Ok, now a big axle to a small wheel!

[Wobbly]

So I have in my hot little hands a neato KX upside down front end which I'm going to bolt on to the front of the KDX. I'm going to find a cheap front pair of KDX triples to press the stem out and then press it into the KX triples, no drama there.

But the front axle on the KX is 25mm, which is quite a bit bigger than the 20mm one on the KX forks. Going the other way is easy, as I found with the itty bitty KDX 15mm front axle going into the 20mm wheel, but going up in size presents a few problems. With a 5mm jump in ID size I'm not going to be able to handle the diff just by driving in some different bearings into the hub, so an axle solution is necessary.

The only way I can see it being fixed is to have a custom axle turned up and use some sort of crushable bushing on one end that the fork can clamp down on (so the fork bottoms pinch the bushing which in turn pinches on the end of the axle), or by having an end piece that is threaded internally that the 20mm axle screws into that is then pinched by the forks.

The other alternative is to buy a KX front hub and lace up another wheel, but I'd rather re-use the front I've already got if possible....... :-k

[Muzzard]

Staying on the gay 15mm axles, you can use an internally threaded sleeve 25mm outer, 15mm inner, and slotted down one side that sits into the crushable side of the leg clamp, and step the new custom axle same as KX on the other end to suit the opposite arrangement on the fork leg...
Maybe?
Either way you go the end of the axle needs to be bushed by a threaded internally axle end matching correct outer diameter for the fork leg.

[Wobbly]

It'll just need to fit the 20mm DRZ axle and not the 15mm KDX one, so fortunately only half as gay ;)

Yeah, was basically thinking having an axle made up that has a 25mm external diameter that runs from the RHS throught to where the axle should sit up against the bearing, then steps down to 20mm for the remainder of its length in to a threaded section of about the last inch or so. Then have a cylinder of 25mm external diameter and tapped on the inside to match the axle and use an appropriate spacer between the LHS bearing (crush tube actually) and the cylinder to give it something to bite on. That way the axle tightens up solid and the forks clamp on to the native 25mm outers on both sides.

The down side to this is that I might have to run a (heavy) solid axle depending on whether or not I could get it accurately centred and drilled or not, and the cost of having the axle made, which I'm assuming won't be trivial given that it needs either hex heads cut (milled?) into its ends.

Or is a better bet to start with a standard DRZ axle and press on a slieve that slieves it out to 25mm on one end, have the end tapped some more and then have a slieve made up and tapped that screws on to this with a blank section internally that's a slightly larger ID so it can slip over the axle without being an interference fit? That might be OK as long as you don't go banannas with axle torque (which would try and press the axle out of the RHS slieve that was press on to it), but with pinch bolts both sides you shouldn't need to? :-k

[Bomber640]

Sounds like you're on top of it, so I'll keep my shithouse suggestions to myself :)

[Wobbly]

Suggest away, I make a living out of making shithouse suggestions :lol:

Just occured to me that you could press on a slieve on the RHS and then edge weld it without upsetting things. Duh. Then just tap the LHS more than it already is to fit a likewise tapped slieve with an OD of 25mm. Of course that means that you either need to tap the outer part of the slieve to run a big ass nut on to then pinch the whole fork leg assembly together, or alternatively leave a section of thread on the original 20mm axle and rely on a bigger washer to apply the limited amount of force against the fork leg. Given that you have pinch bolts on both sides of the fork legs I'm thinking you only need a small amount of force exerted through this anyway, just enough to take up the slack between the various spacers and bearing sides.... :?:

This is probably all a bit hard to imagine without a drawing :?

[Muzzard]

Sounds like another trip to Bunnings...

[Wobbly]

Ok, so here's another example of why I shouldn't be let close to mechanical devices or sharp instruments :? Brightspark here just measured the ID of the holes in the KX fork and didn't account for the differences in diameter along the axle. The drz has a larger section on the RHS that then steps down to the 20mm axle diameter. The larger section just happens to be 25mm, the exact same as the KX :roll:

Unlike the KX the DRZ has a 20mm hole in the LHS fork with a large nut on the end keeping the whole thing captive and the fork biting on the axle directly. So what I should be able to do is just use a straight slieve with an OD of 25mm and an ID of 20mm (or just a big bigger actually) tapped to the same thread as the thread on a stock DRZ axle. The DRZ axle just needs to have its thread tapped a bit more so that it runs the entire depth of the pinch area in the fork leg and the slieve itself the same width as the pinch area of the fork leg.

Then all I do is stick the slieve in the LHS fork leg in place of the axle and tighten up the pinch bolts. Insert newly tapped DRZ axle into the RHS fork leg, run it through the hub and associated spacers, then tighten into the now captive slieve on the LHS fork leg. Once done up to a reasonable torque then just pinch up the RHS fork leg on the 25mm part of the axle.

Simple, when you actually stop to think about it #-o

[Wobbly]

For those wondering what i'm rabbiting on about, a diagram ensues :)

http://vsmr.net/albums/bitsnbobs/DRZ_KX_axle.jpg

This is looking at the axle/hub from front on the bike, so the RHS fork leg goes on the left and LHS on the right. The RHS of the axle just needs tapped more so that the internally threaded slieve can bite over the whole of its length. The fork legs pinch on the larger part of the axle on the RHS (left) and onto the slieve on the LHS (right). Simple right :roll:

[Daws]

I was going to post a helpful reply but as I read through the thread I realised you managed to work it all out by yourself - You could have saved yourself a lot of typing!

[shane]

I was going to post a helpful reply but as I read through the thread I realised you managed to work it all out by yourself - You could have saved yourself a lot of typing!
my thought also ,i had to do it when i put a set of cast wheels in my crf for the first time , but neil you answered you own question , better than i could so stop typing and get to work :D

[Wobbly]

You know, when the KX axle lobs up in the mail in the next few days, it'll probably just bolts straight up knowing my luck :lol:

[megahead]

Neil you amaze me and yet confuse me :lol:
But you know it wont be complete without a trip to bunnings
row 6 front end kits and spacers

[Wobbly]

Ah, but I had some forethought before, and made sure I stocked up well on zinc plated 5/8" washers ;) :lol: