fork spring rate 03 Lemans

[BillyB]

I searched but didn't find much info - what spring rates are you guys running, when you upgrade your Marzocchi springs? I've seen references to 0.9 and 1.0 but no reference to rider weight. I measured my sag and have 1.5" of static (bike only) sag, and then 1 7/8" with me sitting on the bike. I want to get the front end in the right ballpark without spending much money on it because I'm honestly not sure how long I'll keep this bike - it may get replaced down the road with something more comfy for my wife to ride on back. Anyways I'm hoping to get the correct springs in there and maybe some heavier fork oil if that works to improve the damping in the Zokes? I'm about 180lbs without gear.

I'll be buying an aftermarket shock rather than trying to make the stocker right.

Thanks all.

[docc]

Your spring supplier should be able to spec the rate and the preload spacers for you. Traxxion Dynamics spec'd mine and nailed it perfectly.  I have the earlier Sport without the LeMans faring and different (smaller) forks than yours, so my numbers probably don't contribute much.

As for fork oil, these forks do not damp spectacularly and many have found lighter oil flows better through the valving. There was a very well crafted, recent post that spoke of selecting fork oil in centiStokes, rather than SAE "weight" which has tremendous variation and overlap between manufacturers.

[docc]

Here it is, from respected member @O2 V11:

 

[BillyB]

I'd think .95s are available so it seems odd they went with a 1.0 in one leg and a .9 in the other. I'll check with Traxxion, sounds like they'll advise the 0.9s.

I'll find the post regarding oil weight also. Thanks again.

[Kane]

Hi Billy,

please post what you find out! I too am putting in new spings and am wondering the same thing. I'm not doing the valving at this point, just new springs, light oil, and an Ohlins shock off of a Scura. Those three changes should be a decent improvement. 190lb. solo rider here.

 

Cheers

[BillyB]

Traxxion said they don't have springs to fit without buying their high $ cartridge kit which I'm not interested in. They did suggest a 1.05 rate if I can find springs to fit the stock internals, seems heavy but I suppose all the bikes I've put springs in before have been lighter bikes so maybe he's correct. I'll try Race Tech next.

Essentially what I got out of the oil weight post is to go with 7wt, barring all the details regarding the actual viscosity of 7wt differing between brands.

[docc]

Peter Verdone produced a conversion chart of numerous popular fork oils showing the more accurate and reliable cSt unit. 

http://www.peterverdone.com/archive/lowspeed.htm

[BillyB]

Race tech said .90s should be correct for my 180lbs w/o luggage. I'll order those and report back after it's together.

[nobleswood]

Just to add information  not as a dictate, when I changed the springs on my Griso, which is a similar weight, I installed 1.05 kg/mm Traxxion springs. The Griso has Showa forks & with all the gear I ride with I'm at 200 lbs. This allowed me to get the sag settings I was looking for, 35 mm at the front.

Initially I bought a 0.95 kg/mm spring which was too light & Traxxion swapped it for me, costing me freight only.

Remember as well as changing the oil weight, the air gap needs to be precise 

[BillyB]

Quick update - after I ordered the .90 springs from Race Tech, I found somewhere online saying the stock springs are .86, so the .90 didn't seem like enough of a difference so I shipped those back and ordered .95s. This took longer than expected (Race Tech lost the springs I sent back and took 2 weeks to find them). Anyways they sent the .95s and I went to fit them last week and they won't work. They're a lot longer than the stock springs and the travel stop on the damper rod was hanging up on the junction between the spring and spacer. I just called Race Tech back and they don't know who suggested the springs I bought, but confirmed that the correct spring for this Marzocchi 43mm fork is their S3827 series spring. They're shipping those out today.

I realize this was a terrible explanation of the issue but hopefully the picture helps. On the bottom is the stock spring/spacer, and installed on the top damping unit is the (wrong) Race Tech spring/spacer. You can see how that little collar on the damping rod will be hanging up on the inside of the spring/washer/spacer, especially since the spring they sent is smaller in OD than the stock one and has room to move around inside the fork tube. The new spring they're sending is a larger OD, similar to the stock spring.

In the meantime I got a new MShock mounted up in the back so I'm looking forward to getting the front end together again finally, just in time for winter to set in!

[nobleswood]

BillyB 

from my experience with Ohlins, Racetech & Traxxion in that order. Some companies have a lot bigger clients & accounts to deal with & they aren’t going to make much $ from our modest purchases. Hence the service you receive can vary from which technician you get on the phone, so if you find a knowledgeable & helpful tech, write his number down & share it with us 

So for those following in your footsteps that Racetech spring number helps & saves others from techs not paying as much time as they should. 👍

[cash1000]

I had Racetech Springs & valves fitted a few years ago

From invoice springs fitted were 260Lx25.5IDx35.3OD 1.0Kg/mm

I'm 100 kg plus 10kg of gear.

I've just replaced fork oil and found I needed to build a fork compression tool to be able to completely drain the forks

I copied one from Racetech's website 

[BillyB]

I realize I'm moving in slow motion on these forks - busy time of year for me. Anyways, I have the correct springs now from Race Tech - they're almost the same diameter/length as stock and fit well now.

As for the air gap, I searched around and don't see a consensus on the amount of gap. I've used 100mm in the past for several forks (fully compressed with no spring/spacer). Searching on this site people seem to use anything from 100mm to 120mm. I'll go with 110mm unless someone has good info saying otherwise? Thanks.

[Lucky Phil]

3 hours ago, BillyB said:

I realize I'm moving in slow motion on these forks - busy time of year for me. Anyways, I have the correct springs now from Race Tech - they're almost the same diameter/length as stock and fit well now.

As for the air gap, I searched around and don't see a consensus on the amount of gap. I've used 100mm in the past for several forks (fully compressed with no spring/spacer). Searching on this site people seem to use anything from 100mm to 120mm. I'll go with 110mm unless someone has good info saying otherwise? Thanks.

Why not add the manual recommended quantity of oil and then measure the gap? Then you'll know your in the ballpark.

Ciao

[BillyB]

Phil, I like the air gap method because a few times in the past (other bikes) I've thought I drained the forks completely and when I put in the measured amount of oil, it was way off (too much). Anyways I set it to 110mm.

I just took the bike for a spin and the M-Shock seems really nice right out of the box. The forks seem like they have too much compression damping and not enough rebound. I didn't have the time to check sag or fiddle with the rebound adjuster and take another ride. Ah... just dawned on me... now that I'm typing this and think of where I set rebound at, its all the way backed out on both forks because I did this to take it apart and forgot to set it back to something reasonable. That likely solves that issue! There is no compression adjustment on these forks so I'm probably stuck on that unless I want to put lighter oil in. I used 7 weight and could go to 5wt but that's not likely to happen until the next fork seal blows