RT Weight distribution

[dangme55]

Hi all -

I have googled to death and searched the forums. I cannot find a single post / article on the front/rear weight distribution of any Spyder.

Has anyone put their Spyder (preferably RT-S) on scales to get weight / front to rear numbers at curb weight configuration?

Any know the CG location at curb weight?

thanks in advance!

 

[Dan McNally]

Try this: http://www.operatorsguides.brp.com/...s/OwnersManuals_SSA/attach/06/2013/2718EN.pdf

 

[dangme55]

Thanks - but not the whole story

Try this: http://www.operatorsguides.brp.com/...s/OwnersManuals_SSA/attach/06/2013/2718EN.pdf

Thanks - I looked but it only has as far as I can see the dry weight which is okay as far as it goes but doesn't give me the info I want. Unless someone has done it already I guess I will have to get the scales out and get the data that way. I love the Spyder but BRP is so lacking in real technical information about it. A good deal of info is really skimpy - like lamps #'s etc

If I have to weigh the bike I will post the numbers so they will be available to everyone. I can probably calculate the fore aft point of the cg but height will be problematic.

 

[liketoride2]

Sorry, I've never weighted my Spyder, either front - rear or its total weight. It is quite obvious there is a substantial front weight bias.

Just curious, why is this of interest to you? It seems from your post that it's quite important. I suspect most of us take the attitude it is what it is and changing it would be very difficult. I've often wished there was less front end weight bias but as a practical matter can't think of any reasonable way of changing it.

Mike
Idaho
www.rtwrider.net

 

[ulflyer]

Jim is gonna put wings on it so it will fly and has to get the proper CG in order to balance it............:joke:

 

[Bob Denman]

It's probably just me being cranky...
But since you're not able to change it by any appreciable amount; why worry about it?:dontknow:
However; if you're using the info to set the bike on a single axle trailer... :thumbup:

 

[3 Wheel Addict]

I would think if your going to load it down try to keep most of the weight to the rear. The tire on the back holds a great deal of weight capacity and the front ground clearance is already minimal. If your going to haul a large amount of gear get the BRP (or similar) trailer.

 

[Bob Denman]

:agree: Grab it by the belly, and both ends come along for the irde! :thumbup:

 

[dangme55]

Weight distribution It is important - for suspension tuning

Sorry, I've never weighted my Spyder, either front - rear or its total weight. It is quite obvious there is a substantial front weight bias.

Just curious, why is this of interest to you? It seems from your post that it's quite important. I suspect most of us take the attitude it is what it is and changing it would be very difficult. I've often wished there was less front end weight bias but as a practical matter can't think of any reasonable way of changing it.

Mike
Idaho
www.rtwrider.net

Mike -

I love people who are curious - I am very curious - good thing I am not a cat. LOL

It is true that you cannot change the F/R very easily - I presume it has a front bias. To make it more neutral you could add more weight to the rear but that is not a good trade off To do that you would need the CG to make it most effective. But that is a digression - changing weight distribution is not my goal (at least for now)

There is a good bit of information on the forum(s) about shocks/ preload etc. A lot of it while being true for a single individual's riding preferences it is not, as far as set up / tuning a suspension, useable to get a desired goal. There are a lot of myths about different suspension settings most notably pre-load.

I am working on the front suspension of my 2013 RTS. I want it to be a little firmer but still 'cruising' comfortable. So far I have two ideas - I ordered 2014 shocks (another previous post in this forum) and I am waiting for them to come in. They are supposedly a bit stiffer and have better damping than the 2013.

My other option is to 'engineer' a 'custom' spring shock combination from readily available parts. In order to do that you have to know the corner weight of the wheels - hence I wondered if that info was available and it seems no one know. F/R weight distribution is readily available for most cars. Apparently not for the :spyder2: :sour:
I guess I will have to bring some beer to a friend that has race scales.:cheers:

Once you know the F/R and corner weight you make a number of suspension measurements. Armed with those numbers there are a lot of calculators on the net that will crunch the numbers.

If you are really curious you can look on Amazon. I have had this book in my reference library for a long time - it is written so a layman can use it.

