Rooney 

Please see the first and second posts for both trade options.

I convinced my sister that doing a 650b Motobecane Grand Jubilee conversion would be easy and now I'm paying the price. We found a 23" version, French threaded bb, Reynolds tubing, and Campy dropouts (120mm rear) that's perfect except it's a size too large. I'd love to trade someone for the 21" version. This era is precisely what we need since it has plenty of clearance to run 650x42b. The paint condition isn't crucial as the plan is to get some torch work done before repainting.

Some surface rust in exposed areas, no dents, just years of use.


Saddle is Cardiff







Reynolds remnants



A previous owner's initials? Seems like it should come off with a little solvent and elbow grease.

Rooney 

Also on the table for trade is this later 70's 21" Grand Jubilee. We got this recently thinking it had solved our problems, but there's not really enough clearance for the 650x42b tires at the chainstay bridge (I've been banging my head against a wall all day trying to make various things work on either frameset).

Vitus 172 tubing, English bb, Campy dropouts, also 120mm rear spacing. The paint is in much better condition on this one.

ehcoplex 

How much more clearance do you need for 42’s? Dimpling isn’t too difficult (yeah, yeah, yeah, there are those who will proclaim it results in instant and death….).

Andy_K 

I can't help, per se, but maybe I can offer you some encouragement. I have a Grand Jubilé that started out as your bike's twin before some Gugificazione and 650B conversion.



It's a great platform for what you're doing. Maybe @gugie has something similar in the size you're looking for?

Rooney 

ehcoplex — I'd say the red GJ has 2 to 3mm of clearance on either side of the 42s. Too close for comfort. You can sort of see in the photos I posted that both bikes' chainstays are dimpled. The silver GJ's chainstays have a more significant, indent let's call it, where the chainstay curves around the tire. That's present on the red one too but to a much lesser extent. I'm sure it could be modified, but we'd like to have the bike rideable to get a good idea of the position and set up before doing any mods.

Andy_K — That's a beautiful conversion! I certainly have dreams of sending the future frame out to gugie. We've got a set of Raids I'd love to have brazed on, and my sister is keen to get some water bottle mounts fitted. Who did the paint for yours? It looks like it just rolled out of the factory.

due ruote 

If you have 2-3 mm clearance on either side, that sounds good enough for a test build. Then if it all works out, you could massage a bit more room into the stays.

ehcoplex 

Gotcha. I know 42s have become the 'standard' for 650b conversions, but you might want to give 38s a try. I've got 42s on 2 bikes, and 38s on another. I ride on some pretty rough stuff (seasonal & logging roads, gravel, etc, not to mention just the plain old really crappy 'normal' roads where I live...), and TBH the difference between the 42s and the 38s is practically nil- in fact I'd say the Rene Herse 38s might actually feel a little nicer than the GB Hetres. The other 42s are Soma Grand Randonneur Green label, and they feel a little nicer than the 38s, but just by a hair. If you go the braze-on brakes route, I you could get away with Racers and still have room for fenders with 38s (here's a Brian Chapman Raleigh Int'l 650b conversion with that setup). Sell the Raids for the crazy $$ they go for now and partially finance the new paint job! Anyway, might be worth considering. I think the next 650b I do will be around 38s instead of 42s... And I'm kind of itching to learn how to braze myself now.

Andy_K 

That's powder coat from Groody Bros.

gugie 

@Rooney,

I did what Andy suggested and checked the Atelier inventory, but alas, the only Motobecane Grand Jubilees or Grand Records (similar to GJ) I have are 23-25".

I do however, have a 21" full 531 early 70's Raleigh Super Tourer (similar to the Competition of that era) if you're interested. I'd consider this as a step up from the Motobecanes, which aren't full 531. I've done a few 650b conversions with these, no problems.

PM me if you're interested.

Rooney 

I appreciate you taking the time to check. If it were my call, I'd be inclined to make the Super Tourer work, but my sister loves the Jubilee's lugs and the fact that it's French.

To the other suggestions, I know there are workarounds but this is what we're looking for. She's got another bike to ride in the meantime too.

gugie 

No problem, I'll keep my eyes out for a 21" GJ or GR.

Rooney 

Giving this a gentle weekend nudge