# Minimum Rim Width 2.8, 3.0, 3.25, 3.8?



## PHeller (Dec 28, 2012)

I've been running 275x2.6 tires for about a year now on my comparatively narrow 25mm internal rims. Aside from some tricky air pressure and not so fun squirming after larger drops, nothing really bad has happened with this combo.

I've got a new frame now, one with 96mm between chainstays, so I could comfortably fit a 85mm tire in the back. Thing is, I don't want a dedicated Plus wheelset. I want the ability to run 275x2.4 tires or 275x3.5 or (3.8) tires. So I wondered, is there some way of comparing numbers to determine what tire-to-rim-ratio I might currently be accustomed to, versus what is the max tire I could run on a 35mm internal rim?

If we convert 2.6" to mm, we get *66mm, divide that by 25mm (my current rim width) and we get a tire-to-rim-ratio (TTRR) of 2.64.* The tire is roughly 2.64 times wider than the rim.

So, we can extrapolate that and say something like a *3.8 tire on a 35mm rim is TTRR of 2.74.* Not that much worse.

While running a 3.8" tires on a 35mm rim wouldn't be ideal, *the industry has long been running 2.3 tires (58mm) on 20mm internal rims, resulting in a TTRR of 2.9!* We're already quite accustomed to big tires on little rims.

But, all of this is just numbers and theory, and so I'd like to get some feedback. *For purposes of safety (not performance) what is minimum rim width you'd run on a 3", 3.2", or 3.8" tire?*

I know we say that these tires perform better with wider rims, but from a safety standpoint, can we adjust tire width to fit a specific frame by running narrower or wider rims? Of course the other factor is that of tire selection. It may be easier to get a wider rim to use with common 3" tires (and get full 3" width) than to use narrow rims with relatively less common 3.25 or 3.8" tires (and pull the tire to a narrower 3.5").

Here's Bike Radar's take on the subject.


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## chelboed (Jul 29, 2005)

If you have a set of 2.4" tires and 3.8" tires and only use 1x rim to run either...you're always going to be suboptimal.

A 3" tire with an i40 is as narrow as I'd wanna go and there's no way I'd run a 2.4" tire on that.


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## Impetus (Aug 10, 2014)

It seems the industry is still sorting this out. 

Maxxis says nothing narrower than i40 for a 3.0 (per the tag on the tires)
Stan's says i32 is good for 2.8, and i34 is fine for 3.0 (per the website)
Jones Bikes says i45-i50 is really nice for 2.4's (taken from somewhere on his site FAQ)



I personally think i40 is good for 3.0s. I have i43s and love them, but when I mounted a 2.4 to it, it went on fine, but was too square for my liking. I actually began my plus riding with 3.0s on i30s and wasn't super impressed. I'm a fan of wider is better, other's prefer narower. 

I suspect that in the near future we'll start to hone in on an accepted ratio of tire/rim as the OP mentioned. 

If I had to guess, I think that ratio will eventually fall between 1.8 and 2.1
For reference, that's between i36 and i43 for a 3.0. 

I also have run 2.6's on i30 and thought it was really nice, but I like real plus tires.


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## mikesee (Aug 25, 2003)

The answer is always going to be "It depends". And the dependencies are your height/weight/riding style, your preferences, your past, present, and future hang-ups, the types of trails you ride, the trail/soil/snow conditions, preferred tire pressures (actual vs. measured), casing construction, and, of course, angle of the dangle.

"The industry" hasn't sorted this out, and truthfully won't. Too many options, too many people, too many preferences.


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## bdundee (Feb 4, 2008)

mikesee said:


> The answer is always going to be "It depends". And the dependencies are your height/weight/riding style, your preferences, your past, present, and future hang-ups, the types of trails you ride, the trail/soil/snow conditions, preferred tire pressures (actual vs. measured), casing construction, and, of course, angle of the dangle.
> 
> "The industry" hasn't sorted this out, and truthfully won't. Too many options, too many people, too many preferences.


i.e. when in doubt by a set of each from Lace Mine 29 - Big Bicycle Wheels


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## mikesee (Aug 25, 2003)

bdundee said:


> i.e. when in doubt by a set of each from Lace Mine 29 - Big Bicycle Wheels


Doing so will also cure cancer.


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## PHeller (Dec 28, 2012)

bdundee said:


> i.e. when in doubt by a set of each from Lace Mine 29 - Big Bicycle Wheels


I wouldn't be asking this question if I had that kind of money. I'd be out riding my multiple wheelsets!


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## Steel Calf (Feb 5, 2010)

PHeller said:


> If we convert 2.6" to mm, we get *66mm, divide that by 25mm (my current rim width) and we get a tire-to-rim-ratio (TTRR) of 2.64.* The tire is roughly 2.64 times wider than the rim.
> 
> So, we can extrapolate that and say something like a *3.8 tire on a 35mm rim is TTRR of 2.74.* Not that much worse.
> 
> While running a 3.8" tires on a 35mm rim wouldn't be ideal, *the industry has long been running 2.3 tires (58mm) on 20mm internal rims, resulting in a TTRR of 2.9!* We're already quite accustomed to big tires on little rims.


