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

Rims too tight -- sandpaper them down?

Notices
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.

Rims too tight -- sandpaper them down?

Old 05-16-21, 08:03 PM
  #126  
tgot 
Full Member
 
Join Date: Jan 2009
Location: SF Peninsula
Posts: 443

Bikes: 1986 Centurion Ironman, 1997 Trek 2120, Trek T1000

Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 137 Post(s)
Liked 203 Times in 116 Posts
OP gone?

The OP hasn't come back with a report on how the experiment went, has he?

Are we all assuming he was killed in the attempt?
tgot is offline  
Likes For tgot:
Old 05-16-21, 08:15 PM
  #127  
Skulking
Senior Member
 
Join Date: Aug 2020
Posts: 79
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 57 Post(s)
Liked 106 Times in 39 Posts
Originally Posted by tgot
The OP hasn't come back with a report on how the experiment went, has he?

Are we all assuming he was killed in the attempt?
That's the only reasonable assumption to make. Fortunately, the next time someone asks this question we will now have this thread to point them to so they can understand why it's a bad idea.
Skulking is offline  
Likes For Skulking:
Old 05-17-21, 06:41 AM
  #128  
bmalmquist
Wrench User
 
Join Date: Nov 2007
Posts: 131
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 3 Times in 2 Posts
Analogies

I have followed this thread since it started, but did not chime in because it seemed like the OP was asking for validation to do something ill-advised. I honestly hope the OP's fever broke moments before sandpaper/grinding wheel/lathe touched aluminum and they found some different tires or wheels. Whatever their fate, it seems the OP is gone and this thread becomes an informative and cautionary post to those who come after. To that end, anyone have any good analogies for this scenario?

I landed on it being akin to a skydiver intentionally fraying their parachute backpack straps because the pack was difficult to take off when on the ground.
bmalmquist is offline  
Likes For bmalmquist:
Old 05-17-21, 10:07 AM
  #129  
jadocs
Senior Member
 
jadocs's Avatar
 
Join Date: Jul 2018
Location: USA
Posts: 2,192

Bikes: Ti, Mn Cr Ni Mo Nb, Al, C

Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 942 Post(s)
Liked 526 Times in 349 Posts
The problem is the logic behind modifying a non wear/disposable item (rim) over a wear/disposable item (tire). Conte 5000's are known to be tight on many rims to begin with. With respect to the OP, there is one of two things going on.

1. The rim is out of spec - return it or exchange it. Chinese or not $400-$500 is still $400-$500.

2. The rim is in spec - Use the tricks to mounting tight tires (putting them in hot water, soap them up, mounting technique, etc...) or change tire brands if its more important to be able to remove and mount by hand on the side of the road.

Modifying the wheel is not a good idea for many of the reasons listed on this thread. What you need to be considering is why are Chinese rims cheaper? Are they the same quality (materials, workmanship)? If your answer is no then that's more reason not to modify them.
jadocs is offline  
Old 05-17-21, 07:50 PM
  #130  
veganbikes
Clark W. Griswold
 
Join Date: Mar 2014
Location: ,location, location
Posts: 13,227

Bikes: Foundry Chilkoot Ti W/Ultegra Di2, Salsa Timberjack Ti, Cinelli Mash Work RandoCross Fun Time Machine, 1x9 XT Parts Hybrid, Co-Motion Cascadia, Specialized Langster, Phil Wood Apple VeloXS Frame (w/DA 7400), R+M Supercharger2 Rohloff, Habanero Ti 26

Mentioned: 54 Post(s)
Tagged: 0 Thread(s)
Quoted: 4230 Post(s)
Liked 3,841 Times in 2,563 Posts
Originally Posted by jadocs
The problem is the logic behind modifying a non wear/disposable item (rim) over a wear/disposable item (tire). Conte 5000's are known to be tight on many rims to begin with. With respect to the OP, there is one of two things going on.

1. The rim is out of spec - return it or exchange it. Chinese or not $400-$500 is still $400-$500.

2. The rim is in spec - Use the tricks to mounting tight tires (putting them in hot water, soap them up, mounting technique, etc...) or change tire brands if its more important to be able to remove and mount by hand on the side of the road.

