Tubs - do they really roll off rims?

bahzob

I've just got myself a tubular wheel + tyre. I've avoided these in past, partly because of stories that in extremis tyre can roll off rim.

However, given the amount of effort needed to get the it in place I find it hard to believe that a fully inflated tub tyre will come off rim. Maybe it will if punctured beforehand but then so will clincher.

Has anybody actually had a situation where a tub has come off wheel?

(Aware Beloki crash is often cited as example but looking at video + later discussion jury seems still to be out in terms of what triggered fall)

Smokin Joe

Once crashed in a road race when the guy inside me on a corner rolled his front tub and took me out. It does happen, but not that often IME. No matter how tight a fit the tub is on the rim if it isn't stuck down properly it will roll.

APIII

The last time I punctured a tub it took me about an hour to get the bloody thing off, so if they are well glued then I would expect them to be harder to roll off the rim than a clincher if you flat. A lot of people use tape. Not tried it myself yet, but I guess it has the advantage of 100% coverage of adhesive. You can always miss a bit when using glue.

pedalrog

A tub shouldn't roll off the rim if it's stuck on properly. I have seen them come off, marshalling a road race some years ago, a chap - no. 13 would you believe, rolled his tub on the corner I was standing at. I picked up his bike and the glue was still wet - a clear indicator he had only stuck it on that morning, somehow had escaped the bike examiner at the start. Served him right really but he could have brought others down.
It's never happened to me but then I am very cautious when using them, glue it on at least 24 hours before use or use tub tape which is instant. Make sure the tyre is seated properly, test it by trying to roll it off with your hand.

Alex_Simmons/RST

No properly glued tub will roll off the rim.

However tubs not properly glued can and do. Ask Neil Stephens - it cost him a stage win the the TdF.

Under no circumstance put a tub on without properly gluing it.

Pokerface

Use glue and lots of it to be safe. When I worked at British Cycling they used EIGHT layers of glue (applied once a day in thin layers) on their tubular rims. They never, ever, ever, ever would use the tape.

Now - these were mostly for TRACK wheels - where you are constantly cornering - but the same principles apply to the road ones.

If glued on correctly - it should not come off.


Take the time to glue them on right the first time. (I used eight layers when I did my own).

You don't have to use the full eight layers if you puncture and put a new one on.


Good thread elsewhere that discusses how to glue them on: http://weightweenies.starbike.com/forum ... hp?t=56813

Monty Dog

I'd much rather have a front wheel blow-out on a tub than a clincher - there is a slim chance with a tub you have some rubber between the wheel and the road, whereas with a clincher its metal/carbon on tarmac and looking forward to big dentistry bills. This is one of the reasons that most of the pro peloton still rides on tubs - regardless of what the tyre makers tell you.

bahzob

Thanks for replies so far.

It feels like there is some evidence that tubs can roll off in extremis, however it also feels like the examples come from quite a few years ago.

Wheel design/manufacture has come a long way since then, anybody had a recent example? Specifically anybody had a tyre roll off a carbon rim (which is what I will be using)?

Also, since planning to use tape not glue (seems a lot more straightforward), any objective evidence that glue is safer?

Dess1e

Again properly applied tape is ok, if you need reassurance you could use Tufo Extreme tape, but be careful what brand of Carbon rim you are using as there are tales of it peeling off a layer of carbon when being removed.

The main scenario that is likely for glue / tape to fail is on a long alpine type descent, with a lot of braking, causing the adhesive to "melt" thus allowing th etyre to squirm around / roll.

blorg

Monty Dog wrote:

I'd much rather have a front wheel blow-out on a tub than a clincher - there is a slim chance with a tub you have some rubber between the wheel and the road, whereas with a clincher its metal/carbon on tarmac and looking forward to big dentistry bills. This is one of the reasons that most of the pro peloton still rides on tubs - regardless of what the tyre makers tell you.

I have had two front blowouts on clinchers, one on a fast solo descent and the second in a bunch during a race, and controlled the bike to a safe stop both times. I've seen others do the same. It is a risk but crashing is not inevitable. I wouldn't have fancied my chances cornering mind.

I have seen a tub roll off first hand, cornering in a crit. Probably wasn't glued right, but I just don't know that I would trust myself. (Rider was fine BTW.)

dennisn

Here in the States race officials are req'd. to do a sort of hands on inspection of any wheels using tubulars. Every once in while we will find someone who has decided that
not using proper amounts of glue or incorrect gluing are problems for other people and not him. As officials we can, and will, pull him from the race.