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Wednesday
Aug012007

Tubulars: Part III, Gluing the tire to the rim


As you may have gathered from Part II, repairing a tubular tire is a lengthy process; so too is gluing the tires to the rim. To do the job properly it can take several days to allow the glue to cure and the tires to settle on the rim.

You can’t just fit the tires and go out and ride immediately as you can with clinchers; it is necessary to plan ahead.

Let’s assume we are starting out with brand new tires and new alloy rims. I have no experience with carbon fiber rims so I can’t advise on those. I understand there may be issues with tires not adhering so well to CF rims.

Before you even apply any glue to the rims, mount the tires and inflate them to the recommended pressure, and leave them on the rims for at least 24 hours. New tires are extremely tight on the rim and you really have to “muscle” them on.

Once they have been on the rim and inflated for a period of time, the tires stretch out and are easier to fit the second time around. You do not want to be dealing with glue and trying to get a brand new tire on at the same time.

By the same rule, don’t forget to pre-fit and inflate a spare tire; because if you get a flat you will not want to be trying to fit a brand new, un-stretched tire, by the roadside.

If you can’t get the tire on the rim the first time, it may be necessary to stretch the tire by putting it over your shoulder, diagonally across your back, and the put your knee inside the tire and push on it.

Before you apply any glue to a new rim, the concave inside surface where the tire sits, needs to be roughed up. This is to make sure the glue bonds to the rim; glue doesn’t stick too well to a shiny surface. Use some coarse emery cloth, and just scratch up the surface.

There are two types of tire adhesive; double sided sticky tape, or glue in a can that you apply with a brush. Some people like the double sided tape because it’s quicker and less messy that the glue. I don’t like it for the simple reason, when it comes time to change a tire, I never know if the tape will stay on the rim, or come off stuck to the tire. Glue is cheaper, I get many applications out of one can.

Getting back to our brand new rims that we have just roughed up with emery cloth; apply a coat of glue with a brush. I buy cheap glue brushes that come in a packet of five for a little over a dollar, and are cheap enough to use once and throw away.

When I apply glue to the rim, I deliberately miss a spot. The space between two spokes that is opposite the valve; that is the place where the manufacturer’s label usually is. (I am not talking about the new wheels with a large space between spokes. About 2 ¼ inches [56 mm.] is good.)

The reason I do this is, if a tire is stuck on correctly, it is hard to remove, even when deflated. This little dry spot with no glue gives me a place to start. The tire will not roll off because 2 ¼ inches of glue is missing. I choose the space opposite the valve so I remember where it is.

The first application of glue should be allowed to dry overnight. The next day, apply a second coat and allow to sit for 15 minutes. The tire manufacturers will tell you to apply a coat of glue to the base tape of the tire; I do not do this. I find it hard enough to get a new tire on a rim, with glue on it, it gets on my hands, then all over the sidewalls of the tire and the rims. Just a horrible mess.

What I do is; I put the tire on after two coats of glue to the rim. Inflate it and allow it to sit for several hours or maybe overnight again. Then I remove it and give the rim a third coat of glue. (The recommended initial amount.)

Now the tire has glue residue on it because it has been on the rim, but not as much as if I had applied it with a brush, plus the glue is partially dry. Also, because the tire has been on and off the rim twice now each time it gets easier to put on.

On the final fitting, I spin the wheel and make sure the tire is aligned. Partially inflate, and look at the edge of the base tape. Is there an even amount showing all around the rim, and is the tread central on the wheel? If satisfied the tire is straight, I fully inflate.

After allowing the bike to sit overnight, on the initial ride the next day, I take it easy and not push my speed to the limit on corners. By the next day, and after riding the bike, the tires should have bedded down and the glue should be cured.

A final test is to physically try to roll the tire off the rim with both hands and pushing with the thumbs. This is the test that officials will perform before a race. If the base tape lifts at all from the rim the tire is not sufficiently glued.

Whether you choose glue or double-stick tape, both types stay tacky for a long time. This means the tire can be removed when necessary, and if you change a tire on the road the glue is still tacky and will hold the tire well enough to get you home. (Riding with caution of course.) Once you get home you can remove the tire, give the rim a fresh coat of glue, wait 15 minutes, replace the tire and after the bike sits over night, you are good to go again.

At least once a year, or sooner if you make several tire changes, it will be necessary to clean off the old glue and start over. Use any kind of paint solvent to do this; I use lacquer thinner, it is probably one of the least toxic. Once the rims are clean and dry, start over as you would for new rims, although it may not be necessary to rough up the rim surface again.

Disclaimer: I have just explained how I fit my tubular tires. I have never had a tire roll off, but I weigh about 150 lbs. It would be remiss of me if I recommended you follow anything but the manufacturer’s instructions.

