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Old 05-11-2013, 04:26 AM   #556
Colebatch
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Quote:
Originally Posted by alpi View Post
Question is: can someone confirm the stock triple clamp offset (25 mm ?) vs acceptable KTM equivalent for 4860? Lukas was saying in #122: "KTM triple clamps have 20mm offset vs. the stock 25mm", but is that 5 mm variation in offset not without some instability consequences ?
You have to measure the total offset ... not just the triple clamp offset. The offset in the axle clamps (perpendicular distance between the centreline of the fork to the centre of the axle hole) has to be added to the offset in the triple clamps.

I remember when I changed 3 years ago from the BMW triples and BMW axle clamps to the KTM 20mm triples and standard KTM axle clamps, I barely noticed a difference ... the steering remained inherently stable. If anything, its even a touch more stable.

From memory the KTM axle clamps have more offset (I think about 3 mm) than the stock XC ones (that largely countered the fact that the BMW triple clamp offset was 5 mm more) ... and so the total offset was different by only 2mm (less offset via the KTM setup).

Less offset = more trail = more stability, so the 2mm less offset (total offset) in the KTM setup delivered more stability to the front wheel.
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Colebatch screwed with this post 05-18-2013 at 08:05 AM
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Old 05-11-2013, 05:30 AM   #557
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Quote:
Originally Posted by aprilian View Post
ping inmate mbfj40, he had a complete set of forks for less than that one part.
Thanks, I checked the thread and I believe his forks came off an X=Country. I have an X-Challenge and I think the travel is less on an x-country....????
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Old 05-11-2013, 07:49 AM   #558
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Originally Posted by gsstampeder View Post
Thanks, I checked the thread and I believe his forks came off an X=Country. I have an X-Challenge and I think the travel is less on an x-country....????
X-Challenge has 270mm fork travel
2007-2008 X-Country has 240mm
2009 X-Country has 220mm
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Old 05-11-2013, 09:09 AM   #559
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I thought (and read, and measured) it was 280 for xchallenge...
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Old 05-11-2013, 10:57 AM   #560
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That mbfj40 guy has both a set of XCountry forks with 232mm (9.4") travel and a set of XMoto forks with 270mm (10.6"). Numbers from BMW sales brochure. It also implies that XMoto and Xchallenge travel is the same.
BMW Microfiche calls out the same part numbers for the XChallenge and the XMoto for the damping units:
31427708795- Damper unit, left
31427708796- Damper unit, right

mike :-)

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Old 05-11-2013, 11:17 AM   #561
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You're right! My bad....
The length of the chromed part of the forks is ~280 mm, so that stuck with me...
So that extra length - is it for dirt to be pushed out to when the bike bottoms out?
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Old 05-11-2013, 01:04 PM   #562
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Thanks all for the help. I picked the bike up this morning and talked to the tech that diagnosed the catastrophe. As he was explaining to me that the one shock purged easily while the other would not. It was like a pogo...I explained that one fork was for compression, the other was rebound (I do believe that is how it works ...isn't it?) Once he heard that it 'all made sense' then.

I took the bike out for a nice spirited ride over some back road gravel and a few trails and it seems to be working fine. Great actually...well at least for what I'm capable of pushing it. I do have some wear marks on the chrome tubes that I guess is ok. Normal wear? I'll pick up some neoprene fork socks and protect the seals a bit better, but otherwise all seems to be good.

Sorry for the false alarm and thanks again for offering help.
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Old 05-23-2013, 02:18 AM   #563
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looking at seeing if can get funds to fit some wp43 forks

curious, if i remove and replace lower cast sections i have to machine the out to allow the lower adjusted to fit into the bmw cast section

if i fit full forks and keep stock wp unit, can i just make up spacers to shim wheel centred or does it greatly affect the calliper also?

reason being is i want to try sell my own xch forks so would rather not remove the cast legs
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Old 05-23-2013, 02:42 AM   #564
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I would also sell your stock forks complete, you should be able to get more for them than you pay for the WPs. Find somebody in a strict TÜV country like Germany, where forks different from stock are illegal.

Then you just need a new axle, wheel spacers and caliper bracket.
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Old 05-23-2013, 03:00 AM   #565
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I understand WP 43 mm can be fitted into original triple clamps...
If one were to go with forks that required different mounting diameter (WP 45, Marzocchi 50, etc...), are there any other bikes which use stock 210mm fork spacing?
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Old 05-23-2013, 03:00 AM   #566
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Originally Posted by LukasM View Post
I would also sell your stock forks complete, you should be able to get more for them than you pay for the WPs. Find somebody in a strict TÜV country like Germany, where forks different from stock are illegal.

Then you just need a new axle, wheel spacers and caliper bracket.
yes very true.

made up plenty axels for bike so thats simple job.

more likely use bmw axel and press aluminium rod onto them then turn it down to suit fork leg diameter

had look some proposed irish laws and soon non stock parts may be illegal here too. better mod the heck outa my 2 bikes so
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Old 05-23-2013, 08:20 AM   #567
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Originally Posted by Bli55 View Post
I understand WP 43 mm can be fitted into original triple clamps...
If one were to go with forks that required different mounting diameter (WP 45, Marzocchi 50, etc...), are there any other bikes which use stock 210mm fork spacing?
not really.

If you go for other forks, then you basically need to get the triple clamps from the bike you got the forks with.

It is worth noting that Erik at Hot Rod was looking into making a lower triple clamp to fit WP 48mm forks into the XC with 210mm spacing.

He is able to reuse the top triple clamp because its 54mm diameter - same as the WP 48mm top mount. He just needs a 60mm lower clamp with the same offset (25mm) as the BMW one. Depending on what front wheel you wanted to run (keep the XC one or swap to a KTM one) Erik will be able to work out what combination of spacers, axles and brake caliper you need to make that work.
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Old 05-24-2013, 11:03 AM   #568
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Originally Posted by Colebatch View Post
not really.

If you go for other forks, then you basically need to get the triple clamps from the bike you got the forks with.

It is worth nothing that Erik at Hot Rod was looking into making a lower triple clamp to fit WP 48mm forks into the XC with 210mm spacing.

He is able to reuse the top triple clamp because its 54mm diameter - same as the WP 48mm top mount. He just needs a 60mm lower clamp with the same offset (25mm) as the BMW one. Depending on what front wheel you wanted to run (keep the XC one or swap to a KTM one) Erik will be able to work out what combination of spacers, axles and brake caliper you need to make that work.
Emig Racing already has such a product for the X-bikes. I have one on my '08 XCountry with the WP 4860's and it works and fits great. I made up my own axel spacers and brake adapter and am using the stock front wheel. But they offer everything in a complete package if you want. And a replacement top clamp that mounts their steering damper as well. The top clamp/damper assembly can be used with or without the fork conversion kit if you still have money to spend.
mike
http://www.emigracing.com/BMWXConversion.htm


















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Old 05-27-2013, 07:56 AM   #569
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,any thanks to LukasM off here.

xchalleneg forks sold and a serviced set of wp43 on their way to me, and all i had do was post them.

cheers mate very helpfull

must route out some alu bar stock to run off some spacers now
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Old 06-21-2013, 09:19 AM   #570
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I have some Shivers from a Husky 610 and they have the 58mm lowers. I could have them machined to 57mm or have the bottom yokes opened by machining to 58mm.

Alternatively is it possible to use the original Xchallenge upper part (the outer slider) and fit the Shivers parts to that?

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