Go Back  Bike Forums > Bike Forums > Cyclocross and Gravelbiking (Recreational)
Reload this Page >

50c tire on 17mm internal width rim?

Cyclocross and Gravelbiking (Recreational) This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like :The Dirty Kanza". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

50c tire on 17mm internal width rim?

Old 09-17-18, 06:29 AM
  #1  
sweetspot
Senior Member
Thread Starter
 
Join Date: Sep 2015
Posts: 99
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 51 Post(s)
Likes: 0
Liked 1 Time in 1 Post
50c tire on 17mm internal width rim?

Alex 470 ATD rim. Soma Cazadero 700x50c tire. No tubeless. Will it work? Will it be safe, especially with low pressure like 30 psi?
sweetspot is offline  
Old 09-17-18, 08:03 AM
  #2  
rumrunn6
Senior Member
 
rumrunn6's Avatar
 
Join Date: Jul 2008
Location: 25 miles northwest of Boston
Posts: 22,892

Bikes: Bottecchia Sprint, GT Timberline 29r

Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 3020 Post(s)
Liked 97 Times in 84 Posts
I'm guessing no, but maybe I shouldn't be replying w/o knowing for sure
rumrunn6 is offline  
Old 09-17-18, 10:24 AM
  #3  
Abe_Froman
Senior Member
 
Abe_Froman's Avatar
 
Join Date: Aug 2016
Location: Chicago
Posts: 2,529

Bikes: Marin Four Corners, 1960's Schwinn Racer in middle of restoration, mid 70s Motobecane Grand Touring, various other heaps.

Mentioned: 75 Post(s)
Tagged: 0 Thread(s)
Quoted: 9286 Post(s)
Liked 40 Times in 35 Posts
Originally Posted by rumrunn6 View Post
I'm guessing no, but maybe I shouldn't be replying w/o knowing for sure
Why not? That combination is like every mountain bike sold in the 90's. 29" vs 700c notwithstanding, but that really has no impact on the rim/tire combo.

Should be absolutely fine IMO, with no issues, save perhaps some squirellyness in sharp corners if you're racing single track or cross on that bike...
Abe_Froman is offline  
Old 09-17-18, 11:26 AM
  #4  
rumrunn6
Senior Member
 
rumrunn6's Avatar
 
Join Date: Jul 2008
Location: 25 miles northwest of Boston
Posts: 22,892

Bikes: Bottecchia Sprint, GT Timberline 29r

Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 3020 Post(s)
Liked 97 Times in 84 Posts
Originally Posted by Abe_Froman View Post
Why not? That combination is like every mountain bike sold in the 90's. 29" vs 700c notwithstanding, but that really has no impact on the rim/tire combo. Should be absolutely fine IMO, with no issues, save perhaps some squirellyness in sharp corners if you're racing single track or cross on that bike...
see there ya go, I was guessing & I shouldn't have, sorry & thanks

here's an article I just came across. looks relevant

https://bikerumor.com/2016/08/12/tec...-best-results/

Last edited by rumrunn6; 09-17-18 at 11:30 AM.
rumrunn6 is offline  
Old 09-17-18, 11:29 AM
  #5  
tyrion
Senior Member
 
tyrion's Avatar
 
Join Date: Oct 2015
Location: San Diego, California
Posts: 2,297

Bikes: Breezer Radar

Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 1202 Post(s)
Liked 70 Times in 47 Posts
You're pushing the boundaries, especially at 30 psi. I bet you'll feel it squirm when cornering hard on pavement. On dirt it won't be so bad. At higher pressure, it won't squirm as much.
tyrion is offline  
Old 09-17-18, 02:28 PM
  #6  
chas58
Senior Member
 
chas58's Avatar
 
Join Date: Jul 2010
Location: Michigan
Posts: 3,558

Bikes: too many of all kinds

Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 704 Post(s)
Liked 34 Times in 28 Posts
Its like every mountain bike I road in the '90s (and still ride today). And yes, going below 35psi can cause serious tire squirm. 30 or below is dangerous on my '90's mountain bikes.

google ETRO chart to get the official answer.
chas58 is offline  
Old 09-17-18, 02:44 PM
  #7  
sjfoote081
Member
 
