Issues with slipping bosco bars?

[jeff perry]

Is anyone else experiencing slipping Bosco bars? No matter how much I tighten the stem, it slips when I apply even a reasonable amount of pressure on the bars. There’s no grease in there to screw things up either. So frustrating because I like the bars, but it’s just not safe to ride this way. I’ve had zero issues on my albatross bars. Anyone else experiencing similar problems?

[Garth]

https://groups.google.com/forum/#!searchin/rbw-owners-bunch/bar$20slip|sort:date/rbw-owners-bunch/-0wcciQEqq0/gzdmgfBvDAAJ

This is applicable. Seems like sufficient torque(with torque wrench of some sort) and/or blue loctite on the bolt threads. Carbon fiber friction paste also. Do measure both the bar and the stem, don't take it for granted they are what they say.

[Clayton.sf]

One of the main reasons 31.8makes more sense. Slips substantially less.

Clayton Scott
HBG, CA

[Garth]

I prefer 2 and 4 bolt open face stems myself, or at least a steel single bolt one. I've never had any of those slip.

[Patrick Moore]

If the stem and clamp area of the bar match as they should, the bar ought not to slip, at least with forces normal to normal riding. Does your stem have a clamp that is sized to the bar? If not, you can shim it; Riv used to sell a shim for this purpose, and you can also cut one from an aluminum can. I've used both sorts.

Loctite or friction paste ought not to be needed for properly matched parts, at least these sorts of parts.

But friction paste does work when bars slip, at least if the gap isn't excessive; My Dahon Hon Solo has a QR clamp that is poorly designed and does not squeeze the bar sufficiently; friction paste works well (as does a retro-fitted all steely steel, internal cam, repurposed Campy seatpost QR in place of the wimpy external-cam original).

On Sat, Oct 12, 2019 at 1:37 PM jeff perry <mail...@gmail.com> wrote:

Is anyone else experiencing slipping Bosco bars?  No matter how much I tighten the stem, it slips when I apply even a reasonable amount of pressure on the bars.  There’s no grease in there to screw things up either.  So frustrating because I like the bars, but it’s just not safe to ride this way.  I’ve had zero issues on my albatross bars. Anyone else experiencing similar problems?

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Patrick Moore

Alburquerque, Nuevo Mexico, Etats Unis d'Amerique

[Patrick Moore]

Forgot to add that a properly made and properly sized, 1-bolt, 25.4 mm or 26.0 mm bar and stem combo won't slip either, in my experience, which is pretty extensive. That is to say, in normal use they will not slip.

One of the main reasons 31.8 makes more sense. Slips substantially less.

I prefer 2 and 4 bolt open face stems myself, or at least a steel single bolt one. I've never had any of those slip.

[Clayton.sf]

When I ride the bike, boscos and Albas and bullhorns and anything else with that kind of lever will slip in a 25.4 or 26 stem if tightened per torque recommended and interfaced properly. Overtorquing and friction paste are ways to minimize this and even that is no guarantee.

Clayton Scott
HBG, CA

[Clayton.sf]

There is a reason bullnoose bars made sense.

Clayton Scott
HbG, CA

[jeff perry]

The stem is a properly matched 25.4 nitto technomic deluxe. I will try the friction paste. Thanks for the tips. If that doesn’t work, I’m going back to albatross.

[Clayton.sf]

The technomic with its steel backing plat will handle a good amount of over torquing. Same with the sleeved boscos. Grease stem bolt and underneath bolt head and apply friction paste.

Cshbgca

[Patrick Moore]

Well, I stand corrected. I've never had a properly set up bar bar slip except for cheap steel bars in cheap steel stems, and even that problem was fixed with a box wrench (ie, it wasn't properly set up).

I guess that yes, the Bullmoose makes sense now.

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[Joe Bernard]

The problem is Nitto tolerances for diameter of clamp and bar can vary just enough to have one not match well with the other. Ask the guy with a slightly oversized Bosco that I recently discovered is pure madness to slide levers and grips on.

