Tyre width for tubs?

vortice

My 20mm width wheelsmith tubs will arrive in a couple of weeks. Anyone know what width tyres will fit these rims? Is it similar to clinchers, where there is a degree of flexibility or is tyre size more critical?

Cheers.

Grill

Depends entirely on what you're looking to do with them. I stick to narrow on TTs >22mm and 23mm for everything else.

vortice

Thanks for the reply - so generally it's not that critical. So 23-25mm tyres would be fine on 20 mm tubs?

JayKosta

Yes, tubular tires aren't too particular about the rim width. But they do need to be glued securely to the rim.

I weigh 170 pounds and use tubulars (new, but 'old stock') which weigh 270-280 grams - I don't even know whether tubular tires currently list their weight as part of their specfications. The ones I use look about the same width as 23mm clinchers. I use them for general day rides, they are not overly lightweight or delicate, but I do watch carefully to avoid road debris.

When you get the rims and tires, BE SURE to 'dry fit' the tires on the rims and inflate them before you do ANYTHING with glue. Some tires are very tight on the rims and can be almost impossible to mount. Also be very careful of the valve stem when mounting the tire - I've gotten leaks at the valve because of miss-handling the tire while attempting to mount it.

With my new tires that I can't 'dry mount' on rims, I moisten the cloth base tape of the tubular with water, then wipe the surface water off of the tire - with the base tape a little wet, it seems to allow the tape to stretch enough so that I CAN get it onto the rim.

Let the tire remain on the rim at least over night, to make sure you'll be able to mount it with glue.

I don't pre-glue my spares (I carry 2), but I do pre-stretch them.

Jay Kosta
Endwell NY USA

vortice

Thanks Jay, some great tips there.

You don't pre glue your spare? You have no worries about the tyre rolling off the rim? Do you consider using the spare just to get you home or to continue with your ride?

JayKosta

My experience is that the residual glue on the rim, along with a tight-fitting spare is adequate for non-intensive riding. I wouldn't do highspeed quick turns, or highspeed descents, but I've not had trouble with them. I DO glue the replacement tire to the rim before the next ride.

To continue or go home ... I wouldn't continue on a long unsupported ride with just 1 spare - too risky to be stranded far from home. Flats in tubulars can be patched, but that would be extremely difficult away from home, and finding a place to purchase a new one would be very unlikely.

When I mount the tire on the rim, I align the base tape so it is even distance from the rim on both sides. Then spin the wheel to verify that the tread runs straight - make further corrections before the glue dries. And don't use too much glue (a real mess), just enough to give a very thin coat.

Jay Kosta
Endwell NY USA

Monty Dog

You need to pre-glue your spare to give it some sort of tackiness - but you'll still need to be wary. You could also carry tape, but it's more hassle. There's a good thread on glueing tubulars on weight weenies forum. For general riding I'd go for 23-25mm tubulars - the rounded carcass give a more progressive feel as your turn, plus bigger volume will help cushion against the inevitable potholes and irregular surfaces.

JayKosta

yes... pre-glue on the spare IS the 'standard method', and certainly would give a more securely mounted tire.
I choose to not pre-glue because my spares are tightly folded and strapped under the seat for long periods - e.g. months.

Jay Kosta
Endwell NY USA

andy_wrx

Answering your original question - yes, tyre size does matter : it's not critical on precise size, just so long as not too narrow or wide

If the tub is too narrow, then it'll fit to the well of the wheel but there will be gaps to the sides of the rim and it won't glue on brilliantly.
If it's too wide, then obviously vv (and particularly important with tape I'd suggest)
- there's a diagram of this somewhere on the web : Sheldon or somewhere

If your rims are 20mm, I thus wouldn't fit 19mm tubs, but 22-25's will probably be fine