Another Tire Size Rant/Warning

[jruhlen1980]

Originally Posted by charliedid

I think that rim is too narrow for a 38mm tire.

TB14s are a fairly wide rim, I forget exactly how wide but that was one reason I bought them. I ran 38s (actually measured out to about 38) on them for a couple years before I wore through the brake track.

[charliedid]

Originally Posted by jruhlen1980

TB14s are a fairly wide rim, I forget exactly how wide but that was one reason I bought them. I ran 38s (actually measured out to about 38) on them for a couple years before I wore through the brake track.

17.5 internal 23 mm external.

I say too narrow to get a good profile.

Some don't or won't care and that's okay too :-)

[mtechnica]

Originally Posted by doomridesout

Products made from rubber... Nothing to be done. Doubt your butt can tell a difference.

hmmmm.......................... Taken out of context this could mean a lot of things.

[mtechnica]

Originally Posted by jambee

@cribbit not just women. People.

As a European I can tell you that the T shirt and jacket sizes in the U.S. are always two numbers bigger for me. I wear M in U.S. and XL in Europe!

Yeah I'm 6' and 165lb and wear size M shirts and jackets in U.S. size. Sketchy. In Costco size I'm a small

[texasbbq]

I have both sizes of Shikoro's you mention.

My 700x38's are mounted onto HED Belgium + rims with tubes and caliper out at 37.3mm

My 700x48's are mounted onto Velocity Cliffhanger rims also with tubes and caliper out at 47.9mm.

Hope this helps.

BTW, both sizes have been awesome for road and gravel and the 48's are on my camping bike that does see light single track. Neither would be great in the mud though.

[cachagua]

Originally Posted by texasbbq

I have both sizes of Shikoro's you mention.

My 700x38's are mounted onto HED Belgium + rims with tubes and caliper out at 37.3mm

My 700x48's are mounted onto Velocity Cliffhanger rims also with tubes and caliper out at 47.9mm.

Hope this helps.

BTW, both sizes have been awesome for road and gravel and the 48's are on my camping bike that does see light single track. Neither would be great in the mud though.

Thank you, that raises some interesting possibilities. I'll try the 38s on the Belgium+ wheels, they might actually work on the bike I want those tires for. As for the bike I'd be taking the B+s off of... well, there's the rub. Might have to figure out something completely different for that bike.

Originally Posted by charliedid

[TB14s are] 17.5 internal 23 mm external... too narrow to get a good profile...

I'm open to suggestions on rims too. If we figure a 28mm tire assumes an acceptable profile on a 17.5mm internal-width rim, then to ride a 48mm tire, I'd want a rim with an internal width of about 30mm, right?

[charliedid]

Originally Posted by cachagua

Thank you, that raises some interesting possibilities. I'll try the 38s on the Belgium+ wheels, they might actually work on the bike I want those tires for. As for the bike I'd be taking the B+s off of... well, there's the rub. Might have to figure out something completely different for that bike.



I'm open to suggestions on rims too. If we figure a 28mm tire assumes an acceptable profile on a 17.5mm internal-width rim, then to ride a 48mm tire, I'd want a rim with an internal width of about 30mm, right?

You're not going to find 30mm but the closer to 20mm (35-45 tire) you get the better ride and profile IMO

For those 48mm as Texasbbq mentioned a Velocity Cliffhanger or maybe a DT-481?

It's a ll a little subjective and just reading tech specs doesn't always get you what you want in a rim and tire combo.

[spoonrobot]

Companies are back playing the size/weight game, this is especially egregious now that wide supple tires are in vogue. Companies have been shipping tires around 5-10% narrower than spec to keep the weight down so I would expect Soma, using the same manufacturer, would be doing the same thing. Oddly enough the actual Panaracer branded tires I've seen have all been almost exactly to spec.

I've ran through a few compass baby shoe pass tires that started at 39.5mm and expanded over 3000 miles to...39.5mm so the supple tire growing with use isn't something that should be relied on.

Also keep in mind that the casing is a fixed dimension and using wider rims to get a wider tire often leads to a much shorter tire. I've got a pair of 38mm gravel king slicks that are great but never quite gave me the performance/comfort I was looking for when mounted on 25mm internal rims. Turns out they were running 40mm wide but only 33mm tall so the pressures I was using were all wrong.

[spoonrobot]

Originally Posted by charliedid

17.5 internal 23 mm external.

I say too narrow to get a good profile.

Some don't or won't care and that's okay too :-)

And yet this was exactly what was spec'd for decades on bikes running 1 3/8" tires (~35mm).

[ColonelJLloyd]

Originally Posted by charliedid

You're not going to find 30mm but the closer to 20mm (35-45 tire) you get the better ride and profile IMO

For those 48mm as Texasbbq mentioned a Velocity Cliffhanger or maybe a DT-481?

It's a ll a little subjective and just reading tech specs doesn't always get you what you want in a rim and tire combo.

Better be careful using rims wider than ~25mm or so. Some rim brakes won't play nice with wider rims if they'll work at all.

I'd say 22.5-26.5mm internal is a sweet spot for a 48mm tire.

In my experience, tires do not measure as wide on TB14s as they do on other 23mm external rims. I attribute this to the TB14s shape, sidewall thickness and particular bead hook shape.

[charliedid]

Originally Posted by spoonrobot

And yet this was exactly what was spec'd for decades on bikes running 1 3/8" tires (~35mm).

Everything older was better ;-)

[charliedid]

Originally Posted by ColonelJLloyd

Better be careful using rims wider than ~25mm or so. Some rim brakes won't play nice with wider rims if they'll work at all.

I'd say 22.5-26.5mm internal is a sweet spot for a 48mm tire.

In my experience, tires do not measure as wide on TB14s as they do on other 23mm external rims. I attribute this to the TB14s shape, sidewall thickness and particular bead hook shape.

I agree?!

[charliedid]

Point being that anyone on a rim that wide is running disc or canti and maybe even the weirdo or two on center pull.

For a road caliper I agree

[ColonelJLloyd]

Originally Posted by charliedid

Point being that anyone on a rim that wide is running disc or canti and maybe even the weirdo or two on center pull.

For a road caliper I agree

Well, it doesn't sound like you do. Cantilevers are the rim brake design most likely to give you trouble with wider rims as the pivot is fixed and the angle at which the pad hits the rim can change significantly with rim width. And all cantilevers are designed with an optimal angle. Thinline pads and the like can allow some fudging, but not much. Just try and install a Velocity Cliffhanger on a bike with cantilevers that wasn't specifically designed around a rim that wide.

[Mark McM]

Originally Posted by ColonelJLloyd

Well, it doesn't sound like you do. Cantilevers are the rim brake design most likely to give you trouble with wider rims as the pivot is fixed and the angle at which the pad hits the rim can change significantly with rim width. And all cantilevers are designed with an optimal angle. Thinline pads and the like can allow some fudging, but not much. Just try and install a Velocity Cliffhanger on a bike with cantilevers that wasn't specifically designed around a rim that wide.

This is one (of several reasons) that Shimano designed their Parallel Push V-brakes, and Avid designed their Arch Rival V-brakes. These brakes keep the pads moving in a nearly straight line to the rim, regardless of rim width: