VTEC suspension upgrade / overhaul.

[npat]

Hello everyone.

I live in Athens / Greece. Having clocked approximately 150,000 km all over Europe on my trusty old CBF600S, I replaced it (last summer) with a dark-red VFR 800 VTEC ABS (RC46C / 2006). I bought it second-hand from a friend, with 17000km on the odometer. I ride all year long (the weather here is quite nice, even during most of the winter). I use the bike for commuting and touring. Most of the times I ride without a passenger (though not exclusively) and at quite a spirited pace. Sometimes (during longer trips) I use Givi Side-cases, but more often than not a small tail-pack and and a tank-bag are enough. I mostly ride on twisty back-roads which are not always perfectly paved (bumpy, cracked, rippled, slippery, etc). I plan to keep the VFR for long, so I think a suspension upgrade would be a good investment (paying back in riding pleasure, as well as increased safety).

For the rear suspension, the upgrade is rather straightforward (though quite expensive ). I will replace the stock shock with an Ohlins HO605 (with external reservoir, hydraulic preload, and compression / rebound damping adjustment).

At the front, things are a bit more complicated. I lean towards installing stiffer springs and RaceTech's Gold Valve kits (for compression and rebound). Another option would be a complete axxion cartridge replacement kit, though I think I will not like the price, when I hear it. Finally, if all else fails, I will simply replace the springs with stiffer ones and maybe put a different grade oil (postponing other improvements for a later time).

After this rather long introduction, here are some questions for you:

1. Spring rates: I weight approximately 100kg (220 lbs). I think I will need 0.95kg/mm fork springs and a 19.3kg/mm shock spring. Or should I go for 1.0kg/mm fork springs and a 20.3kg/mm shock spring? Or something else? Keep in mind that the roads I ride are sometimes quite bumpy, so a very stiff setup might not be the best for traction (or am I wrong?).

2. Do you know if Ohlins or WP make fork-springs at these rates suitable for the VFR? (We have well-stocked local Ohlins and WP distributors here, so I could get them without having to wait to much for overseas delivery). If not, does anyone know where I could find springs at these rates for the VFR, in Europe?

3. If I change ONLY the fork springs and oil at the front (no revalving), what grade oil would you recommend? Would that be a TERRIBLE compromise? It's not so much a matter of cost (as I am prepared to pay for RaceTech's gold valves); it's mostly a matter of shipping delays, as I plan a long trip, in a moth or so, and I don't know if this is enough time to have them shipped over here.

4. What static / dynamic sag numbers should I aim for?

5. Any other suggestion you might have would be welcome.

(I posted a similar question here. Sorry for double-posting! Also, sorry if my English is not that good; I hope you can understand this post)

Thanks in advance for your answers, and keep riding!

[PACIFICMAN]

I have basically the same questions about my '02. Your English is excellent.

[Veefer800Canuck]

Your English is better than my Greek. You're probably right about not going too stiff on the spring rate, seeing as how the roads are frequently rough.

And yes You could easily do the stiffer fork springs now, with slightly heavier oil, and wait to do the fork valves later, after your bank account recovers from buying the rear shock.

[npat]

Thanks for you answers.

You're probably right about not going too stiff on the spring rate, seeing as how the roads are frequently rough.

You think 0.95kg/mm front and 19.3kg/mm rear would be reasonable? (I'm trying to increase the rate proportionally at both ends. Does this make sense?)

with slightly heavier oil

You think 15w would be good (since, I believe, the stock is 10w)? I'm a little worried not to make the bike un-ride-able due to too-little rebound damping, or too-much compression damping.

[spud786]

Thanks for you answers.

You're probably right about not going too stiff on the spring rate, seeing as how the roads are frequently rough.

You think 0.95kg/mm front and 19.3kg/mm rear would be reasonable? (I'm trying to increase the rate proportionally at both ends. Does this make sense?)

with slightly heavier oil

You think 15w would be good (since, I believe, the stock is 10w)? I'm a little worried not to make the bike un-ride-able due to too-little rebound damping, or too-much compression damping.

I ran 15 weight in a cr500 one time(standard is 5 weight) and it was excellent all except, uphill whoop sections, the rebound was too slow, this on supercross type obsticals. A street bike will never see that kind of action, so very possible 15 weight Belray, would work outstanding, and superior to the stock Honda SS8.

