DH Cranks and Vivid Ti Spring Please HELP

[FatYZ0]

Hey guys.
I am looking at trying to make my bike lighter and i have two questions for you all.
1. I have a Rock Shox Vivid shock and i am looking for a Ti spring. does anyone know someone who makes them to fit?

2. I am in the line for new cranks as well as mine have seen a fair bit of action (and the look shit). What are a light set of cranks but strong enough to put up with a beating. I am not a light rider at 90kg, they are going on a '09 Norco Atomik, i am not a smooth rider but do look after my stuff. What do you guys think will be light but strong?

 

[eyes]

Yep ...

Hey FatY

Unless you are lucky enough to have one of the very very limited edition team only Rockshox Ti springs you will have luck here:

NukeProof - at your LBS or if you are too lazy to go down there - http://www.chainreactioncycles.com/Models.aspx?ModelID=28716

Big dollars hey??? But also helps your suspension work better...

Regards

Eyes

 

[Dene Dweller]

1. Pretty sure I read recently this is the only place for a vivid spring http://www.obtainiumperformanceproducts.com/, may be other places though.

2. Could get the old Saints, not cheap but bomb proof and light.

 

[udi]

1. Obtainium, or Nukeproof vivid-specific as already mentioned. Both very expensive these days thanks to the exchange rate unfortunately.

2. I'd suggest the new saints. They are lighter than most else on the market, only about 60g heavier than gravity lights, and are supposed to be comparable in strength and stiffness to the previous generation (which were a fair bit heavier).

Big dollars hey??? But also helps your suspension work better...

Not true.

 

[FatYZ0]

Thanks heaps guys. Please keep them coming and please No Old saints i have had the before and got rid of the cause of transport problems

 

[eyes]

Does so ...

Big dollars hey??? But also helps your suspension work better...

Not true.

Yes it does - I'm sure it could be quantified on a testing rig as well.

Tititanum alloys used in suspension springs have two advantages thanks to their material properties:

1. A significantly lower Elastic Modulus (EM). Where a typical steel spring would have EM = 80 GPa, a typical Ti spring would have EM = 40 GPa. Lower EM means the spring has a better response to vibration.

2. A significantly lower Density (D). Where a typical steel spring would have D = 8.0 g/mm3, a typical Ti spring would have EM = 5.0 g/mm3. Lower D means the spring has a lower inertia, allowing the spring to use more of it's recoil energy to keep the wheel in contact with the ground.

Eyes

 

[wormer]

As harsh as this may sound, but there are two ways to look at this. You could spend hundreds of dollars shaving a few grams (ok, a coupla hundred or whatever) off your bike or you can lose some of your own body weight by drinking a few less beers, eating better and riding more.

Before you pipe up, I did this, lost 7kg (183cm, was 83kg, now 76kg). Not a huge amount of weight lost but enough, feel better/fitter/stronger for it.

To lose that same amount of weight off my bike would probably not be possible and if it was would cost thousands.

Some may argue that a lighter bike feels more nimble etc when riding, but because my overall body strength has increased, flicking around my bike doesn't feel as hard as before.

Not trying to offend anyone (sorry if I did), you may 90kg and not a gram of fat on you. Just a different way off looking at the weight shaving issue.

 

[flamshmizer]

Don't forget to go to the toilet before a big race, save a few hundred grams there

 

[FatYZ0]

As harsh as this may sound, but there are two ways to look at this. You could spend hundreds of dollars shaving a few grams (ok, a coupla hundred or whatever) off your bike or you can lose some of your own body weight by drinking a few less beers, eating better and riding more.

Before you pipe up, I did this, lost 7kg (183cm, was 83kg, now 76kg). Not a huge amount of weight lost but enough, feel better/fitter/stronger for it.

To lose that same amount of weight off my bike would probably not be possible and if it was would cost thousands.

Some may argue that a lighter bike feels more nimble etc when riding, but because my overall body strength has increased, flicking around my bike doesn't feel as hard as before.

Not trying to offend anyone (sorry if I did), you may 90kg and not a gram of fat on you. Just a different way off looking at the weight shaving issue.

Dude i do not see why that would offend anyone as it is so true. i know i am not the skinniest of people but i am planning on doing that as well. The spring is only a drawing bored thing at this stage but in saying that the cranks are defiantly going to get changed as they look shit house.

 

[wormer]

Dude i do not see why that would offend anyone as it is so true. i know i am not the skinniest of people but i am planning on doing that as well. The spring is only a drawing bored thing at this stage but in saying that the cranks are defiantly going to get changed as they look shit house.

Cool, just covering my arse. Every chance people may take what I said as calling them fat bastards etc.
You could always remove your current cranks, sand them back and give them a respray whatever colour you want for a custom ghetto look.
In saying that, shiny new bits always look good! I have nothing bad to say about the Truvativ Holzfeller OCT (light, strong and don't get caught in trailers) or Race Face Diabolus (heavyish but tough as nails) on either of my bikes.

 

[eyes]

As harsh as this may sound, but there are two ways to look at this. You could spend hundreds of dollars shaving a few grams (ok, a coupla hundred or whatever) off your bike or you can lose some of your own body weight ...

Heard it before - but the guy hasn't asked what he should do to lose weight from his bike - he asked specifically what Ti springs fit his shock...

Plus - see what I was saying about shock performance - the Ti spring isn't just about shaving grams...

 

[toodles]

Stuff

Losing body weight isn't an option for a lot of people (not me - I could lose heaps). Plus new shiny stuff makes you feel better than celery.

