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-   -   A pretty familiar story (650b conversion) (https://www.bikeforums.net/showthread.php?t=1203811)

ctmullins 06-06-20 02:48 PM

A pretty familiar story (650B conversion)
 
Well, itís the end of an era. Iíve decided to convert my Nishiki Prestige to 650B.

This is actually a huge deal. This was my very first good bike, one that I assembled myself back in 1987, when I was in college and becoming enthralled with cycling. I had a copy of Sloaneís book, which I devoured until it literally fell apart. I had a sympathetic LBS, whose owner became accustomed to me coming in about once a month, after saving up enough pennies, to order the next round of parts from his paper catalog. And they were really good parts: mostly SunTour Superbe and Cyclone and Sprint, in keeping with the Japanese origin of the frame. This was my only bike for the next 25 years, during which time it got ridden a lot, then put up for a while as I turned my attention to other interests, then pulled back out and overhauled for another season of riding. Itís a racy frame with racy parts, even though I never raced it, because thatís what was sexy to my young self.

Then I built myself a few more casual rides, eventually ending up with my Trek and my Nishiki mixte. The Prestige hung on the garage wall for many years, looking good but getting no use.

During the Covid lockdown I decided to pull it down again and take it for a spin. And oh my, after riding the Trek with its Jack Browns and the mixte with its Schwalbe Little Big Bens, the Prestige felt harsh and unfriendly!

It turns out that what my twenty-something self found sexy and exciting, my fifty-something self finds jarring and discomfortable.

When I built the Prestige, and for many years afterward, I couldnít conceive of any wheel size other than 700C being on it. But along the way, I stumbled across Sheldonís site, and learned about lots of things, including alternative wheel and tire sizes. And finally the other day my brain, as brains sometimes do, spontaneously assembled a motley collection of disparate ideas, and BOOM! The plan for the 650B metamorphosis became irresistible!

Iíve done the measurements, two and three times, to make sure theyíre right. Iíve pulled a really nice rear hub from my stash, and ordered a front hub and a pair of rims and spokes and brakes. Today I ordered the parts. As and when they arrive, this will come together, and Iíll document it here.

The list of conversion parts:
  • Tektro 559 brakes. A no-brainer.
  • Velocity A23 rims, 32h, black.
  • Sachs New Success rear hub, purchased during one of my C&V parts buying binges here. NOS, 130mm.
  • Sachs 8 speed freewheel, 12 - 24
  • Campy Centaur front hub, NOS, purchased online yesterday (I didnít have a 32h front hub in my stash....)
  • SR Anatomic (Modolo licensed) bars on a MTB stem, from my stash
  • Tektro cross levers and some undecided main brake levers
  • 650B tires undecided, but something around 40mm wide with road tread.
The list of current components that will remain:
  • Suntour Superbe cranks with 42-52 rings
  • MKS Sylvan road quills with no-name half clips
  • Suntour Superbe front mech
  • Suntour Sprint rear mech
  • Suntour Sprint downtube shift levers (all hail Power Ratchet!)
  • A minty new Brooks Cambium C17 Carved
This thread will document the process, and will include many of my prejudices, preferences, and pontifications. And hopefully plenty of photos. Should be fun!

Velo Mule 06-06-20 02:59 PM

Sounds like a good project ctmullins . We are looking forward to some before pictures.

ctmullins 06-06-20 03:31 PM

Indeed! I just snapped the final photo of the old steed in its original (more or less) 700C guise:


https://cimg3.ibsrv.net/gimg/bikefor...26fe4a103.jpeg

noglider 06-06-20 03:47 PM

A worthy bike for conversion. And if you don't like it, you can always switch it back.

Are you sure you want a freewheel? Cassette hubs are nice.

52telecaster 06-06-20 04:06 PM

Cant believe how happy i am with my 912. Youre gonna dig it.
https://cimg1.ibsrv.net/gimg/bikefor...b543339a2f.jpg

ctmullins 06-06-20 04:28 PM


Originally Posted by noglider (Post 21518956)
A worthy bike for conversion. And if you don't like it, you can always switch it back.

Are you sure you want a freewheel? Cassette hubs are nice.

Prejudice number one: I like freewheels.

This is an irrational thing, rooted purely in my familiarity with freewheels, as that was the only option when I started cycling.

Since then, I learned about the technical superiority of Shimano’s FreeHub, with its outboard bearings. Duly noted.

But I’ve never had any problems with bent axles, and I’ve never had any problems with any of my freewheels.

