Handlebar fitment concerns, diameter
#1
Senior Member
Thread Starter
Join Date: Apr 2011
Location: Maryland, USA
Posts: 2,441
Bikes: Drysdale/Gitane/Zeus/Masi/Falcon/Palo Alto/Raleigh/Legnano
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 987 Post(s)
Liked 639 Times
in
406 Posts
Handlebar fitment concerns, diameter
As I was musing in another topic, on my 1974 Zeus track bike project, “It has been 45 years but I am pretty sure the bar and stem came to me together; I knew someone with a Favorit bike and was upgrading one component at a time and I bought these from him. I like the combination of steel and aluminum on the stem, to me it “looks right” on a track bike. Oddly, there is no raised center section on the bars and the stem really does not want to tighten down snug.” Well, between them appearing a bit bent and the clamp-down issue, perhaps I should replace the bars and keep the stem; I suspect I’ll have to hacksaw the bars to get them off. The micrometer reads the bar diameter at 23.7mm, and I’ve only found a couple of websites selling classically-shaped bars (I could use advice on sources) and not much below a center diameter of 25.4mm. Are there other sizes out there? If this is some odd Czech-only size perhaps the bar and stem both have to go… sad.
__________________
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
#2
Senior Member
Join Date: Sep 2005
Location: Oakland, CA
Posts: 3,265
Bikes: '82 Univega Competizione, '72 Motobecane Grand Record, '83 Mercian KOM Touring, '85 Univega Alpina Uno, '76 Eisentraut Limited
Mentioned: 57 Post(s)
Tagged: 0 Thread(s)
Quoted: 1088 Post(s)
Liked 1,205 Times
in
701 Posts
Maybe the bars are supposed to be 23.8 and it's just a tight fit (or corroded together?). Sheldon's crib sheet says in row 2 that obsolete British steel drop bars would have been sized at 23.8mm at the clamp: https://www.sheldonbrown.com/cribsheet-handlebars.html
#3
Senior Member
Thread Starter
Join Date: Apr 2011
Location: Maryland, USA
Posts: 2,441
Bikes: Drysdale/Gitane/Zeus/Masi/Falcon/Palo Alto/Raleigh/Legnano
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 987 Post(s)
Liked 639 Times
in
406 Posts
Maybe the bars are supposed to be 23.8 and it's just a tight fit (or corroded together?). Sheldon's crib sheet says in row 2 that obsolete British steel drop bars would have been sized at 23.8mm at the clamp: https://www.sheldonbrown.com/cribsheet-handlebars.html
So I am inclined to locate some nicer bars; perhaps start with a WTB here at C&V/BF? Not tied to a particular brand, maybe GB, or TTT or, hmm, what other brands should I be considering? And I'm right that the only diameter to worry about is at the clamp, no? With all 1'" steerers, the insertion diameter is a constant? That does not sound right, there's no universal diameter for anything.
__________________
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
#4
Senior Member
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,624
Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1324 Post(s)
Liked 927 Times
in
640 Posts
Is it possible that bar was supposed to be used with a shim?
Cheers
Cheers
#5
Senior Member
Thread Starter
Join Date: Apr 2011
Location: Maryland, USA
Posts: 2,441
Bikes: Drysdale/Gitane/Zeus/Masi/Falcon/Palo Alto/Raleigh/Legnano
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 987 Post(s)
Liked 639 Times
in
406 Posts
Hmm, I do have a package of assorted-size brass shim stock I had used for automotive purposes -- if I could being myself to trust such a connection to hold and not slip and the worst moment.
__________________
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
#7
Senior Member
Thread Starter
Join Date: Apr 2011
Location: Maryland, USA
Posts: 2,441
Bikes: Drysdale/Gitane/Zeus/Masi/Falcon/Palo Alto/Raleigh/Legnano
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 987 Post(s)
Liked 639 Times
in
406 Posts
Micrometer says about 22mm for insertion into the steerer... common size?
