Ah, pedal strike! Now I understand your point--yeah, that is a critical factor in any 650B conversion. I like the distance between the center of the crank and the ground to be at least 10" and that's too low for some. On that St. Etienne conversion, I need to remember not to pedal through sharp turns, but otherwise it's not a problem. On converting go-fast bikes, they tend to have high BBs in the first place, so it hasn't been a problem to lower that down a bit.

I met Steve at the '15 un-meeting, great guy, we've been following the same path on frame conversion, and have traded emails back and forth a few times since. He created "FREK" decals for that bike. Unfortunately it was stolen a few months ago.

The difference is that he's a lot more hardcore when it comes to riding. He's done PBP and a lot of 300-1000k brevets.

I've only had pedal strike issues on one bike that I converted. I was using it as a commuter. It's being torn down, I'll probably sell the frame.

I'm surprised that you're not giving that bike the "gugie" treatment and brazing some bits and bobs on it to make it better behaved when cornering,

You could probably get 42's on the Trek without fenders. Read carefully about the RB-1, the tires only measure out to 36mm even though they are labeled 38mm. There is no room for 38s without dimpling of the stays.

FYI, the B-Lines are basically a Pasela in 650b. They are made by Panaracer using the same tread pattern and AFAIK, the same casing and tread compound. Nice tires, but not the nicest available, especially for the MSRP. I only got them because I found a super sale one time. I'd get Compass or Grand Bois tires or find some Pacenti Pari Motos on eBay for cheap. The PM tread isn't as thick, but the casing is supple and the ride is sublime.

Well frak! That stinks!

I've heard/read great things about the Compass tires. I'm leaning towards the Panaracer gravel king 650b x 38c tires though; you can pick them up for under $40 which isn't bad.

[MENTION=302603]bikemig[/MENTION],

I have a spare set of 650b Synergy rims laced to 36 hole Phil Wood FSA (130/freewheel) hubs. They don't get any use since I built another set of wheels (650b Pacenti PL23 to 36 hole dynamo front and VO rear cassette).

In fact, the last time they were used was when I loaned them to [MENTION=251447]ThermionicScott[/MENTION] last year, for his 650b fit test.

Anyway, they're located in Cedar Rapids any time you want to borrow them. If you like them, you can make me an offer.

Regarding 650b rims: The Weinmann ZAC19 rims have too-deep wells that tend to capture the tire and prevent the bead from seating easily. Synergy rims have a similar problem, but not to the extreme of the ZAC19s.
Mounting a tire on the ZAC19 rim takes lots of manual wrestling to get the tire bead up out of the valley.
I have two sets of the Uglyrm ZAC19 wheels. They're very inexpensive and the hubs have been reliable, but the mounting frustration lessens their value a bit.

My Pacenti rims seem to be a bit tougher to get the tire onto at first, but once mounted the tire goes right into its proper place up on the bead.

I converted my Rivendell Road Standard to 650b, and I'm very happy with the conversion.

Before: barely fit 700 x 28 tires, no fenders
Now: fits 650 x 38 tires plus fenders

The conversion did lower my bottom bracket almost a full cm, and I can scrape a pedal in a corner if I'm not careful. So, I learned to be careful and it's not a problem (I use a 170 mm crank).
My Riv had a low BB to begin with (80 mm drop), so a frame with less BB drop may not be a problem.

Positive effects of the ultra-low BB:
I can put one foot almost flat on the ground when stopped without getting off my saddle.
The handling feels very stable, seemingly because of the lower center of gravity.

IMG_07731_zpsst3nvqm4.jpg Photo by Tim_Gavin | Photobucket

[MENTION=343977]Tim_Iowa[/MENTION], did you ever try layering the bottom of the rims with cloth rim tape?

In reading the "Rene Herse" book, I learned that they used to deal with tires that had too big a bead by putting a layer of handlebar tape in the rim wells. Showing once again that the French thought of everything first.

Cool beans, I may take you up on this. I also appreciate the advice about the rims. I am leaning towards soma weymouth rims (I like the price at around $50 per rim) but the weight is a bit on the high side at 580 grams. I like velocity rims.

Gugie, thanks for the kind words. It was great hanging out at the un-meeting. But for the record, that was Frek I that was stolen. The bike featured in BQ is the new and improved Frek II. I made some mistakes and learned a lot on the first attempt and as a result the new one is even better. I'm still riding it and I've made a few tweaks since the BQ piece. The most important change is that I dimpled the chainstays so I can comfortably run Compass Babyshoe Pass tires.

Steve

FREKII! That's frekking great!

I find I'm constantly refining my rando conversions. My biggest challenge lately is improving on wire routing, specifically around the fork crown area. I'm not very sold on running wiring through the fender and taping it down, even with the thick adhesive duct tape.

Boulder Bikes is selling the Panaracer Pacenti Pari Motos in 38 and 42mm width for $36/tire.

I kind of feel like this is my first go around with my Trek too. I bought the frame specifically to build up as an allroad-ish bike last year. I don't have things set up permanently, especially the wiring. I want to experiment and be sure it fits well. I've read a few threads on dimpling chainstays, (I think gugie had one too?) but want to be more than 80% sure I want to do something irreversible. I also need to practice on a few scrap frames first.

