So I'm Fat And I Know Nothing About Bike Suspension....

[whiteboyslo]

me: 6'8" 320lbs w/o gear

bike: 04 VFR, about 24K miles, completely stock suspension. i have owned it since 14K miles.

so i've started to notice the front suspension sagging quite a bit during heavy braking. i know that the fluid is supposed to be changed periodically and is likely about due, and i have heard this is an optimum time to change springs in the forks to match my weight. even though i'm likely ridiculously overweight for whatever the stock suspension is designed for, i really haven't thought it to be all that bad. then again, the VFR is only my 2nd bike, and compared to the pogo stick suspension my sv650 had with me on it, anything would seem great!

so here's a laundry list of questions:

1) spring rate calculators on various websites suggest i need 1.1 kg/mm minimum. i'm not sure what the stock rate is, but i'm sure this is drastically higher. seeing how i have acclimated to the stock suspension, should i make the change?

2) if i do make a change and leave the rear suspension untouched, will this have a drastic effect on handling and ride characteristics?

3) is there anything else i should change while having the front forks rebuilt? should i change fluid weight? if so, to what?

if it matters, i would describe my riding style as mostly commuter with only the ever-so-occasional aggressive riding. and my aggressive riding would probably not be considered all that aggressive by most.

Mike

PS - i won't be doing the work myself. i have a buddy who is a mechanic at the local Honda / Kawasaki dealership who will likely do the work with me lending a hand.

[VFR4Lee]

Do both ends suspension together for best results.

Dropping 8 pounds is about = 1 horsepower iirc, so you might look there. :biggrin:

[Guest]

If your just going to commute, and really not ride hard I wouldnt put any $$ in the suspension..Id put the rear shock one click before full hard 3/4 preload from full, and have about 4 to 5 lines showing on the front forks..and see how that feels..now I "only" weigh 235ibs and 6'2" and am from what Im told Im a fairly hard rider ( lots of curve play) and I am going to upgrade my suspension soon..but at these settings I do probrably as good as I need to do on the street....play with the settings before you drop $$ on that suspension scince your not pushing it in the twists..IMO

[Ryanme17]

If your just going to commute, and really not ride hard I wouldnt put any $ in the suspension..Id put the rear shock one click before full hard 3/4 preload from full, and have about 4 to 5 lines showing on the front forks..and see how that feels..now I "only" weigh 235ibs and 6'2" and am from what Im told Im a fairly hard rider ( lots of curve play) and I am going to upgrade my suspension soon..but at these settings I do probrably as good as I need to do on the street....play with the settings before you drop $ on that suspension scince your not pushing it in the twists..IMO

Changing both at the same time would be best, yes. But just getting stiffer springs in front will probably help a lot, and doesn't cost too much.

[vfrcapn]

I'd recommend doing both ends at once. Setting one end up, the front say, with 1.1kg springs, might leave the back end sagging considerably compared to the new front. This could have negative affects on the handling. Work with the stock setup as best you can or do both at once. You can probably get a used shock fairly cheap that will take a heavier spring for not too much money, or maybe the stock shock can be resprung?

[VFR Capt.Bob]

If you like the bike and plan on keeping it then invest is springs that will support your weight. Do both at the same time and change the oil in the forks every season or two. Think about a shock upgrade for the future. Best money spent is on suspension for sure. Stock springs are for a person of about 175 lbs. Make that bike yours.

[whiteboyslo]

so if i change the back spring, am i OK with the stock shock for a little? my experience with playing with suspension on cages would say that i could be looking at a blown shock in the not-too-distant future by doing this.

and if i do change the rear spring, does anyone have any calculators to help me figure out what spring weight i would need?

will an aftermarket spring go on to the stock shock?

Mike

[V4 Rosso]

Definately upgrade both front and rear springs. Contact a reputable suspension specialist and they will be able to set you up with the right springs. The shop I got my suspension parts from at first thought I just wanted to buy a rear spring for the stock shock (3rd gen) and mentioned that Hyperpro springs were the closest fit. At 24K your shock may still be in a fairly good condition so you'll be OK with just upgrading the spring.

If your just going to commute, and really not ride hard I wouldnt put any $$ in the suspension..

I disagree. Dodging cagers in highway & city traffic calls for a good suspension setup. At 230lbs. and with stock boingers I got very close to bottoming out the forks when braking hard on smooth tarmac. At 320lbs you'll bottom out the forks even sooner and by doing so may loose the front end completely. The first thing I noticed after installing upgraded springs was how hard I could brake. I occasionally practice emergency braking and with the new springs I shortened my braking distance by a large margin :biggrin:

[TimC]

I'm a big guy, too, and bought a used CBR 900 shock last month to have rebuilt and modded for my higher weight. I'm planning to swap out the fork springs, too, with a set of RaceTechs I got from another VFRD member a couple years ago.

