Cycling UK Forum

Hi there ,

I purchased and fitted two new tyres to my bike , WTB Byway 44mm, on 19mm internal width rims replacing some awful Chen Shin Tyres 35mm.

The Tyre I fitted to the front seems to have quiet a substantial wobble or deformity. I'm not really sure. It bobs up an down a good 5/6mm I reckon.

In the video you can see that its not a wheel issue as the brake track does not follow the irregularity of the tyre.

I swapped the tyres around to be sure its not the wheel or tube but the other Tyre was fine.

I have purchased Tyres in the past that were a little off round or popped out a bit but I never found it effected the actual riding of the bike. However here I am really Squeezing these larger Tyres into the frame so I'm of half a mind to try get this Tyre exchanged or refunded. Does this look like an unacceptable amount of Tyre deformity or out of roundness?

https://youtu.be/I0hWn9BVO6M

Not that much!

You've already removed and refitted it.

Can you detect the problem when you look at and feel the tyre off the bike?

Did it arrive folded?

Thanks

Jonathan

PS: One of the many excellent features of this site is that you can embed YouTube videos inline:

It's possible that the tyre has not seated perfectly. Sometimes if you increase the pressure by inflating beyond the max pressure rating you can get it to pop into place. Where the tyre is obviously low can you push/roll the tyre with your thumbs to check if the bead is seated fully or still in the well of the rim.
Lubricating the tyre bead with soap also helps it to seat fully.

Sometimes I've found the need to 'massage' the tyre to get a better fit - you may have already done this, or inflate it to its maximum pressure. I'd say about 3mm is acceptable.

Interesting post.

I have a similar issue with a pair of 32mm WTB Crosswolf tyres on my cyclocross bike. Can’t get them to sit “round” on the rims. The rims are laterally true and round when assessed on my wheel stand. My 28mm Vredestein and Vittoria tyres seem to sit ok on them, but maybe the effect is attenuated with smaller sized tyres? I’ve come to the conclusion that there must be an intrinsic defect in their construction/shape.

I not sure if it’s just conscious bias when I ride the bike with the WTBs but I think that there is a “bumpy feeling” ride with them when on road.

Thats a tyre seating issue. Look at the later bit of video, taken from the side; you can see the tan tyre wall going up and down relative to the rim.
As already said, try inflating the tyre to the max pressure on the sidewall, and bounce the wheel like a ball....this is sometimes enough to seat the tyre properly.
If that doesn't work, take the tyre off and check the rim tape is straight; if the rim tape is covering the bead seat somewhere it can mess up the tyre seating.
Last thing, lubricate the tyre bead with washing up liquid and do the max. pressure bouncing thing again!

Your front rim is likely to be significantly bigger than the rear one, so that either tyre seats properly on the rear, but both tyres are a pain to seat on the front.
edit...just read the first post properly.....it looks like the tyres are significantly different diameters, not the rims!

audaxjk wrote: ↑4 Jun 2022, 6:44pm I have a similar issue with a pair of 32mm WTB Crosswolf tyres on my cyclocross bike. Can’t get them to sit “round” on the rims. The rims are laterally true and round when assessed on my wheel stand. My 28mm Vredestein and Vittoria tyres seem to sit ok on them, but maybe the effect is attenuated with smaller sized tyres?

I have had the same experience with Kinesis Crosslight rims, i.e. 32mm WTB Crosswolf tyres and 40mm Vittoria Hyper Voyagers are difficult to get to seat properly round, but 28mm tyres are fine. It also happens to a much lesser extent with Kinlin XM-250 rims and 40mm Schwalbe Almotion tyres. I use all with standard inner tubes.

The Crosslight rims have a very pronounced shoulder between the central well and the (I think possibly somewhat narrow) bead seat, compared with the Kinlin XM-250 (profile below).

So far my thoughts and experience are that some of these combinations of wideish rims and wide tyres seem to work for me only if the tyres are nearer to their maximum recommended pressure, and the pronounced shoulder in the Crosslights seems to need excessive pressure to get the tyre to seat - I am intermittantly persevering, and I suspect I will need to determine what pressure to seat the tyre, and then to what pressure I can lower the tyre without it later slipping off the bead seat when riding.

