[math2014]

Hi all,

Quick q.

When measuring the shaft of a shock, should we include in the measurement the bottom-out rubber bumper?

When a company says , stroke 2" , wheel travel 6" for example, do they include the rubber bumber in the 2" measurement? If yes, then the leverage ratio on the above example wont be 3-1 unless the rubber bumper has 0mm thickness.

Correct me if i am wrong... just trying to figure out the accurate leverage ratios on enduros and enduros SX.

BTW a year ago some peep here has an SX with a romic... who was he?

Thanks
Yannis

 

[zedro]

slide the rubber bumper up the shaft; the chromed part of the shaft is what you measure. That bumper will get squeezed down to pretty much nothing so dont worry about it.

 

[seismic]

Yeah...ignore the bumper !

 

[math2014]

Cheers mates,

That is all i needed to know .... off to calculations now

 

[Kntr]

Depends on the bumper. My Avalanche bumper is SUPER stiff. I dont think that thing would squish too well.

 

[math2014]

Well it is a fox vanilla shock so... the bumber seems pretty soft.

 

[seismic]

I think no matter which bumper, - when you are bottoming out your shock, the pressure with which you are compressing the pring will make ANY bumper look like a pan-cake !

 

[math2014]

ok, so according to the new bumper theory the enduro (02-04) has a 2.77-1 levevare, which means my bike will get 5.6" of travel ..dont ask how or why

thanks for the answers mengs

 

[punkassean]

Your bike is an SX right?

The regular Enduro uses a longer shock and gets more travel than the SX.

I'm not sure how you got your numbers but the leverage ratio is determined from the wheel travel and shock stroke. That number should be 4.5" max for the SX ("un-chipped") or 5.2" max for the regular Enduro (large-volume ITch). Are you running a longer than stock stroke shock or something???

 

[math2014]

Your bike is an SX right?

The regular Enduro uses a longer shock and gets more travel than the SX.

I'm not sure how you got your numbers but the leverage ratio is determined from the wheel travel and shock stroke. That number should be 4.5" max for the SX ("un-chipped") or 5.2" max for the regular Enduro (large-volume ITch). Are you running a longer than stock stroke shock or something???

Yes i ride an SX. The numbers are as you correctly said.

Now, i have realised that the stroke on the stock enduro is 1.875" giving 5.2" of travel , thus a leverage ratio of 2.77-1. BETD produces a new plate that makes the travel for the normal enduro 6" aka, 3.2-1 leverage ratio. So with a 3.2-1 leverage ratio and my 1.75" stroke shock i ll get 5.6" of travel. Correct me if i am wrong.

 

[punkassean]

I have always felt that I'd rather have less travel if it means having a lower leverage ratio. I think a really nice shock like a Ti-sprung Romic (because it will fit the SX) or remote res Ti sprung anything really. I'd also go for a Swinger 3-way over resorting to a higher than 3:1 leverage ratio. I just think the travel feels better (and therefore like more) with lower ratios due to the shock being able to dampen more efficiently.

So basically I'm saying that 4.5" with a 2.7:1 will feel so similar to 5.6" with 3.2:1 that it's not worth spending the $$$ and altering the geometry. I'd sell the SX (cool bike worth $$$) and get a more appropriate bike like the new SX trail if that's too expensive, get one of the many similar bikes out there.

If you could design a new link that allowed for a longer shock to get a lower leverage ratio, that would be cool.

 

[math2014]

I have always felt that I'd rather have less travel if it means having a lower leverage ratio. I think a really nice shock like a Ti-sprung Romic (because it will fit the SX) or remote res Ti sprung anything really. I'd also go for a Swinger 3-way over resorting to a higher than 3:1 leverage ratio. I just think the travel feels better (and therefore like more) with lower ratios due to the shock being able to dampen more efficiently.

