rear shock spring advice

[Terez]

New 21 T7 in the garage

 

I am going to resrping the rear shock but no other suspension mods....yet

 

After much research I feel I am right between a .85 and .90 spring.......90kg naked...ride solo with minimal luggage...no hard off road but aggressive dirt road riding.

 

Id like to have as lil preload as poss to achieve ideal sag....don't want to be too stiff tho.

 

85 or 90??

 

Feedback from those who have repsprung???

[DT675]

According to my calculator the 90 is the right one. But just barley.  So with that said, do you prefer a stiffer ride or softer one? Get the spring according to that answer. 
 

Also keep in mind the stiffer spring you go with over stock the more rebound needs to be added to control it. I can’t help but to wonder what spring rate becomes too much for the stock valving to control?

 

Anyway, I’m 81.65 kg and have the 85 and am super happy with it. I use almost no preload when I ride light, and dial in about 10 clicks of preload or more when loaded. 

Edited February 3, 2022 by DT675

[Ktmmitch]

Select the appropriate spring, from the drop-down menu above, based on rider, passenger & luggage loads below:

 

Rider(up to 75kg, inc clothing) with max 50kg luggage.................................................80N/mm

Rider(up to 85kg, inc clothing) with max 50kg luggage.................................................85N/mm

Rider(up to 95kg, inc clothing) with light passenger and/or 15kg luggage..................90N/mm

Rider(up to 105kg, inc clothing) with passenger and/or 30kg luggage.........................95N/mm

 

NOTE: If fitting lowering links, add 10% to rider weights for 20mm link, and 15% for 40mm links, to compensate for changes in rising-rate geometry.

 

[williestreet]

I am just a bit more than you at 97kg.

 90N Ktech spring and I need to put an extra 1.5-2mm preload to get 60mm sag.

 

I think the 90 would be best.

I will be adding a 2mm shim to my spring before riding season so I can run with zero preload added by the hydraulic adjuster.  

 

 

[Terez]

Thanks for the feedback so far Fellas

 

I have researched the various spring vendors charts...and digested a lot of info

I am definitely right on the middle of the two specs  85 vs 90

 

Im not so worried about the spring rate being too stiff so much as the 90 ending up not offering enuf sag with zero preload

 

This is why Im looking for actual results from those similar in weight/riding approach as myself using the 85 or 90 spring

[Poacher]

I am 88kg stark naked, not sure with all my gear on... maybe 110kg. I have a 90Nm KTech and run with 1 click of preload to get the sag correct. I purposely went for the heavier spring because I sometimes take a pillion, sometimes luggage and sometimes ride hard. Its perfect for me (dont forget the spring does sag over time).

[Terez]

I had read somewhere that the Ktech springs had a different rating number than others like Rally Raid and Racetech....something to the effect of the Ktech spring spec being a lower number than others??  

[williestreet]

2 hours ago, Terez said:

I had read somewhere that the Ktech springs had a different rating number than others like Rally Raid and Racetech....something to the effect of the Ktech spring spec being a lower number than others??  

The normal is N/mm but some still rate their springs in kg/mm.

90N= 9.18kg/mm

 

Most times you see it on fork springs where someone says they use a 9.3N fork spring.  People compare it to a 0.93kg/mm, when in reality a 9.3N= 0.948kg/mm or on a shock someone is trying to compare a 90N spring to a 9.0Kg spring.  When actually a 90N= 9.18KG/mm

 

Ktech specs in N/mm, Rally raid also in N/mm as John stated above, Racetech uses Kg/mm, so just be sure which unit you are looking at.

 

The thing to be aware of is the spring free length.

Ktech shock springs are quoted at 245mm long, which is 5mm  longer than the stated stock length of 240mm.(my stock spring measured 241mm)

Check the rally raid site but I believe their shocks are quoted as 235mm long, but he supplies a spacer you put on the bottom of the spring to take it back to 240mm stock length.

And remember you have to consider manufacturer tolerances.  1-3mm longer/shorter is probably a normal variance 

you might see as well.

 

I went with K tech because of availability here in Canada.  I had to factor the extra 4mm installed preload before I decided on a spring.  I know a 95N rally raid spring would have suited me better, but it was out of stock at the time and I didn't want to be surprised by customs brokerage fees when being stuff from over seas.

 

Do your math first.  A 90N ktech vs 90N Rally raid will give much different results because of the installed preload.  

 

This is why I would have preferred a simple threaded adjuster on the shock.  Finding a spring length compatable when you want perfect sag with no extra on the hydraulic adjuster is tough on some bikes.

 

Check out the suspension thread on ADV rider for lots of info.

Tenere 700 suspension info | Adventure Rider

---

Here is a bit of info for you T7 owners. I will build on it as i do more. Spring rates. I have calculated these. They are very close to what a tuner...

 

 

Edited February 3, 2022 by williestreet

[williestreet]

Stadium suspension in Montreal also sells springs that will fit.

