Sachs fork spring increments

[swazi_matt]

I currently weigh 80kg without kit and at my current weight i think i need to go up a spring. Now i am Trying to work out how much weight I would need to loose to have the original springs work optimally. My weight should be about 5-6kg less than it is and it should not be too much of an effort to get there
I am not an aggressive rider, but ride a lot of rocks and I think I am currently hitting the hydraulic lock on the bigger rocks making it feel harsher

Basically what is the bracket for each spring rate, up a rate for 10kg, 20 kg, 5kg?? Or does it not work like that?

What springs do I have stock and what is the next one up. Are there crossover options available? What is a set of springs going to cost?

 

[bchatt]

I would sayat 80 odd kg you would be right in the center of the "stock" springs range.
What are your sag figures? If you have a (rear) race sag of around 100 - 110mm, and a free(unloaded) sag of around 25-30mm, your spring is the correct one for your weight. The front is harder to measure (fork stiction and where you sit/stand on the bike make measurements "not reliably repeatable"), but, a race sag of around 60mm is where you need to be.
Are you using all your fork travel - maybe too much oil?

 

[gg3]

Hi ,I have just put .48 fork springs in my 2010,up from .42.I am 100kgs.It made a HUGE difference.Dave from STM sorted me out,I could have gone up to a .5kg but not being fast stayed at .48.

 

[Jakobi]

Hi ,I have just put .48 fork springs in my 2010,up from .42.I am 100kgs.It made a HUGE difference.Dave from STM sorted me out,I could have gone up to a .5kg but not being fast stayed at .48.

Fanstic! I am 75kgs nude and carry an easy 15kgs of riding gear (prolly closer to 20kgs). I have a set of TTX inserts coming for my 2010 and have also arranged springs through Dave at STM. He measured the Sachs .42's to be closer to .43 and has sent me a set of .46 springs to work with.

 

[swazi_matt]

I would sayat 80 odd kg you would be right in the center of the "stock" springs range.
What are your sag figures? If you have a (rear) race sag of around 100 - 110mm, and a free(unloaded) sag of around 25-30mm, your spring is the correct one for your weight. The front is harder to measure (fork stiction and where you sit/stand on the bike make measurements "not reliably repeatable"), but, a race sag of around 60mm is where you need to be.
Are you using all your fork travel - maybe too much oil?

Those are pretty much what my sag settings are but I still think I could go one up. What is one up from .42 ... .44?

@jakobi firstly ttx?? I hate you! So at 75kg you going up to a .46, should that then also apply to guys running sachs in sachs (sheep in sheepskin)?

 

[bchatt]

Hi ,I have just put .48 fork springs in my 2010,up from .42.I am 100kgs.It made a HUGE difference.Dave from STM sorted me out,I could have gone up to a .5kg but not being fast stayed at .48.

Wow, out of interest, what sort of front sag do you end up with?
What do you have in the rear?

 

[Jakobi]

Those are pretty much what my sag settings are but I still think I could go one up. What is one up from .42 ... .44?

@jakobi firstly ttx?? I hate you! So at 75kg you going up to a .46, should that then also apply to guys running sachs in sachs (sheep in sheepskin)?

Yeah I know... TTX pfft.. Hahaha! It worked out cheaper than a new bike. LOL

Technically one rate up from .42 is .43 but this is a very subtle change for a considerable amount of coin so most will step up 2 rates. I think you can then run one of each to achieve the same inbtween rate anyway.

I'm also moving up from a 5.2 rear to 5.4 just to take a little more preload off the back end. Daves theory is that you want to run minimum preload to achieve the correct sag. In theory I thought I'd go 5.4 rear and .44 front for my weight which works if you base the stock balance to be right, however Dave feels these bikes balance out and handle better with a stiffer spring in the front (read are under sprung in the forks from the factory).

I haven't got mine yet so can't comment on the outcome, but he has alot of experience in setting bikes up and I trust him in his info.