Your math of a linear growth relationship between tire width and rim width only works out if assuming that wider tires scale in every way "bigger", e.g. more volume + thicker casting. However in reality plus tires do have a significantly higher air volume surrounded by a very thin casting to keep weight increase at an acceptable range. In order to compensate the stiffness disadvantage of thin sidewalls you need an overproportional wider rim to support the tire or it will buckle under heavy loads when cornering hard. 2.4 tires still work ok on 22.5-25mm rims, a 2.6 tire will need at least a 30mm rim and a 3.0 already needs a 45mm rim, so as you can see required rim width grows much more than the actual tire width.

Theoretically you could run a 3.8" on a 35mm rim with higher air pressures to stabilise the casting but it will nullify the grip advantage and lead to a far worse problem: The bigger air volume of the plus tire acts as an undamped airspring due to its thin casting and bounces off obstacles like a basketball. Imagine I double your fork travel but equally turn down rebound damping - how would that work out for you?

Either way I'd get a 35mm wheelset which should be good for 2.5 - 2.8 tires without adding too much weight. Everything above is a failed attempt to outsmart physics and won't stay in the (mass-)market much longer for obvious reasons.


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## phreeky (Sep 25, 2015)

Opinions are like arseholes, but here is mine (opinion):
- 29mm IW rims are super common and good for 2.3-2.6, and I've found 2.8 OK on them too.
- 35mm would therefore step up a bit and prob be 2.5-3.0, however I'm not sure 2.3s would be too nice on them
- All of them have an element of uncertainty, and keep in mind that plenty of Maxxis 2.3s will measure at 2.2" and Schwalbe 2.3s at 2.4".


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## PHeller (Dec 28, 2012)

Funny, 

I was just reading that American Classic Smokin Gun 40mm internal rims are were designed with 2.5-3.0 tires in mind. 

I could probably be really happy with the variety of high-volume, low weight 2.4-2.5 tires on the market, as long as they'd fit my narrow chainstays with 40mm rims. Err, this would be on my big travel Meta, which would rarely be equipped with such a wheel. 

Currently I've got a Specialized Slaughter 2.6 on 25mm internal rims that's about as big as I can go. I've run a worn Breakout 2.5 on the same rim and it's a hair smaller. I'd probably need to stick with 2.4's if I was going to run them on 40mm rims, which means I'll need some heavily reinforced rear tires.

The 40mm rims would spend most of their lives on my new hardtail which I think would be good fun 3.25" Crux or 3.5" Hodag.


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## Just J (Feb 14, 2005)

I don’t really have any mathematics to back this up, only real world testing done mainly on my Waltworks Ultimate Warrior. 

I run 3.8” Hodags on 45mm rims and find them to work nicely. True width is a smidge over 3.6” on those rims. I could go wider of course but for the time I use this setup my Arc 45 wheels are more than up to it. 

When I built my first 29+ wheels I used 35mm rims (Arc 35) and they were fine with Chupacabra but I now use 45mm LB rims and the profile is much squarer and the tyres just work better in all instances. 

I run 2.4 and 2.5WT tyres on 28mm Reynolds rims on my Pivot and really like them but I’ve also used them on my 30mm LB’s and 35mm wide Arc 35 rims where they are obviously only very slightly wider. 

2.6 Schwalbes work very nicely on 36mm Ibis 741’s and I have also used 2.25” Bontrager SE4 tyres on those rims with success although the SE4’s are much wider than advertised. 

Hope this helps a little bit.


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## prj71 (Dec 29, 2014)

I'm trying a 2.8 rekon on a 50mm width rim right now. So far I like it and see no downside yet. 

Sent from my SM-G900V using Tapatalk


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## 202cycle (Dec 6, 2006)

mikesee said:


> The answer is always going to be "It depends". And the dependencies are your height/weight/riding style, your preferences, your past, present, and future hang-ups, the types of trails you ride, the trail/soil/snow conditions, preferred tire pressures (actual vs. measured), casing construction, and, of course, angle of the dangle.
> 
> "The industry" hasn't sorted this out, and truthfully won't. Too many options, too many people, too many preferences.


This my friends is THE answer. Obviously there will be combinations that are physically impossible, but everything in between depends on all those factors. There's a sweet spot for everyone.


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## wjphillips (Oct 13, 2008)

Well, there have always been some "rules of thumb" to follow on this. 

It's always been said that your tire width should not exceed 2x your rim width. For example, 19mm rim = max tire width of 38mm, etc...

Conversely, the tire width should never be smaller than your rim width. On a road bike, for example, a 23mm road slick should never be mounted to, say, a 25mm rim. Just common sense...

But ya, in a lot of cases (as is true with almost all the tire questions) the answer is going to be it depends. (see above).


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## Guest (Oct 26, 2017)

Depends, yup got me some, and Depending on the day's ride, it shall dictate size and weight......of course that Depends.


