Things to know

On 12/8/2020 12:39 PM, Mark Cleary wrote:
On Tuesday, December 8, 2020 at 7:58:13 AM UTC-6, AMuzi wrote:
On 12/7/2020 10:00 PM, wrote:
On Monday, December 7, 2020 at 12:49:52 PM UTC-6, jbeattie wrote:
On Monday, December 7, 2020 at 10:08:40 AM UTC-8, wrote:
On Monday, December 7, 2020 at 11:21:40 AM UTC-6, wrote:
Op maandag 7 december 2020 om 18:16:25 UTC+1 schreef :
On Sunday, December 6, 2020 at 3:26:11 PM UTC-8, Mark J. wrote:
On 12/6/2020 2:17 PM, Mark Cleary wrote:
So if you take a front road wheel and spin it by hand how long does yours spin before stopping? Today I check my front Ultegra bearings and they were fine the 10000 plus miles shows zero wear. I did pull the bearings and re-greased, cleaned them up but of course when you dump the while lithium grease back they look dirty again. Maybe should have used my marine grease but did not.

In any case I spun the wheel afterward by hand the computer has it getting to 9mph and it spins about 45 seconds. I then went over to the other bike that has pretty much a front wheel with 105 hubs and simply spun that one. It manages to spin for a minute. Both smooth but I wonder if that means a damn thing?
Deacon Mark

I doubt the 15sec difference means much. Could be a difference in seal
friction (if either of your hubs has the rubber cone-to-dust cover seals
that used to be popular). Could be a minor difference in how tight you
adjusted the cones. Both sound fine to me. Besides, I doubt we're very
consistent with how hard we spin a wheel.

What might be a finer measure of hub friction: Spin the wheel very
slowly so that the wheel quits "turning over" and starts
spinning/swinging back and forth as the heaviest point (usually either
valve, reflector, or rim join, but not always) seeks bottom. Usually
the wheel stops when the heaviest point is *near* bottom but not *at*
bottom - the heavy point swings past bottom then stops, b/c friction
overcomes the tiny bit that the weight is off-bottom.

Spin a few times and compare the distance of the shortest "swing," and
how close to bottom the heavy point is. Less friction will make the
wheel continue to oscillate with shorter swings. Higher friction will
stop the wheel when the swings are still kinda large. Of course a
better-balanced wheel will confound all this.

PS - just so long as you get *some* oscillation before the wheel stops,
you're probably doing just fine.
With reasonably good components the total loss to rolling resistance in the bottom bracket, wheels and tires is about 15-20 watts. While this might make a difference to a pro in a TT, you or I are very unlikely to even notice that. We generate perhaps 300-400 watts full time power. The human body isn't built to notice 10% losses unless you have been riding well above your FTP for some time and have been forced to slow up. Then while you can tell that you're going slower you simply couldn't tell the source of the drag - whether bicycle or body exhaustion.
Make that around 150-200 W full time power. 300-400 W full time power is Pro level, and even they can't sustain that for 5-6 hours. Really you do notice 15-20 Watt loss.

Lou
I notice the greaser Shimano uses seems to be lighter than the stuff I had. It was almost clear and looked clean for sure. Then wiping the grease off and cleaning the races and ball bearings everything looks nice and shiny. Repacking the bearings then it looks like a bunch of balls in mash potatoes. I notice when spinning the wheel by hand is simply comes to a rest and does not oscillate and start going the other direction. I do have the computer magnet still on spoke so not weighted even. To set the pre load not much as you just push the cone back on and the cone holding tube. Then tighten at end with 5mm allen wrench but it is a set amount already in advance.
Deacon mark
Maybe you need Dura Ace grease. https://tinyurl.com/y5udu5jz 105 grease is much slower. Sora grease is made out of tubular cement and should be avoided.

Fun diversion. Back in the '70s, I was riding in this shop ride crypto-race, and one of the guys (who was struggling) looked over at me and said "I think I got Tubasti in my hubs." Make sure you do not have Tubasti in your hubs -- even if you put it in six zip-lock bags and lock it in a vault, it will find its way out. https://www.youtube.com/watch?v=TdUs...RetroAlexander

-- Jay Beattie.

Would it be better to have Vittoria Mastik or Continental rim cement instead of Tubasti? I did a Google search on tubular glue and was shocked (SHOCKED!!!!) to see so many companies making tubular glue. Vittoria, Continental, Tubasti(Velox), Vredestein, Specialized, Hutchinson, Panaracer, Schwalbe, Zefal, Challenge(Clement). Who would have thought there needs to be that many companies making tubular glue. I can count on one hand the total number of people I've met in my bicycle riding life who use tubulars.

Al the current products are OK (no more Bikit and other
dreck). People like what they like but there are not
dysfunctional tubular cements now.


So after my ride today a 55 miler I check the wheel and it spins again about 35-45 seconds from a hand push at 9 mph showing. I decided to pull the axel and just check things out. Nothing wrong but this time I was a bit more careful with the preload. I snugged the cone up checking the play all the way. Then when I get to where there is no play but still just easy finger tight, I could still give it some a tad more tightening. I decide that is what I must have been doing so I made the adjustment again and this time when I got the to no play in the hub but finger tight-easy, I stopped.

I then put the hub all back together and still no play spins nice. I mounted the tire on the bike and gave it a spin. This time at 8-9 mph the wheel spins almost 2 minutes to stopping. So this this sound better or did I really not do anything really that much. It is interesting in the the hub still gets the pressure from the skewer being clapped tight, but spins at least twice as far. I wonder if they would let me be a mechanic somewhere in crazy land.
Deacon Mark


As discussed here recently, a properly adjusted bearing has
just contact of all the balls. When loose, load is only on
one point which of course accelerates wear. When adjusted
too tightly the mechanism introduces another load, evenly
but a load nonetheless, which can be severe for rapid wear.

Note that QR axles will deflect when the skewer cam is
locked, making the cones a bit closer to each other, i.e.,
tighter. So ideally one would check the adjustment in a bike
with closed skewer rather than in midair.

It's always a good day to lubricate your skewer cam BTW.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971