Proflex Girvin front shock (Oil damped, NOT polymer)

Discussion in 'Shop Talk' started by Rob G, Sep 4, 2018.

  1. Rob G

    Rob G Newbie with Hope!

    Location:
    349 miles north of Canada
    Name:
    Rob G
    Current Bike:
    Proflex Beast. Giant ATX
    Hello all.
    By way of introduction, I'm a casual mtn. biker, bought my first (and only) bike back in '97 on the East Coast.
    It's a ProFlex Beast with Mavic 238 rims, SRAM 9.0 grip shifts and derailleurs, Magura hydraulic rim brakes, updated saddle. Other than tires/tubes, it's all the same stuff from '97, and it does what I need it to do.
    It has the oil-damped shocks front and rear (not the elastomer stuff).

    Now that my son is getting into mtn. biking, we've been spending more and more time riding together (he's got a Giant ATX that suffered a cracked hub tube and a broken derailleur within the past two weeks. The derailleur got replaced by my original Deore XT that's been sitting in a box for 20 years :)

    Anyway, after riding some pretty rough trails this wekend, I tried to back off the adjuster on the front shock to make it a little softer. Although it's very clean. the collar seems to be seized to the shaft.
    I'm thinking it's done and will have to be replaced.

    My question is: Can I put a shock in there that's normally used for rear setups (since no small shocks seem to exist for front suspension like the Girvin has), or would it be too stiff since it would be set up to take more impact force?

    I don't want to spend the $200 for a Reese unit, 'was thinking more like the $50-$60 units that can be found on auction sites (since they match the length of the original).

    Rob
     
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  2. mtnbikej

    mtnbikej J-Zilla

    Location:
    Orange
    Name:
    J
    Current Bike:
    SC Chameleon SS
    I wouldn’t recommend it.

    @Mikie may have parts....if not, look for something newer. Kids have a tendency to ride hard, and a 20 year old bike scares me.
     
  3. Rob G

    Rob G Newbie with Hope!

    Location:
    349 miles north of Canada
    Name:
    Rob G
    Current Bike:
    Proflex Beast. Giant ATX
    It's for me, and the bike has had an easy life (smooth single track and dirt road easy).
    Would using a rear shock on the front just make the ride even more rough?
     
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  4. mtnbikej

    mtnbikej J-Zilla

    Location:
    Orange
    Name:
    J
    Current Bike:
    SC Chameleon SS

    I don’t know.....but I’m not willing to bet my teeth on it. If you have good dental insurance....try it out and see.

    Certain things on a bike I’m not willing to alter for safety reasons.
     
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  5. Mikie

    Mikie Admin/iMTB Hooligan

    Location:
    Lebec, California
    Name:
    Mikie Watson
    Current Bike:
    Yeti ASR5c, SC Hightower
    Hey @Rob G
    Always helps if you post pics.
    I imagine your shock is a little harsh since you are 349 miles North of Canada!
    Elastomers totally react to temperature.
    You really have two options:
    1. I highly recommend going with the Risse front Shock. It solves all your problems and if you are going to insist on hanging on to an antiquated bike like a '97 it is a long term solution. I had a 1997 857 Proflex, but that was in 1997! :)
    https://www.risseracing.com/proflex.shtml
    I would sell you one but everyone bought all I had in stock!
    1. Your other option is there are a couple companies that make elastomers for your shock. With the lower temperature range I do not recommend it, but that is your best inexpensive option.
    https://www.suspensionforkparts.net/eshop/proflex.html?page=all

    Going with a product that is not designed for your bike is simply dangerous and I would absolutely NOT recommend it. I imagine you want to "keep" riding with your son, so please do the right thing for your safety and his safety as well, and obtain a product designed for your 1997 steed!
    ;)I hope this helps.

    Mikie
     
  6. Rob G

    Rob G Newbie with Hope!