__________________
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
#9
Senior Member
Join Date: Apr 2005
Location: Ann Arbor, MI
Posts: 16,880
Bikes: 1980 Masi, 1984 Mondonico, 1984 Trek 610, 1980 Woodrup Giro, 2005 Mondonico Futura Leggera ELOS, 1967 PX10E, 1971 Peugeot UO-8
Mentioned: 49 Post(s)
Tagged: 0 Thread(s)
Quoted: 1858 Post(s)
Liked 664 Times
in
506 Posts
I would say, you NEED to have the ID of the stem handlbar mounting bore and the center of the handlebar OD match. If the bar is too big, the stam clamp should fraccture as you tighten the clap bolt. the bar is too smal for the stem, you will over tighten the clamp screw and possibly never achieve tension. And due to the over tightening, it could still fracture the stem.
When the stem fractures, if you are riding, you will most likely crash and hit the ground, possibly with your face.
There are many sizes for the parts in question, and if they are now distorted, they are already over stressed and hence dangerous. Aluminum does not like to be cold-set.
When the stem fractures, if you are riding, you will most likely crash and hit the ground, possibly with your face.
There are many sizes for the parts in question, and if they are now distorted, they are already over stressed and hence dangerous. Aluminum does not like to be cold-set.
#10
Phyllo-buster
Join Date: Jan 2010
Location: Nova Scotia
Posts: 8,847
Bikes: roadsters, club bikes, fixed and classic
Mentioned: 133 Post(s)
Tagged: 0 Thread(s)
Quoted: 2298 Post(s)
Liked 2,055 Times
in
1,255 Posts
I have dated 1951 Reynolds drop bars that are 23.8 and require a shim to fit old GB Hidminium bars. I suspect this was always a thing.
Brass shim stock will work in most any application as will aluminum. I make sure to have any gap or overlap centred in the opening in the stem to prevent stress risers
Brass shim stock will work in most any application as will aluminum. I make sure to have any gap or overlap centred in the opening in the stem to prevent stress risers
Last edited by clubman; 01-14-22 at 06:14 PM.
#11
Senior Member
Join Date: Jun 2014
Location: Ontario, Canada
Posts: 4,624
Bikes: iele Latina, Miele Suprema, Miele Uno LS, Miele Miele Beta, MMTB, Bianchi Model Unknown, Fiori Venezia, Fiori Napoli, VeloSport Adamas AX
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1324 Post(s)
Liked 927 Times
in
640 Posts
Bent handlebar? Deep scoring at one of the bends? In retrospect I'd ditch that handlebar and get something else that I could be sure wouldn't fail in use.
Prying alloy stems very much isn't a good idea either as you can easily introduce stress risers.
You really don't want a handlebar or stem failing on a fast ride or in traffic.
Cheers
Prying alloy stems very much isn't a good idea either as you can easily introduce stress risers.
You really don't want a handlebar or stem failing on a fast ride or in traffic.
Cheers
#12
Senior Member
Join Date: Nov 2004
Posts: 23,223
Mentioned: 654 Post(s)
Tagged: 1 Thread(s)
Quoted: 4722 Post(s)
Likes: 0
Liked 3,038 Times
in
1,876 Posts
I have dated 1951 Reynolds drop bars that are 23.8 and require a shim to fit old GB Hidminium bars. I suspect this was always a thing.
Brass shim stock will work in most any application as will aluminum. I make sure to have any gap or overlap centred in the opening in the stem to prevent stress risers
Brass shim stock will work in most any application as will aluminum. I make sure to have any gap or overlap centred in the opening in the stem to prevent stress risers
Likes For T-Mar:
#13
Phyllo-buster
Join Date: Jan 2010
Location: Nova Scotia
Posts: 8,847
Bikes: roadsters, club bikes, fixed and classic
Mentioned: 133 Post(s)
Tagged: 0 Thread(s)
Quoted: 2298 Post(s)
Liked 2,055 Times
in
1,255 Posts
Yes, I meant Hidminium stems.
