Glueing tubulars [the tubular thread]

Everything about building wheels, glueing tubs, etc.
sungod
Posts: 1500
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

jlok wrote:
Mon Jan 15, 2018 9:06 am
Hi all I'm tubular newbie. I dive into tubular sea because I'm building a new c-brake bike to join some local racing. And I think why not try to glue mine to understand why you guys are so into it...

anyway, I have already done the 1st base layer on the rim and the lovely Vittoria Corsa, and read through some pages up to ard 60...

one thing I'm not so sure is the actual mounting step below. Would the grabbing of the tire "damage" the dry glue layer on the tire?
https://www.parktool.com/assets/img/rep ... e_2-73.jpg
it shouldn't hurt the glue layer, but it's not necessary to touch the glue layer anyway - and no need for gloves, i don't get glue on my fingers, gloves just affect grip/feel and make it harder

when mounting you should be gripping the sides on the tub as you mount it, maintaining even tension as your hands 'slide' along moving the tub onto the rim

takes practice, but as i do it i can feel the position of the edge of the basetape vs. the side of the rim, this lets me adjust position as i go and get it on straight as possible before any final correction

practice with dry rim/tub a few times to get a feel for the process

by Weenie


jlok
Posts: 463
Joined: Tue Jun 30, 2015 3:30 am

by jlok

thank you sungod. I just realize that the dried glue is tacky rather than sticky so it's ok to touch (and as you said no need to touch).

jlok
Posts: 463
Joined: Tue Jun 30, 2015 3:30 am

by jlok

guys... I failed with my first attempt to install the tire. Any advice for me?

Mastik One

1. Vittoria corsa tire 170psi stretched on Bora One 50 rim (2017 24mm wide), wait for 24hrs,

2. rim and tire both one layer, wait for 24hrs,

3. rim one more layer, pumped the tire to 10psi and install tire right after, centered it, pump it up to 160psi, wait for 24hrs,

4. deflated and tried to pull it off by hand, found that the tire was not 100% sticking from the edge... disappointed of course...

results as below... I think the big problems are that I didn't use enough pressure pulling the tire down from the valve... and 1 UNEVEN layer of glue is not enough... sections around valve hole just didn't stick.....

can I try again with the current condition? is the tire shot?
I got the effetto mariposa carogna remover. Should I use it on the rim to clean and do the gluing again? Want to try 2 layers... real nice and even......

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sungod
Posts: 1500
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

from the pictures, a few comments/suggestions...

the tub is fine, wipe the tape/glue over with a clean cloth and some acetone, just to remove any trace of grease, then give it another coat of glue, the areas where the coating on the basetape peeled off may be a bit 'thirsty', be prepared to touch them up with an extra layer

if there're large areas where the rim is bare i'd suspect it still had some mould-release compound/other contamination on it, in which case strip it, clean thoroughly and reglue - fwiw on a new rim i use some 0000 steel wool to help scrub the surface of any waxy compound (this is not to roughen it, and don't go mad and take off the clearcoat), then use acetone and/or isopropanol with clean paper towels to scrub it until the towels stay clean

if the glue on the rim is ok, just put an extra coat on, working it in to the previous layer, let it dry a few minutes, remount

once the tub is on and lined up, i deflate it and then using a pole/other long blunt 'edge', roll the wheel along it applying pressure to force the basetape hard against the rim, then inflate, final check alignment is still ok and leave it to dry

try inflating to a lower pressure than you used, say 6 bar, if the rim/tub profiles don't match then very high pressure may tend to lift the basetape away from the rim either at the centre or the edges

with the current corsa tubs, i found i had to apply a lot of pressure at/around the valve area as it bulges a bit more than, say, veloflex ones, the bulge can result in a 'tic' each revolution - the first time i used them, after a few days i had to take them off and reglue as it was so annoying on quiet roads

when remounting i first pressed down hard on the valve area with the heel of my hand, then got the tension as high as i could while getting the tub on, being more generous with the glue for 3-4cm each side of the valve may also have helped, either way both wheels were then 'tic' free

Geoff
Posts: 5097
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

I think that I would tend to agree with @sungod.

It looks like you still have some mould-release compound on the rim, which accounts for the fact that the glue has adhered well in certain sections, but not in others. I would recommend stripping it off. When you clean that rim, I would recommend that the last wipe be with a clean rag, not a paper product, which can leave a residue itself. When you apply the first layer of glue down on the rim bed, don't be afraid to get a finger (wrapped with a piece of poly or a heavy plastic bag) right in there. I find that going back and forth with a finger does a far better job than a brush. Getting a good series of thin, even layers on the rim bed is the 'secret' to a good glue job.

I would add that I prefer to add more layers of glue to both of the basetape and the rim than you have used. I find that I get better coverage of the rim bed, in particular. Again, I find that a finger is the best applicator for glue, as you can 'feel' the glue going into the rim bed and the basetape. Your finger will help to get the glue 'in', rather than just 'on'.

jlok
Posts: 463
Joined: Tue Jun 30, 2015 3:30 am

by jlok

I removed all glues with Carogna Remover then cleaned the rims using acetone on a cloth.

