Damper CAD files

[rwolcott23]

Anyone have a CAD file of the Ohlin ST-44 damper that they would share? It would need to be in a neutral format (IGES, STEP, etc...)

Thanks,
Bob

[rwolcott23]

Anyone have a CAD file of the Ohlin ST-44 damper that they would share? It would need to be in a neutral format (IGES, STEP, etc...)

Thanks,
Bob

[Fyhr]

I'll probably be doing a model of ours in a day or two. But there are several different lengths and sizes of these dampers, which are you after?

[rwolcott23]

I would be interested in the shocks that would accept 2" (51mm) ID springs and a length that is middle of the road. We are early in the design cycle so we will be using this as a place holder in the chassis and suspension design. Once we are further along we will order the dampers and finalize the design.

Thanks,
Bob

[Jersey Tom]

Interesting. The ST44 is that popular? I never got a quote from Ohlins but I would imagine the price per unit would have to be $1000-1500/ea.

If you're early in the design cycle you may want to look at the Cane Creek Double Barrel dampers. Mountain bike dampers, (loosely) based on the TTX40. Four-way adjustable, $550/ea for SAE teams. Easy to package, wide range of adjustability, and superb build quality.

We used them for the first time this year and I think very highly of them, and feel they are a more cost-friendly alternative full-out racecar dampers, which I would have to imagine have a much stiffer rate than one would want on an SAE car, unless you go through and revalve them.

[HenningO]

The cost for the ST44 is about 600 dollars. But why anyone would choose the bulky and heavy ST44 compared to the Cane Creek DBs I have a hard time figuring out.

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What is the weight of the Cane Creek DB? say with and without spring?

[HenningO]

Depends on length.. The DBs are avaliable from like 1 in stroke to around 2.5 inches something

Don't have the numbers in my head, but it's like a third or a fourth compared to a ST-44 with similar stroke

But I wouldn't say weight should be deciding factor when it comes to shocks...

The DBs adjustability with it's decoupled comb/reb adjustments are quite spectacular! Love 'em... Although we only have two on the car...

[rwolcott23]

This isn't for a FSAE car, it is for a DSR. Would the Cane Creek dampers work for a 1000lb car?

Thanks,
Bob

[Jersey Tom]

That all depends on what wheel rates and damping rates you want and what your installation ratio is etc. I would venture to say yes though, with a MR of close to 1. That's just based on having done the kinetics on this year's car. We had to run about 1.7" wheel travel to 1" damper travel to get the rates at the wheels soft enough.

[B Hise]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">depends on what wheel rates and damping rates you want and what your installation ratio is etc. I would venture to say yes though, with a MR of close to 1. That's just based on having done the kinetics on this year's car. We had to run about 1.7" wheel travel to 1" damper travel to get the rates at the wheels soft enough. </div></BLOCKQUOTE>

Cane creek might send you some dyno files if you ask nicely... I haven't had a chance to work with the DB personally, but if it is anything like its parent then it should be sweet ass.

Tom, did you ever take those things apart?

As for the ST44, I think its a fine shock and super easy to re-valve. However, if you don't have/know anyone with a dyno I wouldn't recommend guess and check w/shims.

-Bryan

[rwolcott23]

The ST44 was recomended by someone that I would consider an expert who has a dyno and will be doing the valve work. He does shocks for a living.

Bob

[Jersey Tom]

Never pulled a DB1 apart. Was considering doing some revalving and testing at Colorado State but wound up (a) running out of time and (b) making it work with the stock rates.

They send you dyno plots with every damper you buy! They'll also email em to you.

Softest they go is about 20 lb*s/in. Not sure what they max out at and my computer refuses to open pdfs, but its pretty stiff. The range of adjustment is awesome, high and low speed.

Only thing I'd like is to bring the nose down a little bit, then again if you run a closer to 1:1 MR it may work quite well.

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<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jersey Tom:
Never pulled a DB1 apart. Was considering doing some revalving and testing at Colorado State but wound up (a) running out of time and (b) making it work with the stock rates.

They send you dyno plots with every damper you buy! They'll also email em to you.

Softest they go is about 20 lb*s/in. Not sure what they max out at and my computer refuses to open pdfs, but its pretty stiff. The range of adjustment is awesome, high and low speed.

Only thing I'd like is to bring the nose down a little bit, then again if you run a closer to 1:1 MR it may work quite well. </div></BLOCKQUOTE>

Hi Tom,

Do you know the weight of the DB? 190-50?

[Matt Gignac]

With a 200lb spring, I believe it was something to the tune of 770g.

Matt Gignac
McGill Racing Team

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Thanks Matt,

Thats about half the weight of an ST44 without spring!

[B Hise]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The ST44 was recomended by someone that I would consider an expert who has a dyno and will be doing the valve work. He does shocks for a living. </div></BLOCKQUOTE>

Well then there you go. However, for the 1000lb car, weight and cost of the DB, it might be a better choice. Provided that you can make correct adjustments. 4 ways can be too many ways when you're just getting into things. This explains it best:

"Sometimes I think I would have enjoyed racing more in the days of the friction damper. Since you couldn't do anything much to them or with them, I would have spent a lot less time being confused."

