For the machinists

[Kris]

Im going to have a machinist embark on creating a titanium steering column, mostly due to the reduced cost in making one, rather then buying one but my question relates to the length of the column.

Without a template, how would one know the length of the column assuming you have:

Upper/Lower triple
Bearings - so you know the width of the column
Steering lock nuts - so I know the required thread onto the top of the column
Upper Triple Nut - so i know the thread into the column to clamp the fixture together

Is there some kind of gap that needs to be maintained at the bottom of the triple (between the frame and the lower clamp) ?

Cheers

[RIPPERTON]

Why Titanium ?
all sport bike steering columns are Aluminium.
Commuter bike ones would be steel.
Aluminium would be way cheaper even in 7075T6.
So you dont have the original column to go on ?
You will need the frame to figure out how long to make the column.

[Kris]

Because the original one is Titanium

I have an original OEM triple, but the column is totally different. The race triples ive got use an eccentric shaft that allows 25mm or 27.5mm offset, OEM is fixed at 30mm so the column length may be different due to thicknesses in the top/bottom triple itself. Wouldnt be a case of just duplicating it, only thing I can think that would be identical between OEM and the Race triple is the actual shaft diameter (as it uses the same bearings)

I have the frame. Do I just measure the thickness of the headstock, plus the height of the top/bottom triple?
1775

[RIPPERTON]

I would install the bearings into the frame and measure the outside distance apart of the 2 inner races.
then you can add on the length you need to go into the lower triple and upper triple and the distance the nuts take up
plus a mm.

[Kris]

The bearings sit into the steering cups flush and they are in the bike now.

https://www.af1racing.com/store/ProdImages/st3/FL-02SAM.jpg

Cool, so distance is lowest part of the triple, highest part of the nuts when sitting on the dust seal of the bearing plus the upper triple and a mm.

Cool :D Now to find some nice titanium rod

[RIPPERTON]

Watch it, if the lower inner race surface isnt proud a bit the lower triple might rub on the frame as you turn the steering.
Id put a 2mm thick washer between the race and the triple.
I dont use Ti because its too heavy, too expensive and too strong.

[RIPPERTON]

Cool :D Now to find some nice titanium rod

Thyssen Krupp have 50mm x 400mm round bar grade 5 for $415 + GST
9757 7777
Wetheril Park
The same in 7075T6 would be less than $50

[Kris]

Watch it, if the lower inner race surface isnt proud a bit the lower triple might rub on the frame as you turn the steering.
Id put a 2mm thick washer between the race and the triple.
I dont use Ti because its too heavy, too expensive and too strong.

Ill look on my OEM bike and just replicate the distance.

Here is a photo of the triple fitted to another bike, you can see the cup at the top is flush, then theres a black cover over the bearing and then a nut and a lock ring thingie.

1776

Here is a photo of the schematic for the parts, I just dont want to pay 1400 Euro for the OEM Titanium column. Maybe ill go the 7075

The bearing is OEM (26x47x15) and just fits into the steering cup inside the frame

1777


Ill see what I can suss out ebay wise for Ti, but good to know the local damage. Thanks Ripperton!!

[Kris]

Bit of info for you RIPPERTON, Aprilia confirmed to me the reason they used Titanium for the column over Aluminium is because of strength. The bearings they use are very small compared to the OEM bearing (I thought oem was 26x47x15, this bearing is infact the race bearing) and the OEM is alot larger. Because of the stress on the column they used Ti over Steel.

With larger OEM bearings, alloy would have been fine.

We will make a column to suit OEM bearings and will use 7075-T6 as suggested.

[Little Mick]

Just saw this Kris.

I made one for Oggys Harris last year. We were grafting a CBR front onto his PCRA frame. I made his out of CrMo, but as Danny says, the 7075 should be sweet...

Cheers

Mick

[Kris]

nice one! Ill let you know how we go with it :)