Spring Shock

[Mapes]

I have been looking for a better set of shocks and springs and have not been able to find any that are worth mentioning. Does anyone have any recommendations on where to look or who to look at. If you could help I would be grateful thanks.
Mapes

[Mapes]

I have been looking for a better set of shocks and springs and have not been able to find any that are worth mentioning. Does anyone have any recommendations on where to look or who to look at. If you could help I would be grateful thanks.
Mapes

[pengulns2001]

helps to mention what you have and what you want better for all we know were telling you to get the same shock you already have http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Mapes]

well we have looked at Risse Racing company and then I heard that they weren't the best. Then I went and looked at Ohlins and really was unable to find anything about them. Right now the kind we have on our old car are off of an R6 which are extremely beefy in size and we are looking for something somewhat smaller. I hope this helps

[pengulns2001]

you could go with fox mountain bike shocks... they are extremely light and are a pretty good shock, ohlins makes a great damper but i personally think they have a bit to much "stiction"

[Marshall Grice]

I hear you recommending fox mtn bike shocks over ohlins car shocks based on performance? Did i misread something?

[pengulns2001]

i would use them... ill hopefully have something to backup my claim when we get our shock dyno back but from my experience im less than impressed with the ohlins, ive driven 4 cars and the ones with mountain bike shocks have been more responses

how much doesn an ohlins damper weigh? with a resavoiur (sp?) a mountain bike shock can weigh less than a pound

[kwancho]

Less than impressed? Too much stiction? Ohlins are pretty much the highest quality dampers on the market. Fox Racing dampers.... aren't.

[pengulns2001]

they are also made for much heavier applications... when i drive a car with ohlins that handles better than the cars iver driven with mountian bike shocks ill be impressed... or when we get our shock dyno back and i test the shocks back to back, maybe ill be impressed until then my experience is they arent worth the money, the time it takes to get them, or the weight

[mtg]

Are you talking about the ST44's?

I've heard complaints about low sensitivity of the compression damping circuit on those, but not about stiction. When you drove a car with Fox vs Ohlins, was it the same car? There can be HUGE amounts of stiction from the bearings in the suspension, or from the load paths of the whole system (ie monoshock with shuttlebar).

I'd be interested to see the dyno graph, once you get it.

[pengulns2001]

no they were different cars.. it was actually 2 with ohlins, 1 with fox and one with another mountain bike company that i cannot remember... i know the performance could have been due to a variety of things so im waiting on the shock dyno to get back the i will know for sure... the load path wasn't the problem as everything was on the same plane (or very close to) the bearings are another question...

[Marshall Grice]

Well i agree that there are many compromises to be made with shock selection, weight vs performance being one of them, but i don't see a fox bicycle shock out performing a purpose built racing shock in any aspect. Weight and packaging are different areas that bicycle shocks have an advantage. Re: driving different cars with different shocks and evaulating their performance. I'd say that the shocks rate fairly low on the overall vehicle performance scale when compared to other basic car setup items like tlltd(magic number). There certainly is a performance gain to be had from better shocks but only if you've got the rest of the car sorted as well.

[KU_Racing]

I would have to disagree with marshall.. I would say that after the engine and tires, the shocks that you use are the most important component you can select. damping on our cars is of extreme importance, more important than spring rate and roll rate on some cars. Also, I distinctly remember someone from Texas A&M saying that the performance they got from their shocks hugely outweighed the weight and size advantages of the mountain bike shocks. Maybe one of you guys (from A&M) can comment? also, I think that a true racing shock is much better in our application- if you analyze a mtn bike suspension vs. any car suspension, including an fsae car, it is obvious that the mtn bike shocks are designed with vastly different damping frequencies and rates in mind. Not to mention the fact that you cant buy a 4-way adjustable mountain bike shock.

[pengulns2001]

you have obviously never raced downhill mountain bikes... or looked into it.

speeds above 40mph arent un heard of and you can definatly buy 4 way adjustable mountain bike shocks, the weight per shock on a mountain bike is very similar to an FSAE car and with a good motion ratio you can have similar damping rates, the only downfall i see is the missmatch between shocks, which i havent personally seen but will test when our shock dyno gets back

[Marshall Grice]

Then i shall disagree with you disagreeing with me. http://fsae.com/groupee_common/emoticons/icon_smile.gif
I don't think that i said shock selection wasn't important. I said that they are a part of the suspension package. Focusing all of your attention( or none) on any one part is not going to be good for overall system performance. i agree that as a component shock quality is a large variable to control, partly because the range of quality is so large. However if you ignore other aspects of the suspension you can easily negate any advantage that the shocks can give you. Transient performance is a very important aspect of fsae type courses but that doesn't mean you can overcome poor steady state response with it.
There are some very fast cars with bicycle shocks, uta comes to mind. There are also some slow cars with car shocks, like us this yearhttp://fsae.com/groupee_common/emoticons/icon_wink.gif

