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I just installed two new Conti GP5000s on my Specialized Allez 700c 26mm aluminum wheels, using the original tubes. (Bike was purchased new 4 months ago). So I pumped up one of the tires and spun the wheel while holding axles in my hands and noticed unevenness in the height of the tire, depending on rim location. The tire seems even on center, but has variation in the height. This would definitely be felt while riding, since the height of the axle would oscillate - i.e., bumpy ride.

Attached are some pics in which you can see (with maybe 30 psi) the cross-hatching on the outside of the bead, while on the other side the cross-hatch is not visible.

Is there some sort of massaging that has to be done before inflating to prevent this variation in height?

UPDATE

Today I deflated both tires, massaged beads away from rims, brushed on soapy water, applied 100 psi via compressor, and the tires popped out fully - "like butter". Took for test ride, no issues. They seem lighter than the stock OEM dogmeat tires, which are listed as 26mm -- these GP5000s are listed as 700x25 on the box. Used digital micrometer and the width at 100 psi was 26.2mm, whereas the stock OEM tires were 27.5mm at 100 psi. To me, that's a lot of rubber difference, i.e., weight delta. Overall, the rotational momentum needed to accelerate seemed much lower than the OEM tires - exactly why I installed GP5000s.

UPDATE 2

Went for long ride today, and OMG!, these Conti GP5000s provide a much smoother ride than the OEM tires, even at 100 psi. They're lighter and require less energy to spin (rotational momentum) which can be felt during pedaling. Since I also upgraded from the OEM flat pedals and wearing sneakers to Shimano Ultegra (one-sided clipless) pedals, black-yellow Shimano cleats with float, and Fizik Overcurve R4 cleated shoes, the energy efficiency is much higher. Next upgrade will be to Mercury S5 carbon-fiber wheelset, then possibly a hollow Shimano Dura-Ace crankset.

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    If you can't get the bead to seat in, release all the air and put a little bit of soapy water on the bead. Regardless it will probably take alot more than 30 PSI to get a road tire bead to seat into the rim.
    – Squashman
    Feb 18, 2022 at 1:45
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    "This would definitely be felt while riding" - definitely a 'not necessarily', as the tires stretch as weight is applied, they aren't rock solid. It's common for tires to have a few mm wobble when in the truing stand but roll just fine.
    – whatsisname
    Feb 18, 2022 at 2:35
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    The box for my new set says 120 psi. I usually run 100. My son who weighs light as a feather runs 80 on his TL's.
    – Squashman
    Feb 18, 2022 at 2:58
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    Your pressure will also depend on their width. I have 35mm wide gp5000tls I run at about 70 psi
    – whatsisname
    Feb 18, 2022 at 4:42
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    Comment about update 2: Upgrading an entry level bike with usually top-notch components isn't worth it. First entry level components are not always compatible with high-end ones, so choose wisely what can be reused. For example: you said in another post that the bike has a 2x8 groupset. A Dura-Ace crank will require you to replace the whole drivetrain (8-speed vs 11-speed) and the brakes (mechanical rim brakes vs hydraulic disc brakes) — brakes and transmissions are "linked" because of the brifters. For that kind of stretch, better to keep the money and buy a whole bike instead.
    – Renaud
    Feb 20, 2022 at 7:56

3 Answers 3

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Its just a common problem when installing a new tyre out of the box.

GP5000 are folding tyres, which are slightly harder to get into position when new. After they've been on the bike for a while you can get them on easier because the tyre will take a "set"

To fix this, deflate the tube to flat, and manipulate that spot on the tyre with your hands. Push the sidewall in with your thumbs and adjust where it lies. Ideally you want some line on the tyre's sidewall to be the same height off the rim, all the way around the wheel.

It is possible to add some slightly soapy water to the bead and then inflate the tyre. The bead should POP into place and scare you whitless at the same time. If ~100 PSI doesn't do it, then give up and go back to manually locating the tyre as above.

All this presumes your rims are round and true.

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    Thanks - like I said in the comment above the rear wheel has the cross-hatching visible all the way around and its tire height seems even. The front however, where the cross-hatching is not visible (pic), as you suggest, probably hasn't popped out under higher psi. I only pumped maybe 20 psi by hand. Will deflate, hand massage a little, use soapy water and compressor tomorrow with 100 psi. Wheels were trued during tune up in November.
    – user0123456789
    Feb 18, 2022 at 2:51
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    @user0123456789: Regarding true-ness: To check for true-ness you should focus on the rim sidewalls anyway, not on the tyre.
    – Michael
    Feb 18, 2022 at 8:01
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    @Michael yes - my point was that some mark on the tyre is being visually compared to the rim, as a datum. If the rim is out of true or shows lateral run-out, the tyre might look more-wrong. Its pretty unlikely, but not impossible.
    – Criggie ♦
    Feb 18, 2022 at 10:15
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Usually inflating them to maximum pressure or slightly higher is enough to seat them. They’ll move into position with a loud “pop” noise.

But first make sure the tyre is installed correctly and not pinching the tube anywhere. You can also try to seat the tyre manually at very low pressures.

I’ve never had to use soap water or anything, and I change tyres a lot.

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There's also the possibility the inner tube has folded over itself inside the tire. This can happen of the tire moves on the rim as you're seating it. The tube can't move because the valve stem holds it in place. If the tire does move, it can drag parts of the tube with it, stretching the tube on one side and folding it on the other.

That can cause an uneven tire when the tube is inflated, too. The only way to check is to let the air out, unseat the bead on one side, and look inside.

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