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Re: [rootsradicals] Al and suspension

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  • Devian Gilbert
    the added length of the longtail cargo bike changes weight distribution from the traditional bicycle of 30/70% front/rear to about 50/50. Means to say that
    Message 1 of 14 , Nov 19, 2011
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      the added length of the longtail cargo bike changes weight distribution from the traditional bicycle of 30/70% front/rear to about 50/50.  Means to say that the added length effectively adds about 20% of the riders weight to the front of the bike.

      read down to the section regarding suspension.

      with all that said, a suspension fork that can adjust to the demand could work.  at the moment my Big Dummy has a Fox 32 FLOAT 100 RLC.  I weigh in at 180lbs, and have the preload maxed out at 125psi.  it works just fine with a wide range of cargo weights.

      d-
      On Nov 14, 2011, at 8:53 AM, skeem2005 wrote:

       

      Why is front suspension bad for an Xtracycle? I understand rear suspension will not work.

      Is an Aluminum frame strong enough to withstand the torque of the Free Radical?


    • Rich W
      I would add that the long wheelbase of a longtail bike and the large cross section tires typically run make for a quite comfortable ride on pavement with a
      Message 2 of 14 , Nov 19, 2011
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        I would add that the long wheelbase of a longtail bike and the large cross section tires typically run make for a quite comfortable ride on pavement with a normal front fork.

        The problem in doing a longtail conversion is of course that most newer MTBs are only available with suspension front forks. Older non suspension MTBs typically are not fitted with disc brakes which many prefer for longtail cargo bike use.

        Rich Wood

        --- In rootsradicals@yahoogroups.com, "Rich W" <astronut1001@...> wrote:
        >
        > For street use front suspension forks are energy absorbers unless you use one that can be locked out, in which case why have it? For longtail bikes, particularly when loaded, the weight on the front fork is much greater than bicycle suspension front forks are designed for so most compress completely which decreases ground clearance and changes the effective front end geometry of the bike.
        >
        > No one I know of makes a suspension front fork designed for use with the weight of a loaded longtail bike. Things are made worse by the fact that the long wheelbase and normal rider position on a longtail bike increase the weight percentage on the front wheel compared to a normal bike.
        >
        > Rich Wood
        >
        > --- In rootsradicals@yahoogroups.com, "skeem2005" <emilyskopp@> wrote:
        > >
        > > Why is front suspension bad for an Xtracycle? I understand rear suspension will not work.
        > >
        > > Is an Aluminum frame strong enough to withstand the torque of the Free Radical?
        > >
        >
      • Rich W
        Devian; Nice fork but the current version, listed as the Fox Shox 32 FLOAT 100 RLC FIT Fork - 2012 so far as I can determine, lists on Amazon for between
        Message 3 of 14 , Nov 19, 2011
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          Devian;

          Nice fork but the current version, listed as the "Fox Shox 32 FLOAT 100 RLC FIT Fork - 2012" so far as I can determine, lists on Amazon for between $750 and $800 depending on exact version per my quick Google check. NOS 2011 or older ones are presumably available a lot cheaper.

          I presumed that the OP is asking about suspension forks due to difficulty in finding a suitable conversion candidate bike that does not have a cheap suspension front fork installed from the manufacturer. A cheap suspension front fork is, based on posts I have seen here, typically a poor choice for use on a longtail conversion.

          Rich Wood


          --- In rootsradicals@yahoogroups.com, Devian Gilbert <asanacycles@...> wrote:
          >
          > the added length of the longtail cargo bike changes weight distribution from the traditional bicycle of 30/70% front/rear to about 50/50. Means to say that the added length effectively adds about 20% of the riders weight to the front of the bike.
          >
          > see Surly Spew: http://surlybikes.com/info_hole/spew/getting_the_most_from_your_big_dummy
          > read down to the section regarding suspension.
          >
          > with all that said, a suspension fork that can adjust to the demand could work. at the moment my Big Dummy has a Fox 32 FLOAT 100 RLC. I weigh in at 180lbs, and have the preload maxed out at 125psi. it works just fine with a wide range of cargo weights.
          >
          > d-
          > On Nov 14, 2011, at 8:53 AM, skeem2005 wrote:
          >
          > > Why is front suspension bad for an Xtracycle? I understand rear suspension will not work.
          > >
          > > Is an Aluminum frame strong enough to withstand the torque of the Free Radical?
          > >
          > >
          >
        • Cara Lin Bridgman
          My first donor bike for a free radical was an aluminum frame with a suspension fork. I did not like the suspension fork. I can t really say I gave it a fair
          Message 4 of 14 , Nov 19, 2011
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            My first donor bike for a free radical was an aluminum frame with a
            suspension fork. I did not like the suspension fork. I can't really
            say I gave it a fair chance, because I've never ridden an ordinary bike
            with a suspension fork. I ended up trying to lock mine, but it
            wouldn't. When I got my Surly Instigator frame, I gave the original
            bike (with frame and fork and wheels) to my father-in-law. The bike
            (and frame and fork) is still going strong.