Modifying the wheel is not a good idea for many of the reasons listed on this thread. What you need to be considering is why are Chinese rims cheaper? Are they the same quality (materials, workmanship)? If your answer is no then that's more reason not to modify them.
You forget that the OP has already used all of the tricks and knows every single one that can ever and will ever exist. They just wanted you to say "yes you should start sanding down your rim it is a smart idea and you are a bigly and smartly person who came up with the greatest idea"
veganbikes is offline  
Likes For veganbikes:
Old 05-17-21, 08:14 PM
  #131  
oldbobcat
Senior Member
 
oldbobcat's Avatar
 
Join Date: Jul 2005
Location: Boulder County, CO
Posts: 4,361

Bikes: '80 Masi Gran Criterium, '12 Trek Madone, early '60s Frejus track

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 502 Post(s)
Liked 431 Times in 328 Posts
Originally Posted by jesnow
My wife agrees with growlerdinky and them and thinks I'm an idiot for even contemplating it.
Listen to your wife.
oldbobcat is offline  
Likes For oldbobcat:
Old 06-10-21, 12:19 PM
  #132  
growlerdinky
Duke Ulysses
 
Join Date: Jul 2013
Location: Southern California
Posts: 800

Bikes: An old orange one for dirt, and for the other stuff: a white one, a kinda mint green one, and a black one.

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 165 Post(s)
Liked 175 Times in 86 Posts
So, how did it go?
growlerdinky is offline  
Old 06-10-21, 06:24 PM
  #133  
SoSmellyAir
Method to My Madness
 
Join Date: Nov 2020
Location: Orange County, California
Posts: 3,529

Bikes: Trek FX 2, Cannondale Synapse, Cannondale CAAD4, Santa Cruz Stigmata GRX

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 1867 Post(s)
Liked 1,406 Times in 975 Posts
Originally Posted by growlerdinky
So, how did it go?
This is a prime example of diligence in following up. If only my former assistant was half this diligent, she would not have become my former assistant.
SoSmellyAir is offline  
Likes For SoSmellyAir:
Old 06-10-21, 11:05 PM
  #134  
Rolla
Guest
 
Join Date: Sep 2020
Posts: 2,888
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 1346 Post(s)
Liked 3,269 Times in 1,439 Posts
Rolla is offline  
Likes For Rolla:
Old 06-11-21, 09:06 PM
  #135  
adipe
Senior Member
 
Join Date: Aug 2015
Posts: 156
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 51 Post(s)
Liked 11 Times in 10 Posts
how much does a 622mm 500g rim compress (change diameter) if average spoke tension is ~120kgf DS and ~70kgf NDS for 32 spokes?...
73GPa modulus in compression...

a rough estimation would be 0.7mm. maybe wheel was a sloppy build. they all add up. improper tire mounting technique, rim/tire combo (one or the other being non standard)... and spoke tension variance along with low average spoke tension.

oh wait... chinese carbon rims. i dunno the modulus for that, someone else knows perhaps?...

later edit: CF about 7 times stiffer (in compression) than aluminum (considering modulus and density differences).
then it's trick or treat.

Last edited by adipe; 06-11-21 at 09:27 PM.
adipe is offline  
Old 06-12-21, 12:21 PM
  #136  
preventec47
Junior Member
 
Join Date: Jun 2017
Location: Atlanta, GA
Posts: 155
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Likes: 0
Liked 40 Times in 28 Posts
The diameter/circumference of the outer edge of the rim does not determine the tightness when installing a tire. If the depth to the bottom of the inner part of the
rim is greater, then on the other side of the rim, the beads of the tire can be pulled down into the rim deeper making the rire easier to mount by giving more slack on the
side of the rim you are trying to push the beads over on.. Further, some rim designs differ in the distance between where the bead of the tire seats and the outer most
edge of the rim. Clearly some rim designs would be easier to mount than others even when the bead ridge measurements are the same dimensions.
preventec47 is offline  
Likes For preventec47:
Old 07-08-21, 05:24 PM
  #137  
growlerdinky
Duke Ulysses
 
Join Date: Jul 2013
Location: Southern California
Posts: 800

Bikes: An old orange one for dirt, and for the other stuff: a white one, a kinda mint green one, and a black one.

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 165 Post(s)
Liked 175 Times in 86 Posts
nothing?
growlerdinky is offline  
Old 07-12-21, 10:29 AM
  #138  
ThermionicScott 
working on my sandal tan
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Posts: 22,620

Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)

Mentioned: 98 Post(s)
Tagged: 0 Thread(s)
Quoted: 3868 Post(s)
Liked 2,559 Times in 1,574 Posts
Originally Posted by growlerdinky
nothing?
OP hasn't logged in since 5/5. R.I.P.
__________________
Originally Posted by chandltp
There's no such thing as too far.. just lack of time
Originally Posted by noglider
People in this forum are not typical.
RUSA #7498
ThermionicScott is offline  
Old 07-17-21, 07:51 AM
  #139  
Bimmer69
Junior Member
 
Bimmer69's Avatar
 
Join Date: Aug 2020
Location: Toronto, Canada
Posts: 96
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Liked 40 Times in 26 Posts
R.I.P = Rims In Pieces
Bimmer69 is offline  
Likes For Bimmer69:
Old 07-17-21, 11:48 PM
  #140  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 27,600
Mentioned: 217 Post(s)
Tagged: 0 Thread(s)
Quoted: 18302 Post(s)
Liked 4,470 Times in 3,326 Posts
Ok, a little late here.