You can find a set on ebay for less than $60 shipped.

Not sure there's much I can add - I've done one conversion of a 25" Windsor, originally built for 27" wheels. I already had the frame, so was able to measure from the bikeman guide and be fairly certain it'd all work out to some extent. Finding brakes with sufficient reach was the biggest challenge. I wound up needing a Weinmann 900 centerpull on the rear, which wasn't easy to find, but did work well enough. The replacement fork needed a Weinmann 750 centerpull. With the significant difference in clearance above the tire front and rear I decided to not use fenders, though some creative brackets could have gotten fender clearance close front and rear. Not elegant.

What I found from that build was:
It's worth considering front and rear clearance if you want to run fenders, the closer to identical the better. I'd also look for a 700c bike with good clearances over a 27" design. Long chainstays are good. Sizing up a bit (I usually ride ~61cm frames) gave a French fit that was great for the road, but that bike always felt cumbersome on singletrack. Which I suppose it should. Sounds you're more interested in longer paved distances, so maybe size up a touch. Get the bars higher. The first conversion should give an idea of what does and does not work for you. Plan on building a second conversion after some time, maybe build with resale of parts in mind / what to carry over. I found it worth buying a better set of wheels as I was pretty sure I'd transfer them to something at some point. Also start with a gear range target and select drivetrain components to match. That bike fit 38mm (measured) tires, which I found to be enough. Plenty for rough roads. Pedal strike wasn't really an issue on pavement. It happened once, but I was asking for it. Exciting to find the limit, but manageable. Pedal strike was more of an issue on uneven off-road/hiking+MTB trails with roots and rocks.

That's a pretty important thing to add. My Trek has MAFAC Raids at the moment, but Weinmann or Dia Compe 750's would also work. One could modify the frame to accept recessed nut Tektro 559's, but they also make a standard nutted version.

I know, the $$$ start to add up...

So, I posted this in another 650B thread, but thought it might have some value here as well. This custom Pelizzoli frame was designed to work with a bunch of wheel/tire/component combinations, including 700 X 32 and 650B X 38. These 650's were built by Peter Chisholm using a pair of low flange Record hubs I had and Velocity A23's (rear is offset). I can use the Record brakeset with the big 700's but the 650's require Tektro 559's.


Here it is set up with the 650's for this weekend's El Tour de Tucson:





For comparison, a drive side shot with the 32's and the original CLE cable housing, which I found too soft and squishy:

This is a beautiful bike and bike porn is always welcome,

So I like the idea of a bike you can convert from 700 x 32c to 650b x 38 wheels. What is the difference in ride quality between the two different wheel/tire sizes? I take it that the 38c is being run at a lower tire pressure, right?

Why do you think you might want to dimple the chain stays? Aren't you running 650b x 38mm tires without any trouble on your 1979 Trek 710?

This is great advice. Yeah I plan on building wheels that I want to keep. I figure if this bike doesn't work, there's always the next (more expensive) project down the road . . . .

Like you I'm pretty certain my project bike will work based on the Bikeman measurements

Why is it important to have similar clearance between front and rear brakes if running fenders?

Yep, with the 650's I'm running 50 pounds. Am tempted to drop that a little, we'll see. With Rubino Pro III's, I usually run 100. Too soo to tell about ride quality, will know more after this weekend. The real reason behind the 650B's was for vintage events with mixed pavement/gravel, like Cino and L'Eroica. I'll probably use the 700's with 25 Rubino's most of the time on pavement.

To my mind, this really is the key difference. Many (if not most) vintage bikes that you can use for a 650b conversion probably can take a 32c. A 32c is obviously fine for all around use and most gravel roads. But fatter at lower volume is good. I was fence sitting on whether to run 700c or 650b on the 1979 Trek 510 I have sitting on a hook until I read this article by Jan Heine (you've probably seen it):

https://janheine.wordpress.com/2013/...limeters-make/

The difference in tire volume between a 32c and a 38 is pretty impressive; plus you can significantly drop tire pressure which improves your "suspension" system.

Well, it's not a requirement, but could help in getting the fender clearance and fender-line closer to equal front and rear assuming there's enough clearance to begin with. From my pic above you can see that the clearance between the front tire and fork crown is much more limited than the clearance between the rear tire and brake bridge. If fenders were mounted ~directly to the fork crown and brake bridge, the clearance between fender and tire at the rear would have been disproportionately large in comparison to the front. It would have taken a long L-bracket or similar at the brake bridge to get rear fender clearance to match clearance up front. I didn't do that, so I'm not sure how stiff / secure the bracket at the rear / brake bridge would have been. Certainly not an ideal solution, and it also highlights the difference in brake reach front and rear - that being in some part, though not entirely, due to the replacement fork being designed for 700c (a compromise to test low trail).

I'd worry more about brake reach than fender fitment (apart from ensuring there's enough tire-to-fender clearance). I will note that the Weinmann 750 front and 900 rear calipers did offer ~adequate braking power, though strong drummer hands may have been part of that. Improved braking power was one of the key elements to the second conversion.

See next page for abridged version.