            Some of the pictures here
            (http://megaview.com.tw/~caralin/Bike/CL%27sBike/CL%27sBike.html)
            include the bike with the aluminum frame and suspension fork and some of
            the loads I carried with it. This bike is featured in pictures 2-9:
            silver aluminum frame and red suspension fork (and purple pedals...).

            CL
          • Devian Gilbert
            no doubt that usually suspension forks that would work with a cargo bike are expensive. you are correct in stating that most mtbs with suspension forks will
            Message 5 of 14 , Nov 19, 2011
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              no doubt that usually suspension forks that would work with a cargo bike are expensive.  you are correct in stating that most mtbs with suspension forks will be a poor choice for an XtraCycle convert.

              of course there is always an exception to a rule.  I knew a guy with a double crown DH fork on his BD.  Got the fork from an eBay DH frame on the cheap.


              On Nov 19, 2011, at 10:27 PM, Rich W wrote:

               

              Devian;

              Nice fork but the current version, listed as the "Fox Shox 32 FLOAT 100 RLC FIT Fork - 2012" so far as I can determine, lists on Amazon for between $750 and $800 depending on exact version per my quick Google check. NOS 2011 or older ones are presumably available a lot cheaper.

              I presumed that the OP is asking about suspension forks due to difficulty in finding a suitable conversion candidate bike that does not have a cheap suspension front fork installed from the manufacturer. A cheap suspension front fork is, based on posts I have seen here, typically a poor choice for use on a longtail conversion.

              Rich Wood

              --- In rootsradicals@yahoogroups.com, Devian Gilbert <asanacycles@...> wrote:
              >
              > the added length of the longtail cargo bike changes weight distribution from the traditional bicycle of 30/70% front/rear to about 50/50. Means to say that the added length effectively adds about 20% of the riders weight to the front of the bike.
              >
              > see Surly Spew: http://surlybikes.com/info_hole/spew/getting_the_most_from_your_big_dummy
              > read down to the section regarding suspension.
              >
              > with all that said, a suspension fork that can adjust to the demand could work. at the moment my Big Dummy has a Fox 32 FLOAT 100 RLC. I weigh in at 180lbs, and have the preload maxed out at 125psi. it works just fine with a wide range of cargo weights.
              >
              > d-
              > On Nov 14, 2011, at 8:53 AM, skeem2005 wrote:
              >
              > > Why is front suspension bad for an Xtracycle? I understand rear suspension will not work.
              > >
              > > Is an Aluminum frame strong enough to withstand the torque of the Free Radical?
              > >
              > >
              >


            • rayretrovox
              I have cracked two Aluminium frames when fitted with FreeRadical. However my usage is pretty severe, 100Kg loads and jumping off kerbs. Now fitted to an older
              Message 6 of 14 , Nov 20, 2011
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                I have cracked two Aluminium frames when fitted with FreeRadical.

                However my usage is pretty severe, 100Kg loads and jumping off kerbs.

                Now fitted to an older chrome-moly frame, much better feel. Plus I am not waiting for the frame to crack.
              • Dr. Michael Polsinelli
                I have an aluminum frame with front suspension. The front suspension is not ideal but it works. I can haul heavy loads. I dialed out as much play in the fork
                Message 7 of 14 , Nov 20, 2011
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                  I have an aluminum frame with front suspension. The front suspension is
                  not ideal but it works. I can haul heavy loads. I dialed out as much
                  play in the fork as possible (it is still too much). If I can find a
                  proper fork (1" threaded steerer) , I'll upgrade, but otherwise, I'm
                  going to ride the frame into the ground before I replace it. I even have
                  a chromoly rigid mtb that can be switched out, but it would take too
                  much work and my current set up is too comfortable to mess with.