    Location:
    349 miles north of Canada
    Name:
    Rob G
    Current Bike:
    Proflex Beast. Giant ATX
    Hmm, so you're thinking using a rear shock up front would cause catastrophic failure of the shock?
     
  7. Mikie

    Mikie Admin/iMTB Hooligan

    Location:
    Lebec, California
    Name:
    Mikie Watson
    Current Bike:
    Yeti ASR5c, SC Hightower
    Hey Rob!
    He is just suggesting sticking to OEM or a solid designed after market so it ensures your safety. Lord knows I have seen my share of catastrophic crashes on perfectly good equipment. Why lessen your chances with a product not specifically deigned for your bike?
     
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  8. mtnbikej

    mtnbikej J-Zilla

    Location:
    Orange
    Name:
    J
    Current Bike:
    SC Chameleon SS

    Let’s just for shits and giggles think about this for a second.

    You mount a rear shock in place of the stick elastomers. Let’s say it is too stiff. Where do you think all that energy is going?

    Let’s try something different. What if you put a steel rod in place of the elastomers and ride it over a rough trail. The rod will be too stiff, so all that energy goes where? It goes into the hardware. It goes into the shock mounts. Now we are talking about 1997 engineering, but I highly doubt they designed that fork to take that much stress.

    Again, I’m not willing to bet my pearly whites to test it out.

    I know they call it common sense, but sometimes I wonder how common it truely is.

    You seem pretty set on trying it. Maybe it’ll work, maybe it won’t. Just not a part I want to be riding along with wondering if this bump is going to be the one that was one bump too many.
     
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  9. Rob G

    Rob G Newbie with Hope!

    Location:
    349 miles north of Canada
    Name:
    Rob G
    Current Bike:
    Proflex Beast. Giant ATX
    No elastomers on these. They're the ODS ("oil damped system" coilovers). That's why I was hoping a similarly designed shock could be put in there (image below just for example to show a similarly designed component - it looks more similar to original than the Risse does). I'll add a picture of the shock I have to this post when I get home (no luck finding a pic with Google). It didn't seem like an incredibly high-tech unit; I figured (hoped?) the coilover shocks of today would be just as good if not better.

    I'm thinking I may just put it all back together and ride the season out with it too tight, then get it down to the shop during the cold weather and see what they can do with it (while I watch eBay to see if any of the shocks come up for sale without buying a full fork).
    I thought a lot more experimenting (parts swapping) would be happening with this stuff like int he old days, but I suppose most everything has been figured out by now.

    Time passages. Getting old sucks!


    Sorry, I've tried a dozen times to remove the double-link for the pic, but the software won't allow it!

    71BOsxhPywL._SX466_.jpg
     
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  10. Mikie

    Mikie Admin/iMTB Hooligan

    Location:
    Lebec, California
    Name:
    Mikie Watson
    Current Bike:
    Yeti ASR5c, SC Hightower
    I'm not sure about the sunsets, but thanks!
    I have a boat load of springs that will probably fit that very Noleen looking shock.
    Are you saying the big ole nut on the bottom of that shock is locked up and you can't spin it? Other wise the shock works just fine?
    I'm thinking that a nice penetrating oil bath will get that tensioner bolt moving and if the spring is too harsh, let me know how many pound spring it is, and get me dimensions: Spring length, outer dimension (OD), and inner dimension (ID) and I might have some spring options for you.

    :)Mikie
     
  11. Rob G

    Rob G Newbie with Hope!

    Location:
    349 miles north of Canada
    Name:
    Rob G
    Current Bike:
    Proflex Beast. Giant ATX
    Thank you very much for the offer!
    This is actually a Girvin shock and it's the aluminum collar nut that would be on top when on the bike. It has a yellow spring, and a gold shock body, and the only marking on the spring is a small printed "253".

    The last time I adjusted it was to tighten it down to provide a firmer ride on hard-pack, many years ago. Perhaps that was NOT the right way to provide a slightly firmer ride. I wanted to loosen it up for a little more give as the trails we have here are a little more rough. It still works fine, and can be used for the rest of the season (it can be fixed over the winter).