I'm not sure I'd be too excited about modifying a $1000 pair of rims. However, might as well make sure the wheels work for a person.

As far as accurately measuring one's progress. If the wheel was trued to start with, one could use a truing stand with a dial micrometer to monitor the hop.

I think one could get fairly close simply eyeballing it with respect to the bead hook. Or, grind a block to fit inside the rim to use to measure one's progress.

I'm not convinced taking say 0.5mm off from beyond the hook would make a rim with a fully inflated tire suddenly start blowing beads, assuming there is adequate material to not compromise the hook. If it does blow beads, then the tire is way too loose already.
CliffordK is offline  
Old 07-18-21, 11:28 AM
  #141  
Germany_chris
I’m a little Surly
 
Germany_chris's Avatar
 
Join Date: Jan 2010
Location: Near the district
Posts: 2,426

Bikes: Two Cross Checks, a Karate Monkey, a Disc Trucker, and a VO Randonneur

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 698 Post(s)
Liked 1,290 Times in 644 Posts
Originally Posted by CliffordK
Ok, a little late here.

I'm not sure I'd be too excited about modifying a $1000 pair of rims. However, might as well make sure the wheels work for a person.

As far as accurately measuring one's progress. If the wheel was trued to start with, one could use a truing stand with a dial micrometer to monitor the hop.

I think one could get fairly close simply eyeballing it with respect to the bead hook. Or, grind a block to fit inside the rim to use to measure one's progress.

I'm not convinced taking say 0.5mm off from beyond the hook would make a rim with a fully inflated tire suddenly start blowing beads, assuming there is adequate material to not compromise the hook. If it does blow beads, then the tire is way too loose already.
I don’t think it’d cause issues either but stretching the tires is simpler, safer, and easier.
Germany_chris is offline  
Old 07-18-21, 01:39 PM
  #142  
tendency 
Full Member
 
Join Date: Jul 2008
Posts: 469
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 236 Post(s)
Liked 170 Times in 104 Posts
Originally Posted by jesnow
I have some new rims that are super tight with my preferred tires. I'm very experienced, and still broke two tire levers getting them on there (which I ultimately did). The tires aren't tight on any of my other wheels. I think it's the tubeless-ready idea biting me in the ass. Manufacturers are deliberately making them tight by adding a tiny amount to the circumference of the rim. But I'll *never* get those things on out on a ride! It doesn't matter what tricks there are in the shop to mount a tire if you're screwed from the get go on a ride in the middle of nowhere. I have to be able to get the thing mounted in seconds not hours.

My question: Has anybody ever sanded down the outside of the rim? Wet/dry sandpaper, 100 grit will take them right down, then 600 grit to smooth them. Aluminum is soft, WC wet/dry sandpaper is hard, this will work very quickly. People regularly sand out ding marks and such. But I've never heard of anybody sanding down a rim to improve tubeful tire fit in "tubeless-ready" rims.

Has anybody ever tried it?

Please do *not* reply to this thread with other advice for getting tires onto the rim, I'm asking a very specific question. I know *all* the tricks already thank you. This is maybe a new one.

Cheers,

Jon.
You must first spend five years developing what the Zen practitioners call 'beginner's mind'. Maybe 10 years in your case
tendency is offline  
Old 09-20-22, 03:11 PM
  #143  
growlerdinky
Duke Ulysses
 
Join Date: Jul 2013
Location: Southern California
Posts: 800

Bikes: An old orange one for dirt, and for the other stuff: a white one, a kinda mint green one, and a black one.

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 165 Post(s)
Liked 175 Times in 86 Posts
Im starting to get worried
growlerdinky is offline  
Old 09-20-22, 05:02 PM
  #144  
Sonofamechanic 
Go Ride!
 
