I need GB bars in 42-44cm and can’t find them. I do have some 39cm so I am thinking about cutting the bar on each side, just past the engraved part and welding in a stepped, hollow extension. I have the ability to do the machining and welding and can’t really think of a structural reason this would not work. Any comments? Any 42cm GB bars?

I don't think I would. These bars? GB British Randonneur Handlebars 26 0 44cm WIDEST 25 4 Clamp | eBay

Good handlebars are generally made from specially-processed, high-strength alloy. The processing includes the tube drawing and bending processes, plus any post-bending heat-treatment.

Any kind of weld completely interrupts the molecular structure that resulted from the processing, not to mention the alloy composition itself, which would be stratified into zones in and about the weld with varying chemistry and grain structure.

A sleeve might seem to reduce the stress in the area of the weld, but are you taking torsional stress into consideration?

Welding a handlebar made from high-strength alloy withut knowing the exact alloy/chemistry and processing can't be a good idea since there is too much possible weakening of the metal.

For some reason, wide road handlebars were something of a rarity on production bikes in the old days. Some high-end handlebar brands offered wider ones, and builders of high-end bikes sometimes spec'd these bars with widths somewhat in proportion to frame size.

What dddd said. Of course, with enough reinforcement, even a deep pockets company like Walmart has the cajones to saw a handlebar in half and sell it to the public. The thing ain't light, let me tell ya.
For the uninitiated, I'm talking about the drop handlebar modified for twist-grip shifters, on the GMC Denali.

The GB Randonneur handlebars supplied on hundreds of thousands of Schwinn Continental, Super Sport and Sports Tourer models from '71 through '79 were 42cm.

So long as you make it thick enough and allow enough overlap it should be safe and solid, but I think I'd go check out a bike co-op if you have one nearby first.

Did they make them in any size other than 42cm? They're measured center-to-center at the ends, so you'll come up way short if you measure anywhere else, due to the flare.

The old GB bars were made from 2024 T4 material and cold drawn. They were bent in a ball mandrel bender.

2024 alloy, especially in the T4 condition, is extremely difficult to weld, even in an aerospace shop. It requires special solution treatment and then time in a freezer to age it properly. A butt weld, in a thin wall tube is a bad design. If the weld it is subject to torque and bending, the sleeve does little or nothing!

Pip

The things I learn on BF.

Thanks for the suggestion but Randonneurs are not what is wanted.

The old GB bars were made from 2024 T4 material and cold drawn. They were bent in a ball mandrel bender.

Now that is good to know! I am curious as to how you obtained this information. Were 42cm GB's (Maes) even made? What do you think about bonding?

Way back, if one was looking for 42 cm wide bars with a hope of obtaining them, it was Cinelli.
3ttt did make some wide bars.
Ambrosio did too, but inventory was scant.

There was a time where 40 cm ctc bars were considered wide.

Never saw GB Maes bend bars beyond 40 cm, and most were under.

Walmart adapted GripShifters to a road handlebar the easy way, as you said by heavily reinforcing two cut locations around the bars, to allow for some kind of clamping attachment.

The bar first has to be the smaller "mtb" grip diameter, 22mm, instead of the normal 24mm of alloy road bars, in order to accommodate a GripShifter.

The way I did it, starting with a standard 22mm steel road bar with bulged 25.4mm center, I disassembled the GripShifters, then sliced each sleeve part way, to where I had first drilled a stress-relieving hole. I then could slide the sliced inner barrel of each gripshifter along the curves of the steel road bar.
It was a solid setup, and the cable routing was helped by my use of the early 300-series model with straight-down cable exit instead of along the bars. I ended up preferring my shifters elsewhere, at least on my well-fitted bikes that don't have me riding the bar tops most all of the time.

This whole handlebar conundrum extends to the difficulty of sourcing any brand of 42cm bars with 25.4mm clamp size. Only Nitto seems to sell such a bar anymore.

That IS a weird idea.

Bonding the bars to an internal sleeve, you'd have to run calc's on the stress levels, then find an adhesive with the necessary strength and elasticity, and further you would have to assure a constant adhesive thickness, so that the stress levels would stay in check within the elastic range of the metal.
Here again, it's the torsional loading that might really require a very special adhesive in this case, to prevent a typical progressive failure in the bond that that then moves axially along the entire length of the bonded overlap region.
So an over-generous length of overlap is no guarantee of reliability if the bond failure can progress axially due to torsional flexing of the sleeve and handlebar tubing.