Bring on the Ti goodies I say.

 

[jrewing]

Heard it before - but the guy hasn't asked what he should do to lose weight from his bike - he asked specifically what Ti springs fit his shock...

Plus - see what I was saying about shock performance - the Ti spring isn't just about shaving grams...

If you're getting that serious on the spring you might wanna test the true spring weight. you would probably be suprised on the variations between one 350lb spring and another 350lb spring from the same manufacturer.

Pesonally i'd prefer a steel spring and a proper valved shock than a stocker and a ti spring. Remember we're going down hill on really rough terrain. Seriously, how much time will a ti spring save on a 4 min track over a rear-end thats tracking nicely
It makes me wonder about peoples priorities on suspension sometimes.

Oops, i forgot i compete against other people. The ti spring will be heaps better everyone

 

[eyes]

hmm ...

I...you would probably be suprised on the variations between one 350lb spring and another 350lb spring from the same manufacturer....

Between manufactures you would see a difference - but for the same manufacturer - I doubt it (there may be a small variance between batches).

...Oops, i forgot i compete against other people. The ti spring will be heaps better everyone

What are you trying to say here?

 

[jrewing]

Between manufactures you would see a difference - but for the same manufacturer - I doubt it (there may be a small variance between batches).





What are you trying to say here?

Why do i give advice that possibly could make other people faster...its shooting myself in the foot.

I dont know about the same batch codes but in the same manufacturer and spring designation( although in motorcycles), i've seen and seen tested some big tolerances, like bigger than 25lb. On our bikes we always measure the springs.

 

[udi]

Yes it does

You said "it helps your suspension work better".

If a spring has "more recoil energy" then the damper is just going to have to provide more rebound damping, because it's not like we're currently suffering from springs that don't rebound quickly enough. As for the lower EM I'd like to see you quantify that with data that justifies saying "it helps your suspension work better".

I think if you slap on a Ti spring and tell yourself that your bike works better, you're being delusional. The only tangible benefit is the weight saving, and the only other remotely tangible factor you could discuss is the reduction in unsprung weight (given that the spring is the middle point between sprung / unsprung weight). Dave Weagle has suggested that the difference in that respect would be the same as removing the 18T cog from your cassette (i.e. fairly minimal).

 

[wormer]

Heard it before - but the guy hasn't asked what he should do to lose weight from his bike - he asked specifically what Ti springs fit his shock...

Plus - see what I was saying about shock performance - the Ti spring isn't just about shaving grams...

Hey guys.
I am looking at trying to make my bike lighter and i have two questions for you all.

I'm not here to argue. FATYZO asks about losing weight from his bike, with his 2 options being a Ti spring and new cranks. The way I read it was he wanted to shave a grams off his bike and was curious to see if anyone made a compatible Ti spring for his vivid. I am not saying I "invented the wheel" by saying to lose weight. Just another option, that's it, that's all.
FATYZO wasn't specific about increased performance with a Ti spring and but I did find your post (eyes) about the properties of Ti vs steel springs very interesting.

 

[udi]

If you're getting that serious on the spring you might wanna test the true spring weight. you would probably be suprised on the variations between one 350lb spring and another 350lb spring from the same manufacturer.

Between manufactures you would see a difference - but for the same manufacturer - I doubt it (there may be a small variance between batches).

Jrewing is correct, there are large variations in claimed vs. actual spring rates, I've read test data on fox "350lb" springs that have measured in very close to 300lb. In fact this variation in claimed vs. actual issue is probably the reason anyone genuinely notices a difference between steel and ti springs (if they do), because they assume they bought the same rate - but there could be a reasonable percentage of variation.

 

[No Skid Marks]

Mentioning having a shit, or loosing weight is obvious and virtually irrelevant. So once you've lost the weight, and had a shit, then possibly you may be interested in the benefits of a Ti spring.
Cylium(sp?) husk will help you shit.
A ti spring will knock a fair bit of weight out of your bike, and is a fairly non perishable item, that will only significantly loose it's value(compared to other bike products)if your current shock size becomes obsolete.
What is the ID of a Vivid spring?

 

[S.]

Yes it does - I'm sure it could be quantified on a testing rig as well.

Tititanum alloys used in suspension springs have two advantages thanks to their material properties:

1. A significantly lower Elastic Modulus (EM). Where a typical steel spring would have EM = 80 GPa, a typical Ti spring would have EM = 40 GPa. Lower EM means the spring has a better response to vibration.

2. A significantly lower Density (D). Where a typical steel spring would have D = 8.0 g/mm3, a typical Ti spring would have EM = 5.0 g/mm3. Lower D means the spring has a lower inertia, allowing the spring to use more of it's recoil energy to keep the wheel in contact with the ground.

Eyes

Sorry, but that's just wrong. Lower elastic modulus means you need to use thicker coils and/or less coils in order to get the same specific stiffness, ie spring rate. There is NO ADVANTAGE in terms of vibration response... unless you're talking about vibrations at over 1000Hz, which I can guarantee you wouldn't even show up in a PSD graph of your suspension's movements.

The inertia of a spring is hardly a huge factor in determining how well your suspension rebounds, especially if you're not setting tyre pressures accurate to within 0.1psi... or if you run any rebound damping at all.

Between manufactures you would see a difference - but for the same manufacturer - I doubt it (there may be a small variance between batches).

I have personally measured a few springs, including my own Fox spring which was rated at 450lbs/in - actual rate was 475lbs/in. I spoke to Fox themselves about whether this was normal and they said it was "within standard tolerances".