djb

I'd like to get others experience and opinions on rim widths and how rim width really affects tire width for you.
I'll be honest, before I never really paid any attention to rim width, and when I started using Schwalbe Supremes 2" 50mm, on my rims they are about 45mm. No problem, they work and I loved / love using them.

I finally bought some 1.6" 42mm Supremes, and was hoping that they would be close to that width, I figured it would be a good change.
I was very surprised when I put them on my older style mountain bike rims, Mavic 717, outside width of 22 or 23mm, and instead of being 42mm, the tire is measuring at only
36mm.
To me this is a big difference and I'm disappointed because I really do like wider tires now, so the fact that its hardly any wider than the 35mm regular Marathons I have on my commuter was surprising.
some quick photos

djb

I measured my rim width, exterior, and they are 22/23 (black rim surface, disc only
Another bike we have has wider rims , 26mm exterior, and on those rims, a set of 1.5" marathons measure out to nearly 40mm, tires are marked as 559-40
so I figured it must be my smaller rims.
Put the new "42" Supremes on the wider rim (silver braking surface, disc and rim brake) and what do you know, they are still pretty much the same as the other rims, so 37mm.

djb

regular marathon 1.5, marked as 40, and measures 40 on wider Alex Adventurer 2 rim (one sold on Trolls, LHT, or used to be anyway)

djb

supremes 1.6/42 mounted on both rims, almost the same actual tire width

djb

I then looked at other older rims I have, late 90s or 2000 Ritchey somethings, same width of 22/23mm exterior, and I have a big 2.5" knobby on it, marked on sidewall as 62-559, and sure enough, it measures out to just over 60, so pretty close

djb

So in the end, it would appear that Supremes seem to narrower than claimed, or at least for me, so I would like to know---are my rims very narrow compared to most of your bikes?
Like I said, it doesnt bother me in the least that the 2" 50mm is 45mm on my bikes, but that the expected 1.6" 42mm is only 36 is a bit of a drag.

I am thinking at some point of getting a new wheelset, so any suggestions of rim widths from any of you using wider tires?
I have read a fair amount that too narrow a rim causes the tire shape to become more of a "lightbulb shape", but I'd like to hear thoughts on this sort of thing--and how or if different rim widths affected your actual tire widths.

Tourist in MSN

Your last question, rim widths for future purchases. My experience is solely based on tires with inner tubes, I am quite ignorant on tubeless tires.

I have favored the table at the bottom of this page for sizing rims to tires.
https://www.sheldonbrown.com/tire-sizing.html

Note that rim inner width, not outer was used in that table.

I think as far as rim manufacturers go, Velocity has very good recommendations for matching rim to tire width. Note the chart at the bottom of their page with tire width suggestions for each of their rims.
https://www.velocityusa.com/tech/rims/

Using those two charts I cited above, I have been very happy with the wheels I have built up for my rando bike, Lynskey touring bike, folding bike, former LHT touring bike, and Thorn Sherpa touring bike. Of all these bikes, the widest tire I use is 50mm on the Sherpa, that rim has an internal width of 21mm.

I have also had a disappointment. In 2013 I built up my heavy duty touring bike, Thorn Nomad. Thorn spoke very highly of the Andra 30, suggested it as the best expedition rim and they had photos of that rim and the Schwalbe 57mm Marathon Extreme tire in their brochure, so I did not bother checking the rim specifications, ordered that rim along with those tires based on their recommendations. To make an extremely long story very short, I went ahead and used those rims, but have been disappointed. On a different thread we recently had the discussion of how I had lack of grip on one of my trips with that rim and 57mm wide Extremes, that was when I wished I could have dropped pressure a bit for better grip, but am hesitant to run low pressure on it. The inner width of the rim is only 19mm and I have found at low pressure a 57mm wide tire lacked stability and handled poorly. Instead of turning this into a rant about their bad recommendation, I will just stop here on that topic.

