New Sonic Springs for front forks, spacers are not pre-cut

[Wintersdark]

Ok, so while I'm not totally useless, I've never taken apart a modern adjustable fork before.  I've watched the Dave Moss videos on the topic that have gone around the forum, and they're helpful, but don't really touch on the problem here.

I've got my new fork springs, but it turns out they're not really drop in replacements.  They aren't shaped to use the stock spacers and (according to the instructions) are not necessarily the same length as the stock springs.  The instructions explain how to measure to get the right size to ensure the preload range is correct, but I'm not really sure the best means to cut the spacer pipe - it's a big, gray, still chunk of some flavour of plastic pipe.  Obviously, the ends would need to be square and smooth cut.  

I've got a spring compressor, which as one knows screws into holes in the existing spacers, but this piece of pipe has no holes.  Should I drill holes in it?  Or will I not need to?  How real is the risk of weakening it to the point of failure?  Is it silly that I'm worrying about that?  I don't know what the stock spacers are made of. 

Ugh.  I was really hoping for a straight replacement, and am somewhat annoyed that it's not, but to return the springs will cost me nearly as much as the springs themselves ($50 shipping to get them, $50 shipping back, $80 springs) did so it's not really worthwhile. 

Anyone have some advice here about the best way to proceed?  There's no dedicated suspension shops nearby, and I'm concerned that random bike shops may not be equipped to deal with the spacers?  I have no idea, to be honest.

[peteinpa]

Did you check both ends of the springs? One end fits on the spacer.

I did this on my 2015. The Sonic springs were a direct drop in.  Exact same length.

 

 

[Wintersdark]

1 hour ago, peteinpa said:

Did you check both ends of the springs? One end fits on the spacer.

I did this on my 2015. The Sonic springs were a direct drop in.  Exact same length.

Yes.  Both ends of the springs are identical, and the kit came with a single length of spacer to cut and put in.

[Basket]

Do you have a 2019 or 2020 gt? I'm about to do my 2020 gt with race tech springs and also have questions and concerns with regard to spacers. Did you measure your stock springs and are they actually 305 mm? The springs I got from race tech are only 270mm so I have to increase the spacer length. Was thinking to use the stock spacer and add an additional spacer above or below the springs to achieve proper preload, but not sure what is the best way to go.

[Wintersdark]

Oh, crap.  I ordered the MT09 springs.  They should be the same though?  The OEM part numbers for the MT09 spacer is the same OEM part number as the Tracer 900 GT Spacer.  The springs are slightly different though, part number: 2PP-23141-00 for the tracer and 1RC-23141-00 for the MT09. 

These may be the same length; I don't know and won't unless I tear down the forks.  Hmmm.

 

[Wintersdark]

5 minutes ago, Basket said:

Do you have a 2019 or 2020 gt? I'm about to do my 2020 gt with race tech springs and also have questions and concerns with regard to spacers. Did you measure your stock springs and are they actually 305 mm? The springs I got from race tech are only 270mm so I have to increase the spacer length. Was thinking to use the stock spacer and add an additional spacer above or below the springs to achieve proper preload, but not sure what is the best way to go.

I have a 2019 GT, but the 2019 and 2020 are identical.

The instructions that came with the springs specifically said they were not the same length as stock, but I haven't measured the stock springs - I'm reluctant to start tearing into the forks as it stands, as I'm not really confident with what I'm doing in the first place and there's all kinds of questions.

However, apparently the stock springs get narrower at one end to fit into the stock spacers, whereas these do not do that - they're consistent width from end to end.  That wouldn't matter using the spacer material the springs came with, however. 

Edited April 15, 2021 by Wintersdark

[Wintersdark]

These springs are 317mm in length, though again the instructions straight up say they won't be the same length as the OEM springs.

[peteinpa]

That sucks, I thought Sonic made all their springs to be identical.

[skipperT]

Cut your spacers to length, and drill the holes the same diameter as the ones your stock spacers have. It will not weaken them enough to worry about IMHO. A hacksaw works great and then sand or file the end to be as square as possible.

The stock springs are progressive and your replacements are a standard rate. Another reason for the taper and spacer change that you’ll make. 

if you get a chance, I’d love to see the instructions included with the springs. (I could check their website too I guess...)

-Skip

Edited April 17, 2021 by skipperT

[Wintersdark]

12 hours ago, skipperT said:

Cut your spacers to length, and drill the holes the same diameter as the ones your stock spacers have. It will not weaken them enough to worry about IMHO. A hacksaw works great and then sand or file the end to be as square as possible.

The stock springs are progressive and your replacements are a standard rate. Another reason for the taper and spacer change that you’ll make. 

if you get a chance, I’d love to see the instructions included with the springs. (I could check their website too I guess...)

-Skip

Aaaah I see!   The stock progressive springs helps explain the wierd behavior I've been noticing since replacing the rear shock and getting it set up properly.  I can't get front sag anywhere near in spec as it stands, and this results in a weird thing where the front will just loosely collapse before firming up.  The rear will compress and extend properly and feels consistent, while the front feels ever so mushy.  It's funny how it wasn't really noticeable to me till getting the rear sorted.

[Wintersdark]

Emailed Sonic Springs just to ask, and yeah they say these springs should work as drop in replacements.  So I guess I'll go that way, see how the preload gap looks with the stock spacers.  If it's either not right or they don't fit right... Well, I'll figure something out to cut custom spacers.