Joined
·
1,479 Posts
Zip-tie in front fork should be banned, because it causes much more problems than bottoming out...
Posts by speedfinn
1 - 20 of 144 Posts
Joined
·
1,479 Posts
Because reaction to zip-tie-position is usually something random like this:
Joined
·
1,479 Posts
Sometimes Dave Moss gives good info, sometimes bad info. That 80% vs 20% is really bad info.
Joined
·
1,479 Posts
First you should understand what is "bottom out", and how long and why and where the front end bottoms out.
If the front end bottoms out, and front end/ front wheel of the bike stays on a straight (or constant) line, bottom out is no problem.
If the front end bottoms out too much/ too long, front end/ front wheel starts to act like a snake, and goes from side to side.
In both cases front end uses 100% of its total suspension travel.
Joined
·
1,479 Posts
Well, then we should first agree if we are talking about some random stock street suspension or stock track suspension or OPs suspension or what...?
Joined
·
1,479 Posts
Zip tie does not tell you where and why and how long front end bottomed out, so do not think of it as a Data Recorder.
Any any reasoned suspension Tech will tell you that.
Zip tie will only give you one and only info: Front end bottomed out somewhere, for some reason, for some totally unknown period of time.
And if you are using Frankenthe3rd's measurement, remember to press down the front wheel in case of top out spring keeping the last millimeters hidden/ to get the actual total length of the front fork.
Joined
·
1,479 Posts
Do you have hydraulic bottom out locks in it or not?
Joined
·
1,479 Posts
Yes, front suspension should always use 100% of its suspension travel, that 100% includes also bottoming out. In ideal situation that bottoming out happens every time when you hit your brake mark and start braking. And depending on how much your bikes front end can carry load (weight shifting + braking force), it gives you a limit how much your maximum brake force can be when you start braking.
If you are using too much braking force compaired to the front end load handling capacity, front end will bottom out too much/ too long and front wheel starts to act like a snake, and goes from side to side.
Joined
·
1,479 Posts
Well, as I said Zip-tie in front fork should be banned, because it causes much more problems than bottoming out...
Joined
·
1,479 Posts
Some random example from reality:
The front end has K-TechDDS cartridges with 125 mm total suspension travel, sag set at 40 mm, 11.5N springs, standard oil level. Pace/ lap time is track record +5 seconds. The front end is bottoming out a few times on every single lap. One set is about 10 laps, and 6 sets per day, so front end bottoms out a couple of hundred times in one track day.
So, what kind of advise you would give to a 2011 S1000RR track only -owner, if the bikes front end is bottoming out ALWAYS when the owner manages to brake with adequate effort?
Joined
·
1,479 Posts
The problem is that most of the people does not understand the basics of suspension, and therefore they do not understand what the zip tie indicates and what to do with the "info".
That is why zip tie is more harmful than useful.
Suspension bottoms out once from a bump and ""THEREFORE" need to adjust their spring / compression or riding style to ensure that it is working optimally"
Simply a stupid idea...
When suspension is working correctly, it should also bottom out. That is suspension basics.
How many times you have crashed right after brake mark? Or in mid brake? Or just before apex?
Front suspension should always use 100% of its suspension travel, that 100% includes also bottoming out. In ideal situation that bottoming out happens every time when you hit your brake mark and start braking.
If you suddenly gain a bit of speed, it usually indicates that you braking ability is also far from ideal.
You could also try to answer to this question:
The front end has K-TechDDS cartridges with 125 mm total suspension travel, sag set at 40 mm, 11.5N springs, standard oil level. Pace/ lap time is track record +5 seconds. The front end is bottoming out a few times on every single lap. One set is about 10 laps, and 6 sets per day, so front end bottoms out a couple of hundred times in one track day.
So, what kind of advise you would give to a 2011 S1000RR track only -owner, if the bikes front end is bottoming out ALWAYS when the owner manages to brake with adequate effort?
Joined
·
1,479 Posts
If you can not answer to a simple question about real life track only bike front end bottoming out:
Then I also recommend you to contact your suspension guy and get his opinion.
For others who may be reading this thread (including the OP):
Take any fast bike/rider; their front end will bottom out a few times per lap.
If they would try to prevent that, they would either have to brake much less, and lose at least a couple of seconds per lap.
Or they would have to stiffen up front end so much, that they would loose too much front end traction, and again they would loose at least a couple of seconds per lap.
That is why Dave Moss 80/20% rules are not a problem for slow riders, or for people who do not understand suspension basics.
Joined
·
1,479 Posts
Well, the only issue/ problem is that you do not understand suspension basics regarding a track only bike. That is why you can not answer to a simple question about a real life situation.
And that is why you do not understand that any fast bike/ rider is always using 100% of the fork travel. And that 100% includes also bottoming out.
The real problem is that your suspension God has told you that bottoming out is not normal behaviour of suspension, bottoming out is dangerous, and you will crash if front end bottoms out. And you believe him, and your faith is very strong. That is why you do not understand that your God has given you bad info.
If you think about some random wsbk or MotoGP bike; why would they not be using 100% of the fork travel? Why would they like to loose in lap time because of that?
Joined
·
1,479 Posts
I hope that some day your ego will give you a chance to evolve.
Are you familiar with data logging? Does logged data tell you anything? Have you ever seen such? Ever analysed data?
Here is real life suspension data graph from a front fork, one lap. The riders pace in this data is same as in Superstock1000 european championship TOP25. So not a MotoGP or WSBK rider, sorry for that... And not from my bike, I'm not that fast, but from a S1000RR.
To make it easy for you, I have marked a red line where the suspension hits the surface of bottom out rubber. After that suspension will compress the rubber additional 0-2 millimeters, if braking force is continous and track surface is smooth. If braking force varies or track surface is not smooth, front wheel will "bounce" a bit back and forth, hitting the bottom out a couple of times in one braking instance. Total length of the data in the picture is about 105 seconds.
