....still new to threadless headsets and forks. ...about to install a carbon fiber fork with CF steerer tube (1.125"😉 on a frame with a King headset installed.
I've seen different instructions. Some speak about looking for looseness in the fork after adjusting the preload, others speak about torquing the headset cap bolt to a certain amount prior to clamping the stem, others about turning the bolt a certain number of turns after the cap contacts the stem or spacers above the stem.
Is there any consensus about how tight to have one of these systems?
By the way, is there any reason other than cosmetics to reduce the steerer tube height from my current 25mm above the stem (with corresponding spacers) to a shorter amount? Other than looks, I see no real mechanical reason why this amount would make anything weaker in any way. Most instructions say that 40mm is the max for a 1.125" steerer.
"Jeff" <[email hidden]> wrote in news:[email hidden]:
Quoted message said:
I've seen different instructions. Some speak about looking for looseness in the fork after adjusting the preload, others speak about torquing the headset cap bolt to a certain amount prior to clamping the stem, others about turning the bolt a certain number of turns after the cap contacts the stem or spacers above the stem.
Try www.parktool.com
Quoted message said:
By the way, is there any reason other than cosmetics to reduce the steerer tube height from my current 25mm above the stem (with corresponding spacers) to a shorter amount? Other than looks, I see no real mechanical reason why this amount would make anything weaker in any way. Most instructions say that 40mm is the max for a 1.125" steerer.
A big stack of spacers above the stem is weaker because the compression plug is not inside the stem. This more a problem with carbon steering tubes than with metal.
...still new to threadless headsets and forks. ...about to install a carbon fiber fork with CF steerer tube (1.125"😉 on a frame with a King headset installed.
I've seen different instructions. Some speak about looking for looseness in the fork after adjusting the preload, others speak about torquing the headset cap bolt to a certain amount prior to clamping the stem, others about turning the bolt a certain number of turns after the cap contacts the stem or spacers above the stem.
Is there any consensus about how tight to have one of these systems?
As loose as possible with zero play - there's probably about as much consensus on that as any bike-related topic you'll find.
Using torque or counting rotations on the top cap are really only close to useful for explaining the basic idea of how to do it - in practice neither are really precise enough and are only able to usually get you in the ballpark. After you make an initial adjustment, you should indeed check for play or tightness, ideally using some different methods. It's best technically to start with a conservative (somewhat likely to be looser than needed) adjustment and work from there; eventually you'll get a feel and be faster. Also, you don't need to fully secure your stem bolts until you've tested the adjustment. Here are the steps I go through: Forcefully rock fork/bars back and fourth with the front end off the ground and frame held in a way where play can be felt. In non-suspended bikes, lift front end off the ground and drop it from a few inches, which can show looseness via a characteristic rattle. With both wheels on the ground, turn the fork/bars 90 degrees and firmly jerk the bike forward via the frame, which will let you feel play in the headset. You can sometimes accomplish the same thing by locking the front brake, and some people always do this, but it's often difficult to confidently tell brake pivot play apart from hs play. Lift the whole bike up without holding the fork/bars, and with the front end pointed down, slowly move the rest of the bike laterally back and fourth. This lets you see how freely the front end is moving. It generally should move very freely on a well-adjusted hs.
...still new to threadless headsets and forks. ...about to install a carbon fiber fork with CF steerer tube (1.125"😉 on a frame with a King headset installed.
I've seen different instructions. Some speak about looking for looseness in the fork after adjusting the preload, others speak about torquing the headset cap bolt to a certain amount prior to clamping the stem, others about turning the bolt a certain number of turns after the cap contacts the stem or spacers above the stem.
Is there any consensus about how tight to have one of these systems?
By the way, is there any reason other than cosmetics to reduce the steerer tube height from my current 25mm above the stem (with corresponding spacers) to a shorter amount? Other than looks, I see no real mechanical reason why this amount would make anything weaker in any way. Most instructions say that 40mm is the max for a 1.125" steerer.
Max for most forks is 40mm under the stem..and 5mm above recommended so all the stem clamps a portion of the steerer but having some above does give you some flexibility in sizing until you are sure..then can cut. Always easier to make the steerer shorter.
...still new to threadless headsets and forks. ...about to install a carbon fiber fork with CF steerer tube (1.125"😉 on a frame with a King headset installed.
I've seen different instructions. Some speak about looking for looseness in the fork after adjusting the preload, others speak about torquing the headset cap bolt to a certain amount prior to clamping the stem, others about turning the bolt a certain number of turns after the cap contacts the stem or spacers above the stem.
Is there any consensus about how tight to have one of these systems?
what works for me is to use the long leg of the allen wrench in the tightening bolt and use finger tight on the short leg. that prevents too much torque, but allows you to get it tight enough. i've never seen a manufacturer spec for this procedure.
Quoted message said:
By the way, is there any reason other than cosmetics to reduce the steerer tube height from my current 25mm above the stem (with corresponding spacers) to a shorter amount? Other than looks, I see no real mechanical reason why this amount would make anything weaker in any way. Most instructions say that 40mm is the max for a 1.125" steerer.
Jeff
there is a limit to how many below [leverage], but not above [no leverage] - simply cosmetics.
