Bumpy Tubs

I have never owned a set of tubs in 30+ years of cycling. My son had a planet-x track bike for Christmas/birthday and the only option on the build was tubs.

The bike was delivered early December and I noticed that there was a very large sideways wobble in the front and back tub. Planet-x customer service were helpful and I sent them back for them to have a look at. They agreed that they had been poorly fitted and refitted them. They called me to say they were much better but there is still a small bump where the valve is, they said this is normal for tubs.

We have just set the bike up after the Christmas chaos and stuck it on the rollers. The bump is quite noticeable when riding the rollers (I imagine it will be the same on the track).

Is this normal for tubs? They are Vittoria pista cs tubs.

I once misplaced a tyre lever inside the tyre. It was quite bumpy.
Can't imagine anyone doing that with a tub though.

Is this normal for tubs? They are Vittoria pista cs tubs.

Quite common with shit quality tubs and very common with tubs glued by people that don't know what they are doing or can't be arsed.

Don't think I've ever seen a PX bike with Vittoria tubs where they were glued on the correct way around.

Don't think I've ever seen a PX bike with Vittoria tubs where they were glued on the correct way around.

Sticking them on with the metal pointy bit facing out?

1 Attachment

Vittoria tubs carry their branding on the shoulder on one side of the tyre.

The branding is more slippy than the rest of the tyre so the tub should be glued so as to put this on the non drive side of the bike as it won't be in contact with the track while riding slowly if it is on this side.

More of an issue on single sided rear wheels than front or flip flop rears but even then, anyone with the slightest pride in their work would glue the tub so that when the wheel is fitted with the hub logo logo in the correct orientation the tyre logo is on the nds.

Aaaaah, this rings a bell. Timely reminder as I've just ordered a pair for track.

@eskay I had the same problem with my Pista Cs tubs, the bulge around the valve just didn't fit my rims.
@M_V is right, they need to be glued with the logo on the nds, otherwise they are dangerously slippery on indoor tracks.
At the end I went for Continental Sprinter, a lot grippier and the bump disappeared.

Glue your own or in this case your son's tubs on to rims. Nobody else will do it as well as you. I use Vittoria Mastik.

This is what I do. Clean excess adhesive from rim focusing on lumps, same if re-using tubs. 3 thin coats 12hrs apart, or until very touch dry (not tacky touch dry). 1 coat on tub on 3rd coat of rim. Then a fourth coat on rim, leave for 20 minutes and then fit tub.

My tip is to start in a differnt place with each coat, as there is a tendency at the start to apply too much adhesive and if this is around the valve then you will get a bump.

This is the video for gluing tubs on aluminium rims by Continental. There was one for carbon rims which is basically the same.

https://www.youtube.com/watch?v=2DLSG2WT0mc

Thanks for all of the comments.

@M_V - I have just checked and not sure if by intention or a fluke but the branding is on the non-drive side.

@colinsmith123 - Thanks for the info and video. He wants to ride it tomorrow night so will leave the tubs for now and then probably have a go at refitting them. I have done a bit more reading online and some people suggest opening up the valve hole slightly with a countersinking tool to help alleviate the problem...?

I drilled my aluminium rims out slightly so that the valve seated properly with my CS tubs.

Bumps are not "normal" on tubulars if they've been properly fitted, and you should be able to reattach them better than this. Best advice I was ever given involves the use of an old broom handle - or big bit of dowel. Run the wheel, with tyre freshly attached and partially inflated, up and down the broom handle until everything is firmly seated and even. Then pump the buggers up as hard as you can and cross your fingers.

I have had a running battle with these tubs since the original posts but PX agreed to send me some replacements (base tape became unstuck after they refitted them, the front tub started to slide to one side from riding around the track in one direction etc etc).

The tubs got lost in the post so the glue (3 layers) I put on the rim has been on there for about 3 weeks. Will it still be OK to stick the tubs on now, or should I remove the glue from the rims and start again?

It should be fine, when you get the tubs glued up and on the rim, the pressure from the tyre being pumped up with re-activate the glue on the rim

Untimely reminder for me, as I just glued a new set on last week. I could just re fit the rear and turn the front wheel around...

And I always thought it was bad slow pedalling technique that made me slip at the top of the banking.

I can't get my tubs to sit flat on my px wheels. I noticed they're not completely round anyhow but still a little proud at the valve.

Not too sure if widening valve hole on carbon is good idea, just as unsure about trying to trim off tape.

Not massively out or too noticeable but would like the best fit before committing with glue. Any suggestions beyond riding on a broomstick?

Thanks

omg! I had this problem aswell, using a PX 82mm. It would have one slight bump, even though I was experienced at putting on tubulars...On my zipp, hed, ambrosio and other tubular wheels, they would sit perfectly, so I ended up selling the wheel, as I knew there wasn't much wrong with my technique and I don't want the LBS to charge me £30 and have it there for like 3 days. If you can see the bump clearly, chances are you will feel it, and it will be more than annoying. Check you have the same amount of the fabric tape (underside of the Tub) barely showing but equal on both sides of the rim.

Thanks James, I have 82mm also. I originally got Vittoria Pista which are quite thick and come folded which leaves a slight bump even after pre-stretching). Glued them on with tubasti that I find to be like toothpaste(first time gluing). I did think maybe the glue was thicker in one area but I did a decent job and it shouldn't stick out that much.

When I got a flat in the back tyre I replaced it with a Pista Evo CS which is a lot thinner (no more riding outside) and comes loosely wrapped (no folding bumps). I used Vittoria Mastik One which goes on nice and thin.

fabric tape sits equal all the way around and there is no side play in the fit, there is more tape showing around the valve though as it sits a little higher. the ridge on the seam at the base of the tyre doesn't help, but I guess it must be down to the valve hole, can't remember what this looked like on my old tubular wheels.

I still got the bump as before but a lot less pronounced, as I'm now replacing the front I was hoping there might be a trick to getting it smoother tyre.

had no issues with previous road tyre tubulars (Tufo + tape), I don't notice it all that much on the track but on the rollers it is noticeable.

Have PX 82mm too and had the same problem with Vittoria Pista Evo CS tubs. It was a while ago now but think the problem was with the shape of the valve and the hole...had chat with LBS and ended up shaving a chamfer into the hole so the valve would sit flush. Warranty couldn't be more invalidated but wheels and tubs were unusable otherwise.

Thanks Seanos, I ended up going down that route. Started testing with a round file and worked down until flush. Still not getting the perfect round tyre but close enough.

I had the same issue with Conti Sprinters on my chinese 88mm rims.
First application gave some really poor results but I put that down to my technique as I didn't "stretch" the tubs into the rim as I worked away from the valve.
Did this upon re-application, tubs sat better but still a little lumpy at the valve.
I then opened up the valve hole with a small round file and chamfered it out a little too.
Third re-application and they're pretty good although the construction of the Sprinters means they have an overlap of the base canvas which is impossible to get rid of.
I think I'll ride these for a bit and eventually get some higher end tubs.

Just to add to most of the comments above, I used a countersink tool to open out the valve hole and add a chamfer. They sat better when I glued them on and he has been riding them for quite a while now with no further issues.