Huggy in the workshop tech article – tubular tyre gluing

There are few things steeped in as much mysticism as the dark art of tubular tyre gluing. The process being fairly laborious is probably one of the main reasons people tend to avoid using them. The other main considerations being the expense of replacing a whole tyre as opposed to a tube every time you get a flat and what to do if it happens in the middle of nowhere.

That been said, when it comes to weight, acceleration and handling, tubulars are the ultimate choice and is why they are used by the pro’s. Another handy feature is that they don’t pinch flat like a clincher does. This makes them very appealing for cyclocross and allows you to run a lot lower pressures for extra grip.

Over the last couple of months I decided it was probably about time to mount my new set of tyres on the bike before the forthcoming racing season. I thought the 6 months before the racing season would be the perfect time to learn the art and lucky for me I did. There are some great resources on the internet and the general process I followed is detailed in the zipp video clip.

While this is a good resource there are some points I really wanted to emphasize, which hopefully will help you avoid making the same rookie mistakes I did. So at length here is the process and the lessons learned.

 

1) Old Glue Removal
Your first stumbling block is going to be what to do with the all the old glue left from your last tyre. You have 2 options: remove it or just apply more glue over the top. A lot of people don’t bother removing the old glue. Indeed, it seems some of the pro teams just remove as much as possible with some general implement and then whack some new glue over the top. See the mechanics in action here:

I can relate to this approach, removing old glue can be an extremely time consuming and frustrating activity. In my endeavors I too often contemplated abandoning the process or throwing my wheels over the balcony. This is before I stumbled on the product “Goof Off” – this stuff works a treat!

My first approach was to use acetone. I found this to have some cutting power but it evaporates so fast it can be really hard to get enough of the solvent to break up the glue. I estimate “Goof Off” to be about 5 times faster than acetone. Goof Off does not evaporate as fast as acetone and hence soaks into the old glue a lot better. You could probably remove all the old glue in about an hour per rim.

Get some of this stuff, 1 million times better and faster than acetone

Get some of this stuff, 1 million times better and faster than acetone

The other standard avenue is degreaser. I didn’t have much luck with this approach either, the degreaser does not evaporate as fast as acetone but it doesn’t have much cutting power. Don’t confuse “Goof Off” with its weaker less useful sibling “Goo Gone” which is a citrus-based degreaser. You would probably better off just using your saliva by spitting on your wheel and rubbing it. If you do magically somehow get it to work you will need to remove the oily film residue with acetone prior to glue application.

I have heard of but did not test the approach of leaving the rim to soak in degreaser by applying the degreaser to the inside of an old tubular and then mounting that to the rim to trap the degreaser inside and then leave overnight. Be careful not to degrease your meilenstein obermayer stickers off your wheels at $6,000 a set you want to be sure ppl know what wheel your running. Similarly, explaining to Paul Lew why he needs send you new stickers for his 700gr, $15,000 Boron Fibre wheel sets would be equally embarrassing.

I’ve heard of many other techniques to remove the old glue, most of which most sound both risky and entertaining, they include but are not limited to: heatguns, dremels, wire wheels and sharp implements.

My two cents on the issue is if you are spending considerable amount of time doing the process, you might as well remove all, the old glue, if I haven’t convinced you see if you can spot the textbook de-lam in this video. Some of you might also remember Josheeba Belokis spectacular delam. I should note that in both instances the bikes have a fairly wild attitudes when you look at the slip angle of the tyre with respect to the road, it could be argued the delam is not the root cause of the incident.

So having saved you a heap of time, having followed my advice and purchased some “Goof Off”, you should now have a set of clean, glistening set of tubs. Your next step will be the gluing process.

… and voilla! Glistening rim with prisitine surface to achieve your max bond strength

Tubular rim with old tubular glue, note the toe hold foot technique to hold the rim in place…. unorthodox but effective!

Apply a little “Goof Off” with a rag and ……….… Voila! Glistening rim with pristine surface to achieve your max bond strength

Apply a little “Goof Off” with a rag and ……….…
Voila! Glistening rim with pristine surface to achieve your max bond strength

2) Stretching your new tubulars.
I can’t stress this enough: the longer you leave these bad boys pumped up to max operating pressure and glueless on your rims the better. I would say 2 weeks minimum. Obviously, you want to time this with a slump in form or an absence from racing. Or as in my case, my first effort stunk so bad that after ripping them off and removing the glue (again) and being completely fed up with the whole thing I let them sit on my rims and pumped them up every so often for a couple of months (I was that furious, it took me a while to come around to having another crack).