Join Date: May 2017
Location: Lawrenceville, GA
Posts: 45

Bikes: Trek Crossrip 1, Cannondale Quick 4, Motobecane Fantom 650b

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Gee, I rode my Specialized Hardrock 29er with 17mm internal rims and 2.3 Maxxis tires at low pressure (20 - 25 psi) and found no issues at all. Put lots of singletrack miles on that bike over 5 years and never felt any squirminess whether I was using the standard 1.9 tires or 2.1 or 2.3 tires.
sjfoote081 is offline  
Old 09-17-18, 03:00 PM
  #8  
Abe_Froman
Senior Member
 
Abe_Froman's Avatar
 
Join Date: Aug 2016
Location: Chicago
Posts: 2,529

Bikes: Marin Four Corners, 1960's Schwinn Racer in middle of restoration, mid 70s Motobecane Grand Touring, various other heaps.

Mentioned: 75 Post(s)
Tagged: 0 Thread(s)
Quoted: 9286 Post(s)
Liked 40 Times in 35 Posts
Originally Posted by sjfoote081 View Post
Gee, I rode my Specialized Hardrock 29er with 17mm internal rims and 2.3 Maxxis tires at low pressure (20 - 25 psi) and found no issues at all. Put lots of singletrack miles on that bike over 5 years and never felt any squirminess whether I was using the standard 1.9 tires or 2.1 or 2.3 tires.
I think I experienced what was likely tire deformation for the first time racing cyclocross yesterday on my 35mm tires...you've got to go pretty hard into a corner, or have a serious off camber turn. For 'gravel' riding...I can't imagine squirming/deformation ever being an issue.
Abe_Froman is offline  
Old 09-17-18, 09:32 PM
  #9  
Spoonrobot 
Senior Member
 
Spoonrobot's Avatar
 
Join Date: Jul 2006
Posts: 3,176
Mentioned: 55 Post(s)
Tagged: 0 Thread(s)
Quoted: 984 Post(s)
Liked 25 Times in 21 Posts
How much do you weight?

30 psi is a lot for a 50mm tire.

It'll most likely be fine for the vast majority of your riding. It becomes less fine the faster/harder you plan to corner, especially on rough terrain. On a rim that narrow the sidewalls are less supported so they tend to have a sudden collapse under very hard cornering which depends both on the speed you are riding and the tire pressure. Generally it's easy to suss out the limits but it's also entirely possible to make assumptions based on faulty observations and get into trouble. I'm pretty sure I've had at least one crash - during a mountain bike race - due to not recognizing my tire pressure being too low and cornering too aggressively. I was running 55mm tires on 17mm rims and when I hit enough g force to collapse the sidewall my reaction to compensate caused a high side crash.

The original issue with very wide tires and narrow rims was sidewall failure but tires are significantly better than they were in the late 70s/early 80s. This is an interesting bit of history that served as the foundation for the ETRO chart and a lot of the derivatives. https://web.archive.org/web/20180211...ips/index.html

Chrome translate does a passable job but the pertinent point is:

Too narrow rims lead to increased flexing and thus to flank breakage of the tire directly at the edge of the rim. Depending on what speed.
The little bomb icon on the chart is classic:
Flank break threatens. Who combines so, drives a time bomb.
So in summation, I'd go ahead and do it but ride mindfully and probably don't race on them.
Spoonrobot is offline  
Old 09-18-18, 01:36 AM
  #10  
sweetspot
Senior Member
Thread Starter
 
Join Date: Sep 2015
Posts: 99
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 51 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Thank you for all suggestions. I will give it a try but to be honest i probably will end up in buying a new wider rim. It is not only safety that i am concerned about but also the fact that i already have some toe overlap issues on 43c tire and 50c tire on such norrow rim will be much higher. Wider rim will make tire more wide and less high which is good for me.
sweetspot is offline  
Old 09-18-18, 09:31 AM
  #11  
chas58
Senior Member
 
chas58's Avatar
 
Join Date: Jul 2010
Location: Michigan
Posts: 3,558

Bikes: too many of all kinds

Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 704 Post(s)
Liked 34 Times in 28 Posts
good idea on a wider rim. Granted, I probably ride more aggressive than the people here, but I've had a 54mm tire just roll over to the sidewall and totally wash out landing on pavement. Kinda hurts. Granted, if you are on dirt 100% of the time you won't have this issue, but hard riding with high traction caused problems for me.
chas58 is offline  
Old 09-18-18, 09:34 AM
  #12  
JayNYC
Senior Member
 