At 31k mi, my VFR is due for fork/shock work anyway. I noticed during a spirited ride a couple weekends ago that my bike was 'boinging' more than usual in some quick dips at higher speeds. Yep, definitely time to upgrade the suspenders.

I can't answer your specific questions, Mike, but up front you can probably go with stiffer springs or higher weight oil. I'm not sure I would do both.

Most riders say suspension mods are worth the money. Also, I would say if you mod one end you should go ahead and do them both, otherwise one will still be too soft and I think you'd still have some wallowing going on at the unmodded end.

[Guest]

Mike,

I would replace the springs on the front and rear at the same time. That way your suspension will be balanced. A new rear shock would be best but just putting a new spring on your current shock will defiantly help. I'm doing the same thing this summer. Then I'll either save up for a new rear shock or get lucky and find a used one and have it rebuilt.

Action

[Guest]

Definately upgrade both front and rear springs. Contact a reputable suspension specialist and they will be able to set you up with the right springs. The shop I got my suspension parts from at first thought I just wanted to buy a rear spring for the stock shock (3rd gen) and mentioned that Hyperpro springs were the closest fit. At 24K your shock may still be in a fairly good condition so you'll be OK with just upgrading the spring.

If your just going to commute, and really not ride hard I wouldnt put any $$ in the suspension..

I disagree. Dodging cagers in highway & city traffic calls for a good suspension setup. At 230lbs. and with stock boingers I got very close to bottoming out the forks when braking hard on smooth tarmac. At 320lbs you'll bottom out the forks even sooner and by doing so may loose the front end completely. The first thing I noticed after installing upgraded springs was how hard I could brake. I occasionally practice emergency braking and with the new springs I shortened my braking distance by a large margin :biggrin:

Now thats a good point there, braking would really be improved..and if your going to keep the bike..it would be worth it in the long run regardless if your not aggresive rider in the twists....I give no more advice :fing02:

[JamieDaugherty]

so if i change the back spring, am i OK with the stock shock for a little? my experience with playing with suspension on cages would say that i could be looking at a blown shock in the not-too-distant future by doing this.

and if i do change the rear spring, does anyone have any calculators to help me figure out what spring weight i would need?

will an aftermarket spring go on to the stock shock?

Mike

I'd suggest that you go with a 1.2kg/mm spring up front. These are custom order, but I can still get one for you at the same cost it just takes a couple of extra weeks.

I can also make a standard spring fit the shock with the use a collar. It takes special tools to remove and install the spring, so this is something you would have to send the shock to me to have done. I'd go with an 18.75kg/mm (1050lb/in) spring out back.

As has been mentioned, it's best to do both ends if you can. Even if you can only do one that's still better than stock. You won't 'go backwards' by changing the spring rate on just one, it's that you won't see the best results unless you address both the forks and shock.

You will not 'blow out' the stock shock by placing a higher rate spring on it. The stock shock is a decent unit and can hold up to a lot of punishment, you really won't be asking that much out of it anyway.

[DougFromIndy]

so if i change the back spring, am i OK with the stock shock for a little? my experience with playing with suspension on cages would say that i could be looking at a blown shock in the not-too-distant future by doing this.

and if i do change the rear spring, does anyone have any calculators to help me figure out what spring weight i would need?

will an aftermarket spring go on to the stock shock?

Mike

I'd suggest that you go with a 1.2kg/mm spring up front. These are custom order, but I can still get one for you at the same cost it just takes a couple of extra weeks.

I can also make a standard spring fit the shock with the use a collar. It takes special tools to remove and install the spring, so this is something you would have to send the shock to me to have done. I'd go with an 18.75kg/mm (1050lb/in) spring out back.

As has been mentioned, it's best to do both ends if you can. Even if you can only do one that's still better than stock. You won't 'go backwards' by changing the spring rate on just one, it's that you won't see the best results unless you address both the forks and shock.

You will not 'blow out' the stock shock by placing a higher rate spring on it. The stock shock is a decent unit and can hold up to a lot of punishment, you really won't be asking that much out of it anyway.

****My stock suspension seems AOK to me, I am 260#s....but I would like to have someone set sag on bike and maybe dial things in..seeing how you are closeby in Ft Wayne, maybe a few minutes help? I just never messed with it because it has worked for me. Staying with stock and saving for a multistrada S version in black with oem Ohlins, thats my planned mod, thanks Doug ***

[ECX585]

this shock stuff seems complicated..........think i'll put it off until next year.

