Volume reducers for rear shock on Jam2 (Fox DPS)?

[sdcoffeeroaster]

Almost every review of the Jam2 comments on the rear suspension as not having enough mid-stroke resistance (too soft). I think I've noticed this as well. It's one of the reasons I get occasional pedal strikes too. I've tried increasing the pressure but that just limits the overall travel. Many of the reviews mention using volume spacers to help with this. Seems like that would mostly stiffen things up at the end of the travel. Has anyone tried using volume spacers in the back shock yet? The comments I've seen are on both the Rockshox and Fox rear shock so it seems to be a characteristic of F.O.L.D. suspension design. I have the Carbon Jam2 which came with Fox suspension component and I do have volume spacers to try. Thanks

 

[steve_sordy]

The use of volume spacers is a standard and easy thing to do. I've done it on clockwork bikes with a Fox shock and I didn't even have to remove the shock from the bike. It took me ten mins in the garage the first time because I was going slow and careful, but I did it trail side in five mins later the next day. I went for the smallest spacer 0.2 cu in first, then tried the 0.4 cu in medium later, but it was too much. I didn't bother trying the large 0.6 cu in spacer.

The effect is dramatic! I got the same %sag with less pressure, and I used less travel on drops known to me, but without it feeling harsh. It only went harsh when I used the medium sized spacer.

Make sure that all the air is out of the shock first by pressing in the Schrader valve nipple, don't just rely on the shock pump deflate button. If there is any air left in, you wont be able to unscrew the barrel. Take extra care to do the whole job in an ultra clean manner. When I swapped the spacers trailside, I must have got some muck in there, because at the next service the stanchion was scratched.

My riding weight is 14.5 stone (92kg/203lbs)

I am planning to tune the air volume on my RockShox Deluxe R Debonair. Being Rockshox it uses rings instead of spacers for the Fox. The Fox spacers clip on, but the rings are like elastic bands and the shock needs to be removed for installation. When I last did a Rockshox shock, I added three rings and left an extra two on the barrel. That was to enable me to add them later without having to remove the shock. But I never had to do so. They are red in colour and they did not look out of place. My only concern was that being on the barrel might stretch them over time so that they would be too loose to then properly fit inside. But I had planed to possibly use them very soon, I was just too idle to remove them when I realised that I didn't need them.

PS: If you decide to remove the shock, make sure that when you refit it, use threadlock on the shock mounting bolts because they can come loose even if torqued up properly!

 

[sdcoffeeroaster]

Thanks, all good information. I'm only about 145 lbs and have the Fox suspension versions, only found on the Carbon version of the Jam2 in the States. I've changed the seals in the one on my Giant so I'm pretty familiar with disassembly. I'll probably try the smallest one as suggested. I tried one spacer on the front fork and decided I liked it with zero. It was a 140mm fork but is now 150mm (changed the air shaft). I've not had any issues with the shock bolts coming loose and check the torque on a regular basis. Ebike maintenance is several times higher than a conventional bike and if you're not mechanically inclined you either spend a fortune with the dealer or learn very quickly. Fortunately I was a motorcycle mechanic and later went back to school to get my mechanical engineering degree which all helps. I often wonder how less mechanically inclined people ride mtn bikes. But I do see them break down a lot more because of the lack of maintenance.

 

[HikerDave]

Almost every review of the Jam2 comments on the rear suspension as not having enough mid-stroke resistance (too soft). I think I've noticed this as well. It's one of the reasons I get occasional pedal strikes too. I've tried increasing the pressure but that just limits the overall travel. Many of the reviews mention using volume spacers to help with this. Seems like that would mostly stiffen things up at the end of the travel. Has anyone tried using volume spacers in the back shock yet? The comments I've seen are on both the Rockshox and Fox rear shock so it seems to be a characteristic of F.O.L.D. suspension design. I have the Carbon Jam2 which came with Fox suspension component and I do have volume spacers to try. Thanks

I’m not a huge fan of progressive suspension but I had to go up a couple of volume spacer sizes on the aftermarket Fox Factory DPS for my Haibike SDURO and it helped a lot with pedal strikes; more than I expected. I added the volume spacers to avoid bottoming out at the pressure that felt and ride best; I was surprised that it helped as much as it did when climbing moderately steep rocky trails where the suspension sags more. It’s an easy enough job to change the spacers that you can just swap them out in small increments until you get it right. The only tricky part is making sure that you air down the negative chamber.