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CRF150RB fork swap results

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Well I went and did it. What a project. Here is the workup with notes and photos:

https://docs.google.com/document/d/1mEsw891e5HUdLIrq4yYQzm2QCsRgK-ihDkrL_fu7_iA/pub#h.47ku05gnek93

Many thanks to Ramz for his research, development, and documentation work. Without his guide there is no way I would have even considered taking on a project like this.

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I finally got to ride on my standard trails. Bottom line: While a fun and interesting project, I currently do not believe the CRF150RB fork swap was cost effective. I reserve the right to change my mind in the future.

More details here including my subjective rating chart comparing the upgrades

https://docs.google.com/document/d/1mEsw891e5HUdLIrq4yYQzm2QCsRgK-ihDkrL_fu7_iA/pub#h.1yyh0apcbr08

Bruce told me he does not think this is a worthwhile upgrade and I am currently thinking the "Fork Whisperer" is right.

Edited by RedMesa
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Best forks and their setup depend a lot on terrain and a rider's expectation; which is why the damper rod vs cartridge and USD vs conventional debates continue. 
IMO the good news is the fork discussions seem to be more rational and objective than the autoclutch or oil threads.

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I have been running this setup for a couple years but lucked out on someone selling the full set off of their bike, so it didn't cost a terrible amount. It is not a cheap mod and not a straight forward mod because you will have to buy springs for your weight, and the springs, fork oil viscosity, fork oil height, shim stack mods, etc are not sorted out at all yet. I hope that more people do this mod though so that we can share details about how best to set the forks up. What I'm running now seems to work but the rebound is all the way open and the compression is all the way closed. Not sure if that's ideal or what but it works for me.

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I have 150R forks on my XR218, and several on this forum have them on their 230s.  There is another recent thread on this forum about revalving & springs for 150R forks.

Those clickers are just bypass bleeds and only good for fine tuning. On my X I needed to run with them both all the way out but the bike would then wallow like an old car with bad shocks so I needed softer valving and less clicker.

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2 hours ago, xplodee said:

I have been running this setup for a couple years but lucked out on someone selling the full set off of their bike, so it didn't cost a terrible amount. It is not a cheap mod and not a straight forward mod because you will have to buy springs for your weight, and the springs, fork oil viscosity, fork oil height, shim stack mods, etc are not sorted out at all yet. I hope that more people do this mod though so that we can share details about how best to set the forks up. What I'm running now seems to work but the rebound is all the way open and the compression is all the way closed. Not sure if that's ideal or what but it works for me.

My stock Cr85 forks where comp full soft/ rebound turned in 3 full turns. Very fast rebound on this fork with .40 spring.

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4 hours ago, Chuck. said:

Those clickers are just bypass bleeds and only good for fine tuning. On my X I needed to run with them both all the way out but the bike would then wallow like an old car with bad shocks so I needed softer valving and less clicker.

The story is just starting. Lots of work to do. 

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Sounds like you may have plenty of revalving practice in your future if you are set on making the forks all that they can be.

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On 7/24/2017 at 7:26 PM, xplodee said:

Redmesa- i love that youre detailing all of this so cleanly. How much do you weigh?

Thanks for the feedback, appreciate it.

I weigh 178 lbs. Ride weight is 225 lbs in full armor with hydration pack. Chainsaw takes it up to around 242 lbs.

I worked up the budget spreadsheet, see the link near the bottom. Wow. That's a lot of money. But they look good! ;)

Also I added notes on fork fluid amount and levels. I had to remove fluid to get the right level. Can anyone explain this mystery? 

https://docs.google.com/document/d/1mEsw891e5HUdLIrq4yYQzm2QCsRgK-ihDkrL_fu7_iA/pub#h.47ku05gnek93

Edited by RedMesa

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Apparently I left air in the forks. Updated with info from Ramz.

This morning I finally did sag measurements: 

https://docs.google.com/spreadsheets/d/14vcNIxgkdRPSc4lmBMNuzQxLpV6VjGyVSTXRHtRDKrQ/pubhtml#

click on “Forks150” tab at top

Even with the Cannon 0.42 springs, the race sag is 3.2 inches. This is like the stock forks with Triplett-modifed springs.

With the stock forks and BBR springs I was able to get it to 2.0 inches which was a big improvement.

So valving aside, this data suggests my spring rate is off. Or maybe some preload?

Edited by RedMesa

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On 7/24/2017 at 7:26 PM, xplodee said:

Redmesa- i love that youre detailing all of this so cleanly. How much do you weigh?

I finally got the sag dialed in by going to the stiffest Cannon springs available: 0.50

Here is the curve. The 0.42 springs were pretty far off.

More details here:

https://docs.google.com/document/u/1/d/1mEsw891e5HUdLIrq4yYQzm2QCsRgK-ihDkrL_fu7_iA/pub#h.nuf3trdzcw4b

 

2018-0124_Sag Chart.JPG

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2 minutes ago, RedMesa said:

I finally got the sag dialed in by going to the stiffest Cannon springs available: 0.50

Here is the curve. The 0.42 springs were pretty far off.

More details here:

https://docs.google.com/document/u/1/d/1mEsw891e5HUdLIrq4yYQzm2QCsRgK-ihDkrL_fu7_iA/pub#h.nuf3trdzcw4b

 

2018-0124_Sag Chart.JPG

Jaaaas. .50 springs good for 350 pound rider

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Dang RM are you racing or jumping that 230. Even my Xr650R only has .43 springs  also my Wr450f only has .43 springs both on stiff side.  It could be I have not found the other 4 gears. 

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On 1/24/2018 at 3:14 PM, bajatrailrider said:

Jaaaas. .50 springs good for 350 pound rider

Well, lots has happened in the last couple months. BTR and Mike H. both rode my bike and it gave them some ideas.

Some of that is reflected in the post below and others.

I have updated the page here http://bit.ly/2GNQApv including an interesting link to Chuck on rated travel and measured travel: they are not the same. 

 

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15 minutes ago, RedMesa said:

Well, lots has happened in the last couple months. BTR and Mike H. both rode my bike and it gave them some ideas.

Some of that is reflected in the post below and others.

I have updated the page here http://bit.ly/2GNQApv including an interesting link to Chuck on rated travel and measured travel: they are not the same. 

 

I only rode your bike in the wash not many rocks it felt OK. Mike said first half your travel it felt good after that too stiff. . After you told me you have a Chain saw on forks most of the time you ride it makes sense. Another thing to consider your gearing 12/50 so on dirt road your moving very slow in top gear. Ours with 14 or 15/45 go way too fast so we need it to go over rocks at speed. On stiff susp. bikes very bad for me anyway over rocks. Love your flex handle bars.

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