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## xblitzkriegx (Jul 29, 2016)

rim to tire width ratios for plus tires

3.0 tire on i50: 1.52
3.0 tire on i45: 1.68
3.0 tire on i40: 1.90
2.8 tire on i50: 1.42
2.8 tire on i45: 1.57
2.8 tire on i40: 1.77
2.8 tire on i35: 2.02
2.6 tire on i45: 1.46
2.6 tire on i40: 1.65
2.6 tire on i35: 1.88
2.6 tire on i30: 2.20

For comparison, here are common rim widths for normal tires:

2.4 tire on i30: 2.03
2.4 tire on i28: 2.17
2.4 tire on i25: 2.44
2.3 tire on i30: 1.93
2.3 tire on i28: 2.17
2.3 tire on i25: 2.44

keep in mind that plus tires have more air volume compared to regular tires. doing a straight comparison to regular tire ratios, a 3" tire should be on an i40, a 2.8" on an i35, and a 2.6 on an i30. imo, those should be minimums, and maximums will be dictated by tire design. imo, id add 5mm to each rim width for each tire and call that ideal. ie, 3" = i45, 2.8 = i40, 2.6 = i35.


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## wilson1417 (Mar 25, 2009)

Maybe a better thread for this feedback...

Been riding 27.5+ 45i Scrapers with various WTB 3.0 tires.
Getting ready to build a new Wheelset and am torn between two rims.

WTB 45i Scrapers
DT Swiss 40i XM551

Love some thoughts from anyone who's ridden both or ridden 40i rims with 3.0 tires.
thanks


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## Rusk (Nov 9, 2009)

wilson1417 said:


> Maybe a better thread for this feedback...
> 
> Been riding 27.5+ 45i Scrapers with various WTB 3.0 tires.
> Getting ready to build a new Wheelset and am torn between two rims.
> ...


I am looking at the same two rims. Which way did you end up going?


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## IAMTHRILL (Jul 25, 2017)

*Barnetts Manual for rim measuring*

This should help clear things up :thumbsup:

Determine size of new tire by one or all of
following choices:
[ ] Look on sidewall of tire or molded in edge of
tread for nominal size description. Enter
here: __________
[ ] Look on sidewall of tire or molded in edge of
tread for ISO size description. Enter here:________

38. [ ] Measure width from bead-to-bead (edge-toedge)
of tire (flattened as best possible) and
record width here: __________
Flattened width between beads
Cross -section of flattened tire
19.22 Flatten the tire and measure bead-to-bead to determine
flattened width.
39. [ ] Divide answer in step 38 by 2.5 to determine
"section width" and record answer
here: __________
40. [ ] Multiply rim inside width from step 37 by 1.4
to determine narrowest acceptable "section
width" and record answer here: __________
41. [ ] Multiply rim inside width from step 37 by
2.0 (road bikes) or 3.0 (MTBs) to determine
widest acceptable "section width" and
record answer here: __________
42. Check one of following choices:
[ ] Step 39 is included in range of steps 40 and
41, so tire width is ideal for rim.
[ ] Step 39 is outside of range of steps 40 and
41, so tire width is potentially unacceptable
for rim.


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## PHeller (Dec 28, 2012)

Apparently Jeff Jones was experimenting with higher volume 2.4 tires on 50mm rims back in 2013 and still likes that setup today.

I think if I ended up building a new wheelset out of some old hubs that I've got, I'd probably go 45 or 50 rim width to be able to comfortably run a 3.8 tire, and still have the ability to run a 2.6 as well. 

After this weekend's bikepacking trip and getting beat up on my hardtail, lower pressures would be nice.

I think 2.6 is as small I like going anymore (nearly all "small" 275 tires have been cleared out of my garage.) 

I figure if I need a long-distance fast rolling setup I'll switch to my 29x2.4 Ardents.


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## lpt1 (Sep 16, 2009)

IAMTHRILL, its so complicated, just to say that inner rim width should be in range 20..29% relative to flattened tire width, or 13..29% for MTB.
IMHO, that MTB special case is not more than legacy error, inherited from manufacturing process of first-gen thin MTB rims based on road rims.

PHeller, simple geometry equation has a result, that any given tire has its maximum overall diameter when tire to rim ratio TTRR=1.38 (so small!), and this point seems to be an optimal ratio, simply by the purpose of pneumotire. At least, for round slick tires, when its shape is not depend on TTRR.
So, i45 rim may be ideal (and widest possible) for 2.4 - 2.5 tire and acceptable (but far from ideal) for 3.8 tire.
My preference is i58 for 3.0 WTB Rangers, for example.
But for knobbies all goes differently. See manufacturer specs, to avoid square or folded-in-half profile of tire tread.


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## Osco (Apr 4, 2013)

xblitzkriegx said:


> rim to tire width ratios for plus tires
> 
> 3.0 tire on i50: 1.52
> 3.0 tire on i45: 1.68
> ...


I'd slim this down and edit a bit to :

3.8 tire on i50: 
3.25 tire on i50: 
3.25 tire on i45:
3.0 tire on i40: 
2.8 tire on i40: 1.77
2.8 tire on i35: 2.02
2.6 tire on i35: 1.88
2.6 tire on i30: 2.20

But that's just me


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## xblitzkriegx (Jul 29, 2016)

theres no reason to slim it down as its meant as a comparison, not an opinion. i agree with your opinion (even though i run i45s with a 3" tire) but i wanted ppl to see for themselves and make thier own decisions.


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## Guest (Jan 9, 2018)

xblitzkriegx said:


> theres no reason to slim it down as its meant as a comparison, not an opinion. i agree with your opinion (even though i run i45s with a 3" tire) but i wanted ppl to see for themselves and make thier own decisions.


me likey your listing for general fitment purposes. :thumbsup:


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## richj8990 (Apr 4, 2017)

wjphillips said:


> Well, there have always been some "rules of thumb" to follow on this.
> 
> It's always been said that your tire width should not exceed 2x your rim width. For example, 19mm rim = max tire width of 38mm, etc...
> 
> ...


