Retro mountain bike stem compatibility
06-29-18, 02:28 PM
#1
Senior Member
Thread Starter
Retro mountain bike stem compatibility
Hi folks
Apologies in advance if this is considered a stupid question. I've searched the forums and the big G and I can't find a definitive answer.
I have a 1991/2? Marin Palisades Trail which I'm converting to drop bars as an experiment. The stem takes 25.4mm bars, and the drop bars I have are 25.4mm. However, the clamp area is so wide that I can't get the bars in at the bends. Even though the stem is steel, I don't want to force it to open up and end up damaging it. Now I know the answer is probably no, but am I missing something? I saw a video recently on YT where a guy converted his retro mtb to drop bars using the original stem (although the clamp area did look narrower). Maybe my stem clamp is just too wide?
I tried using a stem from an old road bike, but discovered that the stem diameters are different...
Anyone managed this using the original mtb stem? It would be great to use it as it also saves getting hold of a cable stop for the caliper brakes.
Apologies in advance if this is considered a stupid question. I've searched the forums and the big G and I can't find a definitive answer.
I have a 1991/2? Marin Palisades Trail which I'm converting to drop bars as an experiment. The stem takes 25.4mm bars, and the drop bars I have are 25.4mm. However, the clamp area is so wide that I can't get the bars in at the bends. Even though the stem is steel, I don't want to force it to open up and end up damaging it. Now I know the answer is probably no, but am I missing something? I saw a video recently on YT where a guy converted his retro mtb to drop bars using the original stem (although the clamp area did look narrower). Maybe my stem clamp is just too wide?
I tried using a stem from an old road bike, but discovered that the stem diameters are different...
Anyone managed this using the original mtb stem? It would be great to use it as it also saves getting hold of a cable stop for the caliper brakes.
Last edited by tonyfourdogs; 06-29-18 at 02:53 PM.
06-29-18, 05:35 PM
#2
Nigel
Join Date: Mar 2011
Location: San Jose, CA
Posts: 2,991
Bikes: 1980s and 1990s steel: CyclePro, Nishiki, Schwinn, SR, Trek........
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 384 Post(s)
Likes: 0
Liked 6 Times
in
6 Posts
The stem is steel ???? Please check with a magnet. I strongly suspect that it is aluminum. Aluminum does not like to be over bent and bent back.
06-29-18, 08:47 PM
#3
Senior Member
Join Date: Feb 2012
Location: Rochester, NY
Posts: 18,094
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4210 Post(s)
Liked 3,875 Times
in
2,315 Posts
Yes, stem/bar clamp widths is a spec that counts if you want to keep the bars un scathed. Andy
__________________
AndrewRStewart
AndrewRStewart
06-30-18, 01:43 AM
#4
Senior Member
Thread Starter
I will check that. Although I'm pretty sure I cleaned rust off the stem when I was restoring the bike, but I agree stems have been alu/alloy mostly in my experience too. Thanks
06-30-18, 11:54 AM
#5
Banned
fork steerers come in 7/8" 22.2mm they call it a 1" because they are talking about the outside diameter
of the fork
next came a fork with a 1" inside, and a 1 1/8" outside.. some were threaded , now a lot are threadless.
you can get conversion plugs to use in a threaded fork, and then put a threadless stem on that.
of the fork
next came a fork with a 1" inside, and a 1 1/8" outside.. some were threaded , now a lot are threadless.
you can get conversion plugs to use in a threaded fork, and then put a threadless stem on that.
06-30-18, 01:50 PM
#6
Senior Member
Thread Starter
fork steerers come in 7/8" 22.2mm they call it a 1" because they are talking about the outside diameter
of the fork
next came a fork with a 1" inside, and a 1 1/8" outside.. some were threaded , now a lot are threadless.
you can get conversion plugs to use in a threaded fork, and then put a threadless stem on that.
of the fork
next came a fork with a 1" inside, and a 1 1/8" outside.. some were threaded , now a lot are threadless.
you can get conversion plugs to use in a threaded fork, and then put a threadless stem on that.
06-30-18, 04:15 PM
#7
Calamari Marionette Ph.D
It's a 1-1/8 inch quill. The standard of old MTBs. A variety can be found on the bay. Nitto even makes one that would work.