[David Bivins]

I switched to bosco moose on my Riv-built Clem for this reason. I'm a big guy, and a couple of times at very sudden stops, I moved the bars in the stem significantly. The integrated stem removes any worry.

On Sat, Oct 12, 2019 at 9:05 PM Joe Bernard <joer...@gmail.com> wrote:

The problem is Nitto tolerances for diameter of clamp and bar can vary just enough to have one not match well with the other. Ask the guy with a slightly oversized Bosco that I recently discovered is pure madness to slide levers and grips on.

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[Patrick Moore]

I thought Nitto had top quality? At their prices, they ought to have.

On Sat, Oct 12, 2019 at 7:05 PM Joe Bernard <joer...@gmail.com> wrote:

The problem is Nitto tolerances for diameter of clamp and bar can vary just enough to have one not match well with the other. Ask the guy with a slightly oversized Bosco that I recently discovered is pure madness to slide levers and grips on.

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[Joe Bernard]

They ought to have, but this isn't the first I've heard of or experienced myself that the diameters can be off just enough to be an issue. But I should reiterate that those Boscos have a LOT of leverage in the design.

[Clayton.sf]

Surprised to hear about this. Never had a single out of spec Nitto item nor have I ever seen one in person and there have been plenty coming through my hands. Only ones I am even aware of are some bars that were stamped with the wrong width.

CSHBGCA

[Joe Bernard]

Speaking of such matters, I was at RBW today and rode a Wolbis with a prototype Bosco Bullmoose that reaches back a bit less and flared a little more. It's perfect, I want one.

[brendonoid]

I had the same problem. Discovered that the bars had slightly deformed at the clamp area and therefore lost the strength of being a tube. 

I could tighten the stem all day but the bar would simply compress and slip with moderate force. Had to throw the bars away. They weren't safe.

To be fair to Grant and Nitto I'm fairly certain that original damage occurred from a poorly fitted shim in a 26 stem. However the shim was only poorly fitted because the bars had slipped at some point.

From an engineering perspective the Bosco is pretty huge lever exerting a lot of force on that clamp area. But I'm not an engineer or particularly good at math so my opinion here is merely opinion.

[Rocky B]

Jeff- Did you purchase your Boscos new or used? From what I remember, the first-ever wave of Boscos had slipping issues with them and Rivendell/Nitto recalled them. I was one of the original purchasers of the handlebar but before I could ever mount them, I had to ship them back for a refund.

Rocky

[dra1980]

I just ordered a set of boscos with the re-stock they did at Walnut Creek and am having the same issues. New stem, new bars, correct sizes but same slip as described here. So you aren't alone. Maybe I'll try that friction paste... is that kind of thing available at any hardware store? 

On Saturday, October 12, 2019 at 3:37:06 PM UTC-4, jeff perry wrote:

[jeff perry]

Sorry to hear that.  I think it’s just poor design, unfortunately.  Too much leverage from the long bars and not enough surface area in the clamp.  The bosco moose seems like the safest way to go.  I’m sticking with my albatross.  I was happy with them anyway, just wanted to try something new. 

Sent from my iPhone

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[John A. Bennett]

I've been riding Bosco bars on my daily commuter (2005 RBW 62cm Saluki) for years, and I have had zero issues with them. 

No slip, no dip. 

They are by far my favorite bars OF ALL TIME, and believe me, I've ridden them all. Well, all of the bars sold by Rivendell, that is. 

https://www.instagram.com/p/B1o6mceBEsf/

John at Rivelo in Portland, Ore. 

[Marc Irwin]

It takes a substantial amount of torque to keep those bars stable.  I was one of the first to try them years ago and they called a few weeks later to see if they were alright.  I had to use a pipe as an extension on my allen wrench to get them tight enough.  They have a freaky long reach back creating a lot of leverage.  I wouldn't trade them for any reason.

