Race Tech Shock Spring Woes

[Guest hycide]

So I decided to upgrade the boingers on my bike, as I'm 250lbs and was tired of my bike doing the hula every time I leaned her over. The fork springs install went smoothly, and I replaced the nasty stock 10w oil with nice new 5w to compensate for dramatically stiffer spring rate.

The shock spring, however, did not go so well and I need to know what to do, or what I may have done wrong. The Eibach spring in 16.8kg I was sent by race-tech is over an inch shorter than the stocker. As a result, even with full still preload on the collar, it is not long enough to fit onto the stock shock. The part number is SESP 700225900, which corresponds to the correct rate on racetech's website. I bought all three adapters as well. WTF?!?

[Baileyrock]

So I decided to upgrade the boingers on my bike, as I'm 250lbs and was tired of my bike doing the hula every time I leaned her over. The fork springs install went smoothly, and I replaced the nasty stock 10w oil with nice new 5w to compensate for dramatically stiffer spring rate.

The shock spring, however, did not go so well and I need to know what to do, or what I may have done wrong. The Eibach spring in 16.8kg I was sent by race-tech is over an inch shorter than the stocker. As a result, even with full still preload on the collar, it is not long enough to fit onto the stock shock. The part number is SESP 700225900, which corresponds to the correct rate on racetech's website. I bought all three adapters as well. WTF?!?

First off that rear spring rate is NO Where Near anything close for your weight!!! :laugh:

At 250lbs you should be using no less that a 21kg and up to a 23-24kg rear spring!

Stock is 15.3kg and that's for a 150/160 lb rider. I'm 190 lbs and found a 19kg spring is about dead on for me. You weigh 50% more than what the bike was built for and they sent you a spring 10% stiffer than stock! :goofy:

What rate front springs did they send you, should have been at least 1.0kgs(stock .74kg)?

They may have sent you a ABS model spring which is shorter because of the remote preload collar(I'm pretty sure).

On fork oil, you may find the 5w not controlling the rebound side enough because of the stiffer springs. If your forks bounce back to quickly you'll need to go back to 10w or maybe blend some 7.5w.

Keep us informed on your progress and get the correct rear spring when they replace this one with the right length one! :cool:

PS screw Race Tech on the rear spring! They only list one rear spring stiffer than stock and that's the 16.8kg they sent you! That's a joke!!! :mad: Just send it back and call Sonic Springs or Ohlins USA to get the correct rate and length spring.

[Guest]

thanks for the info! I'll get in touch with ohlins today. Race Tech really disappointed me. It was over 2 months between order and delivery. Hopefully the fork springs don't suck!

[Baileyrock]

thanks for the info! I'll get in touch with ohlins today. Race Tech really disappointed me. It was over 2 months between order and delivery. Hopefully the fork springs don't suck!

Ohlins USA was great and i had my spring in less than a week, there in NC.

Many members have had good results with Sonic springs and their less expensive too! I think you can find a thread in the "bargains" section.

You can post up, but there are many 250 pounders here that have changed their spring and None have less than a 21 kg on the back. Well 1 strange with a f4i shock! :cool:

[WERA910]

Be aware that many oem springs are special lengths or diameters... so, sometimes when changing springs you have to get something shorter that is the right rate, and then have a spacer made or purchased to make up the difference. This is how I resprung my stock GSXR shock. Traxxion happened to have the right spacer, and it was only about $25.

http://traxxion.com/detail-61.aspx

When respringing a shock going onto a CB-1 years ago I had Lindeman Engineering make a custom spacer for it.

I'm really entralled with the product and service provided to me recently from Hyperco springs. I've been buying Hyperco's from Traxxion Dynamics for years, but found out recently I can go direct to the company, and they're located in Indiana!

http://www.hypercoils.com/Catalog.aspx

If you need my help, measure the inside diameter of the top and bottom of the stock spring, and the free length. I'll see if I can give you the correct combination to get your spring right.

[WERA910]

I did check and the 1200 lb (21.5kg/mm) spring is readily available in both 6 and 7" lengths (the most common) for the 2.25" ID spring (which is most likely what you have.... they're only $91 also.

[wera803]

I've never used them, but Lindemann Engineering seems to have a large selection of Eibach springs available too. You just choose the length and rate you want.

http://www.le-suspension.com/catalog/produ...aff89575a3174b4

[JamieDaugherty]

First off that rear spring rate is NO Where Near anything close for your weight!!! :cool:

At 250lbs you should be using no less that a 21kg and up to a 23-24kg rear spring!