                  Michael
                • TIM_H
                  Found some Heavy Duty Monark Forks,question is what would it take to fit em? A great price too. Anyone know?
                  Message 8 of 14 , Nov 20, 2011
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                    Found some Heavy Duty Monark Forks,question is what would it take to fit em? A great price too.

                    Anyone know?

                    http://losangeles.craigslist.org/wst/bik/2708822029.html



                    --- In rootsradicals@yahoogroups.com, "skeem2005" <emilyskopp@...> wrote:
                    >
                    > Why is front suspension bad for an Xtracycle? I understand rear suspension will not work.
                    >
                    > Is an Aluminum frame strong enough to withstand the torque of the Free Radical?
                    >
                  • Devian Gilbert
                    fitting the fork to a frame depends on compatibility. 1. steer tube diameter 2. headset compatibility to frame and fork 3. Steer tube length vs headtube
                    Message 9 of 14 , Nov 20, 2011
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                      fitting the fork to a frame depends on compatibility.  
                      1.  steer tube diameter
                      2.  headset compatibility to frame and fork
                      3.  Steer tube length vs headtube height, stack height, and stem.
                      4.  Stem compatibility vs headset and steertube types and sizes.
                      5.  finally handlebar... handlebar compatibility to stem.  clamping diameters of both steer tube and handlebar clamp.
                      6.  geometry of frame and fork

                      when I look at the Monark fork, my first impression is that it is not an optimal candidate for a cargo bike.  However, lets say this fork was already on a cruiser type of bicycle and that bike could be a decent cargo bike.

                      if a person were to take a modern MTB and try to put that fork on it, and convert it to a cargo bike... I don't think it would be the best idea.



                      On Nov 20, 2011, at 11:26 AM, TIM_H wrote:

                       



                      Found some Heavy Duty Monark Forks,question is what would it take to fit em? A great price too.

                      Anyone know?

                      http://losangeles.craigslist.org/wst/bik/2708822029.html

                      --- In rootsradicals@yahoogroups.com, "skeem2005" <emilyskopp@...> wrote:
                      >
                      > Why is front suspension bad for an Xtracycle? I understand rear suspension will not work.
                      >
                      > Is an Aluminum frame strong enough to withstand the torque of the Free Radical?
                      >


                    • TIM_H
                      Thanks for that Devian.So it appears there isnt a simple plug n play fork huh.Thats to bad. I was thinking to myself I wonder if any Pedicabs use suspension
                      Message 10 of 14 , Nov 20, 2011
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                        Thanks for that Devian.So it appears there isnt a simple plug n play fork huh.Thats to bad.

                        I was thinking to myself I wonder if any Pedicabs use suspension forks.I did a quick search and found some use heavy duty triple-clamp forks on their bicycles.I assume their not plug n play either?

                        --- In rootsradicals@yahoogroups.com, Devian Gilbert <asanacycles@...> wrote:
                        >
                        > fitting the fork to a frame depends on compatibility.
                        > 1. steer tube diameter
                        > 2. headset compatibility to frame and fork
                        > 3. Steer tube length vs headtube height, stack height, and stem.
                        > 4. Stem compatibility vs headset and steertube types and sizes.
                        > 5. finally handlebar... handlebar compatibility to stem. clamping diameters of both steer tube and handlebar clamp.
                        > 6. geometry of frame and fork
                        >
                        > when I look at the Monark fork, my first impression is that it is not an optimal candidate for a cargo bike. However, lets say this fork was already on a cruiser type of bicycle and that bike could be a decent cargo bike.
                        >
                        > if a person were to take a modern MTB and try to put that fork on it, and convert it to a cargo bike... I don't think it would be the best idea.
                        >
                        >
                        >
                        > On Nov 20, 2011, at 11:26 AM, TIM_H wrote:
                        >
                        > >
                        > >
                        > > Found some Heavy Duty Monark Forks,question is what would it take to fit em? A great price too.
                        > >
                        > > Anyone know?
                        > >
                        > > http://losangeles.craigslist.org/wst/bik/2708822029.html
                        > >
                        > > --- In rootsradicals@yahoogroups.com, "skeem2005" <emilyskopp@> wrote:
                        > > >
                        > > > Why is front suspension bad for an Xtracycle? I understand rear suspension will not work.
                        > > >
                        > > > Is an Aluminum frame strong enough to withstand the torque of the Free Radical?
                        > > >
                        > >
                        > >
                        >
                      • Devian Gilbert
                        the bicycle industry is notorious for lack of linear standards its not like going to the autoparts store and asking for an automotive part for a certain make,
                        Message 11 of 14 , Nov 20, 2011
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                          the bicycle industry is notorious for lack of linear standards
                          its not like going to the autoparts store and asking for an automotive part for a certain make, model and year of vehicle.

