Author Topic: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?  (Read 747 times)

I seem to have acquired a set of 1990s (but NOS) 3TTT Ergo Power Due handebars (with "TdF" bend"), as the price was good and the width and reach were what I was looking for, and they're double-grooved for Campagnolo Erogs Ergos, but they're an odd 25.8mm size, whereas the Nitto Pearl stem I want to use with them is for 26mm bars. Will I need to use a shim of some sort with them, or is the difference small enough for this not to be needed? Nitto only seem to do shims for going from 25.4mm to 26mm. If needing a shim, would material from a Coke can work?



Old enough to know better, but young enough to do it anyway

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #1 on: March 13, 2019, 06:59:23 pm »
I'd say you'll need a shim and part of a coke can will be fine.
Bread of heaven, bread of heaven.

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #2 on: March 13, 2019, 08:49:19 pm »
I agree. And I hope your erogs get better, sounds painful, that....

cheers

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #3 on: March 13, 2019, 08:52:01 pm »
I agree. And I hope your erogs get better, sounds painful, that....

LOL! Now corrected.

Are bars that require a shim more likely to make creaking sounds?

Old enough to know better, but young enough to do it anyway

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #4 on: March 13, 2019, 10:13:52 pm »
yes possibly, just because there are more interfaces.  However the shims can be made softer than either stem or bar material (and they will be if made from aluminium can) so can conform better to the mating surfaces.  This may in some circumstances result is less creaking....

cheers

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #5 on: March 13, 2019, 11:41:55 pm »
yes possibly, just because there are more interfaces.  However the shims can be made softer than either stem or bar material (and they will be if made from aluminium can) so can conform better to the mating surfaces.  This may in some circumstances result is less creaking....

Okay, thanks, I may give this a go. Anyone know anything about these bars? Think they're a similar shape to Giro D'Italia 64s, but adapted a bit better for Campagnolo Ergos, with both the shape of the bend and the double cable grooves.
Old enough to know better, but young enough to do it anyway

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #6 on: March 14, 2019, 08:11:52 am »
No shim is necessary.
I have a similar 3ttt handlebar in a 26.0 stem, after 27 years it still fits perfect.

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #7 on: March 14, 2019, 09:16:57 am »
No shim is necessary.
I have a similar 3ttt handlebar in a 26.0 stem, after 27 years it still fits perfect.

+1   I have never used a shim or had any problems.
Most people tip-toe through life hoping the make it safely to death.
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Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #8 on: March 14, 2019, 01:45:41 pm »
No shim is necessary.
I have a similar 3ttt handlebar in a 26.0 stem, after 27 years it still fits perfect.

+1   I have never used a shim or had any problems.

Okay, interesting! I'll see what Mercian think, was thinking of putting them on the Strada Speciale they're building for me.
Old enough to know better, but young enough to do it anyway

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #9 on: March 14, 2019, 03:01:32 pm »
I think if you can fit a shim, you should. 0.2mm undersize results in a clamp that moves ~0.65mm more than it should, at which point it isn't usually round any more, amongst other things.

cheers

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #10 on: March 14, 2019, 04:15:15 pm »
25.8 is supposed to fit either 25.4 or 26.0.  Try it and see.  IME 26.0 bars will NOT fit a 25.8mm stem, so it's a bit hopeful.
Never tell me the odds.

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #11 on: March 14, 2019, 07:25:01 pm »
Except he has a 26 stem and 25.8 bars.

I don't think it's any more likely to creak, in fact I'd concur with what Brucey says (always good advice) and think it'd be less likely to.
Bread of heaven, bread of heaven.

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #12 on: March 14, 2019, 10:58:30 pm »
Except he has a 26 stem and 25.8 bars.

Yes, Stem is 26mm Nitto Pearl, bars 25.8mm - I guess technically a 0.1mm shim would be ideal, as would add 0.2mm to the diameter of the bar clamping area.

Quote
I don't think it's any more likely to creak, in fact I'd concur with what Brucey says (always good advice) and think it'd be less likely to.

Would the shim need to be as wide as the stem head, or a bit less?
Old enough to know better, but young enough to do it anyway

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #13 on: March 15, 2019, 01:06:49 pm »
I'd make it the same width. Coke cans are easy to cut, can even use scissors, so you can get it very accurate.
Bread of heaven, bread of heaven.

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #14 on: March 15, 2019, 01:15:13 pm »
I'd make it the same width. Coke cans are easy to cut, can even use scissors, so you can get it very accurate.

and in terms of length, I guess not quite 100% circumference, as the area in the gap by the clamp bolt would probably not need to be shimmed?:



Old enough to know better, but young enough to do it anyway

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #15 on: March 15, 2019, 01:25:43 pm »
I suppose it depends on the thickness of the can. When I did it I wrapped it one and a half times around the bar, not sure why, I can't remember measuring the can thickness.
In the interests of accuracy, I've just measured a Guinness can and it's almost exactly 0.1 mm.
Bread of heaven, bread of heaven.

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #16 on: March 15, 2019, 01:44:54 pm »
I suppose it depends on the thickness of the can. When I did it I wrapped it one and a half times around the bar, not sure why, I can't remember measuring the can thickness.
In the interests of accuracy, I've just measured a Guinness can and it's almost exactly 0.1 mm.

