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Supermoto wheels

Discussion in 'The Garage' started by badrock, Feb 1, 2012.

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  1. badrock

    badrock XS650 Member

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    Hi everyone. It's my first post but I'm following the forum since more than a year
    I'm working on a SE from 83 and I want to change the original alloy wheels.
    Initially I was looking from different swingarms that would fit, but I would loose the round look so I decided to stick with the original.

    Finding xs spoken wheels here where I leave is difficult, but cross/motard are easy to come by.
    I've been looking around quite a lot, but could not find any info about fitting supermoto/cross wheels on the xs (cr250/ktm400).

    I have found a couple of 18" supermoto rims+tyres from a ktm, that have the same axle size(17mm in the front and 20mm in the back).
    My may concerns are about the rear wheel, mainly the sprocket alignment, size of the rotor and possibly the rim being too large?:shrug:

    What should I check when buying? :)
    Anyone has experience with it? :)
     
  2. XS771

    XS771 XS650 Addict

    I have a supermoto with 17'' rims and thought it would nice to have 17's front and rear on my xs650 instead of the 19 and 16 . All it would take is some hubs and lace them to 17'' rims plus time and money....
     
  3. GreasyC

    GreasyC XS650 Addict

    If you don't use the stock hubs you'll need to make custom wheel spacers and possibly make changes/spacers to get the disk in the calliper and the sprocket in the right place.

    If you do use the stock hubs you're looking at custom spokes and possibly custom rim drilling. Try Buchanans for that. If you go this route you have to decide what tire sizes you're going to run first so you know which rim to get.
     
  4. badrock

    badrock XS650 Member

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    Thanks for the replies :)

    It's very difficult to find xs hubs here where I leave, in general getting complete wheels is cheaper/easier.

    I'm not afraid of having to build/find spacers for wheels and rotor. I would need a new caliper on the back (I have a drum now) and see if I can find a nice one for the front (the original rotor seams pretty small.. maybe 260mm? :confused:).

    Saturday I'm planing to remove swing arm and wheels, bring them with me and check if it's going to be a nightmare or not :shrug:

    here is a link to the add... let me know what you think.
    http://motoren.marktplaats.nl/onderdelen-overige/520623741-ktm-velgen-18-inch.html

    My concerns are about the rear hub... it looks huuuge :eek:
    For the rim it should not be a problem (people usually fit 18" on the back), and I would change the tyres anyway...
     
  5. gggGary

    gggGary Old guy, NO expert.

    Fitting a sprocket that will provide suitable gearing for the XS may be problematic on supermoto hubs. The large sprocket mounting bolt circle and small OD of a sprocket with gearing suitable for much more than XS pole climbing duties is the issue. Most supermoto wheels are 17s with low profile tires so that adds to the difficulties. I need to figure this out myself. I have set of KTM supermoto wheels and need to adapt them also. But that project is still a ways off. :(
     
  6. badrock

    badrock XS650 Member

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    @gggGary: Thanks, you gave me something to think about! :doh:

    The smallest sprocket I could mount on the ktm wheel is a 38 tooth.. This means that I'll be forced to mount a bigger front spocket (the 18t for the xs or create a curtom one).
    http://www.dropbears.com/u/utilities/sprocket.htm

    mmm.. doing some math:
    - wit the original sizes the ratio is: 1.94~2.00
    - 17t front and 40t back (stock): 2.35 (17% rpm increase :eek:)
    - 18t front and 38t back: 2.11

    so... the only feasible combinatio is 18/38, that would give me a a 5.5% increase in RPM (will run at 5275 RPM when it used to run at 5000 RPM stock)
    Well... I want to build a cafe racer, with good handling for mountain roads... so, I could live with that, traiding top speed for accelleration :D

    The question is more it it's worth it..
    price of the wheels (300$)
    custom spacers (50-100$)
    sprockets (60$)
    new calipers... (probably 50$)
    ...and more that is always there :(

    mmm :shrug: :shrug:
     
  7. gggGary

    gggGary Old guy, NO expert.

