Suspension damping for trail riding
Lee,
How do you like to set rebound and compression on standard trails? Mine are minimum rebound and minimum compression.
Cheers, Martyn
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Hey Martyn,
This is a personal thing. If your bike isn’t bottoming, and it doesn’t feel bouncy, you’re probably fine.
Rebound: I run it almost as fast as it will go, just shy of bouncing back.
Compression: I used to run as little as possible; now I run my bikes almost as stiff as they will go. On my Enduro SL with FOX RP23, I usually descend with the ProPedal at full setting. It feels more stable and controlled than at the soft setting. (Note: I do rocky climbs in the lowest ProPedal setting; it hooks up better.) On my Demo 8 with FOX DHX 5.0, I run the ProPedal around the middle setting, the boost chamber up at 170 and the chamber dialed all the way in for a progressive spring curve.
Read this article: FOX ProPedal and suspension bracketing
Lee – I don’t understand – aren’t you defeating the purpose of your RP23 by descending with your propedal (low-speed compression essentially, right?) set to super-stiff?
Isn’t the benefit of a suspension that actually moves the fact that it will suck up the hits and then allow you to be more stable and controlled??
Comparing apples-to-apples, say you had a rock in the trail you hit at speed and you took two runs at it; one with the propedal ‘off’ and a plush bike, and one with the propedal ‘on’, with a stiff bikes. Wouldn’t the stiff setup provide less ‘give’ and suspension movement (note I’m trying not to say compression) than the plush setup? Wouldn’t this lead to a higher amount of deflection, body movement, shock absorption through yourself, wheels, tires, other parts, etc instead of your suspension?
So confused and genuinely curious about your thoughts on this…
Or are you saying that you ramp up the compression in some scenarios? The compression setting on the Enduro SL’s E-150 fork is a great example. If you ramp up the compression you have better control on a trail that you need to pump a lot, right? You can pump corners, rollers, rocks, etc without wallowing in the stroke of the fork. However the same compression setting on a rocky trail will provide a bumpier, stiffer ride without the fork absorbing the hits from this rocky terrain.
Conversely, a lighter compression setting will cause you to wallow in the stroke of the fork on terrain you need to pump a lot but result in better terrain absorption in rocky trails.
Bottom line is that there is a fine line for each rock, bump, section, trail, area…. you can tune this fine line with compression and with riding styles, yeah?
Anyway sounds like things are well in Lee’s world – good to hear. Rock on.
Brett
Hey Brett,
– You’re right: Every setting is a compromise between ease-of-movement and feel-for-the-ground, plushness and control.
– A Cadillac is comfy at low speed, but at high speed it becomes uncontrollable. A Corvette feels stiff while going slow, but at speed it feels planted and controlled — this translates into confidence and comfort.
– Same with a stiff vs. soft bike. Soft bikes feel great at low speeds, but at a certain speed/intensity, stiffer becomes more controllable. Why? Less wallow, better pump, the bike is more likely to skim over stuff than plow through it.
– I’ve ridden Brian Lopes’ bikes, and they are ridiculously stiff!!! With his intensity, they have to be.
– Even in the full ProPedal setting, a high-speed rock impact will easily blow through the platform. At this speed the bike is plenty plush, plus it’s more controllable than at the low ProPedal setting.
– Different situations do call for different settings, but I try to stay consistent.
– You should pump all trails! The gnarlier it is, the more important the pump.
Braaap,
— Lee
Many thanks Lee, and another question sag 25%?
I’m going to have to order another book as I’ve given the first to my brother. He’s only had a bike for a year but was quite unfit but to see him now after a year a huge diference, your book has given him huge ideas. Oh and I’ve just watched Lopes winning the 4x World Champs in Scotland (recorded on video) He was soooo happy winning that one.
The amount of sag depends on your frame design. 33% is about average in rear, but the range is maybe 25-40%. Check your manual.
Yeah, Lopes isn’t getting any slower is he?
Lee – I understand your cadillac vs corvette comparison…
But for small bumps you aren’t using your suspension to its fullest. Which may be your point. Aren’t you simply absorbing more of this terrain with your body/tires/frame than you would be with your suspension if it were set softer? Why wouldn’t you want to use that suspension more? Isn’t this the idea behind suspension tuning and the fine art of making a suspension that works best for you? One that sucks up the big hits and is still sensitive to the smaller ones without making your steering and weighting inputs worthless?
And to the car comparison, shouldn’t we be thinking more in terms of a baja race truck or something that is off-road instead of an on-road vehicle?
Cadillacs and Corvettes both are driven on-road and a stiff suspension would win-out in high-speed and low-speed situations. This is a given. However, in talking about off-road applications with big-hits possible as well as small bumps, a baja race truck is a better example IMHO. I’ll admit I know very little about these trucks or their suspension setups. but I expect there to be a lot of compliance in the suspension conforming to the terrain given that these trucks regularly take big-hits and suck up many small bumps at very high-speeds. Any footage of baja racing clearly shows this. They would have to find that fine-line in tuning to allow for proper cornering without too much suspension wallow and diving with consideration towards an active suspension on small and large hits/bumps.
So… these vehicles would have to be stiff enough to withstand cornering forces without sacrificing *too* much movement and terrain absorption. You don’t want an oversprung or an undersprung vehicle….
And yeah – (anti-)sway bars and the like come into play with vehicles and there are probably 1000 other reasons why it isn’t a great comparison, but in generalities I’d think it works…. maybe ralley (go Subaru!) is a better comparison… maybe splitting hairs at this point though.
Enough… thoughts?
Brett
Good points bret.
I have Baja racing suspension, from Donahoe Racing, on my truck. It definitely has a good amount of low speed compression damping such that if I hit a bump at 5MPH, for example, it feels really firm/less compliant and I can really feel the truck going over the bump. If I hit the same bump at 30+ MPH, I do not even feel it; I only hear a thump. I think it’s called digressive damping. Allows you to corner with speed (minimal roll) and minimized brake dive.
OK Brett, you smartypants …
1.
Suspension is very complicated, especially at the high end. See above. Baja trucks are insane.
2.
This comes from Mark Fitzsimmons at FOX: The faster your ride, the stiffer your suspension. And, yes, stiffer suspension transmits more force to your body. But faster/more aggressive riders are also stronger riders, and they can handle this.
Fitz says many riders even change their setup over the season. Softer in the beginning, then, as they get stronger/faster, they stiffen things up.
3.
Consider my two motorcycles. One is a Honda CRF450X trail bike. The other is a Honda CRF250R motocross bike. They are both high end, performance-oriented machines. They’re made for different types of riding. The 450X is plush and forgiving and lets me cover lots of trail at a mellow pace with good comfort, but on an MX track or on really rough stuff at a hrd pace, it’s a wallowing beast. The 250R feels stiff and sketchy at low speed, but — dude — if I ride it hard it’s amazingly planted and smooth. Sure, it transmits more force to me, but it does so with great control. When I race 2-hour hare scrambles on a mix of MX and trail terrain, very rough, fully pinned, I race the 250R.
4.
Re: the 450X. When I first got it, it felt sketchy, so I softened the suspension so it would feel planted. Now that I’m more confident and riding a bit faster, I’m back to the stock setting. See #2 above.
Complex!