Marc

On Saturday, October 12, 2019 at 3:37:06 PM UTC-4, jeff perry wrote:

[Clayton.sf]

Go to a bike shop instead. It is usually sold to install carbon seatposts and bars that are sensitive to over torquing. Often they even have some free samples in which case you can buy tire lever, cable, or tube.

CSHBGCA

[Mark Roland]

I've got two of the non-bull Boscos in service on my 26" tandem. Doesn't see a ton of miles, but no issues.

[jeff perry]

Maybe I just got a defective bar.  Disappointing.  I can’t sell these, so I guess they are an expensive addition to my recycle bin.  

Sent from my iPhone

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[Clayton.sf]

Doubt they are defective. I think it has more to do with how and where a person rides. Some friction paste and judicious overtorquing of stem bolt should mostly solve it.

CSHBGCA

[Bill Lindsay]

From your description, I think you are right not to use them.  If it were me, I would attempt to get my money back from whomever I bought them.  In my case, the only entity from whom I would ever buy a Bosco bar would be Rivendell Bicycle Works, and I'm certain that they would treat me fairly. 

Bill Lindsay

El Cerrito, CA

[Garth]

Without actually measuring anything you have idea what you are working with, either bar or stem.

Even if the bar is slightly out of spec, an open face stem is much more accomodating, the bars don't have to be exact like a single bolt. I've used 25.4 swept back bars in 26.0 open face stems w/o a shim and they didn't budge. 2 and 4 bolt stems usually offer a wider clamp area also.

[Bob B]

I've ridden these bars for many years. When I first installed them they slipped and I found that to fix it I had to tighten the bolt a little bit more than I was comfortable with—once I did, they were set and haven't moved a smidge since.  

[Joe Bernard]

I think the OP has reached the end of his confidence with these bars and just would rather not. Which I totally understand; it's a very important contact between you and the very important front wheel, and you need to know that baby isn't going to move!

[Shawn Granton]

Hello all-

Out of curiosity, does the metal make any difference in slipping? If you had a slipping set, what was it made out of?

Boscos come both in  heat-treated aluminum and chromoly steel. I put a pair of Boscos on my Raleigh Crested Butte four years ago to replace a pair of Civia Duponts. The Duponts were similar, but (probably untreated) aluminum and had quite a bit of "flex" in the bars. I got the Boscos in steel partially because they were cheaper than the aluminum bars, but also because I wanted a less "flexy" feeling. Four years later they're still working good, and I haven't had any slip.

Best,

Shawn in PDX

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[Coal Bee Rye Anne]

I had some cromo Bosco + Nitto old stock cromo riser stem (CT-## {31 or 51, maybe}) slippage. Not much, but a little upon hard out saddle mashing or stopping.

I may or may not have experienced the same with the stock Tallux on my Clem... I can’t recall as I swapped stems fairly quickly as I needed the Tallux long quill length for another build and the Cromo riser with short quill was a perfect substitute at the time.

I later traded the Cromo Bosco finding the 55cm too narrow for my large wingspan (for the bolt upright posture.)

I’ve decided if I try Bosco again I’ll look for the 58cm moose variety, not just to avoid slippage but also a preference for the style (and to complete a bull moose trio.)

Brian Cole
Lawrenceville NJ

[Justin, Oakland]

My Boscos slipped. Overtorqued but no carbon paste. I took them off and replaced them with Chocos.

Which creak.

And drive me nuts. But they are my favorite bar of all time.

[Joe Bernard]

We may just have to admit that putting light wayback bars on light wayforward stems has a practical limit before the laws of physics takes over. Sometimes they creak, sometimes we can push on them hard enough to slip.

[Clayton.sf]

@Justin underneath the bar sleeve there are likely two slits/holes. Squirt some wd40 or t9 in there and the creaking should stop.

CS HBG CA

[Clayton.sf]

I feel like slippage has little to do with bar weight or stem length.
If you want less slip then you need to increase friction between stem and bar. A larger diameter bar/stem interface (31.8mm or 35mm) accomplishes this most elegantly. Friction paste and torque are other means. More exotic solutions are bullmoose style stems (Nitto makes some) that clamp bars in two instead of one area.