Are you talking external or internal rim width???

19mm internal rim width is standard on 559 or 26" rims. Standard 26 x 1.95 inch tire width is 49.5 mm. 49.5/19 = 2.6 tire to rim ratio. The standard is between 2.0 to 3.0x tire to rim width. Am I missing something?

https://www.bikerumor.com/2016/08/12/tech-story-match-bicycle-tire-width-rim-width-best-results/

Is this story wrong? They are saying it's worse to go under 2x tire to rim width than it is to go over 3x tire to rim width.









There is no consensus on what the optimal rim width is on 2.5 inch wide tire or greater. But for 1.1 inch to 2.4 inch tires, it's accepted that they all can fit on a 19mm internal width rim on the chart above. 28/19 minimum is 1.5x tire to rim ratio, and 62/19 is 3.3x max recommended tire to rim ratio. Average is 2.4x. There are people on here that have gone 3.5x and say they have zero problems. According to the article:

"It is primarily based on experience, testing, and feedback from our customers as well as the professional athletes we work with. The basics are that if you run a rim that is too wide for a particular tire you have a lot more issues with tire and rim damage, as the rim is much more likely to bottom out on lateral rock impacts causing tire or rim damage. Conversely, if the tire is too wide for a given rim, you get more tire roll due to the larger casing size and higher aspect ratio of the tire, which together create more leverage on the tire allowing the casing to collapse and roll over the rim during hard cornering."

I am just a dumb beginner, but to me the above translates as too wide is the lesser of the two evils compared with too narrow. And just my opinion but a wide + tire that's two pounds with thick sidewalls should do just fine on a relatively narrow rim. I'm doing 27.5 x 2.5 on a 23 mm internal width rim (2.8x ratio) and it's fine, it's actually great. I've crashed once in 8 months with this front tire. Thin sidewall tires are thin width to begin with so there is no issue. Wider tire = thick sidewall = still OK for cornering because the wall will not collapse like a thin walled tire might. It all balances out.


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## Steel Calf (Feb 5, 2010)

richj8990 said:


> Is this story wrong? They are saying it's worse to go under 2x tire to rim width than it is to go over 3x tire to rim width.
> 
> View attachment 1186916
> 
> ...


An optimal tire to rim ratio across all tires widths is the wrong paradigm here. In fact the wider the tire gets the more rim to tire width converges to a 1:1 ratio (look at fat bikes and cars)

The reason for this is that sidewall thickness doesn't scale up with tire width, wider tires often get thinner sidewalls because otherwise weight would explode but in order to compensate for that loss in stiffness they need increased sidewall support in form of overproportional wide rims, however that only works to a certain extent, from my own experience I'd draw the line at 2.8 tire width with 40mm rims.


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## richj8990 (Apr 4, 2017)

Steel Calf said:


> An optimal tire to rim ratio across all tires widths is the wrong paradigm here. In fact the wider the tire gets the more rim to tire width converges to a 1:1 ratio (look at fat bikes and cars)
> 
> The reason for this is that sidewall thickness doesn't scale up with tire width, wider tires often get thinner sidewalls because otherwise weight would explode but in order to compensate for that loss in stiffness they need increased sidewall support in form of overproportional wide rims, however that only works to a certain extent, from my own experience I'd draw the line at 2.8 tire width with 40mm rims.


OK, that's an interesting point, and yes I've seen the fat bike rims and they are really wide. So I assume for 2.8 you'd recommend 35 or 40mm (2.0x or 1.8x). There was a guy in a different thread that put a 2.8 tire on a 45mm rim (1.6x tire to rim), took pictures, it looked really wrong. All of the sidewall knobs were pointed up. There were no sidewall knobs anymore. He was complaining that the knobs wore out twice as fast as normal with the wider rim; do you think the tire pressure is wrong, and if so is it pumped up too much or too little? Sometimes bike stuff is the opposite of car stuff, as in if you inflate a car tire a lot towards the max pressure limit, it preserves tread life, but for his bike the picture looks like the tire is inflated too much and shortened the tread life. It can't be right if the side knobs are forced up to the top with the center knobs. So for + tires between 2.6 and 3.0 inches wide, maybe a 1.8x tire to rim is the lower limit like you say (at least the example of 2.8)? This is what I was trying to get at earlier, too wide a rim may have more problems than too narrow for + tires compared with true fat tires.

I'm going to try 2.8 on a 21mm rim on the front at first, 3.4x tire to rim (I can't go more than 2.25 or so on the back, the bike is pretty small, so just front only). If the 2.8 is too floppy on that narrow rim, I can buy a 30c rim, spokes, front hub and have the LBS do the wheelbuild for $60, under $150 total parts and labor. That would take the ratio down from 3.4x to 2.4x, seems a lot better. You probably would recommend 35 or 40 rim width but I'll try 30 first, it's not an expensive experiment. That's also a lot cheaper than having to buy a wheelset for $400+. If someone is doing the front only as + due to clearance issues in the back, it seems like buying the rim by itself and then choosing the front hub is way cheaper than these + wheelset current prices. Will let you know how it goes either way.