So basically I'm saying that 4.5" with a 2.7:1 will feel so similar to 5.6" with 3.2:1 that it's not worth spending the $$$ and altering the geometry. I'd sell the SX (cool bike worth $$$) and get a more appropriate bike like the new SX trail if that's too expensive, get one of the many similar bikes out there.

If you could design a new link that allowed for a longer shock to get a lower leverage ratio, that would be cool.

According to BETD, my leverage ratio is 2.57-1 and with their link it will go to 3-1 giving me 5.25".

To be honest with you i got issues with front travel rather than rear travel hence i ll get a 6" Z1 with HSCV etc.... I would be very interested to know if any other shock other than the stock Vanilla R will fit my bike, as the romic you mentioned...

Another option IF i am to play with the rear of the bike... is to get a 7.5" i2i shock with 2" or 2.25" stroke, and flip the link to the slack setting

Getting a new bike is not an option as i am very happy with the SX ... i am just making thoughts on the rear shock etc... after seeing kidwoo altering his .

btw, the SX trail is 2200$ whereas my SX was 1100$, no way for me to spill another 1100$ for a "Fake 2005 need".

Thanks punk for the feedback....

Yannis

 

[punkassean]

If the kit only takes you to 3:1, I'd consider that acceptable. Plus if it matches a taller front fork (5-6") and you can set the link to the slack factory setting those things will balance it out. Sounds good! I'm sure a Romic will fit, there's no reason it won't. That or a Swinger 3-Way.

Post pics if you decide to do it.

 

[math2014]

If the kit only takes you to 3:1, I'd consider that acceptable. Plus if it matches a taller front fork (5-6") and you can set the link to the slack factory setting those things will balance it out. Sounds good! I'm sure a Romic will fit, there's no reason it won't. That or a Swinger 3-Way.

Post pics if you decide to do it.

The Kit has only 1 geometry setting unlike the stock linkage.

So the option is, either to get the kit and change leverage from 2.57-1 to 3.-1 or to get a longer shock and flip the factory link.

With respect to romic or swingers, unfortunately the SX uses a custom 6.75" i2i, and as far as i know the normal sizes for romics and swingers are 6.5" x 1.5" and 7.5" x 2" . Correct me if i am wrong.

The original idea is only to get a 6" fork to replace the 5" i am running.... only 2cm increase in a-c.

Yannis

 

[punkassean]

You might try contacting Romic to see if they can custom make you something. I keep thinking the SX uses a 6.5x1.5"

 

[math2014]

You might try contacting Romic to see if they can custom make you something. I keep thinking the SX uses a 6.5x1.5"

That is what MISTAKENLY specialized lists on their website.

Fox and actual real life measurements show that the shock is 6.75 x 1.75.

 

[Kornphlake]

Sorry to pee in your cherios but either you don't really like the geometry of the bike the way it is or you are in for a big suprise when the bb get's jacked up (only) 2cm and the front end get's raised ~2cm. It's going to be a different bike with similar angles but different geometry. You say you don't want to spend the money to buy a new bike but then you talk about getting a new fork, custom linkage plates and all the other upgrades which make me think you could at least break even selling the bike as is and buying something more suitable than the SX. Not criticizing you here but it almost seems like you bought the SX because you got a good deal on a rare frame and didn't really know what you were planning on doing with it, now that you're into riding you really need to get the right bike rather than putting money into bandaid fixes and mods to the bike you bought as a beginner.

 

[math2014]

To be honest with you Korn, i dont really like the fork on the frame... the fork was transfered from the ht i sold, and i could use a taller fork on the SX frame.

With respect to plates, shocks etc... they are just thoughts not needs. I got no issues with the frame, that is why i originally bought it, since it was the best possible frame i could get in Europe in the 5" territory.

The fork though, is a need since it has qr, ssvf and i could really use something better now that i have progressed.

changing the frame will cost me 1500$+ and nowhere close to breakeven unfortunately.

Changing the fork... thats 350$

(SX trail, 2200$, my frame 2nd hand... 700$ tops)

 

[Roasted]

Korn,

100% agree with you. I suggested to him when he first got it might not suit what he wants to do 100%...

