[PhillipJ]

I've got a new-to-me 2020 Reign 29 SX and it's pretty good other than getting hung up on bumps sometimes. I'll roll through some roots and most will be fine but one or two will really catch the back and slow me down a lot. One on trail I thought I was going OTB because it hooked on something so bad I got thrown forward but the bike is so loooong that it was fine.

Is this a common thing? I have not read anything of anyone else having the problem. I'm hoping it's shock setup (the OEM DHX2) but I'm not sure what to adjust. The rebound is 18 from closed which is on the faster end of what the Fox setup doco suggests and compression 16 from closed which I think is about the middle of what Fox suggest. The stock 450lb coil seems about right for me at ~85kg ready to ride.

I'll try slowing rebound a little to try to skip over holes rather than drop into them but won't get a chance to ride that for at least a few days.

Any ideas that don't involve buying a different shock?

 

[WhatsUpcountry]

I'd first suggest trying to mitigate the problem by weighting the back end less when these things occur. As far as setting go, if your goal is to go faster then add compression and / or go up a spring rate.

 

[PhillipJ]

You think it's just bottom out? A stiffer spring probably is worth trying but I'm not that heavy for being on an XL frame and not particularly fast so it seems odd that I'd need more spring.

 

[Jayem]

High speed compression is possibly how you might skip over the holes rather than dig into them. I say possibly because it really depends on what is going on here. It's probably unlikely that it's your rebound causing the problem, given that your rebound is pretty light. A stiffer spring might help the high speed compression circuit activate better over the sharp-edged bumps, but then you end up over-sprung and it's harsh because of that (so it'd be fine if you weighed 30lbs more). Sometimes you can adjust the high speed compression "knee", where if you increase LSC, it will help the HSC open up better on those roots when you are traveling real fast and slamming them hard. This will make them harsher at lower speeds though.

Is it "kicking" over roots and sharp-edged bumps? Is it only doing this over multiple bumps in a row?

 

[PhillipJ]

It seems like it's happening at random so I'm assuming it's just when I hit a larger root. Part of the reason it feels random might be the travel imbalance, 145mm at the back and 170mm up front (w.t.f Giant? Just make it slacker and run a 150 or 160 fork) so the fork just absorbs everything and the hit at the back is unexpected.

It's definitely not harsh and terrible over every rough section, it's like something grabbing the back wheel out of nowhere.


Just typing that makes me think maybe I do need more spring. If it was too much HSC it'd be feeling harsh on more bumps I think. There's 400 places in NZ to buy Rockshox and Cane Creek springs but to get a Fox I need to go via a physical shop or get it from Australia.

 

[minimusprime]

It doesn't have anything to do with the travel imbalance imo... it sound like a front/rear compression and rebound imbalance, and too little compression damping in back. Without knowing more about your setup, my gut reaction would be to increase compression damper in back. I'd run LSC slightly tighter then HSC. For example, LSC -7 to -8 out from closed and HSC -11 to -14.

It also sounds like you're a touch undersprung tbh, and if you aren't running enough pre-load, that could be a contributing factor. I'd suggest getting a sprindex coil spring so you can adjust coil rates and find what works, the fact that the sprindex has a touch of progressivity to it will also help.

What are you full bike settings, including fork Comp/Reb?

 

[Jayem]

It seems like it's happening at random so I'm assuming it's just when I hit a larger root. Part of the reason it feels random might be the travel imbalance, 145mm at the back and 170mm up front (w.t.f Giant? Just make it slacker and run a 150 or 160 fork) so the fork just absorbs everything and the hit at the back is unexpected.

It's definitely not harsh and terrible over every rough section, it's like something grabbing the back wheel out of nowhere.


Just typing that makes me think maybe I do need more spring. If it was too much HSC it'd be feeling harsh on more bumps I think. There's 400 places in NZ to buy Rockshox and Cane Creek springs but to get a Fox I need to go via a physical shop or get it from Australia.

That sounds a lot like packing, possibly HSR too heavy, but that's usually a rare problem to have, because you can usually open LSR if you don't have a HSR adjuster, to at least not do that, although the chassis movement/control gets pretty bad.

 

[PhillipJ]

There's no high speed adjustment on my DHX2. I'll try less rebound and more compression next time I get the chance to ride. I don't think it's packing but it's easy to try.

 

[PhillipJ]

Went from half a turn of preload to one and a half turns and the problem is gone, at least on the trails I have access to at the moment.

I think that means I'm a little under-sprung and the problem will likely resurface on faster and rougher trails. Sprindex is a little cheaper than a Fox SLS so maybe I'll go that way.