[Marshall Grice]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">speeds above 40mph arent un heard of and you can definatly buy 4 way adjustable mountain bike shocks, the weight per shock on a mountain bike is very similar to an FSAE car and with a good motion ratio you can have similar damping rates, the only downfall i see is the missmatch between shocks, which i havent personally seen but will test when our shock dyno gets back </div></BLOCKQUOTE>

i don't think the actual speed of the vehicle has any bearing on a shocks performance. The heart of the problem is, like you said, the motion ratio. A desireable motion ratio for a bike(~3:1) is very different from fsae ~1:1.

I don't have personal experience with the fox shocks. I do have dyno plots for our old Risse's and our new Ohlins. Consistancy between shocks is considerably different.

[KU_Racing]

I dont see bike shock loads being terribly similar to racecar shock loads:

mtn bike: ~20 lbs
rider: 170 lbs
total: 190 lbs
weight distribution: ~50/50
rear shock load: 95 lbs

FSAE Car: ~500 lbs wet
driver: 170 lbs
total: 670 lbs
weight distribution: ~60/40
rear shock load: 198 lbs

marshall understood me i think- when i said damping rates/frequencies, i didnt mean pure vehicle speed; those are quite different things.

If I remember corrrectly, our old risse shocks were off by as much as 15% between the 4. Marshall, any idea how close your Ohlins are to each other? If they are already in use, how do you like them??

[Marshall Grice]

I do have an idea of how close...but i'm and work and don't have the plots infront of me. I'll have to update later. They are not in use yet unless you consider the hundreds of times i've compressed them and watched the extend while at my desk modeling parts. I swear they're going to be worn out before they even get on the car(well at least one of them). Like you said in your other post, if we can just finish those uprights....

[pengulns2001]

the weight on a mountain bike isnt 50-50... your front wheel is rarely on the ground if anything mountain bike shocks see more load.

were you at a different school last year? cause KU didnt test their shocks as far as i know (i was going there last year and a very active member of the team at that)

and i know what you mean by damping rates

[jdstuff]

Mapes,

We have used mountian bike shocks in the past, and frankly have never been impressed. Fox's never seemed to suit our appication well, and with Risse's we had tremendous quality problems (as others have already mentioned).

In back to back comparisons, Ohlins have made huge improvements to the handling of our cars. I would not hesitate to say that even though a bit more expensive, they're worth every penny. Also, don't believe agruments such as "they're designed for heavier cars." Of course you're not going to be able to take a stock TT44, bolt it onto the car, and expect it to work for your application. You have to design the shock. Spend the extra money, and buy the tools neccessary to valve them yourselves. If you're not comfortable doing this, have a reputable company build them for you. Chris Billings at The Shock Shop, located in Oregon (do a web search), is a pretty knowledgeable guy who is willing to work with you in designing the valving you will need. And Ohlins having "too much stiction...?" I'm sorry, but I just have to laugh at that one....then again, I'm just a drivetrain guy so what can I know?

As far as springs go, I would check out http://www.pohlsprings.com/. They will make you custom wound springs for about US$50, which is the cheapest I've found so far.

Hope that helps your search!

[Mapes]

Has anyone ever heard of Renton Coil Springs. I found them on the internet and they looked like pretty good quality. I think they make custom shocks. They also work with FSAE teams so I was just curious on the quality.
Mapes

[B Hise]

Jumping on the spring supplier bandwagon;

Kirk-Habict Spring Co.
410 686 9100
Baltimore, MD

They will wind any rate you want and do it fast. Pricing is also around $50 if I remember correctly. Mark is the owner is and partial to FSAE teams.

Bryan

[Andrew Nabb]

I only had time to dyno one of our (kettering's) shock on the shock dyno at work. To be honest, you get what you pay for with the mountain bike shocks, in particular with regard to the adjustability of the shock via clickers. To summarize, lets just say after 3 or 4 clicks out of 15 the dampning values go from useable to insane.

This is actually due to the fact that the shocks are designed to handle much higher dampning rates and spring rates than some of the cars use. Risse only sells springs of about 200lbs/inch or higher, which should give you an idea of what the shock was designed for (motion ratio's of .75 or numerically lower). IF you are running higher motion ratio's (we did) be prepared to do some work with pulling out main valving shims and or opening some of the ports up in the piston. Sticktion will also probally become an issue, as will gas pressure in the shocks (risse sent ours with 75 psi of gas pressure, which will raise you wheel rate slightly).

