Suspension for a layperson

Hello all,
I'm trying to make sense of this whole suspension, white magic, stuff and I've no clue what to buy; springs, cartridges, valves, oil etc..

Been riding a long time (street) but am now exclusively at the track and would like to learn and get a little quicker/confidant on the track. From what I can gather suspension is No. 1 to make this happen. Bit embarrassed by my lack of knowledge in this area and would like to make an informed decision about what upgrades, if any, I should make.

That said, is there anybody out there that has something I can read/video on YouTube I can watch, to learn the fundamentals of the components that go into a fork? For example, what is a cartridge? Is that the same as a fork spring?

I see all these bikes for sale ( I'm looking to buy) and I don't really know what I'm looking at.

If I bought a stock R6 or a 636 is the stock suspension so bad that it needs changing if I'm on the quicker side of the average intermediate track day rider?

Thanks for reading.

Any information/knowledge would be warmly received.

Thanks,

 

"Race Tech Suspension Bible" (check Amazon for the best price) Long but easy read explaining the basics and fundamentals of suspension and chasis setup. Best investment I ever made after farting around in the dark doing all my own suspension work for the last 40 years.

 

Cartridge is inside the fork and holds all the valves. The spring and cartirdge are seperate pieces.

 

When it comes to the R6, you can go pretty damn quick on the stock suspension. There are plenty of people mid pack or higher in club racing that are still on stock suspension.

Can't say anything about the 636, never rode one.

 

An assembled fork cartridge including spring. when u buy new fork cartridges, u pretty much get 2 of these, with or without springs.


Disassembled cartridge with fork:

Top to bottom:
- Fork cap & rebound needle
- Fork outer, tube, and lower
- Preload spacer (white part) & fork spring
- Damper rod, cartridge body, and compression valve & holder


the damper rod removed from the cartridge body and the rebound valve stack disassembled. the rebound valve bolts onto the right end of the damper rod

 

To add to the above post: the spring supports the weight of the motorcycle and rider and keeps it with in the range of the suspensions movement. It adsorbs energy during suspension compression and returns it during decompression. Heavier riders need a heavier spring, aggressive riders might need a heavy spring. Springs absorb energy and then return it. Think pogo stick. Boing boing. Think 1960's Cadillac on highway expansion joints, fricking thing looks like it is sailing in the Pacific. Got spring but not enough damping.

The cartridge or any other type of valving system (dampening rod, etc,) are used to control the entry or return of energy from/to the spring, this is damping. By forcing oil thought a resistance, damping is created. Energy that is trying to compress the spring is also trying to force fluid through a restricted hole, instead of energy being transferred to the spring it is converted by the "damping" into heat. A cartridge adds a bendable cap to the resistance offered by a fixed hole and can be altered to better suit the requirements. This is (modern) valving. Damper rod forks use only a hole (1960's tech) cartridge forks (1970's+ for select racing models) offers more control over the damping of the movements by having bending "shims" than can be changed to alter the damping curve.

IT IS NOT MAGIC. Just physics with lots of variables. Having a basic understanding of this is awesome even when you pay someone else to fix your problem. At least you can speak the same language, almost.

 

I recently saw a similar topic wherein someone recommended the "Suspension for Mortals" video series on youtube. I'm working my way through it to brush up, but I think its a good starting point as well.

 

I'm a noob to being a technical expert on bike specs. Getting a 2015 R6 that will become my track bike. I'm 6'6" 220 without gear so pretty big for the bike. Am I gonna be okay on stock forks or should I look to at least upgrade the springs? Or will doing just the springs do more harm than good so look for a set of used forks that are already set up with carts etc?

(Done one track day so far and was riding slow/mid intermediate pace by the end of the day on a bone stock 04 R6 with questionable suspension.)

 

upgrade the springs....most springs in stock forks are meant for 150-170 lbs roughly.

 

I do not get what it's so magical about suspension... You need springs set up for your bike and your weight. Whatever bike you get, you start with springs. Then, you need valves to control the flow of oil, in order to control the speed of the spring's compression and rebound.

Bikes are manufactured to suit the greater average of riders. So generally, they are not perfectly set up perfect for anyone.

Once you know what bike you are getting, year, brand, model, etc... Put yourself on a scale and remember that number... Go to a suspension calculator and enter your bike's brand, model, and year, enter your weight and voila!!!! It gives you the springs your bike comes with and the springs you need for your weight.

