Tyre seating woes

thistle_

Got back from a ride last week and noticed a split across my tyre. Went to the LBS the next day and got a new one (Giant SR4 - all they had!)

I swapped it over and it seemed OK going down the garden at home.
The next day I went for a ride on some smooth tarmac and bump bump bump something's not right. I tried sorting it at the weekend, and I've had another go this evening but still can't get it right.
So far I've checked/tried the following:

• Held an allen key against the brake just above the top of the rim - the rim doesn't move up and down so seems circular
• Held an allen key across the brake - the bump is at the valve location/tyre logo
• Turned tyre around 90 degrees - bump just before the valve location
• The seam above the wire bead seems to be the same distance from the rim all round
• Pumped up to 50 psi - bump still there just before the valve
• Washing up liquid all around the rim and pumped up to 140 psi - no change
• Deflated, rolled wheel around on the floor and pumped back up - no change
• Deflated, pressed valve into tyre while inflating - no change
• I have cheap plastic rim tape which came with the wheels that's welded at the valve hole. I cut about 3mm off each side of the tape at the weld in case the weld was stopping the tyre bead seating low enough - no change

I'm at a loss now.
Unfortunately I don't have the old tyre to put back on and see if that one seats correctly.

Any ideas on anything else to try before I bin the trye and try a different one?

ridgerider

Deflated, pressed valve into tyre while inflating - no change

This has happened to me before, but the above action always remedies it in conjunction with pushing the tyre down into the rim once the base of the valve is out of the way.

lesfirth

I had the similar problem with a pair of Giant tyres. I do not remember the type but they were front/rear specific and very cheap. We do not have many smooth roads around here so it took me a while to realise that I was bobbing up and down. On investigation I found both tyres had about 5mm variation in height. I went through a similar steps trying to overcome the problem without success. I gave them to a mate.

thistle_

lesfirth wrote:

I had the similar problem with a pair of Giant tyres. I do not remember the type but they were front/rear specific and very cheap. We do not have many smooth roads around here so it took me a while to realise that I was bobbing up and down. On investigation I found both tyres had about 5mm variation in height. I went through a similar steps trying to overcome the problem without success. I gave them to a mate.

Sounds like a plan.
They are "cheap" tyres, although at £20 not that cheap.