"Qui si parla Campagnolo-www.vecchios.com" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
Max for most forks is 40mm under the stem..and 5mm above recommended so all the stem clamps a portion of the steerer but having some above does give you some flexibility in sizing until you are sure..then can cut.
I've seen the 40mm listed as 40mm total and 40mm below. I've also seen the recommendation of 5mm max above, but also no limit above. I've also seen it listed as 5mm minimum.
I can't understand what difference the length above would have other than placing the expander within the stem for extra strength as another person already mentioned and the fact that you would want a spacer above to keep the steerer within the stem.
You are suggesting 5mm above as a minimum correct? (and not a maximum)
"Qui si parla Campagnolo-www.vecchios.com" <[email hidden]> wrote in messagenews:[email hidden]...
Quoted message said:
Max for most forks is 40mm under the stem..and 5mm above recommended so all the stem clamps a portion of the steerer but having some above does give you some flexibility in sizing until you are sure..then can cut.
I've seen the 40mm listed as 40mm total and 40mm below. I've also seen the recommendation of 5mm max above, but also no limit above. I've also seen it listed as 5mm minimum.
I can't understand what difference the length above would have other than placing the expander within the stem for extra strength as another person already mentioned and the fact that you would want a spacer above to keep the steerer within the stem.
You are suggesting 5mm above as a minimum correct? (and not a maximum)
The 5mm above minimum for a carbon steerer would be to not wanting the fragile edge of the carbon steerer being clamped by the stem. More strength in the steerer if you are compressing the whole circumference and not clamping on the open end of the carbon steerer. Probably not a huge difference in strength, but it does not hurt to have a bit of extra insurance for free.
...still new to threadless headsets and forks. ...about to install a carbon fiber fork with CF steerer tube (1.125"😉 on a frame with a King headset installed.
I've seen different instructions. Some speak about looking for looseness in the fork after adjusting the preload, others speak about torquing the headset cap bolt to a certain amount prior to clamping the stem, others about turning the bolt a certain number of turns after the cap contacts the stem or spacers above the stem.
Is there any consensus about how tight to have one of these systems?
By the way, is there any reason other than cosmetics to reduce the steerer tube height from my current 25mm above the stem (with corresponding spacers) to a shorter amount? Other than looks, I see no real mechanical reason why this amount would make anything weaker in any way. Most instructions say that 40mm is the max for a 1.125" steerer.
Jeff
Jeff, get the damn thing in your frame.. ;-) It takes an averaged person about half an hour. You worry to much. Adjusting a threadless headset is the same as a threaded one: begin at the loose side and after adjusting look for looseness by rocking the bike back and forth or dropping it from a few inches and listen if it rattles. My experience is that a King headset is quite forgiving. A 5 mm spacer above the stem doesn't hurt (I think it doesn't make much of a difference with a decent expansion plug) and use a torque wrench and a decent stem.
"Lou Holtman" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
Jeff, get the damn thing in your frame.. ;-) It takes an averaged person about half an hour. You worry to much. Adjusting a threadless headset is the same as a threaded one: begin at the loose side and after adjusting look for looseness by rocking the bike back and forth or dropping it from a few inches and listen if it rattles. My experience is that a King headset is quite forgiving. A 5 mm spacer above the stem doesn't hurt (I think it doesn't make much of a difference with a decent expansion plug) and use a torque wrench and a decent stem.
Lou
Thanks Lou (and others) - I would normally agree with you about just doing it and being able to alter things later.
....but since I'm still waiting on a few parts (...should be here by the end of the week), I still have some time to ask a few advanced questions. So far I only have the derailleurs and brakes installed and was messing with the fork/headset a bit yesterday. ...need the campy BB wrench I ordered to finish installing the crank and still need the handlebars to actually get the cables on. Since I've only built up about 4 bikes in the past, I'm still a bit nervous about working with components that ran me several times my monthy mortgage. If all goes well, I should have this up and riding by the weekend.
"Lou Holtman" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
Jeff, get the damn thing in your frame.. ;-) It takes an averaged person about half an hour. You worry to much. Adjusting a threadless headset is the same as a threaded one: begin at the loose side and after adjusting look for looseness by rocking the bike back and forth or dropping it from a few inches and listen if it rattles. My experience is that a King headset is quite forgiving. A 5 mm spacer above the stem doesn't hurt (I think it doesn't make much of a difference with a decent expansion plug) and use a torque wrench and a decent stem.
Lou
Thanks Lou (and others) - I would normally agree with you about just doing it and being able to alter things later.
....but since I'm still waiting on a few parts (...should be here by the end of the week), I still have some time to ask a few advanced questions. So far I only have the derailleurs and brakes installed and was messing with the fork/headset a bit yesterday. ...need the campy BB wrench I ordered to finish installing the crank and still need the handlebars to actually get the cables on. Since I've only built up about 4 bikes in the past, I'm still a bit nervous about working with components that ran me several times my monthy mortgage. If all goes well, I should have this up and riding by the weekend.
"jim beam" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
what works for me is to use the long leg of the allen wrench in the tightening bolt and use finger tight on the short leg. that prevents too much torque, but allows you to get it tight enough.
So how do you know it's not "too much"? Idiot.
Quoted message said:
there is a limit to how many below [leverage], but not above [no leverage] - simply cosmetics.