                          as with most bicycle projects, an direct method is to simply start out with a parts list and try to accurately spec a project.

                          what do you have in mind?

                          d-
                          On Nov 20, 2011, at 12:30 PM, TIM_H wrote:

                           



                          Thanks for that Devian.So it appears there isnt a simple plug n play fork huh.Thats to bad.

                          I was thinking to myself I wonder if any Pedicabs use suspension forks.I did a quick search and found some use heavy duty triple-clamp forks on their bicycles.I assume their not plug n play either?

                          --- In rootsradicals@yahoogroups.com, Devian Gilbert <asanacycles@...> wrote:
                          >
                          > fitting the fork to a frame depends on compatibility.
                          > 1. steer tube diameter
                          > 2. headset compatibility to frame and fork
                          > 3. Steer tube length vs headtube height, stack height, and stem.
                          > 4. Stem compatibility vs headset and steertube types and sizes.
                          > 5. finally handlebar... handlebar compatibility to stem. clamping diameters of both steer tube and handlebar clamp.
                          > 6. geometry of frame and fork
                          >
                          > when I look at the Monark fork, my first impression is that it is not an optimal candidate for a cargo bike. However, lets say this fork was already on a cruiser type of bicycle and that bike could be a decent cargo bike.
                          >
                          > if a person were to take a modern MTB and try to put that fork on it, and convert it to a cargo bike... I don't think it would be the best idea.
                          >
                          >
                          >
                          > On Nov 20, 2011, at 11:26 AM, TIM_H wrote:
                          >
                          > >
                          > >
                          > > Found some Heavy Duty Monark Forks,question is what would it take to fit em? A great price too.
                          > >
                          > > Anyone know?
                          > >
                          > > http://losangeles.craigslist.org/wst/bik/2708822029.html
                          > >
                          > > --- In rootsradicals@yahoogroups.com, "skeem2005" <emilyskopp@> wrote:
                          > > >
                          > > > Why is front suspension bad for an Xtracycle? I understand rear suspension will not work.
                          > > >
                          > > > Is an Aluminum frame strong enough to withstand the torque of the Free Radical?
                          > > >
                          > >
                          > >
                          >


                        • Tone
                          Enough people have spoken about the reason why front suspension is not ideal on an Xtracycle, so I will not address it. However, I will speak about aluminum
                          Message 12 of 14 , Nov 21, 2011
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                            Enough people have spoken about the reason why front suspension is not
                            ideal on an Xtracycle, so I will not address it. However, I will speak
                            about aluminum frames.

                            At the moment I have a steel single-framed Surly Big Dummy, which I have
                            had for a couple of years. However, for several years before I “upgraded”
                            to a Big Dummy, I had a few Xtracycle FreeRadical extensions on my
                            Univega 750 FS aluminum frame. I really felt that my old Univega with the
                            long tail extension was a stiffer ride than my Big Dummy. There have been
                            some old discussions about steel versus aluminum on RootsRadicals, so you
                            can search the archives from a couple of years ago to possibly find them.
                            Basically though, steel has some flex in it, but aluminum does not, which
                            is why I think I believe my old Univega had less flexx while loaded.
                            Understand though, while aluminum is lighter than steel and not as prone
                            to rust, it is not as easy to fix a break by welding. Once the aluminum
                            hits beyond its maximum weight/pressure/etc. limit it will break
                            catastrophically, but a steel frame is more likely just to bend slightly
                            and can also likely be bent back without too much concern.