 

[Terez]

Thanks Williestreet...that clears it up.

 

Good explanation of the newton vs kg/mm spring spec.

I am aware of the issue of different springs having different OAL and inner/outer diameters as well

 

I have used RT springs for some of my other bikes previuosly and usually ran into having to fab up spacers and other crap.

Def looking for a spring that will be the same or very similar spec to my oem to avoid shims/spacers and proprietary retainers etc from stock hardware.

 

Stadium sells springs for the T7 then?  What brand of spring do you know and are they similar in spec as far as free length/diameter etc?

Where did you get your Ktechs in Canada?  Vancouver?

 

 

[Poacher]

Rising rate springs throw a whole new spanner into the works too if you go down that route... dont do it

[williestreet]

47 minutes ago, Terez said:

Thanks Williestreet...that clears it up.

 

Good explanation of the newton vs kg/mm spring spec.

I am aware of the issue of different springs having different OAL and inner/outer diameters as well

 

I have used RT springs for some of my other bikes previuosly and usually ran into having to fab up spacers and other crap.

Def looking for a spring that will be the same or very similar spec to my oem to avoid shims/spacers and proprietary retainers etc from stock hardware.

 

Stadium sells springs for the T7 then?  What brand of spring do you know and are they similar in spec as far as free length/diameter etc?

Where did you get your Ktechs in Canada?  Vancouver?

 

 

Same spec, 55 ID x 240 long

 

My understanding is they are made in Quebec for them.   I believe they are located close to the Aerospace industry area and there is a manufacturer in that area that makes springs, but I can't confirm that.  It's possible they resell a Eibach or Hyperco spring, but I am not sure??

 

They are 240mm long so they would not be a Ktech spring.

 

When I spoke with them  the spring they sell is 55mm ID, 240mm long, and a choice of 9.2/9.4 or 9.6kg/mm.

They also had fork springs. 38mmOD x 425 x 6.6kg were the ones I was looking at. They probably had other rates, but they didn't have stock and couldn't give me a good estimate on availability so I went with Ktech stuff.

 

Theiry Lacombe was the guy I was speaking with.

If you go to their website and look at the Spring application chart you can figure out the part number you are looking for.  

Our bike is not listed, but 5524092 would be a 9.2kg/mm spring,  

 

Bayside performance in Vancouver sells Ktech products.  Our bike is not listed but they can get anything ktech sells. I sent them an email with the part number I wanted and they got back to me quickly with a total price everything included to my door.  Look up the parts on the Ktech usa site and send them the proper part number.  

Very good to deal with, no issues.

 

Rally Raid has great stuff and is a supporter of this board so give them consideration as well.  Unfortunately They were out of stock  when I was looking last spring.  

 

 

 

Edited February 3, 2022 by williestreet

[Terez]

32 minutes ago, Poacher said:

Rising rate springs throw a whole new spanner into the works too if you go down that route... dont do it

No worries there...would never entertain progressive springs...in anything.

 

Ive got a fairly good grasp of suspension setup and approaches...been riding/racing since the 80s..off road/street/sleds/atvs etc.

[Terez]

I was going to just order from RR in the UK...but got sidetracked ponderin between the 85 or 90 rate...then also learned the spring would likely be ~$200 cdn by the time it landed at my door

Once I get the spring rate settled Ill pull the trigger

 

Im a fan of supporting CDN business so will try Ktech parts thru Bayside first.

 

Thanks for the feedback..especially your detailed info Williestreet....preciate yer time

[AZJW]

@Terez I'm 198.8 lbs. /90kg, ready to ride and I went with a RR 90nm spring.  It takes just a couple of clicks to set the sag and tons of adjustment left for luggage or two up. 

 

Looks like Rockymountainatvmc.com has them in stock.

Rally Raid Products Shock Spring | Parts & Accessories | Rocky Mountain ATV/MC

---

The OEM shock spring fitted to the shock is only 70N/mm spring rate, so for most riders over 65-70kgs(143-154lbs), with no allowance for extra luggage or passenger, it will not give the correct sag settings...

 

[Terez]

Well both Rocky Mtn in the US and Rally Raid in the UK had stock...decided to order from Rocky MTN 

 

$150 in UPS pocket was a hard pill to swallow as well as international/overseas shipping these days has a lot of potential fail points

 

Going with the 90N spring .....very much appreciate all the feedback fellas     Ill post feedback here when I get riding in the spring...Snowmobiling now

 

Ive been riding bigbore adv bikes the last 6 yrs and am very tired of the weight, overkill power and the excessive tech/complexity

 

Very much looking forward to the T7..I had a chance to ride a friends bike last year both stock and when uncorked/tuned and sorted....immediately felt in synch with the ergos and chassis design....drastically less weight..and man was the motor ever a surprise....it truly punches way above its weight for power...but more importantly the character and delivery are so good.