Now Ive ran a few differnt 10 weights in the vfr, and the SS8(10w) is the best , because its the heaviest , as 10 weights vary amongst brand. By all means try the 15 weight at stock 100mm or drop the oil height 5 mm to 105 oil height. Usually when you go higher on oil weight, it doesnt need as much oil height, but the VFR stock is a very linear progressive fork(too soft), and most need a little more oil height with stock weight oil.

[npat]

drop the oil height 5 mm to 105 oil height.

Huh? You mean RAISE the oil level (and reduce the height of the 100mm air-chamber), or the opposite? I'm confused!

We are always talking about a stiffer (0.95kg/mm spring). Should I:

1. Try a 15w at the same (stock) level?

2. Try a 15w with more oil (smaller air-chamber height)

3. Try a 15w with less oil (larger air-chamber height)

4. Try the stock 10w at the same (stock) level?

5. Try the stock 10w with more oil (smaller air-chamber height)

6. Try the stock 10w with less oil (larger air-chamber height)

Please, don't answer: "YES" :laugh:

[spud786]

I made a typo when I said by all means try the 10 weight, I meant to say 15 weight, and I corrected that. I dont care about air gap, Im stating oil height, standard is 100 mm from the top of tube of a fully compressed fork. With 15 weight Id do the standard 100mm or drop oil height to 105 mm from top of tube.

Hope that clarifies

[npat]

Hope that clarifies

Yes it does.

Is my assumption correct, that using a stiffer spring, I will also need heavier oil in order to compensate for the increased rebound-damping requirements of the stiff spring?

[spud786]

Hope that clarifies

Yes it does.

Is my assumption correct, that using a stiffer spring, I will also need heavier oil in order to compensate for the increased rebound-damping requirements of the stiff spring?

Your getting into a little black magic, but forks with zero preload, lighter weight oils do show up with quicker rebound and vice versa, whether it matters or not in real action is the deciding factor. The Vfr has preload adjustment, so that factors in how that is set up.

But to answer your question, If you go from a Dual rate spring to a single rate heavier, that alone changes many factors( and will be off either on the bottom of the fork or supple action at the top. IT's just going to require testing, but I have no problemo trying 15 weight in the vfr on stock spring, might even try myself in the future.

But going to stiffer spring, if you also go to a heavier oil to slow rebound, then you also get heavier compression, which can create a different can of worms.

[npat]

But going to stiffer spring, if you also go to a heavier oil to slow rebound, then you also get heavier compression, which can create a different can of worms.

I understand this. That's why I'm asking for some empirical advice (if someone has done something similar).

I know (do I?) that for my weight I need 0.95kg/mm fork springs (maybe even 1.0kg/mm). Ideally, I should also revalve my forks for the new springs. But if I forego, or postpone, this last step (revalving)---for reasons having to do with cost and, mostly, timing---would the stiffer springs plus heavier oil, be a reasonable compromise? If not, what would be?

"Nothing" is, of course, a valid answer, in which case I should postpone replacing the springs (and also possibly the shock) until such time as I could also do the revalving.

[spud786]

But going to stiffer spring, if you also go to a heavier oil to slow rebound, then you also get heavier compression, which can create a different can of worms.

I understand this. That's why I'm asking for some empirical advice (if someone has done something similar).

I know (do I?) that for my weight I need 0.95kg/mm fork springs (maybe even 1.0kg/mm). Ideally, I should also revalve my forks for the new springs. But if I forego, or postpone, this last step (revalving)---for reasons having to do with cost and, mostly, timing---would the stiffer springs plus heavier oil, be a reasonable compromise? If not, what would be?

"Nothing" is, of course, a valid answer, in which case I should postpone replacing the springs (and also possibly the shock) until such time as I could also do the revalving.

Well, lets take the time I had those CR forks just perfect, except for uphill Big whoops section, I spent about $300 for race tech to do gold valves and a revalve, they redid it twice cause too soft the first time and really screwed up the second time, with to0 stiff intial and too soft on the bottom, I had to run intial action too stiff to have over all workability. Over all race tech was a waste of money for me.

