Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Swapping road tires onto a mountain bike

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Swapping road tires onto a mountain bike

Old 06-05-11, 08:17 AM
Junior Member
Thread Starter
Join Date: May 2011
Location: Eau Claire, WI
Posts: 16
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Swapping road tires onto a mountain bike

I bought some new 26x1.5 smooth tires for my mountain bike. And I also got some 26x1.5-1.75 tubes. My current tires are 26x2.125. When I put the new tube partially inflated around my rim, there was a ton of slack! Like if I bunched it all together, it came off the rim more than an inch. Is this normal? Do I need to get different tubes? What gives?
dmikester1 is offline  
Old 06-05-11, 08:24 AM
Senior Member
Join Date: Oct 2007
Location: West Yorkshire, United Kingdom
Posts: 5,736
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 431 Post(s)
Liked 81 Times in 70 Posts
So what happens when the tubes are fully inflated? The tubes you say you (26x1.5-1.75) have should be compatiable with 26x1.5 tires
jimc101 is offline  
Old 06-05-11, 10:08 AM
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 36,721

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 131 Post(s)
Tagged: 1 Thread(s)
Quoted: 4751 Post(s)
Likes: 0
Liked 747 Times in 466 Posts
Tubes have the strength and properties of the toy balloons that clowns make animal figures out of. When you fill them they get longer and fatter and will keep doing so until they burst.

The tube is just an air bladder so it's meaningless ot consider it's inflated size compared to the rim. It's the tire that determines size, fit and shape and once stuffed into the tire the tube will expand until it fills all available space.

BTW- as a side note, I prefer tubes that are longer vs shorter (within the usable range). They stay stuffed well up in the tire while short ones, tend to pull down making a pain of themselves while mounting and increasing the risk of a pinch puncture. You've got a good thing there, so enjoy it until your next tube is on the shorter side and you see what I mean.
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Old 06-05-11, 10:53 AM
Join Date: Jun 2010
Location: NW,Oregon Coast
Posts: 43,599

Bikes: 8

Mentioned: 197 Post(s)
Tagged: 0 Thread(s)
Quoted: 7607 Post(s)
Liked 1,343 Times in 850 Posts
There may be Creases, in the tube, when installed in a smaller tire,
It wont cost much to get tubes for your chosen 1,5 width.

set the wider tires and tubes aside as a set.
for reinstalling for Dirt riding episodes.
fietsbob is offline  
Old 06-05-11, 11:11 AM
Bianchi Goddess
Bianchigirll's Avatar
Join Date: Apr 2009
Location: Shady Pines Retirement Fort Wayne, In
Posts: 29,139

Bikes: Too many to list here check my signature.

Mentioned: 170 Post(s)
Tagged: 2 Thread(s)
Quoted: 2676 Post(s)
Liked 2,088 Times in 1,176 Posts
you put the tube on the rim first? I usually, and I think most people do too, put a bit of air in the tube to give it shape then put it in the tire. then starting att he valve I put both beads in the rim. then I work the side furtherest from me on to the rim, and then side closest. a x1.75 tube should be fine in a x1.5 tire.
One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"

Sugar "Kane" Kowalczyk
Bianchigirll is offline  
Old 06-05-11, 11:32 AM
Cottered Crank
Amesja's Avatar
Join Date: Aug 2010
Location: Chicago
Posts: 3,493

Bikes: 1954 Raleigh Sports 1974 Raleigh Competition 1969 Raleigh Twenty 1964 Raleigh LTD-3

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Likes: 0
Liked 8 Times in 4 Posts
If a tube is a bit on the long side for the tire and one is afraid of it folding or doubling over inside the tire it is best to inflate the tire to about 80% of target pressure and seat the bead on the rim once. After this deflate it back down to the point where the tire is almost floppy again on the rim before filling it back up once more. This allows the tube to center itself better inside the jacket of the tire and any folds or creases will work themselves out. If it is REALLY bad you can do it once more just to be sure.

In motorcycle tube-type tires this makes a HUGE difference in the lifespan of tires -especially in off-road racing where tires have run with lower pressure and the larger tubes can really get kinked up inside the larger tires.

Unlike others who like to have a tube partially inflated, I completely squeeze ALL the air out of a bicycle tube by rolling it up flat with the stem removed before re-inserting the stem. They store better this way when they are spares and I find it is easier to stuff them flat all the way up inside the tire carcass before installing the tire on the rim. This does not work with moto tires as you must first seat one bead, install the tube and then lever the last bead carefully onto the tire. Once you have done a few dozen motorcycle tires doing bicycle tires is a cakewalk. I don't think I've ever pinched a bicycle tube during installation since the 1970's when I mastered motorcycle tires.
Amesja is offline  
Old 06-05-11, 03:11 PM
Certified Bike Brat
Burton's Avatar
Join Date: Jan 2011
Location: Montreal, Quebec
Posts: 4,251
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
The dimensions you posted say the tube is the correct size so my bet is that you put too much air in it initially. Let some out and you`ll find the size magically decreases and will fit your rim.
Burton is offline  
Old 06-05-11, 03:58 PM
cowboy, steel horse, etc
LesterOfPuppets's Avatar
Join Date: Sep 2008
Location: Valley of the Sun.
Posts: 40,651

Bikes: everywhere

Mentioned: 70 Post(s)
Tagged: 1 Thread(s)
Quoted: 9857 Post(s)
Liked 4,816 Times in 2,520 Posts
Occasionally I get tubes that have too big a diameter. It's not pretty stuffing them in all wrinkly, but I never had problems once I got 'em in the tire and made sure they weren't pinched under the bead.

I'm glad I haven't had a bad one in a while. I had a bad rash of them in the early aughts. All 700c/27" tubes, though.
LesterOfPuppets is online now  
Old 06-05-11, 08:15 PM
Junior Member
Thread Starter
Join Date: May 2011
Location: Eau Claire, WI
Posts: 16
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Wow, thanks for all the tips guys. I was planning on putting it in the tire first, but I just put it around the rim to see what it would look like and was just surprised by all the slack. Glad to hear that is not problem. I will proceed with putting on my new street tires and tubes! Thanks again!
dmikester1 is offline  
Related Topics
Thread Starter
Last Post
Bicycle Mechanics
05-31-18 03:54 AM
Singlespeed & Fixed Gear
08-17-17 02:49 PM
Bicycle Mechanics
06-12-15 10:42 AM
Bicycle Mechanics
03-23-15 11:13 PM
Classic & Vintage
03-03-15 09:25 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell or Share My Personal Information -

Copyright © 2023 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.