An experiment: going to 650b to allow for fatter tires

[weisan]

So the last couple of days I had been working on getting a slightly bigger tire on my titanium bike. It's built by a candian company called T-Lab, they are based in Montreal. It's what they call their allroad model R3 Omni. I bought it used from the first owner a few months ago. It fits me like.a glove and rides fantastic. I was riding it with gravel tires 37mm WTB riddler up front and 35mm Teravail Cannonball in the rear and surprisingly I have no problem keeping up with our regular group rides in this format, although we are not going that fast, we are a bunch of retirees in our 50-70s, averaging 17-18mph. Some of the roads that we ride on out in the country are really bad, rough, littered with potholes, loose gravel - I just appreciate having fatter and more robust tires that I can ride over them sometimes without worrying about punctures. Plus we are riding for general fitness and "ride to eat", I don't mind working harder riding those tires with greater rolling resistance and burning more calories. So, I was told that if I swap over to a 650b set of wheels, I could go up to 42mm tires. So I wanted to put that theory to the test. I built up a set of 650b wheels on Sunday, started off with a set of 40mm teravail cannonball and lo and behold, it was already rubbing on one side of the chainstays. Apparently, the guys at T-lab pride themselves in being able to create their tubes in crazy shapes supposedly to result in the kind of "vertical compliance, supple ride" magic carpet ride. Well, as you can see in this picture, they have resulted in both sides of the chainstays that are not "equivalent" in distance from the middle so in order to make the rubbing go away, I have to re-dish my rear wheel more towards the left....that's crazy! and it's the first time i have to do that for any frame that I owned. So I did that and tried again, unfortunately, the clearance for a 40m tires is way too tight for comfort, even for someone like me who likes to push the boundaries. I ended up with putting on a Pacenti Pari-motio 38mm in the rear and called it done.

[AngryScientist]

I got to talk with the T-lab crew a little at the last Philly bike show. Cool bikes and they are doing some innovative work with titanium. I forget the details but they had one bike there that belonged to a woman who rode the hell out of it, 10's of thousands of miles. Was cool to see such a well ridden machine.

I dont think they get the recognition that Firefly/Moots/No22 do for some reason.

For me this year, I'm 100% back to skinny tire road. Twenty five C for me. Wide tires certainly have their place, but not every bike needs to be a beach cruiser, at least in my small world.

[Hilltopperny]

The problem with some of the allroad/gravel bikes like your T-Lab is the stays being asymmetrical for clearance that just isn't dimpled enough for a 650b to be effectively larger than the 700c tires you can run. The inner diameter of the rim can come into play as well, but since your calipers are showing very little clearance I would stick to the 700c for this particular bicycle unless you prefer the lower BB and quicker spin up of the 650bs.

T-Lab make a really smooth riding bicycle from my experience with the one I tested out years ago. They are the former Guru titanium crew and I hold the Praemio R I had in the past in very high regard. It was a smooth and fast machine that had me searching for another one recently! It reminds me a bit of a titanium Mxxxxxo!

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[tellyho]

I have that 650x38 setup on a Lemond Zurich where I dimpled the stays. I think 38s are plenty for ugly roads, but not quite enough for aggressive gravel. For me.

[weisan]

Originally Posted by AngryScientist

I got to talk with the T-lab crew a little at the last Philly bike show. Cool bikes and they are doing some innovative work with titanium.

For me this year, I'm 100% back to skinny tire road. Twenty five C for me.

Completely agreed. Like I said, the bike rides wonderfully and seeing what they did with the tubes (flattening and ovalizing) - it's some crazy stuff!

I would go for weeks on the fat tires and then went back to my regular 27mm pure road bikes - the sensation of free speed, it's intoxicating.

Originally Posted by Hilltopperny

The problem with some of the allroad/gravel bikes like your T-Lab is the stays being asymmetrical for clearance that just isn't dimpled enough for a 650b to be effectively larger than the 700c tires you can run.
T-Lab make a really smooth riding bicycle from my experience with the one I tested out years ago. They are the former Guru titanium crew and I hold the Praemio R I had in the past in very high regard. It was a smooth and fast machine that had me searching for another one recently! It reminds me a bit of a titanium Mxxxxxo!