Put 2 layers on tires, 1 layer on rims using a brush. (yes I shall trying using fingers next time)

Put the last layer on rim before mounting. Extra pressure was applied at valve and then pull side way and mount. Final sections proved that I didn't pull hard enough and sidewalls around that area were ruined somewhat by the glue. Mainly cosmetics issue, no big deal.

Inflat just enough to center the tire. The tire centered itself somewhat when pressure increased.

After that I forgot to deflat and apply pressure at center of the tire and pumped to 7bar straight away. Rolled it with pressure from my body to the skewers.

Now the tires are 400km old, no issue so far. Thanks all for the help. Now I wanna ride as much as I could to wear them out and try again.

Geoff
Posts: 5097
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Again, I recommend more layers of glue down on the rim, as thin as you can get them. Good luck!

xmashx
Posts: 25
Joined: Wed Mar 15, 2017 12:30 am

by xmashx

Guys, I have this one tiny issue that freak me out.
4 on 5 glueing I have sticky valve area. I can hear it all the time. How to avoid it? Seriously.
My only thinking is that maybe after glueing wheels stay unridden for even few weeks. Is that can be an issue? It's usually on the front wheel. The worst thing is that 2 guys tried with the same results. Obviously different rims, different tubs.
Someone recommended me to put a tape around valve to minimise area between valve and rim hole. Does it make sense?

Geoff
Posts: 5097
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

That is a surprisingly common complaint.

The best way to deal with that issue, as with almost anything, is by prevention. I find that the problem usually results from the area around the valve stem not being seated along the rim bed. Sometimes, this is the result of the manufacturing of the tire. If the rim tape is not installed along the caseing with the hole for the valve stem evenly-spaced around the stem, it can result in that spot pressing-up on the valve stem on one side or the other, resulting in a 'rattle' or a 'buzz' as the stem vibrates against the rim. If you trim the basetape around the stem with a razor (obviously, very carefully), this can prevent the basetape from putting uneven pressure on the stem. If you still have an issue, you can try to 'shim' the valve stem with a wrap of tape.

Once the tire is mounted, though, you cannot do anything preventative. Sometimes, a wrap of tape or a rubber or silicon 'O'-ring will do the trick. Some say a shrink-tube will work, too, but I haven't tried that.

Good luck!

xmashx
Posts: 25
Joined: Wed Mar 15, 2017 12:30 am

by xmashx

Thanks for the reply. Yeah, and the problem is that most of the rims don't have an extra space for the base tape around a valve stem. I even made a larger holes in carbon once to avoid it bumping in this area. That was while I used Conti Competition that actually didn't have that much issue with "buzzing" but rather bumping but still.

My common tubulars now are Vittoria Corsa that I use for HED Stingers (few models). But the same issue I have with Veloflex Records attached to Mavic iO or Tufo S3 Pro on my disk wheel.

My understanding is to cut base tape as I marked it on the picture, right? How much can I cut here without destroying anything? :)
Image

Geoff
Posts: 5097
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

Yes. that is exactly what I was referring to.

Usually, the simple solution is to take a very sharp razor and trim-away the excess basetape that portrudes up along the side of the valve stem. The idea is to remove enough for the basetape to be flush around the entire circumfrence of the valve stem. Whilst you are removing the excess basetape, keep in mind that the tire, once inflated, will curve-inward and have the tendancy to 'press' more of the basetape toward the valve stem, so you may need to trim-off more than you initally think. You can test your work by inflating just enough to round-out the tire, then curve the basetape as though it were on the rim bed. If there is still too much basetape remaining, you will probably be able to see it bunching-up.

I also forgot to mention that, in my experience, the best way to get the glue to spread around the valve stem (both at the basetape and on the rim bed), is to use a finger covered with a piece of poly.

xmashx
Posts: 25
Joined: Wed Mar 15, 2017 12:30 am

by xmashx

Thanks for all the tips. I really appreciate it.

alicekou
Posts: 2
Joined: Tue Dec 26, 2017 7:18 am

by alicekou

CarlTroy wrote:
Wed May 30, 2012 5:30 pm
To remove old glue : Finish Line's Citrus Degreaser! All natural! Strong as fark!

My way of doing it : Soak the glue in the degreaser for around 10 minutes, then use a metal scrubber ( used for washing dishes ) to loosen it, then wipe the goo off with a cleaning sponge ( with the smooth side ). Repeat 3-4 times and your there! :welcome:
Is there any requirement for cleaning sponge? Can I use silicone scrubber as an alternative?

Nefarious86
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by Nefarious86

Your link has gone PinaRene, care to post It, I'm curious.

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PinaRene
Posts: 534
Joined: Mon Feb 12, 2007 12:08 pm

by PinaRene

Nefarious86 wrote:
Thu Apr 12, 2018 12:00 pm
Your link has gone PinaRene, care to post It, I'm curious.

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It's back. But please do the thunb test after 24h like you would normally do with a glue job. :smartass: In fact the tubular tire glued in the youtube is still on my sons bike. Did 3 weeks of Alp rides with it - rode it to France on a 250 km ride from home ( one day ride ) and last week we did a part of the Tour the Flandres with all the cobble climbs. And they are 22mm Mavic tubulars :wink: .

by Weenie


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