JayNYC's Avatar
 
Join Date: Feb 2018
Location: NYC (Harlem)
Posts: 117

Bikes: Fuji Jari 1.3

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 79 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
This webpage says 17mm (internal) is good up to 52mm tires…
https://bikerumor.com/2016/08/12/tec...-best-results/
JayNYC is offline  
Old 09-18-18, 10:00 AM
  #13  
Metieval
Senior Member
 
Metieval's Avatar
 
Join Date: Jul 2005
Location: Ohio
Posts: 1,844

Bikes: Road bike, Hybrid, Gravel, Drop bar SS, hard tail MTB

Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 661 Post(s)
Liked 4 Times in 4 Posts
Originally Posted by chas58 View Post
good idea on a wider rim. Granted, I probably ride more aggressive than the people here, but I've had a 54mm tire just roll over to the sidewall and totally wash out landing on pavement. Kinda hurts. Granted, if you are on dirt 100% of the time you won't have this issue, but hard riding with high traction caused problems for me.
^ this 40c on 13mm internal = ugly mishap on pavement.
__________________
Dawes SST AL, Cannondale Synapse Alloy 105, Giant Talon 29er, Trek Crossrip Elite,
Metieval is offline  
Old 09-19-18, 06:09 AM
  #14  
Kapusta
Cyclochondriac
 
Join Date: Feb 2017
Posts: 2,168
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 901 Post(s)
Likes: 0
Liked 48 Times in 37 Posts
Originally Posted by sweetspot View Post
Wider rim will make tire more wide and less high which is good for me.
Once you reach a certain (very wide) rim width relative to the tire, this is true, but for the rim widths you would be looking at for a 50mm tire, I donít think it will work out that way. Might even be taller, but either way the difference is negligible.

There are good reasons to go with a rim wider than 17mm for a 50mm tire, but making the tire less tall is not one of them..

Here is an interesting thread from another forum with a diagram to illustrate: http://forums.mtbr.com/wheels-tires/...th-756818.html

Last edited by Kapusta; 09-19-18 at 06:15 AM.
Kapusta is offline  
Old 09-19-18, 06:46 AM
  #15  
Spoonrobot 
Senior Member
 
Spoonrobot's Avatar
 
Join Date: Jul 2006
Posts: 3,176
Mentioned: 55 Post(s)
Tagged: 0 Thread(s)
Quoted: 984 Post(s)
Liked 25 Times in 21 Posts
That is a beautiful mess of a thread. Starts out with a bunch of math and theory, pivots to real world measurements that don't quite back up the postulations so moves back to math and theory but obfuscated as "real world models" with "observed measurements" and then fizzles out with no agreement. It's also 7 years old.

Tire height only increases at the narrow margins. Going from something like 13/15 inside diameter to 17/19 may cause a small increase less than 5% of the casing length. 1mm for a 23mm tire.

Anything larger than 13/15 and tire height decreases significantly as the rim gets wider. Going from 17/19 to 21/23 and tire height often decreases by 8-10%. This factor doesn't stay constant but tire height will continue to decrease as the rim gets wider.

99% of the time a 50mm tire is going to get shorter as the rim width goes from 17->19->21->23 and so forth.

One of the major errors the few people who measure height often make is that when moving a tire to a wider rim they inflate to the same pressure as the narrower rim. As a wider rim increases the overall volume inside the tire the same pressure as on a narrower rim actually increases casing strain and causes the tire to appear taller than it would be if the pressure was at the correct level. Flo Cycling has a couple interesting items here: Table 4 Page 6 https://www.flocycling.com/FLO_Cycli...sion_Study.pdf

And this article: FLO Cycling - Casing Tension Study with Union University
Spoonrobot is offline  
Old 09-19-18, 08:50 AM
  #16  
rumrunn6
Senior Member
 
rumrunn6's Avatar
 
Join Date: Jul 2008
Location: 25 miles northwest of Boston
Posts: 22,892

Bikes: Bottecchia Sprint, GT Timberline 29r

Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 3020 Post(s)
Liked 97 Times in 84 Posts
Originally Posted by sjfoote081 View Post
Gee, I rode my Specialized Hardrock 29er with 17mm internal rims and 2.3 Maxxis tires at low pressure (20 - 25 psi) and found no issues at all. Put lots of singletrack miles on that bike over 5 years and never felt any squirminess whether I was using the standard 1.9 tires or 2.1 or 2.3 tires.
hey thanks for sharing that. last night I got worried cuz the 2.25" WTB Riddler PKGing suggested a 19mm minimum inside width but the wheels I was mounting them on measured 18mm if I measured correctly & they seem fine
rumrunn6 is offline  
Old 09-19-18, 11:14 AM
  #17  
Abe_Froman
Senior Member
 
