Unround tyres - advice please.

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All uphill

Still rolling along
Location
Somerset
I have a pair of Schwalbe G One folding tyres that I used a couple of winters ago on my Spa. They were great.

I now want to fit them to my Marin which has Ryde Zac 19 rims. They go on easily - no levers needed, but I can't get them to inflate to a nice circular shape. There are no kinks or damage that I can see.

I've over-inflated, under-inflated, manipulated, put soapy water on the rims but they just will not sit in a position that gives a round wheel.

Could this just be a very poor rim/tyre match or is something else happening here?
 

ianrauk

Tattooed Beat Messiah
Location
Rides Ti2
Can you take a pic?
 

wafter

I like steel bikes and I cannot lie..
Location
Oxford
Have you made the common error of confusing your tyres for eggs?

If the beads aren't sitting consistently on the rims I've found applying a decent synthetic grease to the contact areas and perhaps over-inflating a bit to help.. although this comes with the caveat that some have experienced tyres slipping on their rims under certain circumstances and grease likely wouldn't help in this regard... although I've never had problems.

Also, you're probably well aware but if there's a lump at the valve, deflate, push the valve as far into the rim / tyre as it'll go and re-seat the beads in that area.

If they're sitting properly on the rims but are just on the wonk otherwise, a bit of heat and use would probably help.
 
OP
OP
All uphill

All uphill

Still rolling along
Location
Somerset
Can you take a pic?

I'll do that, but I think I may have the answer.

Marathon + tyres fitted easily on these rims, so I think it's safe to assume the rims are marginally under-sized in diameter. The G-Ones are used and floppy.

The tyres don't wobble side to side, just vertically. Taking them on and off shows that the high and low points are not at the same position on the rim or tyre.

I'm pretty sure this is a case of slightly over size tyres on slightly undersized rims.
 
OP
OP
All uphill

All uphill

Still rolling along
Location
Somerset
Have you made the common error of confusing your tyres for eggs?

If the beads aren't sitting consistently on the rims I've found applying a decent synthetic grease to the contact areas and perhaps over-inflating a bit to help.. although this comes with the caveat that some have experienced tyres slipping on their rims under certain circumstances and grease likely wouldn't help in this regard... although I've never had problems.

Also, you're probably well aware but if there's a lump at the valve, deflate, push the valve as far into the rim / tyre as it'll go and re-seat the beads in that area.

If they're sitting properly on the rims but are just on the wonk otherwise, a bit of heat and use would probably help.

Good idea about using synthetic grease. I'll give it a go. At low pressure (1.5 bar) the tyres will move on the rims.
 
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