drewfio

I bought a new Panaracer Pasela tire, and I've tried a few times to inflate it, but it keeps coming off the rim when inflated up to pressure.

This tire says max 95 psi, and the tire starts to comes off at around 75psi. It doesn't happen immediately, but slowly after a minute or two. I had another Pasela on here previously that seated and inflated fine. When I compare the beads of the two they look different in a number of ways, but most notably it looks like there is less of lip/hook. There is also some wonkiness here and there in the overall shape (though this smooths out when I start to inflate. There are also little rubber ridges on the bead on the problematic tire. The other difference is that the problem free one is 27" x 1 1/8" and the new one is 27" x 1 1/4". 14mm inner width rim. I've put fatter tires on skinner rims without this happening, so I don't think that is the cause.

I've attached pictures of the two tires side by side. Left tire in the photo seats fine, and has been ridden no problem. Right keeps blowing off the rim. Is this a tire defect and causing my issue?

Thanks for the help!

Troul 

what are the specs of the tube that you are using? Is the tape/strip interfering with the tire bead?

drewfio

It is a continental race 28 25-32. It also says 27 x 1 1/4 on the box. I don't think the strip is interfering.

I just gave it another shot actually. I've changed many many tires, but I went through it again more slowly and carefully. So far it's been about 10 minutes at 80 psi and still standing. Fingers crossed.

If this holds, maybe I'll chalk it up to rim/tube/tire combo. The tire is not super snug on this rim and slipped on fairly easily, and the tubes are quite snug to the rim since even though it says 27 they are meant for 700 (do they make 27" specific tubes anymore?). So perhaps this combo made it so the tube could more easily creep under the bead during installation if not crazy careful.

I'll post back if it does/does not survive a while.

Crankycrank

Are the ISO sizes the same? Should have a 630mm x 32-33mm for the 27 x 1 1/4" tire. 630mm being the bead to bead diameter.

Andrew R Stewart 

What rim are you mounting these on? Is it a hook edge one?

Tires generally have a smaller range of fit diameter then rims do, or rims tend to have greater tolerances of actual bead seat diameter. But stuff does happen during making any high volume product so it could be the tire has an out of tolerance bead. Have you tried this tire on a different rim? Andy

drewfio

They are hooked, not straight. Though looking more closely, the hook is not as pronounced I think as on some other wheels I have. Maybe this is contributing as well. I don’t have another 27 inch wheel to try it on though.

drewfio

Yep it is vintage—a 1985 Nishiki Prestige. I don't know what you consider lower level, but it does have Tange Infinity tubing, so I wouldn't quite consider it junk. I've attached some photos of the inside of the rim so you can evaluate the presence/absence of a hook. The wheels are Araya rims with Sansin hubs. Also added a couple photos of the bike and wheels with the 27" x 1 1/4" tires now mounted, at 80 psi.

I measured and these are actually about 29mm wide on these rims. Probably pushing it for 14mm inner width rim. What psi would you suggest in this case? I typically run 25mm tires at 95 psi, and 32mm at 65-70, so I figured since this measure up in between those, I'd go with a pressure in between as well.

Test will be riding it I guess. Even if it stays on fine, it might not handle optimally. I've tried running some 28mm (actual) tires in the past on 13mm IW rims, and that did not feel great.

Thanks for the reply!

Iride01 

Are you positive those are 630 BSD rims? With the brake shoes bottomed out for max extension on the calipers it makes me wonder if those are 622 BSD.

drewfio

it says 27 x 1 on the Araya sticker on the rim, and the very old tires that were On there when I got it were 27”.

The pads are bottomed out because I had another set of wheels, 700c, in the bike while I waited for tires. And I wanted to swap back because those wheels are more expensive and in perfect condition, and I was planning to lock this up outside when I go places, and worried about theft. I just now put these back in, so I do need to readjust the pads higher for the 27” wheels before I ride.

SurferRosa

Great pics. Thanks. I wish everyone would do that. It would make this forum run so much more efficiently.

As I said, required road tire inflation is a function of total weight and tire width. I would find an online calculator that you trust and go with those results.

But I would guess, at 80 psi for those tires, you're maybe 180 lbs?

Iride01 

Of course you do. They need to be centered on the braking surface of the rim and not overlapping the edge where they might rub or eventually rub on the tire.

I guess that wasn't a question, but more of a statement. But that how we roll here.... we imagine all sorts of things one might say. <grin>

zandoval 

I buy mostly economical tries so finding defects is more common now days. Note also that I had to return some higher dollar Passelas because of defects too. So... When we get new tires ya just gotta give um a close, very close, inspection.

https://www.bikeforums.net/bicycle-m...l#post22308649

Troul 

they might prefer crispy tacos over a soft shell.

ThermionicScott 

Those look like Araya 20A rims to me. I've never had problems with tires blowing off of them. Make sure that you put a little air in the tube before installing it, ensure that the tube isn't trapped between the tire bead and rim at any point around the circumference of the wheel, and check to see if the lines molded into the tire are higher or lower at any spots as you're bringing the tire up to full pressure. If there is a low spot or a high spot, you can press it up or down with your thumbs, provided you haven't put too much air into the tube yet.

drewfio

Yep, those are the rims. I just took it for a test ride today, after more carefully installing yesterday, and all seemed fine. It rode pretty nicely.