K2 / Proflex Riders Group
General => Tech Forum => Topic started by: Dennis on March 09, 2004, 07:00:51 am
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as we all owe a debt of gratitude to bob girvin for developing the pro-flex bikes, which of course turned into K2 bikes, i was wondering if anyone knows anything about the old girvin flexstem (suspension stem).
I am looking for one to put on my trek 930 that i am turning into a touring machine. I 've already picked up a rock shox sus. seatpost and the frame is on the way to Strong bikes for disc brake mounts. this is going to be one serious touring bike.
anyway, the flexstems that are currently on ebay all use elastomers for the suspension. it seems to me that a while back i may have seen a flexstem with a spring. does anyone know if i am correct and that they were made with either elastomers or regular coil springs?
thanks for any info anyone has on these very oldschool stems.
[smiley=groucho.gif]
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I had one many years ago, think it was one of the early incarnations,thought it was fantastic at the time,suspension forks where all but a dream then,mine fitted via the old quill (expanding wedge within the steerer tube) type stem,the spring system was by small cone shaped elastomers which you could change to various hardnesses,think there where a choice of three,red,yellow&green,I also recall you could get the stem in various colours,only remember yellow or grey,I also remember seeing my first F/S bike at a LBS,it was an Offroad (Proflex) can't remember the model number I think 850 ???the front suspension being the flexstem and the rear a simple elastomer unit operated via a strutt (very similar to the 853).Simon [smiley=nod.gif]
www.fortunecity.de/kunterbunt/schwarzwald/189/bike.htm
http://web.ask.com/web?q=girvin+flexstem+picture&qsrc=I&o=0
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they are still around from some online bike shops.
google and look
or Ebay
[smiley=beer.gif]
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I have seen a couple of Ti Flexstems on ebay. that would be quite an edition to your bike. They seem very rare though...
Trevor
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I own and ride everyday a Profelx 254 which came equipped with the Flexstem. The elastoer is green and still soft after 10 years. I have the aluminum version with a black stem. I guess it works but I like the thing and dont plan to change it. The only problem I ever had is it quit grabbing the steerer tube at one time which as you can imagine, made very hard to actually steer the bike. All I had to do is rough the quill on the front steps a bit and she was good to go. Bike shop guys always ask what it is... anyway, they come up on ebay frequently, watch the stem length... good luck.
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I had the quill/ elastomer model. The side bolts @ the pivot were loosening on every ride. I did loctite the side bolts and they held for a couple rides before I sold it. Did help the arms on street rides.
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Years ago, I saw the softride stem. It had springs and was made of aluminum.
Look it up at bikepro.com
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hey, thanks for all the great info.
i just found an allsop sus. stem (they are apparently still being made) that is a quill (which is what i need) and the add says it can be shimmed for a 1 1/8 steer tube, is that right?
also, i asked the guy if the stem tube itself is 1" (the add says it is a stem for a 1" steer tube). as far as I know, the stem tube dia. for a 1 1/8 steerer tube is 1". any confirmation on this?
[smiley=groucho.gif]
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not quite with you dennis.......my 756 came with the girvin which was a 1 inch steerer but had spacers to work with a 1 and 1/8 headtube.When i switched to the crosslink i had to get a new stem cos the steer tube is 1 and 1/8...the quill and stem is most likely one peice isnt it,so the quill will fit inside the existing
steerer wont it instead of the star nut
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kiwi,
to clarify, my question:
can a quill/stem that is made for a one inch headtube be shimmed to fit a 1 1/8 inch headtube, sounds like the answer is yes from you said. is this correct?
thanks again.
[smiley=groucho.gif]
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I've got an original ("Offroad") Flexstem in my box o'
parts in the basement. 1" steerer for threaded head
sets. Used it for probably 4-5 years before I upgraded
to a RS Judy Fork. It worked ok for taking the edge
off the big hits, but a suspension fork works better.
No museum display would be complete w/o this piece
of mtb history! Make an offer! ;)
- Jeff Gauvin
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I guess it would work with a 1 and 1/8th steerer and may be able to expand enough without shimming.But there is more to it than that.Arent you also faced with converting a threadless headset back to a threaded....my brain hurts.........i cant for the life of me visualize a threaded headset any more.......doesnt the steerer actually have a thread on it for the top bearing retainer and adjustment?
I almost get the felling i dont know what the hell ia am Talking about [smiley=redface.gif] [smiley=diaper.gif] [smiley=turtle.gif]
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kiwi,
this frame I am using has a threaded headset/steerer.
I am not converting a threadless to a threaded.
[smiley=groucho.gif]
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kiwi,
this frame I am using has a threaded headset/steerer.
I am not converting a threadless to a threaded.
see I knew I was making an ass of myself....i forsee no problems for you dennis [smiley=redface.gif]
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can a quill/stem that is made for a one inch headtube be shimmed to fit a 1 1/8 inch headtube[smiley=groucho.gif]
Actually Dennis, I'm not sure that's possible. THere are adaptors if you want to change from threaded to threadless that come in either size, but going from 1" quill to 1 1/8" quill I've never seen an adaptor. Just a shim wouldn't work as it would never give enough "grip" to hold the stem tightly enough. (IMHO).
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I'm pretty sure that when I bought mine you had to purchase either one for a 1" steerer or one for a 1 1/8" steerer,they where size specific,Simon
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i reckon the wedge may expand enough ..and if it doesnt a steel tube with a flange on the bottom could go up inside the steerer to shim it down.1/16 wall thickness.the flange would stop it sliding up
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Hey Dennis. If you did want to get a Girvin, here is one in 1 1/8
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3666614635&category=7295
Trevor