06-30-18, 04:23 PM
#8
Senior Member
Join Date: Oct 2016
Location: San Mateo,Ca.
Posts: 3,988
Bikes: TRIMMED DOWN THE HERD
Mentioned: 46 Post(s)
Tagged: 0 Thread(s)
Quoted: 1092 Post(s)
Liked 936 Times
in
601 Posts
06-30-18, 04:30 PM
#9
Bikes are okay, I guess.
Join Date: Jan 2015
Location: Richmond, Virginia
Posts: 6,938
Bikes: Waterford Paramount Touring, Giant CFM-2, Raleigh Sports 3-speeds in M23 & L23, Schwinn Cimarron oddball build, Marin Palisades Trail dropbar conversion, Nishiki Cresta GT
Mentioned: 69 Post(s)
Tagged: 0 Thread(s)
Quoted: 2647 Post(s)
Liked 2,446 Times
in
1,557 Posts
Probably not recommended but I have done this on my own bike, grind the stem at the bottom near the pinch bolt so the clamp part does not have parallel ends but is sort of V-shaped. May take more of an angle than the stem shown, so grind a little and test fit, repeat as necessary.
06-30-18, 05:34 PM
#10
Senior Member
Yeah that works. Road stems typically have that V for dealing with bends in road-bars. Also helps if you rotate bar so that narrow part of V is on inside-radius of bar.
Another tip: remove clamp-bolt and insert penny into slot. Install bolt from back side (threaded side), and turn it to press against penny and it'll spread clamp to make getting bars through easier.
Steel's much more forgiving of abuse than aluminium so not too much to worry about. It has much, much higher strength per unit-volume than aluminium (that's why less is used), and also has fatigue-limit which aluminium doesn't. If you keep stresses below certain level, steel will never fail. Aluminium doesn't have fatigue-limit, so any and all stresses will accumulate and part will eventually fail.
Another tip: remove clamp-bolt and insert penny into slot. Install bolt from back side (threaded side), and turn it to press against penny and it'll spread clamp to make getting bars through easier.
Steel's much more forgiving of abuse than aluminium so not too much to worry about. It has much, much higher strength per unit-volume than aluminium (that's why less is used), and also has fatigue-limit which aluminium doesn't. If you keep stresses below certain level, steel will never fail. Aluminium doesn't have fatigue-limit, so any and all stresses will accumulate and part will eventually fail.
07-08-18, 11:22 AM
#11
Senior Member
Thread Starter
So, I finally did it!
I knew the stem was steel, but since there were a few doubters, I decided to buy a quill stem adapter for a modern stem (which I already had).
Fast forward to the stem arriving, and I couldn't use it because the clamp size was too big (I hadn't even considered that). So I rummaged in my bag of parts and found a similar mtb stem, and the bars went of first try - no prising open required. And it was a *very* similar stem to the original marin one.
So I installed the stem/ bars and had to use one of those cable stops that bolts into the top of the forks. However, it wasn't high enough, and I couldn't wire the brakes so they'd actually stop the wheel.
In desperation, I went a got my magnet, confirmed my existing stem (with cable stop brazed on) was steel, prised it open just a little, installed the bars, and now the project's complete!
If only I'd tried to work with what I already had in the first place I'd have saved so much time!
Thanks to everyone who replied. Drop bar retro mtb projects highly recommended. It's loads of fun to ride
I knew the stem was steel, but since there were a few doubters, I decided to buy a quill stem adapter for a modern stem (which I already had).
Fast forward to the stem arriving, and I couldn't use it because the clamp size was too big (I hadn't even considered that). So I rummaged in my bag of parts and found a similar mtb stem, and the bars went of first try - no prising open required. And it was a *very* similar stem to the original marin one.
So I installed the stem/ bars and had to use one of those cable stops that bolts into the top of the forks. However, it wasn't high enough, and I couldn't wire the brakes so they'd actually stop the wheel.
In desperation, I went a got my magnet, confirmed my existing stem (with cable stop brazed on) was steel, prised it open just a little, installed the bars, and now the project's complete!
If only I'd tried to work with what I already had in the first place I'd have saved so much time!
Thanks to everyone who replied. Drop bar retro mtb projects highly recommended. It's loads of fun to ride
