New Springs Spring

[W0QNX]

3 general comments.

One fork could be longer than another if a person didn't thread the damper rod into the cap all the way before tightening the jam nut.

I like a smooth soft riding bike like my stock ST. I put fancy heavy springs in a bike once and HATED the harsh firm ride.

I measured the spring length of my MANY mile bike at the fork seal replacement last year. They were well within the book tolerance for stock length. I did add 1/2" of spacers (washers) just to raise the front a bit.

 

[etalors]

While we are on the topic. Does anyone know what the spring rate is for the oem spring. Thanks.

 

[dduelin]

While we are on the topic. Does anyone know what the spring rate is for the oem spring. Thanks.

.86 kg/mm

 

[etalors]

Thanks for the info. Any idea what rider weight the 0.86 kg/mm would be suitable for. I weigh between 190-200, depending on the time of the year. While I am not an aggressive rider and have no problems with the oem spring, including even the dipping while braking hard. I was thinking of going to a firmer spring from Sonic (listed below), in the hopes of improving the ride comfort. This is based on what I have read on the forum and also a ST riding friend. Any input from the guys.

ST1300 Sonic Spring

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Product Name+

Price​

Buy Now​

​	ST1300 - 1.00kg/mm Sonic Springs	$120.00​	Buy Now​
​	ST1300 - 1.10kg/mm Sonic Springs	$120.00​	Buy Now​
​	ST1300 - 1.20kg/mm Sonic Springs	$120.00​	Buy Now​

 

[Obo]

My Raceteck springs arrived last night... Honda fork seals and parts should be today, so I'm starting this project very soon. (Still trying to figure out the best fork oil weight too....)

My question is, I'm guessing you had to install everything to check the sag measurement, then remove the forks and caps again to either add shims or remove spacer length?

There's a lot of stuff in the forum sections to read though and some of it seems conflicting and confusing

 

[Bmacleod]

My Raceteck springs arrived last night... Honda fork seals and parts should be today, so I'm starting this project very soon. (Still trying to figure out the best fork oil weight too....)

My question is, I'm guessing you had to install everything to check the sag measurement, then remove the forks and caps again to either add shims or remove spacer length?

There's a lot of stuff in the forum sections to read though and some of it seems conflicting and confusing

If you go to this page https://racetech.com/page/title/IP FK SPR PRELOAD DAMPING ROD and follow their instructions for 25mm of preload, it will get you close, assuming the springs are set for your weight. If you are lucky, like I was, you will get your sag right the first time.

 

[Willsmotorcycle]

My Raceteck springs arrived last night... Honda fork seals and parts should be today, so I'm starting this project very soon. (Still trying to figure out the best fork oil weight too....)

My question is, I'm guessing you had to install everything to check the sag measurement, then remove the forks and caps again to either add shims or remove spacer length?

There's a lot of stuff in the forum sections to read though and some of it seems conflicting and confusing

My 2¢, it was my first upgrade so I did nothing clever. I did consult @dduelin however.

It turned out with the 95kg springs the OEM spacers fit with no modification except as noted above (washers). I have a Motion Pro fork oil "stick" so getting the volume right was easy. I did nothing with sag besides put them flush to the top bridge. I also put 5W (IIRC) oil in so the ride was as close to stock but the spring rate was obviously better. I didn't want it to be harsh, just tighter. I am not saying this is right or correct, just how I did it. When I put the rear in I will revisit everything including sag numbers. After watching Dave Moss (sp?) setting up race bikes I was inspired.

Hope it helps.

*Edit, checked my notes, yes I put in 5W.

 

[dduelin]

For comparison the brand of 5w makes a difference @Willsmotorcycle. Did you use a Showa product?

 

[Willsmotorcycle]

For comparison the brand of 5w makes a difference @Willsmotorcycle. Did you use a Showa product?

I used "Honda".

 

[Obo]

On the back of that it says "specifically engineered for the latest in suspension technology from Showa and KYB"



I bought the same brand / weight today from the dealer.

@Willsmotorcycle FYI I went with a heavier spring, the 1.00kg for riding two up & the trailer.

@Bmacleod Already had that PDF and those "settings" but will have to wait and see how it measures when it's assembled. The new Racetech spring is about 7/8" - 23mm longer than the one I took out. The old one was still above the minimum specs.



I've got some other possible issues now, but I'll move those to their own thread.

 

[dduelin]

Thanks for that @Willsmotorcycle. As I have mentioned before in other threads, the linked website and it's fork oil viscosity chart could be helpful in choosing a fork oil when looking for specific qualities one might be looking for after a rebuild or upgrade to the ST1300's cartridge-type forks. Honda HP 5W is listed and for example any listed product clustered slightly above and below Honda HP 5W is going to give similar damping qualities in the forks. For example compare Kayaba G5 with Honda HP 5w and Bel Ray 5w. The factory fill is Showa Suspension Fluid SS-8. FWIW, in my ST1300 I liked a blend of Showa SS-7 & SS-8 oils that have me a "weight" of approximately 6.7w.

Suspension Fluid - Pvdwiki

www.peterverdone.com

 

[Obo]

Racetech specfies 5wt oil to offset the stiffer springs so the rebound isn't as harsh.

 

[dduelin]

Racetech specfies 5wt oil to offset the stiffer springs so the rebound isn't as harsh.

You can see there can be quite a variation in actual damping values among nominally 5w products. Look at the Sikoline Fork Oil 5w or Spectro 5w compared to Showa Suspension Fluid SS-05 or Maxima 5w. That's all I am trying to highlight.