There seems to be two schools of thought, one is that on fairly wide tires you are ok to use a narrow rim. I am not in that group but I have had some arguments with those proponents. I continue to recommend the two charts I cited at the links above.

djb

first of all, I realize my blah blah is disorganized and as usual, overly long......apologies.

secondly, I realized that I should have done the inner measurements. The day I did all the photos, I had taken off and put on a whole slew of tires, replacing a tube, trying this rim out and that rim out, and realized afterwards that I screwed up and didnt take photos of inner measurements...

* just measured my rims, black Mavic 717, and they are only 17mm inner.....so according to the chart you mentioned, that I added here, I'm past the "safe" limits, but apparently others have safely gone past this, like I can attest to.

Tourist what are the actual widths of your 57mm Extremes on your 19mm inner rims?

re handling that you mentioned, "The inner width of the rim is only 19mm and I have found at low pressure a 57mm wide tire lacked stability and handled poorly." it does make me realize that this is a tricky thing to evaluate, this "feeling" we have with a tire at a given pressure.
I do know with the 2in Supremes, when I'd have the pressures lower for really rough or soft stuff, and then was back on pavement and going either fastish or around corners, I could feel the tire moving around a bit, and it would immediately feel better bumping up the pressure just a bit.

this is pretty standard and normal, and the actual numbers of psi so much depend on rider+bike weight.
I can say though without hesitation that for me, the 2" Supremes at proper pressures on my "too narrow" 17mm inner rims, gave me the best handling bicycle around corners that I've ever ridden, so I actually can't fault running them on this size rim.

I'm certain that I've mentioned this before, but I was able to corner to the point that I was even confident moving my body slightly off the saddle mid corner to get my body weight in and down, like in the motorcycle days. Yes, it was just a small amount, but just to show that I was very confident in how the tires felt (not moving around) with fast cornering and due to the construction of the tire sidewall, the "suspension effect" over bumps and whatnot mid corner was consistently good and linear--ie, not any weird feelings.

I dunno, but if for future rim choices, I think I best stick with something like the Alex Adventurer 2 rims that came stock on my wifes Troll, 21mm inner width. The bike came stock with 2.5" Extraterrestrials, and given that I can't see ever using tires under 1.5", this probably would be a safe bet for many tire options.

Tourist in MSN

My 57mm Extremes are in storage. For riding around home I have Hutchinson Cobra 57mm tires on there now, size 26X2.25 or 57X559. They caliper at 53.6mm. So far have not had a reason to put the Marathon Winters on that bike.

My Lynskey was sitting next to my Nomad, so while calipering, did that too. Both of these tires have been out of production for years, a Hutchinson Globetrotter 37mm width on the rear and Schwalbe Marathon XR on front, also 37mm, one calipered at 35 point something, the other was 36 point something mm on my Dyad rims, manufacturer lists inner width at 18.6mm. Velocity recommends 25 to 38mm.

If the bike manufacturer that built up the Troll has a 21mm inner width and 2.5 inch width tire (probably around 62mm?) and that worked well, then go for it. In this case you have that personal experience that you are happy with that.

My Nomad with the 57mm width tires on the 19mm width rims corners nice and handles nice with higher pressures, so I am not questioning if you can make it work, just is it ideal? I can't buy wider rims that have the CSS braking surface anymore, so I am keeping those rims, at least for now. The rims are now 8 years old, have had lots of riding in abrasive conditions, but the braking surface literally looks like a brand new rim. But they stopped making rims with that braking surface a couple years ago, so I am now out of luck on getting any wider that have that. With everybody shifting to disc, they did not get enough people buying CSS rims anymore to make it worth making more.

I looked at the Velocity rim listing, the Quill is also 21mm wide, Velocity recommends that at 25 to 47mm tire width. So, they are staying pretty close to the Sheldon Brown table. They also list the Aileron which is 20mm wide for that same range of 25 to 47mm.

