Anyone converted from Focus straight steerer to "Normal" tapered?

[millemille]

Egg beatered the bike at the weekend and put some scratches into the DLC on my Zeb forks. Cost and lead time of the Focus specific (straight steerer for the 1.5" top and bottom head bearings) Combined Steerer Unit is eye watering but "normal" tapered steerer ones are less painful.

Has anyone converted their SAM2, or other Focus model which uses the same oversized head bearing set up, to use a regular tapered steerer fork?

TIA.

 

[steve_sordy]

I'm hoping to learn something here, but I thought all you had to do on the Focus was to buy different sized bearings and you can use any fork steerer you like.
Go to TrailVision.

 

[millemille]

I'm hoping to learn something here, but I thought all you had to do on the Focus was to buy different sized bearings and you can use any fork steerer you like.
Go to TrailVision.

If you have a bearing with the same outer diameter (frame cup) but smaller inner diameter (steerer) it has to be taller because the balls are larger to make up the difference in inner diameter. So the upper bearing will not be fully seated in the top race frame cup.

The idea is that you'd fit the same upper bearing as normal but then have a split spacer that slides over the smaller diameter steerer and is an interference fit between the bearing inner race and steerer.

I'd hope that there is something available off the shelf?

 

[steve_sordy]

My 2019 Focus Jam2 is a tapered headset. These are the notes I have:

Acros 1-1/8", tapered. This is an integrated headset, hence these bearings (which I bought from Trail Vision):

Upper is IS 41.8 O/D and 30.5 I/D with a 4mm x 45 deg chamfer top inside and bottom outside. Thickness is 8mm.
Lower is IS 52 O/D and 40 I/D with a 1.5mm x 45 deg chamfer top inside and bottom outside. Thickness is 7mm.

Trail Vison are very helpful, maybe they can suggest something?

 

[themoon]

I've installed Cane creek 110, ZS44/28.6 ZS56/40 without any issues

 

[millemille]

I've installed Cane creek 110, ZS44/28.6 ZS56/40 without any issues

Then I'd suggest you don't have a Focus with 1.5" bearings top and bottom as standard.

The Sam2 has 1.5" (56/40) top and bottom as standard.

 

[millemille]

Things I have learnt today...

The Sam2 does have a normal tapered steerer (1 1/2" bottom, 1 1/8" top). I was misinformed by TFTuned. The SAM2 uses a spacer between the steerer, which also contains the cut outs for the cable and hoses which are routed through the stem, to bring the steerer diameter up to 1 1/2" at the top to suit the bigger top bearing...

 

[steve_sordy]

If you have a bearing with the same outer diameter (frame cup) but smaller inner diameter (steerer) it has to be taller because the balls are larger to make up the difference in inner diameter. So the upper bearing will not be fully seated in the top race frame cup.
------------------------

Is this actually fact?
I can visualise bearings with the same ball diameters but with different inner and outer diameters. The inner and/or outer races just become thicker or thinner to suit. Likewise, the balls can be different sizes and still fit into two races, just by cutting bigger or smaller groove diameters. In the latter case, the steps are determined by the requirement to have a whole number of balls running in the race, but even then the spacing between balls can be altered. The bearing designer has a lot to play with. But the whole thing will be dictated by minimum cost for a specific performance and size requirement.

 

[Lee c]

Hey guys sorry to revive the thread but I am looking to change the zeb r forks on my 2022 sam2, what steerer size fork should I be looking for ?