Wednesday 20 August 2008

gluing cross tubulars

Opinions on gluing cross tubs are as numerous as conspiracy theories for 9/11. I have had a few requests on how to do it, so thought it might be a timely point in the seasons preparation to put some thoughts down.

There is no hard and fast method that one has to use, though most of the accepted methods overlap in many areas. In the end it's best to use what works for you - if you have confidence in what you have done, it will save time on the course and avoid skin-threatening moments.

For a great insight from a Euro pro racer, Greg Raine, scroll down for post entitled Sticky Fingers

Stu Thornes' ( Belgian method – this is slightly more controversial as some people suggest that no Euro/Belgian mechanics are doing this. Either way it is fast and the tires seem to stay on very well (from personal experience)

My method is set out below and is adapted from Simon Burney’s book as well as advocated by Richard Niewhus who owns and makes Dugast:

1. Lightly sand new carbon rims/lightly sand and clean old rims

2. Put new tub on old tub rim , inflate and leave for a few days to stretch. DO NOT inflate above 50 psi or it may explode. I have heard horror stories about people using 90 psi and wondering why their new Dugasts went pop – they are not designed to run much over 50 psi!

3. 1 thinnish layer of glue on carbon rim (Vittoria or Continental) – leave overnight

4. 1 more thinnish layer of glue – leave overnight. Ideally do 1 more layer as well to be sure – leave at least 8 hours to dry as always.

5. Put 1 layer of glue on base tape allowing it to soak in as much as poss. When dry after an hour or so put back on old rim to keep stretched. Leave 8 hours again to cure.

6. When you have done all this (phew) then you are ready to assemble – 1 more layer (thickish) on rim followed straight away by final layer on base tape (no more than 2 as it stiffens the tape too much). Leave no more than 10 mins max and put tire on rim. Careful – check the tread direction on the back wheel as you do not want to take off again. Place valve in valve hole, and pull either side of tire outwards before settling on rim. Check valve is not twisted to side. Continue to pull tire on rim trying not to get glue all over you and all over side wall. If it has been stretched enough and taken off rim at last minute then this should not be too much of a struggle. I use feet without shoes to hook toes over bottom of rim whilst pulling tire on at the opposite side.

7.Now inflate to 40 psi or so and roll tire with weight across floor to help push tire onto rim. The edges are where the tire sticks, not so much the centre so always glue the edges well and pay them attention. Leave at least 24 hours before riding.

Done. It is not as bad as it sounds once you have done it a couple of times and got well organized. Time and patience are the key and I have not rolled tires that have been glued on with multiple layers over several days and with love and attention.

Reward yourself with a Duvel, Vedett, Chimay or similar Belgian brew. Always more fun with a Euro cross race playing on DVD in the background.

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