In looking at the Velocity chart again, I just realized another possible factor. Their rims that are listed as tubeless ready appear to have wider recommended tire size ranges. Maybe they feel that the tubeless ready rims are more likely to have a tire with a really solidly seated bead and give it a wider range?

Regarding your thoughts that a 21mm wide rim would work for a wide range, I was very happy with the 21mm Salsa Gordo on my Thorn Sherpa, I have used that with 40mm Marathons (with Greenguard), 50mm Dureme in front and 50m Extreme in back. But that rim is out of production, so I am not suggesting you buy it.

I know that Cyocommute in the past has suggested that the Sheldon Brown chart was too conservative and could allow wider tires too. Perhaps he will comment, and if he does not, you could private message him for his thoughts on the rim and tire combinations you are considering. He has a lot of mountain bike experience.

And there also is the type of road surface that I had a lack of grip, like the photo below. To get much better grip is hard to say how much better I could have gotten if I had dropped my pressure. That is not an ideal road surface.

djb

thanks Tourist for taking the time to measure stuff.
I realize the big problem with talking about rim this and that is that its a pretty boring topic, I'm sure most of us don't think about it, and to know your rim inner width, you have to take the time to take tires off, and or look up specs.

So it would seem that your various tire width measurements more or less show that it's somewhat common for tires to be a bit narrower than stated, but it seems that the 26" Supremes are just a bit narrower than usual in this regard.
It probably is a slight "keep them lighter" thing going on, given that on my wifes rim, her regular Marathons rated at 40mm are 39mm on her rims, where when I put the Supreme 1.6" rated at 42mm it is only 37.

small differences I know....

your comments did help me realize that the 21mm inner rim size is probably the best bet for a future rim purchase. I'm keen on this just from being able to use 2.5 tires comfortably, and I could probably go up to 2.8" or something given my experience "going past" the recommended widths in general.

and yes, I'll try to get some more info on the real life "going past" recommendations.

your experience with the CSS surface really seems to confirm what I've read about them, about folks on world round trips and the rims staying in great shape.

your comment about tubeless ready rims was interesting. The Alex Adventurer 2 rims from my wifes bike are tubeless ready, and I was very surprised by how hard it was getting tires on and off--I suspect being tubeless ready, they are made with tighter clearances or something? Maybe the rim tape used? who knows...

and finally, yes I remember your photo from Iceland, and I look at that and would have wanted at least 2.5" tires if not more. Seems to me that closer to 3" has been mentioned often as the ideal for inland Iceland riding. The riding I've done on 2.5" certainly makes a huge difference riding over and through stuff like that, and it's exactly this sort of riding that appeals to me and why I figure I should get some wider rims that will handle these size tires better, but still able to use 1.5" ish as the lower end of the scale too.

thanks again.

Tourist in MSN

I try to avoid mixing units on tires, I just talk mm, skip the inch version. My Marathons that I cite as 40mm, those I think were sold as 1.5 width, but I just look at the mm number on the sidewall. I can see where buying a 42mm tire and measuring 37 is a big surprise and cause for consternation.

Take a look at the Velocity cross section diagrams for some of the tubeless ready rims and the non-tubeless rims like the Dyad. The shape of the rim is quite different. And yesterday looking at those cross sections, I decided that I do not want to buy any tubeless ready rims for that reason. I am sticking with tubes and I want to be able to easily change tubes and tires.

Dyad is not tubeless ready, I have those rims on my Lynskey and for an extra dynohub wheel that right now is on my rando bike:



The A23 is Tubeless ready, I can see where it could take some work to unseat the bead to change tubes or tires. Tire levers might not be enough if the tire bead and rim have a tight fit.



The rando board recently had a very long thread on tubeless for road bikes, at:
https://www.bikeforums.net/long-dist...oad-tires.html

I had no desire to get tubeless before I read that, but now I am even more sure that I am sticking with tubes. If I had one bike to ride, then I might change my tune but it sounds like you need to have a few quality hours per year for each tubeless bike you own for maintenance. I have too many bikes and too few flats to make that worth it. I average one flat per year.