Chassis Engineering: Chassis Design, Building & Tuning for High Performance Handling by Herb Adams


Right now I am on the idea of using QA1 shocks and 250# springs. I am pretty sure that this will fit but I haven't tried it yet so no part numbers for publication yet. If I go this route I will have a front suspension with shocks that have 18 adjustments for both compression and rebound settings. So I will be able to set the front end up with a 'click of the knobs' from soft to firm depending on whether I want to cruise or ride a bit more spirited.

This combination will also be pre-load adjustable unlike the stock shocks. (Like the aftermarket ones)

The cost should come in somewhere around $400-425. (2 shocks - 2 new springs)

Shocks are just one of the mod projects that I already have the parts for and are in the queue. The rest that are in queue are:
Spyderpops front skid plate
Arkrapovic exhaust
55 W HID lights ( 4500 lm)
24 watt led's for fogs (4300K 1500 lm)

mods completed:
bores1 gps holder
Ultimate seat
Bajaron sway bar
rivco dual flag mount
hopnel triple pouch for dash
'Spyder' rear hub overlays
carbon fiber skid/scratch pads for front of saddle bags
ipod mount for rear trunk

Well I guess I better head out to the shop/Spyder and see if I can shorten that queue.

 

[dangme55]

With enough power LOL

Jim is gonna put wings on it so it will fly and has to get the proper CG in order to balance it............:joke:

I flew F-4 Phantoms which proved the hypothesis that with enough power you can make anything fly. hyea:

not sure if I can get a GE J-79-10 mounted on the Spyder. Though it might be worth a try.

 

[Pappazippy]

Front vs rear weight is important for people building a custom trailer for towing a Spyder. Most car manufacturers publish the weight ratios for their cars. It has nothing to do about what is loaded on the bike it is how weight distribution affects the loading and towing. Most cars have a ratio of 60/40 front to back respectfully. The most weight being in the front due to the engine and transmission mass. I understand what the OP is asking and pretty sure why. If I had a good set of scales I would weigh the spyder just so I knew. No particular reasons other than I used to weigh airplanes to calculate the CG. On a trailer, the mass distribution is good to know for proper positioning for the best towing stability. The CG should be centered over the trailer's axle or slightly forward for the trailer to be stable. I think it is a good question but it appears it may be hard to answer without getting expensive transducers to actually read the weight distribution. I can think of other reasons for front vs rear weight distribution like doing custom frame modification. Too little weight to the rear it will roll like a ball on a hard stop. Good luck in getting the information you need. I would be interested in what the OP finds out.

 

[ulflyer]

I flew F-4 Phantoms which proved the hypothesis that with enough power you can make anything fly. hyea:

not sure if I can get a GE J-79-10 mounted on the Spyder. Though it might be worth a try.

I just had a feeling that you might be/had been an airplane jockey. Having built and flown several ultralights I'm generally familiar with CG's. Won''t go into what happened when, on my first one, I hitched the ailerons up backwards! Now, that test flight was some kind of ride.........:yikes:

 

[spacetiger]

Mike -

I love people who are curious - I am very curious - good thing I am not a cat. LOL

It is true that you cannot change the F/R very easily - I presume it has a front bias. To make it more neutral you could add more weight to the rear but that is not a good trade off To do that you would need the CG to make it most effective. But that is a digression - changing weight distribution is not my goal (at least for now)

There is a good bit of information on the forum(s) about shocks/ preload etc. A lot of it while being true for a single individual's riding preferences it is not, as far as set up / tuning a suspension, useable to get a desired goal. There are a lot of myths about different suspension settings most notably pre-load.

I am working on the front suspension of my 2013 RTS. I want it to be a little firmer but still 'cruising' comfortable. So far I have two ideas - I ordered 2014 shocks (another previous post in this forum) and I am waiting for them to come in. They are supposedly a bit stiffer and have better damping than the 2013.

My other option is to 'engineer' a 'custom' spring shock combination from readily available parts. In order to do that you have to know the corner weight of the wheels - hence I wondered if that info was available and it seems no one know. F/R weight distribution is readily available for most cars. Apparently not for the :spyder2: :sour:
I guess I will have to bring some beer to a friend that has race scales.:cheers:

Once you know the F/R and corner weight you make a number of suspension measurements. Armed with those numbers there are a lot of calculators on the net that will crunch the numbers.

If you are really curious you can look on Amazon. I have had this book in my reference library for a long time - it is written so a layman can use it.