    Keep in mind also that the clearance from the sprocket to the clutch push rod is small, I have seen more than one kinked push rod with marks where the chain hit it. My guess is a really loose chain skipped on the sprocket but....
    A 520 chain might help maintain clearances.
     
  8. GreasyC

    GreasyC XS650 Addict

    If you keep the stock rear hub you can keep the stock sprockets, then you just need the right spokes and rim. Might be the more practical route. Keep in mind that supermoto/sport bike tires are usually at least 150mm wide in the rear so they won't fit in the stock xs swingarm. You really need to pick a tire set first and then see what needs to be done to make it fit your bike.
     
  9. gggGary

    gggGary Old guy, NO expert.

    Oh yeah, and an offset front sprocket so the chain clears the wide rear meat.
     
  10. badrock

    badrock XS650 Member

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    Yep, probably the best option would be to stick to the 17t front sprocket. With the 38t on the back it would be a 12% increase in rpm... still doable..

    Yep, that would be the ideal solution... but hubs here are very expensive, double the price than the wheels I'm considering! :confused:

    Do you guys know what's the best width for a rear 18" rim?
    Is there another model that has a similar sized hub I could use? (sr500, cb450...)
     
  11. badrock

    badrock XS650 Member

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    I thought I would share the outcome :D

    Incredibly light compared to the original, and fits very nicely what I have in mind for the bike.

    The rims are 18x2.15", so no problems with clearance.
    I'll need to offset the front sprocket a bit and machine some spacers.

    I have a tokico 4 piston caliper and a 260mm front disk.
    Will the 260mm rotor be enough, or if it better to upgrade to 300-320? :shrug:
     

    Attached Files:

  12. gggGary

    gggGary Old guy, NO expert.

    Just by looks that front rotor needs to be bigger for the heft of a 650 with "cafe racer" desires.
     
  13. JET Improvements

    JET Improvements XS650 Member

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    Denver
    Those rollers look sick! I have been eyeing a similar set on my local craigslist for one of my projects. How close is the clearance in the rear, tire to swing arm? Are you using the stock front tubes with a bracket for the caliper?
     
  14. badrock

    badrock XS650 Member

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    Thanks :thumbsup:

    The clearance on the back is very good, with 130/80/18 tyres and a 2.15" rim I still have more or less 1.5cm on each side (3/5").

    For the front I'm planing to use the stock forks, tokico caliper from a gsxr with a 0.8 cm bracket and a 300-320mm rotor with 1 cm offset.
    I was measuring yesterday... and it's gonna be really tight..
     
  15. Travis

    Travis Staff Member Staff Member

    That looks really good! Do you know what KTM they are from? I'm might look for a set of those hubs.
     
  16. badrock

    badrock XS650 Member

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    Originally they were fitted on a KTM 400 SXC, and it looks like it was produced only in the 1999... very difficult to come by, as most of the motards have 17" rims.

    For the hubs, most of the pre '01 models have the same axle (17mm front and 20mm back) so u should be able to find more models that fit, if you are just look for hubs.

    The problem I'm having now it to find a front rotor from a different bike with the same bolting pattern, and with a cm offset. The thick spokes on this hubs leave no space for a 4 piston caliper :banghead:, and I'm trying to avoid making a spacer between the rotor and the hub.

    Do you guys know if there is an aftermarket disk producer where I can get this info (bolt pattern for different bikes)?
    Is there any bike, that uses a 20mm rear axle and a 220-240mm rotor, from which I can take the back caliper?
     
  17. Travis

    Travis Staff Member Staff Member

    Thanks for the info. I wish I could help you with your search for parts.
     
  18. Hey Johnny Park

    Hey Johnny Park XS650 New Member

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    These dirt bike rotors are very thin. I am sure they are designed to slow a motocross bike, not stop it. I'm looking into buying a XS to chop and build a hardtail bobber. I also have a set of KTM rims and hubs with the newer front axle that is 26mm in diameter. Mine are from an EXC model which are 21 inch from and 18 inch rear.

    I also own a high-end euro Supermoto, Husaberg. It has a thick rear rotor, unlike the dirt bike rotors. It is roughly 5mm in thickness, brand is BRAKING, they should be able hook you up
     

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