    My concern is that the metal in the threads galled as it looks very clean and no corrosion is visible at all, but it is locked as tight as tight can be. I bet it'll have to be cut off and replaced if it's ever to work again (and what are the odds of finding another collar? :)
    It's soaking with some penetrant just in case it CAN be broken free.

    I'm afraid the sunsets reference went right over my head.

    IMG_0983.jpg
     
  12. herzalot

    herzalot iMTB Hooligan

    Location:
    Laguna Beach
    Name:
    Chris
    Current Bike:
    '15 Intense Tracer 275c DVOish
    Resurrecting old bikes can be a passion, or an exercise in futility. Maybe treat yourself to a more recent bike for under $1000? The Proflex were great in their day, but even if made rideable, will it be safe?
     
  13. Rob G

    Rob G Newbie with Hope!

    Location:
    349 miles north of Canada
    Name:
    Rob G
    Current Bike:
    Proflex Beast. Giant ATX
    Too far gone because the spring collar is mucked up? Wow. Two weeks ago, I had to have the rear wheel trued for the first time since it was new. It's first replacement set of brake pads since new are on the way.

    I suppose you replace your bike every time a part breaks?
    I'll send you my PayPal address. You can send me the thousand bucks and I'll buy a new bike to make you happy.
    Next time your car needs tires, just send me the title. I'll take it off your hands while you buy a new one.

    And now, back to the folks who seem to give a damn and are willing to help a fellow out.
     
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  14. herzalot

    herzalot iMTB Hooligan

    Location:
    Laguna Beach
    Name:
    Chris
    Current Bike:
    '15 Intense Tracer 275c DVOish
    My apologies Rob G. I will modify my post to reflect my intentions.

    It's very difficult to resurrect a 1997 bike with proprietary parts. Probably not as easy as replacing a seized collar. I appreciate that people want to bring their old steeds back to life, but if it's riding that is the priority, perhaps a good used bike that's ten years newer can be had for a reasonable price.

    Carry on.
     
  15. Danimal

    Danimal Well-Known Member

    Location:
    Mission Viejo
    Name:
    Dan
    Current Bike:
    Rocky Mountain Altitude
    This is an accurate assessment and not intended as a slight .
    Perhaps a newer bike for riding and the proflex as a collectors item.
     
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  16. mtnbikej

    mtnbikej J-Zilla

    Location:
    Orange
    Name:
    J
    Current Bike:
    SC Chameleon SS

    No offense but you were the asking about putting a rear shock on the front of your bike....so you gave us the impression that it was done. Proprietary parts that are 20 years old in the bike industry usually mean that you move onto something more modern.

    We answered that question.

    I also suggest that when you are the new guy asking for help, you ease up on the attitude.

    Good luck with the fork/bike.
     
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  17. Mikie

    Mikie Admin/iMTB Hooligan

    Location:
    Lebec, California
    Name:
    Mikie Watson
    Current Bike:
    Yeti ASR5c, SC Hightower
    I fixed it for you. You uploaded the image twice, so the software was just doing what you asked it to do. :)

    You posted up two pics of a sunset, so I was kinda lost on that too, ha hah! But the links to them are now broken so I fixed that for you as well.

    We want to help. The intentions are good. You were just kinda taking us on a journey to get to the meat of the issue.

    So is THIS, the actual pic of Your shock?
    img_0983-jpg.43604.jpg

    If it is, then you are correct in your thoughts. Tightening does (to a point) adjust some of the ride. It is a very minor spring load adjustment. The better option would be to obtain a spring that better fits the most general ride conditions you experience. Those springs are pretty common, and like I said earlier, I have a box of them. I believe that Proflex bought out Noleen who was their "next step" suspension supplier after the Elastomer phase, thus the evolution to the above shock. Noleen had a significant quality issue with the seals being installed incorrectly which gave them a very bad reputation for a time being. I had actually visited their manufacturing site when they were scrambling to fix them all for free.