FYI you need to know the motion ratio of the shock in the bike to really guage shock loads.

At least they aren't the penski 7800 (nascar) shocks i work with at TRD.

[KU_Racing]

seth, arent you getting too old for these forums?

we did have shock test data last year dude.

[Andrew Nabb]

We had data from 2002. IS that is what you were thinking about? Remember back then we were running the shorter stroke risse shocks at a motion ratio of .5, and so the shock test speeds were different. Subsequently the shock displacements will be much smaller, which should make the shocks less consistant (cavitation and fluid compressablity and other effects make more pronounced changes with small displacements). Those shocks were also built much differently than our current shocks (without going into detail). The 2002 data was done on a rotary dyno, and the stuff i did a few months ago was on a EMA (linear motor) dyno.

It is not seth, this is drew

[KU_Racing]

I know its drew, since it says Andrew Nabb every time you post. Penguins2001 is seth. Anyways, I would swear that I have seen dyno curves for those shocks.. I am almost positive that we had curves that came with them when we bought them. I could be wrong of course..

[Mapes]

has anyone heard of renton coil springs company. They are in washington state. I found them online. Does anyone know what kind of quality they are.

[Marshall Grice]

I've heard of them. no experience with them.

[Andrew Nabb]

Renton is fairly famous amoung the nascar teams. They seem to have fairly good quality at a fairly low price. We have tested and liked rentons at TRD

Of course that is for the 6 inch diameter or so coil springs.

[Mapes]

thanks andrew nabb. I am glad that someone has heard of them. thanks for your help

Mapes

[Mapes]

i have not been able to find a price for ohlins does anyone know how much one of their shocks would be?

Mapes

[JesseS]

call them for the exact price but it is around $550 each.

[LU-Bolton]

Is anyone from teams such as RMIT, Penn State, etc. who run smaller shock setups available to comment on the shcoks they use. I have seen teams like Queen's and Delft in the past run the mtb. setup. Our team has a little experience with both the fox vanilla rc's and the risse shocks. We love the packaging, but feel the quality is definitely suspect. Plus, it's difficult to drop over $2000 on a set of ohlins shocks when a mtb. setup can easily cost under a grand. Not to say that the $2000 isn't justifiable. Just wondering what some of these other guys are running because I know our team as well would like to switch if we could find something else.

[Andrew Nabb]

The mountain bike shocks can work well for you if you plan on having to refill them with oil ocassionally (once or twice a year) and fairly regularly refilling them with gas pressure. After 5 or 6 months several of our shocks had no gas pressure in them.

They are obviously cheap and are very easy and simple to rebuild if you have the time and parts.

If you don't have acess to a shock dyno (you don't have to own one, just use it during setup and balancing), don't feel comforatable rebuilding the shocks or don't want to have to take them apart to make large changes....then i would say it is probally time to save up and take the ohlins plundge.

[Mapes]

has anyone out there ever used a penske or koni dampers for their suspension. I saw that pesnske was in the UK so I was just a little curious as to if anyone has heard of them or used them.

Thanks Mapes

[RiNaZ]

we're using penske this year, but havent tested it yet. They do have a location here in daytona beach if you're in the US. It cost us about a grand for two shocks.

[Mapes]

does anyone know of Koni shocks. Are they any good. Has anyone ever had any problems with them?
Thanks RiNaZ for the info.
Mapes

[Mapes]

This is for anyone from cornell. When you used the tanner shocks back in 2002 I was wondering on how the performance was when you used them. If you could I would like any available information you could give me on the matter. Thanks a lot.

Mapes

[Twonius]

Everyone is missing out on the tanners and the penske 7800's. Sure they arn't externally adjustable (you can get a bleed adjuster for the penske). But we were very pleased with the setup on our Penskes last year. Part of that is when you order them someone with years of experience will be setting them up with a basic tune which will be lightyears better than what comes stock on a mountain bike.

[Andrew Nabb]

Risse shocks are also valved specifically for the motion ratio and dampning estimates you give them. I am still playing with what we were sent last year, but it was a workable starting point.
I looked back at my previous post and I incorrectly said I worked on 7800 series shocks at TRD. I work with the 7300, which are the aluminum bodied nascar shocks from penski.

[Chris Boon]

hey people, i was wondering if anyone has had experience with SACHS shocks? Also does anyone have any recommendations in relation to springs?