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Clegg78

Upgrade Rear Spring DIY? (keep stock unit, but upgrade the spring)

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Hey there, I have a Tracer 900 GT and am overall happy with the suspension as it is setup (I spent a day tuning the rebound/compression/preload-sag)  and its not bad for my 250lb heft.   But I am going to be doing more touring with more gear in the boxes and I want to ensure that the rear of the bike isnt too overwhelmed.   I was looking to upgrade the rear spring based on the Racetech sizing about 15 -20% higher spring rate.   I figure from the setting range I am in on the shock for rebound I have enough range to keep it dampened even with the raised spring rate.    I know I can buy a whole new shock, but I am not there yet in terms of needing it... the bike rides very solid as it is, and dropping $500 - $1K on a shock with a higher spring rate seems excessive for the relatively minor change I am looking to make right now.  (I do like the remote preload availability and that seems to take aftermarket shocks instantly to the $700+ range.) 

I have sprint compressors, and have done car suspension work in the past, but I have zero idea about what it takes to do a rear shock spring change.    It also isn't documented in the service manual.    

Any one done a spring change on the rear unit?  I tried searching but the results seem to be squarely on the front suspension. 

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11 minutes ago, Clegg78 said:

Hey there, I have a Tracer 900 GT and am overall happy with the suspension as it is setup (I spent a day tuning the rebound/compression/preload-sag)  and its not bad for my 250lb heft.   But I am going to be doing more touring with more gear in the boxes and I want to ensure that the rear of the bike isnt too overwhelmed.   I was looking to upgrade the rear spring based on the Racetech sizing about 15 -20% higher spring rate.   I figure from the setting range I am in on the shock for rebound I have enough range to keep it dampened even with the raised spring rate.    I know I can buy a whole new shock, but I am not there yet in terms of needing it... the bike rides very solid as it is, and dropping $500 - $1K on a shock with a higher spring rate seems excessive for the relatively minor change I am looking to make right now.  (I do like the remote preload availability and that seems to take aftermarket shocks instantly to the $700+ range.) 

I have sprint compressors, and have done car suspension work in the past, but I have zero idea about what it takes to do a rear shock spring change.    It also isn't documented in the service manual.    

Any one done a spring change on the rear unit?  I tried searching but the results seem to be squarely on the front suspension. 

I also am familiar with the front spring swap out but have never done the rear. (Honestly, I have always bought an aftermarket shock)  With the spring compressor, you should be halfway there.  I would consult You Tube or call the shop and ask if they can swap the spring for you.


***2015 Candy Red FJ-09***

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Posted (edited)

Norwest Suspension used to respring and revalve these (FJ-09 OE), and I remember that this shock is not easily taken apart... and the spring isn't a standard size. You could call them and ask a couple questions to see if it's even worth looking into.

https://www.norwestsuspension.com/

EDIT: Noticed you have the GT. Still worth a shot to call them and ask.

Edited by piotrek
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canada.gif.22c5f8bdb95643b878d06c336f5fe29f.gif - IBA #66956 - 2015 Yamaha FJ-09

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2 hours ago, piotrek said:

Norwest Suspension used to respring and revalve these (FJ-09 OE), and I remember that this shock is not easily taken apart... and the spring isn't a standard size. You could call them and ask a couple questions to see if it's even worth looking into.

https://www.norwestsuspension.com/

EDIT: Noticed you have the GT. Still worth a shot to call them and ask.

Ohh wow, Terry @ Norwest did the suspension on my Triumph years ago!    Forgot they were still in business. 

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Hi Clegg, 

What spring rate have you decided to replace your rear with? If you have replaced them, how's the ride?  My concern is more on safety than anything else. Not looking to knee down the bike anytime soon.

I'm 216 lb but ride mostly with a pillion, getting the bike to it's load limit. My preloads are all at max, thus changing springs is the next step. 

Unfortunately, in my country, most places sells complete suspension sets (Ohlins, K-Tech etc) and harder to find just spring, which means I have to order. 

Also, Ohlins like the YA537 only comes with 115 N/mm spring, and I'm wondering if this is sufficient for total weight up to 395 lb (single rider is fine I guess). Losing weight is one solution, but at 6'2" there's a limit on how low I can go 😁.  Anyone can chime in on this? 

