vulnerable. I don't think some additional seal drag is going to ruin my day, so I bought sealed bearings as replacements. I think it will be easier to do the bearing replacement before the hubs are built into wheels (Old Potatoe waiting patiently) so opted to get it done now.

[ergott]

I would replace any worn bearings with Phil Wood or other well sealed bearing. Whenever I have a customer with a hub that had premature bearing wear I would replace with Phil Wood and I don't hear back after that. It's rare that the bearing bores aren't concentric with each other, but another problem can be poor adjustment (if there's adjustability).


Sent from my iPad using Tapatalk

[BdaGhisallo]

I just bought a nice set of used WI T11s on eBay. Front bearings not good, rear seemed OK. For another $30, I thought I'd change them all out and start fresh. My understanding, which may be wrong, is that WI uses shielded rather than sealed cartridge bearings, and so in wet conditions they are more vulnerable. I don't think some additional seal drag is going to ruin my day, so I bought sealed bearings as replacements. I think it will be easier to do the bearing replacement before the hubs are built into wheels (Old Potatoe waiting patiently) so opted to get it done now.


Can anyone shed some light on this bearing question? I have Enve 3.4's with both T11 hubs and DT 240s hubs and the T11's roll noticeably faster. I thought it was down to different drag levels due to the pawls vs ratchet setups in the rear hubs but if the bearings are shielded vs sealed, that could be it.

Any insights?

[ergott]

WI use bearings with standard shield, but there have been some QC issues with bearings in the past. It has gotten better recently.

[NHAero]

When you say roll faster, do you mean in the bike stand, giving the wheel a spin and seeing how long it takes to coast down, or are you saying that it's noticeable when coasting?

Can anyone shed some light on this bearing question? I have Enve 3.4's with both T11 hubs and DT 240s hubs and the T11's roll noticeably faster. I thought it was down to different drag levels due to the pawls vs ratchet setups in the rear hubs but if the bearings are shielded vs sealed, that could be it.

Any insights?

[BdaGhisallo]

When you say roll faster, do you mean in the bike stand, giving the wheel a spin and seeing how long it takes to coast down, or are you saying that it's noticeable when coasting?

Both. The rear rolls noticeably longer in the stand and whenever I have the T11's on the bike I always hit my fastest speeds down a particular descent which I pedal on and then coast at the same point each time. Not very scientific testing protocols I know, but the T11's do 'feel' faster.

[NHAero]

In the stand, that difference could include the effect of shielded vs. sealed bearings. On the road, it's harder to say. For a bike that will see any wet weather, it's seals, because once the lubricant is washed out, the drag will be higher!
My Big Dummy has a Phil Wood rear hub and that still feels good after 7-8 years.

Both. The rear rolls noticeably longer in the stand and whenever I have the T11's on the bike I always hit my fastest speeds down a particular descent which I pedal on and then coast at the same point each time. Not very scientific testing protocols I know, but the T11's do 'feel' faster.

[Mark McM]

Both. The rear rolls noticeably longer in the stand and whenever I have the T11's on the bike I always hit my fastest speeds down a particular descent which I pedal on and then coast at the same point each time. Not very scientific testing protocols I know, but the T11's do 'feel' faster.

Hmmm...

Total wheel bearing drag is just a small number of Watts (see this Velonews Technical FAQ (http://www.velonews.com/2014/03/bikes-and-tech/technical-faq/technical-faq-much-drag-can-eliminate-dropping-two-bearings_321169)). If the difference in drag between the two wheels sets is 3 Watts, and if the downhill coasting is at around 35 mph (about 700 Watts), the drag difference between wheelsets would result in a speed difference of less than 0.1 mph.

[dgauthier]

(...) the drag difference between wheelsets would result in a speed difference of less than 0.1 mph.

528 feet in a one hour race?

[Mark McM]

528 feet in a one hour race?

There is no doubt that in some events every little bit helps, and there can be a little bit of performance gain in hub bearings. My point was a gain this small would be very difficult to discern in an uncontrolled coast-down test - other variables could be (and probably are) larger.

[BdaGhisallo]

Hmmm...

