rhb Posted May 10, 2017 Share Posted May 10, 2017 I'm a researcher. If I don't know something about an upgrade, I read everything I can about it before deciding to buy something, call it methodical or whatever. when searching about info on front fork upgrades, the various solutions, cost etc. I found a lot of conflicting info on the stock front fork springs on the FZ/MT07. I present the following for everyone's benefit and also solicit any informed opinions as well. various unsubstantiated forum posts (not necessarily this forum): "The stock front springs are for a 165 lb rider. If you weigh more than that....you need stiffer springs to stop the front end dive". "I agree the stock forks are not too bad, especially if you are 150 lbs or under". "Traxxion changed the front springs from .9kgs to 8.5kgs for my weight... 165 pounds with gear" : Now the facts from three trusted sources, but with 2 different opinions. They are three very well known manufacturers and or shops, I won't put them on the spot by mentioning names: vendor A At 175-180 lbs in gear, If your're in the market for front springs, I'd ditch the factory springs and go for the next lower rate of 0.85 kg/mm. the stock rate is 0.875 kg/mm, which is only incrementally firmer. (so splitting hairs) The proper approach to fixing brake dive will be to address the damping. Vendor B we’d recommend trying it with the OEM springs. We rated the OEM springs in the FZ07 at .87 kg/mm. VendorC .875 is good for your weight. Here is the kicker and it goes against the common opinion it seems, I am 175-180 pounds with gear, not a 150 pound Japanese rider. Is it possible the bikes are or have been supplied with different springs in different markets, or are people just mis-informed. Link to comment Share on other sites More sharing options...
Premium Member i28 Posted May 10, 2017 Premium Member Share Posted May 10, 2017 According to http://www.racetech.com/ProductSearch/2/Yamaha/FZ-07/2015-16 "Stock Front Spring Rate: 0.72 kg/mm (stock)" We did have a couple of suspension guys discuss this in more detailhttps://fz07.org/thread/4893/spring-rate?page=2 pattonme: "I measured again (assuming merc16's forks are stock) and came up with 0.79-0.82kg/mm. Link to comment Share on other sites More sharing options...
twotone Posted May 11, 2017 Share Posted May 11, 2017 I'm a researcher. If I don't know something about an upgrade, I read everything I can about it before deciding to buy something, call it methodical or whatever. when searching about info on front fork upgrades, the various solutions, cost etc. I found a lot of conflicting info on the stock front fork springs on the FZ/MT07. I present the following for everyone's benefit and also solicit any informed opinions as well. various unsubstantiated forum posts (not necessarily this forum): "The stock front springs are for a 165 lb rider. If you weigh more than that....you need stiffer springs to stop the front end dive". "I agree the stock forks are not too bad, especially if you are 150 lbs or under". "Traxxion changed the front springs from .9kgs to 8.5kgs for my weight... 165 pounds with gear" : Now the facts from three trusted sources, but with 2 different opinions. They are three very well known manufacturers and or shops, I won't put them on the spot by mentioning names: vendor A At 175-180 lbs in gear, If your're in the market for front springs, I'd ditch the factory springs and go for the next lower rate of 0.85 kg/mm. the stock rate is 0.875 kg/mm, which is only incrementally firmer. (so splitting hairs) The proper approach to fixing brake dive will be to address the damping. Vendor B we’d recommend trying it with the OEM springs. We rated the OEM springs in the FZ07 at .87 kg/mm. VendorC .875 is good for your weight. Here is the kicker and it goes against the common opinion it seems, I am 175-180 pounds with gear, not a 150 pound Japanese rider. Is it possible the bikes are or have been supplied with different springs in different markets, or are people just mis-informed. Go with the advice of vendors A-C, they are not far from the facts, the real issue is the weak damping. .87 stock springs have been tested to be true. You either need imulators or drop in valves from cogent dynamics at a minimum Go to o sonic springs web site and use the spring calculator It's more reliable than racetech Link to comment Share on other sites More sharing options...
rhb Posted May 11, 2017 Author Share Posted May 11, 2017 Since others dropped names, the three vendors in order of listing in my post are Nick @ Stoltec, Todd @ Cogent, and Dan @ Traxxion. I assume they got it right. BTW all three came up with .875 (stock spring rate) one just rounded off. Link to comment Share on other sites More sharing options...
motorazr Posted July 13, 2018 Share Posted July 13, 2018 On 5/10/2017 at 7:05 PM, i28 said: According to http://www.racetech.com/ProductSearch/2/Yamaha/FZ-07/2015-16 "Stock Front Spring Rate: 0.72 kg/mm (stock)" We did have a couple of suspension guys discuss this in more detailhttps://fz07.org/thread/4893/spring-rate?page=2 pattonme: "I measured again (assuming merc16's forks are stock) and came up with 0.79-0.82kg/mm. RaceTech has updated their web site: http://www.racetech.com/ProductSearch/12/Yamaha/FZ-07/2015-17 They now say: "Stock Fork Spring Rate:0.88 kg/mm (stock) Comments: First Year 2015 FZ-07/MT-07 Models may have lighter .75kg Rate Fork Springs" I know can be difficult to distinguish soft springs from soft dampening. As soft as my 2015 front-end is, my static sag is only about an inch and all the spring-rate calculators I've used say I should be using 0.9 kg/mm so my stock springs are probably correct while it's just that my fork oil is way too thin (5wt should be 15wt). I was tortured by the Japanese during the war, Jack. Not a pretty story. Strange thing is they make such bloody good cameras. Link to comment Share on other sites More sharing options...
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