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Front wheel bearings for Tech Fork


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  • 3 weeks later...

Quick update on this topic:

I received my Tech fork (see above post) and I found a cheap Gas Gas front hub with rotor on eBay to experiment with setup without having to use the front wheel of my current bike.

Bearing wise, I got a pair of cheap 6004 (20 x 42 x 12) to accommodate the 20 mm Tech axle (instead of the 25 mm from the Marzocchi fork axle).  The 6004 are 3 mm wider than the stock 6905 (25 x 52 x 9) bearings.

As expected the 6004 bearings stick out from the hub by 3 mm on each side:


When mounted in the fork:


There are three problems with this approach:

  • The axle now sticks out by 6 mm (2 x 3 mm from the 6004 bearings) which also means 6 mm less thread engagement on the left side fork tube, which can't be good.
  • The wheel is offset in the fork on the right side by 3 mm (not sure how this affects handling)
  • The brake rotor is offset by 3 mm to the right side, requiring a spacer to put it back inline with the caliper.  Spacers (and longer bolts) could be used on the caliper side, but that's extra parts that will need to be dealt with every time I take the caliper off)


So, the ideal is to get 20 x 42 x 9 bearings either the 98204Y (which are hard to find especially in 2RS and $$$ - like $75 a pop) or, per benbeta23 recommendation get some B20-157 bearings.  The B20-157 are easier to find (well not in the USA even tho these are products from a US company!) and pretty well priced at around $10 a pop).

Here is what is looks like with the B20-157 bearings:


And it all lines up with the caliper almost perfectly (it's offset by 0.4 mm to the right but that's an easy fix).


Before I can get in on the bike I need to get an internal spacer.  I might have to make my own because since Ga Gas uses 6004 bearings on the bikes with the Tech fork, it means that they must be using a different front wheel hub for these fork.  

I'll keep updating this post once I get it all working.

Thanks again everyone for the help.


2018-11-19 - 12 - Hub rotor spacers.jpg

2018-11-19 - 08 - Hub in Fork with B20-157.jpg

2018-11-19 - 06 - Hub in Fork with 6004 bearings.jpg

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