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Converting to rigid forks

grelvingrelvin Posts: 16
edited February 2011 in Commuting general
Hi all,

Been looking at converting to rigid forks for a while now, is it worth doing?
I have a 12 mile round trip commute, mostly road with a short section on a farm track.
Dont want to spend much if I do go down that route, have been looking at On One's standard rigid fork @35 quid.
I currently have Suntour XCR I think, which are 80mm travel, lockout etc. Getting on for 2.5kg so would be nice to cut down on weight.
Would it be easy enough to switch between suspension and rigid when the time comes aswell? I do occasionly go to Llandegla when I can get there.
What things would I need to consider before changing? I also currently run V-brakes, cant justify discs for such a short and easy commute.

Cheers,

Graeme

Posts

  • grelvin wrote:
    Hi all,

    Been looking at converting to rigid forks for a while now, is it worth doing?
    I have a 12 mile round trip commute, mostly road with a short section on a farm track.
    Dont want to spend much if I do go down that route, have been looking at On One's standard rigid fork @35 quid.
    I currently have Suntour XCR I think, which are 80mm travel, lockout etc. Getting on for 2.5kg so would be nice to cut down on weight.
    Would it be easy enough to switch between suspension and rigid when the time comes aswell? I do occasionly go to Llandegla when I can get there.
    What things would I need to consider before changing? I also currently run V-brakes, cant justify discs for such a short and easy commute.

    Cheers,

    Graeme

    Hi Graeme,
    I swopped out some old suspension forks for rigid forks on the mountain bike I use as a commuter and consider it worthwhile. Benefits of swapping over to the rigid fork were
    * able to fit full mudguards on the rigid fork
    * less energy lost by the rigid fork especially if climbing standing on the pedals
    * less weight
    Main consideration is you have to find a rigid fork that is the right length, usually referred to as suspension corrected.
    Disadvantage I found is the rigid fork feels a bit harsh if you ride for several hours as my one doesn't flex or give that much. Solution is to get some decent bar grips.
    Swapping between the rigid fork and non-rigid fork is something I find a bit of a pain, I can do it but need to allow about an hour for fiddling with re-adjusting hand bars, swopping brake to new fork and sorting out the aheadset tapered bushing washer. I sometimes struggle to get the tapered washer out and have sometimes damaged it when swapping forks. ( some mechanic will probably tell me I've missed some incredibly obvious way of doing it )

    regards

    James
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    FCN = 8
  • jairajjairaj Posts: 3,009
    I swapped out my old and very budget RST forks for Exotic carbon rigid forks. Not only did I save a tonne of weight from the front and saved waisted energy but I found the bike actually behaved better. the old forks were like a pogo stick and lead to nervous handling. the rigid forks are more stable and predicable and I prefer them to the old forks even when riding off road.

    You can counter balance the stiffness using a few methods. A large volume but quick rolling tyre will help the most. When riding off road I use a Specialized Captain 2.2 this balloons up and if run soft provides a substantial amount of cushioning. When riding on road I use Schwalbe Kojaks again large width and run soft ish.

    Soft grips will help a lot too and finally a forgiving handle bar will help too although I found the difference here was not as noticeable as the tyre change.

    To find the correct forks for your use, measure your current axle to crown length and take of 20% or so for the sag. This is know as suspension corrected axle to crown length. Then find a fork with a similar length and with v-brake bosses and the correct steerer size and you are sorted.
  • nicklousenicklouse Posts: 50,675 Lives Here
    TBH i would just buy a quality carbon fork and use that for everything.

    but if you want to use two forks I would look at a new headset and get two crown races so you dont need to swap them over each time you want to change forks.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The RookieThe Rookie Posts: 27,757
    I swapped from Suntours to Rigid on my commuter, Onza smart guy's, they cost me £45 and I sold the suspension forks for £25 so it was hardly an expensive way to loose 1.5Kg, the bike was much nicer to ride as a commuter after that.

    Onza still sell them on ebay if you are on discs http://cgi.ebay.co.uk/Onza-Smart-Guy-Fo ... 5197c146f2

    Simon
  • You would need a suspension corrected fork. There is a fair chance that an off the shelf fork won't work too well.

    Thorn provide a rigid fork to replace suspension (http://www.sjscycles.com/thornpdf/ThornMtTuraForkLoRes.pdf).

    It may make sense to swap forks over if you have a good quality bike that you want to use for different purposes, but I wouldn't want to be swapping back and forth too often (maybe I'm just lazy).

    As others have said, a decent carbon fork will save a chunk of weight, and soak up the bumps pretty well. Not sure I'd use one for extreme downhilling but fine for light off road use, and excellent for commuting.
    Nobody told me we had a communication problem
  • The RookieThe Rookie Posts: 27,757
    You would need a suspension corrected fork. There is a fair chance that an off the shelf fork won't work too well.
    EH? Just compare the axle to crown height of the rigid versus the sus (at normal sag) not exactly rocket science! Most rigids for MTB's have a target travel they match to, my Onza's look like 90mm (that is they can replace 80 and 100's OK).

    Simon
  • You would need a suspension corrected fork. There is a fair chance that an off the shelf fork won't work too well.
    EH? Just compare the axle to crown height of the rigid versus the sus (at normal sag) not exactly rocket science! Most rigids for MTB's have a target travel they match to, my Onza's look like 90mm (that is they can replace 80 and 100's OK).

    Simon

    You may well be correct Simon. I based my response on advice I was given by Thorn. I have a Sterling and the 'recommended rigid fork' at the time retailed at about £140 (according to the link I provided earlier this has now been reduced to £99). Thorn were selling other steel touring forks from about £30, and carbon ones from £70. I enquired about fitting these instead and was advised that because they were not 'suspension corrected' that the wheel base and handling would be affected, so they recommended not to fit these.

    In the end I have just left the suspension fork on. It locks out and is pretty light anyway, and I have other bikes to commute on.

    Edit - Thorn's literature states:
    "The forks have an L1 dimension (centre of axle to crown race seat) of 430mm. (This compensates perfectly for either 80mm or 100mm travel forks, either of which actually rides at around 430mm in neutral conditions). The increased offset (52mm) of the Mt.- Tura forks improves the steering characteristics of most mountain bikes apart from extreme off road use!"
    Presumably 'off-the-shelf' forks would have a sub-optimum offset and L1 dimension?!?
    Nobody told me we had a communication problem
  • The RookieThe Rookie Posts: 27,757
    You may well be correct Simon. I based my response on advice I was given by Thorn. I have a Sterling and the 'recommended rigid fork' at the time retailed at about £140 (according to the link I provided earlier this has now been reduced to £99).

    "The forks have an L1 dimension (centre of axle to crown race seat) of 430mm. (This compensates perfectly for either 80mm or 100mm travel forks

    OK I understand, but really its not hard, measure it, get a fork the right length or close to.

    Love that BS from them, compensate 'perfectly' (erm their is only one perfect, the rest is acceptable/good enough/OK/will do/won't kill you) for 2 different lengths - pure marketing BS.

    Simon
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