So yeah, for now I’m sticking with my freewheels. :50:

nlerner 06-06-20 05:14 PM

Welcome to the club! I'd say my closest comparison is converting a late 90s Lemond Buenos Aires to 650B x 38mm tires. It took some dimpling of the chainstays, but it converted a lightweight go-fast bike into a cushy, light-weight go-fast bike. I've actually also used it for the extremely hilly D2R2 in western MA as the short wheel base and light weight makes for excellent climbing abilities.

https://live.staticflickr.com/5452/2...87d6ec27_b.jpgLemond1.JPG

52telecaster 06-06-20 07:08 PM


Originally Posted by nlerner (Post 21519112)
Welcome to the club! I'd say my closest comparison is converting a late 90s Lemond Buenos Aires to 650B x 38mm tires. It took some dimpling of the chainstays, but it converted a lightweight go-fast bike into a cushy, light-weight go-fast bike. I've actually also used it for the extremely hilly D2R2 in western MA as the short wheel base and light weight makes for excellent climbing abilities.

https://live.staticflickr.com/5452/2...87d6ec27_b.jpgLemond1.JPG

nice looking ride!

bwilli88 06-07-20 08:02 AM

Sounds like a great plan except the 8 speed freewheel. I have a frame set post 650b gugificatizion
https://cimg5.ibsrv.net/gimg/bikefor...5874d4cb07.jpg
waiting for me in PA when I get there. I hope your conversion goes well.

ctmullins 06-10-20 04:32 PM

Parts are trickling in. First to arrive is a NOS Campagnolo Centaur front hub. It was amazingly affordable from an online retailer, so why not? Anything Campagnolo works for me. It even came in what I assume was the original packaging, with some literature included: a warranty pamphlet, and instructions on how to use the quick release skewer in twelve different languages. :foo: Umm, okay....

http://www.chris-todd.net/images/bikes/650B_0002.JPG

I donít really know anything about Centaur, though. What the heck is going on here? Three sides with flats, and the fourth side with a small hex bolt....?

http://www.chris-todd.net/images/bikes/650B_0001.JPG

Today I also disassembled the Sachs 8-speed freewheel, as it was feeling a bit dry and rough. Following a thread from last year, I was able to put pastorbobnlnh ís advice to good use, and successfully disassembled, cleaned, lubricated, and reassembled the unit. First time ever!

http://www.chris-todd.net/images/bikes/650B_0003.JPG

And hereís the pile, with the NOS Sachs rear hub. Yes, the front hub is gray and the rear hub is silver. I donít really care....

http://www.chris-todd.net/images/bikes/650B_0004.JPG

ctmullins 06-16-20 04:51 PM

I decided to pick up another set of the Tektro RL340 brake levers. I have a pair on the Trek, and they’re really nice for the price. Comfortable, smooth, powerful, classy, and inexpensive. What’s not to love? Plus, having the quick-release on the lever in addition to the quick-release on the caliper should help with fat tire clearance.


https://cimg2.ibsrv.net/gimg/bikefor...fefe0019c2.jpg

Everything I’ve ordered from eBay has arrived quickly, and everything I’ve ordered from retailers is taking forever. Grrrrr.....

ctmullins 06-19-20 12:34 PM

Finally, the rest of the parts! (Well, except for my cross levers....).


https://cimg8.ibsrv.net/gimg/bikefor...93f6dd9c6a.jpg

Rims, spokes, R559 calipers, brake cables, and bar tape.

The day before I’m scheduled to leave town for a week. :notamused:

52telecaster 06-19-20 01:52 PM

What rims are u going with?

52telecaster 06-19-20 01:55 PM

A23s... never mind. Great choice btw.

ctmullins 06-20-20 09:52 AM


Originally Posted by 52telecaster (Post 21542873)
A23s... never mind. Great choice btw.

Thanks! I really don’t know. They seem to have good reviews, and there aren’t too many choices for 650B rims anyway, so there ya go.

I got the front wheel laced, but not tensioned or trued yet. I used Sheldon’s step-by-step, as I have a number of times in the past, with excellent results. This time I’m a little irked though. I expected the valve stem hole to fall between spoke groups, but that didn’t happen.


https://cimg5.ibsrv.net/gimg/bikefor...d7cb061a94.jpg

And I can’t just move the whole pattern over one hole, because the spoke holes are slightly angled towards the hub flanges.

This probably isn’t a big deal, right? Anybody else notice this issue with A23 rims?

Edit: Never mind. I, feeling assured of my ability to lace, completely skipped over Sheldon’s details about the orientation of the second group of spokes. Crap.

52telecaster 06-20-20 10:47 AM


Originally Posted by ctmullins (Post 21544070)
Thanks! I really donít know. They seem to have good reviews, and there arenít too many choices for 650B rims anyway, so there ya go.

I got the front wheel laced, but not tensioned or trued yet. I used Sheldonís step-by-step, as I have a number of times in the past, with excellent results. This time Iím a little irked though. I expected the valve stem hole to fall between spoke groups, but that didnít happen.


https://cimg5.ibsrv.net/gimg/bikefor...d7cb061a94.jpg

And I canít just move the whole pattern over one hole, because the spoke holes are slightly angled towards the hub flanges.

