Everything about building wheels, glueing tubs, etc.
Geoff
Posts: 5093
Joined: Sat Dec 13, 2003 2:25 am
I've personally never bothered, although I have thought about it. I have never seen or heard of a study on that, maybe the forces generated by the speeds we ride don't create enough of a problem. Still, I do always put the magnet directly oppsite the heaviest part of the rim...

sungod
Posts: 1463
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk
did some quick calculating...

if you're doing 60kph on tyres with circumference 2.132m, a 6g imbalance at 0.3m from axis would give about 3.6 newtons force

the wheel be 'lifting' then 'pushed down' ( and pulled forward/back/etc.) by the equivalent of c. 370g almost 8 times a second

assuming most weight is on the rear, it's the front that will be most affected, but that's still likely to be only 2-3% at most of the total downforce on the front wheel, so it's not going to lift off

it's the extent by which this force causes the tyre/etc. to deform that will determine how much vibration is caused

assuming i didn't mess up the sums, i doubt it's going to get close to the vibration from the road surface

fdegrove
Tubbie Guru
Posts: 5851
Joined: Tue May 03, 2005 2:20 am
Location: Belgium
Hi,

You can most certainly feel the difference in the bike's handling when going fast enough.

Ciao,
Being a snob is an expensive hobby.

sungod
Posts: 1463
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk
agreed, but only if the imbalance is big enough wrt the system weight

out of four sets of wheels, none balanced, but i only notice anything on one set at high speed on very smooth road

fdegrove
Tubbie Guru
Posts: 5851
Joined: Tue May 03, 2005 2:20 am
Location: Belgium
Hi,

agreed, but only if the imbalance is big enough wrt the system weight

If it makes a difference then it matters. It's about time we take the minor imperfections out of our bikes, wouldn't you agree.

We strive for perfection, do we not?

Ciao,
Being a snob is an expensive hobby.

mellowJohnny
Posts: 484
Joined: Thu Aug 16, 2012 12:56 am
Location: YYZ
At speed it is perceptible if I focus on it. If I hold the bike by the stem and give the front wheel a good spin it is definitely noticeable.

I agree it's an imperfection, and I'd definitely like to correct it. If nothing else it's annoying.

Could also be the set of sh*tty tubs currently mounted as I wait for some Vittoria Corsa CX. I'll let you know if it goes away with a set a proper tubs mounted.

sungod
Posts: 1463
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk
tbh i'm in two minds about it, in my r&d days i'd take as long as it needed to tweak things and even choose electronic components on aesthetic grounds, when i moved to the development engineering group, the approach was: it's good enough, ship it - i did some ugly stuff in those days, and now i'm just a whore to commerce

adding balancing weights also offends my inner ww, but if i could get some negative masses, hmm...

eurperg
Posts: 789
Joined: Mon May 14, 2007 10:32 am
Location: Finland
Is Vredestein tubular cement just rebadged Mastik? The can even has the same light purple color...?

fdegrove
Tubbie Guru
Posts: 5851
Joined: Tue May 03, 2005 2:20 am
Location: Belgium
Hi,

Is Vredestein tubular cement just rebadged Mastik? The can even has the same light purple color...?

Given that most Vredestein tubulars are manufactured at the same plant as Vittoria it would not come as a surprise if their cement is similar. I'd doubt it to be the exact same formula though.

When in doubt, use Masitk One. At least that's my motto.

Ciao,
Being a snob is an expensive hobby.

Kjetil
Posts: 1370
Joined: Sat Jul 30, 2011 1:17 pm
Location: Hamar, Norway
Contact:
Post Roubaix, a question: Was Vacansoleil-DCM partly on rebadged Veloflex Arenberg? A bit on the skinny side or?

Also, I mounted 3 Vittora Pavè CG (24mm) over the weekend for a club mate. Very easy to work with, and seemed to fill out the Zipp 303 "pavé", i.e. last gen. before Firecrest pretty well. Much better than the Veloflex Extremes he insisted on (also for gravel roads, pssst! flap flap flap) last year.
Bianchi-Campagnolo

veganeric
Posts: 151
Joined: Sat Dec 11, 2010 2:25 am
Location: MN
Does opened, but unused, Mastic One have a shelf life? If so, what is it? I'm trying to decide if it's worth buying the big can of it. I tried searching the site with google but didn't find the answer.

fdegrove
Tubbie Guru
Posts: 5851
Joined: Tue May 03, 2005 2:20 am
Location: Belgium
Hi,

Generally speaking it's not worth it to buy a can of glue unless you plan on gluing up dozens of tubs.
Once the can is open the solvents start to flash off.
Since you'll likely spill some glue on the can's edges it will then no longer be hermetically sealed allowing more of the solvents to evaporate.
The glue will eventually become thicker and thicker making it harder to spread on the rim bed.

Ciao,
Being a snob is an expensive hobby.

sungod
Posts: 1463
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk
^^^this

the last can i had was ok for about 4-5 months, i took care when refitting the lid, then the last 4-5mm got very thick, as above probably i'd got too much dried glue on the rim by then

but i'd used almost the whole can, so it was worthwhile vs. tubes

veganeric
Posts: 151
Joined: Sat Dec 11, 2010 2:25 am
Location: MN

Have either of you (or anyone else) tried transferring it to a squeeze bottle, as I've seen some mechanics do? I imagine that would eliminate the problem, as the small surface area of the tip could easily be cleaned off with solvant before recapping. This would have the added benefit of making application easier.

astranoc
Posts: 458
Joined: Sat Jun 26, 2010 11:43 am
I know you 've said it 100 times.. but one more quick recap for the newbie please..

New rims
->clean with acetone/gently sand
->apply thin layer on the whole rim on the center and sideways and leave it to dry for a few hours
->apply a second thin layer on the rim and leave dry again
->apply a layer on the basetape and mount it on the wheel while centering it fast
->pump tires to 130 psi and leave to cure for at least 24h

Correct?

Now about the spare tyre, how long do you leave the glue dry before you fold it? And do you fold it glue to glue?

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