[Veefer800Canuck]

Springs are one thing, and yes, they need to be suited for the rider's weight to get proper sag and chassis attitude, plus ride compliance without bottoming out over bumps, etc.

The second half of the equation is that the damping of the forks or shock, it's purpose is to control the motion of the spring.

Put in a stiffer spring, and you've fixed half the problem, and created another. The damping needs to be suited to the spring to have the correct effect.

Re-springing stock suspension will result in being underdamped as compared to the spring rate. You could compensate, to some extent, by oil weight in the fork, but unless you drill and tap the stock rear shock for a schraeder valve, and use heavier oil in there too, then the rear shock would then be underdamped with the stock oil and damping.

Really, using heavier oil is a bandaid for not enough damping. The PROPER way is to revalve the suspension for the spring rate and be done with it.

My two cents: Get a new aftermarket shock sprung specifically for your weight and be sure the company who sells it to you actually revalves it to suit.

Ship your forks to the same outfit and have them spring and revalve for you as req'd.

WHEN YOU GET YOUR BIKE BACK ON THE ROAD, YOU WILL THINK SOMEONE STOLE IT AND REPLACED IT WITH A BIKE TWICE AS GOOD!

Remember, when it comes to suspension, the best you've rode is the best you know.

Try asking around at Lindemann Enginerring, Traxxion Dynamics, AfterShocks, Race-Tech, Dan Kyle Racing, those are the ones that I can whip off the top of my head, but it's a start.

Be prepared to spend at least a grand to get results worth the money.

[Guest]

Definately upgrade both front and rear springs. Contact a reputable suspension specialist and they will be able to set you up with the right springs. The shop I got my suspension parts from at first thought I just wanted to buy a rear spring for the stock shock (3rd gen) and mentioned that Hyperpro springs were the closest fit. At 24K your shock may still be in a fairly good condition so you'll be OK with just upgrading the spring.

If your just going to commute, and really not ride hard I wouldnt put any $$ in the suspension..

I disagree. Dodging cagers in highway & city traffic calls for a good suspension setup. At 230lbs. and with stock boingers I got very close to bottoming out the forks when braking hard on smooth tarmac. At 320lbs you'll bottom out the forks even sooner and by doing so may loose the front end completely. The first thing I noticed after installing upgraded springs was how hard I could brake. I occasionally practice emergency braking and with the new springs I shortened my braking distance by a large margin :angry:

You do NOT want to bottom out the front forks. I had some squishy forks when I first got my bike I was going around a curve hit a good sized dip going around a curve, the front forks bottomed out, I hit the far side of the dip and the front end launched like a ramp into the air, which made the wheel turn to the side, not fun when I landed it I flipped over the bars and the bike flipped and landed on the tail, it was NOT fun.. Make sure your forks are in good shape.

[Guest]

so if i change the back spring, am i OK with the stock shock for a little? my experience with playing with suspension on cages would say that i could be looking at a blown shock in the not-too-distant future by doing this.

and if i do change the rear spring, does anyone have any calculators to help me figure out what spring weight i would need?

will an aftermarket spring go on to the stock shock?

Mike

I'd suggest that you go with a 1.2kg/mm spring up front. These are custom order, but I can still get one for you at the same cost it just takes a couple of extra weeks.

Contrare my friend. 1.2 springs for a ST1300 from Sonic will drop right in (I own an ST1300 also). I tried 1.2's for a while as that what Sonic's calculator told me that's what I needed. I wasn't using as much of the available fork travel as I thought I should be (I'm 265#) so I'm going down to the 1.1's. Best of my memory there is a couple of millimeters difference between the Sonic VFR springs and the Sonic ST1300 springs. Can easily be adjusted by cutting the spacers to a different length.

6'-8" and 320#. That's just one big dude. I certainly wouldn't call him overweight. Sounds like he was a defensive end on a college football team.

Remember, 6'-8" is doorway height. He has to duck to walk through most all doorways.

Oh yeah, rear spring. You're probably looking at a 1400# spring.

[Guest]

well I am 6'5" and about 335, so we are close, I ride the thing hard though (it is my toy bike not for commuting). my bike is a 98 fifth , I am running 1.05kg/mm springs on the front from sonic, RT compression and rebound valves g2Rs, the rebound valve is set 1 step less than their recommendations, and the compression 2 steps less, and the rear shock is a wilbers with hi/lo, and hyd preload, just call ted porter at teds beemer shop and tell him sport touring and your wt in gear and luggage wt. your shock will probably come in with a 22.9-23.9 kg/mm. spring. run 5 or 7.5 wt oil. You will be absolutely stunned at the difference! Then shim the rear mt up about 5mm and raise the tubes 5-8mm

Personally I do not know how you put that many miles on stock, the vfr is a total cow!!!!!!!!!!! if you are our size and the bike has stock suspension.

