Univega Nuovo Sport mixte

[Tom]

Okay, so I'm embarking on my first 650b conversion. It's a small (50cm) Univega Nuovo Sport mixte, circa mid-80s in great condition. Very nicely made--Japanese-built chromolly triple-butted frame, "Mangalite" fork, Suntour forged dropouts, "Lawee design" whatever that means,  It's currently got 27" wheels. I've measured the critical dimensions at:

• 46mm tire clearance at chainstays (320mm from axle)
  
• 50mm tire clearance at fork (320 mm from axle)
  
• 50 mm current brake reach + 23mm = 73mm required brake reach both front and rear
  
• 266mm bottom bracket height
  

Seems everything is okay, except maybe the BB might be a little low. It's got 165mm cranks, though, so hopefully that will help, and maybe with the measured tire clearance I could even mount 42mm tires to raise the BB higher. Oddly, it has a recessed brake bolt at the fork, and external brake bolt on the rear. I bought a pair of Weinmann ZAC19 650b rims on the cheap here,  and will order some Sapim spokes in custom length on eBay for about $50 and build up the wheels using the existing Sansin hubs. I've got an old Weinmann 750 centerpull that I might try on the rear wheel, although it seems that I'll want to mount the brake on the "top tube" twin stays and find an extra-long 320mm straddle cable to clear the seat tube. The rear brake cable currently runs through the middle of the "top tube" twin stays. The current rear brake is a sidepull that's mounted on the seat stays and the cable pulls from the bottom. For the front brake--I'm thinking I should find another Weinmann 750 centerpull? Also, I'm not sure if the current ESGE fenders will work well with 650b wheels. 

So, before I go whole-hog into this thing (I've currently ordered just the rims), is there anything I'm completely overlooking here? In theory, it seems like a good 650b conversion candidate, but I've never done this before. I won't be riding it (I'm 6'4"), but it's for my S.O., who's 5'3".

-tom

[Palmer]

Hi Tom,
Sounds like you have it thought through well. I just finished a Schwinn Traveller conversion that turned out great. It was 27” also. Red with red Hetres and 700c sized SKS fenders. Rear brake may need a long straddle cable, this bike had center pulls already and I just swappped the cable from the original brake to the longer reach one as it goes around the seat tube.
Keep us posted on the build.
Tom Palmer
Twin Lake, MI USA

On Tuesday, October 17, 2017 at 1:02:46 AM UTC-4, Tom wrote:
> Okay, so I'm embarking on my first 650b conversion. It's a small (50cm) Univega Nuovo Sport mixte, circa mid-80s in great condition. Very nicely made--Japanese-built chromolly triple-butted frame, "Mangalite" fork, Suntour forged dropouts, "Lawee design" whatever that means,  It's currently got 27" wheels. I've measured the critical dimensions at:
> 46mm tire clearance at chainstays (320mm from axle)
> 50mm tire clearance at fork (320 mm from axle)
> 50 mm current brake reach + 23mm = 73mm required brake reach both front and rear
> 266mm bottom bracket height
>

[Tom Norton]

Tom,
Looking good!
I built up a 1981 Miyata 310 Mixte for my wife last month. Used 650b wheels and a pair of Dia Compe 750's. We did a 4 day ride on the GAP Trail last week and she really likes this bike.
I used components from her Giant Escape hybrid as a temporary fix to see if she was going to like it. Now I am going to start searching for a more " classic" crankset.

[Tom]

Well, mixte conversions appear to be common among us Toms. 

Tom P.--your Schwinn looks grand, and the red Hetres are nice touch. I'm curious what model of brakes you used? For some reason, in the photo they look like something other than Weinmann/Dia-Compe centerpulls. 

Tom N.--those 80s Miyatas are super bikes. I bet it's a nice solid, smooth ride. It's probably similar in many ways to the Univega I'm converting. Good to know that Dia-Compe centerpulls worked on yours! 

-tom

[Palmer]

Tom- The brakes are weinman/dia-comp centerpulls. They were an easy swap, just had to swich out longer armed brakes and the rear straddle cable. I specifically sought out the red Hetres for this and ended up with 2 pair. I have a deep red/maroon Bridgestone RB2 that is getting that pair for a racier build. 

Here is the latest configuration- full front fender and silver rims from a Mirada, Basket and trunk bag. 
Enjoying the step through frames a lot, here is the Mirada dirt tourer/woods bike with 26 x 2.8 tires.

Keep the mixtes coming!

Tom Palmer

Twin Lake, MI USA