graphs

Instead of opening a new thread I'll ask here - anybody have an opinion on how often you need reglue a tubular tire?

I bought a lightly used wheelset last summer with conti comps already glued and only maybe a few hundered km on them. They've been stored, deflated, in wheel bags since October. The original glue job was good but I'm not sure if I should reglue them this spring. What is common practice?

jwible

If you can pull them off easily by hand then reglue. If the glue is getting brittle then I'd reglue even if the tire is still firmly secured.

jfmckenna

YEah just try and roll it back with your thumbs. IF it's dry then it's time to reglue. I've easily gone two years on cyclocross tires with Mastik One.

graphs

Alright, I'll check the glue and go from there. Thanks!

Psimet2001 

I charge $30/wheel. Many shops around here have stopped doing it due to liability.

I do a lot at a time usually. There is a bit of an art to it. I am not one of these "do it up in 30 minutes" kind of guy. I understand that can be done, but I have seen 2 separate studies that show bond strength over curing time and they both show that - Mastic 1 is the strongest and that the strength in the bond really tops off at 24 hrs. This is each coat if you do multiple coats. Doing it all up at once in rapid succession results in a bond that is about 50%-70% of the strength (IIRC....it's been a while and I would hate to look it up, but there is data, just give me some wiggle room).

Stu at CXWorld does his in rapid setup, but he uses Belgian tape. Belgian tape is great stuff....if you never want the tire to ever come off in 1 piece and you have hours and hours to spend cleaning the rim afterwards.

Is it worth paying someone or doing yourself?....I "made" quite a bit on gluing this last year. I also spend a stupid amount of time doing it. When my customers ask me I say, "Have someone else glue it if you really just aren't detail oriented, tend to make a mess of things, etc....but....if you ever roll it and go down - tough. If you can't stomach anyone else doing something that could result in you hitting the deck then suck it up and glue your own"

graphs

I feel that way about most bike-related things, especially components that are critical to my safety. I'd rather take forever and much trial and error to learn how to do it myself properly than leave it at a LBS where I have no idea who is going to do the work. There are really only 2 or 3 mechanics in town that I trust implicitly and unless I can be certain that they personally will do the work (instead of junior wrench, say) then I will just do it myself or wait until my go-to guy is free.

hammy56

yesterday I realized Im using alum glue on my carbon tubs. derrr.

whats the difference in the glues?

I know one thing's for sure, when I had to peel 2 of them off recently it was a beeitch...

Handelfan

Conti says that their carbon glue is more resistant to heating up when braking on descents. I'm not sure if there's much else. Every wrench I've talked to around here uses the "regular" glue, even on carbon rims, and they haven't had problems. Plus, I don't see any screaming descents in road races in my future.

graphs

Yesterday I pulled the old tubs off and there is only a bit of glue residue. Should I clean all the glue off my rims before gluing the tires back on? Presumably I won't be able to remove the glue from the basetape of the tires I am re-using ...

Homebrew01

Leave the old glue on there. The only time I make an attempt to remove glue is when there's a ton of it and it's old & crusty and not well adhered to the rim. Even then, I'll get rid of the "bad" glue, but not worry about the stuff that looks like it doesn't want to move.

graphs

Nah, there's not too much of it. It's pretty even distributed but there's no chunks or anything. In reality I probably could've continued to ride them as they were, tires were pretty tough to get off... but it's good to learn how to do it and I wanted to rotate the back tire to the front anyway for more even wear. Thanks for the help!

caloso

I asked the head wrench at my LBS. He said the Continental said the same thing: There's no issue in using "aluminum" glue on carbon rims.

jfmckenna

Leave the old glue on the rim. Take a piece of 80 or 100 grit sand paper and spin the wheel in a truing stand and sand the old glue. IT will heat up a bit and sort of melt in and you can get the chunky stuff off. Follow that by applying Goof Off solvent on the rim with a rag as you spin. Let that dry and you should have a nicely melted down flat surface. Apply coats to the tire till the base tape sponges it all up and all the pours are filled. Let that dry for a while, maybe even over night. then apply a coat to the rim dry 20 min, a coat to the tire, a coat to the rim and mount. A fresh rim would require more coats. When I do it like this I need tire levers to get the tire off.


BTW as far as old glue ups go... Sometimes the thing to look for is not necessarily how well the base tape is mounted to the rim but how well the tire is mounted to the base tape. I tend to find that that is more the problem with old glue ups. If it's parting from the tape a bit I've found a bit of CA (cyanoacrylate) glue will tack it down nice. Otherwise just use Mastik One.

Racer Ex 

I clean off the old glue on 95% of the rims, the exception being when I'm gluing the same tubular back on and I have a mirror image on the rim and tire and I don't have another tire handy or am pushed for time (I have some wheels that have internal nipples and needed truing or a spoke repair).

Preface this with: All I use is Vittoria Mastik, Conti glue may have some other properties I'm not aware of.

1) Glue relies on a molecular bond, the smoother the surface, the fresher the glue, the better the bond. It's designed with an optimal VOC ratio (VOC's being the "thinners" that evapoarate and give off the smell) to provide that chemical bond. Leaving old glue on compromises this bond in three ways (see 2, 3 & 4)

2) You can try to make old glue as smooth as you can, but it will seldom if ever be as smooth as the original rim surface coated with new glue. Instead what you're left with is a surface covered with peaks and valleys, diminishing your bonding surface area.

