Dialing in new suspension


September 18, 2020, 01:32 PM

How tricky is it to dial in suspension? I got my first full-squish this summer (2021 Polygon Siskiu N9) and I love the way it rides, and the suspension feels amazing except for one thing. I feel like the suspension was tuned for someone about 40-50 pounds lighter than me (I'm a relatively big guy, well over 200 lbs). I couldn't tell you the % sag off the top of my head, but when I hit larger jumps or drops I have to flip my rear lockout to the middle setting (it's a 3-click lockout dial) to avoid bottoming out (which should not be an issue with 160mm of travel F+R lol), plus more annoyingly, pedal strikes have become a much more common issue from riding low.

I currently have no practical knowledge of how to tune suspension except for very basic knowledge of rebound speed adjustment. Does this sound like something remediable, or should I just get used to always riding with my rear suspension half-way locked out?

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XXX
imwjl
Pleasant View Trail Steward

September 20, 2020, 11:40 AM

How tricky is it to dial in suspension? I got my first full-squish this summer (2021 Polygon Siskiu N9) and I love the way it rides, and the suspension feels amazing except for one thing. I feel like the suspension was tuned for someone about 40-50 pounds lighter than me (I'm a relatively big guy, well over 200 lbs). I couldn't tell you the % sag off the top of my head, but when I hit larger jumps or drops I have to flip my rear lockout to the middle setting (it's a 3-click lockout dial) to avoid bottoming out (which should not be an issue with 160mm of travel F+R lol), plus more annoyingly, pedal strikes have become a much more common issue from riding low.

I currently have no practical knowledge of how to tune suspension except for very basic knowledge of rebound speed adjustment. Does this sound like something remediable, or should I just get used to always riding with my rear suspension half-way locked out?

I don't know that bike or what your shock and fork are. Measuring your sag and knowing what percentage is ideal has been helpful for all the types and brands I've had. I tend to like more plush for fork and more stiff or platform for rear suspension unless that's for really long downhills. For the latter I mean real mountains, ski area downhills, or some places near Lake Superior, Brown County etc.....

Keep in mind at times some more plush really helps you with climbing and braking traction.  Also keep in mind the bike geometry. One of our 2 modern 29r bikes has a lower bottom bracket no matter how you adjust things. A hard tail bike we love has a low bottom bracket. Pedal and crank arm strikes from low bottom brackets is just part of darn fun to ride bikes.

If this is all new, maybe being conscious of pedal position is important too. Know to keep them at 3 and 9 (the clock) and to have an outside pedal down for some turns. Know to ratchet your pedals to get over obstacles or through water.

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XXX
augs
President
Board Member

September 20, 2020, 06:21 PM

Not familiar with that bike either.  Or rear suspension for that matter.  But you shouldn't have to ride with it partially locked out.  I'd take it to the shop where you bought it and explain what is happening.  If it's an internet bike, I would go to one of our sponsor shops and offer to pay them to help you; they might do it for free but it's good form to be willing to pay.  There are also innumerable videos and threads online about suspension tuning, if you've got time to try and figure out who knows what they're talking about.

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XXX

September 21, 2020, 04:24 PM

Rear shock is Fox Performance 36 / Float DPX2. The bike is an enduro, but some sources call it a long-travel trail because of the geometry. 160 mm travel front and rear on the 29er.

With respect to geometry: this was probably the thing I paid the most attention to when choosing the bike. For now I'm comparing this to the hardtail cross-country bike I've been primarily riding for the last 6 years - 2014 Specialized Rockhopper. The bottom bracket height is 343 mm (rockhopper was 310 mm) so 20% sag will put it 1 mm higher. So, very, very similar bb height. And I don't believe cranks have gotten any longer in the last 6 years so one should think there should be no significant change in the size of rocks/roots that require you to think about pedal strikes, but it definitely happens a LOT more, usually on trails that I never had to think about before, including most beginner trails in the area.

With respect to riding technique considerations: rest assured I am very familiar with these things. Not my first rodeo.

I am familiar with suspension tuning at a high level from various sources on the internet but would not feel confident doing it by myself due to lack of experience, also because I lack the tools. Mostly wondering whether it's worth the money to bring it to a shop, or to invest in the tools, or to just ignore it and be more cautious with my pedaling.

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XXX

September 21, 2020, 05:39 PM

If you have the sag set correctly and you're still bottoming out frequently then you need to start adding volume spacers. Assuming you have a shock pump, you don't need any other special tools for the DPX2, and you might just need a socket for the fork.

Slow Roll held a couple suspension how-to workshops over the off season last year, so you might check in with them  if that's something you're interested in.

As far a pedal strikes go, a couple millimeters makes a huge difference. Although problem solving through the internet is pretty tough without seeing your bike in person, switching to lower profile pedals or going from 175 to 170mm cranks will help immensely.

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XXX

September 21, 2020, 06:33 PM

And I don't believe cranks have gotten any longer
I'm a dingus, I didn't realize the bike was spec'd with 175 mm cranks, so that's definitely a factor

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