A bit if a quandry?

[Tom Norton]

So ere is my situation. A few years ago I bought a 1984 Miyata 610. Rode it for 6 months and decided I really liked it. So I sandblasted it and repainted along with painted and lined lugs. It has been converted to 700c.
BUT, I really want a 650b bike! So I was wondering maybe have the canti posts relocated and then do a repaint.Add the 60b fenders etc.
OR should I just start looking for a actual 650b frame?
Saw the Soma GR and now the Velo Router.
Someone help bring some sanity to my situation!!

[franklyn]

You can borrow a set of 650b wheels and mock it in the frameset first to see how much clearance do you have both in the rear triangle and under the fork crown. If you can run 42mm tires and you really like the frameset very much, then it's worthwhile. If the fork crown has lots of clearance for 650b-42mm tires, you can also consider re-raking the fork so that it will have higher offset (and lower trail).

I like bikes from that era because they use lighter-gauge tubings for a "planing" experience. I have converted a Sequoia and added canti-posts and it's a great bike.

Franklyn

[Reed Kennedy]

For me, it'd come down to how many bikes I've got and whether I'd rather have one more or one fewer.

You're already on the hook for buying a new wheelset. By the time you move the canti posts and reprint you're probably much of the way to the cost of the Velo Routier frame. (Especially if you have a parts box that would help you complete the build.)

The 610 should be pretty comfortable carrying rear loads, whereas the GR and Velo Routier much prefer to carry weight up front. Why not both!

I'll also mention that a GR or VR is a great way to try out for-sure-correct low trail geometry if you're curious about that. You could re-take the 610, but there are compromises involved in doing that.

As for choosing between the GR and the VR, just pick which brakes you want. The center pulls on the VR are my favorite brake ever, so that's the one for me. 

Reed

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[Brad]

The SOMA GR is a pretty mature frame design.  I just acquired the almost last extra fork from SOMA and it has a beautiful French style curve plus all the braze ons I can imagine.

Perhaps you could borrow one?  Always good to have a spare bike around.

Doing a conversion is fun, but even with everything pretty much set it still takes a lot of time.  More if you build your own wheels.

It is the details.  Brakes, lights, fenders, etc.  It is not like a road bike with two sidepull brakes, cable it and go. 

There is a lot to be said for having an experienced builder spec it and a solid marketing company getting it built across the Pacific.

[Philip Kim]

IIRC the 610 only differed from the 1000 by components and geometry, so the tubing is good stuff. f you really like the ride of the 610 a conversion would be nice. A lot of builders can do 650b conversions. Norther Cycles does a pretty bang up job.

I really like a motobecane conversion they recently did. This one has a low trail fork.


I had an 97' trek 531 tubing, and it rode great, but sold it because of clearance issues. Looking back, I would've got a new fork, and had posts added to it for a 650b conversion. It wouldn't have fit 42s with fenders, but 38's with fenders would've been completely fine with me.

[Paul Sherman]

Short answer: buy another frame and convert it.

Detailed answer: if that 610 frame was originally intended for 27" wheels plus fenders, converting to 650b might lower the BB to an annoying degree. IMO it's not worth potentially messing up a bike you already like and have sunk some money into just to try a wheel size you might like.

I'd say shop around for another frameset to do your conversion. Since you're willing to mod/repaint a frame you like, it doesn't even need to be in great cosmetic condition. Something intended for sidepulls will make getting the brake reach you need easier and still leaves the door open for cantis later. Finally, if you're interested in the concept of "planing", a different frame might give a livelier ride. Having owned 3 Miyatas ('81 610, '87? 615GT, '83 912), I've found their tubing to be decidedly sturdy, even on the racing frames. All in all, an excuse to shop for another project frame is always good, right?

Paul
Beijing

[Bill M.]

I have the brochure from '84, the year of my 1000.  Both frames had DB Cr-Mo main tubes.  The 1000 fork is Cr-Mo, the 610 fork is specified as hi-tension.  The 1000 frame had Cr-Mo chainstays and seatstays.  The 610 lists 16 (mm dia) seat stays and oval chainstays without specifying Cr-Mo, so I assume they were hi-tension as well.  

BTW, my 1000 has abysmal fender lines.  The chainstay bridge is way too low IIRC.  Metal fenders just weren't going to work, at least with 700c wheels.  If you start hacking the frame you'll want to check that and see if the bridge needs to be moved.  The head angle is 72 degrees, I don't know whether you'll ever get acceptable 'low-trail' front-load handling.  Mine as stock works well with lowriders, not so well with a front platform rack and trunk.  Rear loading is of course a no-brainer.  Lowering the bottom bracket with the 650b conversion would be very welcome.  I think they used a cast BB intended for a 73 - 74 degree seat tube angle and a normal BB height, but rotated it back to slacken the seat tube leaving the frame with less drop than I'd like.  Makes it hard to get a toe down without fully dismounting from the saddle.

Bill

Stockton, CA

[Brad]

I have a Univega frame with a similarly different bottom bracket.  It seems that for a while certain Japanese makers were making frames where the head tube was 72 and the seat tube was 74.   It would make sense for a short torso population.  A little while later or earlier French racing frames were 74 head angle and 72 seat angle on bigger frames.  My guess is longer torsos, but also a desire for lower flop with short rake forks.  JimG's  trail calculator is quite useful in planning conversions.  http://yojimg.net/bike/web_tools/trailcalc.php
The number I think is important is flop, not trail per se.