Chassis Engineering: Chassis Design, Building & Tuning for High Performance Handling by Herb Adams


Right now I am on the idea of using QA1 shocks and 250# springs. I am pretty sure that this will fit but I haven't tried it yet so no part numbers for publication yet. If I go this route I will have a front suspension with shocks that have 18 adjustments for both compression and rebound settings. So I will be able to set the front end up with a 'click of the knobs' from soft to firm depending on whether I want to cruise or ride a bit more spirited.

This combination will also be pre-load adjustable unlike the stock shocks. (Like the aftermarket ones)

The cost should come in somewhere around $400-425. (2 shocks - 2 new springs)

Shocks are just one of the mod projects that I already have the parts for and are in the queue. The rest that are in queue are:
Spyderpops front skid plate
Arkrapovic exhaust
55 W HID lights ( 4500 lm)
24 watt led's for fogs (4300K 1500 lm)

mods completed:
bores1 gps holder
Ultimate seat
Bajaron sway bar
rivco dual flag mount
hopnel triple pouch for dash
'Spyder' rear hub overlays
carbon fiber skid/scratch pads for front of saddle bags
ipod mount for rear trunk

Well I guess I better head out to the shop/Spyder and see if I can shorten that queue.

Jim,

I thought that is where you were going with this question(s).

My only suggestion at this point is to remove one of the front shock/spring assemblies to determine the spring rate. I always do this before modifying the suspension so I know what my starting point is. You can do this a few ways; here is how I did it. I used some gym equipment I have at home; a machine that you load up weights to work your shoulders and chest. I place the fork or rear shock under the weight stack. From there I measure the extended length of the fork/shock, then add weight and measure [compressed] length. As you add more and more weight measuring the length every time, you can graph out the length vs weight and use EXCEL to plot out the data points. You can add a linear trendline and chose the option to display the equation of the trendline. This will smooth out the slight inaccuracies in the collected data. The slope of the line is the spring rate (#/in). Once you have this info, you can compare it to other aftermarket shocks and see how much stiffer the new shock is over the oem.

Some side thoughts:
1. We have a swaybar, so this must be accounted for as it adds to the effective spring rate when the bike is is in a turn. When the frontend is under a same rate load (like hitting a speed bump straight on), the sway bar does not effect the suspension.
2. I have always used linear rate springs when modifying motorcycle suspensions, but I think the RT might benefit by going to progressive springs. I would go with a spring that has a stiffer rate than stock but transitions to a rate equal to the aftermarket shock springs (at a minimum). This would give you a softer ride for the small bumps but carry stiffer rates for when you are aggressive in the turns. If you go this way, make sure you have a stiffer sway bar.
3. when you start looking at the rear, you can remove the rear shock assembly and measure its spring rate too. It may have a linear rate but you have to verify if you have a linkage setup that makes the rate a compound rate (effectively making it a progressive rate). You plot the front (make sure you use front spring x 2) and rear spring data so you have a front/rear oem data capture. As you consider changes, you can quantify the changes.
4. Shock damping is another matter. I think you can get good performance by just changing one end (front). I think that is the one advantage of the aftermarket shocks - control on the rebound and compression damping. But, they are REALLY expensive. I think if you had this control, you could do a nice job dialing in the suspension.

I can post a link to how I measured spring rates but you'll have to sign up to the site to gain access. Let me know if you want me to do this.

Keep us posted on how you progress.

Jerry

 

[Bob Denman]

Jim,
This all sounds about four steps beyond "ambitious"... Good Luck, and please keep us in the loop! :2thumbs:

 

[Frank G]

Re-Inventing the wheel

1) The people at Elka have already done extensive testing with all types of springs. Some of this info is on there web site.
2) After Elka's share of the market, there is not much left.

3) "The Weigh in" Purchase 3 bathroom scales from Walmart. Unwrap them carefully, weigh the Spyder, return them, or better yet give them to the in laws for Christmas.:yikes:

These are just my thoughts, no disrespect of what you are doing. Without challenging the science there would be no advancements.

 

[Yfactor]

I flew F-4 Phantoms which proved the hypothesis that with enough power you can make anything fly. hyea:

not sure if I can get a GE J-79-10 mounted on the Spyder. Though it might be worth a try.

