agnewton

I am trying to close out a project and I have hit a snag. I have a 78 Motobecane Grand Record with Philippe Professional bars. The Weinmann brake levers have no bands and are bolted directly to the bars and anchored with what appear to be a rivnut-type fastener (picture). One brake lever bolted on just fine. The other lever is not going as smoothly (I can't recall if it came off easily).

The rivnut/ anchor threads appear a bit messed up and I can't thread the brake lever allen bolt all the way on. I have not encountered this method of brake lever fastening before and have some questions about the method and possible solutions. I'd also appreciate any background that the good folks of C&V can provide.

Q1: Is this a "factory" feature? Or is this more of an aftermarket hack by the previous owner. My bikes are the more modest members of the cycling universe and this was new to me. Couldn't find any Philippe Professional bars on eBay with that feature.

Q2: What are the options to add that second brake lever to the handlebar? The obvious one is to put a band on the brake lever and be done with it. Can I re-tap the hole/ clean up the threads? If that won't work (for safety reasons or lack of material), can I replace the rivnut? Not sure how I would go about that, but my priority would be a non-destructive extraction. Is there a YouTube video for that?

Thanks for reading and a have a good weekend.
Aric

Picture:


Is that a Rivnut?

BFisher

I had a set of Pivo bars with the same "feature." They came on my '78 Grand Jubile. My line of thinking was 40+ year old aluminum bars with holes in them - I'll err on the side of caution. I replaced them with some nicer, hole-free SR bars that matched the stem, seatpost, and crankset. Just a personal thing. It would seem that this was fairly common. I've seen references to the riv nut brake mount before with French bars.

You could try and clean the threads on the problem riv nut up with a tap.

agnewton

Thanks for your reply. Based on your experience, it seems that band-less brake levers are a French thing. Good to know. Cleaning them up with a tap is my first choice. Would you know if there is anything French about the threading? I couldn't get the bars out of the stem with the rivnut installed, because it has this lip that makes that bar diameter a bit too big to pass through the clamp. I'll consider removing/ replacing the rivnut if I can't tap it.

Thanks again.

BFisher

I believe it's metric threading, M6 and relatively fine threading. Not sure of the exact size. If you have the bolt you can take it to a hardware store to check the thread size and pitch.

agnewton

Definitely taking the bolt with me to Ace Hardware tomorrow. Getting closer to the goal.
Thanks.

oneclick 

Those are a bad idea.

The hole in bar is a stress riser. Worse because of the way a Rivnut attaches. More extra stress when you are braking hard - and bars breaking then is doubly worse.

Get some Weinmann bands and attach the levers with those, and if you have another set of bars use those; cut the ends off what you have and flip them to make bullhorns.

63rickert

No. Just no.

I am always in favor of keeping bikes as original as possible.

Handlebars never break at hoods. They always break right next to stem. That is where the leverage is and the stem is the big stress riser.

I was one of the idiots who drilled his handlebars in the 80s to get cleanest possible aero cable routing. Later would see Rene Herses, more than one, that had same treatment direct from the builder. This required an in hole and an out hole on each side of bar. The out holes were kinda close to the stem.

It is a risk. A completely unnecessary risk. Don’t do it. Someone at Motobecane was nuts forty some years ago. Fix your bike and ride it safe.

repechage

In the mid 80’s, many customers wanted aero routing. The smoothest path for the cable was to enter the bars. I did my own Cinelli bars, being careful to clean up the holes, I made sure the hole adjacent to the stem was at an angle- also dressed smoothly.
At the lever I reduced the hole diameter to only accept the steel - trimmed the vinyl to stop in the bar. The exit at the stem was big enough to pass the entire casing.

those bars And levers are still on that bike today.

I would not do the mod to an unsleeved bar.

problem was in a crash- things would bend at the hole at the lever- saw that.