This probably isnít a big deal, right? Anybody else notice this issue with A23 rims?

Edit: Never mind. I, feeling assured of my ability to lace, completely skipped over Sheldonís details about the orientation of the second group of spokes. Crap.

i very often do that when i lace. It doesnt bother me at all. My son has a23s in 700c on a bianchi. Light and strong!

ctmullins 06-20-20 11:58 AM

As is often the case, once the nature of the error has been realized, the fix is fairly quick and straightforward! :rolleyes:

All done.

ctmullins 06-20-20 08:38 PM

Rear wheel laced, and both wheels preliminarily tensioned. Truing will have to wait until my return in a few days.


https://cimg6.ibsrv.net/gimg/bikefor...d0afba9de4.jpg

ctmullins 06-29-20 02:52 PM

On-the-frame truing.


https://cimg8.ibsrv.net/gimg/bikefor...676727a8e4.jpg

650B rims with the old brakes still set for 700C.


https://cimg5.ibsrv.net/gimg/bikefor...c36399fcf5.jpg

Tires should arrive tomorrow!

ctmullins 06-30-20 07:33 PM

Tires arrived today, which were the last of the parts. Thanks to the COVID work-from-home mandate, I was able to do assembly in between conference calls and queries.

The Schwalbe Marathons, having crossed the continent in pretzel form, were a bit recalcitrant about being mounted, and even though they eventually succumbed, they refused to bead-seat themselves exactly correctly. I’m hoping they will slowly acclimate...

The R559 calipers, of course, are fantastic, as are the levers, both pair of them. I’ve never had a set of cross levers before. I think I’m going to like them.

While not necessary for the 650B conversion, I swapped out the bars and stem for a different geometry. At my age I’m more interested in comfort than aerodynamics, so while the bars are the same (Modolo Anatomic), the stem is higher, with less reach.

Anyway, here she is ready for the test ride...


https://cimg9.ibsrv.net/gimg/bikefor...dbb3e85df7.jpg


... which was successful! I was prepared for something to break or fall off, but somehow I managed to put it all together properly. (But no bar tape yet, in case I need to adjust the lever positions.) Even though I had the tires pretty firm (trying to use air pressure to help seat the beads), I quite enjoyed the combination of the same old nimble frame with the luxuriously comfy new shoes.

https://cimg1.ibsrv.net/gimg/bikefor...3b74081ccd.jpg

This is going to be fun!


https://cimg7.ibsrv.net/gimg/bikefor...3b1d381a0e.jpg


https://cimg5.ibsrv.net/gimg/bikefor...498538f71c.jpg

52telecaster 06-30-20 07:51 PM

Excellent! And you inspired me. Built an a23 set in silver 32 hole.
https://cimg3.ibsrv.net/gimg/bikefor...43fa85fc4a.jpg

ctmullins 06-30-20 08:18 PM

Hey cool!

This bike has gone from being the skinniest-tired to the fattest-tired in my modest fleet. So of course I now have plans to turn an old MTB frame into a plus-sized beach cruiser....

ctmullins 07-02-20 09:31 AM

I adjusted the cross levers downwards, to fall more naturally under my fingers. Then I wrapped the bars with Soma charcoal grey cushion tape.


https://cimg4.ibsrv.net/gimg/bikefor...e574bf58d0.jpg

The front tire is well seated, but I’ve been fighting with the back tire. I’ve done quite a bit of overinflating, underinflating, pulling, tugging, massaging, and even some dish soap. It’s better now, but there’s still a bit of a flat spot. I’m hoping it will work itself out over the next 100 miles.

As expected, the fat tires make the whole ride so much smoother. The responsiveness of the frame isn’t changed, but the ride quality has gone from bone-shaking to supple-but-taut. Pressure is around 60 psi right now, which may be a little bit high for my weenie self, we’ll see. :lol:

Now to put some miles on it! :giver:

abshipp 07-02-20 10:09 AM


Originally Posted by ctmullins (Post 21545020)
Rear wheel laced, and both wheels preliminarily tensioned. Truing will have to wait until my return in a few days.

Don't they build up nicely?

This bike looks super fun, kudos!


Originally Posted by 52telecaster (Post 21562772)
Excellent! And you inspired me. Built an a23 set in silver 32 hole.

Must be A23 build week, I finished up a 650b A23 wheelset Tuesday evening :D

Andy_K 07-02-20 11:55 AM


Originally Posted by abshipp (Post 21565385)
Must be A23 build week, I finished up a 650b A23 wheelset Tuesday evening :D

Welcome to the club. We should get T-shirts. ;)

I've got two sets of 650B A23 wheels, one with the standard silver rims and one with polished silver. Trouble is I've only got one 650B bike. Hmm.... What can I do about that?


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