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## Steel Calf (Feb 5, 2010)

I just recently bought a decent 32spoke boost oem wheelset with WTB Scrapper 40mm rims for 120€ from on-one bikes UK.

A second wheel (or wheelset) has the huge advantage of quickly swapping between tire widths fast, I consider 30mm rim good for 2.6" maximum width, if you want 2.8" a 35mm rim is perfect.


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## Fastskiguy (Jan 15, 2004)

richj8990 said:


> I'm going to try 2.8 on a 21mm rim on the front at first, 3.4x tire to rim ....... Will let you know how it goes either way.


Please do, I'm dying to hear some real world "I rode it and found......" vs. all of the conjecture. Thanks dude, you're doing the community a service


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## mikesee (Aug 25, 2003)

Fastskiguy said:


> Please do, I'm dying to hear some real world "I rode it and found......" vs. all of the conjecture.


Lots of people here *have* ridden them this way. Not a lot to talk about. You have to run the pressure higher to keep the tire from squirming or outright peeling off the rim. How high? Depends on you, your trails, your skill, your perceptions.


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## Fastskiguy (Jan 15, 2004)

mikesee said:


> Lots of people here *have* ridden them this way. Not a lot to talk about. You have to run the pressure higher to keep the tire from squirming or outright peeling off the rim. How high? Depends on you, your trails, your skill, your perceptions.


What size and pressure did you run?


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## mikesee (Aug 25, 2003)

Fastskiguy said:


> What size and pressure did you run?


The list is long. Generally, 3" tires on as small as i29 rims. 3.8" tires on as small as i44 rims. Pressures in the high single digits to high teens.

Never saw any benefit to going narrower on rims than the above. Already too many compromises at that width.


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## mjs1231 (Jan 4, 2013)

The new WT trail standard is 35 mm ID 

that seems to be perfect for the new Maxxis line of WT wide tire standard


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## PHeller (Dec 28, 2012)

I think I'd be more interested to know about the number of people who have encountered problems from overly large rims with "normal" tires than running overly large tires on narrow rims. We keep hearing that the sidewall is more exposed on an overly large rim, but would those tires still have torn on narrower rims? Who knows.

For instance, many folks have had really good luck with Schwalbe 2.6 tires on rims as wide as 40mm, and of course Jeff Jones loved the Ardent 2.4 on 50mm rims (which seems like a bit much). 

I guess it depends on the type of tire, too. Schwalbe's Nobby Nic and Rocket Ron are both very round casings. The Ardent is also pretty round. The DHR, Slaughter, Rock Razor, Trailblazer, even to some extent the Rekon aren't as round. 

I'm still stuck in this dilemma of "do I compromise the future potential to run 3.8 tires on 35/40/45mm rims for the ability to run the 2.6 tires I've got in the garage?"

Stan's even lists the i38 "Major" rim for tires from 3" to 3.5" which might cover the majority of 275x3.8 tires out there. Alternatively, Schwalbe designed the 2.6 tires for use on i30-i40mm rims.


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## Fastskiguy (Jan 15, 2004)

mikesee said:


> The list is long. Generally, 3" tires on as small as i29 rims. 3.8" tires on as small as i44 rims. Pressures in the high single digits to high teens.


So it looks like there are plenty of options out there, thanks!


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## richj8990 (Apr 4, 2017)

PHeller said:


> I think I'd be more interested to know about the number of people who have encountered problems from overly large rims with "normal" tires than running overly large tires on narrow rims. We keep hearing that the sidewall is more exposed on an overly large rim, but would those tires still have torn on narrower rims? Who knows.


EXACTLY!!! You could in theory put a four inch wide fat bike tire on a 45mm rim. This is why no one out there has a concrete, factual + rim size chart yet. We are in uncharted waters between standard and fat bike rims right now, and probably will be for 1-3 more years before anecdotal data becomes real data.

One of these years when I get out of debt (don't ask, small business), I'll get the 'correct' rims that are around 50% of the tire's width, tubeless ready, 450g each, and all that other nice stuff for $500+/wheelset. For now, being a cheap ass by necessity and not choice, I found some interesting 23mm and 24mm internal wheelsets for under $200 that should fit plus tires OK. Wheelmaster makes some with Weinmann, DT Swiss, Alex, etc. rims for a decent price and in theory they should do just fine with a 2.8 or 3.0 tire. I found them on Amazon and other sites typing in keywords 559x24, but they have 584 and 622 as well (more actually than 559). Be careful choosing them though, the cheaper ones are often rim brake only and bolt-on instead of QR. Cheapest wheelset with disk and QR start around $125 and are narrow 19mm or 21mm; another $50 or so for 23/24mm. 25mm and above skyrockets in price for a ready-made wheelset unless you build the wheel from the rim.

2.8 = 71mm tire width / 24mm rim width = 3.0x tire to rim width.

Right now I'm doing a standard tire on a narrow rim: 2.4 = 61 mm tire width / 21 mm rim width = 2.9x tire to rim width, almost exactly the same as above.