Attachments
Joined
·
1,479 Posts
Lateral grip is not needed when the bike is upright. That is why it does not matter if the front end uses 100% of the suspension travel and bottoms out, when you start braking.
And as you can see from the data, that is normal behaviour for track only bikes front end. And you can also see from the data, that everywhere else suspension is not close to bottom out. So when lateral grip is needed, suspension has travel left to react to unexpected bumps.
Take any fast bike/rider; their front end will bottom out a few times per lap/ as you can see from the data.
If they would try to prevent that, they would either have to brake much less, and lose at least a couple of seconds per lap.
Or they would have to stiffen up front end so much, that they would loose too much front end traction, and again they would loose at least a couple of seconds per lap.
That is why Dave Moss 80/20% rules are not a problem for slow riders, or street riders, or for people who do not understand suspension basics.
Attachments
Joined
·
1,479 Posts
As everybody has already noticed, only our own suspension God can give you credible info that your ego approves. He is the only credible source for you, everything else is just blasbhemy in our eyes.
So next time you meet Him, ask Him is the fastest riders from WSBK and MotoGP are bottoming their forks, and how often that occurs per one lap. Do not be suprised if the answer is something totally unexpected/ against your current "truths".
Because you do not understand suspension basics, I also assumed that you do not have any experiense on suspension data logging and analysing. That is why I tried to make the data as simple as possible for you to understand. But no luck...
For other thread readers:
If you have any kind of questions about track only bike front end bottoming out and/or suspension data regarding that, just ask. I'm happy to share the knowledge what I have gained in past ~11 years.
And as I said previously, Dave Moss has some good info and some bad info. Most of hes clients are riding street bikes with stock suspension on road or on track, and that is totally different situation than track only bike. That is why you should always put the info to correct context, and if you do not now suspension basics, it is hard for you to know what would be the correct context.
Joined
·
1,479 Posts
It depens on where you are now and what is your target. That will tell what kind of tools you need to achieve what you are looking for.
Do you want to keep the DDC and test and learn to tune it, or are you going for conventional internals? Do you have the front suspension sensor and datalogger?
What is your budget for front end?
What is your riding skill level? What is your pace? What is your braking ability?
Is the bikes weight stock or is it stripped for track use? What is your weight?
= How much you need load carrying capacity for front end (bike+you+braking))/ what kind of stress the front end have to cope with?
Joined
·
1,479 Posts
Zero-budget? Well, in that case it is quite simple: You just need to always keep in mind that when the front end bottoms out at the start of the braking; there is your front ends limit, it can not cope with any stronger stress than that. So, front end might feel a bit weak, but that is the result of the zero-buget.
It does not matter if you hit the brakes hard, or if you slowly increase the squeez; your front end will bottom out, because in either case it has to carry the load you are pushing on top of it.
And it does not matter if you feel that the deceleration is only 70-80% when the front end starts to squirm a little bit. There is the limit.
If you want to get in to the trouble, just think once "I am braking so softly..." ,"How about..." or "Just a little bit..." while riding on the track, and you will try to do something what your bike is not capable to. You have to first change te bikes capability before you can "Just a little bit more..."
So, know the (zero-buget) limit, and drive according to it. It is very easy to forget it.
Joined
·
1,479 Posts
I do not know your current settings, I do not know how your bike behaves, I do not know what kind of changes you would like to make to your bikes behaviour. Based on that, how could I give any advice on settings? I or anybody else could give you some random lottery generic settings, but they are as useful to you as a zip tie in your bikes front fork or in your wrist.
And related to that: That is why I like data loggers. Because the driver might be lying unwittingly to himself. Data does not lie, and it will tell you everything about the front end if you have the sensor. And the 2D data logger is plug and play, fits any YM (easy to sell), easy to use, it will tell you Everything about the bike, and it is cheap as hell when compaired to its features.
9.5&11.5 is kind of soft for 220 lbs rider. For comparison: I'm about the same weight, 11.5 springs, 40 mm sag, additonal 5 mm front end total travel (K-TechDDS cartridges), and front end (still) bottoms out with maximum braking.
If you want to convert a stock street bike to a track only bike, you need a budget. If you have zero-budget, then you have a mass production stock street bike with mass production stock street bike suspension which is aimed for free spirited office workers riding on streets, and that sets some limits.
But, back to generic settings, step one: Do you know what is a top out spring(s)? And how it works etc?
If you do not, then for example:
Graph:
https://www.sportrider.com/tech/ask-geek-fork-top-out-springs#page-2
Some info:
https://www.sportrider.com/how-do-top-out-springs-affect-sag
Apply full preload setting to front forks.
Lift your bikes front end up to the air. Put a zip tie in to the bikes front fork (Did I just say that!?), lift the zip tie up to the cup, and then press down the font wheel and see if the front fork extends just a bit and retracts.
If it extends then you can use full preload setting without losing the sensitivity of the front end when front end is fully extended. In most cases the top out spring is designed so that it should work up to full preload. But you have to test it to make sure.
If it does not extend, loosen up preload one turn at a time and see when you are able extend the front fork when pressing down the front wheel. Then you know when you start to lose some of the front fork sensitivity when fully extended vs preload setting. It is not a big thing, but nice to know.
Also, press down the front wheel and keep it there, lift the zip tie up to the cup, and measure total length between zip tie and fork bottom. That is the free length of the front fork to be used when measuring sag. It is easyest to measure with vernier caliper.
Joined
·
1,479 Posts
Do you have datalogger and suspension data?
What you have done/ what do you do to avoid bottoming out?
1 - 20 of 144 Posts
