Converting a fox 36 275 to 29. Anyone done it?

[beno]

Hey folks,

As the title says I’m after any info or experience fellow burners have on this. I have a 2017 fox 36 170mm factory fork that was damaged along with my bike in transit overseas just as the world turned upside down last year. The lower legs were damaged with a cracked arch and bent axle. I’ve done a little research online and it seems it is possible but information is in short supply.

I have bought a 29er lower leg assembly(2017-2020 are the same), and the lowers are 10-15mm taller than 275 so I know they will be shorter in travel, just not sure how much. The 2017 fork has a adjustable air shaft, so I should be able to get the travel I want (160mm) to suit the new bike without buying another.

Normally I would just dummy fit it together and see what I need to do, but I’m still overseas and do not have access to my tools or a work space to do it in, so I’m after any insights you guys might have to minimise any mess I may cause playing around with it

 

[The Duckmeister]

Everything else being equal, your stroke length will reduce by the additional length of the new lower. The critical guts of the spring unit are encased in the upper, so the shaft at full extension dictates where the bottom of the fork is. Therefore the longer lower will slide further up before the shaft locates in the end socket; whatever stanchion length is left will be your travel, as thd lower won't go past the base of the crown....

The damper is likely exactly the same unit for both fork sizes, so won't affect anything in a mashup unit.

 

[beeb]

If you plan to "mullet" the bike by swapping to a 29" front wheel as well, just remember that it will raise the front of the bike another ~18mm in addition to the 15mm longer lower legs.

 

[beno]

Thanks fellas, bike is a 2020 giant reign 29 bought 6months into arguments with airlines, freight carriers and insurance companies. It’s pretty basic that’s why this conversion has been on my mind for a while. Ironically my insurance was approved 2 days after buying it . So will have a new bike waiting for me when I get home.

 

[beno]

Ok just did a bit more measuring and so the info is documented, I was measuring incorrectly. I was measuring from the centre of the axle to the top of the seal, but the legs themselves are actually the same length. It’s the dropouts that are in a different location. This is for 2017-2020 forks. Not sure for earlier or later production.

 

[beno]

Well fork is in the bike, there were a couple setbacks, the stantions were a little damaged as well, with slight dents where they made contact with the lower legs In transport. Not something you can see but feel.. fork performed as normal though, no weird noises or burping of oil etc. will monitor them closely the next couple months.

Of course the average rear shock only feels more average now but that’s to be expected I guess. Hunt is on for a 2021 x2 at the right price.