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  #51  
Old 6 Days Ago
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Quote:
Originally Posted by Jakobi View Post

I'm not sure where I stand..

No suspension setup is a magic pill. No particular bike will make a novice into a pro. It's always the rider who makes the magic happen.

A shitbox can be a good way to limit the abilities of a novice, and reward them for learning technique and applying it. Overweight, underpowered, and limited travel really makes you consider line selection..

On the other hand, a nice setup can really make things feel much more effortless. Like adding another level of ride fitness, without actually being any fitter. The accumulated fatigue that builds after several hours of riding a less than ideal setup can be pretty significant.
Riding a bike well/quickly is about confidence. If you can ride confidently on something with grease in the forks, then more power to you - but most of us will be way happier with suspension that is working as well as it possibly can.

I spent my childhood on old poohbox bikes that had crap suspension even before the oil all leaked out... It taught me a lot of bad habits that still linger - mostly about being stupidly careful (ie: slow) in line selection, but also backing off to stay alive.

Having the suspension set up so it behaves predictably (if not well) is pretty much essential to stop me having flashbacks to being a 13yo on a XL175 having a huge tank slapper...

I was always cynical about how much difference properly set up suspension is, but once you've experienced it, you realise how slow/dangerous poorly set up suspension is.
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Last edited by Spac; 6 Days Ago at 11:55 PM.
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  #52  
Old 6 Days Ago
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Quote:
Originally Posted by Spac View Post
I was always cynical about how much difference properly set up suspension is, but once you've experienced it, you realise how slow/dangerous poorly set up suspension is.
So true. I was always happy with my bikes, tweaked by a well-regarded Aussie tuner, until I was in CA and loaned a JGR/ENZO factory YZ-F 450. I now know when my bike is as good as the OEM compnonents will let it be and have a benchmark. The 450 was insane and changed my whole outlook on things.

To be fair, when you're a strong, fit rider punting a heavy bike with good traction at low speeds in shitty terrain, that last 10-15% of suspension capability means nothing compared to throttle control and other rider inputs.

The opposite is true if you're a 75kg guy on a 500 and you come around a turn WFO in 5th gear and encounter a boulder field.

You only have to look at trials riders' set-up...all gearing, tyre pressure, jetting, clutch actuation, whereas FMX is almost solely suspension, horses for courses.

Jake and Nathan are spot-on, the least adept riders get the most benefit from great suspension. The Pros can ride around most deficiencies in a bike.
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  #53  
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Quote:
Originally Posted by Nutty View Post


Jake and Nathan are spot-on, the least adept riders get the most benefit from great suspension. The Pros can ride around most deficiencies in a bike.
Exactly my point in another thread. A mediocre rider with poor or poorly
set up suspension will get beaten up more, fatigue more and generally have a less fun time than the same rider on a well suspended bike. I know, 'cos thats me!! I hadnt realised till I got good ( better) suspension that it affects everything: handling, braking, fatigue, saving your bacon from 'oh snap!' moments, traction, and of course, confidence.
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  #54  
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Quote:
Originally Posted by Jakobi View Post
I think in any instance, the first setup is only a starting point. Through comparison of static sag, race sag, preload, and feel/feedback then you can dial down and find the sweet spot; the point of best compromise for that particular setup.
Jake, I couldn't agree more, but still think a better "starting point" for a new bike, rider, spring is the rider sag. Especially if the "gumby trail hack" doesn't have the desire to experiment after initial setup. I've never once said that rider sag is the only thing to be considered.

Very few people will take the time to find the optimum setup like you do. This is evident by all the "just ride it" or "suspension is for pussy" type comments that appear in these threads.
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  #55  
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2014 ktm 350 excf

Progressive spring

Static Sag = 38
Rider Sag = 130

How's my spring rate looking as a starting point?
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  #56  
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Quote:
Originally Posted by tonyg View Post
2014 ktm 350 excf

Progressive spring

Static Sag = 38
Rider Sag = 130

How's my spring rate looking as a starting point?
Without knowing KTM350 specifics, it look like too much of both and that winding the spring up would be a good idea, but that the spring is slightly too soft for you.

Basic starting point is that you want about 10% of the total travel as bike sag, and 33% as rider sag. It is only a starting point, as previous comments have explained.
In your case, taking 8mm off the bike say will get you close to the 10%, but will leave yo at 122mm of rider sag, which is more than ideal.
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Last edited by Spac; 5 Days Ago at 04:07 PM.
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Quote:
Originally Posted by Spac View Post
Without knowing KTM350 specifics, it look like too much of both and that winding the spring up would be a good idea, but that the spring is slightly too stiff for you.
I'd go the opposite Tony, I'd be looking for 35-38 and 110ish. I reckon it's a tad too light.