3) Mastik becomes brittle with age. So you're gluing onto a brittle surface that isn't providing as strong a bond.

4) What VOC's do penetrate the old glue don't recreate the optimal ratio and don't penetrate to the rim surface.

I want my tubulars to stay on, period. I also want the best possible rolling resistance, which is also compromised by the old glue and weaker/less bonding.

I've never seen the same bond strength when old glue has been left on the rim. My fresh/clean glue jobs are strong enough that they are almost always stronger than the original base tape...it's pretty inevitable that I'll end up with some base tape either stuck on the rim or pulled off the tire, even on almost new tires that I had to remove because of flats.

Takes more time and effort, yields a better result. It takes me 15-30 minutes to clean off a rim, for me that's a pretty good investment if the tire stays on in a high stress situation.

I've removed tires that have been glued with the Conti glue, they come off pretty easy. From what I've seen the stuff remains more pliable than Mastik, which might allow it to stay adhered at higher temps (if that's really the case).

I inspect my tubulars and wheels before every race. On my stage race wheels I glue new tires on every year and keep the old tires around as emergency spares or toss them if they are no longer serviceable or looking pretty worn.

jfmckenna

Racer Ex is right in theory but in practice I can glue a tire on a rim with old glue on it and I'm quite sure no one in this audience would be able to rip it off by hand. But if you do keep up with the practice of cleaning the rim every change then it's good housekeeping. Because eventually you will want to clean up the rim and it's kind of an ordeal when you have 1mm of glue built up. To clean the rims I use Goof Off and soak the surface with it and tack it off with a cloth, it will take several passes.

carpediemracing 

A local rider's father comes in here and gets Contractor Solvent to clean off their carbon/alum rims. Apparently glue just drips off the rim and leaves it "like new". The rider won cross Nationals (i.e. low pressure tires) recently so whatever gluing the father does works. The father swears by the stuff, gets many bottles at a time. I never tried it, but just passing it on.

graphs

Well, I ended up cleaning all the glue off the rims anyway. I'm kind of anal with things like that and being a tubular newb I wanted to see how hard it would be. I was able to clean both rims to a new looking state in about an hour using Goof Off.

There still however is old glue on the base tape of the tubs I'm re-using (if I could afford to put brand new tires on I would, but I can't, so I won't). I don't know what kind of glue it is so I'm hoping that it plays nicely with the Mastik One I will be using. I like to think that when I coat the base tape all the old glue will soften up and become one with the new stuff... wishful thinking perhaps but one never knows. I figure with 2-3 coats on the rim and 2 on the tire there should be enough glue to hold the dang tire on regardless of what kind was used before.

brian416

They'll probably be fine with old glue on the basetape. If it were me, I'd make sure to air down the tires after gluing and really inspect the bond just to make sure the tires won't be coming off.

Hida Yanra

a truing stand, a semi-circular-ish scraper of some sort (inverse-ish of rim bed), and a heat gun work wonders for cleaning glue off the tyre bed.
Don't heat up the wheel, just a bit of heat will make the glue soft and easily scrape-able. In fact, I just did this at work.

Sigh- time to glue up 3 sets of wheels.

graphs

I don't have a truing stand but placing the wheels gently in the in the trainer has been pretty handy for glue application.

graphs

oh boy, what a mess. glue all over the place - rims, sidewall, fingers... it's gonna take me just as long as it did to glue them to clean this mess

Homebrew01

First time gluing ? Quick suggestions:
Well stretched tire
Piece of scrap plastic over your fingertip when spreading glue
Some people tape the side of the rims, then peel off later
Pre-glue rim & tire, then apply final glue to rim. Easier to hadle the tire if it has dried glue.

Also, as you mount the tire, pull on each side away from the valve a few times to get as much slack as possible for the end.

graphs

Yeah it was my first time. The tires were already used so stretching wasn't necessary but still took a bit of work to get the last section on. I think my error was in doing the final layer of glue on the rim then the tire so the glue was pretty sticky still.

I ran out of glue so I'll do the rear wheel tonight and hopefully be a little less messy. I may try the tape on brake track trick until I get a little better at it. I will be worshipping at the altar of Goof Off later this evening.

I had wanted to rotate the back tire to the front but I got mixed up and they'll be the same as before. No way I was going to pull that tire off again because of a little wear patch...

jfmckenna

Definitely tape the brake rim with masking. I've been gluing tubulars on for years and I still do that as a precaution, literally takes seconds. Also make sure you get some surgical rubber gloves, don't even think you won't get the stuff on your hands because you almost always will.

Finally, be careful with the Goof Off when cleaning the rim sidewalls. IF you get any under the tire it will soften up your glue and I do believe it might also soften up the glue that holds the base tape on. So don't soak it. Just soak the rag and carefully wipe off whats needed.

graphs

Thanks for the tips. I had so much to do last night in such little time I didn't take the time to tape the brake track. This tire was a bit harder to get on but I made considerably less of a mess. Didn't wear gloves either but only got a little glue on me. As for the goof off, I only ever put it on the rag and then wipe. I was nervous about it affecting the glue but honestly there is so much friggin glue I don't even know if it would make a difference. Still, I will check the glue job tonight before I take them out for a spin and if there's any spots that don't look good I won't race them this weekend.

Even though my glue job doesn't look very pro I'm glad for the experience and I'm sure I'll get better with practice. My girlfriend said she'd pay to have the shop do them next time though