creeping tubs giving offset valves

half cog

Retro Guru
Hi
Put this in the tubular tyre section a while ago and there was a deafening silence.I have tried cement using the reccomended methods and also velox tape but all to no avail. We have some very steep hills around here and after a couple of rides the valves start to lean over. The tubs are creeping under steady but hard braking. Front is the worst as this is where your weight is on steep decents. Thing is a long time ago ( and i mean a long time) I did most of my club riding on tubs and I dont remember having any problems so has anyone else had this problem and if so could you please tell me how you fixed it. I can simply turn the front wheel round but you cant do that with the back so its off with the tub and re set it. Any info much appreciated.Thanks
Peter
 

Old Ned

Old School Grand Master
Are the valves threaded? If so a threaded 'lock nut' (not sure what to name it!) might hold the valve in place. I must admit I've not really experienced this to any great extent even given the large amount of tub riding I did in the past. I used to use Dunlop cement (and still have a tin which, last time I looked, was still useable). The ones I've fitted in more recent years have used tub tape or the Dunlop but the number of miles on tubs has been minimal.
 

half cog

Retro Guru
Re:

Hi
Was always told not to use a valve lock nut on tubs.If the tub comes off you have a better chance of riding it out if the tub is not partially locked to the rim. having said that I have never had a tub come off. To be honest I think it would either make no difference or cause the valve to pull out if there was no give. I just dont remember ever having this problem back in my early riding days and as I was born within sixteen miles from where I now live I rode these same hills back
then.I am in the yorkshire dales and at one point on one of my rides I have well over 200 yards of around 1 in4 to descend. More or less a straight line down to the valley floor.By the time I get back home I have wonky valves again.Tried riding with max pressure to grip the tub better but it makes little difference.Was hoping someone had had the same problem and sorted it.Tub cement fares no better than tape. Suppose I could try a different make of tape.The tubs are new and those on now have only ever had tape on them. I bought new tubs to ensure that the old glue residue would not cause any issues. Would like to know what the mechanics on the tour use.Probably just change the wheels daily and reset the tyres. Thanks for the reply anyway. Tis appreciated
 

pigman

Senior Retro Guru
Re:

It's a long time ago, but my experience was

Dunlop glue is always tacky and the tub will move. The upside to this is, if you puncture, it's easier to remove the tyre and a spare tub pasted with dunlop will stick

Clement glue dries rock hard and the tub won't move, but is best reserved for race wheels where roadside punctures don't need resolving

Tape is great in that you don't have to brush it on and give it time to cure, but I somehow always found awfully messy when fitting new tight tyres
 

RobLoasby

Dirt Disciple
Always used shellac and never had an issue.

Mind you, it is nearly fifty years since I last changed a tubular. :D
 

pigman

Senior Retro Guru
Re:

Wasn't shellac used for dedicated track or crit wheels? I've heard of it, but never used it.

Probably 35 years for me since I rode tubs
 

half cog

Retro Guru
Re:

Not heard of shellack being used.Tape is the prefered method.Found a very easy way of fitting with it. The only cure I can think of is to set the tube with a slightly wonky valve so the breaking forces will pull it straight. As said the front wheel is no problem as I can reverse it. I have not pulled a valve out yet but cant help but think its only a matter of time. Thanks you for all the comments.
peter
 

mattr

Old School Grand Master
I used the conti stuff, couple of layers on the rim, couple on the tub. They've not budged in 1000km. Including some lumpy bits, and some rapid decelerations! (and i'm quite weighty, so a lot of force involved.)
 

pigman

Senior Retro Guru
Re:

I wouldn't have thought the back wheel valve would move. On the one hand, braking would move it forward, on the other hand the riders pedalling force countering against the tyre gripping the road would move it backwards
 

Old Ned

Old School Grand Master
Shellac was (is?) used on the track. To do it properly is a very time consuming process involving several (many!) coats, all left to dry between applications. Removing a properly fitted shellacked tubular should not be easy. Bikes were always checked before track meetings (as were road bikes before road races) and the security of tubular fitting was of paramount importance. I've known bikes using Dunlop or similar on their tubulars to be rejected. Saying that, I used Dunlop on my track wheels all the time and didn't have a problem. What do the current track bikes use?

When I was a lad, before I really knew much about tubulars, I read an article in (late 50's) 'Cycling' by Reg Harris on how to fit tubulars for track use with shellac. This included details of how to make up the solution using shellac flakes and methylated spirit, finishing in a relatively thick consistency. The stuff sold as wood sealant etc. is far to thin. TBH, at the time it put me off using tubulars but when I knew a bit more, the use of Dunlop cement for road use was revealed which stripped away a whole layer of misapprehension.
 
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