And while I have to admit the 2.9x tire and rim ratio feels a tad floppy, they do just fine, and are a huge improvement over the skinnier front tire. I dunno how far you can extrapolate out from 2.4 inches, but $170 for a wheelset is a lot cheaper than $500+ for people on a budget that want to have a plus tire on their non-boosted bike. This would just be for the front though, back cannot take a + tire


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## mjs1231 (Jan 4, 2013)

*30 to 35 ID rims are what the industry / riders have settled on*



PHeller said:


> I think I'd be more interested to know about the number of people who have encountered problems from overly large rims with "normal" tires than running overly large tires on narrow rims. We keep hearing that the sidewall is more exposed on an overly large rim, but would those tires still have torn on narrower rims? Who knows.
> 
> For instance, many folks have had really good luck with Schwalbe 2.6 tires on rims as wide as 40mm, and of course Jeff Jones loved the Ardent 2.4 on 50mm rims (which seems like a bit much).
> 
> ...


your not seeing any professional riders running above 2.6in tires whether 26,27.5 or 29.

Why? because the law of diminishing returns.

Now this is for racing. Riding for fun is a bit different. There are a few guys in my club that tried 2.8 - 3 in and said it didn't effect comfort or traction and felt heavier a more bouncy. Think fat bike.

If you really want to understand what going on go take a look at the EWS rider bike checks. These are enduro bikes built to be podium weapons. But it does give you an idea of what's generally the most efficient and what's worked best for the greatest number of riders.

Wide Trail (WT) Design | Maxxis Tires USA

Can you run Maxxis Wide Trail tires on regular rims? - Mtbr.com

Picking The Perfect Enduro Bike: Which wheel size is right for you? - Mtbr.com

https://www.ambmag.com.au/feature/whats-the-best-rim-width-for-mountain-biking-480973


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## PHeller (Dec 28, 2012)

For the purposes of this discussion I'm not interested in racing. You don't talk about 40mm-50mm rims and racing at the same time. Like you said, diminishing returns after 2.6 tires (which Jared Graves is running) and 35mm rims (which I'm sure a few EWS racers are using).

I've got racing wheels, that's more or less taken care of. I don't race anyway, so it doesn't matter to me.

I'm actually looking more along the lines of a wheelset for soft-condition bikepacking. Not snow, not sand, just soft. I think a lightweight bike with 27.5x3.8 tires would be rad for such conditions. On hardpack I think a 29x2.6 setup would be fine. But I don't like building a wheelset for a specific tire (3.8) because I may want to use the same wheelset for a 2.6 or 2.8.


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## iowamtb (May 17, 2014)

phreeky said:


> Opinions are like arseholes, but here is mine (opinion):
> - 29mm IW rims are super common and good for 2.3-2.6, and I've found 2.8 OK on them too.
> - 35mm would therefore step up a bit and prob be 2.5-3.0, however I'm not sure 2.3s would be too nice on them
> - All of them have an element of uncertainty, and keep in mind that plenty of Maxxis 2.3s will measure at 2.2" and Schwalbe 2.3s at 2.4".


I've had the same question in my head lately. For the last few years I have been running Stans arch EX rims with an i19 with Maxxis ardent 2.4s. I ran those for a couple years and never burped once and never had a problem tubeless. In fact two years ago in Colorado I had to drop my psi down to 7 front and back in order to ride the trail around Leadville without sinking through the snow.

Last winter I built a new set of wheels using the same hubs. I bumped up to Stans Flow ztr with i29. I will say the 2.4 looks so much better on this rim. Now my question is how big of a tire can I go with these new wheels. Stans recommends up to 2.8 so I'll go with that even though I haven't tried it yet.


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## noose (Feb 11, 2004)

wilson1417 said:


> Maybe a better thread for this feedback...
> 
> Been riding 27.5+ 45i Scrapers with various WTB 3.0 tires.
> Getting ready to build a new Wheelset and am torn between two rims.
> ...


I am riding 3.0 Specialized Pergatory grid's on xm551. Great combo for AZ desert riding!


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## Herbert Harris (Feb 18, 2017)

I know that this is an older thread, but I've been comparing i40 vs i35 rims for 2.8 tires for a new wheel set I will be building. While there are some nice charts provided by various rim manufacturers as well as diverse opinions (from super narrow rims recommended by Stans to wide rims recommended by Derby to uber wide rims recommended by Jones), ultimately I think that in this day and age the tire manufacturers should provide for each tire the "IDEAL RIM WIDTH" specification. Teravail is now doing this to their credit and the results are very interesting! For example, 

Coronado: 29 x 2.8 - ideal rim width is i35. 
Coronado: 27.5 x 3.0 - ideal rim width is i45. 
Cumberland: 29 x 2.6 - ideal rim width is i29.
Cumberland: 27.5 x 2.8 - ideal rim width is i45.

This is valuable! And in the comments Teravail says that you can go down or up one notch from there which seems to be a good rule of thumb.

To some extent Maxxis is doing this with their WT tires where they specify i30 to i35 for the ideal rim widths as well as some other companies.

But I think tire manufactures should agree to add the IDEAL RIM WIDTH specification for each tire offering on their websites. This would really help us average peons like myself sort out the muddled waters of tire - rim combinations in these exciting times full of experimentation.


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## mikesee (Aug 25, 2003)

richj8990 said:


> 19mm internal rim width is standard on 559 or 26" rims.


I know this is sort of out of context, but these days I'd argue that the most common width on 26"/559mm rims is 78 to 80mm.