Given that I only need to shim for a 0.2mm difference, a 0.1mm shim should only need a single wrapping, I think. Sounds like an excuse to buy a can of Guinness, though :-)
Old enough to know better, but young enough to do it anyway

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #17 on: March 15, 2019, 02:16:48 pm »
The difficult bit will probably be getting the shim into the gap between stem and bars without mangling it.
It may be worth wedging the stem open a little. If you can fit the stem bolt from the other side (rear), a penny blanking off the hole in the front should work well.

Also, don't be tempted to use an over-width shim and trim it later. It would be easy to score the bar next to the clamp, which would likely result in the bar breaking in due course.

zigzag

  • unfuckwithable
Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #18 on: March 15, 2019, 02:44:55 pm »
this handlebar shape, is it designed to ride mainly in drops? if i wanted to make the tops usable (where i spend 80% of my time) handlebars would need to be rotated quite some way up making reach very long and drops pointing 45deg to the ground..

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #19 on: March 16, 2019, 06:19:00 pm »
this handlebar shape, is it designed to ride mainly in drops? if i wanted to make the tops usable (where i spend 80% of my time) handlebars would need to be rotated quite some way up making reach very long and drops pointing 45deg to the ground..

Well if not these bars, what else would people recommend for a 26mm quill stem on a road bike (they're not for a tourer/randonneur) using Campagnolo Ergos (the older 10-speed style)? Looking for something with around 85mm reach +/- 5-10mm

The Nitto M177 "Noodle" bars have flatter ramps, but also have the prominent tops swept back (albeit with a slight flare in the drops), which I can see potentially getting in the way when sprinting in the drops, though maybe that's not an issue in practice? I think they're intended more as a touring/randonneur bar. They also have no cable grooves at all, which may lead to less comfortable grip on the tops and ramps, though I guess that's less of an issue.

There are the Nitto M190 Euro 80 bars, which are designed for Campagnolo Ergos and are double-grooved and have quite flat ramps, and are heat-treated and relatively light, but I'm not a massive fan of the non-round "ergonomic" shape. I guess they don't look too bad on these two road bikes, though:

https://www.flickr.com/photos/76452700@N05/7569137368

https://www.sonnet.cc/road-bike

There are also some more shallow "compact" bar options, which I've not ruled out, but understand that they can be difficult or near impossible to fit on some quill stems, like my Nitto Pearl, due to the tighter curves involved. Also think all of them either have no grooves or just a single front groove e.g. (from highest quality to lowest):

Nitto M106 - if I could get these to fit the stem, I'd be quite interested in these

Soma HWY One

Deda Speciale 26

Does anyone have any experience of any of the above, especially with a Nitto Pearl quill stem? Are there any other bars I should be considering?
Old enough to know better, but young enough to do it anyway

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #20 on: March 16, 2019, 06:29:43 pm »
I prefer flatter ramps than that these days for sure but I don't think you should dismiss handlebars just because they have slopey ramps; it all depends how you ride. Most Italian handlebars through the 1980s and 1990s had similarly slopey ramps. Indeed having different bars on different bikes is OK too; arguably if you have more than one bike it is because you want to do more than one type of riding, after all....?

cheers

Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #21 on: March 16, 2019, 07:23:43 pm »
I prefer flatter ramps than that these days for sure but I don't think you should dismiss handlebars just because they have slopey ramps; it all depends how you ride. Most Italian handlebars through the 1980s and 1990s had similarly slopey ramps. Indeed having different bars on different bikes is OK too; arguably if you have more than one bike it is because you want to do more than one type of riding, after all....?

The bars in question are intended for my new Mercian Strada Speciale road bike frame (which, incidentally, I've just heard from Mercian about, as they're apparently ready to start production on it now, and want to clarify some things, like my final paint choices... not too bad, considering I ordered it last June) -  this bike is intended for fast training rides (i.e. attempting to get fitter), group rides with my local cycling club, faster social rides with friends and the odd sportive. Probably no actual racing, but you never know. I have other bikes for commuting, touring, doing the shopping etc.  For the closely-bunched club rides, in particular, I would want a comfortable position on the hoods, though.

What does everyone else here use on their bikes which have quill stems?
Old enough to know better, but young enough to do it anyway

zigzag

  • unfuckwithable
Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #22 on: March 16, 2019, 10:00:48 pm »
i've used such bars with a quill stem, but chopped and flipped round like mini bullhorns - the only way to make them usable, ime. there's a good reason (almost)no-one rides with them anymore.
perhaps a different stem would allow different/better/wider choice of handlebars?..

LittleWheelsandBig

  • Whimsy Rider
Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #23 on: March 16, 2019, 10:05:24 pm »
Meh, I like a variety of drop bar shapes, including similar to those. The concept that they are unusable because the shape is out of fashion is amusing though.
Wheel meet again, don't know where, don't know when...

zigzag

  • unfuckwithable
Re: Is it necessary to use a shim to fit 25.8mm 3TTT bars to a 26mm stem?
« Reply #24 on: March 16, 2019, 10:20:29 pm »
Meh, I like a variety of drop bar shapes, including similar to those. The concept that they are unusable because the shape is out of fashion is amusing though.

not so much about fashion, but about how the hand is positioned on the shifter. with the sloping ramps your hands rest on the delicate bit between the thumb and index fingers, which gets painful quite soon. when the ramp is flat or slightly upward the weight is supported by the strongest part of your palm (the one you can chop boards and bricks with), therefore there's no problem spending even long days in such position. my experience can be different to yours (or anyone else's), mind.