It is not a significant issue to me with the Kinlin XM-250 rims, but it is with the Crosslights. Moreover the Crosslights are on a bike which I ride off-road, and on which I would like to be able to use low pressures.

I don't know whether problem would still exist with a tubeless set-up, and I suspect the main difference might be the effect of using tubeless tape 2mm-4mm wider that the internal rim width, with the result that tyres sit on the tape, which effectively slightly increases the bead seat diameter and results in a tighter tyre fit, and might keep the tyre bead in place at lower pressures. At some point I will get some tubeless tape and see if that does make a difference.

The OP's WTB Byways are rated for 25-50psi, and I would start by ensuring the tyre was close to 50psi.

slowster wrote: ↑4 Jun 2022, 7:35pm ........... I suspect I will need to determine what pressure to seat the tyre, and then to what pressure I can lower the tyre without it later slipping off the bead seat when riding...........

Do they slip off the bead seat at lower pressures? I haven't tried your examples (or very low pressures) but for me once the tyre is seated they have stayed seated.

Adding tubeless tape to the rim will increase the bead seat diameter and make the tyres harder to fit.....but you know that!

531colin wrote: ↑4 Jun 2022, 9:17pm Do they slip off the bead seat at lower pressures? I haven't tried your examples (or very low pressures) but for me once the tyre is seated they have stayed seated.

Yes they do slip off the bead seat at lower pressures. With the Kinlin XM-250/Almotion combination it is trivial and just prompts me to put a bit more air in the tyres. The Crosslight rims however seem to need to have the tyres pumped up to at least the maximum recommended tyre pressure, whereas I would like to run lower pressures, especially when off-road.

If a tyre slips off the bead seat I do not notice it when riding off road. It is only on relatively smooth tarmac, e.g. chip and seal, that the sensation of a 'bump' every wheel rotation is noticeable.

I've read of MTBers lowering their tyre pressures when they get to the trails etc., and presumably pumping the tyres back up when they get back on the road, but I would not want to do that on a touring bike.

Try inflating to fill the tyre and then pushing any high spots in?

Making sure it's properly round before going to full pressure??

It is hard to tell from the video, but tyres often fail to seat themselves evenly on the rim without a bit of manipulation. A common thing is when one part of the tyre sits too low and needs massaging up while the tyre is half inflated. Stubborn tyres can still refuse to rise up at the low point and need massaging while under higher pressure to get the bead to rise to the hook of the rim. I have occasionally over-inflated tyres to force the low spot to rise up, lowering the pressure to the right level afterwards.

Rarely you will get a bad tyre that is simply not of a uniform shape. There is nothing you can do with that.

I know this isn’t my post but thanks for your observations/advice all the same. My rims are in fact Kinesis Crosslights as Slowster correctly guessed.

I’ll try the checklist advised re: tape position pressure and soapy liquid and see how I get on.

Over the years, I have had a couple of duff tyres like this. One Specialized (an MTB tyre) and one Schwalbe (a road tyre). It happens.

slowster wrote: ↑4 Jun 2022, 10:08pm

531colin wrote: ↑4 Jun 2022, 9:17pm Do they slip off the bead seat at lower pressures? I haven't tried your examples (or very low pressures) but for me once the tyre is seated they have stayed seated.

Yes they do slip off the bead seat at lower pressures. With the Kinlin XM-250/Almotion combination it is trivial and just prompts me to put a bit more air in the tyres. The Crosslight rims however seem to need to have the tyres pumped up to at least the maximum recommended tyre pressure, whereas I would like to run lower pressures, especially when off-road.
.............

Thats really unhelpful, isn't it? And you have to buy and fit everything before you find out its a useless combination.
I would be trying to return the tyres, but I don't know where you stand legally....14 days for internet purchases? and I would argue that you can't know the stuff is unsuitable until you have ridden on them.

Thanks for replies I will try some of the ideas above to see if I can get it to fit better.

Question would having undersized tubes cause this ? I am currently running 35mm tubes in these ill fitting 44 tyres.