650b conversion

[Julien]

I have the opportunity to get an older Marinoni that was converted to a 650b light touring bike. Frame started as a road bike somewhere in the 90’s then at some point was stripped down, attachment points for fenders and rack added, chainstays dimpled - all of which at Marinoni’s, and then powdercoated.
I haven’t seen the bike yet but have no experience with such conversions and am curious what the consensus is here - if any. Is that a pass or worth pursuing? Any negative effects on handling that I should know of? Roads are bad around here so fat tires are good.
Grainy photo from the local ad.

[roydyates]

If the switch to 650B moves your bike from 25 or 28mm tires to 38+ mm tires, then it can really make a nice difference on gravel. The ride on smooth pavement is a little different, but not necessarily worse.

[rowebr]

I converted an old Bianchi to 650B and rode it for years before I passed it on to a friend who needed a bike. It was a fun ride on pavement and gravel, definitely get a set of nice tires like Rene Herse slicks or Panaracer gravel king.

Only downside I can think of is long term availability of rim brake 650b rims, but there’s still plenty out there I think.

[Mike V]

I’m working on a conversation now. I have Raleigh International to be done. I’m still collecting parts. Local builder is going to the work on the frame. Fenders, lights, racks and bags all the fun stuff.

[zzy]

Originally Posted by Julien

I have the opportunity to get an older Marinoni that was converted to a 650b light touring bike. Frame started as a road bike somewhere in the 90’s then at some point was stripped down, attachment points for fenders and rack added, chainstays dimpled - all of which at Marinoni’s, and then powdercoated.
I haven’t seen the bike yet but have no experience with such conversions and am curious what the consensus is here - if any. Is that a pass or worth pursuing? Any negative effects on handling that I should know of? Roads are bad around here so fat tires are good.
Grainy photo from the local ad.

A 650bx42 is similar in diameter to 700x23 so if that's the case, then no. You gain a much smoother ride and better fender clearance.

[palincss]

Originally Posted by zzy

A 650bx42 is similar in diameter to 700x23 so if that's the case, then no. You gain a much smoother ride and better fender clearance.

True, but often 650B conversions can't quite fit a 42mm tire. Typically they will fit 38mm at most, and on some frames only a 28 or 32mm. Those, of course, are still major improvements over 23mm but not the "next level" of going to a 42mm.

[NHAero]

Originally Posted by Mike V

I’m working on a conversation now. I have Raleigh International to be done. Snip

I've never found the International to be a good conversationalist. Now, the Raleigh Pro, that's a bike with a witty turn of phrase! And the Super Course could always hold its own in a back-and-forth.

[Mike V]

Originally Posted by NHAero

I've never found the International to be a good conversationalist. Now, the Raleigh Pro, that's a bike with a witty turn of phrase! And the Super Course could always hold its own in a back-and-forth.

https://www.chapmancycles.com/2021/1...0b-conversion/

[tellyho]

Originally Posted by NHAero

I've never found the International to be a good conversationalist. Now, the Raleigh Pro, that's a bike with a witty turn of phrase! And the Super Course could always hold its own in a back-and-forth.

Gimme a Sports any day. That bike holds up its end of the conversation just fine.

[p nut]

Originally Posted by palincss

True, but often 650B conversions can't quite fit a 42mm tire. Typically they will fit 38mm at most, and on some frames only a 28 or 32mm. Those, of course, are still major improvements over 23mm but not the "next level" of going to a 42mm.

That is true. Although it does say they dimpled the CS so maybe it fits fatter. But the fork? On my old conversions, the fork clearance was the issue for fatter tires.

In my opinion, the main issue with these conversions is the brakes. That extra reach needed really makes for poor performing brakes. But I live in the Rockies so lots of hills here.

[mhespenheide]

Originally Posted by p nut

In my opinion, the main issue with these conversions is the brakes. That extra reach needed really makes for poor performing brakes. But I live in the Rockies so lots of hills here.

Go all-in and add new frame mounts for canti's or centerpull brakes.

[rccardr]

Originally Posted by mhespenheide

Go all-in and add new frame mounts for canti's or centerpull brakes.

That might be true but they better be good ones. Went that route in 2017 but never got the Mafacs to do more than scream while they kinda slowed me down. Same deal with the Dia Compe cantis on the several Voyageurs I’ve owned. If I ever go canti again it will be with something like Paul’s using modern levers.

Moving to a dual pivot caliper (in my case, Tektro branded) with quality later SLR style levers resulted in actual nicely modulated braking performance instead of mere speed attenuation. Yes, there are some tire width and fender limitations.

[Julien]

Ok sounds like conversions are quite popular. The bike is equipped with 40s, not sure if that’s the maximum the frame/fork will take. The bike will be used as a commuter/light touring bike by my partner who doesn’t giant clearance anyway, just enough to smooth out the rough tarmac and the many potholes we have around.
I think the brakes are mafac but I’m not sure yet. I have Paul racers on my own bike and I’m super happy with them. Anyway, I’ll go ahead and check the bike and will keep you all posted!

[mhespenheide]

At the right price and size, I'd definitely be interested. Especially if the work was done by Marinoni themselves.

The "Classic and Vintage" folks over on BikeForums can get super-into them; there's a 40-page thread here:
https://www.bikeforums.net/classic-v...ispreloading=1