Chombi1 

I believe the riv nut mounted levers were part of the feature the Motobecanes had with the "permanent" rubber handlebar wrap they had on some of their bikes back then. Maybe the rubber cover was removed on this bar? .... yes, being so odd, it was kinda "a French thing"......

BFisher

May have only been on certain models? I have two here that came stock with that bar covering. One had traditional lever clamps, and the other had the rivnuts.

Other than the obvious issue of the hole drilled in the bars and the nut compressed inside that hole, it complicates repositioning of the levers, and as the op stated, makes stem removal unnecessarily difficult. If I came across another bike with bars like that I would replace them again. Plenty of bars out there, but only one of me.

agnewton

Thanks for your replies and advice one and all. I went to the local Ace today and picked up the 6mm- 1.0 tap to clean-up the stripped rivnut. The operation was a success and now I have two brake levers (photo).

I am deeply committed to not spending any more money on this ride. I like the Atax "Professional" bars and the NOS pair of un-rived bars on eBay are prohibitively expensive. I have already replaced what I think may have been one other engineering innovation from that year. The Weinmann 605 brakes have this teflon pad that snaps in a hole in the brake arm for smoooth brake arm action. The rear of the front brake arm shows why that was probably a bad idea (second photo). The rear brake has a similar crack beginning to propagate if you look at it just right.

I am bar tape and a chain wax away from being finished. And I am looking forward to the first ride.



Trouble en route!



Hmmm... couldn't file that scratch away.

unworthy1

If you have to have French bars I bet you can find something without "rivnut" mounts that would not break the bank, heck if I have anything FR still in my pile of bars I'd be happy to sell you them at a rock-bottom price, but you could probably find someone else here at C&V that has something: what width bars do you use? At least you could add bands to the Weinmann levers and have some adjust-ability, which you have none of with this set.

dddd

What I especially don't think was a good idea about the riv-nut handlebar is what happens when the bike tips over onto the lever?

Where the former band could slip, maybe even stretch a bit and require re-tightening, the riv-nut and bolt would see very great peak of force and stress in the bolt area, possibly fracturing the bolt or further weakening the handlebar at the riv-nut.

Not such a good idea imo, little wonder that this didn't catch on(?).

The integrated tape and hoods surely saved on labor expense and gave a consistently tidy appearance, but was another relatively poor idea which fortunately wasn't too hard to replace (worn/torn "tape" alone could be cut away leaving the hoods intact).
But to the extent that it helped move bikes off the showroom floor and with possible cost savings, it was a good idea.
Very French regardless, they had a way with molded polymers didn't they?

agnewton

I slept on it and the post-purchase forensics of the bike are becoming a bit more clear as I’ve shared details with all of you. The bunged-up threads on the rivnut were for the left/ front brake lever. The cracked brake arm is for the front brake. The top and down tubes have some stress cracks in the paint and a hint of a bulge in the down and head tubes. All tell-tale signs of a front end impact, but the fork, front rim and hub all appear original and undamaged and the paint is original as well.


I took the bike for a quick test ride after purchase (maybe not the best idea in retrospect) and the frame was straight (no-pulling to either side) and it passed the "no-hands” riding test. I had a frame builder look at the frame and fork and he gave it an OK. I couldn't quite figure out how a collision would stress the frame pretty close to yield but not affect the front wheel and fork. My best guess is an emergency stop, that didn't hit anything, stressed the frame, cracked the brake arm, bung-up the threads in the OEM rivnut, and maybe ejected the rider (?). Whatever force loading was imparted to the bike, the handlebars with the rivnut were not the weak component in that episode. The rivnut looks to be brass. So the threads on the nut gave before the steel brake lever bolt did. This unscientific sample seems to agree with the comments of @63rickert (Handlebars never break at hoods. They always break right next to stem.) Will the next emergency stop work out the same way?