                            In one of the responses someone stated they had cracked two aluminum
                            frames when fitted with a FreeRadical. They also said they carried lots
                            of weight and even jumped off curbs. I have no idea how thick that
                            person’s aluminum frames were, but in my case the Univega 750 FS frame I
                            had was extremely thick. Here is a link to a photo where you can see the
                            thickness of the frame:
                            http://www.cranksgiving.net/XtraLoads/LunarLoad-Angle.jpg
                            Only the seat post had what would be considered normally sized tubing.
                            Even the chain-stays seemed extra thick compared to other steel and
                            aluminum bikes. In fact when I got the Univega I was already working as a
                            bike messenger in NYC and I had broken a chrome-moly frame while on the
                            job. It was the bike mechanic at my local shop, who actually picked out
                            the Univega for me because he knew exactly what kind of treatment I put
                            my bike through... and that was even a few years before I got an
                            Xtracycle. Even later after I became an Xtracycle rider, I ended up
                            breaking three FreeRadical extensions on the Univega before “upgrading”
                            to a Big Dummy.
                            I would not recommend ever hauling a load like the one in the photo, but
                            obviously it shows just how strong the aluminum frame was. Also in the
                            photo you can see that I lock up my bike with a 3’ long 15 pound
                            Kryptonite chain. Working as a full time messenger meant I was locking
                            and unlocking my bike at least 20 times a day, which is why the paint job
                            got scratched and chipped off so much. That chain must have undoubtedly
                            worn into the frame as well. I will say I tried never to jump off curbs
                            that much, especially when loaded... after all I avoided riding on
                            sidewalks as much as possible. In any case, not performing hops or drops
                            on my bike certainly gave the aluminum frame a longer life, but I
                            definitely had my share of collisions. When you are riding a bicycle on
                            NYC streets several hours a day for several years it is statistically
                            unavoidable.
                            Still my Univega-Xtracycle survived all the way until at least a year
                            into living in York, PA, where I commuted by bike about ten miles round
                            trip each day to and from my non-cycling job in almost all weather
                            conditions. Eventually though it did break down after numerous bulky and
                            heavy loads with over 30,000 miles on it. I am not sure that many bike
                            frames, even steel ones, can say the same. So when I “upgraded” to a
                            single-framed steel big dummy I was surprised by how it flexed more when
                            loaded, not to mention it weighed 10-15 more pounds compared to my
                            Univega.

                            In case you are wondering, when my aluminum Univega did break down it
                            seemed to literally tear apart at the lower weld right behind the head
                            tube. It tore almost completely through the down tube from the under-side
                            up. When it finally happened I was commuting to work up a slight hill
                            without any real load and my ride quickly built up a severe wobble. I
                            thought I had a flat in the front wheel or something, but before I could
                            even get both feet on the ground the front wheel rolled out ahead as the
                            bottom bracket and chain rings contacted pavement. I just snapped the
                            rest apart with a little brute bending force from my hands.
                            The winter before there had been a day with snow where I was riding to
                            work and I rear-ended a car. There was low visibility through my slightly
                            fogged up ski-goggles because of the snow, but the driver’s rear lights
                            did not come on to indicate he had stopped, only his running lights had
                            remained lit. When I finally did realize the car in front of me had
                            stopped, I broke as hard as I could on my disc brakes, but the momentum
                            slid me in over the wet asphalt. It did not feel like a hard impact, but
                            it was enough to bend my front fork back so my wheel touched the down
                            tube. The car in front had snow on the back window and if the driver did
                            feel the bump he most likely did not see anyone behind him in his side
                            view mirrors. Considering the awful weather the driver did not even step
                            out of the vehicle and instead just drove off a few seconds after the
                            collision. The car had not sustained any damage because only my front
                            tire had contacted their rear bumper. My 1.5” higher-pressure semi-slick
                            tires were still fully inflated. I had to call my wife to drive me to
                            work in our minivan. Regardless, in retrospect I am pretty sure that bump
                            must have contributed significantly to the eventual frame breakage
                            several months later.

                            I guess in conclusion, you can certainly use an aluminum frame as your
                            Xtracycle donor bike… but just make sure the frame has really thick
                            tubing, avoid curb hopping & dropping, and do not rear-end massive static
                            objects with your front wheel. Ride safe,
                            _TONE_
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