-C Smith.

Tom,

I spoke with cane creek and they strongly suggested no one take apart one of their shocks. That doesn't surprise me given some of the things I have seen. I also haven't bought a set but they were nice enough to send me a graph to evaluate the part. A twin tube like the DB/TTX may also be a pain to bleed by hand. I've never done it, always had a vac machine handy. If you can get it bled well, then taking the nose down in a damper like that is rather easy. Send me a PM and I will lend a few tricks.

-Bryan

[Jersey Tom]

Yea not having taken apart a damper ever, other than a Jupiter 5 after it broke, I wasn't gonna try my hand at taking apart all the goodies and bleeding a 4-way myself. Tony K at CSU would have done such things, so I could sit and watch and say "K. If you break my $550 damper I will hate you forever."

[mtg]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by B Hise:
"Sometimes I think I would have enjoyed racing more in the days of the friction damper. Since you couldn't do anything much to them or with them, I would have spent a lot less time being confused."

-C Smith.

-Bryan </div></BLOCKQUOTE>

I usually tend to agree with the KISS principal quite strongly, but Carroll Smith penned that quote before data aquisition was common place on racecars. With suspension travel sensors and a damper speed histogram, it's pretty easy to make use of a 4 way adjustable damper (especially one that doesn't really have any crosstalk, like the DB).

[B Hise]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I usually tend to agree with the KISS principal quite strongly, but Carroll Smith penned that quote before data aquisition was common place on racecars. With suspension travel sensors and a damper speed histogram, it's pretty easy to make use of a 4 way adjustable damper (especially one that doesn't really have any crosstalk, like the DB). </div></BLOCKQUOTE>


I totally agree, however there are alot of club/semi-pro guys that don't have data systems. Then theres always the people that don't subscribe to the histogram theory... I've found it to be pretty reliable, but there have been times where I've compromised to get a certain balance in one or two corners.

- Bryan

[Kurt Bilinski]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by mtg:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by B Hise:
"Sometimes I think I would have enjoyed racing more in the days of the friction damper. Since you couldn't do anything much to them or with them, I would have spent a lot less time being confused."

-C Smith.

-Bryan </div></BLOCKQUOTE>

I usually tend to agree with the KISS principal quite strongly, but Carroll Smith penned that quote before data aquisition was common place on racecars. With suspension travel sensors and a damper speed histogram, it's pretty easy to make use of a 4 way adjustable damper (especially one that doesn't really have any crosstalk, like the DB). </div></BLOCKQUOTE>

I agree with this, especially giving that the design goal of the FSAE car is to provide a car as to the weekend racer. I think it's fair to assume this customer cannot be counted on to have a shock dyno, nor to demand that they have one as part of the purchase. To require one seems like a bad marketing plan (to this fictitious customer.)

That said, WTF do I know, maybe all good racing shocks these days do demand a dyno. My Konis don't, but then they're considered ancient technology these days...

[B Hise]

I'm not saying that you have to have a dyno to own the car, just to validate valvings. That is all part of the development process, once you have a good base curve (in production), it would be up to the customer to turn the knobs.

[BenB]

Hi Bob and Fyhr, Do you think one of you would be able to send me a copy of the ST-44? Whatever size you have modeled is fine. I am still working out my stroke and body dia so I can change the dimensions around if I need to. Just having the geometry so I can start on the mounting would be a big help though.

bbrubaker@gmail.com
-Ben

[rwolcott23]

Ben,

I still don't have the model but when I do I'll go ahead and pass it along.

Bob

[Fyhr]

Bob, ive sent Ben an email with our dampers, if you'd like to post your address or just send me an email, pontus.fyhr@gmail.com i'd be happy to send em to you.

[Gochi14]

Hi all,
Anyone have the Specs and Cad file of the Ohlin ST- 44 damper? where can i have it in australia?

thanks.

Chi

[TDK]

Could somebody with the willingness to share damper drawings add the to the University of Washington FSAE library for benefit of all teams please? Thank you.

[Paterson]

Anyone willing to post a model of the Cane Creek Double Barrel Shocks... any help would be much appreciated as we have not recieved ours yet.

cheers

Craig

[Fyhr]

Our cane creek double barrel model in ProE .prt is availible at: www.luracing.com/files/canecreekdb.zip (http://www.luracing.com/files/canecreekdb.zip)

Non kinematic Solid Works:
http://www.luracing.com/files/canecreekdbsldasm.zip

edit: spherical bearings missing in the models are M8.

Edit2: our old ST44 model: www.luracing.com/files/ohlinsst44.zip (http://www.luracing.com/files/ohlinsst44.zip)
Pro-E model, not 100% accurate, it lacks a small detail on the damper shaft side, this is the shortest version on the ST44. There are several others availible as well as a slightly longer one (~300mm) with smaller diameter spring.

[Paterson]

Fyhr

Thanks for that. models are great.

Craig