 

Thanks. 

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Posted (edited)

105n/m is about as far as you can go on the stock shock. With a 105 I set my rebound at  4 clicks out, 10,000+km later I'm at 2. I'll likely replace the shock before it hits 20,000km. 

To replace the spring - Compress the spring. The collar falls down, little piece inside the collar comes out. 

Hard to describe but easy to see once the spring is compressed. 

If you don't have the tools/your tools aren't suitable, take the shock and spring to a shop. It is a quick and easy job with the right tools so wont cost much. 

 

Replace fork springs too. You might think you don't need to now, you'll realise you should have pretty quickly. 

Edited by StealthAu
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10 hours ago, Keribang said:

Hi Clegg, 

What spring rate have you decided to replace your rear with? If you have replaced them, how's the ride?  My concern is more on safety than anything else. Not looking to knee down the bike anytime soon.

I'm 216 lb but ride mostly with a pillion, getting the bike to it's load limit. My preloads are all at max, thus changing springs is the next step. 

Unfortunately, in my country, most places sells complete suspension sets (Ohlins, K-Tech etc) and harder to find just spring, which means I have to order. 

Also, Ohlins like the YA537 only comes with 115 N/mm spring, and I'm wondering if this is sufficient for total weight up to 395 lb (single rider is fine I guess). Losing weight is one solution, but at 6'2" there's a limit on how low I can go 😁.  Anyone can chime in on this? 

 

Thanks. 

I went to the Racetech site to get an idea of recommended values.   They have a spring rate calculator for specific bikes: https://www.racetech.com/ProductSearch/12/Yamaha/Tracer 900/2019   Mine came to ~12.5 for the rate (vs 10.0 which is stock on the GT) 

But I emailed Norwest as cited above - I trust Terry there with my suspension as he really helped me in the past on other bikes.   And I am going to let him give me some guidance on what I should do.   I am going to do a long touring ride loaded up in a few weeks and going to see if I can get the stock suspension comfortable with the load on that trip and then tweak from there with Terry. 

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If you are buying an Ohlins shock from a reputable dealer you will need to fill out all the details of the type of riding you do and weight that the shock will be carrying so that the correct spring will be fitted 

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I highly recommend the folks at Traxxion Dynamics.  You could send them your shock and they can rebuild it with the proper spring and valving to match.  I had them do this on my Ninja 1000 with excellent results.  

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There is nothing like spending a day riding with friends in the grip of a shared obsession.

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Forget re-springing stock shock. Damping (what there is) would be way out. Really the best thing, if you can afford it and as mentioned before is a new unit from one of the decent/big brands. FYI for a big trip, two up loaded, a smidge over max load limit, I had an 850lb spring in my Nitron NTR2 (GT Tracer), which was amazing. I can't quite get enough sag for solo riding now, so I'm going down a bit, literally just sent suspension away. I'm guessing I'll end up in the high 700lbs. I am 176lb.

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11 hours ago, Manxkiwi said:

Forget re-springing stock shock. Damping (what there is) would be way out.

This.  Changing to a much stiffer spring without changing the valving to match can create other issues.  A new shock or a rebuild of the stock unit with new springs and valves is the way to go.  

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There is nothing like spending a day riding with friends in the grip of a shared obsession.

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So does the Ohlins rear shock (STX46) fit the 2019+ Tracer?    I see it listed up to the 2018 model of the MT-09/tracer but not for the 2019.  I know there was a swingarm change for the 2019, did it change the shock length?

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I don't know for sure about the shock length, though I would be surprised if it were different.

The new, longer swingarm variants will almost certainly require a stronger spring than the originals. More leverage.

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5 hours ago, Clegg78 said:

So does the Ohlins rear shock (STX46) fit the 2019+ Tracer?    I see it listed up to the 2018 model of the MT-09/tracer but not for the 2019.  I know there was a swingarm change for the 2019, did it change the shock length?

In the U.S., 2018 was the transition year and we got neither the older FJ or the newer Tracer.  Everywhere else got a 2018 model though, I think if its listed for a 2018 model then it is for the newer "Gen II" bike. 


***2015 Candy Red FJ-09***

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