how much of the full travel should forks use?

[Mike5100 2,061]

The new Showa forks on my 2016 bike seem to be using only part of the available full travel.  That's supposed to be 153mm and using zip ties and going over some pretty appalling potholed roads at speed only seems to be using up to 125mm of that travel.  Is that normal?  And if they were adjustable forks what would have been needed to get it to use all the travel available?

Thanks

Mike

[DaveM59 1,605]

Sounds fine, you do not want to be bottoming out so to have some movement spare for extreme impacts or you could damage them.

Even at minimal preload they should be almost impossible to bottom out and as you increase preload, the travel will become less. Damping adjustment should have hardly any effect on travel as it's the springs that support the weight, the damping just controls the speed the spring responds at.

[embee 7,288]

The compressing air gap above the oil gives a rising rate as you approach full travel, so depending on the oil level it may or may not use the last few mm. To reduce the rising rate effect you can use slightly less oil (=more air gap so more compliance).

 

The stock springs in my 700 Integra were progressive, but very soft at the beginning then firming up significantly (something like 6N/mm at first rising to 9 or 10N/mm at full travel). I would guess the other models are the same style spring. I don't like the soft squidgy initial movement so fitted some 9N/mm linear rate springs.

 

There is also a "hydraulic stop" element where a cone shaped part at the bottom of the fork which enters the stanchion and progressively closes off the hole so it gets a hydraulic stop effect which prevents a hard metal/metal bottoming out. I'm not sure how much travels this takes up, but your measured travel is probably not far wrong under nasty road conditions.

[Mike5100 2,061]

The compressing air gap above the oil gives a rising rate as you approach full travel, so depending on the oil level it may or may not use the last few mm. To reduce the rising rate effect you can use slightly less oil (=more air gap so more compliance).

 

The stock springs in my 700 Integra were progressive, but very soft at the beginning then firming up significantly (something like 6N/mm at first rising to 9 or 10N/mm at full travel). I would guess the other models are the same style spring. I don't like the soft squidgy initial movement so fitted some 9N/mm linear rate springs.

 

There is also a "hydraulic stop" element where a cone shaped part at the bottom of the fork which enters the stanchion and progressively closes off the hole so it gets a hydraulic stop effect which prevents a hard metal/metal bottoming out. I'm not sure how much travels this takes up, but your measured travel is probably not far wrong under nasty road conditions.

Is this true of the Showa SDBV fork Murray do you think?  I like the softness of the first part of the travel, so the springs seem OK to me.  Is it possible to simply take the top caps off and pipette a bit of oil out of each fork, or does it need a strip down.  I am a bit nervous that the oil level was set incorrectly in the factory, but IIRC you have to measure that gap with springs removed so that would mean a stripdown.

Mike

[Griff 1,556]

This is a sore point with me in relation to the recent fitting of my Andreani cartridges. My method of checking max travel using a zip tie,  involved braking really hard using front brake only to the point of almost getting the rear wheel off the ground. Using that method I have found my NC700 forks have approximately 120mm of travel give or take a few mm. Being aware that I should have 153 mm I took this up with Andreani. They advise that the travel as advertised by Honda is less than accurate and that 120mm is closer to the real travel figure. They may or may not be correct in this.

 

 At this point there might be some others out there who have tested and measured. If so perhaps we could get a consensus on this issue.  

[embee 7,288]

I don't know the details of the new Showa forks. Principles are probably the same regarding oil levels but I don't know where the valves sit.

[Mike5100 2,061]

This is a sore point with me in relation to the recent fitting of my Andreani cartridges. My method of checking max travel using a zip tie,  involved braking really hard using front brake only to the point of almost getting the rear wheel off the ground. Using that method I have found my NC700 forks have approximately 120mm of travel give or take a few mm. Being aware that I should have 153 mm I took this up with Andreani. They advise that the travel as advertised by Honda is less than accurate and that 120mm is closer to the real travel figure. They may or may not be correct in this.

 

 At this point there might be some others out there who have tested and measured. If so perhaps we could get a consensus on this issue.  

Sounds good Griff.  However on the new Showa forks, Honda claim they have anti-dive properties under braking so if they actually work one wouldn't achieve anywhere near full travel using your technique.  I have been testing mine by deliberately aiming at big potholes and taking speedbumps at a fair lick, but I confess this may not be as much as Honda expect the fork to be compressed every now and then, so there may still be some headroom.

Mike

[scara 354]

Lets hope one of the big potholes you are aiming for or the speedhumps you take at a fair lick don't end up putting you on your arse and the bike down the road. That pothole might be deeper than you think.

[Scousus Maximus 1]

Can't you put the bike on a bench and use ratchet straps to compress the springs? I might be way off course here so if somebody clevererere than me says NO then that's fine.

 

Regards,

 

John