Stock is 15.3kg and that's for a 150/160 lb rider. I'm 190 lbs and found a 19kg spring is about dead on for me. You weigh 50% more than what the bike was built for and they sent you a spring 10% stiffer than stock!

I calculate 16.88kg/mm for his weight and a street setup. Even a race setup is less than 18.0kg/mm. I add extra preload via a thicker spacer when I setup shocks and haven't had any trouble. I know that Traxxion uses uber heavy spring rates but it doesn't seem like anyone else does.

[Baileyrock]

First off that rear spring rate is NO Where Near anything close for your weight!!! :cool:

At 250lbs you should be using no less that a 21kg and up to a 23-24kg rear spring!

Stock is 15.3kg and that's for a 150/160 lb rider. I'm 190 lbs and found a 19kg spring is about dead on for me. You weigh 50% more than what the bike was built for and they sent you a spring 10% stiffer than stock!

I calculate 16.88kg/mm for his weight and a street setup. Even a race setup is less than 18.0kg/mm. I add extra preload via a thicker spacer when I setup shocks and haven't had any trouble. I know that Traxxion uses uber heavy spring rates but it doesn't seem like anyone else does.

I've NEVER heard of anyone coming up with numbers this low for the VFR JD and the Race Tech site has had a recent major change in there VFR spring rate calculation recently also!

Would be interested in knowing what method your using as this is one area I completely disagree with you. :laugh:

[jlrotax583]

Hey guys,

here is another source for springs. Decent prices and good service.

http://www.eshocks.com/hyp_make.asp?Manf=All

I ordered a 950Lb Hypercoil 7in for my 4th gen.

Props for Sonic Springs also. Good support and quick delivery.

Recieved it in 2-3days.

Ride on,

Jon

[turtlecreek]

as bailey mentioned, i'm the odd bird with f4i and 18kg from eibach.....love 'em! i am 250lb and the preload works fine (25-30mm rear). i have not, to the best of my knowledge, had any issue with the spring being too light on the street. however, calcs do say i should have a little more spring...19kg? not sure where all the 21kg plus is coming from. i ride medium fast on the street.

[Baileyrock]

as bailey mentioned, i'm the odd bird with f4i and 18kg from eibach.....love 'em! i am 250lb and the preload works fine (25-30mm rear). i have not, to the best of my knowledge, had any issue with the spring being too light on the street. however, calcs do say i should have a little more spring...19kg? not sure where all the 21kg plus is coming from. i ride medium fast on the street.

:blush: Yeah, you have a lighter spring rate(supposedly?) than my bike, but the rear of your bike feels ROCK hard compared to my stiffer sprung shock??? It feel like you have a 21 kg spring on it!

Btw what is the free sag on that rear?

With a 19 kg rear spring on the back and my weight of 190lbs I currently have 10-12mm of free sag and 32-34mm of rider sag.

[JamieDaugherty]

I've NEVER heard of anyone coming up with numbers this low for the VFR JD and the Race Tech site has had a recent major change in there VFR spring rate calculation recently also!

Would be interested in knowing what method your using as this is one area I completely disagree with you. :blush:

I've got a spreadsheet that I use which includes all of the calculations for wheel load, shock load, linkage ratio, etc. My numbers come out very consistent with RaceTech's online calculator (I just checked again and it's still the same). It looks like I need to go back through the data with a fine tooth comb and see if there are any discrepancies. Just on the surface, there is no way I can see having a 1300lb/in (23kg/mm) spring on there.

[Baileyrock]

I've NEVER heard of anyone coming up with numbers this low for the VFR JD and the Race Tech site has had a recent major change in there VFR spring rate calculation recently also!

Would be interested in knowing what method your using as this is one area I completely disagree with you. :blush:

I've got a spreadsheet that I use which includes all of the calculations for wheel load, shock load, linkage ratio, etc. My numbers come out very consistent with RaceTech's online calculator (I just checked again and it's still the same). It looks like I need to go back through the data with a fine tooth comb and see if there are any discrepancies. Just on the surface, there is no way I can see having a 1300lb/in (23kg/mm) spring on there.

Yeah, I don't know what happened to the RaceTech site info? There spring choice for the VFR tops out at the 16.8 kg, what was recommended for him. A few years ago it was race tech numbers I used to get my current rate spring. They seem to have changed the web site and spring suppliers recently.