#14
Senior Member
Thread Starter
Join Date: Apr 2011
Location: Maryland, USA
Posts: 2,441
Bikes: Drysdale/Gitane/Zeus/Masi/Falcon/Palo Alto/Raleigh/Legnano
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 987 Post(s)
Liked 639 Times
in
406 Posts
Yes, that was a pretty common English handlebar standard, as 23.8mm is the metric equivalentt of 15/16". I've seen lots of English bars that used a shim to accommodate the stem. My only shim advice is to to not build up the shim with several pieces of stock. Use a single piece of the correct thickness. The more layers between the bar and stem, the greater the chance of slippage.
__________________
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
#15
Senior Member
Join Date: Apr 2005
Location: Ann Arbor, MI
Posts: 16,880
Bikes: 1980 Masi, 1984 Mondonico, 1984 Trek 610, 1980 Woodrup Giro, 2005 Mondonico Futura Leggera ELOS, 1967 PX10E, 1971 Peugeot UO-8
Mentioned: 49 Post(s)
Tagged: 0 Thread(s)
Quoted: 1858 Post(s)
Liked 664 Times
in
506 Posts
You got that right! Maybe they bent the bars to shape from straight stock after passing through the stem?
Micrometer says about 24.7mm inside diameter. How do I know? Because...
Upon reflection, I decided that's correct. So, to possibly save the stem, I hacksawed the bars to release the stem. So, my WTB 1.0 is to find bars to fit, my WTB 2.0 would be bars and a stem. Unsure what bars fit a 24.7mm hole.
Presuming I found some 23.8's, to fit a 24.7mm stem means 0.45mm shim. AM i calculating that right at 17.72 1000th's of an inch thick? Less any desired clearance, if indeed any is desired (I'm going through a "clearance crisis" on a seat post now at the same time).
Micrometer says about 24.7mm inside diameter. How do I know? Because...
Upon reflection, I decided that's correct. So, to possibly save the stem, I hacksawed the bars to release the stem. So, my WTB 1.0 is to find bars to fit, my WTB 2.0 would be bars and a stem. Unsure what bars fit a 24.7mm hole.
Presuming I found some 23.8's, to fit a 24.7mm stem means 0.45mm shim. AM i calculating that right at 17.72 1000th's of an inch thick? Less any desired clearance, if indeed any is desired (I'm going through a "clearance crisis" on a seat post now at the same time).
Anything I can try to help with, HMU.
#16
Senior Member
Thread Starter
Join Date: Apr 2011
Location: Maryland, USA
Posts: 2,441
Bikes: Drysdale/Gitane/Zeus/Masi/Falcon/Palo Alto/Raleigh/Legnano
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 987 Post(s)
Liked 639 Times
in
406 Posts
Perhaps it is not worth beating myself to death looking for bars to fit this oddball stem which is not original to the frame anyway.
__________________
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
Larry:1958 Drysdale, 1961 Gitane Gran Sport, 1974 Zeus track, 1988 Masi Gran Corsa, 1974 Falcon, 1980 Palo Alto, 1973 Raleigh Gran Sport, 1974 Legnano. Susan: 1976 Windsor Profesional.
#17
Senior Member
Join Date: Apr 2005
Location: Ann Arbor, MI
Posts: 16,880
Bikes: 1980 Masi, 1984 Mondonico, 1984 Trek 610, 1980 Woodrup Giro, 2005 Mondonico Futura Leggera ELOS, 1967 PX10E, 1971 Peugeot UO-8
Mentioned: 49 Post(s)
Tagged: 0 Thread(s)
Quoted: 1858 Post(s)
Liked 664 Times
in
506 Posts
Well, yeah, you have the right io cut your losses.
#18
Senior Member
Join Date: Oct 2011
Location: Fairplay Co
Posts: 9,523
Bikes: Current 79 Nishiki Custum Sport, Jeunet 620, notable previous bikes P.K. Ripper loop tail, Kawahara Laser Lite, Paramount Track full chrome, Raliegh Internatioanl, Motobecan Super Mirage. 59 Crown royak 3 speed
Mentioned: 26 Post(s)
Tagged: 1 Thread(s)
Quoted: 790 Post(s)
Liked 1,769 Times
in
635 Posts
Being classic metric the Zeus stuff is true 25.00 but has a bit of wiggle so you may be able to get french stuff to work,