I am also running a regressive shim stack with about .005in preload on the stack.

this setup is just supple enough to ride in relative comfort but it is perfect for pushing it a bit (If you are a gap rat that means ~ 13"20" to 13'44" for the 11 mi) . Just a touch soft for a real hard track day.

[whiteboyslo]

So let's bring this back from the dead......

The bike is somewhere closer to 36K miles now. I've moved back to sunny SoCal, dropped down to a 'svelt' 300lbs, and am out on the bike darn near every weekend. Heck, I've even been to the track a couple of times and have more trackdays scheduled for the near future. All this extra seat time has added a lot to my confidence and my pace, but guess what I HAVEN'T done? That's right. Suspension is STILL bone stock.

I found a local guy who comes highly recommended, which is great because I have zero desire to do this work myself. He's definitely onboard with the idea of sourcing some OEM parts and modifying accordingly for my size, but now it's on both he and I to figure out what fits and what I need.

For the rear, it seems the best way to get the adjustability I want is a modified F4i shock, which he will then re-spring and modify accordingly. Is there a particular year I should look for, or will any F4i shock do?

For the front, he's a bit concerned that I will really need something with rebound dampening to compensate for the very heavy spring a big boy like me requires. If I wanted to swap out forks, what would work? Would it require de-linking the brakes? If so, how does one go about that?

Thanks in advance for any help! After 36K miles, I'm sure ANY work done to the bike will make it feel like new and I'm psyched to get it done!

Mike

[Baileyrock]

So let's bring this back from the dead......

For the rear, it seems the best way to get the adjustability I want is a modified F4i shock, which he will then re-spring and modify accordingly. Is there a particular year I should look for, or will any F4i shock do?

All F4-F4i shocks ARE THE SAME from 99-07 or 08 whenever they stopped making them and you'll need a top mount spacer aprox 15mm long.

For the front, he's a bit concerned that I will really need something with rebound dampening to compensate for the very heavy spring a big boy like me requires. If I wanted to swap out forks, what would work? Would it require de-linking the brakes? If so, how does one go about that?

If you don't care to de-link your guy can use F4i cartridges in the stock forks which will give you the Rebound adjustments your looking for. The stock rebound valve can be revalved and work pretty good, but I suggest you change Comp valves!

If you plan to de-link your options are endless!

Thanks in advance for any help! After 36K miles, I'm sure ANY work done to the bike will make it feel like new and I'm psyched to get it done!

Mike

Welcome back!

[Muff]

We are twin sons of a different mother

[TimC]

I modded my 2004's suspension last year and it made a big difference in the feel and performance of my bike.

I ended up buying a good used original 6th gen rear shock and having Jamie Daugherty rebuild it and swap out the original spring for a beefier one. At the same time my friend and I swapped out the rear shock, we swapped out the original fork springs for a set of RaceTech 1.0 springs, cleaned out the forks and replaced the fluid with a bit heavier weight oil.

The changes were noticeable immediately - my bike finally felt like a sportbike! I highly recommend modding suspension when necessary. I also heartily recommend Jamie's work.

[Monk]

I agree with TimC, I had Jamie mod my stock rear shock and he got me some Springs for my forks, and it rides great now..... 255 lbs.

[whiteboyslo]

Thanks for the help, guys!

BaileyRock, I've read up a bit on the F4i swap, and it looks pretty striaght-forward and the right way to go. But based on what I read, I need to somehow 'lengthen' the F4i shock. I saw the piece you used in your pictures. Is this something that can be purchased, or did you make it yourself?

And as to your suggestion of throwing in F4i cartridges to gain the adjustability I want, has this been done before? Is there a how-to anywhere?

Mike

[Baileyrock]

Thanks for the help, guys!

BaileyRock, I've read up a bit on the F4i swap, and it looks pretty striaght-forward and the right way to go. But based on what I read, I need to somehow 'lengthen' the F4i shock. I saw the piece you used in your pictures. Is this something that can be purchased, or did you make it yourself?

And as to your suggestion of throwing in F4i cartridges to gain the adjustability I want, has this been done before? Is there a how-to anywhere?

Mike

Mike, I made the spacer and many others have made their own also. It's not that hard.

Here is a How To from HS using F3 cartridges on a 5th gen(same size tubes, 41mm) it's the same basic job just using F4/F4i internals on the 6th gen instead, they both use 43mm tubes.

BR