But most that have installed 1.0 fork springs, have found them to very stiff and uncomfy on the street

[npat]

Well, lets take the time I had those CR forks just perfect, except for uphill Big whoops section, I spent about $300 for race tech to do gold valves and a revalve, they redid it twice cause too soft the first time and really screwed up the second time, with to0 stiff intial and too soft on the bottom, I had to run intial action too stiff to have over workability. Over all race tech was a waste of money for me.

But most that have installed 1.0 fork springs, have found them to very stiff and uncomfy on the street

Ok... So what do you think would be reasonable spring rates (both front and rear) for my weight (approx 220lb)? I got the 0.95/19.3 or 1.0/20.3 figures from here (which seems to more-or-less agree with the fork-spring rate suggestions from racetech).

[scmiata1990]

Hello,

I have .95 Ractech springs, valves, oil, (sorry don't remember weight they used.) On the back I have an Ohlin shock with a 19.3 spring, I am 170 pounds and ride

part of the time with loaded factory panniers. I never ride with a passenger. Even without the panniers the suspension is not too stiff for me. I do ride aggressively.

I hope this helps.

[spud786]

If changing the spring rates, then you'd want the valving that goes with it, and would have to rely on who is setting it up and their recommend for spring rate. With forks and shock that offers full adjustments, you have more leeway for correcting errors in valving. I must have misunderstood and thought that you were just wanting to try 15 weight oil in your existing forks.

[npat]

I hope this helps.

A lot. It supports the conclusions in the "transformed wow!" thread (but seems to contradict spud786's statement about 1.0kg/mm springs being too stiff). So, putting 0.95/19.3 springs will be erring on the soft side (rather than on the stiff) for my hefty 220lbs.

My only worry is that if I change the fork springs without revalving, then should I also put heavier oil or a lighter one? (Or should I not change the fork springs at all without revalving?)

[npat]

If changing the spring rates, then you'd want the valving that goes with it, and would have to rely on who is setting it up and their recommend for spring rate. With forks and shock that offers full adjustments, you have more leeway for correcting errors in valving. I must have misunderstood and thought that you were just wanting to try 15 weight oil in your existing forks.

No, I would also like to change my fork springs (and shock spring as well, together with an ohlins shock)... So, you are saying that if I'm not ready to revalve the forks, then I should definitely *not* replace my springs (changing oil---lighter or heavier---will not be a reasonable compromise until such time as I'm ready to do the revalving).

[spud786]

You can proceed that way, but I think a Heavier fork spring in addition to heavier oil, would be too much for stock compression valving. Considering I havent ran the Point .95 or the 1.0 with stock valving, the reaction of that set up is an unknown to me.

[zRoYz]

There are so many variables it is very hard to advise what spring rate you should use because everybody is different for the feel they want, just upgrading the vfr springs from the standard progressive to linear makes allot of difference. On the fork oil subject the problem with just adding weight to oil is you slow down the response of your forks & I'm not talking about rebound but overall response the lighter weight oil you use the better response which is why valving is the key. Now because your looking at doing springs & oil your not taking much extra for a suspension tech to adjust your standard shim stacks to suit, in fact my personal opinion is adjusting the standard valving shim stacks works better than replacing complete valving with racetech or the like on the vfr. I have used racetech valving & hated it on my 6th gen went back to standard with adjusted shim stacks & was 100% better for what I like, but again everybody is different. The problem with racetech valving etc is it is based on sportsbike data which load the front end far more than the vfr does, this is also the case when using recommended spring rate charts there all sportsbike data.

Due to your explanation of bumpy roads etc, I'm sure what I like would be very close to what you would want because I prefer a plush ride (plush doesn't mean bouncy) so tend to not go for the heavier spring rate but rely on a good valving setup to do allot of the work. If you don't have a local suspension tech it can be difficult to have things fine tuned if spring rates aren't spot on first go which most think with road bikes when you go to a suspension tech it is perfect first go, well it's not it's just you feel it is better than the suspension you had before & the placebo effect you spent money on your suspension so it must be better. If you have a local guy they will change out springs for no cost (well they do in AUS) until it's correct for what you want.

With forks if money is that tight I would tend to jump up the spring rate to what you need which would be 0.9 - 0.95 at a guess & use quality 7.5W race fork oil (there is a difference from standard & it does work allot better) but drop the air gap to 85-90mm which tends to have same effect as going heavier oil but helps keep response (standard vtec fork oil 8W). If you want to increase oil weight then use 10W at standard air gap, but bottom line you can fine tune just with oil level a little more or a little less but rule of thumb is don't go further than 15mm either way.