I do appreciate everyone’s concern for my safety and I am aware of the risks associated with this design. And I would definitely choose French bars for a replacement and banded brake levers, too. But with the imperfect frame, I’m still undecided about the long-term fate of the bike. That said, I am trying to keep it econo. An alternate eBay search turned up more reasonably priced bars, but with 25.4mm clamp diameter. The Sheldon Brown site suggests sanding down ISO stems to fit the French standard. Can you do the same with handlebars or are you removing too much material?

agnewton

I'd like the bars to be French because the stem clamp diameter is 25.0 mm. The present bars are 40 cm with a 25.0 mm clamp diameter. Can you sand down an ISO bar (25.4 mm clamp dia.--> 25.0 mm) to fit? Or do you need to find a bar with the 25.0 mm clamp diameter? I would be interested in a pair of French bars. What do you have? The only pair of french bars I have are already on my Peugeot. And then there are these rivnut ones...

Narhay

That sounds exactly like me whenever I work on a French bike. Then something threaded or proprietary falls apart.

Charles Wahl

Just don't come back asking how to move the brake levers to a different position. ;->

unworthy1

I will take a look and let you know. I had a big pile of alloy drop bars but I sold a bunch at the last swap meet in which I sold. I know there were a few FR bars but maybe I came back with one, I will know after the weekend. No, I and you do not want to try sanding down the clamp area to make a larger clamp diameter bar fit 25.0, it might work in theory but would not trust the results to be reliable/safe.

agnewton

To make adjustments, you just rotate the bars about the stem clamp, right? I think for now, I am going to learn to like riding on the ramps.

I wasn't sure about sanding the clamp diameter down to fit. Didn't seem like a good idea with the discussion of where handlebars fail, so I'm glad I asked. Would "expanding" the stem to accommodate the extra 1.25mm of circumference for bars with the 25.4 mm diameter clamp lead to the same unsafe situation but with the stem instead? There are some Atax/ Phillipe "Professionel" bars for sale on eBay from France, but they indicate that the clamp diameter is 25.4 mm. I think I'll enquire just to be sure.

Thanks for checking your stock of handlebars for me. Let me know when you get a chance. Thanks again.

obrentharris 

This is not that uncommon. I was hit by a BMW head-on (very slowly, thank goodness): Wheel and fork were fine, top tube and down tube both bent.
Brent

agnewton

OK. Thank you for sharing Brent. It's good to know that my theory has some weight in real-world experience. Glad you were OK. My experiences with front end collisions are, thankfully, limited (light-duty landscape vehicle; cement truck) and I haven't damaged the bikes involved. The test rides have gone well so far (< 40 miles) and I am discovering all the bolts I didn't get snug enough. I'll post a project summary with photos soon. Thanks again.

unworthy1

I looked for one but could not find any FR brand or dimension drop bars in my current collection, looks like they all got sold at the last swap. I do recall some buyer grabbed an armload and made me an offer so...away they went.

agnewton

unworthy1 Thank you for checking. I am going to keep my eye out for a pair-- for safety's sake. In the meantime, the bars and brake levers have survived the first 50 test miles. Only a stripped front derailleur, hi-limit hole remains to be fixed. The engineers on that rivnut/ brake lever design were pretty confident they had dialed in the optimal ergonomic position.

randyjawa 

100% correct. I have had a few of these handlebars come my way, over the years. Though nice and clean looking, even somewhat comfortable, they are, none the less, not my cup of tea. Aside from a too solid way of mounting the lever bodies, one can not ever change out the stem. What was Motobecane thinking...?

agnewton

Were they rubber? The catalog spec says, "soft stiched sleeves". I assumed that meant leather or maybe "pleather". VO had some leather sleeves available last year. Maybe once I get the brake lever position fine-tuned I'll get the leather sleeves .

I still have one loose question that hasn't been resolved in the discussion. So it's bad to sand down the bar clamp diameter (25.4--> 25.0 for French stems); is it also unsafe to "expand" a French stem handlebar clamp to accommodate an ISO bar (i.e. 25.0 --> 25.4mm)?

Thanks.