Generally, you can adjust compression and rebound as long as you don't have to change the springs too much.

Do your homework first! The suspension is only part of a great handling motorcycle. Take into consideration geometry numbers. Some bikes like to be on their nose a little with a longer than stock shock... Other bikes like to be raised front and rear... Consult a Suspension expert on geometry settings for your bike year, brand, and model... See if there are limitations to adjustment of stock suspension components, or if it makes more sense to upgrade components.

The suspension is NOT obscure, magical, art... It's more like mathematics, you do the right calculations and you be good to go.

 

Ballpark idea on how much springs and labor for installation would run me? & what brand springs would yall recommend or are they pretty much all the same?

 

Hence my asking questions to people who know more than me lol
I've already done some research with Racetech's suspension calculator as far as spring rate. Idk if I can afford the 2k+ for full fork rebuilds atm tho and don't really know if I need that much for my riding pace. That's why I'm bugging yall

 

Bypass,

Where are you located and what track do you typically ride at?

IMHO, while many good guys can rebuild your stuff and work with you, it really is helpful to work with someone that goes to your track and helps you set up. In my experience, if you paid for a rebuild, the tuners will help you setup at no or minimal additional charge. Once you get a bit comfortable and start explaining what is happening, a few clicks and adjustments can easily make you 1-3 seconds faster per lap as it will increase your confidence.

I always seemed to buy used bikes, that usually had quality suspension components, and I just had to pay for revalve/springing, etc.

The good news is, R6's have a known good area for the geometry setup, so you should be able to quickly get in the ballpark with your tuner.

 

Back stateside I'll be located near Fort Campbell KY. So far only done one track day at tally. Huey from MarMo was there that time.
Other nearby tracks that I'm aware of are NCM, Barber, & I believe CMP isn't TOO far of a drive. NCM is definitely the closest so I'll probably be riding that and Barber the most. Tally was quite fun though so might go there 1-2 times a year if I feel like destroying tires.
I know Huey's a good guy and runs a solid shop. Had them check out the bike I'm buying for me the other day actually. Hadn't asked if they do suspension or not yet though.

The whole feedback thing is another area I'm gonna have to learn too. I only had about a year and a half of riding under my belt when I went to tally. I got bumped to intermediate end of the day but I was going faster more by watching and replicating fast people than by being actually good. And let's just say being a big guy finesse has never been my strong point so I've learned the hard way so far

 

What is the bike in question?

Replacing springs is about $100-$120 for the springs. Full service, oil seals and bushings, on forks off the bike is about $100-$150
If you want full Race Suspension you can buy used forks with all the expensive race parts installed for $600-$900 (about 1/2 retail)
If you want new race parts in your forks from a race shop, then yeah, it's going to cost you the retail price...

 

2015 R6

 

Hi all,
I've watched a number of videos including the suspension for mortals (thank you), and I did a quick check of my front end with a zip tie. I was curious what my stick-tion was. I pushed down on the bars and put a zip tie on where the fork settled and then pulled up on the bars. I was expecting a big gap but was surprised there was only a 2mm gap. I thought 'great' I have no stick-tion, but then I thought maybe the forks weren't extending at all when I pulled up.

What I think I did identify is that I have no free sag. In other words, when I pull up on the bars, the forks don't extend. At all.

My question is: when you pull up on the bars of a well set up suspension, should the forks freely and smoothly give 10-20 mm (depending on the bike etc.) of free sag?

Notes on the bike: It's an 06 gsxr 1000. Last year I sent the front and rear to Traxxion Dynamics. They did something to them. (Little embarrassed I don't know exactly what). Not sure if they changed the springs. I'm going to give them a call and ask they did. I don't think they did anything wrong (just want to make that clear), but I'd like to know if they did change the springs.

Again, I appreciate all responses and answers. All advice will be greatfully received.

 

Not really. A 220 lb rider on an R6 doing his first track day and a 150 lb racer at lap record pace may need the same springs. Their sag numbers will be entirely different. Spring charts are OK as a rough guide for street bikes, but not really relevant for track and race duty.

I couldn't tell you what Xavier's sag was, but I know what springs we used and if I went by a spring chart, he'd be bottoming out the forks everywhere. Also, some tracks like more spring. Barber and Daytona being two that come to mind.

 

These videos are pretty helpful


http://feelthetrack.com/free-vidoes/ustream/

 

+1

I don't remember a suspension guy ever measuring sag on our stuff, maybe on mini's, but not big bikes.