As I have often said, I am retired from the bicycle business, I have no connection with any company and I am not trying to sell you anything. I have given you the pros and cons of tubular tires. This is free information intended only to assist you in making your own decisions as to what type of tires you use.

Some of you have been asking about wider tubulars. Vittoria makes the Pave EVO CG, 24 mm wide, and the lower price Vittoria Rally training tire is available in 23 mm. Also, although tubulars are designed to be inflated to 120 psi or more, I find at my weight 100 psi is ample. Like the Sleep Number bed, find your own comfort level.

Footnote: This is the final in a three part series on tubular tires. Here is a link to Part 1 and Part 2.

Monday
Jul302007

Tubulars: Part II, Repair


Tubular tires can be repaired, I have done it often, but it is a lot of work. The first obstacle is pulling the base tape away from the stitching.

This used to be an easy matter, but I’ve noticed in recent years with modern adhesives the base tape seems to be permanently bonded to the tire. What I do is pick at the edge with my thumb nail and try to lift just enough of the base tape that I can grasp it with a pair of pliers.

The object is to try to pull the base tape away from the area where the puncture is, but leave it in one piece attached to the tire. In reality, what will probably happen is the base tape will tear off in a short piece.

You will notice this is what happened with the tire I opened up to take these demo pictures. Not to worry you can still glue it back in place after the repair. The next important trick is to find exactly where the puncture is, and only cut about 2 inches (50 mm.) of stitching. An Exacto Knife is the perfect tool for this job.

Under the stitching, is a thin fabric strip or membrane that is lightly stitched to either edge of the outer casing. This strip of fabric is there for two reasons. It holds the inner tube in place while the outer casing is being stitched during manufacture. It also prevents the thin latex inner tube from chafing on the stitching.

Carefully cut the stitching on one side only of this fabric membrane, and pull it to one side to reveal the inner tube. (See picture, below. The fabric membrane is white, the inner tube is green.)


Pull the inner tube out in a loop and the puncture can be patched in the usual way. Before you put the tube back in place, inspect the inside of the outer casing for any sharp objects sticking through that could re-puncture the tube. (This is standard practice with any puncture repair.)

Also, inspect the outer casing for damage as shown in the next picture (Below.) In this case, it will be very important to glue a piece of canvas on the inside, because with 120 lbs plus pressure in the tire, there is a good possibility of a blow out later. Notice I use a piece of rolled up cardboard to hold the inner tube out of the way while I glue the canvas in place.

Canvas can be bought from any fabric store, and any proprietary brand of contact adhesive is good for gluing it. Follow the adhesive instructions, usually you coat the canvas patch and the area inside the tire casing, allow to dry 10 or 15 minuets, then stick the patch in place. Allow it to dry thoroughly (Preferably overnight.) before you put the tube back inside.

There is no need to re-stitch the fabric membrane back in place as long as it is put back over the inner tube, between the tube and the stitching. It will stay in place because you have only opened up two inches or so.

Sewing the tire up again is the biggest chore. You need a sail-makers needle, which is tri-angular rather than round in section. If you buy a proper tubular repair kit, it will come with one of these. (Google: Velox tubular tire repair kit.)

You will need a metal thimble to push the needle, and I use a pair of needle-nose pliers to pull the needle all the way through. If you managed to repair the puncture by cutting only two inches of stitching, you will be glad you did when it comes time to sew it up again.

Try to use the original needle holes to re-sew if you can, and use the same original cross-stitch pattern. If you open up more than two inches of stitching there is a possibility you will not re-sew the tire straight, and you will have a twist in it.

Glue the base tape back with the same contact cement used for the canvas patch. If there is a cut in the rubber tire tread; glue it with the rubber cement that comes with the repair kit. Allow the cement to dry overnight before inflating the tire.

Part 2 a three part series; here is a link to part 1, and part 3.

Friday
Jul272007

Tubulars: Part I


A regular reader of this blog recently asked me if I would write a piece comparing tubular tires to clinchers.

My first reaction was that I am not qualified to do so because since I started riding seriously and racing in 1952 to this day, I have ridden tubulars exclusively.

How can I comment on the ride quality of a modern clincher tire when I have never ridden on them? I contacted a good friend Steve Farner, who lives in Southern California, for a second opinion. Steve has ridden and raced in the 1970s through the 1980s. In an email he wrote:

"I've noticed pro teams in the Tour that are using tubulars, even if they are sponsored by clincher tire companies, discreetly glued to tubular rims with other makers' names affixed. Seems many pros will use tubulars (even not admitting they do); I think they prefer the feel and ride compared to clinchers, in spite of manufacturers' claims they are the same now. I also use tubulars and will never ride clinchers; they don't compare. It is easier to manufacture clinchers and that is a big reason for the push to race clinchers, not at all because they are better. Thus the deception racing on tubulars instead of clinchers."

