IwanaBrich

Mt wife's Trek 720 Hybrid bike needed new tires so I decided to by her a tad wider tire than was on bike. It had 700c-35mm tires and I purchased Venture Road TCS tires 700c-40mm. I also changed the tubes and used 700c tubes that fit tires from 35mm to 42mm tires. There is plenty of room for the wider tires, so no issue there, First these are the first folded tires that I've ever put on bike. They went on the rims fairly easy, but I can't seem to be able to get them to seat evenly all around the rim. I put one side of the tire on rim. I then put a bit of air in the tube, so it was slightly inflated, then fit it inside the tire and then put the remaining side of tire on the rim. I initially only put like 10 lbs in the tire and adjusted the tire so it seem like it was evenly installed. Then I put in a tad more air, I spun the tire and watched for high and low spots and tried to adjust accordingly by manipulating the tire. Well everything looks fine, until I get 40 lbs in the tire when high and low spots appear. One time, I thought it was perfect, so my wife took it for a ride and by the time she made it around the block it was all uneven again! It's as if the tire is moving on the rim. Is this normal?

What am I doing wrong??? Could the tires be defective?? Are they too wide for the 700C rims?

I'm ready to scream! Please help!!

Andrew R Stewart 

First thing I think of is having the tube trapped under the tire's bead. Not an uncommon issue, especially when a tire is flopping about during the install (as a folding tire can want to do).

When the tire is properly mounted the molded rib that is just outside/above the rim's edge should be an even height off the rim. Is this so? If the rib is inside the rim then you end up with a low spot. If the rib raises up off the rim more in one spot then the rest then you have a high spot. The amount the rib is above the rim edge speaks to how much tire is overlapping with the rim.

Having said all that telling you what's wrong is a crapshoot long distance. Any chance you can show the wheel/tire to a shop? Maybe the place you bought the tire from? Andy

dsbrantjr

Try lubing the rim/bead with some soap/detergent and water. Also make certain that the valve base is not caught between the bead and rim. Before fully inflating the tube push the valve down into the tire and then pull it out firmly so the base seats against the rim.

trailangel

Everything everyone else has said... plus more air. How about inflating to the max it says on the tire?

Troul 

if nothing is being pinched, inflate the tire to the point you once had a time, you thought it was perfect. Take the wheel assembly & place it firmly on the ground while simultaneously caressing with finesse of the sidewalls. Your essentially massaging the bead evenly in to place. Once complete, air the tube up, achieving no higher than 10% under MAX psi of the tires max limit.

Badger6

OP, in my experience with lots of different tires, when inflating (tubes or tubeless), to get the tire to seat evenly (Andy has well described the easiest way to visually confirm this), I always inflate until I hear a series of pops/pings which usually means at or just beyond the max pressure. Do a visual check, and if the tire is seated, set the pressure to the desired point and go ride!

Moe Zhoost

I've had this struggle before, but eventually was always able to get the tire seated. Inflating gradually is always a good idea and can work if you check and manipulate the tire as you progress, but sometimes that does not work.

Tube interference is a real possibility, though it should rarely be an issue for a person with experience. I have had it happen when the tube is on the bulky side, though. I'd recommend that you reinstall the original narrower tube to see if that resolves the issue. If it does resolve it, you then have the choice of trying to use the wider tube installing it with increased care or sticking with the original. Running the narrower tube should not be a significant issue.

Some have had success over inflating the tire to force it to seat. It doesn't sound like you can get that far, though.

Also: Are you having this issue on both rims or have you only done one?

Iride01 

Go by the witness line just above the tire bead. What you are seeing might be more just tread patterns and other markings on the sidewall of the tire that really don't affect how it feels while riding.

But I have had some tires that were impossible for me to seat correctly. I got rid of that bike.

IwanaBrich

Badger6 I took your advice and broke out the compressor (I was using a hand pump up until then). I set the max pressure at 60 lbs on the compressor and started pumping up the tires and sure enough I started to hear the popping sounds of the bead seating into the lip of the rim. This worked for the rear tire right away, but not the front. The front was a tad more stubborn. I marked with tape where the low spot was, so I wouldn't forget it. Then I deflated the tire quite a bit and I tried to pull the bead out in the low spot by hand, but it didn't seem to budge. Then I upped the max pressure on the compressor top 70 and re-inflated the tire. Well before I hit max pressure, I heard the "pop" and everything looked fine! I've changed lots of bike tires in my day, but this is first time that I needed to use a compressor. I was always afraid of accidently over inflating the tire.

Thanks for all of your support!

Badger6

Awesome!!! You can do the same with a track pump...it's just slower and you're gonna have to work the handle up and down. Regardless, you're set now and you're a little more versatile on the wrenches.