Rebound damping; how little is too little?

Home Forum Bike Forum Rebound damping; how little is too little?

Viewing 22 posts - 1 through 22 (of 22 total)
  • Rebound damping; how little is too little?
  • Premier Icon roverpig
    Subscriber

    So, a month after crashing and breaking my arm I’m still mulling over all the possible causes and trying to educate myself a bit to reduce the chances of it happening again. Obviously it’s mostly a skill thing, but I keep coming back to the issue of rebound damping. It seems too much of a coincidence that, after six months of riding the bike with the controls in the middle and not having a single crash, ten minutes after basically removing all the rebound damping from the fork (1 or 2 clicks from fastest) I’m laying on the ground clutching my arm.

    The crash happened when (after a decent compression) the front wheel skipped to the side and hit a rock that I’d intended to go round.

    I know what too much rebound damping feels like (fork packs down), but how do you know when you’ve got too little?

    hora
    Member

    New forks- Sunday I realised that they packed down so I turned them to almost full fast rebound – behold!

    I still think you should just chill, ride slow, relax and enjoy riding. After one of my falls it shot my confidence for years as I stressed over ‘why cant I do this/that’.

    sideshow
    Member

    You have too little when everything you hit impacts your hands/arms too much. Arguably you could apply that rule to travel or sag too, but assuming you’re not going to change fork and have set sag appropriately (like 10-30% depending on what manufacturer recommends) then you can apply it to rebound. If you *still* bottom out the fork setting up according to those rules then you are an aggressive rider and need to run less sag. I think?

    Another rule of thumb, if you stand by the bike, hold the bars and pump your forks quickly, the rebound should come up just a fraction slower than you naturally bring your arms back up. If the bars are kicking your arms up faster than you are pulling them up yourself then that’s too little rebound.

    Premier Icon roverpig
    Subscriber

    Yes, relaxing, chilling and just enjoying being back on a bike is the first priority (and can’t come soon enough), but it bugs me that I don’t really know how to set up my suspension properly.

    Looking around online and in books there is lots of stuff on how to set the sag, but discussions of rebound damping just seem to stop at what it is with very few tips on how to set it properly.

    I’ve tried riding the same loop with different settings, but I’m not really sure what I’m supposed to be looking for. I’ve tried riding over a ladder, but couldn’t make any sense of that. I’ve tried bouncing it and seeing if the front wheel leaves the ground, but found that pretty unreliable too. So, I tend to just stick the rebound knob somewhere near the middle and ignore it. In fact, this was my first experiment with an extreme setting and it didn’t end well πŸ™

    Premier Icon Northwind
    Subscriber

    roverpig – Member

    how do you know when you’ve got too little?

    It breaks your arm.

    OK, more serious, too little rebound just feels like a lack of control to me, everything gets pingy and overreactive. If it feels like it’s on springs, then something’s wrong.

    sideshow – Member

    If you keep bottoming the fork out after that then you are an aggressive rider and need to run less sag. I think?

    Mmm. Well kinda. Really what it means is you need to change the spring rate. But with air springs and limited tuning that ends up also meaning less sag. But it’s not really less sag that you’re after. Ideally what you want is the sag you want and the spring rate you want but that’s not so easy.

    Rockhopper
    Member

    The range of adjustment is usually fairly limited so the chance of getting it set so that’s its actually dangerous is slim. Its the same with motorbike shocks (unless you go for proper race kit that is).. its all to do with liability issues.

    legend
    Member

    Rockhopper that’s not right, pretty much every fork I’ve ever seen can be setup to go into full-pogo stick mode.

    Ecky-Thump
    Member

    I tend towards “as much as possible without it packing down”

    Premier Icon Northwind
    Subscriber

    legend – Member

    Rockhopper that’s not right, pretty much every fork I’ve ever seen can be setup to go into full-pogo stick mode.

    Likewise you can set every modern Rockshox I’ve used so that it rebound at snail speed.

    Premier Icon roverpig
    Subscriber

    It breaks your arm.

    πŸ™‚ πŸ™‚ πŸ™‚

    OK, more serious, too little rebound just feels like a lack of control to me, everything gets pingy and overreactive. If it feels like it’s on springs, then something’s wrong.

    On springs? Yes, I think that’s a pretty good description of how it felt.

    Just after changing it I wend down a straight chattery section of trail. No big bumps, but fast with lots of small rocks. It felt much more like it was on springs, but in quite a good way and although it didn’t feel very smooth I was actually going faster down that section than usual, so was quite happy with the change. The problem came when it had to deal with bigger hits. I guess that makes sense. Fast rebound will be great for lots of small fast hits as the form wont pack down and it isn’t moving far enough to really knock you off line. But on bigger hits you might lose traction for a bit after the hit as it bounces around a bit.

    I’m still not sure how to get it just right, but maybe starting in the middle and trying small changes might be safer than banging it to the extremes.

