klynch92

Sorry if this is a daft question but I'm not sure how to interpret the 16 of this 16-622 printed on the inner-rim of my bike wheel when it's measuring closer to 13-13.5mm with a ruler. The outer rim is closer to 19mm so it can't be that either surely. A browse online didn't offer a clear answer.

I'm asking because I'd like to move from a 25c tyre to a 28c or even a 32c tyre but I'm not sure that's safe here if the inner-rim is in fact in the 13mm range.

Would I be ok regardless (with a new 28c tyre in particular)? Would appreciate any advice. It's a Mavic 192 rim if that's of any help. Thanks

grumpus

That seems odd - I'd expect the difference to be around 6 mm which agrees with your measurement. Maybe they measured below the hook.
I think the 192 was an OEM rim, there's very little information about it online. I use 28 mm tyres on MA40s which are the same width, I don't think I'd go any larger - they wallow in corners when they need a top-up.

70sSanO

You can use 32mm on that rim. Decades ago during the skinny rim era road rims were being rolled to 26” to run on mtbs.

Trek even had their own method to distinguish them; add “Mt” before the model name.

John

Bill Kapaun

As a rule of the thumb. I'll measure the outer and subtract 5mm for an inner.

I'm pretty conservative about using "over wide" tires and I'd use a 32 without qualm on your rim.
Much more than that and I'd start to get qualmy, but like I said........

klynch92

Thanks for the feedback guys, very much appreciated.

I'll include the caveat that I'm changing the tyres because were entering into the real winter weather here now and I'm looking for improved stability more than anything having had a few issues with that recently.

Is there any chance that by putting 32c tyres on the 13-13.5 rim I'll create a lightbulb/balloon effect on the tyre, leading to less traction generally and the tyre maybe rolling as I'm cornering? Or maybe I'm being too cautious. Apologies, I just have no real frame of reference tbh

FBinNY 

If the rim has a hook edge, it MIGHT be that the maker was referencing the inside width, not counting the hook. This would be consistent with ERTRO standards that reference the rim/tire width at the bead.

maddog34

the "16mm" comes from measuring the inner bead seat not the "rim hook".. The difference from outer to inner measurement is the thickness of the braking surface when divided by two. At 1/2mm, the brake tracks will begin to fold and crack.... cheaper rims will fail sooner.

Andrew R Stewart 

Seems to me a simple measurement with a tire removed will provide the real answer.

I have many thousands of miles with labeled 32 tires on MA40 and MA2 rims with no handling or tire fitting issues. Andy Who just rode 31 miles with this combo today)

79pmooney

My winter experience - fat tires on skinny rims work. For those months, I simply don't take sharp corners at criterium speeds. (Most of the time, that's simply asking for trouble, what with water, ice, snow, sand, debris and rotted leaves. I've done many winters with 32c and 35c Paselas on Open Sport and Velocity Aeros. They are a little wider than your rims, but not a lot. At low pressures for ice, the cornering feel is pretty awful but so what? I just accept that this is winter. Soft, squishy tires or steel studs or tires at summer pressures suck for traction. (That flashy summer rubber rules until you hit that sand/leaves/ice where you go down hard.)

Now, I did ride those wheels (or they might have been slightly narrower Open Pros mid summer with 38c and 35c tires front/rear and blasted down a steep, windy gravel road with very low pressure and 1) they did just fine and 2) it was a true blast. (The corners weren't taken at the "edge"; I was riding fix gear and had zero interest in planting a pedal plus the "gravel" was loose 1 1/2: stones. I felt like I had close to the perfect rubber on the bike and that all was right. Yes, had there been hotshots on that ride, they'd have blasted by me at half again my speed and under two thirds my age.)

So. put on the wide rubber. Pump it to decent pressure for roughly the percentage "squish" you use with your narrow tires. Wet or wet leaves? Drop 10-15 pounds. Chance of ice or snow? Drop more. And for each level of low pressure, simply keep your cornering to a level that feels comfortable.

If you want to push the edge in poor conditions, do as cyclocross racers do. Ride tubulars. Very well glued, they do not care how much pressure you have. The CX racers really push the glue bond. I did commuting 25 miles round trip throughout a Boston winter on those tires; sometimes riding a few pump strokes above dead flat on ice. Standard summer glue practices worked just fine and so did the tires. (Rims were trash by March.) But tubulars are a different way of life.

grumpus

He did that already, the between-hook distance was around 13mm, the quoted ETRTO dimension correlates to the below-the-hooks measurement i.e. outer width minus wall thickness of the braking surfaces.
Maybe the wallowing I feel in tight corners (slightly soft 28 mm tyres on MA40) is only noticeable because I'm heavy (250 lb or so)?

Lombard

This is what DT Swiss recommends:

https://pictures.dtswiss.com/uploads...WEB_ZZ_001.pdf

This being said, I have an older mountain bike which came stock with 17mm rims and 2.1 inch tires. I say if your frame can handle 32mm tires, go for it - if you can mount them without too many curse words uttered. You have more to gain using wider tires in winter than anything you will lose in the "lightbulbing" effect.