Jump to content
Sign in to follow this  

Trust the RaceTech Spring Rate Calculator?

Recommended Posts

I'm looking to do a simple suspension upgrade on my 2004 DRZ400S. According to the RaceTech spring rate calculator, the rear is sprung OK for my weight (165 + gear, oversize tank, DirtBagz+tailbag with crap in it, easy trail riding), but the front should be 0.48 (0.44 is stock).

I've read a bunch of posts and get the impression that RaceTech tends to suggest a rather firm spring rate. John C. (mod) updated a local guys DRZ and only used 0.46s. The other guy outweighs me by 50 pounds.

So I'm on the fence regarding spring rate. Should I trust RaceTech and get the 0.48s or use the 0.46s for a plusher ride. BTW, my use is 50/50 street versus dirt with the dirt being pretty mellow.

Share this post


Link to post
Share on other sites
I'm looking to do a simple suspension upgrade on my 2004 DRZ400S. According to the RaceTech spring rate calculator, the rear is sprung OK for my weight (165 + gear, oversize tank, DirtBagz+tailbag with crap in it, easy trail riding), but the front should be 0.48 (0.44 is stock).

I've read a bunch of posts and get the impression that RaceTech tends to suggest a rather firm spring rate. John C. (mod) updated a local guys DRZ and only used 0.46s. The other guy outweighs me by 50 pounds.

So I'm on the fence regarding spring rate. Should I trust RaceTech and get the 0.48s or use the 0.46s for a plusher ride. BTW, my use is 50/50 street versus dirt with the dirt being pretty mellow.

I would get the .48 and put ONE in with a stock spring. That will give you .46 rate. Then try both .48. If you are puting a bigger tank on I suspect the .48 will be better?

Those bikes come grossly undersprung on the forks. ALL the 450 MX bikes come with .46-.49 STOCK and they weigh about 70lbs less than the DRZ!

Share this post


Link to post
Share on other sites

I'm wondering about the same thing. I have an IMS 3.2 Gal tank. That's only half a gallon more than stock (roughly). With fuel weighing about 7lbs per gallon, it hardly seems worthwhile to select the "oversize gas tank" option. Not to mention the plastic tank weighs less than the stock metal tank.

I'm about 210 lbs in my birthday suit. Gotta figure at least 30lbs additional for boots, gear and a Camelback. I ride mostly trails.

Race Tech suggests .486 (.48) for the front and 5.7 for the rear (based on 210 lbs w/o gear). The stock rear is 5.5. Will the 5.7 make that much of a difference?

Anyone near my weight want to "weigh in" on DRZ springs :thumbsup:

Tipsy

Share this post


Link to post
Share on other sites

your fuel is carried high so you should add it on the generator.0.2 does make a decent difference on spring rate.

Share this post


Link to post
Share on other sites

I weigh 230. I went with Racetech's spring rate suggestions. I'm sooooo happy with the results!

Share this post


Link to post
Share on other sites
your fuel is carried high so you should add it on the generator.

I don't claim to have all of the answers but the way I see it, a pound of lead weighs the same as a pound of feathers.

If my IMS tank weighs a few pounds less than the stock tank and it holds a few pounds more fuel, I don't see what relevance there is in selecting "oversize gas tank" option in the calculator.

Tipsy

Share this post


Link to post
Share on other sites

it also depends on how high the fuel is carried, as higher up gives more leaverage over the forks.

Share this post


Link to post
Share on other sites

Sounds awful stiff. I used .42 kg fork springs on my KTM 525EXC and loved them. I weigh 180. Bike was used for offroad racing. I tried .44kg springs and them bike was better in sand whoops but really sucked in corners and elsewhere. Wouldn't setup for the corner.

Dwight

Share this post


Link to post
Share on other sites
I would get the .48 and put ONE in with a stock spring. That will give you .46 rate. Then try both .48. If you are puting a bigger tank on I suspect the .48 will be better?

Those bikes come grossly undersprung on the forks. ALL the 450 MX bikes come with .46-.49 STOCK and they weigh about 70lbs less than the DRZ!

Great idea because the spring calculators have generalized assumptions that may not fit your type of riding and style.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×