Tubular Gluing Fail

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Dekkars
Posts: 6
Joined: Sun Jan 11, 2015 3:34 pm

by Dekkars

Hey All,

So I recently got myself a new pair of carbon tubulars from a friend. I read everything I could find on the subject (including the forum post here) and was pretty confident I could do it. Last night I did the final glue and attach on one of the wheels, and it didn't go very well...

Overview of what I did
24hr stretch at 140 psi
1st Glue of rim / tube + 24hr wait
2nd glue of rim / tube + 24hr wait
3rd glue of rim, wait 5 minutes, put tube on.

Last step got me, I couldn't get the tube on the wheel and when I finally did it was twisted and nowhere near even. I spent about 20 minutes straightening it out, which amounted to basically prying the tube off in sections and evening it out. At this point I doubt the glue is going to stick well, but it is curing anyway.

What did I do wrong? After I stretched out the tire I did a test and noticed that it went back on easily. Now when it came to actually putting it on it took me ten minutes and some very sore thumbs.

Also if the tubular doesn't stick, I'm assuming I can get it off, start over, and do it correctly. What is the best way to get it off, and how would I go about re-doing the work? Do I have to re-glue everything or only the final step?

This isn't over, and I'll get it eventually, but I need a little advice
-Dekkars

Edit: So apparently continentals are especially painful, and usually need to be re-stretched after gluing. This pretty much explains everything.

Greg66
Posts: 231
Joined: Mon Sep 26, 2005 8:06 pm

by Greg66

Take this with a pinch of salt, perhaps, as I have a grand total of five gluings under my belt...

I've found that the third application of glue to the rim works better if it is a little bit "generous". If it is very thin, it will dry more quickly. The tyre is easier to work once on the rim if the third layer is still quite wet when the tyre goes on.

And it follows from this that I don't wait five minutes after that final layer has gone on. In fact, I don't even take the time to screw the lid back on the tub of glue...;-)

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bm0p700f
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by bm0p700f

I apply the glue to rim leave over night and then apply another layer to rim and tub and leave over night. The following day I mount I find this gives a strong bond and glue does not end up all over the side walls. To get the tub to mount you have to manually stretch the tub from the valve hole toward the opposite end of the rim. Then it should mount without to much difficultly.

conti tubs are more difficult to mount but is possible by mortals. Try again, just apply some glue to the rim and tub leave over night and mount. there should be enough glue on the rim after you pull the tub of for that to work.

Oh the more glue you have the firmer the bond and the lower the rolling resistance is. there was a thread on this once.

campbellrae
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by campbellrae

@ bm0p700f - Interesting, so you don't put a final coat on the rim just before mounting the tyre?

mattr
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by mattr

I do two or three coats on both rim and tub.
Then a final thin coat to help everything move around.

bm0p700f
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by bm0p700f

not any more as I found trying to mount conti tub with a fresh layer of glue meant glue ended up all over me and the sidewalls of the tyre. Doing it the revised way still leaves a very strong bond (on my HED rims I have to use a tyre lever to ease the tub off) and glue does not end up on me or the sidewalls. Win Win.

Oh the tub can be moved around without issue allowing me to centre it (I inflated it to a 10 psi or so to give shape). Mattr the ammount of glue you use if fine but I tend to put very thick layers of glue down. with 30g of glue on the rim I think that's probably enough if I have to use a tyre lever to get the tubs off.

kevhogaz
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by kevhogaz

I've found putting a strip of electrical tape around the brake track of the rim, prevents getting glue on their. After I get the tire mounted, I just peel the tape off. No mess!!

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Calnago
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by Calnago

Vittoria Mastik.
Day 1: Thin layer on rim. One layer on base tape. Set aside.
Day 2: Second thin (and last) layer on rim. Mount tubular. Straighten as needed. Inflate. Roll hard and side to side.
Day 3: Ride

Bond is strong as it gets. I've experimented using more layers, but it's contact cement. More layers are not needed and I would argue they ultimately create a weaker bond, but certainly no stronger. It's the pressure (contact) you want. More glue than enough to make contact just makes things sloppy and has the potential to create a soft mess if things get really really hot. I carry a very thin "pry bar" with me in the event I have to remove a tire on the road, plus a short, round shafted screw driver which I insert between the tire and rim (after I'm able to pry the tire away from the rim enough to insert it), then roll it back and forth all the way around to break the bond. Still takes me 15 minutes just to remove the tubular it's so stuck.
The two layers on rim, one layer on base tape method using Vittoria Mastik I described is what Vittoria themselves also prescribes. It works.
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bm0p700f
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by bm0p700f

Maybe some can help here. The is a poster who responded to rolling resistance thread a while back. The poster is well known and I think has done some rolling resistance work and the upshot was that how much glue is applied does have impact on rolling resistance. The stronger the bond the lower the car and more glue was indicated to work. Can anyone locate this thread or the poster post it here.

sungod
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by sungod

bm0p700f wrote:Maybe some can help here. The is a poster who responded to rolling resistance thread a while back. The poster is well known and I think has done some rolling resistance work and the upshot was that how much glue is applied does have impact on rolling resistance. The stronger the bond the lower the car and more glue was indicated to work. Can anyone locate this thread or the poster post it here.


sounds like the notes on gluing here...

http://www.biketechreview.com/tires_old ... g_rev9.pdf

...pretty much in line with fdegrove in the tub thread i think

i glue like this, it can be a bugger getting the tub off, the bond basetape to rim is often stronger than the basetape to tub (veloflex)

wrt glue getting on the brake track/sidewalls, i used to get this, but can now mount tubs without it happening, so maybe a practice/technique thing

mdeth1313
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by mdeth1313

I stopped trying to mount tubulars with a fresh coat of glue on the wheel years ago. I do 1 or two layers to the wheel and tire and after everything has dried, spray the wheel with water so the mounting surface is nice and wet and then mount the tire. The water allows you to center the tire without as much resistance and I have never rolled a tire so it works just fine. Once the tire is mounted I ride it straight on my driveway, then let it sit for at least a few hours (overnight is better) and then it's on.