 

[STM Suspension]

Wow. I'm busy at work for a bit and people say all kinds of stuff about you!

Yeah, Matt, I'd go up on the shock. Forks, too. Probably about the 0.48 and a 5.6 would work pretty good. It's all personal- and that's what I think about all the time- how to get that person's bike to work good for them- so for sure there's some overlap- it depends on a lot more than just kg's. But those spring rates are pretty spot on for where you are.

(I'm about 82 kg's standing here, and I'm thinking about putting 0.50's in my fork- sure, I've got some on the shelf to play with so it's easy, but maybe the spring works a little different/does a little more than people give it credit for... I think you'd be surprised.)

Add: I'm currently at 0.48 in my fork and a 5.6 on the shock-

 

[gg3]

Wow, out of interest, what sort of front sag do you end up with?
What do you have in the rear?

Front race sag 50mm.The new springs were a little longer than stock.Had a ride last weekend & backed the compression off 3 clicks,even better.Now here is the messed up bit.Checked the rear before riding & got 50mm sag & 127mm race sag,huh!!I don't remember setting it up like this?Anyway,got a drift out & wound the hell out of the preload.As my riding buddy said "keep winding,your a fat bastard",didn't bother being too accurate on the measuring,rode all day & it felt way better.Steered & cornered sharper & more stable.Checked the measurements tonight & I have 12mm sag & 80mm race sag?Have I gone too far on the preload,but it felt real good?

 

[bchatt]

Oh well, if it feels good - it must be right. ..... no, hang on, I can think of a few things that feel very very good but are very very wrong....

 

[gg3]

Oh well, if it feels good - it must be right. ..... no, hang on, I can think of a few things that feel very very good but are very very wrong....

ummm...warm apple pie.

 

[noobi]

Oh well, if it feels good - it must be right. ..... no, hang on, I can think of a few things that feel very very good but are very very wrong....

Mrs Macs pies, very nice, but also very Australian. haha

 

[Jakobi]

Front race sag 50mm.The new springs were a little longer than stock.Had a ride last weekend & backed the compression off 3 clicks,even better.Now here is the messed up bit.Checked the rear before riding & got 50mm sag & 127mm race sag,huh!!I don't remember setting it up like this?Anyway,got a drift out & wound the hell out of the preload.As my riding buddy said "keep winding,your a fat bastard",didn't bother being too accurate on the measuring,rode all day & it felt way better.Steered & cornered sharper & more stable.Checked the measurements tonight & I have 12mm sag & 80mm race sag?Have I gone too far on the preload,but it felt real good?

You haven't told us what weight spring you're running in the rear. With .48 fork springs you'd expect 5.6/5.8 spring in the rear. If you're still running the stock 5.2 then its no surprise you had to preload it big time. It probably felt better because it would have been more balanced front to rear, but you have compromised the working ability of the rear end by cranking down on it so much. Go hit some chopped out trail, roots, ruts, logs and whoops and see if it still feels so good Even if it does there's room for improvement.

 

[gg3]

Stock 5.2 rear.Time for a spring change.

 

[Simmo737]

Stock 5.2 rear.Time for a spring change.

Mos def! you will see a huge increase in frontend grip and compliance, the rear will feel soooo much better as well. Aim for 30mm free sag and 108 race (plus or minus 5) and 1 to 2 mm of fork tube showing above the top triple (not including the cap) and the bike will turn and track like magic.

I reckon you'll need a 5.8 to achieve those sag numbers with around 10 mm of preload.

 

[gg3]

Thanks guys,will get it underway & post a report.It's a shame these bikes get test ridden & reviewed with the wrong spring rates as the transformation is unbelievable.

 

[Jakobi]

Its not just these bikes. Almost all bikes are set up for riders around 70kgs geared up and ready to race. Its a good middle of the field number.

The thing with suspension is that the best you've had is the best you'll ever know and its not until you start making changes that you'll begin to determine whats working well and whats not. I guess most things probably follow this theory too... mmm apple pie!