Again, hill pal, this thread is not throwing stones at the T-lab pals, and to be fair, they have never said or promised on their website that the allroad bike can accommodate 650bx42mm tires, all they say was it was optimized up to 700x35mm in terms of clearance.

It's interesting that you can comparing it to a Mxxxxxo. I have yet to own a Peg, hopefully one day I will find one with a paint scheme that I like..

Originally Posted by tellyho

I have that 650x38 setup on a Lemond Zurich where I dimpled the stays. I think 38s are plenty for ugly roads, but not quite enough for aggressive gravel. For me.

tell pal, I agree, 38mm would not be enough for gnarly gravel for me as well...I need at least 48mm and up,

[jamesdak]

Originally Posted by AngryScientist

For me this year, I'm 100% back to skinny tire road. Twenty five C for me. Wide tires certainly have their place, but not every bike needs to be a beach cruiser, at least in my small world.

AMEN!!!!!

Most everything I have run 25C. Every time I've gone beyond 28C on a bike the ride feel/handling feel is just too compromised from what I think a bike should feel like.

[jamesdak]

Sorry this didn't turn out for you like you hoped. My one foray into a 650b conversion was a blast and yielded a cool bike different from my full on road racing bikes. Great for cruising and could actually go plenty fast.

[marciero]

I've also had a recalibration of sorts regarding tire width, for gravel at least, and trending downward when it seems the whole world is trending wider and wider. Everyone points at Unbound. But what works at a muddy Unbound, or even a dry Unbound, has no bearing on the gravel riding I do. I just got some very nice 700c wheels to go on a new bike and I dont want to put heavy, kludgy tires on there.

[Spdntrxi]

going from say 42 (700c) to 47 (650) was not enough to make a difference to me, so I axed this setup and traded G27 for G23s. Not looking back .

[ridethecliche]

Weisan, are you running tubeless?

If you already are then go get more comfort I'd look at contact points. Something like the suspension posts and stems. That would help a bunch. In addition to tubeless of course!

[AngryScientist]

I found the pic I took of that bike at the Philly show.

The set-up may look unconventional, but it definitely works for it's owner for many many miles.

[mhespenheide]

Originally Posted by AngryScientist

For me this year, I'm 100% back to skinny tire road. Twenty five C for me. Wide tires certainly have their place, but not every bike needs to be a beach cruiser, at least in my small world.

I don't know that the "roads" in my area would support that choice, but I'm glad yours are in good condition!

[unterhausen]

New Jerseyites are proud that Old Mine Road had the oldest potholes in the U.S., so I'm not sure it's a great place for small tires. OTOH, they are paving it finally.

I rode a 600km brevet in New Jersey in 2019, and I was impressed at how bad the roads were. Route went through the Pine Barrens and down to the beaches. I probably could have gotten away with 25mm tires, but I would have hated myself. I forget why, but I rode my gravel bike with 40mm slicks.

[ridethecliche]

I want to put the absolute fattest tire I can fit in my TCR without high risk of rubbing (so like 32-33 as measured) because there are some potholed roads out here in philly that are just sketchy as all get out.

I feel more confident on slightly wider tires, especially when descending. Hell, I'd be more comfortable trying to bunny hop over a pothole or raised lip on the road if I wasn't on 23s or 25s. Sure it can be done, but I kinda embrace progress.

I find irony in calling bikes with 32mm tires beach cruisers since wider tires, especially newer ones, have been tested as faster.

Also, I really want a T-Lab now! Maybe for my next gravel bike...someday. Ti seems like a great choice for a long term gravel/groad bike.

[donevwil]

Originally Posted by mhespenheide

I don't know that the "roads" in my area would support that choice, but I'm glad yours are in good condition!

Ha, so true. Welcome to Sonoma County.