yannisg

Shimano RS700 wheels with Continental 5000 TL 700X25.
Wheetset and tires were new.
I mounted one tire on the rear wheel with a struggle, but in one effort.
I tried mounting the other tire on the front wheel, but after struggling hard, wearing light work gloves to increase the grip, I gave up after struggling for 15 min and with bruises on my palms.
Tire lip in the rim well, and pulling all the slack as much as possible.
I decided to leave the half mounted tire in the sun for about 3 hrs (26 Deg C).
Then I tried to remount the tire which I did successfully with a struggle, but one hard try. There was definitely a difference.
I suspect there was a slight difference in tire diameter.
Anyone use the EZ-Clincher Pocket Tire Tool

Drew Eckhardt 

1. Use two wraps of 1 mil Kapton (5/8" or 16mm for traditional rims, 3/4" or 19mm for wide) totaling 0.005" thick versus .010" for thin rim tapes and .020" for Velox.
2. Start the second bead across from the valve stem instead of starting there.

Together those two things make the difference between cussing at tools and comfortable hand mounting.

yannisg

I used the rim tape that came with the new wheels. So, you are suggesting I should have replaced the rim tape?
Second bead across from valve. Yes
I was surprised regarding the difference of mounting same tires on same rims.

Drew Eckhardt 

Yes. It makes a huge difference in how much slack you have.

davidad

Amazon.com : Kool Stop Bicycle Bike TIRE Bead Jack Lever Tool New : Sports & Outdoors

Chuckles1

Soapy water on bead of tire and rim can be a hand-saver. Careful with tire jack; you can bend your rim if you apply a lot of force.

70sSanO

This is interesting. On tough tires I’ve used the old VAR lever and now the tire Jack. I’ve never heard of a rim bending; not that it can’t happen.

The VAR lever would bend to where I thought the lever was going to break, but it never did.

John

adipe

i prefer to have a wide AND thick enough rim tape. one way i know the rim tape is not too thin is having just a bit less spoke tension after mounting the tire, inflating and then releasing air pressure (tire fully mounted on the rim).

one of the reasons why tires are hard to mount on the rim would be low average spoke tension. that's because there is rim compression (circumferential) due to spoke tension. sloppy built wheels will have too high tension variance and also low average spoke tension. very few people care to study the whole science - not art. it's hard to have someone explaining it to you and if you don't understand the science behind wheel building chances are that each time one person learns from another... either some things will be missing in the knowledge passed on or some error/superstition in that knowledge will be passed on.

other reason of tires being hard to mount... is not knowing the proper technique. or the rim not having a deep enough channel (shape). but again, this problem can be addressed with the proper technique.

https://i.stack.imgur.com/PMulr.png

yannisg

Don't disagree with yr comments on spoke tension and variance. However, these were new wheels. I always record the spoke tension and trueness of my new wheels.
However, my post was more about the difference I encountered regarding mounting similar tires on similar rims, and the effect of sun heat.

deacon mark

I use tubes so a tire if I could not mount very easy would not be an option. I do use Conti 5000's but not the tubeless version. Sometimes a tire is hard are first to get on but once pumped up and then remounted it gets easier. I assume since tubeless you are not planning on having to mount tire on the side of the road, but not sure. One option is to pump tire up to well over the maximum to say 140 psi and then take it off and remount again. If you do this about 3 times the tire will be much easier by far. They stretch and I have had tires I needed a level new to mount but later easy with the hand. I must admit I have rarely ever come across a tire I could not mount by hand.

davidad

The jack pushes down on the rim and won't bend it. The other way is on this video. I wouldn't like to do it in the rain. I tried a set of these and they lasted a long time, but were so hard to mount that I haven't bought another.

Chuckles1

First and only time I used a tire jack my rim bent. It was pretty well worn out from braking, wear dimples were long gone, so that was likely a factor.

davidad

I rarely need it for my usual tires ( panaracer Parcelas kevlar bead), but it is handy as my old hands don't have the strength they once did.
Anecdotally I haven't bent a rim with mine. I carry a VAR on the bike.