Abe_Froman's Avatar
 
Join Date: Aug 2016
Location: Chicago
Posts: 2,529

Bikes: Marin Four Corners, 1960's Schwinn Racer in middle of restoration, mid 70s Motobecane Grand Touring, various other heaps.

Mentioned: 75 Post(s)
Tagged: 0 Thread(s)
Quoted: 9286 Post(s)
Liked 40 Times in 35 Posts
Originally Posted by Spoonrobot View Post
That is a beautiful mess of a thread. Starts out with a bunch of math and theory, pivots to real world measurements that don't quite back up the postulations so moves back to math and theory but obfuscated as "real world models" with "observed measurements" and then fizzles out with no agreement. It's also 7 years old.

Tire height only increases at the narrow margins. Going from something like 13/15 inside diameter to 17/19 may cause a small increase less than 5% of the casing length. 1mm for a 23mm tire.

Anything larger than 13/15 and tire height decreases significantly as the rim gets wider. Going from 17/19 to 21/23 and tire height often decreases by 8-10%. This factor doesn't stay constant but tire height will continue to decrease as the rim gets wider.

99% of the time a 50mm tire is going to get shorter as the rim width goes from 17->19->21->23 and so forth.

One of the major errors the few people who measure height often make is that when moving a tire to a wider rim they inflate to the same pressure as the narrower rim. As a wider rim increases the overall volume inside the tire the same pressure as on a narrower rim actually increases casing strain and causes the tire to appear taller than it would be if the pressure was at the correct level. Flo Cycling has a couple interesting items here: Table 4 Page 6 https://www.flocycling.com/FLO_Cycli...sion_Study.pdf

And this article: FLO Cycling - Casing Tension Study with Union University
That doesn't make any sense. Rim width should not have any impact on casing tension. The volume of air in the tire makes zero difference, only the surface area of the interior of the tire matters. And that is not going to change with rim width.
Abe_Froman is offline  
Old 09-19-18, 01:20 PM
  #18  
rumrunn6
Senior Member
 
rumrunn6's Avatar
 
Join Date: Jul 2008
Location: 25 miles northwest of Boston
Posts: 22,892

Bikes: Bottecchia Sprint, GT Timberline 29r

Mentioned: 87 Post(s)
Tagged: 0 Thread(s)
Quoted: 3020 Post(s)
Liked 97 Times in 84 Posts
side note, regarding casing strain ...

after mounting 2 40mm tires on Trek FX wheels to 50psi, was happily doing the same with the 2.25s on a 18mm inside rim but past 40psi the pump was having some trouble going higher & tire starting making some questionable sounds (now "casing strain" sounds like a good description) so I stopped & checked the packaging which said to use only between 30-40 psi. so I bled some air out & settled on 30 (with a burp) for the front & 40 (with a burp) for the rear (so they might be 5lbs under those #s ) if I remember correctly they measure 53mm after being mounted (not 57.15mm)

rumrunn6 is offline  
Old 09-20-18, 12:50 PM
  #19  
Kapusta
Cyclochondriac
 
Join Date: Feb 2017
Posts: 2,168
Mentioned: 18 Post(s)
Tagged: 0 Thread(s)
Quoted: 901 Post(s)
Likes: 0
Liked 48 Times in 37 Posts
Originally Posted by Spoonrobot View Post
That is a beautiful mess of a thread. Starts out with a bunch of math and theory, pivots to real world measurements that don't quite back up the postulations so moves back to math and theory but obfuscated as "real world models" with "observed measurements" and then fizzles out with no agreement. It's also 7 years old.

Tire height only increases at the narrow margins. Going from something like 13/15 inside diameter to 17/19 may cause a small increase less than 5% of the casing length. 1mm for a 23mm tire.