:2thumbs: Jet power!:b2b:

 

[dangme55]

Good stuff to know

Jim,

I thought that is where you were going with this question(s).

My only suggestion at this point is to remove one of the front shock/spring assemblies to determine the spring rate. I always do this before modifying the suspension so I know what my starting point is. You can do this a few ways; here is how I did it. I used some gym equipment I have at home; a machine that you load up weights to work your shoulders and chest. I place the fork or rear shock under the weight stack. From there I measure the extended length of the fork/shock, then add weight and measure [compressed] length. As you add more and more weight measuring the length every time, you can graph out the length vs weight and use EXCEL to plot out the data points. You can add a linear trendline and chose the option to display the equation of the trendline. This will smooth out the slight inaccuracies in the collected data. The slope of the line is the spring rate (#/in). Once you have this info, you can compare it to other aftermarket shocks and see how much stiffer the new shock is over the oem.

Some side thoughts:
1. We have a swaybar, so this must be accounted for as it adds to the effective spring rate when the bike is is in a turn. When the frontend is under a same rate load (like hitting a speed bump straight on), the sway bar does not effect the suspension.
2. I have always used linear rate springs when modifying motorcycle suspensions, but I think the RT might benefit by going to progressive springs. I would go with a spring that has a stiffer rate than stock but transitions to a rate equal to the aftermarket shock springs (at a minimum). This would give you a softer ride for the small bumps but carry stiffer rates for when you are aggressive in the turns. If you go this way, make sure you have a stiffer sway bar.
3. when you start looking at the rear, you can remove the rear shock assembly and measure its spring rate too. It may have a linear rate but you have to verify if you have a linkage setup that makes the rate a compound rate (effectively making it a progressive rate). You plot the front (make sure you use front spring x 2) and rear spring data so you have a front/rear oem data capture. As you consider changes, you can quantify the changes.
4. Shock damping is another matter. I think you can get good performance by just changing one end (front). I think that is the one advantage of the aftermarket shocks - control on the rebound and compression damping. But, they are REALLY expensive. I think if you had this control, you could do a nice job dialing in the suspension.

I can post a link to how I measured spring rates but you'll have to sign up to the site to gain access. Let me know if you want me to do this.

Keep us posted on how you progress.

Jerry

Thanks Jerry - at least I have someone else who thinks I am marginally sane. LOL

Elka tested the springs and there is a post in their development thread that says they test at around 210#. I did the calculations based on spring measurements and got around 350# as the theoretical rate. I have no doubt Elka knows how to do such things. Hence I believed there measurements and still I upped the spring rate just a tad.

I had not thought much about progressives - I will have to look-see if there are any that are 250/370. From reading posts I think #350+/- is generally what Elka uses.

May take a look at the progressive option.

Leaving the rear end alone for now. RT-S has the adjustable preload/ride and I think that mod' there are a bit too ambitious for right now. I don't think I am changing the front rate enough to upset any 'balance' between front and rear.

People routinely do just the front with Elka and don't seem to have a problem with that 'big' 350+ change in rate.

The total order (so far) is $490 (pretty frugal compared to aftermarket, but then there is the joke about knowing where to hit the machine with the hammer. LOL) I hope I made the right measurements.

 

[dangme55]

Discussion if the maker of advancement

1) The people at Elka have already done extensive testing with all types of springs. Some of this info is on there web site.
2) After Elka's share of the market, there is not much left.

3) "The Weigh in" Purchase 3 bathroom scales from Walmart. Unwrap them carefully, weigh the Spyder, return them, or better yet give them to the in laws for Christmas.:yikes:

These are just my thoughts, no disrespect of what you are doing. Without challenging the science there would be no advancements.

Frank -

No offense taken. I enjoy give and take on issues. Always learn something or see something a bit different before it bites you. :gaah:

I have a lot of respect for Elka. they have lots of experience and expensive equipment which makes their product worth the price to someone who wants a bolt-on turnkey solution.

I do not see any really technical information on the Elka web site. Perhaps I am not looking in the right place on their web site.

there is very little tech information there that I can find- no spring rates, no compression/rebound curves, etc. At least none that I can find. I read through Elka's development thread and they said they were going to post dyno info etc. Again I do not see it in any follow on post. So most of what I see there is marketing level information not technical. Go to any shock manufacturer(Koni, Bilstein, QA1) and you will get tons of information, valving, curves, etc. Maybe too much information.