7.5W in race is a standard of the shelf you can't buy 8W in race in AUS but might be different else where, I don't believe in mixing different weight oil to gain the weight your after, oil I use is Motul Racing Line.

[npat]

There are so many variables it is very hard to advise what spring rate you should use because everybody is different for the feel they want, just upgrading the vfr springs from the standard progressive to linear makes allot of difference. On the fork oil subject the problem with just adding weight to oil is you slow down the response of your forks & I'm not talking about rebound but overall response the lighter weight oil you use the better response which is why valving is the key. Now because your looking at doing springs & oil your not taking much extra for a suspension tech to adjust your standard shim stacks to suit, in fact my personal opinion is adjusting the standard valving shim stacks works better than replacing complete valving with racetech or the like on the vfr. I have used racetech valving & hated it on my 6th gen went back to standard with adjusted shim stacks & was 100% better for what I like, but again everybody is different. The problem with racetech valving etc is it is based on sportsbike data which load the front end far more than the vfr does, this is also the case when using recommended spring rate charts there all sportsbike data.

Due to your explanation of bumpy roads etc, I'm sure what I like would be very close to what you would want because I prefer a plush ride (plush doesn't mean bouncy) so tend to not go for the heavier spring rate but rely on a good valving setup to do allot of the work. If you don't have a local suspension tech it can be difficult to have things fine tuned if spring rates aren't spot on first go which most think with road bikes when you go to a suspension tech it is perfect first go, well it's not it's just you feel it is better than the suspension you had before & the placebo effect you spent money on your suspension so it must be better. If you have a local guy they will change out springs for no cost (well they do in AUS) until it's correct for what you want.

With forks if money is that tight I would tend to jump up the spring rate to what you need which would be 0.9 - 0.95 at a guess & use quality 7.5W race fork oil (there is a difference from standard & it does work allot better) but drop the air gap to 85-90mm which tends to have same effect as going heavier oil but helps keep response (standard vtec fork oil 8W). If you want to increase oil weight then use 10W at standard air gap, but bottom line you can fine tune just with oil level a little more or a little less but rule of thumb is don't go further than 15mm either way.

7.5W in race is a standard of the shelf you can't buy 8W in race in AUS but might be different else where, I don't believe in mixing different weight oil to gain the weight your after, oil I use is Motul Racing Line.

Thanks a lot! This is very helpful.

Regarding revalving using the stock valves, do you have any suggestions as to what will work with a 0.95 spring? I'm nor seeking race-level sharpness and perfection, just decent traction with not too stiff a feel.

[zRoYz]

Unfortunately I have allot of knowledge about suspension from feel & how to setup, but as far as knowing the exact modification to the shim stacks to achieve different operating scenarios I know nothing & leave that to an expert that has the knowledge I don't, from working with suspension continually as there profession. Due to the vfr not having any external adjustment available you need to know what your doing 100% with shim stack changes or your going to be pulling your forks apart allot experimenting, this is why when you find a ball park set up & want a little more fine tuning a layman can play with oil level a little to achieve that.

[npat]

Unfortunately I have allot of knowledge about suspension from feel & how to setup, but as far as knowing the exact modification to the shim stacks to achieve different operating scenarios I know nothing & leave that to an expert that has the knowledge I don't, from working with suspension continually as there profession. Due to the vfr not having any external adjustment available you need to know what your doing 100% with shim stack changes or your going to be pulling your forks apart allot experimenting, this is why when you find a ball park set up & want a little more fine tuning a layman can play with oil level a little to achieve that.

I WILL go to a professional, I'm not suggesting I'll to do the work myself. I'm just wondering what I should expect. I mean, is there some standard, reliable way of compensating for spring-rate and oil-weight changes with revalving (that every suspension professional knows, and can perform with confidence), or is this a "black art" kind of thing, and the specialist has to be familiar with the specific bike, and go "trial and error"? Again, I'm not talking about ultimate precission, but a reasonably decent setup.

