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Re:Fork oil change - question
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TOPIC: Re:Fork oil change - question
#957069
jd750ace (User)
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Re:Fork oil change - question 1 Year, 7 Months ago  
With stock springs, consider the fact that 10W is double your stock fluid viscocity with no increase in spring tension. If the spring overwhelms the damping, you get a hobby horse. If the damping overrides the spring, you get a rough ride and tires not staying in contact with the road. 10W is a conservative but worthwhile boost, but also understand that what it is doing is controlling an underrated spring and keeping it from blowing through all your travel. Stock springs are perfect for a 155 pound rider. Stick with 10W if you are keeping the stock springs. I only recommend keeping the stockers (with a modification or two) if you are 185 pounds or less and mostly ride solo.
 
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Re:Fork oil change - question 1 Year, 7 Months ago  
Listen to JD he walked me through mine!
 
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#957086
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Re:Fork oil change - question 1 Year, 7 Months ago  
jd750ace wrote:
1 or 2mm is nothing to be concerned about. As far as your fluid expiriment, I'd be more inclined to make sure your rebound is not too slow. Compression wise, it'll probably be OK, if not a little stiff on smaller bumps. People HAVE used 20W in the past with the stock tubes. Have not ridden it myself, but just based on the dynamics of the stock fork, rebound would be where I would focus. Indications of excessive rebound damping would be the front packing down on bumpy curves, wbicb will have the charateristic of having to correct wider as you hit the bumps. Deeper compression of the tube tightens the turn radius. The other place is braking over ripples. Excessive rebound damping will have the characteristic of wheel hop, where the fork is not extending the fork back out fast enough on the down slope of a bump. It can be felt as a chattering effect, both in the bars and in the lever, as the pressure required to stop the front wheel will spike up and down as the tire goes in and out of contact with the road. If you check for this, do it solo, in an area where the stop is not mandatory, and you can let go of the brake to recover if you experience a lockup chirp or something. I don't expect you to have a big issue, but I would do the experimemtation up front. Better at a controlled time than in the moment to assess the performance.

Thanks, JD. I'll do that first chance I can. Really appreciate your insights and knowledge, as always!
 
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Re:Fork oil change - question 1 Year, 7 Months ago  
I really got to get around to changing out the fork oil. My front end dive under braking is terrible.
 
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Re:Fork oil change - question 1 Year, 6 Months ago  
jd750ace wrote:
1 or 2mm is nothing to be concerned about. As far as your fluid expiriment, I'd be more inclined to make sure your rebound is not too slow. Compression wise, it'll probably be OK, if not a little stiff on smaller bumps. People HAVE used 20W in the past with the stock tubes. Have not ridden it myself, but just based on the dynamics of the stock fork, rebound would be where I would focus. Indications of excessive rebound damping would be the front packing down on bumpy curves, wbicb will have the charateristic of having to correct wider as you hit the bumps. Deeper compression of the tube tightens the turn radius. The other place is braking over ripples. Excessive rebound damping will have the characteristic of wheel hop, where the fork is not extending the fork back out fast enough on the down slope of a bump. It can be felt as a chattering effect, both in the bars and in the lever, as the pressure required to stop the front wheel will spike up and down as the tire goes in and out of contact with the road. If you check for this, do it solo, in an area where the stop is not mandatory, and you can let go of the brake to recover if you experience a lockup chirp or something. I don't expect you to have a big issue, but I would do the experimemtation up front. Better at a controlled time than in the moment to assess the performance.

Finally had a chance to get it out and take her for a spin (thanks to some lovely weather).

Pretty happy with it - a touch stiffer, corners well, no problems braking. The only problem is that I didn't get it out on a highway - our major north/south throroughfare out of the city is closed for construction today, so I was driving around in town. Curious to see what happens when I get it on the highway and 2-up, the way I usually ride.

On a different note, quite pleased with the Cobra Powerpro HP. Deeper and just "better" (hard to explain, less raspy/blatty) than the V&H Long Shots, and the performance difference is noticeable. Really can't wait to open it up on the highway and see how the top-end of 5th is affected.

Have a great weekend folks - and thanks again for the advice JD!
 
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Re:Fork oil change - question 2 Weeks ago  
jd750ace wrote:
With stock springs, consider the fact that 10W is double your stock fluid viscocity with no increase in spring tension. If the spring overwhelms the damping, you get a hobby horse. If the damping overrides the spring, you get a rough ride and tires not staying in contact with the road. 10W is a conservative but worthwhile boost, but also understand that what it is doing is controlling an underrated spring and keeping it from blowing through all your travel. Stock springs are perfect for a 155 pound rider. Stick with 10W if you are keeping the stock springs. I only recommend keeping the stockers (with a modification or two) if you are 185 pounds or less and mostly ride solo.Is 20wt a totaly BAD idea ?
 
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#1023681
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Re:Fork oil change - question 2 Weeks ago  
I wouldnt go more than 15wt. If your wanting to go with heavier oil to reduce nose dive then your problem is the springs. Get stiffer springs. The oil acts only as a shock.
 
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Re:Fork oil change - question 2 Weeks ago  
smokescreens wrote:
I wouldnt go more than 15wt. If your wanting to go with heavier oil to reduce nose dive then your problem is the springs. Get stiffer springs. The oil acts only as a shock.Does heavier oil equal heavier duty shocks ?
 
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#1023687
jd750ace (User)
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Re:Fork oil change - question 2 Weeks ago  
No. Matched heavier springs and heavier oil equals heavier duty capacity. Bear in mind the damping hole diameters are not ideal for heavier springs and oil. It IS a vast improvement, but Race Tech emulators are the way to tune your damping to the heavier springs, specifically if you are 1/8 ton or more solo.
 
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