Join Date: May 2019
Location: Minnesota—55346
Posts: 267

Bikes: Klein Quantum Pro, Klein Attitude, Azuki SS, Merckx AXM, Klein Quantum Race, Klein Quantum

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 109 Post(s)
Liked 149 Times in 86 Posts
Originally Posted by preventec47
The diameter/circumference of the outer edge of the rim does not determine the tightness when installing a tire. If the depth to the bottom of the inner part of the
rim is greater, then on the other side of the rim, the beads of the tire can be pulled down into the rim deeper making the rire easier to mount by giving more slack on the
side of the rim you are trying to push the beads over on.. Further, some rim designs differ in the distance between where the bead of the tire seats and the outer most
edge of the rim. Clearly some rim designs would be easier to mount than others even when the bead ridge measurements are the same dimensions.
FINALLY!!!! I had to read thru 6 pages to get to someone thinking this question thru all the way….To re-phrase the above, when you are pushing that last bit of tire bead over the rim, 90% of your bead is pushing against the inside bed (center) of the rim, NOT the outer edge…so yes, you can sand down a few microns without going horribly out of balance or weakening the rim for “around town” use, but at the same time, do a bit of sanding inside the rim to get that bed down—a few microns there (if you think the bed is thick enough to handle a bit of “sandpaper wear”) will have a greater impact. A very smart early post mentioned replacing the rim tape with thinner stuff…even more brilliant.
Jon…your patience is admirable—you asked a question you knew was outlandish and kept your head when the ******** started to fly. Think about where that tire is bedding—that’s what’s too ‘big’— maybe compare that measure with the other rim? Best of luck!
Sonofamechanic is offline  
Old 09-21-22, 09:55 AM
  #145  
70sSanO
Senior Member
 
70sSanO's Avatar
 
Join Date: Feb 2015
Location: Mission Viejo
Posts: 5,750

Bikes: 1986 Cannondale SR400 (Flat bar commuter), 1988 Cannondale Criterium XTR, 1992 Serotta T-Max, 1995 Trek 970

Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1927 Post(s)
Liked 2,143 Times in 1,309 Posts
In light of the actual measurement of a micron, yes I agree the OP can certainly remove a “few” of them from anywhere on a rim.

John
70sSanO is online now  
Likes For 70sSanO:
Old 09-22-22, 01:12 PM
  #146  
yannisg
Senior Member
 
Join Date: Feb 2011
Location: NW Peloponnese, Greece
Posts: 546
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 112 Post(s)
Likes: 0
Liked 25 Times in 22 Posts
Originally Posted by Dsprok
If you must marry that particular tire to that rim.....sitting down? Put the rim in a freezer put the tire in hot sun wait a couple hours and 'git it done'
Never tried the freezer, but the sun definitely works. The sun is quite hot here.
yannisg is offline  
Old 09-26-22, 05:45 AM
  #147  
wheelreason
Senior Member
 
Join Date: Aug 2009
Posts: 1,691
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 458 Post(s)
Liked 554 Times in 329 Posts
I think it would work, but I'd go with the grinder instead of sanding, mostly because I like sparks...
wheelreason is offline  
Old 09-26-22, 06:47 AM
  #148  
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,911

Bikes: Several, mostly not name brands.

Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3556 Post(s)
Liked 3,332 Times in 1,899 Posts
Originally Posted by wheelreason
I think it would work, but I'd go with the grinder instead of sanding, mostly because I like sparks...
Not with an aluminum rim. Aluminum doesn't spark, and it will clog your grinding wheel, increasing risk of thermal cracking and shrapnel later on.
JohnDThompson is offline  
Likes For JohnDThompson:
Old 09-26-22, 03:12 PM
  #149  
trucklet
good cheap fun
 
trucklet's Avatar
 
Join Date: Jan 2022
Location: Lansing, MI
Posts: 49

Bikes: Too many

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Liked 47 Times in 17 Posts
OP thanks for posting instead of just doing it. Always enjoyable to read threads like these.

They're your wheels, do what you want.
trucklet is offline  
Likes For trucklet:
Old 09-27-22, 06:28 AM
  #150  
sweeks
Senior Member
 
sweeks's Avatar
 
Join Date: Sep 2004
Location: Chicago area
Posts: 2,535

Bikes: Airborne "Carpe Diem", Motobecane "Mirage", Trek 6000, Strida 2, Dahon "Helios XL", Dahon "Mu XL", Tern "Verge S11i"

Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 972 Post(s)
Liked 572 Times in 393 Posts
Originally Posted by jadocs
The problem is the logic behind modifying a non wear/disposable item (rim) over a wear/disposable item (tire).
Rims are wear items on bikes with rim brakes depending on mileage and weather conditions. A different order of magnitude, but they can wear out.


Brake wear causing rim crack.



Using a straight-edge to assess rim wear.
sweeks is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.