Total wheel bearing drag is just a small number of Watts (see this Velonews Technical FAQ (http://www.velonews.com/2014/03/bikes-and-tech/technical-faq/technical-faq-much-drag-can-eliminate-dropping-two-bearings_321169)). If the difference in drag between the two wheels sets is 3 Watts, and if the downhill coasting is at around 35 mph (about 700 Watts), the drag difference between wheelsets would result in a speed difference of less than 0.1 mph.

Having been around a while and having read numerous articles on the subject over the years, my head knows that there shouldn't be much of a difference. But, damn, the WI T11's definitely feel like they roll much... much better.

[NHAero]

Mark's example was a 3W difference, and I'm guessing that is quite a bit higher than the actual drag difference between high end hubs. For us mere mortals, without dedicated race mechanics prepping our rides before each race, I think having seals on one's bearings makes sense.

There is no doubt that in some events every little bit helps, and there can be a little bit of performance gain in hub bearings. My point was a gain this small would be very difficult to discern in an uncontrolled coast-down test - other variables could be (and probably are) larger.

[BdaGhisallo]

Mark's example was a 3W difference, and I'm guessing that is quite a bit higher than the actual drag difference between high end hubs. For us mere mortals, without dedicated race mechanics prepping our rides before each race, I think having seals on one's bearings makes sense.

I wonder what the difference in drag is between the 3 pawl system of the T11's and the ratchet rings of the 240s? That could explain some of the difference I am feeling.

[Mark McM]

I wonder what the difference in drag is between the 3 pawl system of the T11's and the ratchet rings of the 240s? That could explain some of the difference I am feeling.

At descending speeds, the bearings and pawls are only a very small fraction of the total drag, and are unlikely to cause a perceptible difference in speed. The total bearing/pawl drag can be smaller than the difference in rolling resistance between two tires (even of the same model).

If the pawls are creating a perception of different drag, it is most likely due to difference in sound levels, which the brain might mis-interpret as differences in speed/drag.

[NHAero]

FWIW - I changed out the bearings in my WI T11 front hub last evening, and it took about 20 minutes - someone who does this often and has dedicated tools can likely do it in under 10 minutes. Since I was tossing the old bearings I just knocked them out. The new bearings went in by setting the bearing on a block of wood, then setting the hub shell carefully straight above the bearing, and tapping it gently to get the bearing started into the hub shell straight. Then I flipped it over and used a socket that just pressed on the outer race, and tapped the bearing in with a rubber mallet. Quite a difference in feel when it was all done. Hoping to get to the rear hub this weekend, a bit more complicated but it looks do-able for the home mechanic. WI has excellent instructions, step by step with photos.

[BdaGhisallo]

FWIW - I changed out the bearings in my WI T11 front hub last evening, and it took about 20 minutes - someone who does this often and has dedicated tools can likely do it in under 10 minutes. Since I was tossing the old bearings I just knocked them out. The new bearings went in by setting the bearing on a block of wood, then setting the hub shell carefully straight above the bearing, and tapping it gently to get the bearing started into the hub shell straight. Then I flipped it over and used a socket that just pressed on the outer race, and tapped the bearing in with a rubber mallet. Quite a difference in feel when it was all done. Hoping to get to the rear hub this weekend, a bit more complicated but it looks do-able for the home mechanic. WI has excellent instructions, step by step with photos.

What brand and type of bearings did you install?

[NHAero]

I bought Enduro ABEC-3 from BikeHubStore, and they came in 2 days. Fully sealed and very smooth, especially compared to the Enduro ABEC-5 bearing that were in there. I actually spoke with WI tech folks and their opinion about ABEC-3 vs ABEC-5 was less drag from the seals on ABEC-5. Not sure if that is because they are spec'ing a bearing with less rigorous seals to get less drag, but for this 63 yr old cyclist, I decided to go with best seals if that is really the difference.

If it was middle of winter I might have hunted around more for bearings, but BikeHubStore stocked all the sizes I needed, and I didn't find a quick source for all sizes in Phil Wood (which are Japanese NTN bearings, FWIW).

What brand and type of bearings did you install?