    I suspect the aluminum on aluminum has set up some electrolysis/corrosion. If when you do pull the shock off and you check to see if the body is still dampening and still want to soften the ride, hopefully I have a shock spring that is lighter to the degree you are looking for. I would be happy to assist.

    If you are looking for an aftermarket shock, go for one that is designed and spec'ed to replace an OEM shock on a Girvin Vector fork, otherwise you could be setting yourself up for disaster and I would hate to see that happen to yah...

    I hope this helps!

    :)Mike
     
  18. Cyclotourist

    Cyclotourist iMTB Addict

    Location:
    Redlands
    Name:
    David
    Current Bike:
    Santa Cruz Chameleon
    Go for it, what could go wrong?!?!?!
     
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  19. Rob G

    Rob G Newbie with Hope!

    Location:
    349 miles north of Canada
    Name:
    Rob G
    Current Bike:
    Proflex Beast. Giant ATX
    The attitude was well-based from some of the answers that were offered. If I ask for help with technical info on a part and am told to just replace the bike, it makes me feel slighted, especially if it seems to be an answer to avoid the question, and especially since the entire suspension MTB hobby was borne from people experimenting (like my friend who grafted a dirt bike front fork onto a bicycle in 1981. It weighed a TON, but it looked cool coasting down a hill).

    I tried to be very clear in my original post as to what I had, and what I was wondering if I could do (I even mentioned in my subject line that the shock was oil-damped and NOT polymer, but got several replies that my polymer shock probably needed new polymers/elastomers).

    If someone doesn't know the spec differences, that's fine. It's an old bike. But, claiming something can't or shouldn't be done without knowing the WHY seems kind of silly (i.e. I could tell you why a certain turbo wouldn't work well for a given application if I know the specs of the turbo. I'd never say a non-speced turbo wouldn't work just because. How could I possibly know?).

    The part in question is not something designed for space travel. It's a simple oil-damped coilover shock that replaced an even simpler elastomer-damped coilover shock. I was asking if a rear shock from "today" would have similar properties. I know that on a car, they would be different due to the weight biases from the various engine mounting schemes. I don't know if the issue would be the same on a bike, since there is no "engine" and the rider will (on average) be centered between the front and rear.
    I was hoping that someone who has "been there, done that" might say "Nope. A rear shock is much too stiff for that application" or ""Yep. it'll work, but you'll have to compress the spring a bit or the ride will be soft" or "You could give it a shot. The front spring on that old tank was a 700 pound rating. the new ones are only 750".

    I used to ask for similar advice from Eibach when trying out race springs on cars they weren't originally designed for. "Nope. that spring was designed for a front engine car. Not gonna do well in that Porsche 911. Too much weight in the rear" or "It'll work fine as long as you don't mind the car being 1/2" lower. Make sure you aren't going to have tire rub with the fender lip"
    Cool.

    I figured I would check a source for MTB info to see if anyone had the knowledge before giving it a try/experimenting. It's fine that no one knows. I'll just reassemble the bike and continue to ride with the shock as-is until I have a shop look at it, or just buy a new fork.
    At my age, a thousand bucks ain't a worthwhile investment for a used bike. With one kid in college and one in private school, a few thousand for a new bike ain't gonna' happen.

    Thanks again.
     
  20. mtnbikej

    mtnbikej J-Zilla

    Location:
    Orange
    Name:
    J
    Current Bike:
    SC Chameleon SS
    You are asking for advice about a vintage part that only a small % of riders have experience with from a smaller group of riders. You are only here because Mikie has sold some Parts so it comes up in a search.

    Lots of us here have a lot of experience and decades of riding....some in an around the bike industry for years, so just maybe we have a clue.

    I see you posted on MtBr.....hopefully you’ll get the answer you want to hear, as there are 100,000’s Of members there.

    Like I said before good luck with it all.
     
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