    Set the rear first by dumping your weight on the saddle like a sack of spuds and seeing what it does. Start with little enough rebound that it compresses, overshoots then drops back to ride height, then add one click of rebound at a time until it no longer overshoots. Once you find that point, go back one click.
    Once you’ve done that, set the front just slightly quicker by bouncing all your weight straight down into the pedals (either hop and land flat if you can, land flat off a big kerb, or simply actually jump off the pedals and stomp back down onto them). The bike should compress at about the same rate at both ends and by about the same amount, but the front should rebound at least as fast, or slightly faster. It can be hard to judge, so get someone to watch, or ride around in front of a big window and watch your reflection.
    If it’s a hardtail, set just enough rebound damping to stop the bars feeling like they ping back at you, or just enough to stop the compress, rebound, overshoot, bounce feeling when you go off a single bump like a kerb.
    Better to err on the side of faster at the front and slower at the back to keep the front end up and the back down after big hits.

    fr0sty125
    Member

    Firstly I’m no expert on this and it is one area that I’m still getting to grips with.

    But it could be related… For example if you were running a stiffer spring, fast rebound then it probably would feel supportive and responsive going very fast over small repeated stuff with the fork staying composed in the first part of its travel. However if you took a big hit then it might just rebound like a pogo stick.

    I think it is said that for a set rider only 2 or 3 clicks of rebound out of the full range are actually useful.

    amedias
    Member

    It can be a very personal thing too and will also vary by bike, shock, travel etc. I know I have different settings on most of my bikes, I like the rebound set a fair bit quicker/slower just through differences in the way they handle and the way I ride them.

    Ask a dirt jumper and you’ll get a very different answer to an XC racer or a DH rider etc.

    Most of the advice above is good/in the right ballpark for starting points but the only way you’ll find out what works for you and on your bike is trial and error.

    More importantly, although this may be the hardest bit to do, you need to try and get the idea out of your head that the bike caused your crash, otherwise you will forever be worrying about setup and thinking every failure/crash can be fixed with a tweak this way or that, ultimately it comes down to you, and learning the bike, changing your rebound setting may have contributed but only in so much as it was a *change* you were not used to, not necessarily because it was a wrong/dangerous setting, it just wasn’t what you were used to and consequently you hadn’t adjusted.

    Hope you heal up quickly πŸ™‚

    daveh
    Member

    Set it to one extreme, learn how it feels. Set to the other extreme, learn how it feels. Move inwards until you feel neither! If you push down hard on the bars, then unweight your hands, you’re looking for it to come back up fast but not to overshoot by more than one cycle (Google over damped, critically damped and under damped for explanation).

    Premier Icon jairaj
    Subscriber

    How little is too little? Front end will loose grip and composure as its bouncing around in mid air a lot more and will feel much less compliant. Arms may get tired quicker than before. In extreme case front will feel like its trying to buck you off the bike especially on bigger hits.

    Your average trail has a verity of bump sizes and frequency so the rebound setting will always be a compromise. Set it for the chattery bumps and you’ll have less composure on the bigger hits and vice versa.

    Where on the compromise line you sit is a personal choice. Sounds like you have an idea what turning the dial does so its simply a matter of getting out there and trying out different settings and see what works for you.

    I personally prefer a slower rebounding fork so on the bigger drops the front stays composed and less likely to buck me off. I also like the way it stays more compliant over rooty sections giving more grip and confidence. There are not many rock gardens where I live so the fork does not pack down much with the slower rebound. But I can understand if someone else doesn’t agree with me.

    gonzy
    Member

    New forks- Sunday I realised that they packed down so I turned them to almost full fast rebound – behold!

    you’re not having much luck are you…. 😯

    leaving mine in the middle works for me…i may tweak it a click or 2 either way depending on where i’m riding but generally it stays in the middle

    Premier Icon Northwind
    Subscriber

    What this thread needs is a CCDB and a pair of R2C2 Boxxers- exactly the same number of correct settings, and 10 bazillion wrong ones.

    Premier Icon The Pinkster
    Subscriber

    after six months of riding the bike with the controls in the middle and not having a single crash, ten minutes after basically removing all the rebound damping from the fork (1 or 2 clicks from fastest) I’m laying on the ground clutching my arm.

    Can I suggest that you set the rebound back to the middle and increase it by small increments until it feels slightly too fast then back it off, rather than doing it in one big leap.

    Rebound is a very personal thing and what works right for one may be horrible for another so it’s worth spending a bit of time experimenting and finding what works for you.

    jamesdippy
    Member

    Oh the joys of knobs and twiddly things !!

    Just my thoughts but i really dont think your injury was rebound related buddy, just one of those things.

    Best way to setup rebound is exactly what some others have been saying. The fork should follow your arm back up when compressing it. Remember the whole aim in traction and the wheel to stay tracking the ground

    Try finding one big root or bump in a track. Try rebound fully one way, ride it. Feel what it does. Then go the other way, repeat. Then narrow down to halfway and then do the whole “bracketing” theory to get the final adjustments. Dont worry about fine tuning clicks, one or two clicks dont do much in the grand scheme of things.

    Feel for packing down or over springy as common rebound problems

    fr0sty125
    Member

    What this thread needs is a CCDB and a pair of R2C2 Boxxers- exactly the same number of correct settings, and 10 bazillion wrong ones.

    If only someone could make a cheap trail fork which had high and low compression adjust, high and low rebound adjust with a fairly linear spring…. SR Auron?

    sideshow
    Member

    Northwind is right to correct me btw – when I say sag I really mean spring rate as I have never set these separately from one another myself πŸ™‚

Viewing 22 posts - 1 through 22 (of 22 total)

The topic ‘Rebound damping; how little is too little?’ is closed to new replies.