Anything larger than 13/15 and tire height decreases significantly as the rim gets wider. Going from 17/19 to 21/23 and tire height often decreases by 8-10%. This factor doesn't stay constant but tire height will continue to decrease as the rim gets wider.

99% of the time a 50mm tire is going to get shorter as the rim width goes from 17->19->21->23 and so forth.

One of the major errors the few people who measure height often make is that when moving a tire to a wider rim they inflate to the same pressure as the narrower rim. As a wider rim increases the overall volume inside the tire the same pressure as on a narrower rim actually increases casing strain and causes the tire to appear taller than it would be if the pressure was at the correct level. Flo Cycling has a couple interesting items here: Table 4 Page 6 https://www.flocycling.com/FLO_Cycli...sion_Study.pdf

And this article: FLO Cycling - Casing Tension Study with Union University
OK, I am going to push back on a few things here:

The thread I linked to..
1- That thread is far from a "mess", unless you consider reading what a professional tire developer (bholwell) knows on the matter. There is actually a lot of very good info in there.

2- You have a few mathematical models (including from the professional tire developer) being thrown out there all showing the same thing: that until rim width starts approaching close to the tire width, the height INCREASES, though (and this is also a key point) this increase is very small.

3- You have general agreement that there are a number of confounding factors that make these very small differences hard to measure in practice.

4- You have Derby (of Derby Rims) measuring tires on different width rims, and coming to the conclusion that the difference in height is negligible. Shiggy's mtb tire site (where he used to measure tires fanatically) does not seem to be up anymore, but as I remember, (I was in that thread, if you did not notice) he was not posting anything that significantly contradicted the mathematical claims. Certainly did not show the tires getting shorter (that clearly would have been addressed).

5- bholwell actaully addressed casing stretching in that thread.

6- You are incorrect that the thread fizzles with no agreement. Everyone in the thread agrees that tires will theoretically increase a very small amount with tire width, though just how much is not settled. NOBODY - not Derby (of Derby Rims), or bholwell (from Maxxis and CST) or Shiggy (who has neurotically put calipers to more tires than any human being alive) - indicate that tires will get narrower with increasing widths (within typical mtb widths). The areas of disagreement were very much nuanced points and did not question the underlying premise.

7- The fact that the thread is 7 years old is utterly irrelevant.

Casing strain
That is an interesting and well done article you linked to, but it does not really back up your point. When you look at Table 4 Page 6, it does show height increasing with pressure, but look at the actual numbers! It shows the height increases roughly ~0.01" (~0.25mm) per 20 psi increase. That is essentially meaningless. And consider that in reality going to a wider rim on a tire in the 50mm range will, in the real world, mean a drop of 10 psi MAX. So now we are talking what... 0.13mm difference? Even if you scale that up from a 25mm tire to a 50 mm tire, that's ~0.025mm. Basically nothing.

Anything larger than 13/15 and tire height decreases significantly as the rim gets wider. Going from 17/19 to 21/23 and tire height often decreases by 8-10%. This factor doesn't stay constant but tire height will continue to decrease as the rim gets wider.

99% of the time a 50mm tire is going to get shorter as the rim width goes from 17->19->21->23 and so forth.
Where are you getting these numbers from? They don't make theoretical sense for a 50mm tire, and the only actual measured data I have seen does not back this up for a set of tires 2.1" range. You got some other source on this?

I could believe this if we were talking about a ~19mm wide tire, but not a 50mm tire. I think the confusion here may be that you are assuming the 50mm tire will behave the same way as a 23mm tire. It won't, because it is the width of the rim relative to the size of the tire, that determines if the tire will get taller or shorter.

Unless the OP is looking at a rim close to 50mm wide, I just can't see how a wider rim (like going from a 17mm to 25mm rim) could possible make the tire shorter..

Last edited by Kapusta; 09-20-18 at 12:55 PM.
Kapusta is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Andy_K
Cyclocross and Gravelbiking (Recreational)
0
02-11-13 04:48 PM
superduper54
Singlespeed & Fixed Gear
8
07-03-09 01:48 PM
donrhummy
Road Cycling
65
04-16-08 03:57 AM
Jet Travis
Fifty Plus (50+)
0
01-21-08 04:47 PM
xcracer13
Mountain Biking
5
09-14-07 04:22 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

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.