Quote:
Originally Posted by Jeff Slaven


Measuring Free Sag


Using the same measurement points as used for the rider sag, measure the rear suspension sag with no rider aboard. Lift and press on the suspension several times to establish a consistent resting point. The free sag should be 5% to 10% of the total travel. On 12" travel suspension the measurement should be 15mm to 30mm. Linkless KTMS should be 25mm to 40mm.
Quote:
Originally Posted by KTM Manual

Determining the static sag of the shock absorber:

The static sag should be as close as possible to 35 mm. Deviations of more than 2 mm can strongly influence the motorcycle's performance.
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Quote:
Originally Posted by Nutty View Post
I'd go the opposite Tony, I'd be looking for 35-38 and 110ish. I reckon it's a tad too light.
Pete those numbers would be very close I reckon.

I can't achieve those numbers with my current spring.
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  #59  
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Quote:
Originally Posted by Nutty View Post
I'd go the opposite Tony, I'd be looking for 35-38 and 110ish. I reckon it's a tad too light.
Jeez, you were quick - I spotted and fixed my mistake within a couple of minutes!

Worst bit is that it was one of those typos in my internal dialogue. Not sure if this is the product of getting old or insufficient beer.
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  #60  
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Guys, what are your thoughts on the formula below?
(posted by Dwight Rudder on TT)


Quote:
Originally Posted by Dwight Rudder on Thumpertalk
I have come up with a formula that I use for setting the suspension up on my bikes. This info was collected the past few years from several different tuners and applied. I have broken this down into a formula using percentages of available travel so this will work on most any bike. (KTM PDS is slightly different but close). I thought I would share this knowledge with you.

Your shock spring preload should be less than 10mm on linkage suspension but not less than 5mm. You don't want to over preload a weak spring as you will just get a harsh ride that still will allow hard bottoming. I usually shoot for about 5mm preload on fork springs. If you have the right spring.

You can figure your correct sag numbers by using percentages. That way you can get the correct springs for you and your bike. Base these percentages on the available travel front and rear with a variance of + - 3 mm.

Front suspension static sag should be 14% ( available travel in mm X .14 = static sag in mm)

Front suspension rider sag should be 25% (X .25 = Rider sag)

Rear suspension static sag should be 11% of available travel (X .11 = static sag)

Rear suspension rider sag should be 34% of available travel (X .34 = rider sag)

Using these principles you can figure the correct sags for any bike and thus the correct springs without guessing and compromising.

Once you get the springs set correct you can get the forks and shock revalved if need be. I usually like to take 20-25% of the high speed compression out with the correct spring rates. I am an offroad racer / rider.

I usually leave rebound stock or change according to the replacement springs. I usually will change rebound one click per .2 kg. on rear shock. If I go up on spring rate say from a 5kg to a 5.8kg , I will go in 4 clicks. That is a good place to start. After setting rebound and spring sags (and getting correct spring rate installed). I find a G out or a ditch that I can jump into and expect to bottom front and rear at same time. I will back off compression till I am bottom softly front and rear. NOT DRIVING FOOTPEGS THROUGH YOUR FEET OR METAL TO METAL BOTTOMING.. Just bottoming softly. Then I go back in about 2 clicks to compensate for heated suspension. I then will ride extensively to see if I need to go in or out slightly to fine tune. Damping I find is a very personal thing it you take the time to dial it in. I like a plush and compliant suspension but not wallowy. Many times lately I find that I have to go down on fork springs and up on shock spring rates. I weigh 180-185lbs and ride a 2011 Husqvarna WR150. It came with .42kg fork springs. That is what my KTM 525 / 530 had in the front forks. For sure there is a big difference in weights. I tried .44kg on my 525 and the bike would not turn. The bike should settle into the corner front and rear when turning. My bike would not settle. The forks were way off static and rider sag. I was on the cusp whether to go to a .38kg or .40kg. If I were 10lbs lighter I could have used a .38kg. But as it stands the .40kg allowed my sag numbers to work perfectly. 40mm static and 75mm rider. With the correct sag rates the bike is not nearly as tall feeling. Much easier to throw a leg across. Turns perfectly and is very stable on straights. I am very happy with the results. Use the formula and you can get the perfect spring rates for you and your bike. Don't ride the bike till you are satisfied you have the correct spring rates as most shops will exchange unused springs for different rates. If you ride with them they will look used and can't be sold as new. I think you will be very happy with the results if you don't compromise.
https://www.thumpertalk.com/forums/t...king-free-sag/

Last edited by OMC; 5 Days Ago at 09:06 PM.
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