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## eb1888 (Jan 27, 2012)

Herbert Harris said:


> I know that this is an older thread, but I've been comparing i40 vs i35 rims for 2.8 tires for a new wheel set I will be building. While there are some nice charts provided by various rim manufacturers as well as diverse opinions (from super narrow rims recommended by Stans to wide rims recommended by Derby to uber wide rims recommended by Jones), ultimately I think that in this day and age the tire manufacturers should provide for each tire the "IDEAL RIM WIDTH" specification. Teravail is now doing this to their credit and the results are very interesting! For example,
> 
> Coronado: 29 x 2.8 - ideal rim width is i35.
> Coronado: 27.5 x 3.0 - ideal rim width is i45.
> ...


Best rim width isn't absolute unfortunately. If you ride high speeds park terrain, rocky or shale terrain or like big jumps less rim width can be better for that terrain than if you are trail riding loose over hard at medium speeds with limited jumps. At the lower speeds you'll also be able to run lower pressures for a bigger cornering footprint.
If your terrain allows lighter sidewalls where you don't worry much about sidewall slashes you can really benefit from low smaller knob tires at low pressures on wider rims.


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## slowride454 (Jan 11, 2014)

I guess I'm old school. I don't like really wide rims compared to tire size.

I had a fatbike with 26x4.0 on 100s. I hated the tire profile. On my current Farley, I like the 4.6-4.8s on Mulefut 85s. 

My XC bike has WTB KOM i23s with 2.35 wide tires.

I have a 29er converted to 27.5+ and I don't particularly like the tire profile with 27.5 x 2.8 on WTB i45 Scraper rims.

For 29x3.0 I have a wheel set with WTB Frequency i25 and another that with Velocity P35 i30.8 and really like the tire profile compared to an i45 or i50 rim.


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## Bullfrog123 (Mar 21, 2018)

The answer for rim width vs tire width is not that simple...there are too many variables to have a single conversion factor for everything from 2.4 to 3.8.

For example, the aspect ratio of the tires is different i.e. height to width ratio of the actual tire. So measuring across the tire with it flattened out doesn't tell you how the tire was designed.

I have a 3.0 Maxxis High Roller on a 52mm (internal width) rim and the rim is too wide IMO. I also have a Maxxis FBR 3.8 mounted on a 35mm (internal width) rim and the rim is too narrow. That is about the only thing I can tell you for sure .

I did talk to some guys at Maxxis and they like to run their 2.8 tires on a 35i rim even though the Maxxis web site has the info below...if the format gets screwed up the chart is at the bottom of the page on each Maxxis Mountain Bike tire:

Inteded Use	Tire Width (in)	Inner Rim Width (mm)
XC Racing 2.00 - 2.20 20 - 25
Light Trail 2.20 - 2.40 25 - 30
AM/Enduro	2.30 - 2.50 28 - 35
2.60 35 - 40
Plus 2.80 - 3.00 40 - 45
Fat 3.80 - 4.00 70 - 80
4.80 90 - 100


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## Jil (Jan 21, 2018)

Hi !
Quick update on this subject.
Is there a rim inner width that will suit correctly 3.0 to 3.8" tires ? 45mm ?
Other question : is there any reason why I shoudn’t mount a 27.5*3.8 tire with boost wheels (110mm front, 148mm rear) ? I mean, with a specific bespoke frame.
The idea is to find a setup in 27.5 wheels where I could shift from plus format (3.0“ tires) to (alsmost) fat format (3.8“ tires), with the same wheels.


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## BansheeRune (Nov 27, 2011)

Jil said:


> Hi !
> Quick update on this subject.
> Is there a rim inner width that will suit correctly 3.0 to 3.8" tires ? 45mm ?
> Other question : is there any reason why I shoudn’t mount a 27.5*3.8 tire with boost wheels (110mm front, 148mm rear) ? I mean, with a specific bespoke frame.
> The idea is to find a setup in 27.5 wheels where I could shift from plus format (3.0“ tires) to (alsmost) fat format (3.8“ tires), with the same wheels.


I would say, the size range you are looking at would be ideal on i45's. When I bought my Sergeant V3, I opted for 70mm (i64) Alex Blizzerk 27.5's since my plan is to run 3.25-4.0 full time. The idea of i64 was tire profile for traction and flotation in adverse conditions. Rides like a plus bike even when I let the air out! Currently, I am running a pair of Crux 3.25's which do a great job of backcountry exploration. Winter, the Van Helga 4.0's go into service.










Sarge III sportin i64's and 3.8's.


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## mikesee (Aug 25, 2003)

Jil said:


> Hi !
> Quick update on this subject.
> Is there a rim inner width that will suit correctly 3.0 to 3.8" tires ? 45mm ?
> Other question : is there any reason why I shoudn’t mount a 27.5*3.8 tire with boost wheels (110mm front, 148mm rear) ? I mean, with a specific bespoke frame.
> The idea is to find a setup in 27.5 wheels where I could shift from plus format (3.0“ tires) to (alsmost) fat format (3.8“ tires), with the same wheels.



What was the update?

Yes, 45mm can work for both 3.0 and 3.8". It is a compromise.

You may have difficulty finding a frame that is Boost rear and that can fit 27.5 x 3.8".