My Nomad only takes 57mm (or if you prefer 2.25) tires as the widest. As I mentioned above, I have 53.6mm actual width tires on that bike right now, if they were 57mm there would be minimal clearance to the chainstays. So, that is the max for me. I used to have some tires that were closer to that actual 57mm and the gap at the chainstays was really tight.

And if if I want to ride a bike on an icy day, I am putting Marathon Winters (studs) on both front and rear on my Nomad. And then a few months later, changing back again. Tires with sealant would make that a chore.

I think your analysis suggesting that for you a 21mm rim might be ideal for future purposes is spot on.

djb

I'm so used to putting both inches and mm, as well as kms and miles for you guys that I don't think about anymore....but ya, easier if we just stick to mm.
I say that, but as a typical Canadian, we talk in celcius (I've lost my farenheit) , we do the pounds thing more (I can still barely remember what I weigh in kgs) and I can switch back and forth between kph and mph easily---so go figure eh?

one thing I still havent gotten is psi vs bar, I can't for the life of me remember bar pressure numbers....

interesting about the internal shape of tubleless ready rims. On my wifes rim the other day, I actually chipped a bit of plastic off the edge of a Pedros tire lever, and they are tough sons of beaches. Totally surprised me that.

thanks for the rando discussion read, interesting. I tend to agree with you, a lot of work and methods to keep track of, and like you, I get maybe one flat per year, so it just isnt a big deal at all. Until I ride through deserts or something like your thorn story, I just can't see making the effort at this point, especially with multiple bikes and a crapload of bikes in the family. Could change though.

again, thanks for all the insight.
I realize this must be boring as fricking heck to anyone else.....but I've learned a bunch, which is always fun.

79pmooney

Three things that might have been discussed here but if so I missed them. Tire widths tend to sorta consistent among a brand, but far less so from manufacturer to manufacturer. Case in point. 35c Paselas are far wider than 37c Continental ice tires. (Top Contact or some such name.) I never measured but I took off the Paselas to ride in snow one winter, then switched back.

Rim sidewall strength - too much pressure in large tires put a lot of outward force on the rim sidewall, perhaps more than narrow rims are designed for. So rim manufacturers' recommendations re: larger tires may reflect that. Tourers on heavy bikes and higher pressures to avoid pinch flats might want to take that in consideration.

The tires themselves have different shapes, beads and resistance to blowing off, perhaps being a factor when very wide tires are used on narrow rims. I don't have evidence here. I've used 38c Paselas on a wild descent of 18% on deep small (~1-1/2") stones on pressure so low the tires felt glued to the road when I got back on pavement. More than half the tire height of squish. I think I was riding Velocity Aeros but they might have been Open Pros. I had zero issues but I am only 155 pounds and I was riding light and not touring.

I have been a fan of keeping all my rims narrow (too many wheels and love interchangeability which I do a lot). When tires stay on, which they have so far for me, I love 'em. But the consequences of rolling a sidewall out of a rim on a high speed descent, maybe with a cliff at roadside, could be memorable in a less than good way. (I no longer ride much gravel for a very different reason - my health. NFL-like loose brain syndrome. My made-up term but those linemen would get the concept right away. My fat tire riding now is mostly for a gentle farmers market bike - produce comes home less bruised - and fun in the rare snow.)

djb

Thanks monney, ya it seems there are many factors. I'm a light weight so like with lots of bike stuff, this is a big factor, plus I'm a "ride light" sort of rider too.
As you say about rolling off a rim, this is a bit of a concern for me looking to possible future much wider tires, 2.5 " and over, while still carrying stuff.
but as you say, the variability of rim and tire interactions can vary a lot.

again, all interesting to me and good to get a better personal understanding and knowledge of the whole rim/ tire thing, stuff I've never given much thought to before.