So very impressed that Yamaha saw thru the trees and delivered what I and Im sure many wanted.....a competent reliable reasonable service interval machine with exc ergos, competent suspension and only the nec tech required for current epa regs and good performance but nothing over the top.

 

Its a great machine as is for many...still a lil heavy and many corners cut with components....BUT its priced fairly so those that are happy as is have an affordable machine to own/maintain and those that want to upgrade have a $$ envelope to do so 

 

 

[Bartek]

Slightly too late, as you already purchased springs, but i'm 88kg's without the kit and 99kg in riding kit, and i wouldn't want harder than 85Nm on the back...  needs 4-5 clicks for correct sag, still feels harsh. Also got 6.6Nm on the front and this feels too hard.

I think calculator on one of the Australian websites tells you 85Nm and 6.3Nm for 104 kg kitted (me in riding kit plus crashbars on the bike) and this one would suit my observations... all others suggesting 90Nm and 6.6Nm are to hard for me.

[SKunn]

If i remember correctly from advrider  suspension topic,  there was mentioned you can mix front springs. Swap one back to original. Ofc verify this info first.

[Goshary]

On 2/3/2022 at 8:15 AM, DT675 said:

 

 

Anyway, I’m 81.65 kg and have the 85 and am super happy with it. I use almost no preload when I ride light, and dial in about 10 clicks of preload or more when loaded. 

 am 78 kg and followed the advice  from K-TECH - bought their 85 nm spring (

Uprated shock spring Yamaha Tenere 700, white, 85 N/mm

Item #: SF-TTS-T700-85 )

With no gear no preload my  riding sag is 3 cm. When I've grabbed 16 kg kettlebell and jumped on T7, sag have increased to 4 cm or so, still way too short.

Just wondering if a) I'd have better bought 80 NM spring 2) will K-TECH spring get softer after few thousands km as it was happening with all my OEM Triumph' springs?

Any ideas?

Thanks

Edited February 9, 2022 by Goshary

[bth2]

yes it will settle .give it a couple hundred miles then recheck. mine seemed to settle quite a lot.

[williestreet]

5 hours ago, Goshary said:

 am 78 kg and followed the advice  from K-TECH - bought their 85 nm spring (

Uprated shock spring Yamaha Tenere 700, white, 85 N/mm

Item #: SF-TTS-T700-85 )

With no gear no preload my  riding sag is 3 cm. When I've grabbed 16 kg kettlebell and jumped on T7, sag have increased to 4 cm or so, still way too short.

Just wondering if a) I'd have better bought 80 NM spring 2) will K-TECH spring get softer after few thousands km as it was happening with all my OEM Triumph' springs?

Any ideas?

Thanks

Are you sure you are measuring it correctly?  What is the free sag?

 

It doesn't make sense that you only have 40mm rider sag with a total weight of 94kg.

Rider sag is difference between fully topped out,(bike on centre stand, wheel clear of the ground) and when you are sitting on it. 

For example my free sag (bike only)  is 17mm with a 90N spring and 3 clicks on the adjuster.  With no additional preload I would expect free sag to be approx 19mm.  

With a 85N it would probably be around 20-21mm free sag.  Hard to believe it only sags another 10mm when you sit on it.

I am guessing maybe you didn't top out the bike before getting your starting point?  A friend of mine is approx your weight and he gets 55mm sag with a 90N spring.  With a 85N I would almost expect approx 55mm sag with 0 additional preload on the adjuster.

 

 

 

Edited February 9, 2022 by williestreet

[Goshary]

26 minutes ago, williestreet said:

 

 

I am guessing maybe you didn't top out the bike before getting your starting point?  

 

 

 

exactly, this is the procedure I read in the internet (was quite amazed that the process is not as i got used to). My user manual is in Japaneese - useless paper.

Thank a lot, will re-measure today!

[williestreet]

I always shoot for 30% of wheel travel, (60mm) but running slightly less would not bother me.  

[Ktmmitch]

7 hours ago, Goshary said:

 am 78 kg and followed the advice  from K-TECH - bought their 85 nm spring (

Uprated shock spring Yamaha Tenere 700, white, 85 N/mm

Item #: SF-TTS-T700-85 )

With no gear no preload my  riding sag is 3 cm. When I've grabbed 16 kg kettlebell and jumped on T7, sag have increased to 4 cm or so, still way too short.

Just wondering if a) I'd have better bought 80 NM spring 2) will K-TECH spring get softer after few thousands km as it was happening with all my OEM Triumph' springs?

Any ideas?

Thanks

 I have found the K-Tech shock springs to be slightly longer than OEM, which gives less sag, especially Static (no Rider) for other springs, like-for-like spring weights

[Goshary]

3 hours ago, williestreet said:

I always shoot for 30% of wheel travel, (60mm) but running slightly less would not bother me.  

okay, re-measured sags: 60mm with no preload (difference between height with hanging rear wheel and height with me sitting with 16kg ketlebell).

85 NM spring seems to be right choice

 

thank you