And any time that you're using a high-performing adhesive in a highly-stressed application, just as with welding, the process really needs to be developed through the testing phase to assure reliability.

Thanks to all for your replies. I have decided to leave well enough alone and mount the 39cm bars.

The fashion for wider handlebars is pretty recent, and appears to be related to the popularity of mountain bikes. MTB's got a lot of people into biking, which was good; when they switched to road riding, they wanted their road bike to fit like an MTB, which was not necessarily so good.

[MENTION=185430]dddd[/MENTION] - refreshing to read good reasons for not taking shortcuts (just get 'er done, bubba! - no reference to the OP)! Thanks!

How about, "bars were narrow due to many of the racers and racing bikes were developed in southern Europe where people are typically shorter in stature and narrower in the sholders?" Where were drop bars first introduced?

Just try to scrunch up your shoulders. Who needs to expand their rib cages and breathe and all that crap?

I hadn't noticed wider bars helping me to breath better, but can improve/reduce the wrist angle at times, and of course increase the leverage available for steering.

As bike frames evolved toward steeper headtube angles, this geometry enabled steady steering with longer stem extensions. But longer stem extensions are best balanced with wider handlebars in terms of preventing "steering heave" when riding out of the saddle. So newer bikes somewhat tend to favor wider bars at least in part for that reason.
My 1970 Gitane Professional Super Corsa came with <<<34cm-wide>>> handlebars mounted to an 8cm Pivo stem, this on a 59cm frame!!!

For off-road usage, a rider needs to be able to get their weight rearward for descending, and thus very much needs to have brake levers on the top portion of their road bars.
Since the rider's grip is much narrower on this top portion, a wider handlebar allows more leverage by moving the rider's hands further apart.

I've been able to adapt to using older bike's stock, narrow handlebars even while riding off of the saddle, but had to change from a push-pull sort of force (with left and right arms moving oppositely) to more of a left-right application of force (left and right arms now working together) to counter hard pedaling, as when climbing. This method of keeping the bike moving straight ahead while pedaling hard out of the saddle is much easier on stems, so causes no noticeable flex. Again though, the bar width needs to be balanced to stem length.

All bikes require some level of adaptation in terms of rider dynamics, and each rider needs to decide how much adaptation that they can comfortably accommodate, as well as how much twisting force that they want to apply to an old, possibly fragile stem.

Agreed RB.

For me, it's really more about hand real estate though.

I ride distances nowadays and I like to switch hand positions often to reduce fatigue.

Ramps are important as well. Moderate/Long is good and my preference.

[IMG]Untitled by gomango1849, on Flickr[/IMG]

[IMG]Untitled by gomango1849, on Flickr[/IMG]

The only time I deviate is on my cross bike. Still wide, but less ramp.

[IMG]DSCN1373 by gomango1849, on Flickr[/IMG]


My only recommendation on this topic is try different bars/stems till you dial in what works for you and then stick with it. I never liked narrow bars back in the 70s when I was racing and I was thrilled when the wider bars slowly trickled into the market. I had a chance recently to ride a late 70s Super, the bike I used to race. It was set up with 42s and boy, did it feel great.

These bars are for my ’73 Raleigh Pro Mk.IV build and at this point in time originality is more important than fit. We will see how well they work/how much I ride (it).

Once you start riding the bike regularly, you'll quickly get used to the old bars and won't notice they're narrow until after you've returned to riding a different setup again.

That's how it works for me, anyway.

I've been down that road.

Fit/function trumps originality every time for me at this point.

Otherwise they just sit here on a hook.

My wife calls that bike room the museum.

Narrow bars are 'racier' and faster. But if not racing, go with the wide bars. Fortunately, I have a mix of rides and bar set-ups to compare. If on one day I ride a narrow drop and the next switch to a wide, its noticeably more comfortable with the wide, especially on climbs. Breathing is one thing but because of the extra leverage the bike seems to have a more lively yet stable handling while climbing.

Nothing related to a C&V bike but another 'weird' bar set-up. Since this pic was taken, I've done some minor changes but anyhow, its a road drop bar end on flat bar. I use this 700C wheeler as the do-it-all including off-road. I like the ATB controls but is not a good idea if joining the paceline.... at least when not on the drops and it doesn't permit all the other hand positions of the conventional drop. I now have this flat bar cut down / shortened because it was super wide


On a tandem, we switched to the widest rando type for both stoker and capt. It just seems to work well.