Agreed, no 23kg spring, but 20-21kg should be close based on mine and a half a dozen other 250 plus members recommended spring rates.

btw did you do turtlecreeks F4i shock? His rear suspension is twice as stiff as my Ohlins w/19kg spring? :huh:

[turtlecreek]

as bailey mentioned, i'm the odd bird with f4i and 18kg from eibach.....love 'em! i am 250lb and the preload works fine (25-30mm rear). i have not, to the best of my knowledge, had any issue with the spring being too light on the street. however, calcs do say i should have a little more spring...19kg? not sure where all the 21kg plus is coming from. i ride medium fast on the street.

:blush: Yeah, you have a lighter spring rate(supposedly?) than my bike, but the rear of your bike feels ROCK hard compared to my stiffer sprung shock??? It feel like you have a 21 kg spring on it!

Btw what is the free sag on that rear?

With a 19 kg rear spring on the back and my weight of 190lbs I currently have 10-12mm of free sag and 32-34mm of rider sag.

i just went out and varified static sag.....15mm

[JamieDaugherty]

Yeah, I don't know what happened to the RaceTech site info? There spring choice for the VFR tops out at the 16.8 kg, what was recommended for him. A few years ago it was race tech numbers I used to get my current rate spring. They seem to have changed the web site and spring suppliers recently.

Agreed, no 23kg spring, but 20-21kg should be close based on mine and a half a dozen other 250 plus members recommended spring rates.

btw did you do turtlecreeks F4i shock? His rear suspension is twice as stiff as my Ohlins w/19kg spring? :goofy:

I don't think that I did his shock, so I can't really say. Don't forget that compression (and rebound too) damping will affect how it 'feels'.

One thing that caught my eye is the static sag numbers being mentioned. I normally like to see 5mm or less of static sag. When you get more than that it's an indication that your spring is too stiff. I know, this seems counter intuitive, but if you think about it you will understand. Think of it from the spring rate perspective: when you get off the motorcycle you are removing X number of pounds(kg). Since the spring rate is lb/in, the higher the rate the less the distance traveled for that same X pounds. If you start at 35mm of rider sag, a higher rate spring will not return as far, thus producing a higher static sag number. For high spring rates it's not uncommon to have 0mm of static sag. In fact, my spreadsheet calculates this and it sometimes comes up with a negative number for the static sag, meaning that the weight of the bike is less than required to start compressing the spring.

[turtlecreek]

Yeah, I don't know what happened to the RaceTech site info? There spring choice for the VFR tops out at the 16.8 kg, what was recommended for him. A few years ago it was race tech numbers I used to get my current rate spring. They seem to have changed the web site and spring suppliers recently.

Agreed, no 23kg spring, but 20-21kg should be close based on mine and a half a dozen other 250 plus members recommended spring rates.

btw did you do turtlecreeks F4i shock? His rear suspension is twice as stiff as my Ohlins w/19kg spring? :goofy:

I don't think that I did his shock, so I can't really say. Don't forget that compression (and rebound too) damping will affect how it 'feels'.

One thing that caught my eye is the static sag numbers being mentioned. I normally like to see 5mm or less of static sag. When you get more than that it's an indication that your spring is too stiff. I know, this seems counter intuitive, but if you think about it you will understand. Think of it from the spring rate perspective: when you get off the motorcycle you are removing X number of pounds(kg). Since the spring rate is lb/in, the higher the rate the less the distance traveled for that same X pounds. If you start at 35mm of rider sag, a higher rate spring will not return as far, thus producing a higher static sag number. For high spring rates it's not uncommon to have 0mm of static sag. In fact, my spreadsheet calculates this and it sometimes comes up with a negative number for the static sag, meaning that the weight of the bike is less than required to start compressing the spring.

you did not do my shock. shy in murfreesboro did. we may have a term issue here. i call static sag, the difference between the bike unloaded and lifted off the wheel (ie full extension) and setting the unloaded bike just on the back wheel and seeing what the difference is. my bike alone depressed the shock 15mm. if you had the preload jacked for rider sag, then you might see 5mm sag or perhaps NO sag, but this would indicate too LOW of a spring rate. THAT is counter intuitive.

[V4 Rosso]

Agreed, no 23kg spring, but 20-21kg should be close based on mine and a half a dozen other 250 plus members recommended spring rates.

I am 230lbs and the suspension tech that build the shock for my 3rd gen used a 21kg (210Nmm⁻1) spring. He also set preload and when I mounted the schock on the bike and measured sag, it was spot on. Not sure how the 3rd & 6th gen differ in geometry.

[Baileyrock]

Zero Free Sag is never desirable! One of the things this indicates is that the rear shock will top out constantly which will increase a chance of traction loss in certain situations.

