KTM WP Forks on AT

[diskow]

I have a chance to buy and I am interested in WP forks 48/60 from KTM LC4 640 SM. I presume original springs from this model are not enough for offroad use with AT... Has anybody ever use those mentioned forks on AT? Experiences? Thanks for all the answers and help.

[scarfacehugo]

Originally Posted by diskow

I have a chance to buy and I am interested in WP forks 48/60 from KTM LC4 640 SM. I presume original springs from this model are not enough for offroad use with AT... Has anybody ever use those mentioned forks on AT? Experiences? Thanks for all the answers and help.

I believe SM forks have less travel, the yokes are wider and the brake caliper stays lower than off road bikes.
All these 3 points are not good for off road. I bet they're great forks if you dont do off road.

[BobA]

Check out "Garage Nights" episode 11 & 12, this will give you some ideas.


They tried to use the SM forks for a BMW, but discovered plenty of problems.


Ep 11: KTM forks on a BMW F650 at Garage Night

Ep 12: KTM forks on a BMW part 2 at Garage Night



Keep us updated on how you proceed please.



Good Luck



Bob

[futter]

Originally Posted by scarfacehugo

I believe SM forks have less travel, the yokes are wider and the brake caliper stays lower than off road bikes.
All these 3 points are not good for off road. I bet they're great forks if you dont do off road.

Depending on which forks they are the same - also the same as the 525. The calliper still sits on the top half of the disc. The standard disc is 300 mm the SM item is 320. 10mm larger is not much.

[Stormforce8]

Hi diskow

I've just swapped out my forks for a set of WP48s from a KTM 990 Adventure.

Here's some pics of a conversion that we did earlier this year with WP48s from a KTM 950 Adventure



You can use pretty much any of the LC4 or LC8 forks but I would tend to agree with Scarfacehugo and BobA in that I wouldn't go for the supermoto or Duke ones as they have a shorter stroke.

Any of the Enduro, Six Days, or Adventure models are a good swap. The only thing that requires reworking is the head stem - get a new one machined from solid bar.

You will definitely need to uprate the springs - a good place for these is Slavens Racing - speak to Jeff.

The brakes are easy - and if you can, just swap the whole system over with the Brembo master cylinder as well.

If you are using a single disc conversion you can run a 320mm disc with a four pot caliper if you really want to - you'll just need to buy a caliper bracket - one of the chaps off the KTM Forum sells them on Ebay. (this is the system that we're in the process of fitting to Chad's Toxic conversion)

[scarfacehugo]

Originally Posted by Stormforce8

v




You will definitely need to uprate the springs - a good place for these is Slavens Racing - speak to Jeff.

Hi!
Just one quick question. What rate springs are you using on yours?

I've got 5.0 and they're still too soft.

[diskow]

Thanks for all the help.
I will think about it and reconsider again before i buy anything.

[Stormforce8]

Originally Posted by scarfacehugo

Hi!
Just one quick question. What rate springs are you using on yours?

I've got 5.0 and they're still too soft.

I basically gave the total 'wet' weight of the bike, my weight, and the type of riding I'll be doing on it to Jeff and he came back with his recommendation.
Unless you're a little lightweight - or have enjoyed too many pies, you'll probably require between a 52 or 56 kg/mm spring for an AT

[atgreg]

Originally Posted by scarfacehugo

Hi!
Just one quick question. What rate springs are you using on yours?

I've got 5.0 and they're still too soft.

when Iput CR250 USD's on my AT I used 0.58 springs but Im pretty heavy

[diskow]

Originally Posted by Stormforce8

You can use pretty much any of the LC4 or LC8 forks but I would tend to agree with Scarfacehugo and BobA in that I wouldn't go for the supermoto or Duke ones as they have a shorter stroke.

Let me know if that means anything more to you for an opinion if this would be ok or more?
- Forks are WP. model 48/60. 48mm diameter/265mm extension
- from KTM model LC 4 640 SM
- The springs are original
I have pictures too but i dont know how to upload it.

extensions on regular lc4 640 is only 5 millimeter longer. Together 270mm
Is there any disadvantage in offroad use if the yokes are wider than normal?


Thanks