[zRoYz]

That is a very valid point & one could answer with maybe some every day life logic. We all know in life in every profession you have those that excel, those that are average & those you probably should avoid. My personal experience with suspension techs is the same so you really need to do some research on who you use, but this can be difficult because you can find someone with a particular bike that raves about the person who has done there work & then ask someone with a different model bike who isn't impressed. I find the biggest problem with motorbike suspension is all the R&D data is sportbike orientated & what works on a sportbike wont necessarily be the correct set up for a sports tourer or the like.

I went through 3 suspension techs before I found one that could set up the suspension on my bikes the way I wanted not the way they think I want as there is a very big difference. I hinted earlier about how people spend money on there suspension as far as drop parts or bike off, try to explain how they ride, give there weight & then in a few days pick it up & that's it. But is what has been done the best possible out come when for example on mostly smooth tracks race bikes suspension is constantly being changed to conditions, yet your road bike which has to contend with so many more variables is perfect with a one off adjustment. This is were I think what ever bike you have you need to find a suspension tech who has modified your model bike before with good results & with a guarantee if your not happy will rework your suspension no extra charge to get it right within reason.

For example the person I use does his own R&D to the point he try's something tells you to ride it & come back with feed back & if feed back isn't great makes other changes, I have been his test rider for a number of experiments but mainly for the vfr. The reason he has used me is I like a very particular set up as I'm a front end rider but I don't like a stiff set up I like a very plush set up which isn't an easy way to get suspension to feel when your a corner monkey that likes to ride fast. But that type of set up is perfect for the road & the vfr which really doesn't load a front end much at all, the vfr tends to load the rear allot more due to the very neutral geometry & the reason sportsbike data just doesn't cut the mustard when selecting spring rates & valving on the vfr. This is why I tend to like the standard valving with just a shim stack adjustment because showa designed the valving to work for how the vfr loads the front, but you need to change the shim stacks which is fine tuning when you change out the standard spring rate which it was designed to work with. I'm not saying that different aftermarket valving can't be better, but for the cost I don't feel there is that much improvement compared to just having the standard valving shim stacks adjusted to suit your needs. My vtec (frankenviffer) in it's present configuration has CBR1000RR FGRT Ohlins forks which most would think bolt the Ohlins stuff on my bike because it is meant to be so good which again is the placebo effect, well they have more internal adjustments you can do than a standard fork & to get them set up correctly I have had them internally adjusted 3 times to suit me & the vfr.

So really it is a matter of asking questions & asking the tech you might use will they back up there adjustments with further adjustments if you don't like the feel from the first attempt & it is always a good move to find someone who has made adjustments to your model bike before.

[npat]

That is a very valid point & one could answer with maybe some every day life logic.

...

So really it is a matter of asking questions & asking the tech you might use will they back up there adjustments with further adjustments if you don't like the feel from the first attempt & it is always a good move to find someone who has made adjustments to your model bike before.

All very reasonable! The problem is that most suspension guys around here (there are not so many of them, to start with) have NO real experience with bikes like the VFR. They mostly deal with off-road stuff (mx, enduro or whatever) and some basically track-oriented sport-bike work. The VFR is not terribly popular here, and most of the guys who own it are not the type of guys who are likely to go looking for suspension mods; neither am I, really! I much prefer spending money on gasoline, rather than on mods and upgrades. If I find a solution that, say, 90% works (whatever this may mean) I will be happy to leave it at that, even if I know that with a lot of tweaking I could go the extra 10% of the way... That's why I'm looking for mostly "tried", and "safe" options, and generally set my expectations level quite low; that is:

- I want it to be safe

- I want it to be *obviously* better than stock

- I want my comfort zone to extend to paces A LITTLE faster than with the stock suspension setup

- I am ready to sacrifice A LITTLE ride comfort to get these in exchange (but not TOO much).

Are those too much to ask for?

[spud786]

There's a company called Hyperpro, they sell progressive rate upgraded springs, Stock springs are progressive too, or at the very least you could call them dual rate.

What gets me, is Hyper pro's springs, call for 20 weight oil on the vfr, that spring would have to be very similar to stock or lighter to even have a chance to work with 20 weight oil. I called and talked to them once , they are fairly tight lipped and dont want to devulge information. But That really springs an interest in trying higher weight oil on the vfr.

[npat]

Does anyone know what is the stock fork-springs rate for the VTEC? I thought it was 0.75kg/mm, or is it 0.85?

The rear is 15.3, right?