Race Tech Fork Spring

voltman_rc · Sep 29, 2007

Has anyone tried using a Race Tech FRSP 375046 (.46 kg/mm) set of fork springs on an E series (specifically 1989) KDX. The Race Tech website specifies them as a replacement for the bike but Parts Unlimited says the KDX is an exception. I need confirmation before ordering a set. My other option is to order a set from Fredette but they only show up to .42 kg rather than .46.

TheGDog · Sep 29, 2007

I'm gonna subscribe to this threed too. I've got a 1990 that I need to beef-up the springs on too, so I'm in the exact same boat. And currently I'm pushing like 210 Lbs.

Thanks man,

TheGDog

112690 · Oct 1, 2007

I would suggest working with Fredette. Rumour has it that the race-tech suggestions are two stiff. I have a KDX220 and installed .38 springs. That was sufficient for me, BUT, I'm a 205#, 53 year old that like the challenges of tight eastern woods and hills. No high speed fireroads and MX doubles for me.

I also noticed that the compression damping is a little stiff after the swap. I used 7 wt oil. I am planning on installing the race-tech valves in the near future to correct. You could use 5 wt oil to help.

ronnie l · Oct 1, 2007

112690 said:
I would suggest working with Fredette. Rumour has it that the race-tech suggestions are two stiff. I have a KDX220 and installed .38 springs. That was sufficient for me, BUT, I'm a 205#, 53 year old that like the challenges of tight eastern woods and hills. No high speed fireroads and MX doubles for me.

I also noticed that the compression damping is a little stiff after the swap. I used 7 wt oil. I am planning on installing the race-tech valves in the near future to correct. You could use 5 wt oil to help.

Is that 205lbs with your riding and boots on?

teller county rydr · Oct 1, 2007

I got the up rated springs from Fredette but my tuner had to preload them up to a real 4.2 because they tested softer than spec. With the front fork valves redone at the same time it now works perfect. I rode my 05 KDX 220 on the Colorado 500 in August and did the Fay Meyers Awsome Autumn 250 this weekend between Sedalia CO and Salida CO and back. On rocky trails it feels great and very controllable.
Overall I think it feels a little skittery because its so lightweight but I'm getting used to it.

D_Moen · Oct 1, 2007

205 lbs here, just installed Fredette's .40s and did the "shim-stack" mod. I'm very happy with the results for riding in tight technical stuff. I sure wouldn't go with harder springs....

glad2ride · Oct 2, 2007

voltman_rc, what is your weight in full riding gear, skill level, type of terrain (smooth trails, tight, rocky, rutty trails, MX track, etc.)?

Have you changed the shock spring?

112690, do you know if you have the stock amount of preload? If so, then that will contribute to your compression damping problem (besides going with 7 wt instead of 5 wt).

If you have a 1989 - 1992 KDX200, then the stock rate is a whopping .30!! ANY stiffer rate will make you think you are in the big time, but DO get the correct rate for your weight / skill level / terrain.

voltman_rc · Oct 2, 2007

I ended up ordering a set of .35 take offs for my 89 KDX from Fredette as well as a 4.8 rear spring (one size heavier than stock). My weight will be 220 and I mostly ride trails and gravel pits. They said that any stiffer on the front would be way too much for me. The main reason for changing the rear spring is that a previous owner actually put a lighter spring in and I didn't get the stock spring with the bike.

Thanks for all the feedback.

glad2ride · Oct 16, 2007

.35 is going to be too soft for you, but better than stock. If you ever ride one with .40's or .42's, you would be surprised.

Race Tech Fork Spring

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