I've been riding tubulars since 2006 and I think I started using this method around 2009.
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Dekkars
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by Dekkars

Hey all,

Thanks for the advice, I was able to get the tyre off, clean it up a little, and put it back on. The glue seems to be holding perfectly this time.

However, there is one spot where the glue is a little less than perfect. I think I missed a small spot, but you can see where the tire isn't glued to the sidewall, there is a small 'hole'. Is it legal to just brush a little glue in there and let it set again? Or is that something I should never-ever do and I need to start again.

Thanks,

-Dekkars

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Calnago
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by Calnago

Ha... I don't think anyone with throw you in jail. And since it's just been glued and a bunch of dirt hasn't worked its way in there, if it were me that's certainly what I try first as opposed to ripping it off and doing it all over... just try to add a little glue the gap, depending on how big the gap is (use your judgement here). But this was a good learning lesson... to emphasize how important it is to get the glue all the way up the edges of the rim, since that is where the bond will be most stressed. After a while, you develop a technique and it will go much smoother and be a rather peaceful process, as opposed to a nerve racking exercise in timing and stickiness and sore thumbs.

I don't use Continentals anymore simply because they are so damn tight and difficult to get on (even with a good prestretch). I've been using Veloflex exclusively and they are so much easier to mount. Also, the Conti's have a very absorbent cotton base tape, so I've actually used two coats of glue on their base tape before, just because it seems to soak it up so much more. Happy riding!
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beanbiken
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by beanbiken

mdeth1313 wrote:I stopped trying to mount tubulars with a fresh coat of glue on the wheel years ago. I do 1 or two layers to the wheel and tire and after everything has dried, spray the wheel with water so the mounting surface is nice and wet and then mount the tire. The water allows you to center the tire without as much resistance and I have never rolled a tire so it works just fine. Once the tire is mounted I ride it straight on my driveway, then let it sit for at least a few hours (overnight is better) and then it's on.

I've been riding tubulars since 2006 and I think I started using this method around 2009.


That is a method I have not seen before...............but one I will certainly give a shot next time round.

Steve
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Kendogz161
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Joined: Sun Jan 18, 2015 10:17 pm

by Kendogz161

Dekkars wrote:Hey All,

So I recently got myself a new pair of carbon tubulars from a friend. I read everything I could find on the subject (including the forum post here) and was pretty confident I could do it. Last night I did the final glue and attach on one of the wheels, and it didn't go very well...

Overview of what I did
24hr stretch at 140 psi
1st Glue of rim / tube + 24hr wait
2nd glue of rim / tube + 24hr wait
3rd glue of rim, wait 5 minutes, put tube on.

Last step got me, I couldn't get the tube on the wheel and when I finally did it was twisted and nowhere near even. I spent about 20 minutes straightening it out, which amounted to basically prying the tube off in sections and evening it out. At this point I doubt the glue is going to stick well, but it is curing anyway.

What did I do wrong? After I stretched out the tire I did a test and noticed that it went back on easily. Now when it came to actually putting it on it took me ten minutes and some very sore thumbs.

Also if the tubular doesn't stick, I'm assuming I can get it off, start over, and do it correctly. What is the best way to get it off, and how would I go about re-doing the work? Do I have to re-glue everything or only the final step?

This isn't over, and I'll get it eventually, but I need a little advice
-Dekkars

Edit: So apparently continentals are especially painful, and usually need to be re-stretched after gluing. This pretty much explains everything.


You are on the right path just add some steps.
I see that you are mounting up Continental. These are one of the hardest tubulars to mount because they are so tight.
I ride and race on tubulars, this is how I mount them up Continental,

Mount them up on some stretching wheels (clinchers wheel work if that's all you have), inflate them to 140 psi and let sit for at least three days, longer doesn't hurt.
I use Vittoria Mastik One glue and apply an acid brush
On a new wheel I pass 120 - 150 grit sand paper to rough them up and clean with acetone. A use wheel just make sure the old glue is clean and even.
Put one coat of glue on the wheel and let sit at least 1:30 hours or longer.
I put one thin coat of glue on tire base tape, let dry of 1:30 hour then second coat on tire base tape and let that dry for 3:00 hours. The Conti base tape really soaks up the glue that's why the two passes.
With the glue dry on the tire mount is back up to your stretching wheel air up to 120-140 psi and let sit over night, this is the key. The Conti's lose some of the stretch while the glue is drying.
Put a second coat of glue on the wheel and only let sit for as long as it takes for you to take the tire off the stretching wheel.
With wheel on the floor and valve hole at 12 o'clock mount tire and pull down over wheel with most of your body weight, you'll feel the tire stretched.
After you put the wheel on you hips and mount the rest of the tire. Look at the tire base tape to wheel for evenness and inflate to about 40 psi.
Check tire again for straightness, the glue is still wet at this point so the tire will give.
After that inflate to 100 psi and roll wheel on the ground starting at valve. Make sure to push down with all your weight to seat that base tape to wheel.
Clean up wheel brake surface and side of tire and you are good to go.
:beerchug:

When I do it this way I always have trouble removing the tires and this is what I want.

You almost got just add that second stretch and mount the tire straight away after applying mounting coat on wheel.
Also you don't have to wait 24 hours in between coats, just until it's dry to the touch.
I do 1:30 hours as a guide line. I know guys that would glue up a set of tubs 2:00 hours.
I just don't skip on the stretching because the Conti's are so tight.

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