On the Rear for track use I look for 2-5mm of Free sag and 5-10mm for street, desirable Dynamic/Rider Sag numbers would be 25-30mm track & 30-35 mm street on the rear. (most of this is from K Code's book PRT).

JD is correct in that too little free sag indicates to soft a spring when rider sag is set within the proper range as does to much free sag indicates to stiff a spring. :goofy:

TC your correct in how you get static/free sag, it's how much the bike moves with just it's own weight vs a topped out/unladen shock or fork. Your 15mm of static/free sag is too much per most all experts, this would indicate a too stiff spring. But we need to make sure we check rider sag with full gear on in order to get the real/correct numbers. Sounds like you need to crank in a few turns of rear preload, get geared up and check free & rider sag again to see where you really are spring wise. :beer:

I can help anytime!

[turtlecreek]

yep, just reread what he said and we said the same thing, just from different sides...sorry JD, misread what you wrote.

all this spring rate stuff seems to indicate i weight a svelt 180lbs....i think i'll keep the spring and throw away my bathroom scale! burger anyone? :goofy:

[turtlecreek]

http://www.onthethrottle.com/content/view/73/40/

[vfrcapn]

JD is correct in that too little free sag indicates to soft a spring when rider sag is set within the proper range as does to much free sag indicates to stiff a spring. :biggrin:

I'm not getting this, if free sag (shock fully extended - just weight of bike on shock) is too much, more than 10-20mm, the spring is too stiff? Or are you saying the preload is just not set correctly? Too little or no sag at all would mean the spring rate is too low and you need a stiffer spring?

Your 15mm of static/free sag is too much per most all experts, this would indicate a too stiff spring. But we need to make sure we check rider sag with full gear on in order to get the real/correct numbers. Sounds like you need to crank in a few turns of rear preload, get geared up and check free & rider sag again to see where you really are spring wise. :ph34r:

I can help anytime!

Ohlins recommends 10-20mm for what it's worth.

[Guest]

I'm 265# and I run a 1300# spring. I have 10 mm free sag and 30 mm dynamic sag. I determined my correct shock spring as outlined in Trevitt's book.

BTW, a Baxley sport chock makes checking sag 100 times easier. With the Baxley, checking rear sag is me on the bike and the wife reading the ruler. Checking front sag is done with a tie wrap. To get the bike level using a Baxley, set the lock pin on the Baxley in the forward most position. This raises the front of the bike 1". Take two pieces of 1/2" plywood, screw them together, and make a ramp for the rear wheel to rest on. This keeps your bike in the same attitude as without the Baxley.

[Baileyrock]

JD is correct in that too little free sag indicates to soft a spring when rider sag is set within the proper range as does to much free sag indicates to stiff a spring. :biggrin:

I'm not getting this, if free sag (shock fully extended - just weight of bike on shock) is too much, more than 10-20mm, the spring is too stiff? Or are you saying the preload is just not set correctly? Too little or no sag at all would mean the spring rate is too low and you need a stiffer spring?

It does sound goofy, but basically if you set rider SAG on your bike to achieve the proper/correct numbers like 30-35mm on the rear for street riding and then check Free sag (sag of bike only). If there is no free sag that indicates a Soft spring, because you had to crank in so much preload to achieve the rider sag numbers that there is no Free sag available(spring is so preloaded that it Tops out the shock and there's no remaining movement available). Don't know if that help any or not? :ph34r:

I'm also using Trevitt's book thanks to Pete! :ph34r:

I'm not sure why Trevitt suggest running less free sag than Ohlins if they are recommending 10-20mm, if that's the case than TC is dead nuts! :ph34r:

[vfrcapn]

It does sound goofy, but basically if you set rider SAG on your bike to achieve the proper/correct numbers like 30-35mm on the rear for street riding and then check Free sag (sag of bike only). If there is no free sag that indicates a Soft spring, because you had to crank in so much preload to achieve the rider sag numbers that there is no Free sag available(spring is so preloaded that it Tops out the shock and there's no remaining movement available). Don't know if that help any or not? :ph34r:

I'm also using Trevitt's book thanks to Pete! :biggrin:

I'm not sure why Trevitt suggest running less free sag than Ohlins if they are recommending 10-20mm, if that's the case than TC is dead nuts! :ph34r:

Makes sense, thought about it a little after my post and figured this is what you meant. btw, this is exactly what I had with the 17kg spring, preload just about maxed to get rider sag close but almost no free sag resulted. 19kg spring with preload somewhere around 1/3-1/2 and both sag settings are in the right range now.