Steve makes a valid point about the cost of manufacture. I ride on Vittoria Evo Corsa CX tires; they cost me $47. (See top picture.) This is a top of the line tubular and they can go for twice that amount. I shop around.


From the same source, I could buy a Vittoria Diamante Pro clincher tire for $31.57. (Left.) Add the cost of the inner tube, (Included in the tubular price.) and the price is close. The big difference is the tubular tire is hand made, and the clincher I’m sure is manufactured by an automated process. There is bound to be more profit in the clincher tire.

Manufactures will tell you the ride quality and performance of the latest clinchers are the same as a tubular; they push the product that turns the most profit. Many tire companies don’t even make tubulars, so obviously they are not going to say their tire is inferior to another manufacturer’s product.

If pros and top amateurs still race on tubulars it is because the ride quality and the more important, the performance is superior. That is the way I see it, because pro riders will normally ride whatever they are paid to ride; all other things being equal.

If you are not racing, and not looking for a competitive edge, does it really matter? Of course not; a person rides clinchers for convenience; it is easier to fix a flat. (Puncture.)

Having said that, if I get a flat, I do like the convenience of being able to slip a spare tubular on the rim, without the use of tools, inflate it, and be on my way. A spare tubular folds up and fits neatly under my saddle, along with a CO2 inflator. In an absolute emergency, I can ride home on a tubular tire while it is flat, without damaging the rim.

They are lightweight, some can be inflated up to 130 psi so there is very little rolling resistance. At the same time because they are a complete tube, they absorb the shocks of riding over very rough road surfaces. They are extremely responsive and this is why they are preferred for racing, you make a sudden effort and the wheels and tires respond immediately.

The biggest factor in deciding whether to use tubulars is the cost. Not that they cost a lot more initially, but you have to consider the possibility of buying a new tire every time you get a flat. Some people don’t know how to repair a tubular tire, others can’t be bothered.


In my case, I ride purely for pleasure these days, so I ride tubulars because they give me pleasure in the way they ride. To me the cost is justified.

However, in researching for this piece, I discovered I can buy a lower price Vittoria Nuovo Pro TT tubular, still considered a racing tire for $22.78. (Left.) Alternatively, I can buy a Vittoria Rally training tubular for $15.77.

It is somewhat extravagant for me to be using one of the best tubulars available, when I am no longer racing. At these prices, it is less important to spend time repairing them. 

I should buy a few spare, because if a person can afford to do this, and they are stored in a cool dark place, like a closet; the rubber matures and becomes tougher with age; they wear longer and resist punctures.

If you have never ridden tubulars and are considering this, you will not be disappointed.

However, look on it as a possible high maintenance relationship. In such relationships you are let down flat a few times, and you wonder if it is worth it. Stick with it for the long term and you will find it is.


Footnote: Tubular tires are often refered to as "Sew-ups" or "Tubies" in the US, and as "Tubs" in the UK.

Pictures from Pro Bike Kit.

In part 2 I talk about repairing tubulars, and part 3, gluing the tire to the rim.

Wednesday
Jul252007

Vintage brake cable routing


If you own a vintage steel frame, chances are the rear brake cable is routed through braze-on cable guides along the top tube.

Every time the rear brake is applied the cable housing moves slightly. If it drags across the top tube, or touches the seat-stay caps, eventually it will wear through the paint.

To avoid this, route the cable so it is slightly above the seat lug, clear of the paint, and the cable housing rests against the aluminum seat post, as shown in the top picture.

Try not to have too big of a loop in the cable housing, or it will push the side pull brake off center.

To hold the cable housing in this position, place a small rubber “O” ring just behind the last cable guide.


Cut a groove in the plastic sheathing of the cable housing, with a sharp knife, so the “O” ring will drop in this groove and stay in place. See the close up detail shot above.

Use a # 60 “O” ring (¼” O.D. x 1/8” I.D.) These can be found in the plumbing section of your local hardware store.

Monday
Jul232007

On life’s journey

Paths cross and we meet
Face to face, hands shake
Names soon forgotten or never remembered
Faces stay a little longer.

Others meet on the Information Highway
Paths cross the same, often by chance
No face to see, no hand to shake
Just a name.

Either meeting good or bad
Mostly good, reflecting how people are
That is, mostly good
Lives are touched.

Some glance our way and move on
We never see them again
Others sharing a common interest
Stay a little longer