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## Jil (Jan 21, 2018)

Thanks Bansheerune and mikesee !

@mikesee : the idea would be to build a bespoke frame.
And indeed, ut’s not an update, it’s more that I would like to get updated advices on this subject 
When you say that an inner width of 45mm is a compromise, do you mean that it works well on this whole range (2.8-3.8“), or it’s not a real fit for 3.8“ ? Should I go to i50 ?


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## mikesee (Aug 25, 2003)

There is an enormous difference in air volume going from a 3.0 to a 3.8.

If you choose one rim width to run both tire sizes, it is going to be a compromise somewhere.

You need to be OK with that compromise.


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## NWA_Tre (Sep 30, 2021)

The hard thing about using one rim for two tires of such disparate widths is tire profile. You run a flatter profile on the smaller width and rounder on the larger. Air pressure can help, but tire roll starts to play in as well. If you were talking 3.0 to 3.4 or something...not as big of a disparity...


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## eb1888 (Jan 27, 2012)

The compromise is you won't be able to get all the performance out of the 3.8 on some trails at low to medium speeds. You can't drop the pressure to get the largest footprint possible. It would wallow. So you'll need more pressure to keep the tire sidewall from folding enough to allow the other side to contact the trail surface. No traction from a sidewall. Very fast loss of traction and wipeout. With more width both sides wrinkle with the tread still in contact. If you lose grip it's slower and you can change things to recover.
Speed and trail conditions impact what pressure will work with what tire and rim width. Higher speeds require more pressure and rim width isn't as useful.


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## Captain_America1976 (Mar 15, 2005)

I ran 3.0 tires on a 36id rim for a long time with no issues. I also used to run 3.8 on 42id rims. Both bikes were hardtails.


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## matt4x4 (Dec 21, 2013)

I do not like 4.0 tires and I had 3.50 tires once and it was still a little to big for what I rode, but I never rode what they were intended for, I guess its like having a jacked up truck with big mudder tires on it and never going offroad into deep mud holes but I sure liked the extra air and the 5-10% of the time I rode river rock, river beds. But the other 95% of the time it was just ashphalt and concrete with easy dirt trails.

I need to test out 2.40-3.00 tires and reading about Jeff Jones on 50mm rims I will look into that as I need a new setup.


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## NWA_Tre (Sep 30, 2021)

I’ve got 34mm internal rims and really want to run 2.8’s but don’t want a round balloon profile. Our trails are very natural, loose rock, hard rock slabs, and dirt. I’ve wondered if running the lower air pressures would flatten the tire out, but as of now I’m running 2.5 and 2.6 tires.


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## NWA_Tre (Sep 30, 2021)

NWA_Tre said:


> I’ve got 34mm internal rims and really want to run 2.8’s but don’t want a round balloon profile. Our trails are very natural, loose rock, hard rock slabs, and dirt. I’ve wondered if running the lower air pressures would flatten the tire out, but as of now I’m running 2.5 and 2.6 tires.


Bump. Anyone have experience doing this, on what type of terrain and what riding style?


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## elcapitan29 (Mar 12, 2021)

I am experimenting now with going back from 27.5 plus to semi plus 29s 2.6 and 2.8. My bike has a very low BB, so not an issue. 27.5 plus tires early on needed wide rims because they has such thin sidewalls. The tires have become more stout (especially the Surly tires I now run), but traditional 2.2-2.4 tires have always had stiffer sidewalls, that provide a different feel on narrow rims. The original I29 wheelset on 3.0 tires was a joke. I run I49 on 3.0 and love it.
New 29 wheel is i35 and 2.6 tire. I am trying 2.8 next. I would have gone i40, but there just was not an affordable wheelset that I could find for an experiment.


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## NWA_Tre (Sep 30, 2021)

I’m running 2.6 on front with 34mm internal. Loving it and landing flat quite often…it’s holding up very well with no squirm. I may yet try 2.8’s but so far the 2.6 has been a sweet spot


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## marvin rouge (Mar 12, 2013)

Anybody run Mezcals in 2.6” on i45 rims? I’m looking for a faster rolling rear tire, but wondering whether it’s a step too far for i45…


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## jay_paradox (Oct 21, 2020)

marvin rouge said:


> Anybody run Mezcals in 2.6” on i45 rims? I’m looking for a faster rolling rear tire, but wondering whether it’s a step too far for i45…


Think that might be pushing it but I am interested in hearing from others. I know I want to try 2.6 on i40 but am concerned about losing bb height/clearance going from a 2.8...


Sent from my iPhone using Tapatalk


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## mikesee (Aug 25, 2003)

marvin rouge said:


> Anybody run Mezcals in 2.6” on i45 rims? I’m looking for a faster rolling rear tire, but wondering whether it’s a step too far for i45…



I have this combo on the front of my commuter. Installed it as such just because it's what I had and I didn't want to buy a new tire. Looks _really_ square, but still rolls super fast and I can't say I've ever felt self-steer. Use is ~90% paved and dirt road, maybe 10% doubletrack.


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## marvin rouge (Mar 12, 2013)

A best alternative for my i45s would be Vittorio Bombolonis (closer to 2.9, 924gr and good centre line for speed) but these appear to have vanished. No wait, I found one - sold out everywhere but ***. 🧚‍♂️


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