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Hi ,I have a 450EXC 2009 model which has the standard rear spring. Looking in the manual its rated up to a weight of 79kg or so. I'm 6 foot 6 and 100kg .The bike rides fine but will it make a big difference fitting a heavier duty spring? Thanks:smokin:
 

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If its not bottoming out id leave it, soft is nice. 100kg is not that heavy compared to most, id go more for a tall seat and bar risers for your height, bud
 

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Have you checked your rear sag? I've got a 16 stoner spring on the back of my bike (bought it with it already fitted honest! :rolleyes:) I must admit it does feel better as the back end doesnt bottom out of big bumps, have a look under the rear fender if there are tyres marks on it or on ya exhaust then you should think about swapping for the well built spring ;):)
 

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^^^^^^ thats a nice car in your sig pic
 

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Im about changing my rear spring as the 250sxf i ride bottoms out on any jumps, ive ripped off two acerbis rear lights allready, i did buy a heavier duty spring on fleabay which i thought may do the job my it still bottoms out, ok on enduro's but when im out on the mx track it still bottoms..

Edited to add im not fat i have heavy bones.... :)
 

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I am looking into this also, not too keen on a stiffer spring as when out trail riding soft was nice I have wound up the preload to correct sag and it now feels like it bounces a bit worse out on the trail
 

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I am looking into this also, not too keen on a stiffer spring as when out trail riding soft was nice I have wound up the preload to correct sag and it now feels like it bounces a bit worse out on the trail
Get a progressive spring ;)
 

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I weight about 18stone (FB) and OTR (chris) fitted a progressive sprive on my rear shock, put heavier springs in the forks. I also have the Ktm PHDS and the bike does not bottom out now . I do have a couple of springs in the garage, one is brand new one is used, not sure what weight they are , but can look if you want.

Get your self a sag scale and see if its set up ok with your weight etc. If not if if you need some advise , I would recommend Chris at OTR. He is in Cumbria. I knoiw a fair few guys on the forum know him and have used him


My bike is the Excr 400
 

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I weigh 110kg in kit. I had an 86 rear spring on my 2004 450.
All the settings and sag were good but it still bottomed off H&H level of jumps.
Increasing preload to compensate for the jumps left the back feeling harsh and it didn't cure the bottoming out completely.
I bought an 85/110 spring from a member here.
Sag was perfect as fitted and the bottoming has been cured.
 

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Well i aint saying how much i weigh ( Broken legs will only take the P again ;)) but a heavier rear springs does help.
 

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I weigh 110kg in kit. I had an 86 rear spring on my 2004 450.
All the settings and sag were good but it still bottomed off H&H level of jumps.
Increasing preload to compensate for the jumps left the back feeling harsh and it didn't cure the bottoming out completely.
I bought an 85/110 spring from a member here.
Sag was perfect as fitted and the bottoming has been cured.
Sorry for being dull but can you explain what the numbers mean, after a bit of jumping today I guess its something for me that needs sorting but want to know what its all about. Would I need to do front springs as well as rear... How hard is it to do???.... What costs are involved??? Wheres best to get springs from??
 

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You''ll see numbers on a spring. Typically (on a 2004 450 exc) it would be 76-250.
(someone else will surely explain this better.)
250 is the length of the spring. 76 is the strength of the spring and refers to the resistance over the distance the spring moves. The higher this number is, the greater the resistance, so 86 is a 'stronger' or 'harder' spring than a 76.
If the numbers are shown as 85/110-250, this is a 'progressive spring'. 85 is the lower starting rate just as the spring starts to compress and 110 is the higher finishing rate when the spring is compressed towards the end of its movement.
It means that the rear wheel can move fairly easily (soft) at the beginning of its arc but resistance increases (hard) towards the end. It compensates, somewhat, for the linkless system that KTM uses.
Replacing a rear spring is so simply. Once the shock is off the bike, loosen the allen screw in the slotted ring at the top of the spring. Wind the ring back until there is sufficient space to remove the collet and retaining ring from the bottom of the shock.

A rear spring can cost about £85 new.

I've not changed the front springs. I like mine the way it is with only some adjustments to the damping. Changing the rear spring, thus correcting ride height and sag, set the attitude of the bike and the front works better as a result
 

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I've just bought a set of heavier springs for my 250 EXC, 90N for rear and 4.6 for front, so I'll let you know how it is!! I'm 16 stone and 6-6....after the reading the manual I got on the phone to K-Tech :)
 

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You''ll see numbers on a spring. Typically (on a 2004 450 exc) it would be 76-250.
(someone else will surely explain this better.)
250 is the length of the spring. 76 is the strength of the spring and refers to the resistance over the distance the spring moves. The higher this number is, the greater the resistance, so 86 is a 'stronger' or 'harder' spring than a 76.
If the numbers are shown as 85/110-250, this is a 'progressive spring'. 85 is the lower starting rate just as the spring starts to compress and 110 is the higher finishing rate when the spring is compressed towards the end of its movement.
It means that the rear wheel can move fairly easily (soft) at the beginning of its arc but resistance increases (hard) towards the end. It compensates, somewhat, for the linkless system that KTM uses.
Replacing a rear spring is so simply. Once the shock is off the bike, loosen the allen screw in the slotted ring at the top of the spring. Wind the ring back until there is sufficient space to remove the collet and retaining ring from the bottom of the shock.

A rear spring can cost about £85 new.

I've not changed the front springs. I like mine the way it is with only some adjustments to the damping. Changing the rear spring, thus correcting ride height and sag, set the attitude of the bike and the front works better as a result
Cheers for that explanation. I think its a must do.. soon
 
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