However, He would need a new fork anyways and the plate is signifigantly cheaper than a frame. Might as well work with what he has. Then when he completely outgrows 5" he can get a big boy bike

 

[math2014]

Korn,

100% agree with you. I suggested to him when he first got it might not suit what he wants to do 100%...

However, He would need a new fork anyways and the plate is signifigantly cheaper than a frame. Might as well work with what he has. Then when he completely outgrows 5" he can get a big boy bike

plus add into the equation that AS-X, bullits , 5spots etc... were inaccessible here... (x2 the price)

Anyhow i am mostly interested into the fork not the plate ...

 

[mandown]

Since travel consists of a vertical and horizontal movement, how much of the horizontal movement is considered travel? To be absurd, you could create a geometry that moved so that the shock would compress and the wheel would have a more horizontal wheel path than a vertical wheel path. That would suck because horizontal travel does nothing to absorb bumps, but you would still have "travel."

I would think that the best measure of useful travel would be to plot the wheel path on a graph and focus on the vertial change from the start of compression to the end of compression. Obviously the horizontal movement needs to be considered in calculating the leverage.

Anybody know how the industry does it when they say a bike has "X-inches of travel" in their spec sheets?

Thanks,

 

[punkassean]

Travel should always be measured as vertical wheel travel, measured at the axle.

 

[zedro]

Since travel consists of a vertical and horizontal movement blah blah freakin blah....

this "leverage ratio" isnt as important as you guys think (for linkage based systems), since its only an average and doesnt actually tell you anything about the actual leverage at any given point in the travel.

so forget about horizontal this and whatever that, for simplicity just measure the vertical displacement of the rear axle. Its a relative measurement so no need to overcomplicate things which wont give you any useful info anyways.

 

[mandown]

Travel should always be measured as vertical wheel travel, measured at the axle.

SHOULD BE, but is it?

just as an example - the Ventana El Cuervo (http://go-ride.com/prod_cuervo.html) is said to have 9" of travel AND uses a 3" stroke shock. simple math would say that should be a 3:1 compression ratio. however, the wheel path is not perfectly vertical. depending on the amount of horizontal axle path travel, the ratio should be higher. right?

 

[zedro]

SHOULD BE, but is it?

just as an example - the Ventana El Cuervo (http://go-ride.com/prod_cuervo.html) is said to have 9" of travel AND uses a 3" stroke shock. simple math would say that should be a 3:1 compression ratio. however, the wheel path is not perfectly vertical. depending on the amount of horizontal axle path travel, the ratio should be higher. right?

it doesnt matter. Its linkage driven so the numbers, weither its via vertical displacement or chord length are meaningless. It just gives a loose reference to other bikes but is useless if you were tuning the shock or designing the linkage.

people who design the things arent looking at the chord length, but rather the vertical displacement for simplicity. Now weither its accurate or a rounded off number is another matter for the marketers.

 

[punkassean]

SHOULD BE, but is it?

just as an example - the Ventana El Cuervo (http://go-ride.com/prod_cuervo.html) is said to have 9" of travel AND uses a 3" stroke shock. simple math would say that should be a 3:1 compression ratio. however, the wheel path is not perfectly vertical. depending on the amount of horizontal axle path travel, the ratio should be higher. right?

Whether the path is perfectly vertical or not, you can still easily determine the actual vertical wheel travel. Draw a horizontal line at the center of the axle on full extension. Do the same at full compression. Now draw a perfectly vertical line connecting the two horizontal lines. That is the vertical wheel travel.

Make sense?

 

[mandown]

people who design the things arent looking at the chord length, but rather the vertical displacement for simplicity.

that is what i wanted to know. it was one of those little things in the back of my head that would chew at me at night. wondering if the marketing guys were factoring in anything other than the vertical displacement.

 

[math2014]

so according to the above i dont have the wrong bike