Tourist in MSN

I am an engineer by training, we of course had to learn all of our engineering calculations and formulae in both sets of units. I found it much easier to think in SI units than inches, etc. SI was so much simpler when a 1000 ug was a gram, a 1000 g was a kg, a 1000 kg was a metric tonne. An ounce of water is either an ounce by weight or an ounce by volume, but the two are different. A pound is 16 ounces, 2000 pounds is a short ton.

For home use, I bought a really cheap bathroom weight scale. Most scales like that have a button that you press to switch units. Mine, you have to press the button every time you do a measurement to switch to pounds, that is probably why it was half price. So, I quit pushing the buttons, now I can tell you what I weigh in kg instead.

For pressure, bars are close to but slightly different from kg/cm^2, which I am sure you now are saying ... whhhhhhhhhhaaaaaaaaaatttt?



I am not really sure how many decades old my Silca pump is, but it was beat up when I bought it used in the 70s or 80s. I have a hand written table of conversions taped to it.


That is a good point on manufacturers. My Schwalbe tires appeared to be a bit narrower, but pretty close. My Continental 28s calipered at 25mm. I have heard that continentals are often much narrower than labeled.

Rim strength, you are absolutely correct that a bigger tire would have a lower max pressure before rim damage. My Mavic A719 rims (bought in 2004) had this label:

djb

Re bar vs psi, unlike most of the other examples we've brought up, I don't compare the two ever, so haven't drummed into my old brain bar numbers in the pressures I often use, so lets say 30-100psi.

djb

Some of you may enjoy reading this, a Jan Heine piece on rim width and wider tires

https://www.renehersecycles.com/myth...eed-wide-rims/

Russ Roth

A bar is equal to 15psi, ended up memorizing this trying to get my high compression motor volvo 240 up to 15psi, which despite the wide Z rated tires, still spun the tires in 3rd accelerating down an onramp when the turbo actually put a full bar of pressure it. Made for a good time.

I'm learning this on continental. I've been looking at new frames and one capped out at a 42c which my wife wanted to know what that looked like. The LBS has the Continental AT Ride which is listed as a 700x42. Got it home and noticed the label says "700x(40c) 42c" Not certain what the 40c is meant to indicate, perhaps height. Tossed it on a Sun Inferno 25 rim with an inside width of 20.3 and it really looked small. Quick caliper check showed 37mm width to the tire, not even close to a 42mm. Up side is it does fit the cyclocross bike as long as there's no thick sticky mud, its a decent looking tread for hitting the local XC trails here on the island and it was only 25.00. I'll pick up the match this week though it is not the gravel tire I was hoping for.

I've got another set of Continentals in the basement, some sort of commuter tire that's supposedly a 35mm tire according to the sidewall, I've never measured it since I'm disinclined to use it, but eyeballing it I'd guess it measures more like a 30c if that. With the thick tread, the really stiff sidewalls, the narrow appearance and the weight its like the worst of all worlds. Came on the bike and was replaced immediately with something more comfortable. Actually still sitting on the original wheels which I believe measured 28.5 internal. At least it was properly sized for the gravel bikes it came on.

I do plan to put 29x2.1 mtb tires on my gravel bike rims which measure 20mm internal. Although it isn't recommended on some charts, when I had a 26" mtb I ran 26x2.125 on the veloctiy dyad/aeroheat which is 18.6 internal width and it seemed to work fine. Plenty of mtb rims of the time were that width or at times narrower and they worked and I can't see where it still wouldn't. I can remember putting a wtb tire that was 2.25 on and that being an lightbulb but with the Aileron rim having that extra 1.4mm internal width I can't believe that at 2.0 which would be a 54mm or 2.1 are completely out of the question.

djb

Russ, Yup it would very much appear that its not that uncommon for some tires to be a lot different in real life width vs stated.
I really don't see the issue when we're talking just a bit, but like I said, I am disappointed in the stated 42's being only 36-37. Mainly because I have very much become used to that positives of running over all kinds of surfaces with a wider bit of rubber down. They also weren't inexpensive tires, so there's that also.
I'll have to wait until spring to see how I find riding my Troll with the narrower Supremes, I'm sure it will be fine for most conditions, but there's a good chance that I'll go back to the 2" versions for some riding where I could end up on all kinds of surfaces.
Live and Learn.