If you have something different from the Elka web site please point me there. The price for 1+r's and above is more than I care to pay for a 'black box' suspension solution. BRP is not very forthcoming with technical information either. Maybe it is a Quebec thing.

 

[dangme55]

Been there done that

I just had a feeling that you might be/had been an airplane jockey. Having built and flown several ultralights I'm generally familiar with CG's. Won''t go into what happened when, on my first one, I hitched the ailerons up backwards! Now, that test flight was some kind of ride.........:yikes:

i used to fly check flights after maintenance. had an F-4 set up that way by hydraulic team. missed it on preflight somehow. you know 'stick right' left aileron up (or is it down lol) yada yada

I agree it is a handful to do everything backwards :yikes::yikes:

If I could have turned around in the seat and flown by mirror it would have all looked right LOL

 

[spyder stryder]

rt weight distribution

Mike -

I love people who are curious - I am very curious - good thing I am not a cat. LOL

It is true that you cannot change the F/R very easily - I presume it has a front bias. To make it more neutral you could add more weight to the rear but that is not a good trade off To do that you would need the CG to make it most effective. But that is a digression - changing weight distribution is not my goal (at least for now)

There is a good bit of information on the forum(s) about shocks/ preload etc. A lot of it while being true for a single individual's riding preferences it is not, as far as set up / tuning a suspension, useable to get a desired goal. There are a lot of myths about different suspension settings most notably pre-load.

I am working on the front suspension of my 2013 RTS. I want it to be a little firmer but still 'cruising' comfortable. So far I have two ideas - I ordered 2014 shocks (another previous post in this forum) and I am waiting for them to come in. They are supposedly a bit stiffer and have better damping than the 2013.

My other option is to 'engineer' a 'custom' spring shock combination from readily available parts. In order to do that you have to know the corner weight of the wheels - hence I wondered if that info was available and it seems no one know. F/R weight distribution is readily available for most cars. Apparently not for the :spyder2: :sour:
I guess I will have to bring some beer to a friend that has race scales.:cheers:

Once you know the F/R and corner weight you make a number of suspension measurements. Armed with those numbers there are a lot of calculators on the net that will crunch the numbers.

If you are really curious you can look on Amazon. I have had this book in my reference library for a long time - it is written so a layman can use it.

Chassis Engineering: Chassis Design, Building & Tuning for High Performance Handling by Herb Adams


Right now I am on the idea of using QA1 shocks and 250# springs. I am pretty sure that this will fit but I haven't tried it yet so no part numbers for publication yet. If I go this route I will have a front suspension with shocks that have 18 adjustments for both compression and rebound settings. So I will be able to set the front end up with a 'click of the knobs' from soft to firm depending on whether I want to cruise or ride a bit more spirited.

This combination will also be pre-load adjustable unlike the stock shocks. (Like the aftermarket ones)

The cost should come in somewhere around $400-425. (2 shocks - 2 new springs)

Shocks are just one of the mod projects that I already have the parts for and are in the queue. The rest that are in queue are:
Spyderpops front skid plate
Arkrapovic exhaust
55 W HID lights ( 4500 lm)
24 watt led's for fogs (4300K 1500 lm)

mods completed:
bores1 gps holder
Ultimate seat
Bajaron sway bar
rivco dual flag mount
hopnel triple pouch for dash
'Spyder' rear hub overlays
carbon fiber skid/scratch pads for front of saddle bags
ipod mount for rear trunk

Well I guess I better head out to the shop/Spyder and see if I can shorten that queue.

Jim
If you know someone with a set of race car scales the guy might have a
spring rater If so check the rate on your springs then decide what you need
from there. On the shocks your friend may know someone at Pro Shocks in
Lawrenceville Ga that will dyno them for valving so as to make a better choice
on that even as they will have adj. compression & rebound. Just make sure
the new springs are a matched set on height & rate. Heck he might have some
springs in the 10"length you can test with.I know two guys that have the RTs that
use the Ron's bar with the elka 1+r one has the 250 springs & this setup works real
good,the other has the 300 springs & he complaines they are about to beat him to
death on anything on the rough side. I need one of these guys to pull a shock & lets
have it checked for valve rate as that is a well kept secret.

spyder strider
Dan