tapered roller bearing steering stem fitment

[mikefealk]

so i am reassembling the front end. the po installed tapered bearings in the stem in place of the ball bearings. i can torque down the large nut on top all the way down and it still wont achieve any resistance in the bearings. there is no noticeable play in the stem, but i feel like i should be able to tighten up the pressure on the bearings. the nut bottoms out before i can get that. anyone experienced this?

[tz375]

That is probably because the steering stem needs to be machined a touch to allow the top bearing to move down a little.

[mikefealk]

ya that makes sense. its allllmost where i would want the tension, and its all put toghether. ill call it good and see if it wobbles. lol.

[tz375]

If the bike is on the ground, pull on the front brake and rock the bike back and forwards and see if there is any play. It may loosen up over time, so keep an eye on it.

In my last post, I assumed that you had removed or loosened the top triple clamp and it's the ring nut under the top clamp that we are talking about. All you said was teh large nut and I assumed you mean the lower one, not the nut above the top triple clamp.

[mikefealk]

yes the large spanner nut under the upper tree. i torqued it all the way down and i guess once the bearing bottoms out on the lip of the stem, thats all the pressure you will achieve. milling another few millimeters down the stem...is that a common thing to have to do when replacing the ball bearings with rollers?

[Alan H]

Yes, IIRC about another 6mm.

[tz375]

In theory, the stem is put in a lathe and turned down a little bit further, but in many cases, the stem only has to be reduced in diameter by 1-2mm over 3-4mm length and that can be done carefully with a dremmel and sanding drum.

[Alan H]

I did mine with a length of fine emery tape and a lot of to-ing and fro-ing.
Problem with doing it in a lathe is the bottom triple tree which causes the rotating mass to be out of balance and has a large rotating radius. My lathe is only small so couldn't fit it anyway.
I was going to extent the top part to the chuck and allow the triple tree to hang over the lathe bed end while carrying the base end in a steady which would stop the rotating mass wobbling, but using it once every few years isn't worth the effort.
Emery tape is cheaper and less hassle!!

[mikefealk]

thanks guys, i guess i will take the front end back apart and remove some material. sigghhhhhh. got to do it right.

[mikefealk]

well i took the lip down about 3 mm and it seems to be about right, maybe shoulda gone further down the shaft. i also realized that the dust cap has to be made thinner to accomadate the spanner nut going further down the threads

[yeadon_m]

Mike,

This method of stem thinning and dust cap slimming down worked for me on 3 x GTs on those tapered roller bearings. Keep at it, it will come right!

Cheers,
Mike

[mikefealk]

thanks alot guys. the hose clamp idea is a great one. i used painters tape and dremeled right up to it. had to have a beer to keep my hand steady though. should be good to go! my crankshaft should be back in a couple days! im sure ill have some more questions for you guys comin. appreciate all the tips and knowledge.

[Eddie]

hi guys, its been a while for me on here, just read this post and wanted let you guys know about my experience, I ordered the tapered bearings from all balls, I got the schematic drawing with the bearings and I took the stem to a friend of mine who has a lathe, he turned it down according to the schematic and I assembled everything, it just seems like after a while it gets loose? I don't want to tighten it to much and mess the bearings up, but after about 3 months of riding it seemed to get loose, so I have to kinda watch it which sucks. I put these bearings in along time ago, I think like about a year or more, I did not get to watch my friend turn the stem but he measured it in front of me and it was right on, so just saying it seems like a common problem with them I guess? I havnt tightened the stem up in a while know but then again I havnt ridden the old girl that much either, just sharing my experience...

[Coyote]

Eddie, something might not be completely seated. Tighten it as tight as you can. Then pick up a cheater and tighten it even more. Everything except the cage is hardened so you won't hurt anything. Then back it off and tune it in from there.

[Eddie]

I feel like I tightened it pretty good the first time, but I didn't use a cheater bar, maybe I will try that, thanks for the help! I called all balls and the guy I talked to back then said they had gotten a lot of calls about this, and he went over how I need to tighten it, which I did exactly what he said and after about 100 miles it seemed to get loose again? I will try what you said and see if it works, it was almost like it didn't seat all the way but I know the guy machined it like the schematic said so im not sure, maybe I just need to torque the crap out of it like you said, then back it off,,, whenever I get to it ill let you guys know what happens...