As you say, mountain bike rims of the range that we both own, have been used with traditional 2, 2.1, 2.2 inch mtb tires for a long time, with no issues.

Oh, and a 240 spinning in third---fun, talk about a good sleeper eh? (probably was a bit of unweighting going on, but still!)
You don't see many 240's around anymore here, there is one I pass every day in a driveway and it looks great, but our salty roads mean most cars over 20 are pretty rare here. You just see the ones never driven in winter.

Tourist in MSN

Off topic, sorry.

In the mid 1980s, a friend of mine was an auto salesman at a Volvo dealership in Minnesota. Volvo at that time produced police cars for the USA market, but a dealer had to have an order from a police department in hand to order one from Volvo. Then suddenly, Volvo decided to get out of the police car market in USA. The dealership was offered two, which they ordered. When they arrived at the dealership, the friend of mine bought one of them within 24 hours. I have no idea how many years he drove that, but it was a peppy little car, with some unusually large numbers on the speedometer. The other one the dealership received, another dealership within a few days was calling around trying to find one that had not been sold yet, so that went fast. I have no idea if that is the model you are talking about, but it might be, it had that base Volvo look for the mid 80s. Interesting options inside like extra large and bright interior lighting, map lights, more sturdy front seats like you would want for an eight hour shift, etc.

djb

I used to follow the British touring car championship many years ago, BTCC, and I know volvo was in that back in the day, so they had a racing division with lots of experience making Mr and Mrs boring Smith Volvos go very fast indeed.
Police forces have and still use them a lot.

Tourist in MSN

After thinking for a few days about this issue of measured width being less than rated tire width, if I was a tire manufacturer, I would try to make my tires a couple mm less wide than rated to make sure that it would not be too wide if someone put the tire on an unusually wide rim. If a tire is too narrow by a few mm, it really does not harm anything. But if it is a few mm too wide, you could have rubbing at a chain stay or problems with fender stays on some bikes if the owner or mechanic decided to push a bit on the tolerances for clearance.

About a decade ago I bought some tires that I thought would work on my folding bike, but there was some rubbing on the chainstays. The tire had a cyclo-cross type of tread, some small knobs on the side of the tread, those knobs were just a bit too much for the frame clearance.

So, I have run into this issue myself.

djb

quite possibly, and as someone with no knowledge of the manufacturing issues / variants involved, I wonder if this plays a part in being conservative.
It will be interesting to see just how much these tires get wider from riding, or if in fact this sort of thing really does happen , as I've read.

IPassGas

Just switched tires back to Supremes after riding with M+'s in AZ. With Ryde Andra 35 (22 mm inner), the 42-559 Supremes (70 psi) measure at 40 mm. I like the Supremes, but glass does appear to create larger cuts more easily.

djb

interesting, wider a bit than my setups, so maybe the rim width wider than what I have makes a difference--but interesting also that yours are still a bit narrower still (although 1mm on each side is not much really)

re the cuts, for sure compared to a super tough tire there will be a difference, but I've been mightily impressed by how little cuts have been pretty limited on my 2in versions, considering what I've ridden over and the types of roads.
I look at it as the riding characteristics of Supremes to be worth being more attentive to what you run over, and how you run over stuff too, simply because they are so nice to ride on.
I'm really looking forward to spring to try them out. I think I'll mount the 2inchers back on though, and ride with them for a week or so first, to get the feel / speed of them again, and then switch out so I have a fresher comparison.

thanks for checking back with your tires/rim example