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Rims too tight -- sandpaper them down?

Old 05-16-21, 08:03 PM
  #126  
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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?
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Old 05-16-21, 08:15 PM
  #127  
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Originally Posted by tgot View Post
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.
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Old 05-17-21, 06:41 AM
  #128  
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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.
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Old 05-17-21, 10:07 AM
  #129  
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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.
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Old 05-17-21, 07:50 PM
  #130  
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Originally Posted by jadocs View Post
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"
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Old 05-17-21, 08:14 PM
  #131  
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Originally Posted by jesnow View Post
My wife agrees with growlerdinky and them and thinks I'm an idiot for even contemplating it.
Listen to your wife.
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Old 06-10-21, 12:19 PM
  #132  
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So, how did it go?
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Old 06-10-21, 06:24 PM
  #133  
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Originally Posted by growlerdinky View Post
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.
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Old 06-10-21, 11:05 PM
  #134  
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Old 06-11-21, 09:06 PM
  #135  
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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.
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Old 06-12-21, 12:21 PM
  #136  
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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.
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Old 07-08-21, 05:24 PM
  #137  
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nothing?
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Old 07-12-21, 10:29 AM
  #138  
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Originally Posted by growlerdinky View Post
nothing?
OP hasn't logged in since 5/5. R.I.P.
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Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
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Old 07-17-21, 07:51 AM
  #139  
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R.I.P = Rims In Pieces
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Old 07-17-21, 11:48 PM
  #140  
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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.
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Old 07-18-21, 11:28 AM
  #141  
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Originally Posted by CliffordK View Post
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.
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Old 07-18-21, 01:39 PM
  #142  
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Originally Posted by jesnow View Post
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
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Old 09-20-22, 03:11 PM
  #143  
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Im starting to get worried
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Old 09-20-22, 05:02 PM
  #144  
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Originally Posted by preventec47 View Post
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!
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Old 09-21-22, 09:55 AM
  #145  
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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
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Old 09-22-22, 01:12 PM
  #146  
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Originally Posted by Dsprok View Post
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.
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Old 09-26-22, 05:45 AM
  #147  
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I think it would work, but I'd go with the grinder instead of sanding, mostly because I like sparks...
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Old 09-26-22, 06:47 AM
  #148  
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Originally Posted by wheelreason View Post
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.
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Old 09-26-22, 03:12 PM
  #149  
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OP thanks for posting instead of just doing it. Always enjoyable to read threads like these.

They're your wheels, do what you want.
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Old 09-27-22, 06:28 AM
  #150  
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Originally Posted by jadocs View Post
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.
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