Clayton Scott
HBG, CA

[Joe Bernard]

Everything you've described - most of which include a different stem and/or bar design - are intended to combat the physics I'm talking about. My claim stands: I think some people are putting more leverage into the Tallux/Bosco combination than it can withstand without extra remedies at the clamp area. I also think some get lucky with the specific tolerances of their bar/stem and never have a slip.

[Justin August]

Agreed.
I know it won’t happen but a small run of Boscos and Chocos in 31.8 would be awesome.

> On Oct 15, 2019, at 9:13 PM, Joe Bernard <joer...@gmail.com> wrote:
>
> Everything you've described - most of which include a different stem and/or bar design - are intended to combat the physics I'm talking about. My claim stands: I think some people are putting more leverage into the Tallux/Bosco combination than it can withstand without extra remedies at the clamp area. I also think some get lucky with the specific tolerances of their bar/stem and never have a slip.
>

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[Clayton.sf]

Yes, I can dig it.

Clayton Scott
HBG, CA

[jeff perry]

Agreed 100%

Sent from my iPhone

> On Oct 16, 2019, at 12:13 AM, Joe Bernard <joer...@gmail.com> wrote:
>
> Everything you've described - most of which include a different stem and/or bar design - are intended to combat the physics I'm talking about. My claim stands: I think some people are putting more leverage into the Tallux/Bosco combination than it can withstand without extra remedies at the clamp area. I also think some get lucky with the specific tolerances of their bar/stem and never have a slip.
>

[Eric Grim]

I was test fitting Nitto RM016N "Mustache" handlebars to a Nitto "Dirt Drop" stem, and doing so marred the handlebar's clamp area because the stem was just a little too small for a slip fit.  Not much, just a tiny bit, but I thought, "Wait, What?!"

Both the bars and stem were prominently marked 26mm and the bars measured 1.024-inches (26mm=1.0236 inches, a nominal 4 ten-thousandths less than my bars measured).

Oh well, even Nitto has manufacturing tolerances, or they wouldn't also sell stem spreaders.  On the other hand, I need to check out the carbon fiber friction paste others have mentioned, because I have another bar-stem set that slip a little, even though again the numbers match and they should mate.

Trouble with the integrated bar-stem system is that I like to fine-tune the tilt of the bars to suit my (no longer mint condition) wrists.

Eric, Spokane

P.S. Mandatory Rivendell content: these were all for my Appaloosa.

On Saturday, October 12, 2019 at 12:37:06 PM UTC-7, jeff perry wrote:

Is anyone else experiencing slipping Bosco bars? . . . [snip]  Anyone else experiencing similar problems?

[iamkeith]

7:54 am 10/15/19
With my first-run aluminum boscos, I was eventually able to tighten them enough to quit slipping, but I still didn't like how much they flexed/twisted. So I ended up with the steel bullmoose version which are perfect in every way. If I ever try the aluminum ones again, I'll use the nito v4 srem, which might well solve BOTH problems. Seems like this would be a fix for any that have been over-tightened and ovalized, too. But that'll have to be a bike with a threadless steerer. I think Soma, blue lug and ben's all sell them:


https://www.somafabshop.com/shop/product/nitto-stem-v4-2423?category=153

[A. Nostuh]

My aluminum 58cm boscos flex like crazy. They are super light and thin walled tubing. The flex is so much I wonder if they would break but probably just in my head. There is extra comfort from the flex a bit like doing push-ups on a diving board instead of concrete

Al in Saratoga

[jeff perry]

Hey, just wanted to give an update. I applied some carbon seatpost goop in there and miraculously it no longer slips! I was sceptical, but it really works. Thanks to all who gave the tip. As it is, I still prefer my albatross bars, so I will probably be unloading these bars in the near future. Let me know it you’re interested in them. 58cm aluminum version in like-new condition.