Un-stretched tyres will really exacerbate any mounting issues and amplify your amateur abilities in the workshop. This is where I made my first error only leaving them for 1 or 2 nights. When it came to gluing:
• I struggled with the tyre. All my freshly applied glue went on my hands, the rims sidewalls, kitchen floor, clothes and anywhere but the rim bed. Working with an appropriately stretched or “aged” tyre will make everything easier.
• Wheel Hop / Egging – When mounting the tyre, place the valve in the hole and stretch the tyre outwards from the valve to ensures the tyre is stretched evenly around the rim and allow you to get to the final bit of tyre on easily over the rim, opposite the valve. If you don’t do this you will find that you have too much tyre at the valve hole and where you really struggled with the final last bit of the tyre on the opposite side to the valve, the tyre has been stretched locally and is hence “thin”. The end result will be an egg shaped tyre with a wheel hop at the valve. Again a tyre that hasn’t stretched for as long will make this issue far more pronounced.

 

3) Assess how the valve seats at the rim bed.

Some tyres and rim combinations seem more problematic than others. Most notably my Vittoria Evo Corsa CX’s seems to have a bit of build up around the valve. I decided to countersink my carbon rims at the valve hole just a fraction to help the seating of the valve. I used a metal countersinking bit from the hardware store and only very gently by hand. I am not intending to inform the design department of Reynolds, who probably spent 100 engineering hours coming up with the appropriate sized hole and would no doubt explain to me how I have voided the warranty.

 

4) Glueing your tubulars

Okay you’re a pro now, you’ve seen every other battler give it a go now it’s time for them to clear out of the way and let the you show ‘em how it’s done.

The general process is (having let the tyres stretch for 2 weeks)

Day 1:
Apply 1 thin layer of glue on the tyre and 1 thin layer of glue on the wheel, leave overnight. You will need a cheap appropriately sized paint brush and some Vittoria Mastik 1 cement. Supposedly the most proven cement out there, don’t believe me, check out the research done by some guy with far more time on his hands than I.

Day 2:
Apply one thin layer of glue to the rim bed, starting at the valve hole such that you have reference point, again leave overnight.
Note that the research indicates the most effective portion of the rim in terms of the wheel roll-off strength is actually the glue on the outer periphery of the rim bed, not just straight down the guts where all the spoke holes are.

Day 3: Game Time
This is what it all comes down to, performing under pressure! Days or possibly weeks of prep have resulted in the final and most critical step in the process. Mounting the tyre onto the quick drying cement.
Apply another thin layer of glue onto the rim bed.
Inflate the tyre only enough for some shape or “body”. It should be easily squeezable; you can always let a little pressure out if you find it too hard to mount.
Place the valve in the valve hole of the rim and stretching away from the valve hole as you go. Stretch the tyre onto the rim, ensuring that the tyre is going on quite evenly, you should be able to see equal amounts of base tape on either side of the wheel. If you pre-stretched your tyre for many days and were stretching the tyre outwards from the valve as you were putting the tyre on, you should be able to get the final bit of tyre on without a whole deal of hassle.
Inflate to about 20 psi and now it’s time to seat the valve firmly in the valve hole. You can do this by placing a rake or broom handle on the floor and using the majority of your weight to pressing the tyre and rim combination into the broom handle. The concavity of your rim bed and the handle should match up nicely and really bed the valve nicely into your rim. Having done the areas local to the valve roll the wheel along the handle such that you now seat the rest of the tyre onto the rim. This procedure is designed at seating the bits of trye out near the side wall to the outer portion of the rim bed, remembering that this is where the bond strength is critical for your tyre not rolling off as you draft that truck around a sweeper at 80kmh!
Put the rim on your bike or truing stand and assess if the tyre is on straight both laterally (i.e. no side to side wobble and any hop or egging of the tyre). A stick of chalk can be held firmly against the frame and will be a good gauge to evaluate any hopping or side to side wobble, marking any areas that are high and need re-alignment. Man/woman-handle the tyre as necessary to straighten it up by twisting the tyre or stretching areas that are high or low. Spinning the wheel just by holding it by the axle in the air will mislead you into thinking you have wheel hop when really it is just an unbalanced wheel owing to the extra weight of the valve.
If everything is working nicely inflate to full pressure and allow it to dry for 48hours before putting 4G corner loading into on the last lap at the weekend crit.

 

 

Hopefully this article provided you with enough information to glue your own tubular tyres. As always, please feel free to post comments and suggestions and start the tech discussion. Blotto members might want to consider sharing some of their innovative technical solutions.

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