Thumpic

I have pinched and patched 3 tubes several times and I still cannot mount my 700C rear tire without ruining the tube. The bike is a 2002 Lemond Tourmalet. I see no marks on the rims about size. The front tire was difficult, but achieved. The rear tire however has beaten me. Bikepedia says Matrix-Aurora rims, but it does not specify rim or tire size. Both the old & new tires are all marked the same..700 x 25 25 - 622......

What am I doing wrong??? What is ERD 603??

jimc101

The ERD is relevant for wheel building, when determing spoke length, but has no relation to tire size / mounting.

The rim you have takes 700c tires, so the 700 x 25 spec should fit, however some tire / rim combos are hard work or just won't play together. have you tried any other brands of tire on this rim?

10 Wheels

What is the tire brand and model?

Thumpic

They are CST compressors; brand new form Niagra........I've got another brand that I'll try........

FastJake

+1

Some tires/rims just don't work well together. I've destroyed a couple tubes trying to remove certain tires before. When that happens those tires go in the junk pile to be put on a bike I'm going to sell...

Are those tires new? I've found old tires generally mount easier than new tires. I've also found folding tires generally mount easier than wire bead tires.

lc911t

Start opposite the valve and end at the valve. According to Michelin, this gives a bit more room for the bead to fall into the channel of the rim.

https://www.michelinbicycletire.com/m...=mounting.view

neurocop

1) I guess you mean that the tire is a tight fit and you puncture the tube while mounting it inside the tire. I've been there and done that. Your rims are 700c and if your tires and tubes are the same you should be ok. Make sure the tube is not oversized; 700 tubes usually come in a range of sizes, e.g. 18-23, 22-25, or something like that. You want the tube range to include your tire width without exceeding it if possible. Bigger than necessary tubes tend to get pinched especially when mounting tight tires. You need to follow good procedure when mounting clincer tires. There are a few different techniques (search on the web). What I do is get one bead in the rim and then get the tube in place and then get the other bead over the rim. I like to do in by hand, but really tight tires will need tire blades to force the issue. Use plastic blades and be careful not to pinch the tube.

2. ERD is effective rim diameter, a parameter that is important in determining the spoke length needed in wheelbuiding. 700c rims have ERD's around 600-610mm, depending on the rim anatomy. ERD is measured between spoke holes from the point where the spoke nipples seat on the rim (not from the outer diameter of the rim edge).

oldbobcat

This really works.

Also consider investing in ultra-thin rim strips--they don't fill in the channel as much, leaving more room for the bead.

mechBgon

Yeah, another vote for thin rim strips. A couple wraps of the narrower Stan's Yellow Tape would be thin and it does NOT shift around, unlike some. Also be aware that Matrix rims earned a reputation for being tight fits, period.

On a practical note, if you're using tire levers to ease the bead over the edge of the rim, stop at 90° so the tip of the lever doesn't pinch the tube against the rim bed.

davidad

https://www.biketoolsetc.com/index.cg...&item_id=KS-TJ

Thumpic

Well I'm done.......this rim will go to the LBS tomorrow for a tire. And I'm adding another step to my bike flipping criteria. I won't buy it if the seat post is stuck...stem is stuck...fork is bent...or it has Aurora rims....

hueyhoolihan

welcome to tube destroyers anonymous. rest assured you have plenty of company.

i usually figure that if i have to resort to a tire iron to install a tire that there is a 50/50 chance of puncturing the tube no matter what i do to prevent it. sometimes i even put it on without the tube just to get the satisfaction that the tire will mount and that i only have to get the tube in there too.

Looigi

What I do is put a very small amount of air in the tube and lube it well with talc. This helps keep it out from under the bead and levers and from getting pinched.

wesmamyke

It's the Matrix rim. Old house brand rims for Trek. They are notorious and equally as difficult as rhyno lites most times.

Buy the Koolstop tire bead jack linked to above, it saves so much time and frustration.